Report of inspection trip to France, Italy, Germany, Holland, and England, made during the winter of 1921-1922. Technical supplement

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AIR SERVICE INFORMA N CIRCULAR
(AVIATION)
PUBLISHED BY THE CHIEF OF AIR SERVICE, WASHINGTON, D. C.
Vol. IV November 1, 1922 No. 391
REPORT OF INSPECTION TRIP TO FRANCE, ITALY,
GERMANY,HOLLAND,ANDENGLAND,MADE
DURING THE WINTER OF 1921-1922
TECHNICAL SUPPLEMENT
By
Brigadier General William Mitchell, 1st Lieutenant Clayton Bissell
and Aeronautical Engineer Alfred Verville
WASHINGTON
GOVERNMENT PRINTING OFFICE
1923
Ralph Brown Draughon
LIBRARY
APR 25 2013
Non•Depoitory
Auburn University
CER'l'IPICATE: By direction of the Secretary of Wai·, the matter
contained herein is published as administrative information and
i , required for the proper transaction of the public business.
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TABLE OF CONTENTS
FRANCE.
Resume of French research, development, and ser·.·ice aircraft ................................ _ ......... _. __
French program for new airplanP.s .... _ ........ _ .. __ . _ ... ___ ......... _ .... _ .... ·-................. _ ..... __ .
French type specifications ........... . . ... . _ . __ .. _ . ... _ .. .. __ .. ___ _ . . _ .' . . _ .. _ .. _ .. _ .... _ . .. _ . _ .. . . . ... . _ . _
French aerodynamic studies ..................... _. __ ...... _ ..... _ .. _._ .. _ ... _ ... _._ .................... _.
Wibault design drafting system ...... . _ .... . . . _ . . . . . _ ... . ..... . . . .. . ... . .. . __ .. _._ .. . _. _. __ .. _. __ . __ ..... .
Bleriot-Spad-Herbemont aircraft .... __ ... _ ...... __ ... _ .. __ .. _ ..... _: ... _ .. _. _ ... __ . _ .. _ .. _ ... _ .. _ ... _. __ . .
Nieuport airplanes ... _. _. __ ................ _ ...... _ ·_ ... ___ ..... _. _ ........ _ ............ __ .... __ . _. _ ..... .
Breguet aircraft ... _ .. _ .. __ . ... _ .. __ . . _ . ____ . __ _ ..... __ . _ .. _ .... . _ . _ . _ . __ . _ ... _ .... _ . .. . .... _ . _ .. ___ . __ ..
Potez machines .. _ ... __ . __ . _ . _ ...................... ___ .. __ .. _ . . ..... _ ... _ . _ . __ ..... _ .... _ .. : _ .... __ .... .
Wibault machines ................ ___ ... __ . .. _. __ _ . ___ .. ___ _ . ___ . . _. __ . ____ . . ..... . .................... - -
Morane Saulnier-Co_ .. __ .. . . __ . _ . _ ....... _ .. _ ...... _ ..... _ . _ . _ ..... _ ... _ ........... __ ...... . __ .. __ . .. . _ .
Farman aircraft ..... __ .... _._ ... · ..................... _ ................. _ ....... _ ............... . ........ .
Hanriot Co ............. ... ... . .... . - . - - - . - .. - . - - - - - ..... - . - . - . . - ... - - - - - - -·_ · - - - - - · · - - - · · · · · - · · - - · - · · - - · ·
Duralumin ....... . .. ___ ... _ . __ .. _ ................ _ ........ _ .. _ ..... _ ... _ .......... _ ... _. ___ ... _ .. _ . . . _.
French motors .......... _ ... _ .. _. ___ . _. ___ ... _. __ . __ __ . __ . ___ __ . ____ .... ____ . _. _ .. _ .. __ ................ _
Hangars. __ . _ . _ ... _ .. _ ......... __ . . ___ ... _ . _ ... ___ .. . __ ...... ___ .. _ . ___ . . ___ .. - .. ... - . - . . - . - - .. - . - . . - -.. .
Lamblin radiators .. _ ... _ ..... _ ........................ ___ ......... . _ ........... - ....... - . - . - - . - - - ...... .
Ex-German Zeppelin L--72 ....... _ ...... . _. _. __ _ . . _ .. __ _ . . . _ .. . ___ .. __ . . . .. .. _. _ . .. . _. _ .. . __ . _ .. _ . . • _. _ ..
French meteorological pilot balloons _ .... __ ... _ . ___ .. _. ____ .... _. __ .. _ ... _ ...... _ ................. _ ..... .
Pescara helicopter ·and h elicoplane ...... _. __ .................... __ . . _ ... _ . _ .... ___ . ___ ... _. __ .... _ ...... .
ITALY.
Page.
7
9
19
25
26
27
29
31
34
34
35
36
37
38
38
40
41
41
41
42
Resume of Italian aeronautical activities. __ . . ____ .. __ ._._._ ... ___ . . . . _._ ._. _ .. .. .... . __ . . . . . .. _. _ . . __ ._ __ 45
Italian type specif cations ................... _. __ ....... ·._. __ .·_ .... _ ................. __ ... ____ ... _ .. . _... 47
Italian experimental station ... _. ___ ._. ___ _ . __ . __ .. . _._ .... _. ___ _ . __ __ . __ _ ._. _ .. _._ .. ____ ................ 50
Italian dirigible ............... , .. ... _ .... _ ... _ ............... __ ..... _ ... _ .. . ... _ .. _ .. ____ . .. . _. .. . . ... . . 50
Savoia flying boats .............. _ ......................... _ ...................... __ ...... ____ ... . ..... _.. 51
Macchi seaplanes ....... _ ... _ .. .. . . ... .. _ .. _ . . ___ . .. __ .. _ . . . ____ ..... . . . ...... . . __ . .. . ... . : . __ ___ .. ___ .. 52
Italian seaplane P . R. B. 1. .. __ . __ ......... . ..... _ ...... _ ..... _ .... _. ___ . ___ .. _ .. _. ___ ... _ . ... . ___ . __ .. . 53
Fiat planes and motors .. _ .... _ , . _ ... __ .. __ . __ _ . _ . _ . _ . _ . _ . __ .. ... _ . _ . __ ........ _ ............ _ ... _ . _ . _ .. _ . _ . 54
Caproni Co ... ___ ......... _ . __ ..... _ .... . . _ .. ... ... ___ .. _- . _ .. _ . ___ . ___ ... ____ .. __ . _ ... __ . _ . . . .. _ .. . ... _ . 58
Ansaldo Co .... _ .. _ ... _ .. _ ... ___ ....... _ .. __ .. _ ........ _ .. __ ........ _ ...... ____ . _ . _ . _ ...... · .. __ ....... _ . 59
Breda Co ....... _ .. _ ..... .. _ .. _. _ .. _ . . _ . ___ .. . _ ... . . __ ... . . __ . __ ~- _. ___ . .. _ .. _ .. __ .. __ . __ .... _ ......... _. 59
Target airplane ........ _ ........ _ . : .......................................... _ . _ .. __ . _ .. __ . _ . __ . _ . __ . . . . 60
GERMANY.
Resume of German research development in aircraft construction .. _ .. _ ..... _ ............. _ ............. _. _ 63
Zeppelin airships ...... _._._ .. _ .... _ ......... _ ... _ .................... __ .... _ .. _ .. _ ... ___ .... . ... _....... 63
Comparison of airships and the use of nondimensional characteristics ..... . _._ . . . _ . . . _ ... __ .. _ .. _ .. _ .. _ .. ____ 71
Zeppelin-Dornier Co ..... __ .. __ . _ .. _: ..... _ .. ___ . _ ....... _ ............ _ ............... _ ........... _ .... _. 72
Zeppelin Staaken planes ..... _ .... . . . ... _ . . ...... _ . _ . _ . .. _ . _ . ___ .. ____ . . __ . __ . _ .. _ . . _ . . . . . . . . . . . . . . . . . . . 75
Junkers Co._._ .. _ ..... _ ................... ___ ... _ .... _ ... ___ .. ___ ..... _ ... · : ........................... 76
Maybach Motor Co __ ... _ .... . ... ... . ... ___ . .. _ .. . _. __ . ____ . _ ... . .. . . ____ . _ .. __ .. _ ... . _ .... __ .. . . . . . . . . . . . 76
Report on B. M. W. motor ........ _._ ... _._._ .. __ ........ _______ ... ___ . . . . ___ ..... ___ .... ___ . .. __ .. . . _._. 77
HOLLAND.
Fokker airplanes ...... _ ...... _ ................. _._ . .- ._ ........ __ ...... __ ... _ ... _ .... _..... . ............. 81
Dutch ail'-service report on the Fokker airplanes .... ______ . _. __ _ ..... _ .... _ .. _ .. __ ............ _. __ ........ 82
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4
ENGLAND.
Page.
Resume of British research development in service aircraft_ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Alula wing ..... .. , ........................................... . ........ . . ...... ... ..... ...... . ... .. ... . .. 96
Air ministry torpedo-.machine specifications.. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
·Rolls-Royce Co. .. .. .. ..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
De Haviland·Co. .......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Gloucestershire Aircraft Co. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Handley Page. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
Bristol Co. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Vickers Co .............. .. .................. . .. ... ...... .... ...... . ...... . . ..... . . , . . . . . . . . . . . . . . . . . . . . 108
Air ministry specifications: Vickers " Vimy " ambulance airplane. ....... ... ... ..... .. . ..... . ... ...... .. ... . 109
Bolton & Paul. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
Short Bros.' all-metal planes ..... . .. .. . . .. ........... . . ... .. . _. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
Siddeley Co.. . .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
Admiralty performance report on the Siddeley "Siskin " airplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Petro flex gasoline tubing .......... .... .... . ...... . .. . ... .. ... •. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Reid control indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
Specifications for Napier Cub ertgine... .... ... .. . .................. .. ........... . ..... . ... . .... . .. . . . ... .. 121
Commercial aviation-London Terminal Aerodrome, Croydon . .......... ... ... ..... . .. . ... . . .............. . 121
Commercial aircraft transportation between England and France. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
GENERAL.
Conclusions on the technical report. .. ......... . ......... .. ............. . . ..... .. .... .. .............. ... .. 1.27
General recommendations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
Recommendation of articles to be purchased in Europe for the United States Air Service Experimental Station at
McCook Field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l 29
FRAN.CE.
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, ,
RESUME OF FRENCH RESEARCH, DEVELOPMENT, AND
SERVICE AIRCRAFT.
French experimentation is concentrated on develop­ment
of all-metal types and, unquestionably, metal con­struction
is the keynote of French development to-day.
The requirement that all t heir airplanes shall be capable
of being stored indefinitely under a'.ly weather conditions
without major harm has had much to do with the domi­nance
of metal construction.
The principal research work that is being conducted
by the aerodynamic section is in the development of
efficient internally braced airfoils, investigations in
stability a-:id in the controllability of aircraft, .more accu­rate
determination of scientific data for mathematical
design of propellers, investigation of the most efficient
control surfaces, the problem of developing suitable
methods of effecting mechanical control fOT large multi­motored
airplanes as an aid to the pilot, in;estigations
as to the influence of interference in all types of aircraft,
the accurate determination of correction factor data for
application from wind tunnel models to full-scale work,
and the exploration into the question of the influence of
very high velocities in correct mathematical interpreta­tion
on general airplane properties.
The future French training types will be studies in all­metal
construction. The Gourdou monoplane is a very
representative type of French single-seater pursuit,
although it is underpowered to meet the new pursuit
requirement. The fuselage, landing gear, and tail sur­faces
are duralumin tubing with steel fittings, very similar
to the Breguet type. Bi place pursuit and reconnaissance
types can be realized with the 500-horsepower engine,
but inasmuch as this necessitates a very heavy machine,
the French _ l:iave so far confi'ned themselves to lower-pow­ered
motors equipped with superchargers to obtain high
performance at altitudes with less structural weight.
Detachable tanks are considered very much better
than the rubber-coated tanks where it is possible to use
them. Most of the French types have been designed and
laid out for long-distance work of an offensive nature.
They require a large amount of gas in order to fulfill their
nnss10nf!. The French have stipulated that the excess gas
to be carried for the cross-country passage to combat
points may be placed in removable tanks to an average
extent of about one-fourth of the total amount of fuel
required. The position installation of these removable
tanks, however, has not been stipulated. It is under­stood
that they are to be placed on the outside of the ma­chine
so as to reduce the cubical capacity of the fuselage .
This will be an advantage in procuring more efficient
aerodynamic outline and partially removes the restraint
and embarrassment as to disposition of equipment, ac­cessories,
and fuel within the airplane proper.
It is significant to note that one of their most important
requirements for their two-place, armored machines is
that they be capable of making a figure "eight" between
two points situated 100 meters apart. The fact that this
must be done at an altitude of 100 meters is a criterion
of the ability of this machine to maneuver for position.
The French require that pilots' seats shall, in all types, be
capable of being regulated in h eight, and armored seats
are provided wherever possible. Silencer apparatus
is to be applied on all their night bombardment ships.
Twin-motored types of bombardment ships have been
absolutely discounted by the French air service. They
have stipulated that all their future multimotored ma­chines
shall be of three or four motors and capable of flying
on one-half or, at most, two-thirds of their horsepower.
Self-starters are to be provided on all their night ships
and the propeller flanges equipped with adapting clutches
for field starting. All their new machines are designed
with provision for self-starters from the cockpit. Their
representative field starter in service to-day is the Odier
type. We have a sample of this starter at McCook Field.
The colonial type airplane (specifications attached)
is to be of such design that it can be easily transformed to
a bombardment ship. It will be multimotored and will
carry a minimum of eight persons. Specifications govern­ing
this type are very interesting. They evidence the
attention that is being given to the development of this
special type for distant work in the colonies and for use
under adverse climatic conditions. They are able to
operate at great distances with heavy bomb load.
On all pursuit planes having fixed gun installations
the cowling immediately around the gun mounting must
be easily removable and' provided with fasteners which
can be adjusted quickly. Under no conditions will they
permit the cowling to be bolted down. The modern
tendency governing bomb installations is favoring the
internal bomb rack for most of their machines where the
size of bombs does not place a limitation on the initial
structural layout. For their larger bombs they still use
external supports.
Comm"unication between pilot and observer must be by
voice without the use of an aviophone. Where this is
absolutely impossible, a passageway facilitating direct
c.ommunication between pilot and observer is required.
Crews are no longer permitted to be placed as in the
Salmson types. Parachutes must be provided for all
the personnel in all their types.
Another impOTtant requirement is that power plants
must be completely changed in eight houra with two
mechanics. Their gasoline pumps must be designed to
feed any one or two of their motors. Starting of the
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motor by hand or whirling of the propeller is to be abso­lutely
discounter! on all types. The specifications aa
to fuel supply requirements for all their different types
are interpreted in terms of sea-level consumption so as
to facilitate an accurate understanding with designers
1'1.8 to actual amount of gas required on all their types.
The development of propellers to resist all extremes of
climatic conditions is being pushed and will be provided
on all their types as soon as possible.
Experimentation ;relative to the development of suitable
duralumin floats is being conducted with their seaplane
work. Deck landing trials are being made regularly
with the idea of developing means to retard the progress of
the airplane on landing and to provide the best methods
to prevent the plane from going over the side of the ship.
Their idea as applied to their ship planes to date has
been the use of a hook attachment, about 10 feet long,
fastened to the underside of the fuselage, immediately
back of the landing gear. It can be dropped by the pilot
and its rear extremity engages the ropes that are set trans­versely
across the deck. These are fa.5tened to sandbags.
This method does not produce a very marked shock to the
machines, owmg to the leniency of resistance produced
by moving the sandbags. Shock-absorbing devices in
the forward extremity of the long metal hook a.re fastened
to the underside of the airplane fuselage.
The French have been attaching considerable impor­tance
to the development of very high speed racing air­craft
such as has been evidenced in the Nieuport Delage
Sesquipla.n. One of the main object5 is to ascertain
from trials in full sea.le the relation between the perform­ances
realized and theoretical performance advance
rom laboratory experiments. It is their desire to deter­mine
standard correction factors that will be applicable
in full-scale tests and to determine the value of different
air foils and resistance fact-0rs at high velocities.
Preparing for and conducting racing meets is very ex­pensive,
but the benefits to be derived for general technical
aeronautical purposes are of great value and open up
technical research and center attention in a new domain
in which everybody is more or less concerned. The
development of pursuit is in a large measure dependent
on the development of speed machines.
A brief reference to the work of the leading companies
in France will give un indication as to the trend of oplnion
and development in French aeronautical circles. These
references are necessarily brief in a resume ot this kind ,
but complete details covering the ships referred to will
be found in another part of this report.
The Spa.cl Co. is still developing monocoque construc­tion
and attribute their faith in it to the superior aerody­namic
outlines that can be obtained. They have procured
superior performance both in endurance and speed for
a given period. Their new single-seater, high-altitude,
pursuit type, and their new two-seater, high-altitude,
pursuit and observation type in monocoque will be com­pleted
soon and should be followed closely. The per­formance
and ultimate function of these two machines
represent the overcoming of inertia of development on
these two particular types. They have been found de­sirable
·by the French for pursuit and are being built to
type specifications in experimental fashion. Full de-
8
scription of these machines will be found under the
proper heading.
The Spad " Side-by-Side " training t.ype is another radical
d eparture for instruction purposes. The trend of opinion
in American and European aeronautical training circles
should be derived and conclusions drawn from it as to the
desirability of this type for our ultimate training program.
It is probable that a conclusive opinion may be reached
in short order by our experience with the new two-seater
Dayton-\Vright training type which has just been com­pleted
and submitted for test.
The Nieuport Co. is still sticking to monocoque con­struction,
and inasmuch as they have been endeavoring
to attain the utmost in streamlining, they consider that
this type construction is best adapted to attain the higher
degree of fineness that is necessary. The performance
obtained during the last four years with the Nieuport 29
has been sufficient evidence of the correctness of their
theory. This machine is probably the best and most
highly developed pursuit ship in the world.
The Breguet Co. 's interpretation of all-metal construction
in their single-motored types is practically the same as
they have used for the last four years and has been giving
entire satisfaction. It is truly representative of French
all-metal standard type construction and satisfactorily
stood the test of servi ce conditions in the World War. It
is still being developed and used by the French air service.
The type of construction used in the Breguet Leviathan
represents a departure from the orthodox method, but is
too complicated to be practical.
The Potez Co. has been working on a different adap­tation
of metal construction in their later models. They
are principally prototypes of some of their earlier machines.
Their master construction ideas are principally toward
the use of duralumin shapes, such as channels and angles
with gusset-joint construction as their characteristic inter­pretation.
Very satisfactory physical evidence of this typ~
of construction bas already been produced, and tests being
conducted will tell how well adapted this type of construc­tion
is under field conditions for production, accessibility,
and maintenance. Their motor mountings are complicated,
although they are very robust. They build the engine
in, frame fashion, and employ a great number ofrivets.
One of their latest models is a three-motored bombard­ment
or passenger-carrying plane, which is their best
interpretation of the French three-motored, long-distance,
night bombardment specifications. It is designed, as
hereafter mentioned , under the specifications requiring
a central fuselage with twin wing motor installation. I
believe that tubing is far more economical frnm a struc­tural
standpoint than this type of construction.
The Wibault Co. has developed a radical interpretation
of a single-motored, night bombardment ship absolutely
different from any of the existing French prototypes.
This machine has been conceived with the fundamental
idea of preserving the most efficient aerodynamic outline
possible. The machine is all-metal construction and has
the entire load of accessories, bombs, and fuel disposed
within the structure proper. This machine has recently
made its first test flights and should be observed closely
with a view to ascertaining the advantage of this type for
the fulfillment of its night bombardment mission.
The metal construction has been very thoughtful]~,
carried out and, although it does not represent the utmost
in simplicity to be desired, it is the most representative
type of up-to-date all-duralumin construction in a French
military machine. This machine has been very thought­fully
designed to meet the specifi cations that have been
laid down by the French air service. The absence in the
major part of their metal construction of a lot of flimsy
sheet duralumin pieces, and the utilization of tubular
construction wherever it has been possible, are the out­standing
features of the Wibault machines. This machine
should be very closely studied to determine wheth er or
not it would be d esirable for us to do experimental work
along the same general lines.
The Wibault Co. is also constructing a single-seater.
supercharged pursuit plane of the " parasol monoplane"
type, motored with the Hispano-Suiza, which should be
very closely observed in its development. If it has the
desired maneuverability, it will represent a type suitable
for pursuit work at altitudes.
9
Mr. Wibault employs fabric for all his surface and
fu selage covering. The advantage is the ease of inspection
of the internal-construction units, accessibility, and ease
of replacement. Deterioration in the field when exposed
to the weather is going to make the covering relatively
short lived, but this d eterioration requires only the
replacement of fabric and not of any major structural part.
This is a point to be very seriously considered in our own
program when studying the design and construction of
ow· future all-metal wings. In considering whether or
not we will adopt metal wings with fabric covering or
metal wings with metallic covering, it should be remem­bered
that the ad vantages or disadvantages in either case
are not alone concerned with the covering.
The Morane Saulnier Co. has designed and built during
the past year :;in internally braced monoplane with ta­pered
wings, powered with three 370-horsepower Loraine
engines or three 400-horsepower Liberty engines. One
oi the engin es is located in the nose of the fuselage and the
other two engines are located immediately to either side
and in the leading . edge of the monoplane wing. The
structure of the machine is entirely of metal elements,
although the wings and fuselage are covered with fabric.
The wing spars are duralumin trellis-type gird ers. The
landing gear is of the two-wheel type with two vees
extending from the bottom of the fuselage out to the
wheels and with the compression truss extending up
from the wheel shock-absorber point to the underside of
the wing engine mounts. The wing is divided practically
into three distinct plan sections, the center section being
of a uniform chord and depth, while the outer sections
from the engine location taper toward the wing tips, both
in chord and depth. The control surfaces are all balanced.
The engines are so disposed as to prevent the blanketing
of the respective propeller-disk areas. The fuel tanks
are situated in the wing just over the outboard engines
and no fuel is carried in the fuselage. Fuel capacity is
sufficient for seven homs' flight with full load. Provision
is made, however, for the immediate emptying of the
fuel tanks, should the necessity arise in flight.
The fuselage is of rectangular section and has nose
radiator mounted for the fuselage engine. Control com­partment
is fitted with two seats ahead of the ,ving, afford­ing
excellent visibility.
A tunnel leading from the control cockpit to both wing
engin es enables the mechanic to make motor ad justments
in flight, and the central engin e, of co urse, ma,y be directly
reached from the control cockpit proper.
This machine has recently been completed and is now
ready to undergo tests. It has been designed, however,
as a passenger carrier and provisions are 1nade for the
location of 16 passengers. However, this machine is
readily adapted for conversion into a bombardment type,
and if the experiments prove out well on this first machine
it will be converted into a military type. It represents
a very novel type a.nd has really been influenced in design
by the advent of the large Zeppelin Staaken type. Being
a three-motored job, it will blend in well with the require­ments
of the French bombardment type specification
req uiTing three motors. Flight tests will be conducted
very soon at Villacoublay, and the results should be
watched very closely .
FRENCH PROGRAM FOR NEW AIRPLANES.
EXPLANATORY NOTE.
The French have laid clown a definite program for
their new airplanes which contains a discussion of require­ments
with suggestions for th eir installation. This pro­gram
for new airplanes has been translated from the French
using as free a translation as possible in order to make the
information understandable even to a layman. In several
instances, however, it was impossib ll'l to give a free trans­lation
and maintain the exact meaning of the French.
In other cases there was some question as to exactly what
was meant and in both of these instances a literal transla­tion
has been given.
Table of French aircraft.
Type. Existing or
ex,perimental. On order.
Pursu it, low altitude._ ................. . Nicuport 29 C-1. Nieuport .
Han riot. Spad.
Spad.
P ursuit, high altitude, supercharged._.. Nieuport.
Pursuit and reconnaissance, 2-place, ob- Breguet.
servation. Spad.
Day bombardment ....
Night bombardment .. _._._ .. _.
Farman.
Haariot.
Salmson.
Potez.
Breguet.
Farman.
Breguet.
Farman.
Ship planes. __ ... . ...... .. . .. ·· -· . . .. _.. Nieuport .
Hanriot.
Torpedo planes .. .. .. __________ .. ____ ................. _
Training __ . . .. __ . __ . __ . . . ..... . .. ... .. _. Hanriot.
Morane.
Caudron.
Spad.
Wibault.
Nieuport.
Hanriot.
Gourdou.
Spad.
Potez.
Morane.
Wibanlt.
Potez.
Latecuere
Spad.
Farman.
Spad.
10
I. GENERAL QUALITIES REQUIRED.
Power.____:_The basic French plan to improve the flying
performance of their aircraft is to ma1re the most efficient
use of power rather than in increa,ing i t.
Of two airplanes which bear the same load with the
same speed at the same altitude, the one using least horse­power
is much t he better, since it permits of greater ma­neuverability,
is easier to land, and has a smaller con­sumption
of heavy, costly fu el.
Number and types oj motors to use.- Light, fast, ma­neuverable
airplanes would necessarily have a single
motor.
E.fficiency.- S pecial attention of the constructors is called
to t he increase in the efficiency of airplanes which can be
obtained by careful study of the lifting quality of -the wings,
of the parasite re3istance of the accessory parts, and of the
efficiency of the propeller.
The lifting q uality depends upon the choice of the pro­file
and upon the re 3istance of the wings.
Actual experience has shown that from a lift viewpoint
the best biplane wings are those which have the lower
plane narrower and which have forward stagger.
Head re3istance of the airplane should be studied for
each part, and the shape of the fuselage will be such that
it will hold all the accessories.
The question of water and oil radiators will be particu­larly
investigated , as will also the air outlets of the fu se­lage,
which actually occasion very great resistance by the
whirls which they cause.
In general , the head re3istance of an airplane of a series '
of separate parts is greater than the sum of the resistances
of the parts considered alone, and much greater than the
resistance of the parts grou peel in a single body even
though the individual resistance is large.
The efficiency of the propeller will be augmented by
the choice of its profil e. The narrow propeller of great
diameter has been shown to be the best simultaneously
by the experiments of the laboratory and direct measures
of the performances on the airplanes.
In all cases, when possible, the propeller should turn
at a low number of revolutions. Gear red uction is inter­esting
if it functions well, even for fast airplanes.
With the present motors, a red uction of one-half could
be considered as desirable on all airplanes_
Such a red uction augments by 9 per cent the efficiency
of the propell er if it is alone on its shaft: P 1=P0 Xl.0():
and by 12 per cent if it is tandem w:ith another propeller :
P 1=1.12 P 0 •
This augmentation of efficiency also holds true for the
greatest speeds actually practiced.
High-altitude airplane.- For high altitudes the deter­mining
element is the weight of the motopropeller group
brought from the useful power to the maximum heio-ht
attained by the airplane.
0
High-altitude airplanes present two totally different
problems.
The first solution involves the use of very [io-h t motors
air-cooled if possible, calculated for fun ctionino- in cold
air at high al ti tu des and provides with a checked feed for
low altitudes, so that the pressure and the temperature
l~orne by the parts migh t not be excessive.
The second problem permits the use of motors calcu­lated
for functioning at sea level. This is accomplished by
feeding gas to the carburetor at a pressure practically
constant This solution involves a turbocompressor.
Airplanes jor medium altitudes. - The airplane for
medium altitude must be easy to fly and must have a
motor without complicated accessories. One designed for
regular functioning of many hundred hours will be the best.
Heavy airplanes . ..:_Heavy · airplanes will certainly have
to be either tlu-ee or four motored to be dependable. These
motors will be chosen p1·imarily from the standpoint of
reliability. Their installation and accessories shall be
completely independent so that the failure of one motor
or any of its accessories will not produce the failure of
several motors such as might be the case if they had acces­sories
in common.
The bimotored plane is the most dangerous to handle
in case of failure of one motor, is the least regular in oper­ation,
and should not be furth er considered .
Stability.-r\.irplanes ought to be inherently stable,
climbing gradually if the motor is accelerated or cildino­normally
if it is throttled.
0 0
When the motors are cut out the airplane should
automatically start to glide at an angle which is slightly
greater than the normal gliding angle of the machine.
In a turn, with motor full speed or cut out, under the
action alone of the rudder, the airplane should ti lt nat­urally
to make the drift negligible.
Compensation of multimotored planes.-In the multi­motored
airplanes a contrivance will be provided to per­mit
counteracting the unbalancing effect from the stop­ping
or the loss of power of any of the motors without sub­jecting
the pilot to additional fatigue. An example of
this is a compensator on the rudder bar to prevent the
plane turning to the right or left.
Longitudinal equilibrium.-An airplane .with a full load
should he balanced longitudinally for ordinary flight con­ditions
with the motor turning at its normal revolutions.
Of course this means at the altitude for which it was de­signed.
It must not be tail heavy or nose heavy.
Manem.>erabi.Zity.- Response to controls should he very
easy so that the airplane will not be fatiguing to the
pilot. The effort required by the pilot should always be
proportionate to the effect d esired.
This result is easily obtained by using as ailerons, ele­\
·ators, or rudders, mobile surfaces relatively long and nar­row,
partially balanced and combined with carefullv con­sidered
fixed surfaces placed before the movable suifaces.
' In all cases the tlu-ee controls should be desio-ned to
require a similar amount of muscular effort in the different
evolutions of the airplane.
An airplane control which can easily be thrown out of
gear should be provided for use of one of the observers
in multiplace machines.
Comfort.- The crew should be arranged in such fashion
as to avoid all unnecessary fatigue during a flight. Seats
with upholstered backs should protect them from vibra­tions.
They should be protected from the oil spray and
the wind by windshields, or better yet, the profile of the
plane should be such that the air flow does not strike
them yet p ermits them to see without interposition of
11
glass or any other transparent substance. They should
be protected from escaping gas.
Visi bility.- The field of visibility of the pilot and ob­server
will be one of the most important considerations in
t.he design of any airplane. Details regarding visibility
for different types of planes are given elsewhere.
Location of the observer.- In the multiplace machines,
one of the observers, at least, should be placed very near
the pilot. close enough to be able to communicate with
him by mice without. the aid of any acoustic apparatus.
Each position should permit t.he use of a parachute. The
pilot in any war machine must not be placed as in the
Salmson.
Durability of ai_rplancs .- AII airplanes to be constructed
, hould he C!1pablc of several hundred hours of efficient
flying wi1"h absolute safety.
They should · be capable of being stored indefinitely
without deterioration.
They should be capable of being kept out in the weathet
without seriom harm.
This demand3 that the win:; construction, including
ribs, be entirely of metal.
Paints, .-arnishes, or protective dopes &hould be used
which would protect the thin sheet metal against climatic
conditions.
Ease oj a~sembly and maintenance.- Assembly should be
simple and easy and covered by brief, clear directions.
This re:iuire, that the parts be clearly marked and that
the instructions cover the system of marking. The main­tenance
should be very ea,y and should not necessitate
the employment of specialized personnel.
l nterchangeabil-ity . - The manufacturers of airplanes
should be directed toward the realization in the near
future of perfect interchangeability of the parts. This is
of great importance where the replacement of unservice­able
parts must be made as rapidly as possible without
skilled mechanics.
Equipment and armament.- All the airplanes should be
submitted with their complete equipment and must
make their trial flights carrying full equipment and arma­ment
prescribed for this t ype.
TI . STRUCT URE STATIC RESISTANCE.
Wings.- As a general principle, the static tests under
the control of the technical section should be made before
the first machine leaves the factory.
For the load applied underneath the wings, the coeffi­cients
of safety to adopt should be the following:
. . S(Vo)"
Pu1smt and comhat planes .. .. 10 To(lOO)
. . . _ _ S(Vo)"
Othe1 au plane~ .... ... ....... t .5 -'l'o(lOO)
ln this formula S is the surface in square meters of the
wings. To is the horsepower at sea level and Vo the
speed in kilometers per hour at sea level.
These coefficients should ce multiplied by 1.5 for mono
planes.
Jf any one of the wires or any one of the attaching meta'
fittings of the wing should be taken away (or shot off),
the win; should re , ist stat ically with a coefficient of one
half less. This disposition is applicable to internal drifi
and wire fittings in the interior of the wings.
The wing should be submitted to dissymmetric static
t ests.
Fuselages and empennaJes .- The empennages should
be built to support in the static tests a load of sand equal
by m2 to three-fifths of the maximum by m2 suppo_rtecl by
-the wing in the static trial underneath.
The fuselages, loacleJ with weights dou ble those which ·
they must carry normally, ought be3ides to support the
empennages loaded as stated above.
To verify their resistance to torsion, they should be
submitted to clissymmetric test.
Landing gear, arle, and ta il skid. - The stress which the
landing gear, the axle 3, and the tail skids should bear before
breaking should be at le!13t equal to fi ve times the static
load with the airplane re iting upon a horizontal surface .
These stre3se3 mmt also h!1ve a horizontal component
equ'll to half of the vertical component.
Elastic cords should be e,tablished so that the maximum
strain may not be surpassed, the machine falling vertically
from Om 50 if it is useJ on a clay airplane; from 1 m if it is
used on a night airplane; and the adjustment should be
such that the elastic bands enter into play effectively,
since the stress should not surpass that which they should
bear at rest.
The tests should be furnished with a checking arrange­ment
so that, in any case, the fixed parts of the airplane
can not touch the ground.
The tail skid should be placed in such a manner that,
after the maximum expansion of its elastic bands, the
rudder and the stabilizer should not graze the earth in
bad field s.
III. DETAILS OP CONSTRUCTION OF TH E AIRPLANES.
Assembly.- Disasserobly, re:i.ssembly, . and transporta­tion
ought to be easy. The wings, particularly, should be
able to be taken apart into pieces of not more than 8 meters
~n length, which can be e3,sily transported by railroad.
Standardi.zatio n.-For the parts for which the technical
section will h'lve specified standard tables, the dimen­sions
figuring in the tables are exclusively specified.
Standard tables are established particularly for the:
Steel. Bolts.
Canvas and bands.
Cables.
Piano wire.
Tapering wire.
Thimbles.
Turnbuckles.
Tubes, round and stream line.
Screw threads.
Cocks, valves, and brass work.
Vlheels.
Wire ferru les. Propeller hubs.
Replacen~ent.-It is necessary that all t he parts which
deteriorate ordinarily more often than the wings be easy
to replace. These pi!,rts are the landing gear, tail skid,
motors, radiator, tanks, etc.
It is indispensable that there be interchangeability of
all assemblies or detachable parts capable of being replaced
in organizations at the front. These different parts ought
besides, to be marked in such fashion as to obviate errors
in setting up (high, low, right, left, forward , rear, etc. ).
- Complete production drawings should be furnished to
permit the rapid manufacture of spare parts, if necessary,
and to insure absolute interchange!1bility.
Mainlenance.-All the parts submitted to strain should
be capable oi inspection and easy replacement. It is
]2
particularly so in the case of the crosspieces or the fuselage , ' hours, with two mechanics and with the ordinary facili­of
the tail-skid supports, of all control cables, guides, or t ies available in a light squadron workshop.
pulleys over which they pass to the interior of the wings The disassembly of important parts, such as radiator,
or from the fuselage, and of all the levers, aileron controls, tank, carburetor, magneto, or pump, ought to be effected
etc., transmitting the movement from the control parts to in less than three hours, without necessitating the complete
the ailerons, elevators, and rudders. removal ot the motor.
Mud gtiard.-The wheels ought to he supplied with Provisions should he made for the installation of such a
removable mud guards to obviate the throwing of mud or type of connections and controls that the power plant may
gravel into the propellers. be removed from the airplane without difficulty in the
Steps.-Steps should permit the aviators to mount minimum time.
into the machine without risk of injury to the wing or any Changing the motor ought not to necessitate the disassem­accessory.
These steps should not permit the entry of I hly of any of the accessories- pumps, carburetors, or
air ~nto the fuselage. magnetos- which might be put out of order.
Seat.- The seat of the pilot should be adjustable in The cowling should be strong enough to withstand at _
height. least 10 disassemblies. Its replacement ought to he
Rudder bars.-The rudder bars are adjustable from one effected in one hour.
of the unified types adopted by the technical section: An opening should be provided for inspection large
Floor.- The floor should be furnished with an arrange- enough to permit access to the parts of the motor which
ment permitting the pilot to see the terrain under him: need periodic surveillance: pumps, pressure gauge or
for example, controlled shutters and floor guard with regulator of the rate of flow, sights. filters, drain cocks,
openwork. stopcocks, magnetos, distributors, contact breakers,
Controls.-All the control cables should be double, with carburetors, jet, constant level, and spark plugs.
separate points of attachment. The cowling, in spite of its removability, ought to be
Wind shield.-All airplanes should be furnished with a water-tight, and ought to potect the aviators, windshields,
windbreak or windshield for each person . and sights from all oil or water spray.
IV. SETTING UP OF THE MOTOR AND ITS ACCESSORIES. Carburetors.-The carburetor mount should be designed
A. General.
Management and Junction.-Every motor ought to be
mounted so that its management may be easy.
It ought to be able to function without difS.culty in any
position of Hight in which the airplane is likely to be
placed. For pursuit airplanes, this means a zoom of 200
meters, dive of 1,000 meters, or glide under an angle of 30° .
For multi-motored ships tl1e feed ought to be assured for
any turn effected with the minimum radius of gyration.
Every motor ought to pick up readily after a descen t
of 2,000 meters with the engine throttled.
Assembly and disassembly.- The motor should be con­structed
as directed by the State and no modifications
destined to diminish the interchange:ibility on the air­plane
should be allowed without the consent of the tech­nical
section.
The replacement of a motor or of a group motor in an
airplane, or of an important accessory, such as the radiator,
tank, etc., must be able to be effected in less than eight
to receive any of the different models of carburetors
adapted to a same type of motor.
Precautions to obviate danger of fire are treated under
the next main heading.
The carburetor and its frame should be heated and
adjustment should be provided to permit an economical
functioning for temperatures of 4.0° to 30° for all altitudes
and at all speeds. The air admitted ought to be warmed.
Hoiirs o/jlight.-The capacity of the tank or tanks for
gas ought to correspond to the number of hours fixed for
the running at sea level of the motors at full throttle.
The capacity of the oil tank corresponds to the duration
of the flight at full speed and at the specified altitude
possible with this supply of gas, augmented by the mini­mum
reserve for assuring circulation and a margin of
safety of 20 per cent. The specific consumption of the
motors increases with use.
The attached chart contains the basic elements of calcu­lations
for the tanks of gas and oil with the present motors
and will be revised as new motors are designed.
13
Table of consiimplions of oil and gas of avialion motors.
Motor. Type.
I Specific
Power con- Hourly Oil
Max- full sumption con- hourly Oil
:Horse- ilnum limited per horse- sumption con- reserve
po\, er pew or T admission power in kilo- sumption in circu-
\
at sea hour 111 grams m kilo- lat10n.
!em! T ,. kilo- (T 1 X A). grams.
grams A.
--- --- ---------- - ----
STATIONARY MOTORS.
~~~f~~:B-o~tci~::: :: : : : : : : : : : : : : :: :: : : : : : :-: :::::: ::::::: :::: Hispano-Suiza .. _ ..... __ . _ .... _. ___ ___ . __ __ __ ______ _ .. ____ ___ _
Hispano Cannon ____ ... · - ___ .... _________ ___ .. ___ . __ . . . __ __ __ _
Liberty- . . _ . . _._. ___ _ -- - - ·· · .. . ...... . . ···· · ·· ···· · ·· ·-··-··- -
Lorraine-Dietrich. __ .. . __ _ . . _ . . __ __ . . . . . ...... . ... . . . .... . . . . . PaJ};~i~~~~~~i::::::::::::::::::::::::::::::::::::::::::::I
gg-_-_-:::::::::::::::::::::::::::::::::: ::: ::::::::::::::::1
RenDa uOlt-.- _-_- -. -_-. ·_-_-_-_-_-_-. - _·_- -. -_-_-_.- -_-. -_-. -_-__--_-_ .- -_-_-__·_-_-_- -. -_-. ·_-. -_-. -_-_-. -_-_ -_-__- -.-.
Do·-·- ·-···-···· · ··- · · ·· ····· · · ···· · ······ ···· · ·· · ·· -·· · ·
Do .. ·-·---- --- · -·----------------- · -·--···- --- --·---··-··
Salmson_
Do .. -:: :: ::::: :: : ~oT~L: ,;L~~--- ::: : : : ::: : :. : :: : :: :I
:::~!:::_:_: _:::: :: ::: : : : : : : : : : : : :: : : : : : : : : : : : : :: : : : : :: :: : : : :: : :I
Do- .. · -·· ·-···-· ·· · ·-·······-·-··-··---·····-·
16 C
16A
8 F
12 C
12 L
S B
12 Da
12 Ch
120
12E
12 Ez
16 F
12 F
12 Kb
12M
9Z
18 Z
9B
11 Eb
9Z
9R
Gas en.cl ~ra-i,ily ianl.s. - 1.be feed of each motor must
constitute an ind ependent assembly for gravity, pump,
and service tank , and in addition any tank must be able
to feed any motor.
Each tank should be able to be filled easily and quickly
with an ordinary funnel and should be furnished with
levels or gauges visible to the pilot. If the breakage of
these levels risks involving the flo,v of the gas, a cock
within easy reach of the pilot should permit cutting it
out of the system.
Gravity tanks, with load of gas, should be proYided at
the rate of one for each motor. These gravity tanks are
designed for continuing the flight for 50 kilometers in case
of accidental emptying of the service tanks. They feed
the motors directly and are protected.
Changing from service to gravity tank should be done
automatically or at the will of the pilot.
Feed at full throttle should be assured automatically
while there remains even l! gallons of fuel in any one of
the principal tanks.
The leakage in a tank should not be able to involve the
emptying of the other tanks.
Cocks optionally managed by the pilot should permit
the isolating at will of any number of these tanks.
The pilot should be able to withdraw the gas in the
full tanks at will, either by an automatic arrangement
of pump or exhauster or by a hand pump made in such
a fashion as to utilize all of the gas.
The use of tanks under pressure is forbidden.
The permanent refilling of the grav ity tanks should be
assured at will by the normal system of feed and by aiding
with hand pumps. The flow , in the second case, should
be sufS.cient to assure the normal functioning of the motors.
The automatic valves are completed by safety cocks. A
cock, manageable by the p ilot, should permit the cutting
out of any one of the tanks, the carburetor, or the pump.
The supply tanks are furnished with an overflow pipe
with circulation sight and of a diameter double that of
450 \ 460 420 0. 250 105 8 4
800 900 800 . 260 210 30 6
300 320 280 .245 70 0. 5 4
450 450 420 . 250 105 8 4
400 410 370 . 240 92 6 4
275 275 240 . 250 60 4 3
370 390 300 . 250 75 8 4
500 500 . 250 125 10
340 340 320 . 230 75 75 4
500 520 480 . 230 110 18 5
500 550 480 . 230 110 18 5
600 690 640 . 240 155 23 6
300 330 280 .250 70 6. 5 4
450 460 380 . 260 95 11 5
600 590 540 . 260 140 15 5
230 260 230 . 245 57 8 4
500 560 460 . 235 110 20 6
130 135 125 .285 34 8. 5 2
200 200 180 . 380 68 11 3
120 130 120 . 285 33 6 2
170 170 150 . 280 42 7. 5 2
the intake ; the opening to the atmosphere should be made
in a zone with a current of air.
Each pump should be able to feed any one of the motors
and to have a maximum flow sufS.cient for the consumption
of two motors.
The tanks are establish ed in conformance to the specifi­cations
governing them.
Liibricalion .- The lubrication of the motors should be
done automatically, not demanding the attention or
action of the pilot in the course of flight.
A control arrangement of the lubrication (manometer,
sight, etc.) should be installed with a cock permitting
isolation in case of bre(tkage.
It would be advantageous to connect to the motor a
system of direct injecti~1~ of warm oil in the tubes which
supply the bearings before starting the motor.
The valve limiting the oil pressure, and the oil filter
should be accessible and easily disassembled.
The tube connections should be strong enough to per­mit
effective clamping and provided with a control de­signed
to prevent their coming open. Measures should
be taken to prevent the d eterioration of the hose connec.
tions by the extreme sharp edges of the metallic tubes.
The ligatures should be made with rings.
The outlet tube of oil from the tanks should be sur­rounded
with a strainer at least a centimeter high.
The oil should be maintained during flight at a tempera­ture
lower than 70° and higher than + 10° for mineral oil
and +5° for castor oil, whatever may be the outside tem­perature.
This is to be done by means of radiators and
nonconductors.
All the tanks should be surrounded by cork and the
outside tubes should be insulated.
The blow valves of the motors and tanks should be
arranged to obviate loss of oil by throwing oil vapors on
the pilot. ·
All the tanks should be, as nearly as possible, in load
on the pumps in order to utilize gravity to the maximum
and to reduce the chances of unpriming the pumps.
14
Cooving.- The water-cooled motors should be furnished should prevent the displacement of these cocks and levers
with a thermometer indicating the temperature of the under the influence of vibration .
water at the intake to the radiator (for airplane type a The cocks and levers should all be furnished with leg­thermometer
should be allowed for at the outlet of the ible indicating dials. The lever controls of the carburetor
radiator. ) should bear a special notch necessitating a movement for
The radiators should be nlaced as well as possible for being freed and provided with a stop corresponding to
protection from vibrations and should be supported com- full limited throttle admissible at sea level. The altitude
pletely. either by the motor or by the fuselage , and rein- at which t-0tal admission is admissible should be print.eel
forced at the points of support. Water-tightness should upon the instrument board. The carburetor controls
be assured even if there should be a local tearing of the should. so far as is possible, be synchronized so their
fi xation rivets. successive positions indicate the progressiveness of the
The different fittings should be reinforced by small number of revolutions of the motor.
rings. The water admission should be designed for using Ignition.- The wires should be well insulated and ter­the
flow with the minimum of resistance. The flow of minated by unhookable clasps. No metallic parts should
the radiator in the weakest section and under a load of be found less than 1 centimeter from the ends of the long­Om
40 of water should be at least equal to that of the est spark plugs used .
water pump of the motor under the same governing load A separate switch should permit the stopping of .each
over the cylinder heads. motor. and a master switch should permit the stopping of
They should carry an empt:i, ing arrangement permit- the whole group of motors.
ting complete evacuation of water, or refilling through 11Ianifolds.- The manifolds should be as short as possi­the
bottom. The stopper for this arrangement should be ble, with streamlined shapes, constructed with the mini·
of standard dimensions. At the intake a fine filter should mum number of elbows, and arranged with supports and
be installed to stop the impmities. This must be acces- flexible connections to obviate breakages under the influ­sible.
At their outlet a fixed filter with large mesh for ence of vibrations. They ought to be easily accessible
stopping the grains of solder should be provided. throughout their whole length.
The radiators for any type should be established on a Account should be taken of the load and the resistances
model in such a fashion as to be interchangeable in an in the dimensions of the pipes, wliich should permit a
airplane. load high er by 50 per cent at least, than the necessary max-
The highest point of the water circulation should be at imum under the most unfavorable circumstances.
least Cm 60 above the most elevated point of the motor Manifolds for gas, oil, and water should be immediately
high point water system and should be furnished witli an recognizable by their color. Special connections should
emptying stopper of a standard type. The high local facilitate this division from the motor to reduce to 'the
points for the different positions oft.he airplane should be minimum the number of flexible connections in sect.ions.
provided with tubes connecting tliem to the higher level. Flexible connections should remain in good condition
In any case, the water reserve should be placed above the for at least two years.
higher level of the motor water system high point for a Apparatus for the emptying of the t ubing should be
20° angle of ascent or descent. closed up, not by stoppers, but by special cocks.
The cooling surfaces of the radiators should be calcu- Silencer.- The silencers must be easily removable.
lated in such fashion as to assure a maximum difference They should be as effective as possible, particularly for
of temperature of 65° between the sunounding atmos- bombardment planes. Tho pilot and bomber should be
phere and that of the water at the outlet oft.he cylinders, able to hear each other. They should conceal the glow
at sea level, in the regions of France. This difference is and be invisible at nigh t. They should be able to resist
to be reduced according to the latitudes for colonial air- vibration and expansion ·proceeding from h eating. Their
planes. cleaning should be simple. The total absorbed power
A simple. strong apparatus should permit the regu- consumed by their weight, loss through checking of the
lation of the temperature of tlie water dming fligh t. Its gas, and the head resistance ought to be lower than 5 per
controls should be double and, in case of breakage, should cont of the total power of the motor in fast airplanes and
automatically return to the position of the maximum 8 per cent in bombardment planes.
cooling. The exhaust gases should be discharged at a distance
The radiators should be protected from earth thrown from the aviators, in order not to interfere with firing or
up by the propeller. observation, and must consider the direction of the suction
Cocks and levers. - All the cocks and levers which must of air by the propell er and of the slipstream eddies. This
be managed in flight should be in easy reach of the hand. disposition at the side of the fuselage presents some advan­Duplicated
cocks and levers should permit the secondary tages from tlus point of view.
pilot to manage the motor in case of necessity. Their Starting device.- All the motors should be supplied with
dimensions and their posi tion should permit of comfort- a starting device on the ·dashboard , not requiring the
able and effective management, even by hands covered whirling of the propeller by hand and assuring departure
with big gloves and in spite of a resistance of about 40 in less than five minutes regardless of temperature.
kilograms. All the hubs, in addition, should be furnished with a
Control cocks witli needle valves should be completed propeller-hub clutch on the fron t of the propeller, permit­by
cocks of one-quarter revolution, permitting rapid clos-1 ing starting of the airplane motor with an airdrome mechan-ing.
They should be water-tight, Some safety devices ical starter. _
15
Acc.essory controls.- T achometer, manometer, and con­nect.
ions should be of standard type. Gasoline-pump
controls should be standardized for each of the typ es.
Flexible controls are allowed only on condition that they
have no elbows.
Engine supporls .- -The motor bed and the wing fitt.ingE
should be able t.o resist'the maximum couple of the motor.
with a coefficient of safety of at least 7, in ord 3:- to ta 1,c
account o[ vibrations.
B . . .Measures of precaution lo take against f ire.
Causes of fire on an airplane proceed:
1. From the functioning of the motor and its accesso
ries, and from accidents in bnding.
2. From conditions of special present use in war (hits
from projectiles, incendiary or otherwise).
3. From installation of special apparatus ( compresseC:
gas, different electric installations, etc.).
Only the two first groups will be considered in this note
The appliances and special apparatus whose installation
might be a cause of fi re ought each to he studied from
this point. of view. It is impossible to establish precise
rules of priority.
l. Causes of fire proceeding from the motor and its ac­cessories.
The danger of fire proceeding from the motor can bC'
caused by :
a. Gas from the exhaust.
b. Disposition of electric ignition.
c. Backfiring in the carburetor.
cl. Excessive accid ental leaks in certain parts of the
motor.
In order that fire might spread it must meet a combus­tible
substance- wood, canvas, oil, gasoline, or gasoline
vapor.
For this reason no deposits of gas or oil should be al­lowed
even momentarily . They should he disposed of
immediately by effective ventilation. Possibility of
leakage of gas and oil ought to be reduced t.o the min.imum.
a. Exhaust gas: Particular precaution must 1e taken
at the joints of all flanges to prevent the entry of
exhaust gas into the interior of the cockpit .
The parts of the airplane near the exhaust, and the cock­pit
in particular. should either be metallic or protected by
fireproof covering (asbestos in sheets or in strands) . An air
current of at least 2 centimeters is a good insulator.
Exh aust gases ought to be well away from the garnline
manifolds, tanks, pumps, carburetors , and entirely apart
from closed spaces where gaeoline vapors might accumulate.
In case t he exh aust gas is used to warm the carburetor,
the manifolds of warm gas ought to be perfectly tight.
carefully installed, and the gases discharged far back
from the carbmetor intake.
b. Ignition apparatus: The high-tension magnetos and
their leads are to be inspected very carefully.
Sparks which can fl ash between the high-tension leads
or their ad jacent metallic parts and the points where the
circuits present, a. continuous discharge are likely to
ignite the gasoline vapors. This, then, is the pl~ce to
use sure insulations and strong connections provided with
safety attachments.
Insulations generally used for the covering of high­tension
leads , a.re easily destroyed by the action of heat.
If placed near a. very hot motor wall, they can melt and
short-circuit, frequently causing fires.
The lea.els ought in no case to pass under the gas pipes.
c. Backfiring: Backfiring is ca.used by bad functioning
of the motor, carburetor, or, more rarely, the ignition.
The latter is indeed rare, but can not be completely
a.voided .
Knowing the gravity of the consequences, the adap­tation
of the motor to the airplane ough t to pe1·mit all
backfiring without the least clanger of fire.
Realizing that the most improved motors still have
clanger of fire, it is essential to stop or to limit the spread­ing
of the flames in such a. manner that the~r may not reach
an iuclosure of gas or find inflammable bodies.
For this the following principles should be applied:
(a) Either (l ) lowering the temperature of gas by wire
gauze, or (2) mech anical isolation by automatic valves.
(b) Complete evacuation to the exterior of the fuselage
of the dangerous flames which the preceding contrivances
would have allowed to escape.
For greater sec uri ty t he drawing of air from the motors,
which serves at the same time for evacuation of the gases
from the return and for the drawing in of fresh air in normal
functioning, should bear no communication with the in­terior
of the cockpit. This last disposition is to bem on
all installations. Upon the p assage of th ese gases the nec­essary
heating can be arranged .
Wire gauze can be rep laced by other coolers, such as the
Lela.rge device, which operates by subdividing the ignited
mixture and the ca.Jorie " drainage" by means of aluminum
spheres in a box which remains permeable to air.
E vacuation of gas in excess. - Wheu starting the motor
and during certain maneuvers in the air, especially in a.
dive , there is often considerable entry of gas into the
air-intake pipe.
It is essent ial to prov ide drain nozzles to the exterior,
connected to ea.ch of the low points of the intake 'manifold
at " relatively·" low points, to be determined for the dif­ferent
positions of the airplane (normal flight, climb, glide,
or dive). If the carburetor is not leak proof. an overflow
outlet tube should be provided at the constant level.
Carburetor ancl.feed. - Ca.rburetors ought to be as air-tight
as possible, and the heating of the gases and their speed
in the manifolds sufficient for any altitude·. Feed ought
to be assured in all positions and under all cond it.ions of
flight. Feed under pressure should be prohibited because
it is too delicate, too sensi tive to variations of alt itude,
and to the amount of gas in the tanks.
Cut-out.-The cut-out should be very accessible and of
sure functioning to assure stopping the motors in case
of accident in landing.
Tank.-To a.void clanger of fire in certain cases of bad
landings, ·the dropa.ble tank mentioned hereafter is in ter­esting.
2. Proper special protection to au airplane in case of war.
There are special dangers of fire to an airplane in case
of war proceeding from hits by enemy projectiles. Or­dinary
projectiles can inj urn the feed lines and ca.use leak­age
of the gas where it is likely to come into contact with
the hot parts of the motor. Failure of gas to the carburetor
produces back-firing, which is fed immediately by fuel
leakage. Incendiary projectiles introduce new and dan­gerous
direct ca.uses of fire.
16
Every effort should be made to reduce to he minimum
the dangerous aresi, and to d evelop the manifolds. Protec­tion
of the fuel tanks is obtained by the following means:
a. A special complete exterior envelope of layers of
rubber and Lanser-Dunlop trelliswork, which is nonleak­able
in spite of perforations. In order for this covering to
be effective, the sheet iron making up the tanks should be
thin and ought not to be under pressure (_another reason
for prohibiting pressure feed ).
b . Rapid action release cock (30 _seconds &.t the max­imum).
c. Dropable tanks designed specially to function in
spite of any deformations due to its penetration by a pro­jectile.
For the small reserve tanks protection is .obtained by
the coverings stated above, by armor plate, or by a double
metallic envelope with an inside lay~r of a special material
of the Daigre make.
Propellers.-Propellers ought to be · designed for air­planes
and motors in such manner as to furnish at the
altitude of use and in horizontal flight the maximum power
compatible with the operation of the motors at this altitude.
The efficiency under these conditions ought to be at least.
75 per cent and ought not to fall below 60 per cent for any
uf the other conditions of flight. With wooden propellers
the maximum permissible· linear speed at the tip of the
blades is 270 meters per second.
As a general rule the coefficient of safety corresponding
to the rate of strain of the material ought not to fall below
4 for army corps, reconnaissance, and bombardment air­planes;
and not below 3 for pursuit airplanes.
The propellers should be perfectly balanced.
The airplane being placed on the !!round in line of
flight, the minmum: distance between "'the ea~·th and the
lowest point of the circle swept by the propeller ought to
be equal to om 25 (d) and , in all cases, higher than om 45 ,
(d) representing the distance between the lowest point of
the circle swept by the propeller and the point of contact
of the wheels on the ground before the landing gear.
The instruments on the board , and the compass also,
ought to be entirely visible to the pilot.
They should be easily seen also by the relief pilot. If
this can not be done, he should be given an altimeter, a
watch , and a compass.
Installation of map cases of the regulation type should
be provided for each aviator. The map case should be
able to turn in its plane, which should be perpendicular
to the line of vision of the aviators.
VI. ARRANGEMENT OF THE ARMAMENT.
A. Firing through the propeller.
J. Vickers guns should be set up in such a manner as
to permit access, ,\ith thick gloves, to all the control
levers and to the different parts of the synchrorrizers.
The top p lane of the machine guns should be at the height
of the shoulder. Their installation should be from 30 to
40 centimeters and the wind shield should be placed in
such a manner as not to hinder access, among other things,
to the loading handle on the left-hand machine gun.
2. The sights used should be either a telescopic sight
or a ring-and-bead sight. A natural line o.f vision should
permit direct aim. The aiming field of these devices
should be free from all obstacles. They should be fixed
to a rigid part of the airplane in such fashion that vibra­tions
should not bring about any disorder. Aiming
ought not to necessitate more than slight movements of
the head of the pilot.
3. Disassembly of the machine gnns ought to be made
in 10 minutes.
The forward and rear axes of fixation ought to be quite
accessible. Alignment of the machine guns ought to be
done by arljusting parts situated in the rear.
4. A tangent brought from the eye of the pilot to the
cowl of the airplane, in the t ransversal plane of the pilot ,
ought t.o make 35° to 40° with the horizontal.
5. Links should be received for at least one machine
gun. Cartridge cases should be ejected outside the
machine.
Rear propellers should be protected against earth being
thrown against them by mud guards placed on the land- 6. Cartridge boxes should have a s.urface minimum of
ing-gear wheels or by some other device. 1,500 square centimeters per machine gun. They should
:he p_ropeller hubs of the standard type should be sup be moveable and their loading extremely easy.
phed with standard propeller-hub clutch with a view to 7. Finally, the cowl should be quic~ly removed and
being started by the mechanical ~tarter. An entire new sh~uld not be fixed ~o the rest of the aUJ)lane except by
system of hub motion should be studied bv the technical ;~vels or shafts which can be instantaneously removed.
section before adoption. · e use of bolts should be absolutely forbidden.
The manner of attaching the propellers to the shafts I B . Machine-gun tou?"elles.
ought to be such that assembly and disassembly of the · .
propeller may be effected on the airdrome in less than an :· Installatilon of mac;hine-gun tourelles upon recon-hour.
naissance anc two-seater fighter airplanes:
The type of tourelle to be mounted upon the airplane
V. ARRANGEMENT OF THE COCKPIT INSTRUMENTS AND I sh~uld be deter~ned by the technical section. Placing
INDICATING APPARATUS. of it upon the au-plane should be studied before approval.
Cockpit instruments are necessarily of regulation types
and should be installed in a urriform manner determined
by the techrrical section.
T~e tachometer, altimeter, watch , and speedometer
particularly should be placed on the instrument board
according to a well-e3tablished aITangement. Provision
shoul~ also be made to r eceive, in addition, the different
manometers, thermomet ers, levels, et c., used on an air­plane.
The field of fire should be as great as possible. It should
be at least an angle of 80° upward and the dead angle
under the fuselage to the rear should be reduced to the
minimum.
The tomelles sh9uld be placed so as to interfere as little
as possible with the commurrication between the pilot
and th~ observer. At the side of the pilot, it should not
be possible to pass the gun in the low position, but for all
other sectors the rotation of the tourelle should permit
every possible position of the guns.
17
The diameter of the base ring of the tourelle is 800 ! A trapdoor which can be opened quickly or some other
millimeters. I device should be provided to obviate the entry of air
The diameter of the axis or yoke bearing the guns is I into the fuselage.
9:!0 millimeters. Accordingly, a free space of at least A device should be provided to prevent the guns from
950 millimeters diameter around the transverse ring is attaining an angle of fire which would be dangerous for
necessary for the passage of the supporting shaft of the guns the tail of the machine in the course of combat.
in the low position.
Vertical firing under the airplane will only be possible
for a fuselage having less than 920 millimeters width.
Stops or devices should be provided to prevent the guns
from firing into the field of the propeller.
Field limiters are provided for the tourelles in the
cases where guns could touch the propellers.
The tourelle ring should be perpendicular to the plane
of vertical symmetry of the fuselage and parallel to the
line of flight.
The fixed circle of the tourelle is mounted on a wooden
C. Installation of Lewis machine giin siipports.
In certain particular cases it may be necessary to con­struct
special supports in the airplane.
Gun mounts which are not of standard type or con­structed
according to the specifications of the military
aeronautical authorities should be carefully studied by
the technical section before acceptance.
D. Ammiinition boxes for the Lewis machine guns.
circle which should never be omitted. There should be provided for each tourelle or machine-
The points of attachment of the tourelle base to the air- gun support the regulation number of ammunition boxes
plane should provide a suitable mounting upon which the corresponding to the number of rounds required.
wooden ring may rest. The clamping of the screws or The magazine racks should be placed in easy reach of
bolts must not involve any deformation likely to hinder the gunner and arranged so as to permit the easy replen-the
rolling of the tourelle in the transverse circles. ishment of the guns during firing.
The attaching wires or bolts fastening to the fuselage The general disposition of the ammunition holders for
should never engage the metal part of the tourelle. These the Lewis machine guns and their installation in the air­wires
or bolts should hold only the wooden circle and plane should in each case he approved by the technical
should be placed at points as far as possible from the section.
places of attachment of the wooden ring with the trans- All devices supporting movable guns should be easily
verse ring. and rapidly managed and should be furnished with an
As the gunner's belt is fastened to the tourelle the equalizing system.
mountings of the transverse ring and the airplane should Stops or devices intended to prevent the guns from fir­be
capable of resisting a tearing-out strain of 400 kilograms. ing into parts of the airplane which might be hit should
The distance between the position of the tourelle ring he provided.
and the floor should be 950 millimeters. I
Balanced tourelles.-Owing to the difficulty of maneu- '
vering tourelles on fast airplanes, the latter should be
provided with a device intended to neutralize the effect
of the wind blast. This supplementary device should
be placed in the fuselage when possible and protected by
shields.
The airplane designers should be responsible for the
mounting and functioning of these compensating devices.
2. Installation of tourelles on bombardment airplanes :
On airplanes of the bombardment type, generally
having very large fuselages , tourelles of 1 meter in di­ameter
or more are provided .
The distance from the position of the tourelle to the
floor of the airplane should be from 850 to 900 millimeters.
The technical section will designate the special condi­tions
of the mountings of these tourelles.
Firing under the fuselage. - For permitting firing under
the fuselage, steps should be installed in the rear cockpit
on each side of the fuselage.
The supports should be mounted in such a manner that
the rear gunner can see below the fuselage and fire the
lower guns without leaving the tourelle.
The field of fire should include: In the plane of longi­tudinal
symmetry of the airplane, from the vertical down­ward
as far as the tail skid, and from any part of this plane
25° to left and right.
The cross braces of the fuselage should not interfere
with firing or with dismounting or reloading.
14799-23--2
E. Arrangement of bombardment airplanes.
l. Field of visibility and installation of sights:
General requirements.-The pilot and the bomber should
be as near as possible to each other and be able to com­municate
easily by signals and voice without aviophone.
Field of visibili ty.-Visibility of the pilot: In normal
position the pilot should have a field of minimum visibility
from 50° to 60° toward the front from the vertical and a
lateral field of 15° to right and left. No currents of air
should be permitted to enter through the hole made in the
floor and a closing should protect the pilot from the light
of searchlights on the ground.
Gradometers and inclinometers, visible at night, parallel
t.o the center line of the airplane and placed according to
the longitudinal center line of the visibility opening,
should b·e provided.
Visibility of the bomber.
(a) On the exterior of
(b) In the interior of
the cockpit.
the cockpit.
In the case of a tractor airplane, the bomber requires a
field of 75° toward the front, and in addition, in the case of
bimotored airplanes or machines of the pusher type, a
field of 10° in the rear.
In the case of a tractor airplane, the opening in the floor
should have a field of 70° toward the front, attainable with
an adjustable seat. In the case of a multimotored air-
18
plane or machines of the pusher type, they should have a
field of 70° toward the front, 10° toward the rear, and in the
trans,·ersal plane a field of 30° from any part of the center
line of the window seat without putting the bomber in an
uncomfortable position.
Sights.-Sighting should be provided for either in the
interior or the exterior. The best place is on the exterior
of the cockpit, at the right. But, when in this p,osition,
aiming will not fulfill the conditions of the exposed fields
below, or it will be dangerous (neighborhood of the pro­peller,
interference caused by the lower planes); aiming
should be provided in the interior.
Exterior.-The field of the sight should be cleared of all
obstacles likely to interfere with aiming (wheels, axles,
generators, bomb racks, etc.) in a field from 75° forward
and 10° backward.
The bomb-rack controls should be placed in easy reach
of the bomber while operating the sights.
Interior.-The sight should be placed in the front part of
the cockpit on bimotorairplanes. It will have a field of fire
provided for in the preceding paragraph on the bomber's
visibility. It will be placed in such manner that it may
be used without trouble by the bomber. An articulated
device should fold it down when not in use, clearing the
position of the bomber. The bomb-rack controls should
be in reach of the hand during sighting, preferably at the
right. The sighting hole should be capable of being
cleared entirely of all transparent substance for aiming
at night.
2. From the point of view of bomb racks: All airplanes
should be designed in conformance with specifications,
using stanclarclizecl bomb racks determined upon by the
technical section. ·
These bomb racks differ according to the nature of the
projectiles carried and can be classed as follows:
1. Bombracks G. P. for bombs of 100 or 200 kilograms.
These are carried horizontally under the wings or under
the fuEelage.
2. Special bombracks for bombs of 500 or 1,000 kilograms,
being carried horizontally under the fuselage.
3. Horizontal bombracks, Michelin No. 3, carrying all
present projectiles from 10 to 100 kilograms, mounted in
the wings.
4. Vertical bombracks for bombs of 50 kilograms, being
carried in the interior of the fuselage.
5. Vertical bombracks for bombs of 10 kilograms, being
carried like the preceding.
6. Horizontal Michelin bombracks for bomb flares, be­ing
carried under the wings (two bombs) or on the vertical
sides of the fuselage ( one bomb).
Bombracks G. P .- G. P. bombracks for bombs of 100,
200, 500, and 1;000 kilograms are of a standard type. Ex­amples
of mounting can be furnished by the technical
section upon request.
Horizontal bombracks. - Michelin horizontal bombracks
are made in 32 or 40 cells and carry either a number of
10-kilogram bombs corresponding to the number of cells,
or one of 50 kilograms in place of every four of 10 kilo­grams;
or one of 100 kilograms in place of every six of
the 10-kilogram bombs.
Vertical bombracks.- Bombracks for vertical bombs of
lO kilograms are made for 4. 5, 8, and 10 bombs, grouped
upon a single row of 4 or 5 bombs, or upon two braced rows
(216 millimeters square, sideways, per bomb).
Vertical bombracks for bombs of 10 kilograms, with
e']ual bulk, carry four time3 more projectiles. These
vertical bombracks are compartmented boxes whose di­mensions
depend on the number of bombs (216 milli­meters
square, sideways, per bomb of 50 kilograms or for
four bombs of 10 kilograms). They should be supported
by a special framework for 50-kilogram bombs and for
LO-kilogram bombs.
The bulk of the 50-kilogram vertical bombracks is about
om 35 on top of the frame and 1m 10 on the bottom of the
frame. The bulk of the 10-kilogram vertical bombracks
ts about om 20 ou top of the frame and 1 m 10 on the bottom
of the frame.
They should be easily removed from the lower part of
the fuselage. ·
The minimum space between the spars of the wings of
J,irplanes receiving bombs in the fuselage should be 1m 100
(dimension taken on the interior of the spars).
The release mechanism on the top part of the bombracks
.ihould not be joined with the top structure of airplane
incl should be easily accessible. Lateral inspection doors
3hould be provided in communication with those of the
bombracks.
With the airplane resting on its tail skid, the distance
from the ground under the spars of the lower wing should
be 1m 30 at the minimum in the case where 50-kilogram
bombs are to be placed in the interior of the fuEelage.
The under part of the lower wings and of the fuselage
between the wheels of the landing gear in the bimotored
planes should be absolutely free from all cables, tubes, or
other encumbrances likely to interfere with the suspension
or fall of the bombs.
In the monomotored planes, the lower plane should be
free of any obstructions immediately underneath, be­tween
the wheels of the landing gear.
Control positions.-Release handles of the bombracks
upon the bimotored airplanes should be on the right side of
the front cockpit, mounted so that bombs can be released
while sighting either in the interior or on the exterior.
Auxiliary controls should be provided near the pilot.
Control of the bombracks is generally done by a bare
cable over a pulley or through a copper tube.
Passages.-The passage for going from the front cockpit
to the rear and giving access to the bombracks should be
400 millimeters wide at a minimum. The height from the
floor of the passage under the top structure should permit
the passage of a man without difficulty.
Passage from the bomber's position to the pilot's cockpit.­Cross
structures between the pilot's post and the forward
post ought to be avoided as much as possible or at least
should be high enough so that the passage may be made
without difficulty or interference with the pilot.
The technical section will communicate to the con­strnctors
of bombardment airplanes the detailed char­acteristics
of the above material and also the detailed
conditions of assembly.
19
vn. ARRANGEMENT OE' ELECTRICAL EQUIPMENT. I favorable angle, the ground from the vertical to 30° for-
. . . ward. This may be done directly by a window o-round
Generators.-All motors are designed to dn ve electric I di . 1 b . h ' 0
. . g ass, verging ens, y a pen scope, or some ot er appara-generators.
Th~ mstallation of_ generators should conse- tus whose bulk will not interfere with movements.
quently be pro.V Id.e d for on all a. ir.p lanes. . Mo reover, th e o b server s h ou ld see a 11 the fi e ld w h"1 c h
·dI f the operation 1s made by dnvmg belt, it should be pro- tl -1 t Th. ·tat 1 · th 1 ·th . h .
11
. . escapes ie p1 o . 1s may necess1 e eanmg over e
VI ec :"1 a tig tenmg pu ey arrangement pernntting side.
the, taking u. p of the elongation. of the .b elt. Th e p l aci· ng of the camera s h ou ld b e sueh tha t 1·t s opera-
Ihe cowlm. g s. hould bear an. mspection do. or for the gen- .w, on d oes no t reqm· re th e neo-Ie c t of th e surve1·1 1 ance o f
erator, pernnt~ng the changmg or regulatmg of the belt the skv. 0
and the changmg of the generator. The · photographic machine should be in shelter from
'Ihe speed of tlie generator should be regulated by a oil spray and i t should not project beyond the fuselage.
governor. 'Ihe connection ·wires should be studied with It ought to be sufficiently accessible to allow hand
a view to rapid mounting on an airplane in service and d
'1 justments for loading, change of plates, or any adjust­should
not be mounted in the shop.
ing uecessary. It should be possible to do this easily
Metal fittings.- Provision must be made for attaching
t h e wires of the various devices· requiring electrical energy with hands covered with h eavy gloves, for the largest
specified hereafter: magazine used in loading the camera.
a. Wireless. The installation should take into account the location
b. Heat for the passengers. of the photographic magazines for replacement purposes
for the types which are in service.
c. Warming up the machine guns.
d. Equipment for night flying.
Installation of the wireless .- The wireless should be
installed to permit functioning in direct or in indirect
excitation by simple management of the commutators.
The antennre wh eel should be placed beside the observ­er's
seat in such fashion that i t can be wound up or un­wound
easily with the righ t hand. He should be able to
do this with ease.
'Ihe outlet tube of the antennre should be placed so tlrnt
its unwinding may be made in the same manner on all
airplanes.
The wheel should be placed outside the observer's place.
'Ihe ti·ansmitters should be secured by the aid of very
solid attaching fittings, assuring perfect rigidity during
manipulation.
Commutators and adjusting arrangements for the wire­less
should be placed in reach of the observer and should
be arranged for easy management.
The ti·ansformer and a voltage regulator should be
placed where it is sheltered from the gas vapors.
The receiving apparatus and the storage batteries
should be easily removable. They may occupy the place
of tlte photographic outfit.
Night equipment.- Landing lights should be adjustable
fore and aft by means of a rigid control managed by the
pilot.
The location of the navigating lights should be such
that the ligh ts may be quite visible to the observer and
at tlte same time may determine the exact position of tlte
airplane for neighboring airplanes. The navigation ligh ts
should be streamlined.
The storage battezies should be removable to permit
recharging the battery on the ground.
VIII. PHOTOGRAPHY ARRANGEMENTS.
Airplanes should permit the use of cameras in the condi­tions
provided for their class.
In addition to the general visibility necessary to the
management and defense of the airplane, it is necessary
that the pilot in horizontal flight can see, under the most
I X. l\fISCELLANEOUS ARRANGEMENTS .
Parachutes .-A.ll airplanes should be arranged for
receiving as many parachutes as persons. Ability to
use the parachute should be one of the first conditions
imposed for the arrangement of the interior. A placing
of the pilot analogous to that of the Salmson is not permit­ted
in a war machine.
Oxygen apparatus.- Installation of oxygen apparatus
should be provided for in a11 machines.
Cables.- Each machine should be furnished witlt a
device permitting the machine to be towed by mechanical
traction and a device permitting the t ying down of tlte
machine in case no hangars are available.
FRENCH TYPE SPECIFICATIONS.
The F rench aeronautical authorities realized late in
l919 that it was necessary to formulate a definite program
for the development of military aircraft. The delay in
working up a program was due primarily to tlte fact that
France was so stunned at the end of the World War that
it was necessary for her to remain dormant until she could
ascertain what h er futt~re military problems would be.
However, she went to work in a very logical way and
determined what kind of planes would be necessary in
order to insure proper defense. This resulted in definite
conclusions in which type specifications were draw·n -up.
The present French technical program is still based pri­marily
on these specifications.
Study and comparison of the French specifications
with our own are not only interesting but should be care­fully
considered in any revision of our requirements.
A table showing the various French t ypes with the require­ments
for each t ype follows. In addition, each type is
considered in minute detail, giving the general require­ments,
armament, fuel, equipment, and characteristics.
In these tables where t he French refer to the military
load, they mean pa~sengers, armament, and equipment.
The fuel supply is measured in hours running with the
motor turning at full speed under sea-level conditions.
20
Table of type specifica, ions.
Type. Military Hours Ceilin~. Ceiling. Speed, Speed. load . gas . theoretic. normal. ceiling. sea level. Remarks.
_ _ _ ____ , ___ -------- - - - - 1-- - -
Kilo- Kilo-
Kilo­grams
.
220-270
220-270
meters per meters p er
Pursuit: Meters.
9,000
6,500
Meters.
7, 000
4, 000
hour. hour.
C.1. __ 2}-3
2}-3
240 120 · Monoplace pursuit for higb altitudes.
c.L.·- · -·- 270 120 Monoplace pursuit for low altitudes.
Pursuit and recon­naissance:
C.Ap.2.
CAn.2. -
0bservation:
A.2. __ _
Ad.2 .. ___ _
Ab.2 ...
Bombardment:
Bp.2_·· ·-··
BS.2 .... - .­Bpr
3 .. - · · ­Bn.
2 ...
Bn.4. ·--- ---
Colonial. .. . _ .. . . __ _
400
400
450
450
350
580
no
520
940
2, 220
750
4 8, 500 7,000
4 6, 000 3,000
3 6, 000 1, 000-3, 000
3 6, 000 1, 000-3, 000
2} 4,500 1,000
7 7,500 5, 000
4 5,000 1,. 000- 2, 000
6 7, .500 5, 000
4 4, 000 2, 000
7 4, 500 2,000
6 4,500 2, 000
PURSUIT.
Monoplace pursuitfoi- high altitudes- Airplane C. 1 type.
200
190
200
200
180
190
200
210
150
150
160
General i-equirements.- This airplane should be easily
managed , very strong, very rapid in maneuvering, and
able to dive at great speed.
It is indispensable for the pilot that visibility should
be as perfect as possible as a condition of first importance
for combat and for formation.
It seems that this can be obtained either by the con­struction
of a parasol type monoplane (Morane or Gomdou
fashion), or by stagger of the wings in the biplane cellules.
In all cases it is necessary-
1. That the top plane be at the height of the pilot's eyes.
2. That a line passing through the eye of the pilot and
the leading edge of the lower plane should make at least
an angle of 15° with the vertical.
3. That the slope at the rear of the lower planes permit
the pilot to see straight down.
4. That the section of the fuselage and cowling of the
fuselage be studied to reduce the dead angle due to the
fuselage and to the motor.
5. 'That the' height of the pilot's seat be regulated and
provision be made for the pilot to turn himself easily upon
the seat.
The airplane should be furnished with a removable
armor plating protecting the pilot from the rear.
The motor should be capable of automatic starting.
Armnment.- Two rapid-fu-ing guns, synchronized, or
preferably a rapid-firing gun and an automatic cannon,
are required. 'The guns may be, at will, either 7.65 or
1 millimeter caliber; 800 cartridges per gun, 30 projec­tiles
for the cannon.
Fuel.-Tanks for three hours' fuel for the motor turning
at full speed at sea level.
To avoid excessive weight, it is suggested and preferred
to have gasoline rip panels on the bottom of tank to assure
emptying of tank in case of fire rather than leak-proof
tanks.
Equi pment. - 'Jhe airplane ehould have provision to
provide warmth for the pilot, for installation of oxygen
apparatus, Very pistol, automatic photographic apparatus,
parachute, and, eventuall y, interairplane telephones.
110 Bi place pursuit or reconuaissance.
90 Bi place pursuit and night reconnaissance.
90 Biplace, C. A., and divisional.
90 Do.
80 Armored biplace for di visional squadrons.
90 Biplace, day bombardment, long distance.
100 Biplace bombardment or attack .
100 Tri place of protection for the day bombardment.
80 Biplace. lightly loaded for dai: bombing and combat.
80 M~,!~f1~ce, heanly loaded, mght bombardment, long dis-
75
Characteristics .- Ceiling, 9,000 meters. Speed at 7,000
meters, 240 kilometers per hour. Minimum speed at sea
level at most favorable angle, with motor thTOttled, 120
kilometers per hom.
Military load of 220 kilograms in case of two machine
guns; 270 kilograms in the case of a cannon and one
machine gun.
'Ihe weight of the pilot's armor is not included. in the
useful load as listed, which comprises the pilot, machine
guns and cannon, their supports and ammunition, oxy­gen
apparatus, instruments, heating equipment, inter­airplane
telephone, Very pistol, and parachute.
·Single-seater fighte1· f 01· low altitudes-Airplane c. 1.
General requirements.-This airplane should have the
same qualities of management, or solidity, as the mono­place
C. 1, and it should offer the pilot the same visual
field.
The realization of this monoplace for low altitudes has
no special interest except that the airplane possesses,
at 4,000 meters, a considerable superiority of maneuver­ability
and speed over the monoplace C. 1 (a difference
of speed of about 15 kilometers).
Armament.- Same as for airplanes C. 1 type.
Fuel.-Same as for airplanes C. l type.
Equipment.- Same as for airplanes C. 1 type, except
the oxygen apparatus.
Characteristics.- Ceiling, 6,500 meters. Speed at 4,000
meters, 270 kilometers per hour; minimum speed at sea
level, with motor throttled and at most favorable angl_e,
120 kilometers per hom.
Military load , 220 kilograms in the case of two machine
guns or 270 kilograms in the case of a cannon and a machine
gun. The weight of the armor is not included in the
military load.
PURSUIT AND RECONNAISSANCE.
Bi plane pursuit and reconnaissance- Airplanes C. Ap. 2
type.
General requirements.- Designed specially for -evolutions
at high altitudes (7,000 meters). Visibility should be
perfect for the pilot and for the passenger. The observer,
normally seated, sb.ould see 30° forward and vertically.
\
21
Filot and passenger, at the maximum distance, should
be able to communicate by sight and voice without
aviophone.
The airplane should be capable of fast maneuvers,
easy for average flying.
machine-gun supports, airplane instruments, oxygen
apparatus, photographic apparatus, heating arrangements
and their supports, the ground glass and its support, the
interplane telephone, and the container for the Very
pistols.
The motor should be particularly reliable in order to
give the pilot the necessary confidence for distance mis­sions.
Bi place pursuit and night reconnaissance .-Aii-planes C. An.
2 type.
This airplane can be realized with motors of 500 or more
horsepower. These motors can not _be counted upon for
1920.
The motor for use, then, will be a motor of lower horse­power,
furnished with a device permitting the conserva­tion
of power at high altitudes. This will have the ad­vantage
of permitting the realization of a machine more
maneuverable, although less powerful.
The interior arrangement should be complete and very
comfortable.
The airplane will be designed for receiving, if neces­sary,
two armored seats. The tanks will be protected or
easily detachable. The airplane will have double con­trols
or provided with an easy passage from the passenger 's
eockpit to the pilot's seat.
Armament.-The tield of fire for the observer should be
free to the maximum, particularly toward the rear and
downward.
An arrangement should be provided for the installation
of a floor gun shooting underneath and to the rear.
PURSUTT TYPE.
One or two machine guns, syn­chronized,
or a cannon.
Two 1naChine guns joined to­gether,
on the tourelle, or an auto­mat
ic cannon (in no case should
such an airplane fly armed with
two cannons). Fi\·e hundred
car tridges per machine gun for­ward,
800 for the machine gun in
the rear, 300 projectiles for the can­non.
RECONNAISSANCE TYPE .
A syochronjzed gun, two ma­chine
guns, connected together, on
the tourelle, 300 cartridges each.
The forward machine guns can be either 7 .65 or 11
millimeter.
Fuel.- Tanks for four hours' fuel for the motor tmning
at full power at sea level. One-fourth of the total capacity
of gasoline will be contained in a removable tank provided
with facilities for dropping quickly.
Equiprnent.-The airplane will be arranged to provide
heat for the personnel and. eventually. the machine guns;
the installation of an oxygen apparatus for the entire crew,
an arrangement for Very pistols, and the installation of
two parachutes.
PURSUIT TYPE.
The installation of photographic
apparatus, moving picture or auto­matic.
Eventually, interairplanc tele­phones.
RECONNAISSANCE TYPE.
Installation of photographic ap­paratus,
or 50 and 120, with a min­imum
of 100 plates.
The installation of a gronnd glass
for visual reconnaissance.
Characteristics.-Ceiling, 8,500 meters. Speed at 7,000
meters, 200 kilometers per hour; minimum speed at sea
level, motor throttled and at most favorable angle, 110
kilometers per h our.
Military load, 400 kilograms.
In the military load are included only the pilot, the
observer, the parachutes, machine guns, cartridges,
General requirements.-This airplane should not be
cumbersome (maximum wing spread of about 15 meters).
It should be a very good glider , landing slowly, well
balanced, easily maneuvered, and supersensitive fore
and aft.
The visibility should be as good as possible, particularly
toward the front and downward.
The pusher type is not prohibited.
The pilot and the observer, at the maximum distance,
should be able to communicate by sight or voice without
aviophone.
The airplane should have double controls or an easy
passage from the observer's seat to the pilot's cockpit.
The motor will be furnished with an effectual silencer.
Tanks should be protected or easily detachable.
This airplane can be realized with motors o,f about 400
horsepower.
Armament.- Two or three machine guns, synchronized
(caliber 7.65 or 11), firing 2,000 cartridges per minute;
or, preferably, a machine gun and a cannon, two twin
machine guns on the tourelle, or an automatic cannon.
No airplane will be equipped with two automatic can­nons
. One thousand cartridges per forward machine gun,
800 per machine gun on the tournlle, and 30 projectiles
per cannon should be furni,shed.
Fu.el.- Tanks for four hours' fuel supply for the motor
turning at full speed at sea l evel.
Equipment.- The airplane will be arranged to provide
heat for the personnel and , even t ually , of the machine
guns; night lighting and the use of a searchlight; insta.1-
lation of two parachutes ; the installation of wireless
(sending a nd receiving) with a vie"· to regulating artillery
fire ; the use of instruments of goniometry; the installation
of bomb flares ; the installation of an arrangement for
Very pistols.
Characlerislics.-Ceiling, 6,0CO meters. Speed at 2,COO
meters, 195 kilometers per hour; speed , minimum, at sea
· level , motor throttled, at the most favorable angle, 90
kilometers per hour.
Military load, 40'.l kilograms and 450 k-ilograms if the
armament includes a cannon.
In the military load are included only the pilot and
observer, the machine guns, the cartridges, the machine­gun
supports, the airplane instruments, wireless, heating
apparatus, lighting apparatus, parachutes, and the
instruments o,f goniometry, pistols, and signal guns.
OBSERVATION.
Biplaces, C. A. and divisional.- Airplane A. 2 and Ad. 2
type.
General requirernents.-The airplane should be very
maneuverable, and controls should offer a minimum of
fatigue to pilot from sea level to 4,000 meters:
The span should not exceed 15 meters.
22
The airplane should have a very solid chassis and be
so constructed as to resist bad landings.
It should have a speed range of two to one and should
be able to take off very quickly.
The pilot and observer should be as close together as
possible and should be able to communicate by voice and
sight w~thout aviophone.
The visibility of the pilot and observer should be stud­ied
from a standpoint of ground observation when at low
altitudes.
It should have, if possible, a special adaptation of motor
for divisional squadron types.
The airplane should be designed to accommodate two
armored seats, dua,l control or passage facility from the
observer's cockpit to pilot's cockpit, rubber-covered tanks
or detachable tanks, and the control cables should be
doubled with different points of attachme1it.
This type ought to be provided with a motor of from
300 to 400 horsepower.
Armainent.-One synchronibed machine guri, two tou­relle
machine guns, one floor gun shooting underneath
and to the rear, 500 cart ridges per gun, and removable
bomb rack for 100 kilograms of bombs·.
Fllel.- Three hours' fuel at sea level.
Equipment.- The airplane should have prov1s1on tor
wireless (sending and receiving), Klaxon warning appa­ratus,
heat for the occupants and eventually of machine
guns, oxygen installation, two parachutes, two Very
pistols, and 20 Very pistol cartridges.
PHOTOGRAPHY.
AIRPLANE C. A.
Installation provision for pho­tographic
outfit, vertical and ob­lique,
26 and 50 and for photo­graphs,
vertical, or 120, minimum
of 50 exposures.
DIVISION AL AIRPLANE.
Installation provision for verti­cal
and oblique photographic out­fit
of 26 and 50, and also for instal­lation
of automatic and moving­picture
apparatus.
A folding observer's seat should be installed and also
a container for message blanks at the disposition of ob­server.
The wireless installation and photo outfit installation
should be compatible solely with the use of the wireless
with direct excitation.
At all times for other wireless arrangements it is in­dispensable
that the changing of these equipments will
not require more than three hours for two mechanics.
Characteristics.-Ceiling, 6,000 meters. Speed at 2,000
meters, 200 kilometers per hour. :Minimum speed at sea
level, at most favorable angle, with throttled engine, 90
kilometers per hour.
Military load, 450 kilograms.
In these weights are included pilot, observer, para­chutes,
machine guns, oxygen apparatus, cockpit instru­ments,
Very pistols, Very ammunition, photographic in­stallation
and supports, wireless outfit and heating outfit.
Armored two-place for divisional squadrons- Airplane
type Ab. 2.
General reqiiirements.- T ype Ab. 2 should be very ma­neuverable.
It should be capable of executing a complete
figure "eight " at 100 meters between two points 100 meters
apart without losing alt.i.tude.
It must be armored against normal shots fired at 300
meters range from underneath, behind, and from the
sides.
It is understood that all equipment, including motor,
motor accessories, radiator, and wireless, must be armored,
also gas tanks, if not installed as per _system of the Lanser
type.
All control cables should be doubled and far enough
away from one another throughout their length so as not
to be severed by one projectile.
All vital members shall be studied to diminish risk of
rupture from rifle fu-e.
The pilot and observer should be located as close to­gether
as possible and capable of communicating with
-each other by sight and voice without aviophone.
Visibility to both should be such as to permit good
ground observation at low altitudes.
The plane should have dual controls, or facility for pas­sage
of observer to pilot's cockpit.
Armament.- One synchronized machine gun, two
tourelle guns permitting of interplane combat fire or
ground fire, one floor machine gun permitting firing
underneath fuselage with good sighting, facilitating accu­rate
ground fire , 500 cartridges per gun.
Fuel.-Two and one-half hours' fuel for motor running
at full power at sea level.
Equipment.-This type should have arrangements for
wireless (receiving and sending), auditory warning appara­tus,
heat for the occupants and eventually of guns, two
Very pistols and ammunition. The comfort of the ob­server
gunner should be specially studied, as for type A. 2.
This type should permit of installation of photographic
apparatus, automatic or motion-picture ( opening to be
closed by removable armor plate) .
Characteristics .- Ceiling, 4,500 meters. Speed at 1,000
meters, 180 kilometers per hour; minimum speed at sea
level, motor throttled, at most favorable angle, 80 ki lo­meters
per hour.
Military load, 350 kilograms (armor not included) .
In this military load are included only the equipment,
machine guns, cartridges, supports and tourelles, cock­pit
instruments, Very pistols and ammunition, wireless
apparatus, heating and photographic outfits.
Coefficient of safety in static tests, the same as for air­plane
type A. 2 under the same conditions.
BOMBARDMENT.
Biplaee for day bombardment, long distance- Airplane
Bp. 2 Type.
General requirements .- This airplane should be designed
for group evolutio~s at an altitude higher than 5,000 meters.
Its speed should be little inferior to that of the biplace
pursuit planes.
The motors should be furnished with self-starters.
Being given duties of long duration to accomplish, the
pilot and observer should be comfortably installed .
A turning seat at a regulated height will be planned to
permit the observer to see the sky and the ground while
remaining seated.
The pilot and bomber, brought together as nearly as
possible, ought to be able to communicate by sight and
voice without the aviophone.
23
The airplane will carry double controls or else have
easy passage from the passenger's post to the _observer's.
The field of vision of the pilot and of the bomber will be
particularly studied for group flying, for surveillance of
the sky, and for the search for an objective. The field of
vision forward on the vertical should be 45° for the pilot
and 75° for the bomber.
Rip panels for the tanks and two armored removable
seats should be provided.
Controls should be double, with different points of
attachment.
Armament.-A machine gun, synchronized; two twin
machine guns on the tourell e; 500 cartridges per gun:
installation provided for floor machine gun, firing below
and to the rear.
Bombs.-The airplane should be able to carry 200 kilo­grams
of bombs with complete load of fuel. Besides, it
should be arranged with removable bomb racks for a weight
of projectiles corresponding to one-fourth of the fuel and
weight of the removable tanks.
The bomb racks should be able to permit the easy
change from one to the other of th.e following loads:
1. Entire load of bombs of 10 kilograms (incendiary or
fragmentation).
2. Entire load of bombs of 50, 100, or 200 kilograms.
Fuel.-Tanks for seven ·hours' fuel for the motors at full
speed at sea level, one or several tanks representing about
one-fourth of the total capaci ty, should be easily re­movable.
Equipment.-The airplane should be arranged to permit
vertical photography from 50 to 120; installation of an
automatic or moving-picture camera for vertical pho­tography
or oblique toward the rear (for photographing
the results of bombardment); heat for the pilot and pas­senger
and eventually of the machine guns; installation
of oxygen apparatus; two parachutes; and eventually of
night lighting equipment and interairplane telephone.
Characterutics .- Ceiling, 7,500 meters. Speed at 5,000
meters, 190 kilometers per hour; minimum speed at sea
level, at most favorable angle, with motor throttled, 90
kilometers per hour.
Military load, 580 kilograms.
In this military load are included only the pilot, ob­server,
machine guns, cartridges, machine-gun supports,
cockpitinstruments, bomb racks, bombs, oxygen apparatus,
parachutes, photographic and heating outfits, their sup
ports, and interairplane telephones.
Biplace bombardment and attack-Airplanes BS. 2 type.
General re,,uirements. - This airplane should not be cum­bersome
(wing spread of about 18 meters). It is not
necessarily single-motored.
It should possess strong landing gear, capable of resisting
bad landing fields.
The speed of its take-off should be sufficient for using
improvised landing fields.
The one or two engines should be equipped with self­starters.
The pilot and observer should be as near together as
possible and able to communicate by sight and voice
without aviophone.
The airplane should carry double controls or should have
easy passage from the observer's cockpit to that of the
pilot.
Visibility for the pilot and observer should be perfect
ahead and toward the ground.
Comfort and inte1iorinstallation will be specially studied.
All controls should be doubled with separate points
of attachment.
Tanks should be protected or easily detachable.
ARMOR.
BOMBARDMENT.
Two removable armored seats.
ATTACK.
Two removable armored seats,
more removable armored plates
protecting the engine underneath
and the personnel against normal
sh ots, resisting perforation at more
then 400 meters altitude.
ARMAMENT.
BOMBARDMENT.
A synchronized gun, two twin
machine guns on the tourelle, in­stallation
provided for a floor gun
firing underneath and toward the
rear, 500 cartridges per gun .
ATTACK.
For the use of the pilot: Two
machine guns arranged for easy and
effective attack on objects on the
gr0tind.
For the use of the observer:
Three machine guns permitting
effective attack on objects on the
ground, two or less of the machine
guns should permit firing in aerial
combat.
Munitions supply should permit
the execution of continuous firing
for one minute.
The field · of firing will be specially studied to permit
fu-ing toward the ground with easy aim on land objectives.
BOMBS.
BOMBARDMENT.
The airplane should be able to
carry 300 kilograms of bombs.
The bomb racks should permit
easy change from one to the other
of the following loads:
1. Entire load of bombs of 10
kilograms.
2. Entire load of bombs of 25
and f,0 h; lograms.
ATTACK.
The airplane should be able to
carry 100 kilograms of bombs, frag­mentation.
These bombs can be
released either by the pilot or the
observer.
It is possible to adapt this type of airplane to the two
different functions by providing for the installation of
equipment necessary for the two types of work.
Fuel.- Four homs' fuel for the motors turning at full
speed at sea level. One-fourth of the total capacity of
gasoline should be contained in a tank which is easily
removable. For missions of attack, this tank should be
removed.
Equipment.-The airplane should be arranged to permit
the installation of two parachutes, installation of an
apparatus for Very pistols, heat for the occupai:ts and
eventually of the machine guns, the eventual installation
of interairplane telephone and lighting outfits, automatic
camera or motion-picture camera for vertical photography
and at an angle toward the rear.
Characteristics.~ Ceiling, 5,000 meters. Speed at 2,000
meters, 200 kilometers per hour; minimum speed at sea
level, motor throttled, and at the most favorable angle,
100 kilometers per hour; time of climb to 3,000 meters,
20 minutes.
Military lo'1d, 720 kilograms (armor not included).
24
In this military load are included only the equipment,
machine guns, cartridge3, supports and tourelles, bomb
racks, view finders, cockpit instruments, Very pistols and
ammunition, heating and lighting apparatus, and inter­airplane
telephone.
It should be furnished with strong landing gear, should
have great speed of take-off from the ground in order to be
used at need on improvised landing fields.
Visibility should be perfect toward the front and below.
Pusher type motor is not prohibited.
Triplace jor protection oj day bombardment- Airplane
Bpr. 3 type.
The pilot and observer should be as close together as
possible and should be able to communicate by sight and
voice without aviophone.
General requirements.- This airplane is intended for
close protection of bombardment airplanes, type BS.2 or
Bp.2, and eventually of airplanes, type A. 2, observation.
The airplane should carry double controls or should have
easy passage from the cockpit of the observer to that of the
pilot.
It should possess the maneuverability indispensable
to an airplane which will have to sustain defemive combats.
It should have great speed of take-off for facilitating
its missions of protection.
Its armament should be very powerful, its field of fire
perfectly free. Three removable armored seats should be
provided, tanks should be protected or easily detachable.
Controls should be double with separate point of attach­ment.
The airplane should have double controls for use of one
of the observers or easy passage from the gunner's post to
that of the pilot. One of the gunners should be placed as
near as possible to the pilot (communication by voice
without aviophone) .
The motors should be furnished with automatic starters.
Armament.- Twin machine guns on the tourelle for­ward
with fi eld of fire toward the rear, firing at a
minimum of 15° above the horizontal (in line of flight);
twin machine guns on the rear tourelle: two machine
guns, twin, firing under the fmelage toward the rear, with
a window permitting aim and sight in this direction; 500
cartridges per gun.
One of the pair of machine gum can be replaced by an
automatic cannon.
This airplane will not carry bombs by reason of its armor.
The removable bomb racks, however, ought to allow a
contingent load of 250 kilograms.
Fuel.-Six hours, of which one-third is in the tanks
which are easily removed.
Equipment.-The airplane will be arranged to permit
vertical photography and oblique toward the rear with
automatic or motion-picture camera, heat for the pilot
and passengers and eventually of the machine guns, the
installation of Very pistols, three parachutes, eventually
interairplane telephones and lighting outfits.
Characteristics.-Ceiling, 7,500 meters. Speed at 5,000
meters, 210 kilometers per hour; minimum speed at sea
level, motor throttled, and at the most favorable angle,
100 kilometers per hour.
Military load, ">20 kilograms without the armor.
In this military load is included only the pilot, pas­sengers,
machine guns, cartridges, supports and tourelles,
oxygen ap.paratus, cockpit instruments, heating apparatus,
photographic outfits and their supports, parachutes and
interairplane telephones.
Biplane, lightly loaded jor day bombing and combal.- A-ir­plane
type Bn. 2.
General requirements.- This airplane should be relatively
of small bulk (wing spread of about 20 meters).
It should be a good glider, well balanced, automatically
placing i tself in descent or ascent according to the varia­tions
of the operation of the motors.
The motors should be easily managed, sure, and silenced.
Intended for bombarding unprotected targets, it should
be able to descend very low for the bombardment and to
zoom up and climb rapidly. ' .
Tanks should be protected or easily detachable.
Armament.- Two twin machine guns on the tourelle
for use of the observer; a machine gun firing below, toward
the rear; 500 cartridges per gun. The machine guns should
permit firing upon objects on the ground.
The airplane should be able to carry 500 kilograms of
bombs with four hours' fuel ; besides, it should be furnished
with removable bomb racks for a weight of projectiles cor­responding
to one-fourth of the fuel; the bomb racks should
permit the easy change from one to the other of the follow­ing
equipments:
1. Entire load of bombs of 50 kilograms each.
2. Load of bombs, half of 10 kilograms and half of 50
kilograms.
3. Load of bombs, half of 50 kilograms a~d half of 100
kilograms.
Fuel.- Tanks for four hours' fuel for the motors turning
at full speed at sea level.
Equ!pment.- The airplane should be arranged to per­mit
lighting for night and, eventually, the use of a search­light
for landing, h eat for the crew and, eventually, of the
machine guns, installation of two parachutes, use of the
apparatus of goniometry, installation of bomb flares,
installation of an arrangement foi· signaling by Very
pistols.
Characteristics.-Ceiling, 4,000 meters. Speed at 2,000
meters, 150 kilometers per hour; minimum speed at sea
level, motor throttled, and at the most favorable angle,
80 kilometers per hour.
Climb to 2,000 meters in 20 minutes.
Military load, 940 kilograms.
The military load comprises only the crew, machine
guns, cartridges, supports, tourelles, bomb racks, view
finders, cockpit instruments, heating and lighting appara­tus
and that of goniometry, Very pistols and ammunition.
Hea:vily loaded multiplace jor long-distance night bombard­ment-
Airplane Bn. 4 type.
General requirements.- Designed for carrying the greatest
load possible a distance of 200 kilometers. Mobility is a
secondary quality. The wing spread is not limited, pro­vided
the wings are easily demountable to permit the
shelter of the airplane under a hangar 26 by 28 meters.
The airplane should be equipped for four people- a
pilot, a pilot's aide, a bomber, and a mechanic. A run­way
in the fuselage should permit easy passage from one
post to another.
The airplane should be at least trimotored and should be
able to take off with one motor cut out. The motor~
should be accessible in flight.
25
It should be furnished with an effective silencer and an
au to ma tic starter.
The field of vision ought to be perfect, especially toward
the front and below.
Tanks should be protected or easily detachable.
Armamenl.- Two machine guns upon the forward
tourelle; two machine guns on the rear tourelle; two ma­chine
guns under the fuselage toward the rear, with a
window permitting sight and aim. Five hundred car­tr
idge3 per gun.
The supports of the machine guns should permit firing
at objects on the ground.
The airplane should be able to carry 1,500 kilograms of
bombs when it carries only six hours' fuel. Besides, it
should be furnished with removable bomb racks for a
weight of proj ectiles corresponding to one-fourth of the
gasoline and to the weight of the removable tanks.
The bomb racks should permit of easy change from one
to the other of the following eq uipments:
1. Entire load of bombs of 100 and 200 kilograms.
2. Load, half of bombs of 50 kilograms and half of bombs
of 100 and 200 kilograms.
3. Load with three hombs of 500 kilograms.
4. Load of one bomb of 1,000 kilograms and one bomb
of 500 kilograms.
Fuel. - Tanks for seven hours' fuel for the motors t urn­ing
at full speed at sea level ; one or several tanks, repre­senting
about one-fourth of the total capacity, should be
easily removable.
Equiprrienl .- The airplane should he arranged for per­mitting
lighting for night and the use of a searchlight for
landing; heat for the crew and, eventually, the machine
guns; installation of four parachutes and of wireless (re­ceiving
and sending); the use of apparatus of goniometry;
installation of bomb flares; and an arrangement for Very
pistols and ammunition.
Characleristics.-Ceiling, 4,500 meters. Speed at 2,000
meters, 150 kilometers per hour ; minimum speed at sea
level, motor throttled, and at most favorable angle, 80
kilometers per hour. Climb to 2,000 meters in 20 minutes.
Afilitary load, 2,220 kilograms.
In the military weight are included only the crew,
machine guns, cartridges, supports and to urell es, bomb
racks, bombs, view finders, cockpit instrument.s, h eating
and lighting outfits, wireless and goniometry, pistols and
Very pistols.
Colonial type airplane.
Genercil requiremenls.- The airplane ought to have an
easy landing and to realize a sufficient speed at the alti­tude
of use in ord er not to be troubled hy normal winds.
Its radius of action ought to be ex tensive on account of
the cost and the cl ifliculties of establishing refueling·
2. Absolute interchangeability of demountable parts
and, if possible, of part assemblies.
'1. lVfaintenance and easy repair.
4. Bulk reduced for transport (ease of assembly and dis­assembly).
5. Very solid landing gear and pneumatic ti.res resist­ing
the special conditions of temperature and humidity.
Motors can be cooled by air or by water, taking account,
in their ch oice and their mounting, of the special condi­tions
of their functioning and their presen-ation-temper­ature,
humidity, sand, etc. They should be strong, easy
to repair and maintain, and easy of access.
The airplane should be pol ymotored and should be able
to continue its mission with one motor cut out. The
motors should be very easy to start.
A1·mamenl, conlingent.- T wo machine guns, · front,
movable, fi ring downward; one machine gun, rear, firing
downward; 500 cartridges per gun.
The airplane should be equipped to carry ::lOO kilograms
of born bs of 10 kilograms each.
Fvel.- Six hours for motors at full speed at sea level.
Equipment.- The airplane should be arranged to permit
night lighting, installation of one parachute for the ob­server,
installation of wireless (sending and receiving), and
one photographic apparatus of 50.
Characteristics. - Ceiling, 4,500 meters with full load.
Speed at 2,000 meters, 160 kilometers per hour; minimum
speed at sea level, 70 kilometers per hour.
Military load, 750 kilograms.
The machine should be able to take in eight persons,
flight equipment included. A.rrangement should he
provided in consequence.
GENERAL REMARKS.
Power of.fire.- lt is well understood that the directions
given on the number of machine guns constitu ting the
armament exacted are valued only as an ind ication of the
power of fire exacted.
If a single machine gun lighter than two Lewis guns can
give the same po,Yer of fire wi th the same safety of func­tioning,
the constructor can proporn its adoption. The
unit of comparison adopted is, for the forward guns, the
Vickers; for the rear guns, the Lewis.
Armor.-The armored seats and remoYable armor plates
should be stu died in such a fashion as to obtain the max­imum
safety without smpassing a weight of 50 k ilograms
per person or per motor.
Radiators for the machine . gims.- The machine guns
intended for firing upon objects on the ground , on the air­planes
of types A. 2, BS. 2, or Bn. 2, should be proYided
with special radiators around the 1-a.rrel of the gun. per­mitting
it to fire long series of cartridges wi thout ri sl<ing the
deterioration of the gun.
stations.
1
FRENCH AERODYNAMIC STUDIES.
It should be able to be transformed quickly into a born- Aerodynamic studies have been giYen comiderable
bardment plane. more importance throughout Europe since the war. The
Its construction should he particularly looked after and French are conducting their aerodynamic experiments at
one should seek specially-- the present time in the wind tunnel at the Eiffel Tower
·1. Good preserrntion in normal conditions of tempera- and at the old St. Cyr Tunnel. Both places offer fairly
ture and of hygrometric de!!ree, eitlrnr the temperatures good facilities for the conducting of aerodynamic tests.
currently reaching 40° and 1 h ygrometric degree variant , The E iffel Tower Tunnel is well known and complete
of 30 to 35 in western Africa to 70 to 90 in the oth er colo- 1 description of the St. Cyr Tunnel is available among om
nies. , technical files.
26
A new aerodynamic station is being constructed at Issy
des Moulineux, which is located on the outskirts of Paris.
The entire station is constructed of bri,ck and steel and
will have adequate facilities for the conducting of aero­dymanic
tests and all kinds of experimental work. Pro­vision
has also been made to have a flying field available
in the near future, adjoining this station.
A large headquarters, hangars, engine test stands, dy­namometers,
and buildings to house every known device
for testing materials, have been constructed. However,
by far the most interesting building on this station is the
one which houses the new wind tunnel.
This tunnel is located in a building of brick and steel
about 210 feet long and 100 feet wide. Plenty of windows
and large skylights have been incorporated in the con­struction
in order to have plenty of light. A large pit.
about 8 feet deep, lined with cement, takes up the entire
floor space of the building, with the exception of the gang­ways
along the sides and ends. Next to this building is
anoth_er one of similar construction, built to house the
engines that will furnish the electrical energy to supply
the tunnel.
The tunnel itself is of the Eiffel type and is entirely
constructed of reinforced concrete. It was built in accord­ance
with the design of the aerodynamic section of the
French technical service and was constructed by the com­pany
of which Mr. Caquot, formerly of the technical
section, is the head. The tunnel is supported by two
huge concrete wall:;; running longitudinally along the en­tire
length of the tunnel. This leaves a free air space
under the tunnel.
The entrance nozzle is set high up from the floor and
back from the walls of the building. The section of the
outer walls of the collectors has been made square instead
of circular, and of a width equal in diameter to the front
end of the collector. This permits the outer walls of the
collector to be parallel to the walls and floor of the room
and eliminates any break of contour caused by the experi­mental
chamber. Aft of the experimental chamber the
outer walls are gradually faired into the diffuser.
The diameter of the tunnel is 3 meters at the throat
and 7 meters at the propeller end. It is to be driven by a
six-bladed propeller. The section of each blade is to be
exactly analogous to the arc of a circle. It will be possible
to vary the pitch of the blades of the propeller, but this
can not be done while it is in motion. The propeller
will be driven direct by a 1,000-horsepower electric
motor which will permit a speed of appi-oximately 260
feet per second to be attained.
Behind the diffuser is a concrete stand for the motor.
In order to change the direction of the air lea0,ing the
diffuser, the two forward faces of the stand are cmved
in the plane. It is proposed to continue these curv~s
upward and outward by wooden partitions.
Entrance into the experimental chamber is gained by
means of a passage with a staircase inside of one of the
supporting walls of the tunnel. 'lhe passage is equipped
with two steel doors to insme an air lock. 'lhe experi­mental
chamber itself is very large, being roughly
cubical, about 20 feet to a side. The diffuser ends and
the collector project into the experimental chamber.
'lhe only natural light in the chamber is that which
comes through the collector.
The floor is equipped with a sq uare trap closed by a
movable platform. When it is desired to work with large
models the movement of a lever lowers the platform
sufficiently for it to come into contact with a track mounted
on the inner faces of the two longitudinal