Technical bulletin no. 43. Development of military aircraft material for United States Army Air Service under supervision of Engineering Division

              ,1 7 //
IAL TO. -- LI ~~.,_ ..
AIR SERVICE INFORMATION CIRCULAR
VOLUME V
(AVIATION AND AEROSTATION)
BY DIRECTION OF CHIEF OF AIR SERVICE
SECOND QUARTER - 1925
TECHNICAL BULLETIN
No. 43
NUMBER 485
DEVELOPMENT OF MILITARY AIRCRAFT MATERIAL FOR UNITED STATES
ARMY AIR SERVICE UNDER SUPERVISION OF ENGINEERING DIVISION.
Prepared and Published
By Direction of the Chief of Air Service
and under the supervision of
JOHN F . CURRY, Major, A. S .,
Chief of Engine ering Division.
McCook Field 7 - 2 - 25-1 M
CONFIDENTIAL
The information contained herein is confidential and therefore
must not be republished, either as a whole or in part, without
express permission of the Chief of Air Service, U. S. Army.
CONTENTS
AIRCRAFT DEVELOPMENT
AIRPLANES
Curtiss P-1 _____________ ____ ----------------- ---------- --------------- - --- ------------ ------------ ·-- ·- -------- 7
All-Metal Observation Airplane, Model X0-6 ____ ___ --- --- -- --- -- --------- -·-- ··-·---- -·------·---- ------ ________ 7
Design Competition for Night Observation Airplane_ _______ _______ _______ ___ _____ __ _________ ___ ____ 8
Huff-Daland XLB-1 -------- ------ -- ------- ----- -- ------------------ ----- ---- -- -- ----------- ---- --- -- -·-- --- ---- ------- ------- ·---- - 9
Design Competition for Heavy Bombardment Airplane ---- -------------- --- -------- ------------ -- --·---· 10
Heavy Bombardment Monoplane Proposed ---· -- ------ --------- ------------- -- ----- -- ------ ------- ----- -- ------ ----- 10
Douglas C-1 Transport --------- -- -- --------- ---------------- ----------- ------- ---- --- -- ----- ----- ---- ------ --------------- 10
New Racers for 1925 Pulitzer ______ __ _____ --- ------------------ --- ··-----------·--- ---- - --- ----·· ····· ·--· -----------· 11
Brakes for Airplanes __ ---····--··------- --·- -- ··-·-- ·-·· ··-·- -·----· -- ------ -- ·· ··· ····--··---- -·-· --- ----·--·-------- ·--- 13
AIRSHIPS AND BALLOONS.
TIS-1 Airship _______ ······ ······· --------------- ----- --------- 14
200-Foot Mooring Mast for Scott Field___________________ --------------·- ---- - ----------- ---- -·- 14
New Gas Cylinder Cleaning and Painting Machine ------- -- ------- ______ --- ---- -------------------- ------- - 14
ARMAMENT.
Extemal Bomb Hoist, Type E-1 __ --- -- -- -- ---------- --- --------- ------ ---------- ------- -------------·-- ·-- ·----- 15
New Type B-5 Bomb Shackle to Replace Type B-4 ___ -------------···-- -- - ---- ----- --------·- 17
Bomb Rack for 4,000-lb. Bomb Ready for Service Test____________ --- ---------------------------- 18
Pyralin Beads for Gun Sights __ __ _____ ---- ------- ----- ----- -------··-··-·-- ----- ---·- ··-·--- -----·--- 18
EQUIPMENT
Visual Indicator for Radio Beacon Signals ____ _____ _ 18
Incandescent Beacons and Landing Lights ______ __ _ -----·-----·--- --- -- ·-- ·----------- --- ---··-- -- ---- ----- 18
Night Aerial Photography by Flashlight ______________ --- --- -------------
"Quick-Work" Photogrljlphy ----- --------------··--- ·--· --- -
New Mount for T-1 and. T-2 Cameras ---··-· -·-·--·
New View Finder, Type A-2 ------ --- --- ------ -·------- ------- ­Photographic
Equipment on DH4M-2P Airplanes _
POWER PLANTS
19
19
-- ----- 19
20
20
High Speed Engine Development ---- --- ------------ -------- ----- ------··--·---· --- --------------·----- ·--·- -·-- ---· 20
Three Air-Cooled Liberty Engines on Order__ __ --- ---- ·· --·--·-··- 20
To Build 1200-h. p. Air-Cooled "X" Type Engine _ ---- ·----- --- -------- ---· - __ __ -- ---- --- --- ---- --------- -----· 21
RESEARCH AND EXPERIMENT.
RESUME' OF ENGINEERING DIVISION SERIAL REPORTS.
Analyzing and Predicting Airplane Performance_
Stress Analysis of Phillips' "Alouette" Airplane _ ----· --·------------ ----------------··· ··---·-
Torsional Test of Elias XNBS-3 Fuselage ____________ --- ---- ------- ·------------ -- -- ---------------
Desig!l of Plywood Webs for Box Beams _______________ -----· ----------- ·-- ·- -------- ·----- -·----·-- ·-----·
22
22
22
23
C 0 N T E N T S - (Cont'd)
Study of Wing Weights ···· ··········---· ·-- -----··------- -- ------------------- ---- ------- ---- --·-- -- ------ -- ------ --- --- 23
Effect of Sweep Back and Sweep Forward on an AirfoiL .. ·- ··---· ··-- ----· ·· ·--- ·-------· ··----- ---- ------- 23
Airplane Design -- -- ---- ---------·---- ---- ---- --- -------------- ----- ------------------- ----------- --- ----- -- ------ ---- ---- ---- ---·----·-·· 23
Static Tests Conducted at the Engineer ing Division .............. ...... .. ··· ··-·····················-···· ····· 23
\Vind Tunnel Tests ·····-··-······ ·· ·······----··-- -- ------ ----· ----- --·-- -- ---- -- --- --- ----------------·--------------- -- -------- --- ---- 24
Test of Oxygen Regulator, Prouty Type __ __ ___ _____________________ ______ ___ __________ ___ ____ ____ ___ _____ _____ ___ ____ 24
Test of Cauter Gasoline Gage ----- -- --·----- -- ·-·-- --- ------ -- -·---- ··---·-···· ---- ---- ----· ··----- -·---·-- ---- ---------- -- ·-- 24
Method of Reducing Flight Test Data to Standard Air ____ ____ ___________________________ _____ ______ ___ _______ 24
P erformance Test s -·- ·····-----·-- --··-·- --·-·---- ---· ··----·-·--- --- -·-- ----· ------· -··--- ---------·---·------- ---- ·--------- -- ------- 24
Spoke Lacing on Airplane Wheels .............. ____ ------- -·--- ------------------- ---- -------· ----· --- --· --·-- ---· -·------·-- 25
Clogging of Fuel Strainers ·--·-----------·--- --- ··--- ---··-----· -------··- -- --- --------- --- --- --·--· ---·------· ---·----- -·-··-·· -- 25
Instructions for Standard Engine Test and Report (Revised) ·-----·-·- ---- ·------ -· ------ -- ---- -- -- -- - 25
Test of "Boyce-ite" Fuel ----- -- --- ------ --- -- -- --- ------ ---· -- --- ------- -· ------ ---·--- --- -- ----- ---- -- --- -- -- ------- --- --------- -·- 26
P erformance of P ackard lA-1237 Engine with Modified Manifolds __ __ __ ___ ___________________ ____ 26
P erformance of Str.omberg NA-U6 Carburetor on Wr ight "H" Engine ....... -- ··-----·-·------·-- 26
Best Ra diator Location for Maximum Speed -- ---· -- --- -------- --· -· --- ----- -- -------- --··· ---- --·- ---- ---- --- ------ 27
Endurance Test of Liberty Engine E quipped with E xperimental P arts ______ -- ·- ----- ·--· - 27
INVESTIGATION OF MATERIALS.
Investigation of Br itish Doping Scheme_____ __ ____________ ---- -·--- -- ------ -- --·····- -·--· ·····-· 27
Reliability of Welds ·· ·-------·-- -------- -- ···- -- -----· ---- ----- -- ----- ---- -···- -- ---------·-------------------------·-- ---- -- ------ 27
Protective Coatings for Steel --·--------·--- -·---- ·--·- ------· ----------------·- ·--·-·-- -- ---- ---- --- ·-- 28
Universal Cup Grease for Aircraft ---- -- --·--------- -- --- --··- ---·- ·- --- --·----- ··--- --- --- --- ----- -----· ------··- 28
NEW BOOKS AND DOCUMENTS
Documents Added to Technical Files Dur.ing Second Quar t er, 1925 .. --·--·-- ------ 29
LIST OF ILLUSTRATIONS
Three New Types of Airplanes Under Test at Division ________ --- ----·-···---·· ·-· ····--··-··--- ·---· -·-- 6
General Arrangement of Army-Curtiss Racer R3C-L _____ __ --------- ------- --- -- -- ·-·· -- -- -·----- -- ---·-- -- 12
Hoisting a 2,000-lb. Bomb with Type E-1 Bomb Hoist Units ___ -- ----·------ -- -------·---·- ···---·-----·- 15
External Bomb Hoist, Type E -1 ---- -- ---------------- --·-·--------- -- -- --- -·-·- -- -------- -- --- --------- ----·-- ·-------------·-- 16
Type B-5 Bomb Shackle -------·----------------------------·-·--·----· -·-·-·-- -·-·- -·-- -- ----- ----- -- -·-·-··--------------·--·----· 17
6 T E C H N I C A L B U L L E T I N N o. 43
THREE NEW TYPES OF AIRPLANES UNDER TEST AT DIVISION.
Huff-Dalan<l Bomber XLB-1 (above) Curtiss Pursuit P-1 (center) Douglas Tra n s port C-1 (below)
(Des criptions of these airplanes are given on pages 7. 9 and 10)
AIRCRAFT DEVELOPMENT
ON ENGINEERING DIVISION PROGRAM
AIRPLANES
Curtiss P-1.
A new pursuit airplane, Mode] P-1. has been delivered by the Curti ss Aeroplane & l'vTotor
Company. Inc., Gard en City, N. Y., under produ ction contract. This airplane is reproduced from
the experimental XP\i\1-813 which crashed durin g combat maneuvers at McCook Field last N[arch
-see page 14. Tccllllical Bullcti 11 No . 42.
The P-1 may be readily di stingui shed from the standard P\V-8 pursuit by its tapered wings
and tunnel type radiator. One will recall that thePvV-8 design incorporates a double bay, wire
braced bip lane cellule with straight wings of Curti ss "Sixty-two" airfoil section and surface radi­ators.
whereas the new design utili zes a single bay biplane construction with tapered wings of
Clark "Y" section and a tunnel type radiator suspended from the fu selage beneath the engine. The
internal to nstruction of the wings also differs in these airplan es. In the new P-1 the upper
wing forms one continuous panel built about two spruce box type spars which taper outboard.
The lower wing consists of two smaller panels of similar construction, bolted directly to the hinges
in the lower fu selage longerons. Both wings a re fabric covered and taper in chord and span.
The wing construction on the PW-8 is of the mu! ti-spar type with two-ply spruce planking for the
covering. On both airplanes the aileron structure is of metal with fabric fo r the covering. steel
being used on the P-1 and duralumin on the P\ i\1 - 8. The P-1 aileron is composed of a channel sec­tion
hinge spar supporting tapered channel ribs and a flattened tube trailing edge. the whole struc­ture
resembling a \ i\'a rren truss held together by ri vets.
Among the numerous refinements which cot~ tributed to the noteworthy increase in co ntrol­ability
and maneuverability of thi s airplane over previous models as observed in preliminary fli ght
tests are the reYised tail surfaces. T hese include the use of a balanced rudder sirnila.r to that used
on the original PvV-8, an increase in the up movement of th e elevator to thirty-five degrees. five
more than on the XP\i\1 -8B, and a more rounded leading edge on the stabili zer.
P rior to performance tests which are now in progress a set of P-1 wings were static tested ar
the DiYision and found satisfactory for the vario us conditions of flight.
On the same contract for ten production P-1 airplanes is an order for fi ve P-2s, a pursuit air­plane
of the same design as the P -l except for the power plant . which in the P -2 is a Curti ss
V-1400 engine of 500 h. p. at 2100 r. p. m. The P-1 uses a standard Curti ss D-12 engine. By
subsequent agreement one of the fi ve P-2 airplar. es will be modified to accommodate the new l\1oclel
R-1454 ni ne-cylinder air-cooled radial engine of 400 horsepower which is also under development
by the Curtiss Company. This airplane will be designated Model X P-3 and used for the purpose
of determining the adaptability of this engine for air-cooled pursuit purposes.
The general cha racteri stics of the Curti ss P- 1 are as follows:
Overall span .. ..... ... ........................... . .......... 31 f t. 7 in .
Overall length ....... .... .. .... . .. .. . . . . ..... ... . ..... ..... .. 22 ft. 10 in .
nvera ll height ... . . .. . .... . .. .. ......... . .... . .......... . . . .. 8 ft. 60 in .
Supporting area .... ... . .... . ........... . .. . ....... .. . ... . . . . 250 sq. ft.
Weight, fully loaclecl . .. . . . .. .. ..... . ..... ... .... ... . .... . .. . . . 2846 lbs.
Useful load . ...... . .. .. . . . . .. ... ... . .. .. .. . ........ .. .. .... . 788 lbs.
AU-Metal Observation Airplane, Model X0-6.
F i\'e experimental observation airplanes to b e designated l\Iodel X0-6 are under develop­ment
for the Army Air Service by the Thornas-1\forse Aircraft Corporation, Ithaca, N. Y . T hese
airplanes will be built entirel y of metal and of a type of construction with which this firm has had
8 T E C H N I C A L B U L L E T I N N o. 43
several years experience. The design incorpora tes a standardi zed type of two-seater observation
airplane similar to the Douglas 0 -2, to be built around a standard Liberty engine. Among the
special features will be the use of an oleo shoc k-absorbing chassis in place of the conventional
elastic cord type and the disposition of the fue I, the main supply of which will be carried in
two 60-gallon droppable tanks in the lower win g . F or emergency and increased range of opera­tion
provision is made for the installation of a 40- gallon auxiliary fuel tank in the fuselage forward
of the pilot's cockpit and a 10-gallon reserve gravity tank in the upper wing . T he design also pro­vides
for the in stallation of night-flying equipment . external bomb racks and machine guns in
addition of the regular observation complement.
The static test model required under the con tract is about completed, hut the deli very of the
fir st flight test. art icle is not scheduled until J anuary, 1926.
Design Competition for Night Observation Airplane.
On the fourth of May, 1925 , designs and bids for the development of an experimental
night observation airplane around a 50)-11. p. wa ter-cooled engine were received J,y the Army Air
Service at McCook F ield from seven aircraft designer s and manufacturers in response to Circul ar
P roposal E-2529 issued to the industry last F ebrua ry, as fo llows:
Buhl-Verville Aircraft Company, Detroit, M.ichigan.
Cox-Klemin Aircraft Corporation, Baldwin, N. Y.
The Douglas Company, Santa Monica, Cali fornia.
G. Elias & Bro., Inc., Buffalo, N. Y.
C. Ward Hall , Incorporated, New York, N. Y.
Kirkham Products Company, Garden Ci ty, N. Y.
Lawson Aircraft Company, New York, N. Y.
In this contest the selection of a suirnble des ign was based upon three important reqmsites­maximum
visibility, slow landing speed and maxi mum sa fety for crew"-as exemplified iu a pusher
. type airplane designed around a Curtiss V-1400 or P ackard l A-1 500 engine. All of the com­peting
designs involved an airplane utilizing a central nacelle for crew and power plant, the main
differences lying in the method of supporting the tail surfaces . In four in stances this constituted a
twin fu selage con struction, and in the remaining three a tail boom trussing. One of the designs
call ed for an all-metal construction but the oth ers proposed a wood and metal construction along
conventional lines. T he design finally ~el ecte d as possessing the best combination of the above
requisites, plus general performance, flying qualities, arrangement, structure, maintenance and ease
of production was that submitted by the Douglas Company, \.vhich firm was subsequentl y awarded
the contract.
In brief the Douglas design incorporates a co nventional two bay, externally braced biplane con·
struction with central nacelle for crew and power plant and converging tail booms supporting the
tail surfaces. The wings are of tl:e constant chord type, built in sections, with fuel tanks placed
in the stubs. The central nacelle projects well forward of the leading edge affording both pilot
and observer in the nose the greatest possible visibility. T he power plant, a Curti ss V-1400 eugine,
is mounted as a pusher in an ao~es sibl e location at rear of the nacelle where suffic ient space is pro­vided
for propeller to clear wing and tail booms. The radiators are unusually accessible for repair,
being mounted on inclined struts which extend from the lower wing stubs to each side of the
nacelle. The airplane is supported by a di vide<l ax le chassis attached to the lower wing stubs ·.veil
out from the nacelle. Saf ety in night landing is further augmented by means of an aux ilia ry
single-wheeled oleo gear mounted under the r:ose.
Under the contract the Douglas Company i$ to build only certain parts of an airplane, included
as follows : a wind tunnel model provided with adjustable wing flaps ; a mock-up of nacelle show
ing arrangement of cockpits, engine in stallation and wing stubs and in addition two detachable
nose sections, one for observation and the other fo r t raining ; part s of the wing structure fo r static
test; a complete nacelle structure including both types of nose sections, fire wall and engine cowl­ing
but withont covering or equipment; and a set of tail booms complete from point of attach­ment
at wing to their termination at the tail post. In event further development is warranted upon
completion of this contract, the government may by option require the contractor .to build a com­plete
airplane using the nacelle and tail boom structures just mentioned.
In order to in sure t he development of a "ati sfactory airplane for night observation purposes,
the per forma nce requirements for this type of air plane were placed high. A maximum speed of
J
AIRCRAFT DEVELOPlVIENT 9 .
125 miles per hour coupled with a high degree of maneuverabi lity was considered necessary for
protection against enemy aircraft and hostile searchlights, a high rate of climb of 1300 feet per
minute for quick get-away from small field s, and a very slow landing speed for safety in making
night landings in strange territory. These requirements were based upon conclusions reached after
several year s' consideration of this project whost> actual development had until now been held in
abeyance under the urgency of other projects.
Huff-Daland XLB-1.
T he advent of the XLB-1 introduces a new t ype of single engined light bombardment air­plane
whose inherent advantages as expressed in simplified construction, increased performance
and greater load-carrying ability render it superior . to the conventional multiple engined type in
present use. This airplane was developed by H uff, Dalancl & Company, Ogdensburg, . Y., under
experimental contract from a design selected in the Light Bombardment Airplane Competition of
April , 1924.
So far the XLB-1 is the largest single engin ed airplane of its type ever built in this country.
It measures 66 ft. 6 in. in span, 46 ft. 2 in. in length and 14 ft. 11 in. in height and weighs 10,014
pounds fully loaded, of which 4,632 pounds constitute useful load. A crew of three is accommo­dated;
pilot and bomber in the front cockpit and gunner in the rea r. The airplane is equipped
for night-flying, with electric landing lights strea mlined in the wing tip. Provision is also made
for the installation of both external and internal bomb racks and fi ve fl exible machine guns.
The normal bomb load aggregates 1254 pounds which is the same as that carried by the present
standard twin-engined bomber.
The design is characterized by an unusually large single hay biplane cellule supporting a rela­ti
vely long fuselage with the engine mounted in the nose. T he wings are sectional. They consist
of four tapered outboard panels braced in the bay by two single encl struts and streamline wires
extending to their points of attachment, a straig ht upper center section housing two gravity tanks
containing the entire fuel supply, and two lower wing butts beneath which incliviclual oleo tripod
type chasses spread outward from the fuselage. T he central portion of the cellule is braced by six
inclined struts extending from upper fu selage Ion gerons to both wings. There is no stagger or
dihedral except that fo rm.eel by the taper of the underside of the wing.
0~1e of the features is the fu selage con struction. This incorporates a P ratt trussed structure
built of welded chrome-molybdenum steel tube with rigid diagonals. The engine mount is detach­able,
and clue to the geared engine arrangement it elevates the propeller axis nine feet from the
ground when the airplane is in flying position the rehy pro viding ample clearance for swinging a 16-
f oot propeller.
Both chassis and tail skid are equipped with oleo shock-absorbing units embodying oil cylinders
with spring return. Ordinarily 44"x10" wheels are used on this airplane. In order to provide
suffic ient clearance for carrying the 4.000-lh. born b beneath the fu selage, over length axles with
special bushings have been provided to accommocl ate the in stallation of 54"x 12" wheels, ihe same
size as used on the Barling Bomber.
As originally designed, a \!\fright T-3 engine was to have been used in this airplane. Later
when the new Packard Model l A-2500 engine of 800 horsepower became available, a change in
power plant was made to increase performance. The Packard engine is fitted with a two-to-one
reduction gear which gives a propeller speed of 1000 revolutions per minute at full throttle. Fuel
is supplied by gravity from two 175-gallon tank s in the upper wings. One tank is partitioned in
order to provide a 30-gallon reserve supply for e mergencies. Cooling is effected by means of one
free air radiator suspended beneath the engine.
In preliminary flight trials with normal fuel and bomb loads, the XLB-1 attained an indicated
high speed of 124.S miles ·per hour in level flight at ground and a service ceiling of 15,550 feet.
This performance, however, is very preliminary a ncl should not be taken as final inasmuch as the
standard performance tests have not yet been ma cle. Some estimations have also been made as to
the probable performance of this airplane with present fuel load, four 600-lb. bombs and a crew
of fi ve which brings the gross weight up to 11 ,918 pounds. W ith this increased load a high speed
of 124 miles per hour at ground ancl a service ceiling of 12,500 feet are anticipated ._ The cruising
range under these conditions is calculated at 420 miles, whereas with an all fuel load this range is
placed at 1950 miles.
10 T E C H N I C A L B U L L E T I N N o. 4:)
Design Competition for Heavy Bombardment Airplane.
The design competition for a heavy bombardment airplane, held by the Army Air Service at
McCook Field on l\farch 11 , 1925, resulted in the selection of a design submitted by Huff, Daland
& Company, Inc., Ogdensburg, N. Y., one of the participating firm s. Immediately following the
award, an experimental contract was placed with this firm for the development of a heavy bomber
in accordance with the selected design, to he designated Model XHB-1.
Designs submitted in this competition were of two types, biplanes and monoplanes. The
relative advisability of adopting either type of co nstruction depended largely upon its present stage
of development, its successful appli cation in the past, and its possibilities of immediate production.
Judged on this hasis. the cle\·elopment of a biplan e capabl e of carrying a 4,000-lb. bomb afforded
an easy and natural transition from existing and proven types of construction and a quicker means
of getting this type of airplane into production th an would be possible with a monoplane con­struction
of this magnitude. Of the biplane des igns H uff-Daland's proved most promising, and in
consideration of this firm's recent experience with the XLB-1 light bomber, just corpp1eted, ii was
decided to award them the contract.
The design selected incorporates a large sin gle-engined , four- seater airplane of binlane con­struction
quite similar to the XLB-1. T he cellu le is a double bay, externally braced structure
composed of semi-thick sectional wings with an u sually large gap. The fuselage, roomy and almost
square in cro~s section, supports a single 800 h. p. geared Packard engine high in the nose. Direct­ly
behind the engine is placed a large double cockpit for pilot and observer. Below this is another
cockpit for the bomber so p laced as to give him an unobstructed view of the ground and easy com­munication
with the pilot. T he bomb compartme nt extends full length of the wing chord and is
of :adequate proportions to accommodate bomb loads in excess of four thousand pounds on either
internal or external racks. The rear portion of the fu selage is occupied by the gunner and other
incidental equipment with ample room for the operation of both ring mount and fl oor guns. An
extra wide landing chassis and conventional tail structure complete the layout.
The contract calls for the developmen t of only the principal parts of an airplane suff icient to
determine its aerodynamical qualities, di spcsition of equipment and structural rigidity. This in­cludes
the construction of a wind tunnel model made to scale ; a mock-up of the f uselage showing
layout of front portion as far back as rear cockpit, with wing stubs attached: and ce r~a in par ts
of the structure for static test, iixlmfo1g one complete upper wing (without ailerons) on one side
of fu selage. There is al so included in the con tract one set of covered wings complete v, ith
ailerons and interplane bracing. \Vithi11 a specified time after completion of this contr;1ct, the
government may by option require the crmstruction of one complete airplane utili zing the set of
wings previously mentioned. P erforniance specifications for this type of airplane require a mi ni­mum
high speed of 100 miles per hour at sea-level, a minimum rate of climb of 500 feet per 111i1111te
at ground, and a ser vice ceiling of not ie:'is than 10,000 feet.
Heavy Bombardment Monoplane Proposed.
In the belief that the eventual bombing plane may be of the monoplane type. the Engineering
Division has prepared specifications for the experimental development of a heavy bombardment
monoplane to he built around the recently concei ved 1200-h. p .. air-cooled engine (see page 21 in
this issue). T he success of the project depends entirely upon the design of a wing structure of suf­fi
cient rigidity to withstand torsional defl ection in flight, a problem requiring extensive research
and experimentation. The proposed airplane is to be capable of carrying a crew of four , a normal
bomb load of 5,700 pounds :rncl enough fuel for eight hours Hight at 10.000 feet , in addition to
the necessary navigating equipment and defen sive ordnance.
The a hove requirements have been embodied jn a circular recent] y issued tu the aircraft ii; -
dustry by the Army Air Service.
Douglas C-1 Transport.
A new transport or cargo-carrying airplane, designated I\·fodel C-1 , has been developed for the
Army Air Ser vice by the Douglas Company. Santa Monica ." Ca.lifornia, under a contract for .nine
airplanes awarded in November, 1924. This airplane is designed around a standard Liberty en­gine
to carry two pilots, one for relief , in a forward exposed cockpit and six passengers or equiva­lent
load in an en d osed cabin occupying the central portion of the fu selage. It has made a favor­abl
e showing in the performance tests recently co nducted at McCook Field.
AIRCRAF T DEVELOP~ENT 11
In general outlines, the C-1 follows the sim pie characteristic design used by Douglas in the
X0-2 observation airplane described in Technical Bulletin 1\T o. 41 except that the transport is larger
overall and has a differently a rranged fu selage. The design follows a standard type of construc­tion,
easy to produce and maintain , and incorporates a single bay, wire braced cellule composed of
semi-thick symmetrical wing panels, a steel tube fuselage, conventional tail surfaces and a wide
tread split-axle type chassis. The main fuel supply is carried in the lower wing stubs.
The fundamental feature of the design is the arrangement of the fu selage to accommodate the
transportation of either passengers or freight. In this arrangement the two pilots are placed side
by side in a wide cockpit behind the engine in front of the leading edge, a position affording un­usually
good Yision for side by side seating. The control s are mounted on the left side only. relief
in piloting being affected by an interchange of pilots. The passenger cabin which occupies the
main portion of the fuselage is entered thru side doors or thru a small opening from the pilots'
cockpit. Comfortable accommodations are provided for six persons when seated, but the cabin
is not of sufficient height to permit them to stand erect or walk about. Vision from the six
circular windows is somewhat obscured by the lower wing. I3y removing the seats and furnish·
ings, freight and other equipment may be carri ed.
The airplane has an overall span of 56 ft. 7 in. and a chord of 7 ft . 6 in ., giving a total sup­porting
surface of 805.16 square feet. The over all length and height are 35 ft. 4 in. and 14 ft. re­spectively.
The wings are of Clark "Y" section . set at a gap of 8 ft. There is no stagger. Fully
loaded it weighs 6,464 lbs .. of which 2,607 lbs. constitute usef ul load. P reliminary performance
with a 10-foot metal propeller indicated a high speed of 121 miles per hour and service ceiling of
13,800 feet.
In view of the excellent flying qualities displayed in the initial tests it is believed that this air­plane
is admirably adapted for use as a flying labo ratory fo r photographic or other experimental
projects, or as an aerial ambulance.
New Racers for 1925 Pulitzer.
For participation in the annual P ulitzer con test at ~1itchel Field in October, the Army and
Navy air services have united in developing a new racing airplane to he known as Model R3C-1.
This machine has been designed and built about the new V-1400 engine by the Curtiss Aeroplane
& Motor Company, Inc., Garden City, N. Y .. under a Navy contract. In all, four airplanes have
been constructed, one for static test and three for flight. Of the latter the Army receives one and
the Navy two, the second Navy 'plane being held in reserve. The machines used by the Army and
Navy in the Pulitzer race will be identica l in all respects.
In general appearance the new racer resembles the Navy-Curtiss R2C-1 , winner of the 1923
Pulitzer classic. It is of practically the same dimensions, the differentiating features compri '.>ing a
new power plant, steel tube engine mounting and a new airfoil section . As a landplane the de­signed
speed is placed at not less than 255 miles per hour-a considerable advance over the previous
racer. As a seaplan e a performance of 240 mil es per hour is anticipated.
The R 3C-1 is a single seater biplane of wo od construction built around the Curti ss V-1400
engine. The structure incorporates a monocoque type plywood f u ~e l age with steel tube engine
mounting supportecl by a single l:ay externally braced cellule of double camber uni form chord
wings and a straight axle chassis fitted with sho ck-absorbing wheels. All fixed surfaces are
covered with plywood, whereas the movable sur faces are fahric-coYered metal structures. Both
upper a11d lower wings are equippd with surface type radiators.
The wings are attached to the fuselage betw een the fourth and Ii fth bulkheads in such a man­ner
that the upper is level with the top of the fuse I age. T his permits the pilot to see over it. In
the bay interplane bracing is provided hy a ~ingle wooden strut. two single fl ying wires and one
single landing wire, the front fl ying wire being attached to the chassis. The panels are covered
with two-ply spruce planh'"ing. 3/ 32 of an inch thick, the plies running 45 degrees to each other and
22~;'.; degrees to the major ax is of the wing. ln the upper panel there a re two main box spars of
spruce, front and rear, three intermediate spars of channel section and one small rectangular bean~
in the rear of the main rear spar where<c<S in the lower panel there is only one main box spar with
three minor spars placed about it, one in front and two in rear. All of the wing ribs are of spruce.
built-in and secured to the spars by corner blocks. Lightening holes are provided in all ribs ex­cept
at the outer strut and hinge points where the ribs are so lid. No drag bracing- is necessary as
this is taken by the covering.
12 T E C H N I C A L B U L L E T I N N o. 43
The aileron is placed in the outer traiiing edge of each wing panel. It is a metal structure.
covered with fabric, consisting of a steel torque tube or hinge spar supporting duralumin ribs of
channel section. Actuation of the snrface is obtained by means of this torque tube which con­nects
with a control tube extending it:side the wing to the rod and gear operating mechani~m in
the cockpit.
The tail group is fixed to the fuselage ;:is a cantilever and therefore requires no external brac­ing.
The movable surfaces, ele\·ator and rudd er, are of metal construction similar to that n:>ed
in the aileron whereas the fixed surfaces, tin and stabilizer, follow the type of wood construction
used in the wing. The surfaces are of the ur.bal anced type.
The fuselage is a beautifully streaml ined monocoque structure so necessary in this typ~ of air­plane.
In consists of a shell or skin formed by two layers of spruce planking laid 45 degrees to the
longitudinal axis and 90 degrees to each other and glued together. Rigidity is provided by four
conventionally arranged ash longerons and seven transverse multi-ply birch bulkheads. The new
feature in this racer is the engine mounting which is made of welded steel tube. In the R2C-l
racer, this was of wood. The cockpit is fitted with stick and pedal type controls and a seat o t
sufficient proportions to accommodate a back type parachute.
Suspended from the engine mount is the ch assis, a triangular frame with its apex toward
the mount and its lower side horizontal to form a straight axle carrying two shock-absorbiug wheels
at its extremities. The chassis is rigidly braced latera1ly by the two lift wires from the upper wing
and longitudinally by two brace wires dropped from the front and rear ends of each engine
bearer to the axle. The faired portion between the wheels which are 54 inches apart gives an ad­ditional
supporting surface, five square feet in area. To complete the landing gear a hickory tail
skid made up of leaves like a spring is so fulcrumed beneath the tail post that the steel shoe at its
lower end is projected far enough under the rudd er to protect the btter in landi ng.
~-=#~~\~
4C!"
CURTISS RACER, MODEL R3C-1
Characteristics
Overall span _
Overall length
Overall h eig ht _
Airfoil section __ _
Gap-----·- ---------- -- ------ ------·--
Stagger -- ------ --- ---- -- -- -·-----
Span of lower wing .. .. ... .
Chord of upper wing . ... . .
Chord of lower wing ..... .
Supporting surface
(incl. axle fairing) ..
Useful load .. ...
Gross weight _
Wi.ng loading ---­Power
loading ...
Power plant ...
22 ft.
19 ft. 8-1 /2 in.
8 ft. 1 in.
Cut·tiss C-80
38 in.
11-1 / 4 in.
20 ft.
56 in .
10 in.
149.02 S Q. ft.
389 lb .
21i;o lb.
14.9 lb./sq_ ft.
3.73 lb. / h . p.
Curtis s V-1400
lo----------J9~8.z'k -·---------<
~--
GENERAL ARRANGEMENT OF ARMY-CURTISS RACER R3C-1 WITH V-1400 ENGINE.
(From preliminary drawing)
AIRCRAFT DEVELOPMENT
One of the most important and interesting features of the design is the power plant, the Curtiss
V-1400, an entirely new engine recently devolped by the Curtiss Company for pursuit purposes,
under supervision of the Army Air Service. The V-1400 (see description on page 40, T echniwl
Bulletin No. 42) is a 12-cylinder, water-cooled vee type engine weighing about 710 pounds com­plete
with accessories. It has a normal rating of 500 hor sepower at 2100 revolutions per minute.
but when fitterl with high rnmpression pistons the output is around 590 horsepower. The entire
in stallation including tanks, radiator s, piping an cl propeller weighs about 1100 pounds.
As in stalled in the racer the engine cannot be started by the pilot without assistance since the
starting system is external ancl entirely separate from the airplane. The system incorporates a
han?-operated ~ta rtin g magneto with wiri;1g that can he plugged into the ignition system l'll the
engme.
Only the most necessary equipment is carried. T11is includes a few navigating and engine
controls in struments. As a landplane the useful load aggregates 389 pounds disposed as follows:
pilot-ISO pounds, twenty-seven gallons of foel-175 .5 pounds, four gallons of oil-32 pounds,
and safety belt-LS pounds. The fuel is sufficient for 48 minutes flight at full throttle at an esti­mated
speed between 255 and 260 miies pe;· ho ur.
As a seaplane, the racer is equipped with twin pontoons in place of the land undercarriage, and
its designation changed to Model R3C-2. The fuel capacity in this case is increased to 60 g-allons,
giving an endurance of 1.3 hours at full throttle. The performance a s a seaplane is estimated at
240 miles per hour.
Static tests have been conducted at the Curtiss factory under supervision of that organization
and an engineer from the Division acting in a con sultin,; capacity. The results di sclosed the struc­tural
strength of the R3C-1 racer to be satisfactory for flight except for a few in stances in which
minor parts of the structure required strengthening. In high incidence condition the wings with­stood
a load factor of 12.5, one-half factor over that required, and . in low incidence condition
which corresponds to inverted flight a factor of 4 was sustained as required. The fuselage showed
adequate strength by sustaining a load equivalent to one-half factor in excess of the required
twelve, whereas the chassis and tail skid withstood drops of 24 inches and 30 inches, respectively,
and were found satisfactory. All control surfaces including ailerons, elevator, fin, rudder and
stabilizer sustained loads of SO pounds per square foot which is well over the individual load re­quired
in each instance. The controls including st ick, rudder pedals and linkage functioned sati s­factorily
under loadings exceeding those actually required. \ \That failures did occur were mostly
of minor nature and easily corrected.
Brakes for Airplanes.
The application of brakes to all types of airplanes used by the Army Air Service. particularly
present ser vice types, is und e~· consideration . The project involves a design study of the type of
brake best adapted to the airplane landing wheel , rel ocation oE chassis wheels to preserve equili­brium
of the airplane during braking deceleration, and analyses of increased concomitant fu selage
stresses and tail skid loads. Studies on commercial brakes and disk wheels are also included.
In order to test the efficacy of this idea a DT-2 (Douglas) a irplane used at the Division for
drop-testing parachutes was equipped with brake s, one on each landing wheel. Each brake was
operated independently by a pedal, similar ro that used on an automobile for this purpose, mounted
above the rudder bar in the pilot's cockpit. The brake consists of two large metal di sks, one bolted
on the outside of the wheel and the other mounted on the outer encl of the ax le in such a 111an11er
that it bears against the wheel disk when the Lrake pedal is depressed. This outer disk is faced
with brake lining and riveted near the hub to a :ornaller disk against which the brake earns operate.
These cams are actuated by flex ible cables connected to the pedal thru the hollow axle strut.
By using two pedals, one for each brake, either wheel can be braked independently by depressing
the proper pedal.
Quite surpri sing results were obtained in a preliminary demonstration with these brakes. In
a normal landing the DT-2 airplane rolled approximately 980 feet before it could he brought to a
stop. By applying the brakes this di stance was shortened to about 340 feet. Another advantage of
nsing the brakes resulted in increased manuever ability in taxying. By braking each wheel inde­pendently
the pilot is enabled to produce turns to right or left as desired, a manetwer that is more or
less difficult to execute by the usual slipstream-rudder effect s alone. In view of the success at-
14 T E C H N I C A L B U L L E T I N N o. 43
tending this demonstration, designs are being prepared for the adaptation of brakes to pursuit
aircraft. As a rule this type of airplane requires a long rolling di stance after landing cine to its
inherent high landing speed. The use of brakes on pursuit as well as on larger aircraft will per­mit
their safe operation from small field s.
AIRSHIPS AND BALLOONS
RS-1 Airship.
Erection of the R S-1 airship at Scott Field , Illinois, which had been delayed on account of
accidental failure of a cable sleeve extending th ru the hallonet diaphragm as referred to in the
last number of Technical B ulletin, has been finally consumatecl in cooperation with representa­tives
of the Goodyear T ire & Rubber Company who were si.1pervising the pro ject. The design
of the cable sleeves has been changed to obviate possible recurrence of similar failures, and the
airship is now being inflated with helium recently received from F ort vVorth, T exas. Preparations
are being made for full scale deflection test s along the lines of the water model tests conducted
by P rofessor Hovgaard of the Massachusetts In sti tute of T echnology as well as fo r a number of
strain gage measurements during the flight tests.
At the time the RS-1 airship was designed, there were no suitable engines of 300 horsepower
or 600 horsepower avail able. Consequently, it be came necessary to adopt the Liberty engine for
the power plant. This was composed of four Lib erty engines, two in each power car driving one
large propeller thru a dual tran smi ssion. Each engine was choked to give only 300 horsepower for
dirigible use, making a total output of 1200 hor sepower. Naturally this in stallation was bulky and
heavy in proportion to the power output, and so, in 1924, when two new engines, the \!\fright T -3
of 600 horsepower and the Packard l A-2500 of 800 horsepower, became available, a study was
made to determine the possibility of substituting either of these engines for the Liberty. This study
finally resulted in the production of a complete d esign incorpora ting one P ackard engine, choked
to 600 horsepower, to replace the dual Liberty in stallation in each power car, thereby effecting
an estimated saving in weight of 2500 pounds. A not her design of still greater effici ency from tlie
weight-saving standpoint is now under considera tion whereby it is proposed to use onl y a single
power car with two Packard l A-2500 engines in stead of the two power cars with dual Liberty
in stallations as at present. However, both of these proposed designs using the Packard engine are
being held in abeyance pending flight tests of the airship with .the original power plan t.
\Vith regard to the in stallation of wate r rec overy apparatu s on the RS-1 air ship, prn \'ision
for which was made in the design. the E ngineering Division has closely observed the iunctioning
of similar apparatus on the air ships, " Shenandoah" and "Los Angeles ." in order that the experi­ence
of the NaYy air service might be utilized to the full est extent. Meanwhile. t!1e necessa ry
engineering data have been prepared which will enable the in stallation of water recove1·y apparat11s
on the J{S-1 to be made at slight expense as s0011 as funds become available for thi •; purpose.
200-Foot Mooring Mast for Scott Field.
In order to accommodate the new RS-l air ship as well as any other large air ships. the Ani1y
Air Service has placed a contract with the l\ircr a ft Development Corporation , Detroit, Michigan ,
for the construction and erectirm l•f a 8teel mooring mast at Scott F ield, Belleville, Illinois. T he
mast is to be not less than 200 feet high as measu reel from th e ground level to the mooring point.
No furth er in formation can be given at this writing since the details of the design have not yet
been decided upon.
New Gas Cylinder Cleaning and Painting Machine.
A new gas cylinder cleaning and painting ma chine. patterned 1a fter an eadier experiment:il
machine of this type, has been deii ve rer] to the E ngineering Di vision by the Macl eod Company, Cin ­cinnati
, Ohio. T he new machine is designed to thorol y clean and paint standard gas cylinders
(used for storing hydrogen and helium) at tw o rates of speed , either 30 or 60 per lwur, de­pending
upon the co ndition of the cylinder s. The cleaning is effected by mean s of sand blasting
and wire brushing, and the paint ing by a spray ing process operated by com p res~ed air, the en­tire
procedure being continuous.
A I R C R A F T D E V E L 0 l' ~T E N T 15
The machine is portable. It is built in two units mounted upon rubber tired wheels which enable
them to be easily trailed to any desired operating position. One unit comprises thr. cleaning and
painting outfit and the other the power unit. The latter consist s of an air compressor driven by
a gasoline engine which also operates the conveyor and exhaust fan. The compressed air is used
for the sand blast and paint spray. \!\/hen the machine is in operation the cylinders are placed on
the advancer rack which carries them thru the cleaning apparatu s. From there the cylinders are
past thru a vacuum cleaner equipped with a special fi ber brush which removes all traces of dirt or
dust adhering to them before they enter the paint cabin et. In passing thru this cabinet which contains
ing a battery of oscillating paint-sp raying nozzles, the cyli nders are not revolved but are advanced
on four pins to prevent the paint rubbing off. The drain from the paint cabiPet is removable to
facilitate cleaning af ter each operation. T he entire machine is constructed in detachable section -;
to facilitate shipment.
P rior to delivery, demonstrations were made at the contractor's plant in the presence of En­gineering
Division representatives in which several cylinders were cleaned and painted in one con­tinuous
operation at different rates of speed depending upon the condition. At the Division the
tests will involve the cleaning and painting of over 1500 standard gas cylinders.
ARMAMENT
External Bomb Hoist, Type E-1.
A new bomb hoist designated as the T ype E-1 has been evolved and standardized fo r use on
all external bomb racks developed by the Army A ir Service. The new hoi st weighs onl y 24 pounds
completely assembled ; yet it is capable of handling all sizes of aircraft bombs ranging in weight
from 100 to 2,000 pounds inclusive with ample safety. For heayier loads such as 2,000-lh. and
4,000-lb. bombs, the hoisting units from two Type E-1 hoists are used directl y on the bomb rack
itself without the beam.
HOISTING A 2,000-LB. BOMB WITH TYPE E-1 BOMB HOIST UNITS.
16 T E C H N I C A L B U L L E T I N N o. 43
T he Type E-1 external bomb hoist consists essentially of a formed sheet steel beam position­ing
two removable cable drums, one at each encl. Each drum incorporates a ratchet mechanism for
winding the hoi sting cabl e, extra leverage being obtained by means of an extension lever slipped
oyer the ratchet handle. The opposite encl of this lever is shaped like a crowbar in order that it may
also be used for moving the heavier bombs into position for rai sing . By using two different sizes
of drums, large ones for bomb loads up to 2,000 pounds and small ones for 2,000-lb. and 4.000-lb.
bombs, together with the proper size hoisting cables and slings, the entire range of standard bombs
can be accommodated.
In use the hoist is simply laid across the tee rail of an ex tern al bomb rack midway between its
supports. \Vhen the beam is placed in the proper position, the hoi sting drums project suffic ientl y on
each _ide to clear the rack and permit the bomb to be easily raised and attached to it. The hoi st is
used for rai sing 100-lb .. 300-lb., 600-lb., and l ,100-lb. bombs (or combinations of same up to
2.000 pounds) to their r espective racks, types B-2. B-3. C-2. and C-3, when equipped with two
large size cable drums, each carrying seven feet of 3/ 16-inch flexible steel wire cable, and an idler
pulley positioned in the proper location on the beam. For rai sing 2.000-lb. and 4.000-lb. bombs to
the Type H -4 external bomb rack, the beam of the hoist is dispensed with. and four small hoi sting
drum units are remowcl from. two Type E-1 hoi sts and inserted directly in the steadying yokes of
the bomb rack itself in suitable receptacles provided therein . Each of the small drums is wound
with four feet of extra strong cable, 7 / 32 of an inch in diameter. The winding of the hoisting
drums in all cases is made easy through the magnified leverage provided by the extension lever
over the handle of the ratchet mechani sm.
EXTERNAL BOMB HOIST, TYPE E-1.
A IR CRAFT DEVELOP MEN T 17
\ \Tith the Type E-1 hoist it is possible for two inexperienced men to load any size bomb on its
respecti ve rack with comparative ease. \i\Tith a little practice even the large 2,000-lb. and 4,000-lb.
bombs which require the use of four hoi sting uni ts, two at each end of the bomb rack, can be easily
rai sed and attached to the rack within five minutes.
Ten hoists of this type are under construction for service test.
New Type B-5 Bomb Shackle to Replace Type B-4.
An improved bomb shackle, designated as Type B-S, has been designed to supersede the
present standard T ype B-4 bomb shackle which has been in service for the past two years for
TYPE B-5 BOMB SHACKLE.
carrying 100-lb .. 300 lb., and 600-lb. bombs on internal racks and 1100-lb. bombs on external
racks. Types C-2 and C-3. The new shackle has a very high factor of safety when carrying the
1100-lb. bomb and requires much less force on the trigger to release the bomb than the Type B-4
shackle with the same load.
In general construction, the T ype B-S bomb shackle shown above is a redesign of the Type
B-4 shackle having the some overall dimensions but with certain portions of the frame, the latch ,
and the connecting link made stronger. The new shackle is made more resistant to corrosion
through the use of Parkerizing and stainless steel. By Parkerizing, the entire surface of the shackle
is uni formly finished and protected whereas with zinc plating by the electrolytic process, as former­ly
used, only certain portions of the surface were heavily coated while others received practically no
protection.
The Type D-S shackle will replace the Type B-4 shackle as soon as sufficient quantities become
available. Until then, the latter will be used for carrying all bombs up to and including 600 pounds
in weight.
18 T E C H N I C A L B U L L E T I N N o. 43
Rack for 4,000-lh. Bomb Ready for Service Test.
Ten H -4 bomb racks of the type shown on page 15 in connection with the in stallation of E -1
bomb hoist units are being built for service test. This rack, an external type, is designed for
use on the Martin l\fB-2, the Curtiss NBS-1 , and the new Huff-Daland XLB-1 bombers for carry­either
the 2,000-lb. or the 4,000-lb. bomb. In addition to carrying the bomb this rack also provides
means for rai sing it hy furnishing a support for the Type E -1 hoisting drums which in this case
are used without the hoisting beam as explained in the foregoing article "External Bomb Hoist. Type
E-1." By means of these hoists when installed in the steadying yokes of the rack, the bomb can
he raised in place by an unskilled crew in less than five minutes.
On the Type H -4 rack the mechanism that carries and releases the bomb is contained in and
supported by the tee rail of the rack. This mechanism is of simple construction, having a high
factor of safety as based on the 4,000-lb. bomb load. T he releasing device which operates the rack
is so designed that the movement of a single !ever of the release handle (the Type L-12 which is
specially designed for this rack) in one direction from a locked neutral position releases the bomb
"armed" whereas a similar movement in the opposite direction releases the bomb "safe." In either
ca"e the force required to release the bomb is not more than ten pounds.
Due to the use of light, high-strength materials, the Type H -4 external bomb rack has a
weight of only 112 pounds completely installed. It is attached to and supported on the airplane by
means of the steadying yokes placed at each end of the tee tail. Besides providing an anchorage
for the bomb hoists as previously mentioned, these yokes also serve to steady the bomb and keep
it from swaying by means of adjustable studs bearing against it. The rack has functioned satis­factorily
in recent ground and flight tests with the 2,000-lb. bomb (actual weight 2,100 pounds)
installed on the NBS-1 airplane.
Pyralin Beads for Gun Sights.
Pyralin is heing tried as a material for the head on post gun sights to replace the vegetable ivory
in present use. The new material appears to have several ad vantages in that it will not break,
gives better visibility ancl is more desirable for production purposes. A sufficient number of beads
has heen made from pyralin rods furni shed by the Du Pont Company to equip ten sights for service
tests.
EQUIPMENT
Visual Indicator for Radio Beacon Signals.
A visual indicator whereby signals emanating from a radio beacon are made visible to the
pilot has been clneloped and tested with considerable success in preliminary flights directed from
the radio beacon station at \ i\Tilbur \ i\T right Field, Fairfield, Ohio. This instrument when con­nected
with the regular airplane radio receiving set flashes a series of signal lamps mounted on
the pilot's instrument board to indicate the deviations of the airplane from the course as directed
hy the beacon, a white light indicating that the correct course is being flown and a reel or green
light the respective deviation to left or right therefrom. With the present apparatus which weighs
twenty-four pounds, signals have been successfully indicated as far as fifty miles from the beacon.
The possibility of greatly increasing this range is not immediately apparent, but the weight of the
apparatus can be substantially reduced. Visual indication for raclio-clirectecl flight affords a great
advantage over audible indication in that it is unnecessary for the pilot to wear a radio helmet.
In connection with the extension of the radio beacon system the Engineering Division has
prepared the necessary equipment for the establishment of a radio beacon station at Monmouth, Ill­nois.
for use of the air mail service.
Incandescent Beacons and Landing Lights.
l{ecent advance in the design of night-flying equipment has centered upon the development and
standardization of the high power incandescent electric lamp as a substitute for the carbon arc in
aerial beacons and airclrome floodlights and as a means of increasing the 'illuminating efficiency of
airplane landing lights. In accomplishing this work the Engineering Division has received excel­lent
cooperation from the various lamp manufacturers.
j
AIRCRAFT DEVELOPMENT 19
One of the most important steps in this development is the standardization of the 24-inch 111-
candescent revolving beacon used by the night air mail and night airways service. This beacon is
equipped with a lamp-changing mechanism which automatically replaces the burned-out lamp with
a spare one and at the same time automatically signals this change to the operator who can replace
the burned-out bulb without delay. Another step in development is the production of a satis­facto
ry IO-kilowatt, 110-volt incandescent lamp for use in large aerial beacons and floodlights. A
lamp of this type is being used in converting several 36-inch high intensity arc searchlights into long
range incandescent revolving beacons as shown on page 20, Tcch11ical Bul!cti11 No. 41.
For floodlighting, the Pyle-1 'a.tional 23-inch incandescent searchlight has been placed under ob­servation
and found suitable for this purpose when equipped with a 12-volt, 100-ampere incandes­cent
lamp and a beam diverging lens.
Improvement of the standard airplane landing light has also been attempted by having vari­ous
manufacturers submit sample lamps for comparison with the air service standard 12-volt,
3S-ampere lamp now used in these lights. In the photometric tests a special 12-volt. SO-ampere.
SO-hour-life Edison lamp similar to that used by the air mail service showed a slight gain in il­luminating
efficiency at the expense of reliability. Similar tests on a 'vVestinghouse lamp of like
specification disclosed a small increase in beam divergence but a loss in maximum beam candle power
in comparison with the lamp used by the air service.
The question of ii1creasing the beam candlepower of the standard airplane landing light above
300,000, its present intensity; has also received attention. To determine the advisability of in­creasing
the beam candlepower of these lights, a Pyle-National 23-inch beacon was fitted with a
short focal length metal reflector and mounted in a Martin Bomber for trial as a landing light.
The intensity of the beacon which has a beam candlepower of 2,SS0,000 proved too great for this
purpose and indicated that there was no advantage in greatly increasing the candlepower of the
cent lamp and a beam diverging lens.
Night Aerial Photography by Flashlight.
Various methods for taking aerial photographs at night hy flashlight are under investigation.
In preliminary ground tests (see page 32, Techni ml Bulletin No. 42), it has been found that satis­factory
photographs can be obtained over a distance of 2SOO feet with a SO-lb. charge of specially
prepared flash powder at a flash speed of 1/2S of a second. The next step in this investigation in­volves
the finding of a suitable means for exploding the flash powder in the air. A tentative safe
method by which this may be accomplished is described in the following paragraph.
By experiment it was found that the flash powder could be placed in a small torpedo and towed
at a safe distance behind the airplane. A test with a dummy torpedo showed that any increase or
decrease in the speed of the airplane regulated the distance above or below the airplane at which
the torpedo would glide thru the air. For instance at an airspeed of 70 miles per hour, the tor­pedo
would assume a position about SO feet below and 150 feet to the rear of the airplane, whereas
at an airspeed of 100 miles per hour it would glide steadily about lSO feet to the rear and about
10 feet above the airplane.
Some consideration is being given the use of gliders for this work. This method contem­plates
the use of a small glider similar to a target glider which could be loaded with fla sh powder
ignited by a delayed fuse, and released from a photographic airplane when at the proper altitude.
"Quick-work" Photography.
A new "Quick-work" process in aerial photography was successfully demonstrated at the Mili­tary
Tournament held at Chicago recently. In this preliminary demonstration aerial photographs
were taken, developed, printed and dropped completely fini shed within ten minutes after exposure
from an airplane in flight. The feat was accomplished without landing by means of special auto­matic
photographic apparatus, films and developers installed in a DH-4B airplane which had been
remodeled for this purpose. The average time required to deliver a finished photograph was <tbout
ten minutes after exposure provided the point of delivery was within a short flying di starcc of the
point of exposure. Similar demonstrations were made later at Rochester. N. Y .. in cooperation
with the Eastman Kodak Company for the purpose of perfecting the process.
New Mount for T-1 and T-2 Cameras.
A new mount known as T ype A-4 has been developed for use with the Army Air Servicp T-1
(three lens) and T-2 (four lens) mapping cameras. The mount is of all metal construction,
20 T E C H N I C A L B U L L E T I N N o. 43
weighing fifteen and one-half pounds. A special feature of the mount permits it to be rotated thru
360 degrees- a complete revolution-and locked in any position. Another feature permits the
camera to be tilted for leveling at least five degrees in any direction. The new mount provides
more leg room in the cockpit for the operator than former types.
New View Finder, Type A-2.
A new vertical view find er, Type A-2, is ready fo r production. The new model incorporates
several important improvements over the present standard Type A-1 , chief among which is the
addition of four folding lids which, when r:ot in use, fold one upon the other to form a door
over the top of the finder to protect the ground glass and level from dirt and damage. In making
observations these lids al so serve to shield the ground glass from the light, thereby giving the pho­tographer
a n~uch clearer image of the ground Lelow. The new in strument is designed to take a
Bausch & Lonib Tessar No. 17 lens having a focal length of one and three-eights inches in order to
utilize the supply of several hundred lenses of th is size now in air service stores inasmuch as these
lenses are unsuitable for any other purpose. Several Type A-2 view finders have been recom­mended
for service test.
Photographic Equipment on DH4M-2P Airplanes.
Inspection of the mock-up showing the prop osed in stallation of photographic equipment in
twenty-five photographic airplanes, Model DH4M-2P, under production contract with the Atlantic
Aircraft Corporation, H asbrouck H eights, New Jersey, indicates that these machines will be the
best photographic airplanes so far produced for the Army Air Service. This airplane will accom­modate
all standard and tentative standard types of air service aerial cameras, including the new
four-lens camera, Type T-2, recently designed by the E ngineering Division for aerial mapping.
POWER PLANTS
High Speed Engine Development.
A successful attempt has been made to secure more po\ver from a Curtiss D-12 engine by
increasing the operating speed without increasing the weight. F or this purpose an engine was
obtained, modified for high speed operation and subj ected to a standard fifty-hour endurance test
which is still in progress. After 17 hours running at 2800 r. p. m. , the engine was disassembled
and found in a satisfactory condition. It was th en reassembled and fitted with a. rotary inducting
system for dynamometer check tests. Results obtained with this system showed an output of 552
horsepower or an increase of 105 horsepower over that normally obtained with this engine. T he
tests were unfortunately terminated by bearing tr ouble but will be resumed as soon as new bearings
are received and the engine is again · placed in running condition.
The increase in hor sepower of thi s engine at this speed is directl y attrihutecl to the use of the
rotary induction system. A study of this system as applied to vee type engines is in progress.
Three Air-Cooled Liberty Engines on Order.
Three air-cooled Liberty engines have been o rdered from the Allison E ngineering Company.
Indianapolis, Indiana. These engines will be similar to the first experimental model designed and
assembled by the E ngineering Division from parts supplied hy this firm-see page 29, T echnical
Bulletin No. 41. One engine will be of the direct drive type, whereas the remaining two will be
equipped with an Allison type epicyclic reduction gear incorporating a spring coupling and H off­man
roller planet hearing. Other modifi cations in clude a simplified rotary induction system and a
lubricati11g system designed for inverted operation.
The air-cooled Liberty is a modification of the standard Liberty engine 1ncorporating air­cooled
cylinders, new pistons, special overhead camshaf t s and a rotary induction system. Cooling
is effected by means of cowling which directs the propeller slip stream into the vee from which the
air is fo rced to escape between the cylinders. The engine has a bore of 4-5/ 8 inches and a stroke
of 7 inches which gives a total piston displacement of 1411 cubic inches. It has a rated output of
400 h. p . at 1800 r. p. m.
The experimental model has successfully completed a standard SO-hour endurance test at the
Division.
A IRCR AF T DEVELOPMENT 21
To Build 1200-h. p. Air-Cooled "X" Type Engine.
Success in air-cooling high powered cylinders in the vee arrangement · as demonstrated in the
Engineering Division 's experiments with the air-cooled Liberty engine has led to the proposed de­velopment
of a large experimental air-cooled "X" type engine of 1200 horsepower to be desig­nated
Model X-4520. This engine will be built by the Allison Engineering Company, Indian­apolis,
Indiana, under an experimental contract recently awarded.
The proposed engine will have twenty-four cylinders arranged in four banks of six each,
forming an "X," with 90 degrees between banks to give equal firing intervals and uniform air
cooling. The bore and stroke will be 5~/,( inches and 7% inches, respectively, thereby giving a
total piston di splacement of 4520 cubic inches. The design incorporates a cylinder practically
identical to the Type "M" cylinder developed by the Engineering Division, a light ribbed type
piston similar to that used in the Wright R-1 and Curtiss R-1454 radial engines, and connecting
rods like those used in the Rolls-Royce "Condor" engine which transmit about the same power
per cylinder. The crankshaft is designed with hollow crankpin and main journals of large di­ameter
combining light construction with maximum torsional rigidity. These journals measure 1
inch in width by 4}4 inches in diameter at the main bearings and 4-5/16 inches in width by 3.~
inches in diameter at the crankpin. Plain bearings will be used in the rods and roller bearings on
the crankshaft as in the Napier "Lion" and "Cub" engines, the latter bearings finding rigid sup­port
on the thick webs of a tunnel type crankcase. Since this crankcase has no parting along its
longitudinal axis it is necessary to assemble the roller bearings on the crankshaft prior to its as­sembly
in the case.
A 10,000-foot gear driven centrifugal supercharger of the suction type is being incorporated in
the design as an integral part of the engine.
One of the features of the installation is the method of mounting the engine in the airplane.
This is effected by means of four tripods arranged concentrically about the engine in such a
manner that one leg of each tripod supports the front end of the crankcase and the other two the
rear with their apex making the attachment with the fuselage. The weight of the power plant
completely installed. that is, including engine, propeller hub, reduction gear, all accessories and sup­ports
iis estimated at 2400 pounds or approximately two pounds per horsepower.
By the terms of the contract the Allison firm will manufacture one experimental engine for
delivery about January, 1926. Complete details of the cylinder design , the patterns for the cylin­der
head and the cylinder castings will be furnished by the Engineering Divi sion.
RESEARCH AND EXPERIMENT
I
RESUME OF ENGINEERING DIYISION
SERIAL REPORTS.
Serial R eports marked with an asterisk (*) will
be 'issued by the Chief of Air Service as
"Air S ervicc Inf ornwtion Circulars."
AIRPLANE SECTION.
Analyzing and Predicting Airplane Performance. *Serial No. 2355
The formulas given in this report are presented to show what relation certain fundamental
variables used in predicting airplane performance bear to absolute ceiling and rate of climb in order
that these quantities may be estimated with a minimum amount of calculation. The conventional
methods of calculating performance with the exception of the empirical-theoretical curves are quite
laborious in that the curves for horsepower avai lable and horsepower required have to be com­pletely
calculated and drawn for at least two altitudes. This is unnecessary inasmuch as only three
points in each of the above curves are required, namely; horsepower required and avai lable at high
speed, maximum ceiling, and best rate of climb. 1' hese power curves may be expressed algebrai­cally
to a very close approximation from which it is possible to calculate the co-ordinates of each of
the above points. As soon as these co-ordinates are known the procedure of determining high
speed, rate of climb, and cei ling fo llows standard practice. It is shown that the results obtained by
the formulas advanced in the report are probably as accurate as those obtained by flight test with
which they are compared. T he formulas are prese nted for general use.
Stress Analysis of' Phillips' "Alouette" Airplane. *Serial No. 2470
T his report contains the stress analyses of the wing, fu selage, and landing gear structures of
the "Alouette" airplane. No analysis of the tail surface is included, sin.ce it was impossible to ob­tain
the size of members in the structure without disassembling the surface. The tail group was
therefore subj ected to static test, the results of which are appended, and found satisfactory for
flight.
The "Alouette" is a light airplane of the sin gle bay biplane type, built about ; 60-h.p. Law­rance
L-4 air-cooled radial engine. I t has a span of 18 feet, supporting surface of 94 square
feet including aileron s on upper wing, and a total weight of 846 pounds. The useful load totals
299.5 pounds disposed as follows: pilot- 180 pounds, 11 .5 gallons of fuel-65 pounds, 2 gallons of
oil- 16 pounds, and equipment-20.5 pounds. On performance test it showed a high speed in level
flight of 94.8 m. p. h., and an endurance of 3.Yz hours at 10,200 feet, the service ceiling. Landing
speed approximates fifty miles per hour.
P hotographs of the airplane are appended.
Torsional Test of Elias XNBS-3 Fuselage. *Serial No. 2481
This is a report on the torsional test of the fuselage of the E lias XNBS-3 night bombardment
airplane. Similar tests were conducted on the NBS-1 (Martin bomber) and XNBS-4 (Curtiss
night bomber) as stated on page 43, T echnical Bullcti11 No. 42, in comparison with which the NBS-3
fuselage yielded the least in torsion under an eccentric (one-sided) horizontal tail load of 7 Yz
pounds per square foot. This fuselage which is of rivetted duralumin tube construction is there­fore
considered the most rigid of the three in regard to torsional rigidity.
RE S E AR C H A N D EX P E ;~ I '.\[ E N T 23
Design of Plywood Webs for Box Beams. *Serial No. 2500
This study was initiated for the purpose of developing a practical method for the design of
efficient wooden box beams having spruce flanges and plywood webs. Before much had been clone,
however, the Forest Products Laboratory issued a report "The Influence of the Form of a Wooden
Beam on its Stiffness and Strength" recommending a method for the design of the flanges which
was adopted by the Engineering Division, thus curtailing the scope of this investigation. How­ever,
the study of other factors in the design of wooden box beams was continued, and a number
of static tests made, the results of which were compared with the data obtained by the Forest Pro­ducts
Laboratory. These data show the values to be used in the design of plywood webs. the use
of web stiffeners, the glue area, and other pertinent factor s entering into the design of this type
of beam.
Study of Wing Weights. *Serial No. 2527
The value of knowing the approximate weight of various airplane parts before the airplane is
completely designed and detailed has been recognized for some time. and as a result numerous in­vestigations
have been made from time to time in an attempt to find some constant weight ratios
common to all airplanes by which this could be predicted. For instance, the weight of the wing
which is dependent upon many factors such as gross weight, designed load, type of construction,
wing area, aspect ratio, airfoil section, type of landing gear, and location of power plant and fuel
tanks, varies between 10 and 20 per cent of the gross weight of the airplane. To predetermine
what percentage is necessary to obtairi the best results for a given type of airplane would save
much time and expense. In trying to find some definite relations by which this could be accom­plished
this investigation was carried along two general lines as discussed under Parts I and II of
the report, without success. It is predicted, however, that the time will come when it will be pos­sible
to determine some definite relationship between the total weight of the wing and that of its
constituent parts as well as the total weight of the airplane.
Several tables and charts are appended.
Effect of Sweep Back and Sweep Forward on an Airfoil. *Serial No. 2558
In this investigation it was found that the sweeping backward or forward of the tip section
of the UAS-35 airfoil with respect to the root section did not apparently affect the li ft or drag to
any great extent within the limits of this test. It was also shown that stability computations may
be based on the mean chord of the altered airfoil and the center of pressure characteristics of the
normal airfoil, with probably small error. Although extreme cases in this test indicate that the
center of pressure is shifted somewhat in the direction opposite the sweep, this general rule is not
borne out in the intermediate cases.
Airplane Design.
The following reports will be published by the Engineering Division as ati Air Service hand­book
entitled Airplane Design. This book which is in the process of publication is a revision of the
handbook, "Structural Analysis and Design of Airplanes," which appeared in 1920.
Serial No. 2497-Chapter V, "Prediction of Performance."
Serial No. 2496--Appendix to Part V.
Serial No. 2472-Chapter VI, "Loads on an Airplane."
Serial No. 2473-Appendix to Part VI.
Static Tests Conducted at the Engineering Division.
Complete accounts of static tests recently conducted by the Army Air Service Engineering
Division at McCook Field to determine structural fitness of airplane and airplane parts for flight
will be found in the following reports. Each report contains a description of the structure, the
method of test, and a discussion of the results.
*Serial No. 2471-Experimental Steel Spar designed by the Engineering Division.
*Serial No. 2491-Thomas-Morse Duralumin Test Spar.
Serial No. 2494-Proof Test of Special Stabilizer and E levator for Boeing Pursuit PvV-9.
Serial No. 2495-Proof Test of Standard Stabi lizer and E levator for Boeing PW-9.
Serial No. 2501-Aeromarine Experimental Duralumin Spar (Second article).
*Serial No. 2523- Curtiss Observation Airplane Model X0-1.
Serial No. 2526--Special DH-4B Upper Wing Center Section carrying fuel tank.
24 T E C H N I C A L B U L L E T I N N o. 43
Wind Tunnel Tests.
In the following reports will be found aerod ynamical data on various airplane models and sur­faces
as determined in the wind tunnel.
*Serial No. 2469-Model of Heavy Night Bomber with centralized power plant.
*Serial No. 2485- Appendix to Air Service Information Circular No. 478 "Wind Tun­nel
Tests of 36" x 6" Air foi ls," including C-62 and 62A, USA-4SM,
Eiffel 385, and Clark "Y" Nos. 15, 18, and 21.
Serial No. 2505-36" x 6" Airfoils at Various Speeds (Includes airfoils USA 16 and
3SA, RAF 15, Gottingen 387 and 429, Clark "Y," and NACA 77).
*Serial No. 2506--Transport Study About Geared Engine.
Serial No. 2515-Aileron C!mracteri stics as Affected by Design and Air foi l Thickness.
This report also contains an appendix on "Yawing Moments Due to
Ailerons."
Serial No. 2538- Tests and Results Required on Complete l\foclels in \Vind Tunnels.
Serial No. 2546--Moclel of Proposed Single Engined Heavy Bomber, Type LV-XIII-2.
Serial No. 2556--Model of Proposed Monoplane Racer with two Packard 1,500 en-gines
in tandem.
EQUIPMENT SECTION
Test of Oxygen Regulator, Prouty Type. Serial No. 2498
T his report contains the results of a test to determine whether or not a sample oxygen appara­tus
of the Prouty type submitted by the Gaertner Scienti fic Corporation of Chicago, which is manu­facturing
500 of these instruments, conformed to the Air Service specification.
Test of Carter Gasoline Gage. Serial No. 2512
A Carter gasoline gage submitted by the Pyrene Manufacturing Company, Newark, N. J.,
was tested and found unsatisfactory for aircraft use. T his instrument is a distant indicating gage
operating on the hydrostatic principle. The pressure of the head of liquid in the tank is measureCt
by means of a sensitive pressure indicator on the clash. This indicator consists of a sensitive me­tall
ic diaphragm which in expanding actuates a co unterbalanced pointer through a system of levers.
This gage is built for the motor car trade which does not require such high grade construc­tion
and workmanship as required in aircraft instruments.
Method of Reducing Flight Test Data to Standard Air. Serial No. 2521
The methods and standards used in the reduction of flight test data to standard, for the pur­pose
of comparing airplane performances, have varied widely. The results, therefore, are differ­ent.
This means that performances of airplanes tested at one station cannot be compared with
those obtained at other stations due to the vibrations in atmospheric conditions and methods of ap­plying
the corrections. T he report described in detail a standard atmosphere and a method of
reducing the observed data to standard. The necessary procedure, charts and tables by which this
may be accomplished are given in the report.
FLYING SECTION.
Performance Tests.
The following serial reports contain detailed accounts of the performance tests conducted by
the Army Air Service Engineering Division at McCook F ield.
Serial No. 2488-Fokker Pursuit PW-7 with Curtiss D-12 Low Compression E ngine.
*Serial No. 2489- Curtiss Observation X0-1 with Liberty Engine.
*Serial No. 2502-Eng. Div. Observation XC0-6 with Inverted Liberty.
*Serial No. 2503-Atlantic Observation XC0-8 (Loening Wings and Liberty E ngine) .
Serial No. 2510-Consolidated Training PT-1 ( Hispano Model "I" 1 SO h. p. Engine).
Serial N'o. 2511-Consoiidated Training PT-1 (Hispano Model "E" 180 h. p. Engine).
RESEARCH A~D EXPERII\,fENT 25
Serial "To. 2513-Eng. Div. Observation C0-5 with Liberty Engine.
Serial No. 2514-Wright Observation X0-3 (Wright T-3 Engine and Wing Radiators).
Serial No. 2516-Douglas Observation X0-2 (Packard l A-1500 Engine and Small
Wings).
Serial No. 2520--Wright Observation X0-3 (Wright i-3 Engine, Two-bladed Dural
Propeller and Lamblin Strut Radiators).
*Serial No, 2524-Curtiss Observation X0-1 with Packard l A-1500 Engine.
Serial No. 2534-Cox-Klemin (Heinke!) Observation CK-C02 with Liberty Engine.
Serial No. 2537-Atlantic DH4M-2 with Liberty Engine and R. A. F. 15 Wings.
Serial No, 2541-Atlantic DH4M-2 with Loening \\Tings, R. A. F. 15 Wings, Liberty
engine and Wooden Propeller.
Serial No. 2542-Cox-Klemin (Heinke!) CK-C0-1 with Napier "Lion" Engine.
MATERIAL SECTION
Spoke Lacing on Airplane Wheels. *Serial No. 2518
The contemplated application of brakes and braking mechani sms to airplane wheels has
necessitated a study of the different t~pes of spo ke lacing with a view to adopting a type of lacing
most satisfactory for brake service. Five different types of lacing in various combinations were
investigated; those having radial spokes, tangential spokes or a combination of both; those having
the hubs centered or off center as a bracing for side thrust; and those having spokes on the bead
seat of the rim only or spokes in both the head seat and the drop center of the rim. Otherwise
the wheels were identical with respect to size, section and gage of rim, length of hub and flanges,
and number and gage of spokes. The wheels were tested for their performance under static load
and for their resistance under brake load as a measure of the relative rigidity of the different
types of spoke lacing. They were also tested under impact load and a combination of side thrust
and impact to determine their resistance to shock. As a result of these tests it was found that the
tangential type of spoke lacing is necessary to obtain a suitable and satisfactory wheel performance
when brakes are used, but that the radial type of spoke lacing as used in the standard Air Service
wheel is superior from both service and manufacturing standpoints.
Clogging of Fuel Strainers. *Serial No. 2567
·several minor investigations into the cause of the clogging of fuel strainers in airplane fuel
systems have been made at various times upon receipt of specimen screens filled with obstructing
deposits with the result that a sufficient variety of cases have been presented to enable definite
conclusions to be drawn regarding the source and remedy of this difficulty which in many in stances
has proved serious.
l, The accumulation of a jellylike precipitate of hyd rated aluminum oxide which practically
filled the meshes of the screen to the point where fur ther passage of fu el was impossible,
the precipitate being formed by the corrosion of aluminum parts of the fuel systeni by
water.
2. The accumulation of fibrous material, either asbestos or cotton fibers, which forms on the
screen a dense mat that holds back the fine suspended matter such as dirt or the corrosion
products of metals which would ordinarily have passed thru.
In the first case clogging caused by corrosion of aluminum by water has been overcome by
treating all aluminum parts as prescribed under Air Service Specification No. 98-20004-A, a
treatment that has proved effective in eliminating serious corrosion of aluminum. In the second
case clogging produced by fibrous materials has been prevented by inserting a screen of fine mesh
in the nozzle of the filling hose to which the source of this trouble had been traced.
POWER PLANT SECTION.
Instructions for Standard Engine Test and Report.
(Revised to March, 1925).
Serial No. 1506
This report gives an outline of the in format ion required in a standard engine test and the
form and order in which such information should be presented, in accordance with the latest ac­cepted
practice as revised to March, 1925.
26 T E C H N I C A L B U L L E T I N N o. 43
The purpose of the standard engine test is to obtain complete information concerning the de­sign
and performance of service engines for the use of aircraft and aircraft engine designers. It
is not applicable to engines in the experimental or developmental stage, or to incomplete or com­posite
engines. It consists of two distinct studies of the engine,-one the dimensional and weight
analysis of the engine and its parts and the other the clynamometer test for performance charac­teristics.
The information thus obtained is compiled in the form known as the "Standard Engine
Report."
Test of "Boyce-ite" Fuel. Serial No. 2467
It was found in tests with the single cylinder testing engine that "Boyce-ite" does not improve
the specification aviation engine fuels, and that none of the seven specific claims made for "Boyce­ite"
on the label of the container can be substantiated. These claims were refutted as fo llows:
1. That "knock'' is increased with normal spark advance.
2. That carbon continues to form, but is slightly less amounts than with gasoline or gasoline­benzol
mixtures without "Boyce-ite."
3. That "Boyce-ite" in any proportion decreases the power at least three per cent. (Tests
were made with the specified proportion of "Boyce-ite" 111 the fuel, with ten times this
amount and with 300 times this amount.)
4. That mileage would not be increased because the power is less when using "Boyce-ite"
than when using gasoline or gasoline-benzol mixtures, for the same rate of fuel supply
to the engine.
5. That in view of the above statements there is no substantiation for the remaining claims
advanced for "Boyce-ite" fuel.
From a chemical analysis, "Boyce-ite" appears to be a nitro-benzine, hydro-carbon mixture
manufactured by the Boyce & Veeder Company, Inc., Long Island City, N. Y.
Performance of Packard lA-1237 Engine with Modified Intake
Manifolds and Camshafts. Serial No. 2483
In comparing the performance of the Packard JA-1237 engine with the performance of similar
engines for pursuit service it was found that the output was somewhat lower than the average, and
in view of the smoothness of operation and low fuel consumption of the Packard engine it was
decided to investigate the possibility of increasing its power output and raising its normal speed
without making any major changes in the design. The cause of the low power was found to be
clue to the restricted induction system and inlet manifolding. By placing two duplex carburetors
in the vee with three cylinders supplied from each yenturi and at the same time changing the in­take
valve timing and Ii ft, a gain in power of 40 per cent resulted at 1400 r. p. m. and a gain of
2 per cent at 2000 r. p. rn., the gain in power in each case being attributed to the ramming effect of
the three cylinders supplied from one manifold and the change in timing. Pressure studies re­vealed
the fact that more than half the total drop in pressure was thru the inlet valve and port. This
restriction could not be appreciably reduced without redesigning the cylinders without which the
present output of the engine even with improved inlet manifolds would still fall below the average
for engines running at 2000 r. p. m. For these reasons any further development of the Packard
lA-1237 engine is not recommended without a redesign of the cylinders, the inlet manifolding and
the camshaft.
Performance of Stromberg NA-U6 Carburetor on Wright "H" Engine. Serial No. 2486
Performance data obtained in dynamometer runs conducted at the Division show that the
Stromberg production Model NA-U6 carburetor is very satisfactory for service on the Wright
"H" engine. The size of main metering jets recommended for ordinary flight service is No. 42.
For very warm climates or in extremely warm weather, however, size No. 43 jets should be used
provided their use does not decrease the power of the engine at full throttle, or produce unsatis­factory
acceleration.
This carburetor is designed and built by the Stromberg Motor Devices Company expressly
for use on the ·wright Model H Engine to replace the Stromberg NA-D6 (modified) and NA­D6A
carburetors for service use. It is superior in many ways to the standard NA-D6 type in
that it gives a much leaner mixture on propeller load without any sacrifice in smoothness thereby
R E S E A R C H A N D E X r· E R I ~.I E :-J T 27
effecting a material saving in fuel at cruising speed. It also makes idling more positive and freer
from tendency to load and gives good acceleration either in the air or on the ground. It has a mix­ture
control of easy adjustment giving ground lev el mixture ratios effective to approximately 18,000
feet, and the single venturi eliminates the possibilities of excessive fuel consumption caused by
frost or ice formation. Some data on the experimental NA-U6 ca rburetor obtained during the
tests are also given in this report.
Best Radiator Location for Maximum Speed. *Serial No. 2487
In order to find the best position for mounting the radiator to give maximum speed, fi ve types
of radiators of equal cooling ability were mounted in turn on a DH -4 airplane for comparative
tests as follows :
Kind of Radiator Equivalent Flat Plate Area
Curtiss wing skin . . . . . . .. . . . ....... . . . ... . .. .. . .. . .. ..... 13.23 sq. ft.
U nderslung (free air) . ... ... ...... . ..... .... . ..... . . . .. . 16.47 sq. ft.
Lamblin ....... . .................... . .... .. . .. . .. .. . ... 17.23 sq. ft.
C0-5 semi-free nose type above propeller ...... . ..... .. . . .... 16.58 sq. ft.
Oval, nose type . . . .. ... . . . . ... . .......... ... ... ... ..... . 16.69 sq. ft .
. The test s showed that the underslung radiator, mounted beneath the engine, gave results second
to those obtained with the Curtiss skin radiator, and that this type of racliator offers the best possi­bilities
as a service type giving maximum speed with required cooling and minimum maintenance.
Views of the various in stallations are appended.
Endurance Test of Liberty Engine Equipped with Various
Experimental Parts and Materials. *Serial No. 2490
This report covers an endurance test of a Liberty engine fitted with various special acces­sories
and experimental materials to determine th eir reliability and durability under full throttle
conditions. This test which covered a period of s everal months has been referred to from time to
time in T cclm-ical Bullct·in under the title "Liberty E ngine Parts Test," see re fe rences in T echnica.l
Bulletins Nos. 39 and 40, pages 36 and 26 respec tively.
Briefly the results show that sprayed babbitt bearings, Agr i!ite bearings, Kelmet bearings .
sprayed valves, sprayed pi stons, and camshaft housing vents failed in the test and therefore could
not be recommenclecl, but that Genelite and Durex bushings, stub-tooth gears, reinforced cylinders,
solid fuel connection s, Rockwell F ield water pump, Stryker cleaner, and jump-gap di stributor
passed the test successfull y and warranted furth er test.
Views of the various parts and accessories are appended.
INVESTIGATION OF MATERIALS
Investigation of British Doping Scheme.
Exposure tests in progress at the Division on the Briti sh doping scheme for aircraft fabric
covering indicate that this method of eloping reta ins tautness under conditions of high humidity to
a greater extent than the present eloping schemes in use by the Army Air Service. T he British
method consists in applying several coats of pigmented elope directly to the fabric without using
any intervening coats of clear dope. T he elope is made by pigmenting cellulose acetate dope with a
grayish white pigment, probably zinc oxide. A series of exposnre tests are in progress to deter­mine
the relative durability in comparison with the eloping scheme used by the Army Air Service.
Reliability of Welds.
The increasing use of welding in modern air craft construction has necessitated a study of the
various factors entering into the strength a11d rcli ability of the weld. This study embraces <in in­vestigation
of the effects of the various methods employed in welr! i,1.~, the types ,_:i f jr)ints made,
the chemical elements in tl 1e welding wire as well as in the material to he welded, a: 'd the dynamic
stresses induced by fatigue and impact.
28 T E C H N I C A L B U L L E T I N N o. 43
Fatigue tests on butt-welded steel tubes using either the direct current electric arc or tlie
oxy-acetylene flame with low carbon ,;tee! welding wire have shown that this tye of wcicl has an
effi ciency in strength equivalent to 50 per cent of the unwelclecl tube, when subj ected to alternating
tension and compression in a rotating be::-trn type testing machine. Welds made '"it'1 chn>me­molybdenum
steel welding wire. a stronger j(•int filling material, ,Showed a better microstructure
thru the weld. From present indications, it ap pears that the use of a stronger material in the
joint will afford greater resistance to alternating stre-;s1' S.
Protective Coatings for Steel.
T he relatiYe durability of various kinds of r ecommended protectiYe coatings for steel is being
determined in exposure tests conducted at the Division on an experimental wing spar which had
been coated with various cor rosion-resistant materials such as zinc and cadmium plate with and
without spar varnish, Indian Red in linseed oil, pyroxyline fini shes, aluminized varnish, and coal
tar paint similar to that recommended by the Naval Aircra ft Factory. The spar is built of st!:'.el
tube, girder type construction, with one chord member of cluralumin tube and the other of steel
tube. Inside, the tubing is protected in various ways recommended by the Division, namely ; lin­seed
oil , slushing compounds, aluminized enamel, and I ndian Reel in linseed oil. Altho the test
has been under way for only a short time, one fini sh. an asphalt base paint named "Et ernium," has
fa iled and the unprotected portion of the spar is badly corroded. Observations will continue over
a suffi cient period to establi sh the relative merits of these substances to inhibit cor rosion.
Universal Cup Grease for Aircraft.
In order to obviate the difficulties experienced wi t h using di ffe rent kinds of commercial greases
on aircraft parts, an investigation w:is made to fi ml a universal cup grease that would be satisfac­tory
for all purposes for which cup grease is used on airplanes. To thi s encl several samples of
grease were tested in the laboratory to determine their characteri stics under both high and low
temperatures while others were di stributed to the Wright F ield Sen ·ice Section for service tests. One
kind of grease was found which possessed sati sfactory properties as an universal cup grease and
which could be used for such parts as synchroni zer s, superchargers, instruments, landing wheels
and all places having Alemite fittings without caus ing malfunctioning of these mechani sms. Speci­ficat
ions for thi s grease which will be designated "Aircra ft Grease" will be prep<'. red as soon as
the results of the service tests art> known.
NEW BOOKS AND DOCUMENTS
DATA ON AERONAUTICAL DEVELOPMENT IN UNITED
STATES AND FOREIGN COUNTRIES ADDED TO TECH­NICAL
FILES OF THE ENGINEERING DIVISION, U. S .
ARMY AIR SERVICE.
DOCUMENTARY DATA ON INTERNATIONAL AERONAUTICS.
Document numbers rifer to Engineering Division file reference
Great Britain.
Air estimates for Grea t Britain for fi scal
year 1925 and 1926. England. Feb. 24,
1925 3 P.
Compilation of service pay of British a ir
force, army and navy, shown in daily rates
with difference between t he air force pay
and navy pay and the air force pay and
army pay, designated in percentages. Mar.
2.4, 1924. 2 p.
Appropriation account of sums granted
by parliament for air services for year
ended Mar. 31, 1924. together with reports
of comptroller and auditor general thereon
and upon the store account of the air
services. Great Britain. Mar. 12, 192fi.
92 p.
Report from select committee on Air
M"inistry Croydon airdrome extension bill,
togethe>r with proceedings of committee and
minutes of evidence. Mar. 31, 1 925. 8 P .
Roya] air force as a career. Air Ministry.
1925. 65 p. Illus.
Li st of principal active aircraft factories
in Great Britain. England. Jan. 6, 1925.
1 p.
Development at t he DeHaviland Aircraft
Works . Des cription of DeHaviland 60 and
54 England. Mar. 4, 1925. 3 p.
Report on Fairey Aviation Company, Ltd.
England. Mar. 28, 1925. 4 p.
Information regarding methods employed
b y Royal Canadian a ir _force in keeping oil
and water in airplanes warm in winter; by
Capt. J. S. Scott. Dept. of National De­fence.
Canada. May 20, 1925. 2 P.
Report on visit to Hawker Engineering
Company, Ltd England. Mar. 12, 1925. 3
p. diags .
Germany
Luftfahrt-Technesche Nachrichten. In
German. Feb., 1925. 16 p. illus .
Contents :
1. Fifteen years of Albatros.
2. Dornier-Wal flying boat.
3. Dornier airplanes in Japan.
4. New world records.
5. Dornier in Japan.
Italy.
Italian areonautical calendar for 1925.
Mar. 18, 1925. 1 p.
Review of aeronautics throughout the
world. In ?tali.an. Notiziario di Aero­nautica
No. 2 Feb., 192 5. 271 p. Illus.
charts .
Translated Contents:
Air pressure diagram in static calculation
of aircraft; by Guiseppe Albenga.
Review of aeronautics throughout the
world. In Italian. March, 1925. 286 p.
Illus.
A00.3 /58
B.41 /3
A00.3 /59
Fl 0.3 /7
C51.1 /24
F35 / 106
D52.1 /l
DeHaviland
60
F35I109
D52.416/20
F35 / 107
AlO /56
D52.03 /84
D00.12 /78
1925-No.
D00.12 /78
1925- No. 3
Review of aeronautics throughout t he
world. Jn Italian. Apr., 1925. 286 p. Illus.
Japan
Annual aeronautical report on Japan. Jan.
15, 1925. 38 p.
United States
United States Air
for fiscal year 1926.
P.
Service appropriation
Cat. Apr. 10, 1925. 1
Part played by army and navy air services
during war; by Gen. Niessel. n. d. 4 p.
Something about Me Cook Field; by T. C.
McMahon. Aero diges t. Feb. 12, 1925. 15
]).
IIistory of organization and activities of
Airplane Engineering Division and Bureau
of Aircraft Production ; by Capt. H. H.
Blee. Cat. Apr., 1925. 92 p. Photographs.
History of Lang ley Field; by Capt. H. H.
B lee. n . d. Photographs.
European commercial aeronautics; by J. P .
Van Za ndt. National Advisory Committee
for Aeronautics. May, 1925. 14 P . Map.
Boll weevil control by airplane. Georgia
State College of Agriculture. Bulletin No.
301. Nov., 1924. 22 p . Illu s .
Report on dusting experiment, 1923, u s ing
small airship; by D. F. Barnes . Oct., Nov.,
1923. 19 p. Diags .
Naval aircraft carriers of the world. Cat.
June, 1925. 1 p.
National conference on utilization of fore st
products , held Nov. 19, 20, 1924. Dept. of
Agriculture. Apr., 192 5. 100 P. Illus.
Extracts from annual report of the office
of Chief of Air Service to t he Secretary of
War. No v., 1924. 9 p.
Money expended by United States air
service for airplanes and engines. Secretary
of W ar, F eb. 19, 1925. 3 P.
Fores t Products Laboratory Progress re­port
for year 1925 .
Annual reports of the Navy department.
1924.
Month ly report o f revenue and expendi­tures
of the air mail service. Mar., 1925.
Work being done at Bureau of Standards .
Apr. 10, 1925. 16 p.
Work bei111g done at Bureau of Stan­dards.
May, 1925. 8 P.
New publications of the Bureau of Stan­dards.
Feb. 28, 1925.
Report of national screw thread com-mission.
revised, 1924. Bureau of Stan-dards.
Feb. 11, 1925. 172 p.
D00.12/78
1925-No.
AlO /13
Japan
A00.3 /32
C70/3
AOO/n2
C21/22
Fl0.3./6
Al0.01/47
D52.2 /8
D52.2 / 11
D53.15/5
Dll.l /317
D00.12 /216
A00.3 /57
D00.12 /99
1925
Mar.
C30.2/l
El0.2 /43
1925-Mar.
D00.12 /9 6
T. N . B.
D00.12/97
T . N. B.
A48.2 /119
1925
D00.12/218
30 T E C H N I C A L B U L L E T I N N o. 43
Competit1ions, Exhibitions, Records, Etc.
Rules and regulations for Beaumont cup
race. In French. Feb., 1925_ 2 p.
Italian factories engaged with construc­tion
of racers for Schneider Cup comp~tition.
Italy. Mar. 2. 1925. 1 P. · · ·
Squadron commander de Bernardi flying a
Fiat CR! lowered world speed record for
airplanes with useful load. Italy. May 8,
1925. 1 p.
Report on round-the-world flight; by Lt.
L. H_ Smith. Cat. Apr., 1924 ... 14 P .
Round the world fligh t."' In French . Cat.
Apr. 14, 1925. 30 p. Illus. map
Characteristics of airp lanes and seaplanes
exhibited at Paris aeronautical salon, Dec.
5-21, 1924; compiled by J. J Ide. National
Advisory Comm.ittee for Aeronautics. Dec.
9, 1924. 1 P .
Third exposition of demonstration and
propaganda by Under. Se.cretary for Aero­nautics
. In French. Paris . Dec. 5, 1924.
-14 p. Illus.
' "M.ilitary Zenith" C>f the Zenith car­buretor
company. A flying meet to be held .
for three successive years. Cat. May, 1925.
5 p.
Bulle.tin of Federation Aeronautique In­ternationale
for Dec. 192.4 and Mar_, 1925.
AERIAL NAVIGATION.
Principles of long distance air navigation;
by R. W. Willson a n d M. D . Hersey. Ameri­C-
an Society of Mechanical Engineers. Dec.
1922 44 p. Diags.
Remarks on aerial navigation and his ex­periences
with the rig id airship ZR-3. Hugo
Eckener. Oct. 16, 192,4. 11 p.
Some medical aspects of air transport;
by Lt. Col. C. B. Heald. Royal Aeronautical
Society. Mar. 5, 1925. 5 p.
Lighting arrangements for nigh t flying at
Croydon .airdrome. England. Dec. 15, 1924.
4 P.
INSTRUCTION
Course in aircraft armament, Air Service
Engirneering School. McCook Field. Cat.
Apr., 1925. 14 p.
Basic principles of attack aviation, Air
Serv ice Training Regulations 440 -1 45. Mar.
2, 1925. 9 p.
Bombardment aviation. Training Regula­tions
440-95. Mar. 2, 1925. 11 P.
Basic principles of pursuit aviation . Air
Service. Training Reg ulations 440-70. Mar.
2, 1925. 11 p .
RESEARCH
Aerodynamics
Resume' of advances in theoretical aero­nautics
made by Max M. Munk. National
A<lvisory Committee for Aeronautics . By
Joseph S. Ames. 1925 46 P.
Contents•;
L General principles of hydrody­namics.
2. Problems more specially concern-ing
airships. .
3 . Problems more specia lly concern­ing
airfoils and airplanes.
4. 'Propeller theory.
Visit :. to aero dynamical institute at Gottin­gen
University, Germany ; by E. N. Fales.
Sept. 1_2 -1 6. 1924. Large document, charts,
drawin.gs .
Facts and opinions on aerodynamics and
design; by prominent Italian engineers. Mar.
27, 1925. 7 p.
Reports of Italian Aeronautical Engineer­ing
and Construction Division. In Italian
w it h t ranslation. Jan . 15, 1925. 30 p .
Illus. drawings.
Contents:
1. Installation of photographic
cameras on airplanes; by Lt Col.
Cesare Antilli.
D52.03/85
F35/105
C71.61/62
C71.61 /61
C71.6/78
52.1/38
Misc.
French
A00 .7 /L6
D52.411 /145
D00.12/178
Dec., 1924 &
Mar., 1925
A40.3 /30
A40.3 /29
B60/9
Fl0 /47
D70 /76
C71.7/ll
D71.8 / 14
C71.7/10
Al0.2 /171
F32/20
Al0.2 / 173
D00.12/215
1925-No. 1
2. Thrust and power coefficients for
propellers functioning with air­plane
stationary on ground ; by
Maj. Luigi Bondi.
3 . Characteristics of sensitive emul­s
ions with respect , to aerial
photography; by Capt. Enrico
Zovatiero.
4. General plan for .installing of
pneumatic chamber at Montecello
aviation field for psycho-physio ­logical
tests of aviator s.
Reports of Italian Aeronatuical Engineer­ing
a n d Construction Division. In Italian
with translation. Feb. 15. 1925. 19 p.
Drawings _
1.
2.
Contents:
Project of 450 h. p . aviation
turbo and motor; by Italo Raf­faeli.
Sanitary a ircraft;
Apolloni.
by Giovanni
Reports of Italian Aeronatuical Engineer­ing
and Construction Division. Mar., 1925.
4f p. Illu s . drawings .
Contents:
1. · Reminiscences of sea aviation; by
Alessandro Guidoni. (Trans-lated).
2. Determination of variations of
climbing time and practical
ceiUng in correspondence w ith de.:.
termination variation s of weight
3.
4.
5.
f:i.
of machine and power of engine;
by A. Rota.
Reduction to standard air of r e ­s
ults of climb tests of a ircr aft;
by A . Rota.
Determination of geographical
position of aircraft in flight; by
N iccolo Galante. (Translated.)
Calculation of condenser of water
vapor contained in exhaust gases
of aviation engines. (Translated).
Change-plate systems in aerial
photographic cameras. (Trans­lated.)
R eports of Italian Engineering and Con­struction
division. In Italian with t ransla­tion
. April, 1925. 56 p. Illus.
Contents:
1. Mobile mechanical landing system
for airships; by Lt. Col. U . Nobile.
2. High a ltitude engines ; by Lt.
Col. Italo Raffaelli. Increase of
sen sitiveness of photographic
emlllsion through preliminary ex­posure;
by Eurico Zovattiero
4. Static e lasticity and breakage
tests of C. N. T. 10 observation
seaplane.
5. Aerodynamical wing characteris­t
ics.
" Magnus effect," principle of Flettner
rotor. Tr. from Zietsc h rift des Vereines
deutscher lngenieure, Jan. 3, 1925. Na­tional
Advisory Committee for Aeronautics.
Apr., 1925. 23 p_ Charts, diags .
Notes on the rotor problem. Tr. from
Zeitschrift fur Flugtechnik und Motorluft­schiffah
rt. Technical Data Section. Mc­Cook
F ie ld. Apr. 8, 1925. 21 p.
Preliminary investigation of effect of a
rotating cylin der in a wing; by E. B. Wolff.
Tr. from Rykstudiedienst voor de Lucht­vaart_
N. A . C. A. Mar., 1925. 12 p.
Diags .
Data on the "artificial sun." England.
Mar. 11, 1925. 2 P.
Spores in the upper air; by E . C. Stakman
and others. Reprinted from Journal of Ag ri­cultural
Research, Vol. 24-No. 7. May 19,
1923. 8 p. Illus
Photographic study of high voltage dis­charges;
by H. H. George and others. Pur­due
University. Engineering Experiment
Station. Sept .. 1924. 118 p. Illus. charts.
Method of determining dew points of fu ll­air
mixtures; by R . J. Kennedy Bureau of
Standards. Feb. 17, 1925. 11 ·p. Charts.
Specific h eat of superheated ammonia
vapor; by N . S. Osborne and others . Bureau
of Standards . Mar. 2, 1925. 46 p. Illus
charts.
D00.12 /2 15
1925-No. 2
D00.12 /2 15
1925-No. 3
D00.1 2/215
1925-No. 4
Al0.2 /172
Al0.2/88
D52.33 /94
D13.47 /13
D52.2 /10
A20 /49
Dll.3 /97
Dl 1.33 /39
NE \ A/ BOOKS AN D D1')CUMEi-..; TS
Slotted wing in practice; by G. Lachmann.
Tr. by Technical Data Section. McCook
Field. Mar. 1 8, 1925 . 3 p. Drawings.
Performance of future airplanes Cat.
June, 1925. 7 p. Charts . ·
Airplane performance estimates; by R.
Chadwick. Institution of Aeronautica l En­gineers.
F eb. 8, 192,4. 25 P. Charts .
Clim bing performance of airp la nes; by
Paul Brenner. Tr. from Ze itschrift fur
Flugtec hnik und Motorluftschiffahrt, Apr.
26, 1 92 4. Technical Data Section McCook
Field. Mar. 23, 1925. 15 p. Ch a.rt.
Performance of tandem systems; by H.
Glauert, Aeronautical Research Committee.
Dec., 19 22. 11 p. Charts.
Estimation of airplane performance from
wind tunnel tests on convent iona l airplane
models ; by E. P . Warner and Sbotswell Ober.
National Advisory Committee for Aeronau­t
ics. May, 1925. 18 p.
Apparatus for reducing airplane climb test
data to standard air value; by Ma j. Luigi
Biondi. n. d. 4 P.
Fluttering on s ing le- spar lower
H. Blas iu s. Tr. from Zeitscrift
technik und Motorluftschiffahrt.
1925_ Technica l Data Section.
Field, May 1 4, 1925. 14 p.
wings; by
fur Flug­Feb.
1 4,
McCook
Preliminary meas urements of distribution
of velocity of a fluid in the immediate n e igh­borhood
of a plane, smooth surface. 1924.
33 p. Charts.
Law of s imilitude for s urface resistance
of lacquered p lanes moving in a straight
1ine through water. Internationa l Congress
on applied mechanics. Delft, 1924 . Na­t
ion~.! Advisory Committee for Aeronautics.
Apr., 1925. 75 p . Charts, diags.
Res istance of plane s urfaces in a uni-form
current of air 1904 . 64 P. Charts.
drawings.
Velocity distribution cau sed by an air­plane
at the points of a vertical plane con­taining
the span; by M. M. Ivlunk. Na­tional
Advisory Committee for Aerodynau­t
ics . Mar .. 1925. , 8 p. Diags.
Effects of s hielding tips of aerofoils ; by
E. G. Reid. National Advisory Committe for
Aeronautics. 1 925. 9 p_ Illus. charts .
Measurements of lift, drag, and pitching
moment on the 1 /5 scale model of the B ristol
fi g hter with a irscrews runnings; by E. F .
Relf and L. J. Jones. Aeronautical Research
Committee. July, 1924. 20 p. Ch arts.
Some problems on lift and rolling moment
of airplane wings. National Advisory Com­mittee
for Aeronautics. 1925. 16 P. Diags .
Method for direct determination of profile
drag. Tr. from Ze itscrift fur F lugtechnik
und Motorlftsc hiffa hrt. T ec hnical Data
Section. McCook Field. Apr. 15, 1925. 7
p.
Theory of fu 11 scale determjnation of
damping in roll ; by S. B. Gates and H . M
Garner. Aeronautical Research Committee:
Sept., 1924. 14 P. Charts.
Experiments to meas ure variation, with
speed and s ize, of forces on an aerofoil of
thick section (Gottingen No. 420); by A.
Fage and W. L. Cowley Aeronautical Re­search
Committee. J·an., 1925. 13 p.
Charts .
Rolling and yawing moments due to aileron
action of a wing in horizontal flig ht. Tr.
from Zeitschrift fu r F lugtec hnik und Motor­luftscbiffahrt
, Apr. 14", 1925. Technical
Da ta Section. May 29, 1925. 12 P. Diags.
Air forces on a wing caused by pitching;
by M. M. Munk. National Advisory Com­mittee
for Aeronautics . Mar., 19 25. 6 p.
Determination of turning characteri s tics
of airship by means of camera obscura ; by
J. W. Crowley, Jr., and R. G. Freeman. Na­t
ional Advisory Committee for Aeronautics.
1925. 8 P. Illus.
AirfoHs, etc.
. Systematic test of J oukowski ae'!ofoils;
by J. Acke r e t. Tr. from Ze itsc hrift fur
F lu gtechnik und Motorluftschiffa hrt. Tech­nical
Data Section. McCook Field Mar. 2 6,
1925. 11 p. Charts.
D52.33 /9 1
D 52 .1 /164
D00.11 / 153
D00.11 /154
D00.12 / 949
R. & M.
D00.11 /155
D00.11 /152
D 52.33 /99
Al0.2 / 176
Al0.2.4 /7
A40.2 /12
Al0.2 / 170
D 52.338 /224
D00.12 /937
R. & M.
D 52.33 /96
D i\2.338 /223
D00.1 2 /938
R. & M.
D00.12 /935
R. & M .
D 52 .322 / 14
D52.33 /95
AlO.l / 1,4
D i\2.338/221
Air forces on airfo ils mov ing faster than
sound. Tr. from Zeitschrift fur Flugtechnik
und Motorluftsc hi ffa hrt , Feb. 14, 1925. Na­tional
Advisory Committee for Aerona utics.
June, 1925. 8 P. Charts.
Aerodynamic characteristics of a irfoils at
hig h speeds ; by L. J. Briggs and others.
National Advisory Committee for Ae ronau ­tics.
1925. 17 P. Ch art s.
T est of four t hick aerofoil s , R. A. F . ::H>.
3 1, 32, and 33; by F. B. Bradfie ld a nd A . S.
Hartshorn. Aeronautical Research Commit­tee.
Sept_, 1 ~24. 7 p . Charts.
Characteristics of single float seaplane
during t a k e -off; by J. W. Crowley, Jr., and
K. M. Ronan , N a tional Advisory Committee
for Ae ronau t ics. 1925. 11 p. Ill us . c harts .
Air force and moment for MC-08 a irs hip.
Navy yard. Con struction dept Feb. 9, 1925.
12 p. Photog r aphs, c harts. ·
Air force and moment for Myers airfoi l.
Navy Yard Con s t ruction Dept. A}Jr. 22,
1925. 3 p. Photograph, chart, drawing;;.
Air resistance of a streamline target
s leeve. Navy Yard. Construction Dept.
Feb. 2, 1925 . 4 P. P hotog r aphs, c harts .
Effect of trailing edge flaps on S loane
and M-3 a irfoils. Navy Yard. Construc­tion
Dept_ Feb. 19, 1925. 25 p. Cha r ts.
Test in McCook Field five -foot wind t unnel
of R. A. F. 1 5, 6x36" a irfoil: by E. N.
Fales Airplane Section. McCook F ield.
Ma r. 12-24 , 1 92.4. 29 p. P hotographs,
charts.
Comparison of well-known and new wing
sections tested in variable densi.ty wind
tunnel; by G. J. Higgins. National Advisory
Committee for Aeronautics. May, 1925. 13
p. Charts.
Interference of wind channel wails on t ail­setting
to trim ; by H . Glauert a n d A. S.
Hartshorn Aeronautical Research Com­mittee.
Nov ., 1924. 9 p. Charts.
Summary of data on s lotted wings ob­t
ained in wind tunnel of Messrs. Handley
Page, Ltd., by H. B. Ir v ing and A. S . Bat­eon.
Aeronautical Research Committee. Aug.,
1924 25 P. Diags.
Experiments on wind-pressure. 1908. 58
p. Diags .
Structural Analysis and Design.
Some controversia l points in a ircraft de­tail
design; by F'. T. Hill. Low-powered
fl ying; by M. E. A. W-rig ht. Some aspects
of attempts to fly around the world; by
Maj. W . T . B lake. Institution of Aero­nautical
Engineers. England. Apr., 1923 -
H p .
Structural m ethods employed b y Schutte­Lanz
Airship Co. Tr. from Zeitschrift fur
F lugtechnik and Motorluftschiffahrt. Na­tiona
l Ad v i ~o ry Comn1ittee for Aeronautics .
May, 1925 . 71 p. Photographs, c ha r ts.
Hanrbook of strength calcu lations Ed.
9 Air Ministry. Oct.", 1924. 112 p. Charts,
diags.
Special s tress computations for airplanes.
McCook Field. Cat. June, 192 5. 6 p. Chart.
S tress of airp lane while pulling up from
div e . Tr. from Zeitschrift fur Flugtechnik
und Motorluftsc hiffarht T echnical Data
Section. McCook Field. Apr. 1 7, 1925. 26
p. Charts.
Stress analysis of Boeing GA-2 n ine foot
tread ]anding gear. Boeing Airplane Co.
1. 922. 16 P. D rawings, chart.
Load factors for airplane wings ; by A. S.
Niles, Jr. n. d. 46 p. Charts .
Static test reports, 19 2 6-1 8, furnished by
German Admira lty. Feb. 24, 1925. 11 p.
AIRCRAFT
(Heavier-than-Air)
Metal aircraft construction; by J . B.
Johnson. Cat. Apr. 3, 1925. 4 p . Photo­graphs.
Photographs of British airplanes and s ea­planes
equipped with Jupiter engines. 1925
31
D 52.338 /229
D52 .338/222
D00.12./928
R. & M.
D52.6 /2
N-9H
D 52 .7 / l
MC-08
D 52.338/226
Fl4 / 11
D 52.338/2.25
D 52 .338/228
D52.338 /227
D00 .12/947
R & M.
D00.12 /930
R. & M.
A40.21 /6
D 52.16 /51
D 52.16 /50
D00.11 / 156
D 52.1 / 163
Al 0.2 / 174-
D52.l /21
Boeing
D 52.33 /90
D 52.15 /56
D 52.16 /48
D 52.1 /4 0
Misc.
British
32 T E C H N I C A L B U L L E T I N N o. 43
Brief description of Italian service and ex­perimental
airplanes. J"an. 12, 1925. 19 p.
Photographs.
Competition for high power helicopter to
be held in Italy. Mar. 18 ,1925. 4 p.
Marking of naval aircraft. Navy Dept.
Bureau of Aeronautics . May 14, 1925. 1 P.
A via
Description of A via
llH!O. BHll and BH!G
Apr. 17, ins. 7 p.
Boeing
BHl, BH5, BH9,
airplanes . Austria,
Weights aild comments on Boeing GA-2;
by C. L. Egtvcdt. Boeing Airplane Co.
Jan. 12, 1922. 19 P.
Breguet
Development of quadrimotored Breguet
Leviathan airplane. France Mar. 17, 1925.
3 p.
C. N. T.
Italy orders one C. N. T. 6 seaplane. In­formation
on C. N. T. 6 . Italy. Apr. 27 .
1925 1 p .
DeHaviland
Leaflets describing DeHaviland Moth and
Cirrus 60 h. p. engine. Cat. June, 1g2n.
6 p. Illu s . drawings_
Dewoitine
Catalog of Dewoltine
E. Dewoitine. Cat.
drawings.
Dornier
airplanes. In Frerich.
Apr., 1925. Illu s .
Description of the Dornier Wa~ and e x­pans
ion of Scadta, German contro1led aero­tran
s port company. Venezuela. Apr. 19,
1925. 3 p . Photo; tats .
Farman
Description of Farman A2, reconnai -: sance
two s eater. Cat. Apr., 1025. 2 p . Photo­graphs
.
De scription of Farman A2 reconnaisRance
two-s eater. Apr. 20, 1925. 3 p. Photo­graphs
.
Des cription of Farman heavy weight
night bombardment airplane, type BN4.
France. Mar. 12, 1925. 2 p. Photog raphs.
Fokker
U se of Fokker and Aero airplanes to
demons trate control of airplanes at low
s peeds . Eng land. Apr. 1 7 , 1925. 8 p.
F4C
Performance of F4C-1. B ureau of Aero­nautics
. Sept. 24, 1924. 21 P.
Huff-Daland
Air service catalog on Huff-Daland AT-1
and parts furnished by manufacturers for
TW -5; com_piled by Field Service Section,
Fairfield. Ohio. Ed 1. May, 1925.
HN
Performance of HN-2 seaplane. Bureau
of Aeronautics. Aug. 4. 1924. 21 p.
Performance of HN2 landp lane. Bureau
of Ae ronautics. Oct. 15, 1924 . 21 p.
Macchi
Brief d escription of Macchi 7 and 18 fold­ing
wing seaplanes. Italy. Apr_ 14, 192 5.
1 p. Photostates, drawings.
Potez
Catalog of Potez airplanes and seaplanes .
In French. Cat. Apr. 14, 1925. 31 p. Illus.
Descr!iption of Potcz l 9BN2. France.
F e b . 27, 1925. 3 p . Photographs, photo­s
tated drawings .
SC
Preliminary trial of SC-1 airplane. Navy
Dept. Bureau of Aeronautics . Feb. 20, Mar.
13, 19 25 . 36 p. Charts.
052.1 /25
Misc.
Italian
D52.03 / 83
A81 /29
D52.l /l
A via
D52.1 / 22
Boeing
D52.41 / 5
Breguet
D 52 .6 / l
C.N.T. 6
D52.1 /2
DeHaviland
60
D52.1/13
D eWoitine
D52_6 /18
Dornier
D52 .1 /38
Fannan
D52.1 / 39
Farman
D52.1 /21
Farman
D52.1/41
Misc.
Britis h
D52.1 /3
F 4C-1
D52.1 /17
Huff-Daland
D52. 6 / 1
HN-2
0 52.1 / 2
HN-2
D52.6 I 5
Macchi
D52.1 / 20
Potez
D52.l / l!l
Potez.
D52.1 / 2
SC -1
Sikorsky
Description of Sikorsky S2.9-A all metal
transport. 1924. 4 p. Photographs.
Vickers
Few examples of Vickers post war type
airplanes Reprinted from The Aeroplane
Album. ·1924. 1 p. Illus.
Description of Vickers Vernon ambulance
airplane. Cat. Apr., 1925. 7 p. Photo-g
raphs.
Vought
Static test of Vought VE-7 wings ; by J.
B. :Flowers . Naval Aircraft Factory. Apr.
15, 1925. 9 p . Photographs, charts .
AIRCRAFT
(L"lghter-than-Air)
:Modern Zeppelin airs hips Royal airships.
Royal Aeronautical Society." Mar. 26, 1925.
5 P.
Clippings concerning B urney airship and
intervie\'-' with Comdr. Burney. England.
Mar. 9. 1925. 2 p. Clippings.
Test of model airship RS-1; by William
Hovgaard. Massachus etts Institute of
Technology. Ar. 18, 1925. 111 p. Photo­graphs,
charts.
Water model tests for semi- rigid airships ;
by 1.. E. Tuckerman. National Advisory
Committee for Aeronautics. 1925. 14 p.
ARMAMENT
Tes t to determine the declaration in a-n
airplane due to firing of synchronized guns ;
bv H. G. Ingli s . Armament Section. Mc­Cook
Field. · June 4 , 1925. 2 p. Photo­graph.
Handbook on s ynchronized Darne machine
g un. In French. 1925. .40 p .
Correspondence and descriptive circular
on Farisalle armored vest. In Italian and
English. Italy. Dec. 16, 1924. Mar. 10,
1925. 5 p. Illus
EQUIPMENT
Instruments
Nonmetallic diaphragm" for instruments ;
by H . N. Eaton and C. T. Buckingham. Na­tional
Addsory Committee for Aeronautics .
1925. 44 P. Illus. charts .
New instrument for d e termining high alti­!".
udes by hot wire method; by Octave Ottair.
Tr. from L"Aero-Sorts Apr. 9, 1925. Tech­nical
Data Section. McCook Fie ld. May 2,
1925. 2 P. Diags.
Report on Bourdon metallic manometer.
Bureau of Standards Feb. 17, 1925. 2 p.
Photographs.
Des cription of Cambridge record\ng ac~
celerometer and price list. Apr., 1925. 7 p.
Photographs.
Report on DeGuiche acoustic speed indi-cator.
Tr. from L-Aerophile, Mar. 1-15,
1.925 . Technical Data Section. McCook
Field. May 2, 1925. 2 p . Diag.
Instructions for use of Dugit optical drift
meter, model A. M. In French. Bulletin
official de la direction des recherches scien­tifiques
et _industrielles et des invention~.
Dec. 21 . 1921. Diags.
Calibration of sixteen Lovibond red
glasses ; by I. G. Priest. Bureau of Stan­dards.
Jan., 1921. 2 p .
Problem of full measurement and Je­gcription
of Schiske Konsummeter; by K. R.
H. Praetorius. Tr. from Der Motorwagon,
Mar. 31, 1925. National Adviso·ry Commit­tee
for Aeronautics. May, 1925. 4 P. Illus.
Leaflets on Telephone Manufacturing Com­pany
laryngaphone. 1924 15 p. Illus.
Information- on Telephone Manufacturing
Company marine laryngaphone . England.
Mar. 23. 192 5. 2 p.
D52.1 /1
Sikorsky
D52.1 /28
Vickers
052.1 /30
Vickers
D52.1 /23
Vought
D52.7 /13
Zeppelin
D52.7 /1
Burney
D52.7/ll
RS-1
D52. 72 /3
A70 /14
D72.1 /148
D72.5 /9
D13.3/l
Diaphrams
Dl3.3/24
Altimeters
D13.3/12
Manometers
D13.3 /9
Accelero­metei
·
D13.3 /1
Speed
Indicators
D13.3/2
Drift­meters
Dl3.l /70
D13.3 /1
Konsum­meter
A20.21 /9
A20 .21/10
NEW BOOKS AND DOC UMEN TS 33
Connection checks for polyphase watt­hour
meters; by D. T. Canfield. Purdue
Univ. Engineering Extension Service. Set.
1924. 25 p. Diags.
Circulars on the "Flus sige Gase Kiel"
liquid oxygen respirator. In German. Ger­many.
Mar. 7, 1925. 7 p. Illus.
Catalog of telephones, .telephone material
and accessories. Telephone Manufacturing
Company. 1923 -24. Large document. Illus.
Test of Negretti & Zambra radiator ther­mometer,
1s ubmitted by Engiineering Di­vision,
Air Service. Bureau of Standards.
Mar. 21, 1925. 2 p. Photograph, chart.
Volume indicator for dirigibles. Historical
outline of project. Dec., 1920-Aug. 20, 1922.
Bureau of Standards. 16 p. Drawings.
Parachutes
Parachutes for the Swedish army. Ger­many.
Apr. 27, 1925. 1 p .
Test of parachute release hooks; by N . S.
Otey. Naval Aircraft Factory. Apr. 1,
1!124. 1 p. Photographs.
Seats
Information on Hanriot adjustable pi lot's
seat for aircraft. France. .Mar. 24, 1925.
l P.
Transportation
Proposed development of tran~porcation
equipment, heavier-than-air and miscellan­eous
equipment; by -C. D. King. Equipment
Section. McCook Field. Jan. 7, 1925. 28 p.
MATERIALS
Res istance of metals to repeated static
and 'impact s tresses: by R. R. Moore. Mc­Cook
Field. Cat. Apr. 3, 1925. 22 P. Pho­tographs,
charts.
Canadian air force specifications for air­craft
materials and components. Royal
Canadian Air Force.
Fatigue of welds: by R. R. Moore. Mc­Cook
Field. Cat. June, 1925. 3 P. Photo­graphs.
Physical c haracteristics of seamless steel
tubing, A. S. s pecification 10,225-D, m :::t.1111-
factured by the National Tube Company,
EJJwood City, Penna... for the consolida tcd
Aircraft Corp.; by D. M. Warner. Material
Section. McCook Field. Mar. 21, 1925. 3
P . Photographs, charts.
Properties of streamline tubing. Curtiss
Aeroplane and Motor Co., Inc. Engineering
Dept. Feb. 26, 1925. 1 p.
Tests of s treamHne
Aeroplane & Motor Co.
Dept. Feb. 10, 1925. 2
'l'eehnical Notes-No.
1925. 26 P. Illus.
Contents:
tubing. Curtiss
Inc. Engineering
p.
207-214. Apr. lfi,
207. Glues for use with wood.
208. Reversible circulation internal
fan kiln.
2;09. Structure of a softwood.
210. Structure of a hardwood.
21 l. Strong and weak glue joints.
212. American woods for paper mak­ing.
213. Detection and relief of case hard-ening.
214. White pines.
Alloys.
Copper-aluminum alloys containing from
84 to 90 per cent copper; by H. Hanemann.
In German with translation by J. F.
Vanier. Technical Data Section. Mar. 13,
1925. 10 p. Photostats.
Alloys similar to dura1umin made in other
countries than Germany. Tr. from Zeit­schriff
fur Metallkunde, 1925. Na,tional
Advisory Committee for Aeronautics. May,,
1925. 7 p.
Normal sand cast alloys of aluminum con­taining
small amounts of silicor1; by Samuel
Daniels. Journal of Industrial and Engineer­ing
Chemistry. Cat. June, 1925. 18 p.
Photographs.
D13.6/67
Dll.331/64
A20.21 /8
D13.3/25
Thermometer
Dl3.3 / l
Volume
Indicators
D 52.9 / 137
D52.9 /136
D52.39 /182
D50/8
Dl0.1 /121
D00.15/2
Misc
D00.57 /31
DlO /215
DlO /212
Dl0/213
D00.12 /97
1925-Apr.
Dl0.15/3
Dl0.13 /14
Dl0.13/2
Cast alloys of aluminum contaiuing ~ mail Dl0.13/180
amount of magnesium; by Samuel Dan id~.
Material Section. McCook Field. Cat. Apr.
3, 1925. 15 p. Photographs, chart.<.
Alloying tungsten with alu!llinum con - Dl0.1 /122
taining 10 per cent copper ; by M. R. Whit-more
and F . T. Sisco. McCook .li"'ield. Cat.
April 3, 1925. 27 p. Photographs.
Corrosion and Inhibition.
Research information surveys on cor- Dl0.1 / 123
rosion of metals, inc., tin, lead; compiled by
H. F. Whittaker. National Research council.
1924. 116 p.
Re lative corrosion of metals: by J. B. Dl0.1 / 125
F lowers. Naval Aircraft Factory. May 1 5,
1925. 5 P. Photograph, diags_
Corros ion of some cast aluminum alloys Dl0.13 /2 04
and a method of protection; by A. C. Zim-merman.
American Chemical Society. Cat.
June, 1925. 11 P. Photographs.
Corros ion of duralumin girders on U. S. Dl0.13/111
A. "Los Angeles," by H. C Knerr. Naval
Aircraft Factory. Apr. 4, f925. 3 n. Pho-tographs.
Corrosion of duralumin channel on U. S. Dl0.13/203
S. "Los Angeles." Pt. 1. Metallographic
examination; by H. C. Knerr. Naval Ai:·-
craft Factory. Apr. 15, 1925. 2 p. Photo-graphs.
Preliminary report on protective coatin~s Dll.2 3/ 187
for electron metals ; by A. C. Zimmerman.
Materia l Section. McCook Field. Apr. ::::1,
1925.
Protective treatment of aluminu1n :ind Dll.23/188
duralumin with sodium silicate; by J. B
Flowers. Naval Aircraft Factory. Apr. 17:
1925. 4 p. Photograph.
Composition and corrosive properties of
composite modeling clay; by E. R . Irwin.
Material Section. McCook Fielil. Apr. j 0,
1925. 4 P.
Dopes, Paint, Etc.
Investigation of airplane wing dopin!~; hy
J. B. F lowers. Naval Aircraft Factory. Apr.
28, 1925. .4 P. Photographs.
Development of fast yellow for wind
cones; by C. J. Cleary. Maferial Section.
McCook Field Apr. 28, 1925. 3 p.
Fabric
Test of special design patch ; by B. H.
Hale. Material Section. McCook Field. June
8, 1925. 2 P. Photographs .
Test of various fabrics for exhauat con•
<lensers. Navy Dept. Bureau of Aero­nautics
. Mar. 15, 1925. 2 p. Photograph s.
Normal · characteristics of rubberized fab­rics,
style No. 39; by B. H. Hale Material
Section. McCook Field. May 19, 1925. 5
P. Photographs, charts.
Condition of fabric of airship OB-1; by
B. H . Hale. Material Section. McCook
Field. Mar. 31, 1925. 2 p.
Test of doped fabric from rubber of the
RS-1 , :to determine whether the dope was
applied in the proper way and the cause of
the apparent lack of bond between the fabric
a nd the dope film; by G. P. Young. Material
Section. McCook Field. May 18, 1925. 2 p.
Dead load tests on TC water model fabric;
by B. H. Hale. Material Section. McCook
Field. Apr_ 2, 1925. 6 p. Charts.
Anti-Freeze Compounds.
Determination of boiling point of :zero­foe-
alcohol mixture and re lative proportion
of these two compounds w hen used for cool­ing
of aircraft engines; by G. P. Young.
Material Section. McCook Field. Apr. 7,
l!J25. 2 p. Chart.
Gas
Purification of gas of airships without de­flation;
by R. Biquard and A. Chenu. Re­pair
of worn components by electro-deposi­tion
; by J. P. McHare. Summaries from
Science Abstracts, section B. Electrical En­gineering,
Vol. 28, part 4-No. 328. Apr.,
1925. 3 p.
DlO /217
Dl 1.23I189
Dll.2/63
D52.74 /65
D2,l.3 /95
D24.3/96
D24.32/.47
D24.32 /48
D52.7 /l
TC
Dll.332 /12
Dll.32/44
34 T E C H N I C A L B U L L E T I N N o. 43
Fuels and Lubricants.
Power alcohol from tuber and root crops
in Great Britain. Dept. of Scientific and
Industrial Research. Fuel Research Board.
1925. 37 p.
Test of Tetralin fuel dope. Navy Dept.
Bureau of Aeronautics. Apr. 25, 1925. 6
P. Charts.
Test of various fuels in Packard lA-1551
eng?.ne. Navy Dept. Bureau of Aeronautics.
May 25, 1925. 15 p. Photographs, charts.
Test of Modlin gas
combustion engines.
of Aeronautics . Mar.
tographs, charts.
producer for internal
Navy Dept. Bureau
18, 1925. 10 p Pho-
Properties of processed castor oil from
Falk and Company. Material Section. Mc­Cook
Field. Apr. 8, 1925. 3 p.
Corrosion '.Properties of some lubricating
oils; by A. C. Zimmerman. Material Sec­tion
. McCook Field Apr. 29, 1925. 5 p .
Photographs.
Test of oil purifying system for air-planes.
Navy Dept. Bureau of Aeronau-tics.
Mar. 1 5, 1925. 6 P . Photographs,
drawing, chart.
Rubber
Specifications for rubber jointing material.
(In British standard specifications for air­craft
materials and components. Apr.,
1925. Specification F. 46).
Wood
Information on Maurer process for tim her
drying. France. Apr. 24, 1925. 9 p.
Tests and Miscellaneous.
Shear tests on spruce laminated blocks to
determine shear value for large bolt. Curtiss
Aeroplane & Motor Co., Inc. Engineering
Dept. Feb. 10, 1925. l P. Diags.
Efficiency tests on cable clamps by D. M.
Warner. Material Section. McCook Field.
Mar. 27, 1925. 3 p. Photograph, diag.
Analysis of deformation of mooring
spindle of "Shenandoah;" by L. B Tucker­man
and C. S. Aitchison. Bureau of Stand­ards.
Jan. 9, 1925. 10 p. Illus. charts.
Chemical, physical and metallographic
examination of Hoffman roller bearing from
cam engine; by F. T. Sisco. Material Sec­tion.
McCook Field Apr. 22, 1925. 4 p.
Photographs.
Purlin nail rivets versus double duck bill
rivets for float construction; by N. S. Otey.
Naval Aircraft Factory. Mar. 30, 1925. 3
p. Diags.
Failure of rear engine bearer support of
Consolidated PT-1 airplane; by P . T. Sisco.
Material Section. McCook Field Apr. 24,
1925. 2 p. Photographs.
Catalog of wire and fittings manufactured
by Brunton & Sons. Scotland. 1924. ·. 12 p.
Illus.
POWER PLANTS
New Italian aviation engines in course of
construction and in project. Italy. Mar~ ·· 2.
1925. 1 p.
Breitfeld-Danek
Description leaflet on 100 h. p. Brietfeld­Danek
"'Blesk" engine. In French. Breit­feld
Danek & Co. Cat. May, 1925. 5 p.
Illus.
Leaflet giving characteristics of 10 h. p.
Breitfeld-Danek "Perun I." engine. In
French. Breit.feld, Danek & Co. Cat. May,
1925 3 p. Illus.
Dl 1.3 /100
Dll.3/98
Dll.3/99
D52.419/369
Dll .21/96
Dl 1.21 /97
Dll.21/95
D00.15/16
Misc.
Dll.1 /316
Dll .1 /315
D52.39 / 180
Da2.77 / 16
D52.419 /368
D52.39/184
D52.39 /183
D52.39 / 179
D00.17/41
D52.41 /l
Breitfeld­Danek
D52 .41/4
Breitfeld­Danek
Descriptive