Technical bulletin no. 31

              AIR
VOLUME IV
(AVIATION AND AEROSTATION)
BY DIRECTION OF CHIEF OF AIR SERVICE
DECEMBER, 1922 - JANUARY, 1923
TECI-INICAL BUlJLETIN
No. 31
NUMBER 381
DEVELOPMENT OF MILITARY AIRCRAFT MATERIAL FOR UNITED STATES
AIR SERVICE UNDER SUPERVISION OF ENGIEERING DIVISION.
PUBLISHED BY
ENGINEERING DIVISION, AIR SERVICE
MCCOOK FIELD, DAYTON, OHIO
1922 - 1923
McCook Field-1-5-23-1 M
•
CONFIDENTIAL
The information contained herein is confidential and therefore
must not be republished, either in whole or in part, without
express permission of the Chief of Air Service, U. S. Army.
"
CONTENTS
AIRCRAFT DEVELOPMENT ON ENGINEERING DIVISION PROGRAM
AIRPLANES
Fokker completes 10 PW-5's-Boeing Co. builds 200 MB-3A's-First production
C0-1 built by Gallaudet ................... ... ........................... .. ........................ .................. .. ... 5
Views, description and performance of Fokker C0-4 ...................................... ........ 5 to 8 incl.
Status of NBS-1 Bomber on production contracts-Erection of Barling Bomber
at Wilbur Wr,ight Field- TA-3 contract t erminated.... .............................................. 9
The new TA-5 and TA-6 airplanes-Packard Engine for Eng. Div. TW-1-Cox­Klemin
TW-2 models-First TW -3 received for test....................... ..... .................. .... 10
Designs for ambulance ail'IPlane-Preparations for 2nd Endurance Flight of T-2......... 11
First Target and Man-Carrying Gliders designed by Engineering Division.................. 12
AIRSHIPS AND BALLOONS.
Semi-Rigid RS-1 at Goodyear factorv-First U. S. M. B. (motorized observation
balloon) at Wilbur Wright Field- Erection of port3<ble mooring mast............... ... 12
Terry Mooring Mast Buffer-Gassing device for mast-Grab winch ........... ........... .. .... 13
ARMAMENT.
Ordnance Bomb Racks replaced by A. S. type-Rack for 4,000-lb. bomb-Bomb sights 13
Magnetic clutch for cannon ring mount- Wing tip flare bracket "E-2"...................... 14
ENGINES.
50-Hour test on ''W-1" engine-Flight tests of A. C. spark plugs for Liberty............ 14
EQUIPMENT.
"Airway" tests of course-finding instruments ...... ..................... ... ............... ... ..... ............... 14
Goggles from Chicago Eyeshield Co.-New Ame1;ican made Jens (Bausch & Lomb).. 15
RESEARCH AND EXPERIMENT.
RESUME' OF ENGINEERING DIVISION SERIAL REPORTS.
Pressure Distribution Over Vought Stabilizer..... .................................... ......... .................... 16
Structural Strength of A. S. Transport T-2-World's Altitude Record (Macready
9/ 28 / 21)-Performance tests on Huff-Daland TA-2 (Lawrance Engine)
Elias TA-1, Fokker PW-6 and TW-4 models, and Loening PW-2A.......................... 17
Free and Power Balloons- Aerostatic Problem's in Desigru of L/ A Craft-Captive
or "Kite" Balloon- Aerostatic and Aerodynamic Problems in Airship Design.... 18
Non-Rigid Airship Design,-Grinding of Casein Glue....... ................................................. 19
Anti-Knock Compound Affect Matenials of Fuel System-Exhaust Temperatures
on Supercharged Engines- Supercharger for Wright Engine.................... ............ .. 20
Cooling of Huff-Daland TA-2 with Curtiss Engine- Failure of Supercharger Rotor
Buckets-"High" and "Low" Compression Supercharged Liberty Engines........ 21
INVESTIGATION OF MATERIALS.
The 54x12 Straight-Side Wheel-Coating for Duralum.in-Heat-Resisting Enamel
fo r1 Air-Cooled Engines-Metallography of Ingot Aluminum.......... ...... .................... 22
New Steel Specifications ....... ....... .. ............... ........ ............... :................ .......... ......................... 23
Casting Magnesium-Zinc Alloys in Atmosphere of Nitrogen-Casting ''Elektron"
metal (illustrations) ·····························- ·· ·· ····················· ···························· ··················· ·24-25
Corrosion of Light Alloys-Structural Analysis of Connecting Rods for "W" En­gine-
Effect of Drawing Temperatures on 6120 Sheet Steel... ,.. .................. .......... 26
Machine-Sewed Seams for Wing Covering-Moisture Content of Fokker Wing
Beams-Isolated Factors in Kiln Drying-Discoloration in Walnut Lumber.­Effects
of Stains, etc., on Airplane Woods.............................. .............................. .......... 27
FOREIGN DEVELOPMENT.
FRANCE.
Metal Construction- Abandonment of Twin--Engined Airplanes.................................... 31
Views, Description and Performance of Schneider Bn3 Night Bomber .............. .. 31-34 incl.
NEW BOOKS AND DOCUMENTS.
Documents added to Engineerirug Division Files ............. ............... .................... ,.......... ....... 35
Aircraft Development-Airplanes.
FOKKER C0-4-CORPS OBSERVATION.
(L bert}' " 12" Engine) .
4
DIVISION PROGRAM
AIRPLANES
PURSUIT
Fokker PW-5 (Wright "H-2" 300-h. p. Engine).
The Nether lands Aircraft Company (Fokker), Amsterdam, HolJand , have completed their con­tract
for ten production airplanes, two of -which were received at McCook F ield, in October, for
test. The remaining eight airplanes, together with five spare wings have been shipped to Self ridge
Field, I\Tt. Clemens, I\iichigan.
Wright engines have been installed in the two airplanes at McCook Field. One airplane
equipped with the -wright "H-3" engine and DeHavi]and axles and wheels has been air-tested
and flown to Selfr idge F ield for use as a model in assembling the eight airplanes consigned to that
place and the other. in which a Wright "H-2" engine has been in stalled, was retained for perform­ance
testing which is now under way.
Boeing MB-3A (Wright "H" 300-h. p. Engine).
Performance tests are being continued on the two product-ion model airplarn~s received from
the Boeing Airplane Company, Seattle, v\iashington. Some radiator trouble has been experi enced
to the extent of preventing performance climbs being made. A new vVright engine, model "H-3"
is being conditioned, preparatory to installing it in one of these airplanes.
The new tail surfaces have passed the static t ests sati sfactorily. The elevator and stabilizer
supported an average load of 50 lb. per sq. ft. and the rudder and fin an average load of 45 lb.
per sq. ft. without fai lure.
The last twenty-one airplanes built by the Boeing Company on this contract were assigned to
Kel ly Field, Texas. All of the two hundred airplanes have been construc ted and accepted, thus
completing the contract.
OBSERVATION
Engineering Division C0-1 (Liberty "12" Engine).
The first of the three production airplanes under construction by the Gallaudet Aircraft Cor­poration,
East Greenwich, R . I.. has just been completed. The construction of the first article
which was scheduled for delivery last November was delayed on account of the inability to ob­tain
the necessarv materials and equipment on schedul e. Delivery will be made to McCook Field
where tests will be conducted.
Fokker C0-4 (Liberty "12" Engine) ,
During a visit to the Fokker factory at Amsterdam, Holland, last year, General Mitchell, As­sistant
Chief of the United States Air Service, recommended the purchase of a two-seater observa­tion
airplane designed and built by Fokker around the Liberty engine. Subsequently a contract for
three airplanes of this design, including the one recommended by General Mitchel l, which was im­mediately
shipped to the E ngineering Division for inspection and test, was awarded to the Nether­lands
Aircraft Company (the Fokker establishment) in May, 1922.
5
Aircraft Development-Airplanes.
In August, 1922, a second contract was placed with the above-mentioned company for the
constrnction of five airplanes to be built in accordance with the modifications to be incorporated in
the last ~rticle of the first contract. The second contract provided also for the construction of
a skeleton model for use in static tests. The results of these tests which were conducted at l\k­Cook
Field were publi shed in the last number of Technical Bulletin (No. 30).
The first airplane. a brief description of which is given in this article, served as an experi­mental
model and was inspected and performance tested by the Engineering Division at McCook
Field.
The Fokker C-IV, A. S. designation C0-4, is a two-seater biplane equipped for corps ob­servation
work. In construction it i-s similar to the Fokker D-VII airplane only on a larger scale.
The C0-4 airplane was originally designed with a nose radiator but owing to the probability of
in stalling a supercharger, a provision was made for same by suspenqing two Lamblin radiators
beneath the fuselage. Either system of cooling can be used for ordinary flying. vVith the Lamblin
system, a new nose cowling and a spinner for the propeller i3 provided.
The first airplane was also provided with two distinct types of fuel supply, one in which the
main tank is enclosed in the fuselage directly behind the engine and the other in which the main
tank is streamlined in the ax le of the landing gear beneath the fuselage. This necessitates the use
of two landing gears, one of special design for holding the axle tank and the other of standard
design for use with tank in fuselage. The design permits the in,.;tallation of fuel tanks in the
wings, fuselage, or landing gear.
The fuselage structure is of the conventional Fokker welded-steel tubular type and is designed
for ease of production, maintenance and accessibilit)'. It has maximum cross-section dimension
of 42"x48". The cod.l. )its for the pilot and observer are very closely coupled as in the DH-4B and
XB-lA types, adequate provision being made for the installation of military equipment. Another
feature is the observer's seat which is arranged so as to permit its use as a high seat for manipu­lating
the guns or by a simple backward movement as a seat low enough for handling camera ad­vantageousJ
y. The engine cowling is made of aluminum .032 gage, and is supported by a special
mounting.
The tail unit is similar to the Fokker D-VII in design but is more easily assembled. Pro­vision
for adjusting the stabi lizer during flight is being made in the production models.
The lower wing is about four inches shorter in span than the· upper. The chord, however,
is much less than that of the upper. The interplane bracing consists of N-shaped steel struts at
the wing tips and a tubular tripod arrangement at the fuselage. Ai lerons are attached to upper
wing only.
All control surfaces are counterbalanced. The wmgs, fuselage, and tail surfaces are covered
with fabric.
Two landing chassis of tubular construction are provided as above stated. The shock ab-­sorber
cord is wound in such a manner that affords free play to the axle in any direction . The
tread is 6' 5 y;; ".
The power plant consists of a standard Liberty 12-A engine equipped with battery ignition and
Zenith U . S.-52 carburetors. Fuel is supplied by an air-pressure ·system, hand-operated for start­ing.
Preliminary to performance tests by this Division, the results of which are published here­with,
the Fokker C0-4 airplane was given a severe service test consisting of a round-trip flight be­tween
Dayton. Ohio, and San Diego, California, via San Francisco, a distance of approximately
5,000 miles. This flight required 57 hours and 24 minutes of fl ying time, 1,235 gallons of fuel, and
73.75 gallons of oil. The airplane was equipped with a nose radiator, and one Lamblin radiator and
an axle tank as shown in the accompanying illustration.
6
Aircraft Development-Airplanes
In the production model$ now under construction, many changes have been made to conform
to United States Air Service standards for the fabrication of fittings and other parts, standard
threads, rib-spacing in "the slipstream, method of covering. and the installation of fuel , oil. and cool­ing
systems and other equipment. The principal changes include the installation of the following:
l. Liberty l\rfodel 1921 engine with 12-volt ignition and gear-driven fu el pump.
2. Standard U. S. 36"x8" ·wheels.
3. Horizontal stabili zer adj ustable from pilot's cockpit.
4. Pilot's seat to accommodate " seat-pack" parachute.
On of the production airplanes is to be completely equipped with armament including one .30
cal iber Browning fixed gun and two .30 caliber Lewis flexible guns, in struments, radio, camera,
li fe preserver cushions, and " seat" and " lap" parachutes. Four of the production models will be
fitted with nose-type radiator s, each having a frontal area of 6.65 sq. ft. and 5-inch core whereas
the remainder will have free air or side-type radiators having a total fro ntal area of 4 sq. ft. and Air
Service standard 7-inch core for each airplane.
The production models will be delivered to Langley Field, Virginia.
FOKKER C0-4 EQUIPPED FOR CROSS-COUNTRY FLIGHT.
Showing Nose and Lamblin Radiators and Ax~e Fuel Tank.
7
Aircraft Development-Airplanes.
CRAIIACTERISTICS AND PERFORMANCE.
DIMENSIONS
Overall span ........ . ................... ... . . .. .. ....... .
Overall length ....................... ........ . . . . . .. .. ... .
Overall height ..... . ........... ... . . .... . . . _ . . ... .. . ..... .
Span ( upper wing) ..... .. ...... ............. ............ .
Chord ( upper wing) ... . ...... .... . ..... .. ... .. . . .. . . .. . . .
Span (lower wing) ...... . . . ...... .... ...... .... .......... .
Chord ( lower wing) .. . . .. .. ... ... . ... ..... . .. , ....... _ .. .
Stagger . ...... ... .............. .. ... .... .. . ..... ....... .
Gap .................... . . ..................... . . ..... . .
Incidence (leading to trailing edge) ... .... ...• . ... . .. . · ...... .
Dihedral ... .... ... .... .. . ........ . ............. . ....... .
Sweep back
AREAS
Ailerons
Elevator ....... .... ...... .... .. .. ............... . ....... .
Rudder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... .... .. .
Stabilizer .... . ...................... . . . ....... .. .... _ ... .
Upper wing ........................ . ............ .. ...... .
Lower wing ......... .. . ...... . .................... .... .. .
Total supporting area including ailerons ...... ... ............ .
WEIGHT IN POUNDS
Empty ( including water) .. . ... . ............ . .. . . .. . ...... .
r'\rn1ament ... ....... . . ......... .... .. . . ....... ...... .... .
Equipment ....... . ..... . .. . ........................... .. .
Crew ................. . ................................ .
Fuel ....... . ...... . .. . . ..... .... .. ..... ...... .......... .
Oil . .... . .. . .. . ..... · ... .............. ... ............... .
Fully loaded . ........... . ... ... .. ..... . . . ... . ........... .
Weight per square foot ........... . ............. ........ . . .
Weight per horsepower ..... . . .... .. .. ..... . ............ . . .
PERFORMANCE
CLIMB SPEED
39' 4"
29' 20"
10' 10"
39' 4" -
6' 8"
35' 5"
4' 8"
3' 4"
5' 10.7"
20
None
None
18.7 sq. ft.
23 "
10.1
17.3
272.7
144
4 16.7
2911
297
314
360
540
72
4494
10.8
11.23
Standard Time Rate Engine Level Flight Engine
Altitude 111 111111. ft/min. r.p.m. m.p. h. r. p. 111 ,
0 990 1530 130.9 1695
6,500 8.2 630 1515 127.5 1645
10,000 14.8 440 1500 122.6 1605
15,000 32.9 160 1470 108.5 1520
16,100 S. C. 41.5 100 1460 102.6 1495
17 900 A. C. 0 1445 89.0 1445
Endurancc-0 hr. at ground, 3 hr. at 10,000 ft.
Minimum speed-67 m. p. h.
PILOT'S OBSERVATIONS.
The C0-4 airplane does not taxi easily, clue to the small rudder and large fuselage and the
lack of a steerable tailskid. It takes-off normally with good climb, requiring a slightly longer run
than a DH-4B airplane at same altitude. The landing is slow with no tendency to drop out. The
airplane has the ability to "hang on" to the very last.
Stability, longitudinally and laterally. is good but on account of absence of dihedral, the
airplane must be "flown" at al_! times. Maneuverability is excellent with easy and quick response
to controls. Visibi lity is good, except forward and downward.
8
...
Aircraft Development-Airplanes
In general , the airplane gave a satisfactory performance for corps observation work. Several
structural changes, however, will be incorporated in the production model to obtain an improve­ment
in flying qualities.
BOMBARDMENT
NBS-1 (Two Liberty "12" Engines).
Three contracts were awarded for the construction of A. S. Type XII, production model
NBS-I airplanes. The fir st contract for 50 airplanes from the Curtiss Aeroplane and Nfotor Cor­poration,
New York, and second for 35 airplanes from the L-\\'-F E ng ineering Company,- New
York, are Engineering Division projects, whereas the third contract for 25 airplanes is under
supervision of Chief of Air Service. The status of construction on these contracts is as follows:
Curtiss NB S-1.-Twenty-seven airplanes have been accept eel by the Government and shipped to
their destination. Con;-;tru ction on the entire contract is more than one-half complete. The hrst
of the twenty airplanes to be equipped with supercharged engines is expected at McCook Field
shortly.
L-W-FNBS-1.-This contract is nearing completion with the acceptance of i:he twenty­eighth
airplane by the Government. Twenty-three airplanes haYe al ready been shipped.
Arromarine N BS-1.- The Aeromarine Plane and Motor Company, Keyport, N. J., has
started construction on a contract for twenty-five production NBS-1 airplanes awarded by Chief
of Air Service. The fir st airplane, patterned after the L-W-F model. is nearing compktion and
shipment of the necessary equipment for in stalltion in this ai rplane has been requested by the
contractor.
NBL-1 (Six Liberty "12" Engines).
The Vhtteman Aircraft Corporation, Hasbrouck Heights, New Jersey, is completing the con­struction
of two landing chassis and six wing panels for the Barling Bomber. All of the other
units have been received at the Fairfi eld Air Intermediate Depot, vVilbur \Vright Field, Ohio, for
assemblv. A careful estimate of the total weight of the airplane assembled for fli ght with full load
is placed at 40,744 pounds.
The assembly and erection of this large ai rplane presents quite a problem owing to inability
to house the structure in the ordinary U. S. Army hangar. One plan submitted by Mr. Barling,
the designer, proposes the partial erection of the airplane within the hangar by assembling the
fuselage, the lower wing structure, empennage. nacelles, power plants, and other minor units. The
landing gear wheels, upper wing, and outer wing panels are to he assembled after the airplane is
brought outside of the hangar. It has not been definitely decided whether this work will be clone by
the Government or by contract.
TRAINING
Dayton-Wright TA-3 (LeRhone Engine).
The contract with the Dayton vVright Company, Dayton, Ohio, for the construction of three
experimental side-hy-sicle seater training airplanes, A. S. Type XIV, has bee1) terminated.
The fir st airplan e. vie\,·s and pet formance of which wer(' published in Teclmi..:al Orders ~'o.
23, nas equipped with an 80-h. p. LeRhone engine. It was perf,w;nance tested at McCook Field
prior to static testing. Performance tests have not been completed on the second and third air­planes
on account of the trouble experienced with the 110-h. p. LeRhone engines with which these
airplanes were e<1uipped. This difficulty is evidently clue to the fact that the fuel-head resulting
from the gravity feed is greater than that used on rotary engines ordinarily. The pressure of this
fuel-head against the sensiti\·e adjustment on the fuel-metering valve causes too strong a fl ow of
fuel against the needle Yalve, thereby causing poor adjustment of the mix ture. Changes in the fuel
system are being made to overcome this t rouble.
t
9
Aircraft Development-Airplanes.
Dayton-Wright TA-5 (Lawrance "J-1" 220-h. p. Engine).
Only one airplane of this model is under construction for this Division by the D:iyton V; rigbt
Company, Dayton, Ohio. The contract was awarded in September, 1922. This airpla!1e is to be
similar in construction to the Dayton ·wright T A-3 models with the exception of the power plant,
which is to be a Lawrance "J-1'' 220-h. p. rndial engine, and a change in the area and stagger of the
wings. The construction and engineering work is over one-half completed.
Huff-Daland TA-6 (Lawrance "J-1" 220-h. p. Engine).
The firm of Huff-Daland and Company, Inc., Ogdensburg, N. Y., are constructing one ex­perimental
training airplane, A. s·. Type XIV, on a contract awarded by the Engineering Division
last October.
This airplane. designated model TA-6, is similar in design to the Huff-Daland T A-2 model,
the priucipal differ~nce being in the substitution of a Lawrance radial engine of greater horsepower
and the use of metal construction for the fuselage and wing structures.
The construction of the airplane is over one-half complete. The engine has been shipped from
McCook Field to the H uff-Daland factory, where the acceptance flights will be conducted.
Engineering Division TW-1.
The performance of the T\V-1 airplane equipped with the Liberty "6" engine was not entirely
satisfactory for the reason that the airplane appeared to be under-powered. In an effort to improve
this performance, the Engineering Division ,has recently completed the installation of a 300-h. p.
Packard model "lA-123T' engine in this airplane. Incidental flight tests will be conducted in the
near future.
Two airplanes of this model were designed and constructed hy the Engineering Divi sion. Views
and performance of the flight test model were published in Technical Orders No. 23.
Cox-Klemin TW-2 (Wright "I" 150-h. p. Engine).
The Cox-Klemin Aircraft Co., Inc., College Point, N. Y., are building three experimental train­ing
airplanes, A. S. Type XIV, for the Engineering Division.
The first airplane was received at McCook Field jn Apri l, 1922, where it passed the static
tests with fairly satisfactory results. The second airplane, the flight test model, arrived in Oc­tober,
1922. This airplane was equipped with a \i\Tright Moclel "I" 150-h. p. engine which did
not develop sufficient horsepower to give a satisfactory performance on the tests flights. This en­gine
was subsequently replaced by a Wright Model "E" of 180-h. p. and performance tests con­tinued.
A high speed of 99 111. p. h. was attained.
A ·wright Model "E" engine has been shipped to the con tractor for installation m the third
airplane now nearing completion.
Dayton-Wright TW-3 (Wright "I" 150-h. p. Engine).
This airplane, hyo of which are being manufactured by the Dayton-Wright Company, Day­ton,
Ohio, under a contract from Chief of Air Service, 'Nashington, fJ. C., is a modification of
the Dayton-'vVright T ,\-3 airplat:e, !\. S. Type Xl V, with a w:iter-coolec.! engine. Insamuch as it
is not an Engineering Division project, this Division will report only such information as pertains
to the work under its supervision. This will include all in spection and tests of the airplane carried
out by the Engineering Division.
Altho the TW-3 airplane will be similar in general construction to the T A-3 model with the
air-cooled engine, the structural changes necessa'ry to accommodate the installation of a heavier
engine of the water-cooled type and greater fuel capacity will necessitate a complete redesign of the
airplane. ·
10
Aircraft Development-Airplanes
The wing panels will have to be strengthened and increased in area to maintain the required
loading for the additional weight of the power plant. This will be accomplished by making the
upper and lower wings of equal span with corresponding changes in the interplane bracing. The
forward part of the fuselage and landing gear will be of the same construction as that used on the
TA-3 but none of the parts will be interchangeable. The rear part of the fuselage will be prac­tically
the same except that it will be two inches narrower at the front end. Two complete sets of
tail surfaces are to be constructed for the first airplane, one set of the balanced type and the other
of the unbalanced type, fhus permitting various combinations. The power plant installation is to
be designed to permit the use of any of the ·wright models, A, I, E, or E-2 engines.
The TW-3 airplane will be identical in many respects to the TA-5 model now being built by
the Dayton \~!right Company for the Engineering Division with the exception of the power plant
in stallation and controls, that is, the rear part of fuselage, tail surfaces, wings, and landing gear will
be interchangeable. The wing bracing will differ only in the 5-inch difference in stagger.
The construction of the first TvV-3 airplane was completed in January and delivered to Mc­Cook
Field for inspection and tests. Such changes as are recommended by the Engineering Di­vision
after test will be incorporated in the second airplane.
MISCELLANEOUS
Ambulance Airplane.
The development of a suitable ambulance airplane, especially designed for this purpose, ap­pears
to be very necessary for safe-guarding the welfare of the flying personnel. Previous experi­ences
with converted types have resulted in a crystallization of ideas on the design and require­ments
for such an airplane. The essential characteristics have been formulated as follows:
Usefnl load.- Pilot-180 lb., medical officer 180 lb. and two patients-360 lb. Total load-720 lbs.
E11dura11ce.-Fue1 and oil required for three ( 3) hours at full speed at ground.
Performance.-The most important performance requirernent is a slow landing 5peed around
JS m. p. h. with minimum run on ground in landing or "take-off." A high speed of
about 90 m. p. h. is considered sufficient.
An arrangement has been suggested whereby the pilot and medical officer will be seated side
by side in front with the two patients in stokes litters, placed side by side, directly behind.
The Engineering Division has completed four preliminary designs which, together with the
exhibition models have been forwarded the Chief of Air Service for approval. What appears to
be the most suitable design from a medical standpoint is the one with the Curtiss "D-12," 375
h. p. engine. However, in event this design is approved, it will probably be built around the Liberty
"12" engine owing to the large number of these engines on hand.
Air Service Transport "T-2."
Preparations are being made for another endurance flight of the Air Service T-2 Transport in
an effort to establish a record of forty hours. The flight is to be made under F. A. I. rules in the
vicinity of Dayton, Ohio, about the first of March.
The modifications to the airplane will include the installation of a completely reconditioned
Liberty "12" engine equipped with high compression pistons, stub-tooth gears, sylphon pump, and
8-volt ignition- system. A reserve tank for water will be carried and also a fluid, known as "X," for
stopping leaks in the water system. The cabin of the transport will be heated by a system of pipes
from the exhaust.
A special grade of gasoline fuel was obtained from Rockwell Field, San Diego, Cali forn ia,
for use in this flight. It is estimated that 750 gallons will be necessary, including "warming-up" of
engine before taking off.
11
•
Aircraft Development-Airplanes.
Engineering- Division Gliders ''G-1" and "G-2"
A small glider designed for use as a target for either aircraft or anti-aircraft gnns was con­structed
by the Engineering Di vision in December. T he glider which is designated model "G-1 ,"
has a span of 120 feet and a chord of 18 inches. An U.S. !\.-27 aerofoil section is used. The tail
surfaces are fixed but can he ad i usted on the ground to give the required degree of longitudinal
and directional stability. The .speed range is estimated from 18 to 45 rn. p. h. T he total weighr
is 23 pounds.
Several ground tests have been made with favorable results. A device is heing mounted
upon the upper w1ng of a Curtiss JN airplane for launching the glider in the air. Flight tests will
be conducted as soon as this work is completed.
* * * * * *
The design of the fir st man-carrying glider to be undertaken by the E ngineering Division is
under way. The "G-2" glider, as it is called, is of the parasol monoplane type using a JN upper
wing with Eiffel section o. 36. The specifications call for a span of 41 feet-3 inches, length 21
feet, weight empty of 227 pound s, and a wing loading of approximately 2 pounds per square foot.
AIRSHIPS AND BALLOONS
Semi-Rigid Airship RS-1.
A great amount of experimental work is being done on the design for the new R S -1 air­ship
by the Goodyear Tire & Rubber Company, Akron. Ohio, preparatory to starting the con­struction
of the various units. This work includ es the general layout of the ship, the design of
the structural detail s, the selection and tests of envelope fab ric and other materials, and hydro­static
and aerodynamic tests on variously shaped models.
The "RS-1" air ship is of the semi-rigid type and is designed for long range reconnaissance.
It will have a-volume of 700,000 cubic feet and will be equipped with four Liberty " 12-A" engines
especially adjusted for airship use.
U.S. M. B. Airship.
Delivery of the U. S. M. B. (United States Militarv Type B ) air ship cnnstrncted by the Air­ship
Manufacturing Company of America, located at Hammondsport, N. Y., has been made to
the Lighter-than-Air Operating Station at \:Vilbur "\i\Tright _F ield . where it will be e rected for test.
The U . S. M. B. is a twin-engined, non-rigid ail-ship and represents the fi rst attempt to motor­ize
an obser vation balloon. T he power plant consists of two 60-h. p. Lawrance radial engines. The
general characteri stics were publi shed in Technical Orders No. 23.
Portable Mooring Mast, Suspension Type.
The construction of a portable mooring mast, suspension type, has been completed and the
mast erected at the Airship Mooring Station, Wilbur · ·w right F ield, awaiting test with the Navy
T ype "H " Towing Airship. ·
The mast proper is of tubular construction with cable bracing, and is mounted on old DH -4
landing-gear wheels. which have been slightly modi fied for this purpose. T he airship is moored to
a cable running between the ends of two tubes mounted in a "V" shape upon the axle tubes, thru
a medium of a special mooring arrangement fastened into the suspension cable and equipped with
buffer bags. The wheels are mounted at right angles to the axle tubes passing thru a common
center, allowing the mast to rotate about the point of anchorage. The mast is easily dis-assembled
and is therefore very mobile.
12
Aircraft Development-Airships and Balloons
A new principle in the method of mooring airships is involved in the design of this mast in
that the ai rship is attached to the mooring mast at the mooring-post on the airship instead of at
the nose. The tests will prove or disprove its adaptability to the mooring of semi-rigid airships
and also the belief that this method will produce minimum strains in the airship.
Mooring Mast Buffer.
A buffer for attachment .to a Terry Type Mast has been constructed and delivered to this Di­vision
for test. This device is a cone-shaped buffer, which is simi lar to the original Terry Type
buffer , but which has the buffer attached to an auxiliary ring suspended inside of the outer ring oi
the cone by means of radial springs. These springs afford the compensatioi1 for turning, for ­ward,
and backward movements of the airship.
Gassing DeYice for Mooring Mas t.
· A device for inflating airships when moored to a mast has been built and is to be in stalled on
a Terry Mast at ·Wilbur \ iVright Field where the Lighter-than-Air Station of the Engineering
Divi sion is located .
This device consists of a galvanized oil-sealed chamber, one unit of which is mounted on the
upper stationary part of the mast, and the other unit ( inverted pan) to the movable part of the
mast. The gas connection is made by means of a fo ur-inch pipe, leading to the ground, and an
inflation sleeve attached to the in verted pan.
Grab Winch.
Preliminary work has been started on the design of a Grab \ iV inch for the ground-handling of
airship s, which is expected to afford the facilities for taking hold of the drag line and landing
an airship by mechanical means, thereby eliminating the necessity of having large landing crews.
ARMAMENT
BOMBING
Bomb Racks.
Further development of bomb racks to replace the Ordnanc<; bomb racks, Mark XVI and
l\fark XIX. has been abandoned in favor of the Air Service racks, Types B-2 and C-2, which are
a redesign of the Ordnance bomb racks.
* * * *
The th ircl model ( prodnction model) of the Type H-2 bomb rack for carrying the 4,000-pound
bomb has been completed.
Bomb Sights.
Flight tests are being conducted according to the principles of the open bomb sight, wherein
the altitnde. time of fa !l, drift and range errors may be observed directly.
* * * *
Due to lack of fu nd s, fnrther work on the T ype X-3 stabili ;cer for bomb sight, which was to
!,ave been made by the Lawrance Sperry Aircraft Company has been suspended.
* * * *
The development of a pilot director with an automatic turn indicator has been incorporated
in the development work of several other bomb sights.
13
Aircraft Development-Armament
The adaptation of a gyroscopic stabilizer with the (Navy) Mark III bomb rack has been
abandoned on account of its inferiority to recent sights developed by the Engineering Division.
GUNS
Cannon.
The magnetic clutch for the Type -B cannon ring mount is being redesigned to eliminate the
magnetic drag set up in one cluth during the operation of the opposite clutch mechanism.
Machine Guns.
The gun mounts for installing a Browning aircraft machine gun in the floor of a DH-4B au­plane,
in both the pilot's and observer's cockpits, are being modified for installation and tests.
* * * *
The spade grip for the .30 caliber Browning aircraft machine gun, flexibly mounted, has been
redesigned so as 'to simplify the operation of the gun and at the same time facilitate manufacture.
PYROTECHNICS.
Wing Tip Flare Bracket "E-2."
Test on the mode( "E-2" wing tip flare bracket, developed by the Engineering Division, in­dicate
that its use will give better illumination, eliminate glare, and reduce fire hazard to a greater
extent than the Holt flare bracket.
ENGINES
WATER-COOLED TYPES.
Model "W-1" 700-h. p. 18-cylinder.
One of the new eighteen-cylinder Model "W-1" engines, designed and built by the Engineermg
Division, is undergoing another fi fty-honr endurance test. An aluminum cylinder for this engine
is also undergoing te..,t.
ENGINE ACCESSORIES.
A r, Spark Plugs.
Several sets of A C spark plugs, types 35 and 35-Y, were installed in a LePere airplane with
Liberty "12" engine, three flights being made with each set of plugs. .l\t an altitude of 14,000
feet, continual fouling of the plugs w1.s experienced and the tests had to be discontinued.
EQUIPMENT
GENERAL.
"Airway" Flight Tests.
Two flights, one from Dayton to Chicago and the other from Dayton to New York, have been
recently made via "Airway" for the purpose of determining the accuracy of course-finding instru­ments.
A dead-reckoning course was plotted by observing drift a·nd ground speed. A position line
14
Aircraft Development-Equipment
was then plotted from a sextant observation on the sun. The intersection of these two lines gave
the theoretical location of the airplane at the time the observation was made. The theoretical loca­tion
was then checked with the actual location \vhich resulted in an average error of six to seven
miles.
The sextant used in these tests was the "Bunge," a German instrument that had been con­siderably
modified by the Engineering Division. Standard time was obtained from carefully cali­brated
airplane clocks. The drift and ground speed was determined by a Pioneer drift indicator,
using a stop-watch with special dial.
From the results obtained, it appears to be very difficult, if not impossible, to obtain accurate
readings in the air on a "bumpy" day by the use of an artificial horizon. Flights are being con­tinued
notwithstanding.
Wide-Vision Goggles.
The Chicago Eyeshield Company recently submitted, on their own initiative, a pair of goggles
(No. 220, Wide-Vision type) for examination and test as to their suitability for aviation use.
The goggles were well made and contained a go'od grade of glass, well finished. This glass had
been cut from a cylindrical surface and was not "non-shatterable."
On flight test, it was found that a blind spot existed forward and clown, caused bv the ex­tension
of the eye cups from the face. This blind spot interferred with a clear view of the air­plane
instruments. It was also found that the forward extension of the eye cups caused the
goggles to lift from the face when the wearer's head was turned sideways to the. slipstream. The
manufacturer was advised that these goggles were not as satisfactory as present types used by
the Air Service.
PHOTOGRAPHY
Bausch & Lomb Sample Lens.
The Bausch & Lomb Optical Company recently submitted to the Engineering Division, a
sample lens built along the same lines as the Zeiss Tessar lens. This lens was put in a testing
camera and actual photographs taken in the air. The Zeiss lens was then installed and photo­graphs
taken over the same area. The results were quite encouraging, and it is believed that
American lenses will soon be produced that will equal in quality any foreign lenses made today.
If>
RESEARCH AND EXPERIMENT
I
RESUME OF ENGINEERING DIVISION
SERIAL REPORTS.
Serial R eports 11Larked with an asterish ( *) will
be issued by the Chief of Air Service as "A,ir
S ?-n,ice I11for111afi()n Circulars."
AIRPLANE SECTION.
Pressure Distribution Over Stabilizer of Vought VE-7 Airplane. *Serial No. 2022
In the application of the theories of air flow over airplane surfaces, it is necessary for the de­signer
to employ almost exclusively the resuitant effects of air forces upon the various parts of the
airplane. This is particularly the case regarding the actual di stribution of air loads on the tail
surfaces upon which very little data are available. The results of a series of tests conducted by
the National Advisory Committee fo1· Aeronautics upon a Curtiss JN--4D airplane equipped with
a standard tail group and alsn with horizontal tail surfaces of special thick section indicate that
unrler certain conditions of flight μeavy localized loads occur which require serious consideration in
the construction of the tail group, especially in the case of the thick section which may be subjected
to great twisting forces about the "X" and "Y" axes of the airplane. Heretofore. these forces
have not always been acocunted for in the design of the tail group. The report of the N. A. C. A.
also brings out the fact that, in general, any horizontal surface is subj ected to comparatively brge
moments about the "X" axis, caused by the rotation of the slipstream.
In the in vestigation made by the E ngi11 eeri11g Division, the results of which are given in detail
in this report, the distribution of p ressure over the horizontal tail surfaces of the Vought VE-7
airplane was determined for the various conditions of flight, namely. normal flight. diving to high
speed, pulling out of dive suddenly, and stal!ing at engine speeds of 700 to 1700 r. p. m. to deter­mine
the effects of the slipstream.
The reading were taken at altitudes of about 5,000 feet on the right hand stabili zer only, by
means of 19 pressure holes arranged in four rows, two of which were placed close together near
the tip in order to explore that region more accurately. Each hole was connected to a pressure
gage mounted in the rear cockpit by two rubber tulJes, one opening on the upper surface of the
stabilizer and the other on the low~r surface so t hat each instrument indicated the resultant pres­sure
at that point. In order to obtain a reading of all pressures simultaneously, a motor-driven
motion-picture camera was used to photograph the instrument board. The camera was controlled
by a switch in the pilot's cockpit and was capable of making 106 exposures per minute.
Unfortunately, this investigation could not be carried over the entire horizontal surfaces as
originally intended. For that reason and because of other factors that were not taken into account
during the tests, it would be unwise to draw definite conclusions on the actual distribution of pres­sure.
From the data obtained, however, the indications were that the average loading is not as
high as it is generally supposed. _On the other hand, the local intensities along the leading edge
reach very high valnes requiring carefui design in the front spar and in the leading edge of a hori­zontal
tail surface.
16
Research and Experiment-Serial Reports
Structural Strength of Air Service Transport "T-2" *Serial No. 2031
Preparatory to the attempted t ranscontinenal non-stop flight of the Air Service Transport
"T-2," an investigation was made at McCook Field to determine the structural strength of the
wing cellnlne and the landing chassis under the conditi ons of loading for this flight. The report
contains an account of t he static test of the wing, the stress analyses of the wing cellule and
landing chassis, and a brief description of their structural characteristics.
FLYING SECTION.
World's Altitude Record Flight of LePere U.S. A. C-11 Airplane
Equipped with Supercharged Liberty Engine.
(Lt. Macready- September 28, 1921. )
Serial No. 2041
This memorable flight which proved to be the vVorld's altitude record was primarily under­taken
for the purpose of determining the absolute cei ling of a supercharged airplane ancl repre­sented
a real test of the development of the supercharger.
The report gives a complete account of the flight made on September 28, 1921 , by Lieut. J. A.
Macreacly, Air Service p ilot, at McCook F ield , Dayton, Ohio, in a LePere airplane, A. S. type V,
equipped with a standard Liherty "1 2" eng-ine and Moss supercharger. lt includes the per form­ance
results, brief description of the airplane and the power plant, a discusion of the in stru­ments.
data. and altitude determinations by the Bureau .of Standards, and the personal experiences
of the pi lot with photographs of the airplane and the supercharger in stallation.
Performance Tests.
This Division has completed per fo rmance tests on the following experimental airplanes. T he
standard report contains a summary of results, weight schedule, performance curves, brief de­scription
and photographs of the airplane, description of the power plant, and the pilot's observations.
Huff-Daland 'I'A-2 with Lawrance "R-1" Engine. *Serial No. 2042
This is a two-seater training airplane, A. S. type XIV, built by the Huff-Daland Co. , Inc., of
New York. It is powered by a 9-cylindt>r, air-cooled Lawrance radial engine. Views, description,
and performance of t his model were publi shed in T echnical Bulletin No. 2S.
Elias TA-1 with Lawrance "R-l" Engine. *Serial No. 2043
The Elias TA-1 was manufactured by the G. E lias & Bro. Inc .. of Buffa lo, N. Y., and is a
two-seater training airplane, A. S. type X IV, equipped with a 140-h. p. Lawrance radial engine.
the same model as that used in the H uff-Daland TA-2 airplane. Views, description, and per­fo
rmance results were publi shed in T echnical Bulletin No. 29.
Fokker PW-6 (D-IX) with Wright "H-2" Engine. *Serial No. 2044
This airplane is a single-seater, A. S . type I pursuit biplane, formerly designated "Fokker
D-IX." purchased from the Netherlands Aircraft Manufacturing Company, Amsterdam, Holland.
Views. description, and per formance data are given in T echnical Bull etin No. 30.
Fokker TW-4 with Curtis "OX-5" Engine. *Serial No. 2045
This model which was purchased from the Netherlands Aircraft Manufacturing Co., Amster­dam.
Holland, is a two-seater, A. S . type XV training a irplane, views, description, and performance
of whi ch were publi shed in T echnical Bulletin No. 30.
Loening PW-2A with 1Wright 300-h. p. Engine. *Serial No. 2065
The Loening experimental model P\V-2A constructed by the Loening Aeronautical Cor­poration
of New York is a single-seater, A. S. type I pursuit monoplane, a complete account of
which is given in T echnical Bulletin No. 28. This model has gone into production and will be
known as a production "P\i\T-2."
17
Research and Experiment-Serial Reports
LIGHTER-THAN-AIR SECTION
The Evolution of Free and Power Balloons.
(Appendix "A")
Serial No. 2058
This paper was originally prepared for the Airship Engineering Society of Dayton, Ohio. It
gives a brief history of the evolution of passive balloons, commonly known as "Sphericals," and the
pre-war development of power balloons or airships of the non-rigid and semi-rigid types in for­eign
countries. The rigid types are not discussed herein as a separate paper will be required on
this subj ect.
In this report, Part One on "The Evolution of Free Balloons," is written in chronological
order with no regard to the country in which the event took place, whereas Part Two on "Power
Balloons or Airships" treats the developments in France, Germany, Italy and England in chrono­logical
order. The absence of American developments in this paper was desirable at the time of
preparation; a revision is now under way which will incorporate these important developments.
Aerostatic Problems in Design and Navigation of Lighter-than-Air
Craft without Power (Lecture No. 2). Serial No. 2059
This report is written in the form of a lecture on the aerostatic problems involved in the de­sign
and naYigation of free balloons and the practical effects produced by atmospheric and other
conditions. The subj ect is discussed under four divisions as follows:
1. The principle of bouyancy as applied to lighter-than-air craft.
2. The spherical free balloon.
3. The effects of atmospheric changes on the free balloon.
4. The relation between volume or li ft and altitude.
Several charts on atmospheric conditions and formulas used in the solution of the problems
are appended.
The Captive or "Kite" Balloon (Lecture No. 3). Serial No. 2060
In this lecture, the problems invoh·ed in the design of a captive balloon, the study of the equi­librium
of the retaining cable, and the effects of wind pressure are di scussed. The evolution and
study of the forms of the captive balloon ::ire treated from the inception of the first elongated bal­loon,
the German "Drachen," to the more recent French "Caquot" and Italian "A. P." types.
Appended to the report is a problem in observation balloon design and several tables giving
the relative strengths of steel cables and of Italian hemp and Manila rope.
Aerostatic and Aerodynamic Problems Involved in Design of
Airships (Lecture No. 4) Serial No. 2061
In this report, a study of the problems involved in the design of airships and the methods em­ployed
for their solution is taken up under six different subj ects as follows:
I. Carrying capacity or net li ft.
1. Static lift or bouyancy.
2. Variation of static lift with altitude.
II. Dynamic lift of an airship.
III. Stability of airships.
1. Yawing moments and coefficients of stability.
IV. Control of airships.
1. ComparatiYe data on relative areas of control surfaces for various airships- Table I,
Charts I and II.
V. The drag effect of the resistance of airships in flight, its influence on speed, and the re-lation
between speed and altitude.
1. Resistance in general.
18
Research and Experiment-Serial Reports
2. Resistance of variously shaped bodies.
3. Resistance of fusiform or streamline bodies and airship envelopes.
4. Total resistance of a completely rigged airship.
VI. Appendix.
1. Chart I and Table I, covering a discussion of adiabatic temperature change
2. Charts II to V, show-ir>g yearly and seasonable variation of atmospheric pressure,
temperature, vapor pressure, and densitv with altitude.
3. Table II and Chart VI, showing static !ift of pure hydrogen in dry air at various pres­sures
and temperatures.
4. Table III and Chart VII, showing per cent of envelope fullness to attain a given
height at complete fullness or the loss in static lift at a given ,height with initial en­velope
fullness.
5. Charts VIIT and IX, showing variation of engine performance with altitude.
6. References.
Non-Rigid Airship Design (Lecture No. 5) Serial No. 2062
This lecture presents the subject of the design of non-rigid airships in a very concise logical
manner. It is divided into parts for convenience. Discussion of the semi-rigid and rigid types
of airships is to be taken up in subsequent lectures.
A brief• outline of the contents of this report is as follows:
I. Elementary parts of an a irship.
II. Types of airships.
1. Astra-Torres (French).
2. Parseval (German).
III. Factors of safety.
1. American practice.
2. Italian practice and Forlanini types.
3. French practice.
IV. Non-Rigid envelope design.
1. Shape of envelopes.
2. Position of ballonets .
.3. Position of control plane£.
4. Envelope and cable stres£es.
5. Rigging.
6. Nose stiffening.
7. Valves.
V. Problems.
VI. References.
VII. Appendices.
1. Sur face area coefficients.
2. Cable resistances.
3. Nose stiffening.
4. Charts on Characteri stics of Airships.
MATERIAL SECTION.
Fineness of Grinding of Casein Glue. Serial No. 2032
In this investigation, it was found that the grinding of commercial casein glue to finer pro­portions
than those used in present practice did not improve the strength properties to any appre,i­able
extent as previonslv supposed. lt was apparent from the obsen-ations made during the tests
that the strength of the glued joint depended more upon the amount of gl ne applied and the lP.ngth
of time which elapsed between the application of the glue and the application of the pressure to
form the joint than upon the fir.eness to which the glue was ground. Further investigation of this
phase of the subject is contemplated.
19
Research and Experiment-Serial Reports
Effect of Anti-Knock Compounds on Materials of the Fuel System.
(Anti-knock Compounds No. 500 and 501).
Serial No. 2078
The Engineering Division has completed several investigations on the corrosive effects of vari­ous
doped fuels, such as Anti-knock No. 1, monoethylanaline, and other similar compounds on the
materials used in the construction of fuel systems. The data contained in the report apply only
to Anti-knock compounds No. 500 and No. 501, the former being a more highly refined prod~ct.
The results of the experiments extending over a period of three months showed that these
compounds do not cause corrosion of the materials used in the fuel system, in fact, they apparent­ly
inhibit corrosion to some extent. Both of these compounds when mixed with motor gasoline
or aviation gasoline and exposed to light, caused the formation of sediment, presumably lead oxide,
regardless of the kind of material immersed in the fuel. The Anti-knock compound No. 500
caused the formation of sediment with motor gasoline even when not expooed to light except in
cases where leather, cork, or textoil are present. The results of exposure of these compounds pro­hibit
their use unless some modifications are made to prevent the decomposition and precipitation
of lead compounds.
POWER PLANT SECTION.
Variation of Exhaust Temperature with Mixture on Supercharged
Liberty "12" Engine. Serial No. 2021
A series of ground tests was run at night on a General Electric Form "D'" supercharger at­tached
to a Liberty "12" engine in ;:i. DH-4B airplane to determine at various carburetor settings
the probable temperatures of the exhaust gas in which the rotor and buckets of the supercharger
operate.
A thermo-couple was inserted in the nozzle-box of the supercharger and the temperatures of
the exhaust gases were measured on a multi-volt meter. Check readings were obtained on various
hot parts of the manifolds and nozzle-box by means of an optical pyrometer. During each run
photographs of these parts were taken. These photographs show very clearly the increase in ex­haust
gas temperatures as the mixture was "leaned out."
The results of these tests were used in an investigation to determine the causes of failure of
supercharger rotor buckets discussed in Serial No. 2030 following.
Development of General Electric Form "C" Supercharger for Wright
· 300-h. p. Engine. Serial No. 2027
This report gives an account of the development of a turbo-supercharger, known as Form
"C," for adaptation to a V/right Model "H" engine. This supercharger is similar in design to
the Form "D" supercharger used on the Liberty engine. Two units were built by the General
E lectric Company and in stalled on airplanes at . McCook Field, one on a DlI-4B\iV and the other
on an Orenco "D", both of which were equipped with Wright 300-h. p. engines. A photograph
of the latter installation is shown on page No. 8 of Technical Bulletin No. 27.
A series of flights were conducted with highly satisfactory results in greatly improved per­formance
at altitude. The following table gives a comparison of the performance of the Orenco
"D" airplane with and without the supercharger.
Time of climb to 20,000 feet ............. .
Speed at 20,000 feet .. . . ........... ..... .
Absolute ceiling .... . .... ... .... ... ... . . .
Total weight ....... . .................. .
Military load .......................... .
Unsup ercharged
43 minutes
90 m. p. h.
20.250 feet
2820 lbs.
912 lbs.
S it/Jerchargcd
333,;; minutes
136.5 m. p. h.
33,000 feet (estimated)
2990 lbs.
912 lbs.
Pending the development of a side-type supercharger which permits easier streamlining with
resultant lessened parasite resistance, no further work on Form "C" supercl:arger will be under­taken.
Several photographs showing ck>se-up views of the installations in the DH-4BW and
Orenco "D" airplanes are appended.
20
Research and Experiment-Serial Reports
Cooling Test of Huff-Daland TA-2 Training Airplane with Curtiss
"OX-5" Engine. Serial No. 2028
The object of this test was to determine the efficiency of the cooling system installed on a modi­fied
Huc-Daland training type airplane equipped with a water-cooled engine. It was found that the
cooling performance of the airplane was satisfactory since it could be flown during full climb on a
temperature difference of 54° C. and during level flight on a temperature difference of 47° C. Full
climb can therefore usually be made without boiling at a ground temperature of 38° C ( 100° F.)
and "full throttle" level flight at an air temperature of 41 °C ( 107° F). The construction of the
radiator and shutters was not satisfactory as it had not been made entirely in accordance with the
Engineering Division's specifications.
Views, description, and performance data on this airplane were published in Technical Bul­letin
No. 28.
I< ailure of Supercharger Rotor Buckets. Serial No. 2030
During the early experiments with the Form "A" supercharger, one of the rotor buckets was
ocassionally broken off. These failures caused little trouble and the turbine wheels were kept jn
service until several buckets had failed.
\~Then the Form "D" superchargers were testec!, leaner mixtures were used with the result
that the rotor buckets stretched and failed in numbers. Some buckets were elongated to the ex­tent
of 3/ 16 inches and showed signs of "necking." Failure of the Form "A" buckets was due
to flaws in the material whereas the failure of the Form "D" supercharger buckets was clue al­most
entireiy to stretching, some of the buckets actually pulling apart at their weakest cross-sec­tion.
The average life of the Form "D" turbine wheels was seven hours and thirty minutes each.
After a careful analysis of all the factors entering into the failnre of these buckets, it was
apparent that it would be necessary either to lower the temperature of the exhaust gas, to de­crease
the rotational speed of the turbine, or to decrease the weight of the inoperative material of
the buckets. Since the lowering of the exhaust gas temperature would reduce the available power
in the gas and require some method of cooli!1g and the decrease in the rotational speed would
lower the compression ratio of the compressor, it remained therefore, to reduced the dead weight
of the bucket.
The last alternative gave very c;atisfactory results. This was accomplished by completely re­moving
the shrouds of the buckets, thus leaving the ends exposed. From actual flight tests, it was
found that the tnrbine wheel with the shrouds removed gave as much service as the regular wheel
and also gave indications of longer Ii fe. This method is recommended for modifying the present
Form "D" superchargers.
\'iews of the rotors ,..vith and without shrouds are given.
Comparison of High and Low Compression Liberty Engines with General
Electric Form "D" Supercharger. Serial No. 2033
It was proposed to compare the performances of two DH-4B airplanes, one equipped with
a high compression Liberty engine and Form "D" supercharger and the other with a low com­pression
Liberty engine and similar supercharger. Both engines were supercharged to sea level.
Due to the greater power of the engine with high compression, the airplane using this engine
would naturallv have the better performance.
A..ccorcling to calcnlations made by the Engineering Division and the General E lectric Companv,
the power of the low compression engine could be made 7 per cent greater than that of the high
compression engine, with an increase in fuel consumption of only 12 per cent. The actual test to
prove this assertion was not carried out owing to an accident to the low compression engine. The
appended curves in the report are therefore of interest merely as a comparison between these e11-
gines under similar conditions.
21
Research and E xperiment-Materials
INVESTIGATION OF MATERIALS
GENERAL.
Straight Side Wheel 54x12.
The largest of straight-side airplane tires and wheels on the present program is a 54x 12
straight- side wheel and tire originally designed to carry a normal working load of 10,000 lbs. at
70 lb. air pressure. The weight of the complete assembly of tire and wheel was estimated at 175
lb. The load carrying requirements were sati sfactorily complied with. and the weight of the as­sembly
was 165 lb. Service tests on the new type a re being run on the Martin Bomber ai rplane.
Coating for Duralumin.
The tests made upon different primers to be used as protective coatings for duralumin. 111-
clicate that linseed oil primer, containing iron oxide will give the best protection to this metal.
Heat-Resisting Enamel for Air-Cooled Engines.
\Vhile investigating the problem of coating air-cooled engines, it was found that an enamel
made of lin seed and castor oils gave very satisfactory results in the laboratory. T his enamel with­stood
a heat of 800° F . for fifteen minutes, while the commercial enamel tested for this purpose
failed between 600° and 700° F . T he results a lso indicate that a suitable enamel will reduce the
heat of the aluminum used in air-cooled engines.
METALS.
Metallography of Ingot Aluminum.
During the past several years, great strides have been made in the study of the microscopic
structure of aluminum and its alloys, but the nature of the occurrence of the two elements, iron
and silicon, which are always present as impurities in Commercial Ingot, has been very baffling,
owing to the simila rity between the different constituents formed. It was to clear up this mystery
and to form a basis for all future metallographic study that this in vestigation was undertaken. It
has been possible to definitely identify the two constituents, FeA13 and the constituent "X," a
constituent clue to both iron and silicon, and to show their natural habits of crystalli zation. Free
silicon was readily recogni zed as a result of p revious investigations. The accompa nying micrograph,
IRON CONSTITUENTS IN AN ALLOY OF ALUMINUM.
Etched with HNOa (Quench) . Magnification to I 000 diameters.
22
Research and Experiment-Materials
shown below, illustrates the possibilities of ·photographing these constituents at a magnification of
1000 diameters. The etching reagent used has definitely revealed three different constituents : the
dark core is FeAl , and the outer constituent which is etched is the constituent "X"; the half tone
constituent is metastable and would revert to the constituent "X" on prolonged annealing. This is
taken from an alloy of silicon, 4.60% ; iron, 8.88% ; balance, aluminum.
New Steel Specifications.
The l\faterial Section has recently prepared and issued new steel specifications. The num·
bers of these specifications conform with the former issues. The principal cnange has been the
elimination ,of reference to more than one analysis in the specification. The scheme of the present
specifications was to pick the analysis in the old specification which was most generally used, and
which would give the physical properties called for in the old specification, and use this analysis
solely as the basis of the revision. All reference to physical properties has been deleted from the
specifications, and new specifications have been drawn up, which have been given HT numbers,
and which cover the heat treatment of the steels. Each heat treatment specification contains a
physical chart which shows in general, the physical properties which can be obtained from the steels
covered by the analysis in the purchase specification.
A color scheme for marking the steels according to the specification number has also been in­cluded
in the new specifications, and this scheme should he followed by all Supply DejJots, so that
the procedure in this respect will L,e uniiorm throughout the Air Service.
Specification J\i o.
10,028-B
10,029 A
10,030-C
10,035-B
10,036 C
10,037-C
10,045-C
10.046-C
10,047-D
10.048-C
10,049-C
10,050-C
STANDARD STEELS.
Steel No.
1020
2330
1020
1035
1035
1045
2330
6135
3140
3240
6150
3250
Analysis
Carbon, .15-.25; Manganese, .30-.60; Phosphorus
(max.), .045 ; Sulphur (max.) , .050.
Carbon, .25-.30; Manganese, .50-.80; Phos­phorus
(max.), .040; Sulphur, (max.), .045;
Nickel, 3.25-.3.75.
Carbon, .15-.25; Manganese, .30-.60 ; Phos­phorus
( max.) , 045; Sulphur (max.), .050.
Carbon, .30-.40; Manganese, .50-.80; Phosphorus,
(max.) , .045 ; Sulphur (max. ), .050.
Carbon, .30-.40; Manganese, .50-.80; Phosphorus,
(max.), .045; Sulphur (max.) , .050.
Carbon, .40-.50; Manganese, .50-.. 80; Phosphorus
(max.) , .045; Sulphur ( max.) , .050.
Carbon, .25-.35; Manganese, .50-.80; P hosphorus
(mn.), .040; Sulphur, (max.), .045; Nickel,
3.25-3.75.
Carbon., .30-.40; Manganese, .50-.80; Phosphorus
(max.), .040; Sulphur (man.), .040; Chro­mium,
.80-1.10; Vanadium (min.), .15.
Carbon, .35-.45; Manganese, .50-.80; Phosphorus
(max.), .040; Sulphur (max.), .045 ;:.Jickel ,
1.00-1.50 ; Chromium .45-.47.
Carbon, .35-.45; Manganese, .30-.60; P hosphorus
(max.), .040; Sulphur ( max.) , .040; NickeL
1.50-.2.00; Chromium, .90-1.25.
Carbon, .45-.55; Manganese, .50-.80; Phosphorus
( max.) , .040; Sulphur (max.), .040; Chromi­um,
.80-1.10 Vanadium (min.), .15.
Carbon, .45-.55; Manganese .. 30-.60; Phosphorus
(max.), .040; Sulphur (max.) .. 040; Nickel,
1.50-2.00; Chromium, .90- 1.25.
23
Research and Experiment-Materials
10,051-B 3415
10,052-B 2320
10,055-A Tungsten
10,056-A 1095
10,058 6120
10,059 3130
10,060 3435
10,061-A 51235
10,062 6195
Casting Magnesium-Zinc Alloys.
Carbon, .10-.20; Manganese, .45-.75; Phosphorus
(max.), .040; Sulphur (max.), .040; Nickel,
2.75-3.25; Chromium, .60-.95.
Carbon, .15-.25; Manganese, .50-.80; Phosphorus
(max.), .040; Sulphur (max.), .045; Nickel,
3.25-3.75.
Carbon, .60-.70; Tungsten 5.00-6.00; Man­ganese,
.30-.45; Phosphorus (max.) , .030; Sul­phur
(max.), .030.
Carbon, .90-1.05; Manganese, .25-.50; Phosphor­us
(max.), .040; Sulphur (max.), .045.
Carbon, .15-.25; Manganese, .50-.80; Phosphorus
(max.), .040; Sulphur (max.) .040 ; Chrom­ium,
.80-1.10; Vanadium (min.), .15.
Carbon, .25-.35; Manganese, .50-.80; Phosphorus
(max.), .040; Sulphur (max.), .045; Nickel,
1.00-1.50; Chromium, .45-.75.
Carbon, .30-.40; Manganese, .45-.75; Phosphorus
(max.), .040; Sulphur (max.), .040; Nickel ,
2.75-3.25; Chromium, .60-.95.
Carbon .30-.40; Manganese, .20-.50; Phosphorus
(max.), .035; Sulphur (max.) , .035; Nickel,
.SO; Chromium, 11.5-14.0.
Carbon, .90sl.05 ; Manganee, .20-.45; Phosphorus
(max.) , .03; Sulphur (max.), .03; Chromium,
.80-1.10; Vanadium (min .) , .1 5.
The investigation of the methods of casting magnesium-zinc alloys has recently revealed the
advisability of melting these alloys in an atmosphere of nitrogen or in a vacuum. The results ob­tained
hy this method of melting, together with the use of special molding sand preparations and
proper drying of the molds, show that sound castings can be produced in various shapes and that
many of the obstacles heretofore confronted are thereby eliminated.
Porosity just beneath the skin of the casting has been the principal defect encountered, but the
causes of these pores are rapidly being eliminated, and it is belieYed that in the near future, castings
of any description may be made from these alloys.
The outstanding advantages of the magnesium alloys over aluminum alloys are:
a. Good machinabilitv.
b. 40 per cent sa\'ing in weight.
c. A bout 300 per cent increase in elongation with the same tensile strength.
Investigation of Magnesium Alloys "Elektron Metal."
The problem of casting magnesium alloys into useful shape<; has offered many difficulties not
encountered with other metals. During the past year, the Materi2.l Section has been investig-afr1g
the behavior of a metal composed of 95 per cent magnesinm and 5 per cent zinc. This alloy is
produced in Germany under the name of "Elektron Metal." Due to the extreme chemical affini­ties
of this alloy, many precautions have been found necessary in order to prevent burning and
porosity. Special sand preparations, long and thorough drying of the molds, the use of an inert
atmosphere over the metal while melting, and special methods of gating the castings have been
found essential to good results. By use of a specially designed pot, melting in any desired atmos­phere
has been made possible. Hydrogen gas and carbon dioxide gas have proved deterimental, due
to absorption in the metal, while nitrogen gives the necessary protection against burning without
detrimental effects. Melting in a partial vacuum has proven sucessful, but cumbersome for pro­duction
practice.
24
APPARATUS FOR CASTING "ELEKTRON" METAL
1. Permanent Piston Mold and Core. 3. Sealed Iron Pot. 5. Calcium Chloride. 7. Nitrogen Tank.
2 . Dried Sand Cores. 4. Pyrometer. 6 Melting Furnace. 8. (Insert) Castings.
Research and Experiment-Materials
The principal advantages of this alloy over aluminum alloys are its low specific gravity ( 60
per cent of aluminum), high elongation (8 per cent in 2 inches) and good tensile strength ( over
20,000 lb. per sq.'in. as cast.)
Corrosion of Light Alloys.
An investigation of a method of the inhibition of corrosion of light alloys is under way. Final
conclusions cannot be made at this time, clue to the lack of evidence, but preliminary results show
that this treatment when applied to aluminum alloys, will withstand the salt spray corrosion test
continuously for four clays without any visible attack, whereas, the untreated specimen showed
signs of corrosion by similar exposure within two hours.
Macro and Micro-Structure of Connecting Rods for W-lA Engine.
An investigation was made to determine the macro and micro-structural differences ex1st111g
in two Model vV-lA master connecting rods as forged by dissimilar methods. The conclusions are
as follows:
The Packard rod, forged in a single heating, on coarse etching, de,;elopecl forging flow lines
most prominently transversely and radially to the major axis; whereas the Davis rod, forged in
three heatings, developed them most strongly longitudinally. The large encl of both forgings con­tained
deep laps, probably due to insufficient metal in the blank after the roughing operation. The
material specified for- the rods was 3140 steel, but the Packard stock, unlike the Davis, did not
conform to the requirements.
Effect of Drawing Temperature on the Strength and Ductility of 6120 Sheet Steel.
The Air Service has standardized on the use of one graJe of allov sheet steel for fittings. This
standard was made after se,.1eral test~ had been conducted on steels of different analyses and it was
found that the steel selected gave the best bend tests and could therefore be fabricated into fittings
with greater ease than steels containing nickel and chrome-nickel. The steel selected has the follow­ing
chemic.,al composition:
Carbon ........................... .
Manganese ........................ .
Phosphorus (max.) ... . .. .. ........ .
Sulphur ..... . ..................... .
-Chromium . . . . . . .............. . ... .
Vanadium (min.) . .. .. .. ...... '. .... .
.15- .25
. SO- .80
.04
.04
.80-1.10
.15
vVhen a steel is standardized it is advisable to get complete curves representing the variation
of physical properties with different heat treatments and for different gage thicknesses. The tests
made in the past six months coyer gage thicknesses .022 to .25. Specimens were quenched in oil
at 1650° F. and drawn at 1300, 1100, 825, 625, 400, and 200° F ., and some were tested with no
draw. A similar set of heat treatments was made using water as a quenching medium instead of
oil.
Figures No. 1, No. 2 and No. 3 on pages 28, 29 and 30 show the effect of the drawing tem­peratures
upon the proportional limit, ultimate strength, and percentage of elongation in two
inches. These results are for water-quenched specimens taken with the direction of rolling. Similar
results were found for oil-quenched specimens, with the exception that the proportional limits and
ultimate st~engths were lower, while the elongations were slightly higher.
From the proportional limit graph it is evident that the proportional limit does not increase
continuouslv with decrease in drawing temperature, but reaches a critical temperature somewhere
between 600 and 800 F., after which its decreases. It is also noticeable that the very thin sheet,
.022 gage, gives very low values. Furthermore. the gage .25 gives lower values than any of the
four remaining sheets, which in turn show a general increase in proportional limith with increase
in thickness.
26
Research and Experiment-Materials
From the ultimate strength graph it is evident that there is a general increase in strength with
decrease in drawing temperature. The .022 gage material , however, gives very low values and
shows a decrease in strength at the "no draw" point. The .25 sheet gives rather low strength
values.
The elongation graph shows a decreas~ in elongation with decrease in drawing- temperature.
It is very clear here that the elongations vary with the gage thickness, being higher for the thicker
sheets.
TEXTILES.
Machined-Sewed Seams for Wing Covering.
The investigaion on machine-sewed seams has been completed and the preliminary report is be­ing
written. This investigation was made to determine the relative suitability of cotton, linen , and
silk sewing threads for airplane wing covers; also the effect on these threads of ammonium phos­phate
when used as a fire-proofing agent.
WOOD.
Moisture Content of Fokker Wing Beams.
It was found that the moisture content of the wood in the wing beams of the Fokker planes
was between 15 and 16 per rent. This is excessively high for most localities in this country.
The result will be a gradual lowering of the moisture content accompanied by a shrinkage in the
material and a loosening of joints and hrace wires. This has already occurred in one plane at
this field.
Isolated Factors in Kiln Drying.
This work is being done at the Forest Products Laboratory in cooperation with the Navy De­partment
and the Forest Service. The first test run on birch has been practically completed. This
investigation gives great promise of producing results of great benefit to kiln-drying operations.
Effect of Discoloration in Walnut Airplane Lumber.
This project was brought to the attention of this Division through a great deal of discolored
walnut at the plant of the Curtiss Aeroplane and l\Iotors Corporation. Tests at the Forest Pro­ducts
Laboratory and at this Division showed the material in its kiln-dried state to he about 1 S
per cent under ·normal in toughness. It was concluded that the discoloration and lower tough­ness
values were clue to improper kiln-drying.
Effect of Stains, Molds, and Decay on Airplane Woods.
This work is being conducted at the Forest Products Laboratorv in cooperation with the Navv
Department. To elate it has been determined that the yellow strai~ and subsequent deterioration i~
oak is caused by a fungus which propagates and spreads from one board to another in a pile.
:2 j
Research and Experiment-Materials
2'44000
-zzaooo L,
i., .... ,,
I, '"
I "'
,.,
,_ .
ZtJ0,000 .,
1.- ,,
L,
I.I ,,
,,
/o'0,000 , V ,,, ., ,.,
j
. I
"' I.I ,, V" "" I,
164000
,., ,., ,, ,...
"' i,
II ,.,
i., ....
/t!0,000
I ,,
I ,,
I ,~
I ....
! ~ "' "' '--"- -1. ,,
/24~ i, ~
V I
I ,, ,, I
1ar:_ L,
~~
I
J,
I ..
'
60,tW
I
1,l)ttJ t+ ii"~ /tJiJO dtJO --- oOtJ 400 zoo
OR/IW//Y6 Tel"!/;' Dc6.r.
FIG. I-PROPORTIONAL LIMIT.
28
Researc~ and Experiment-Materials
I !
-
'
' r
'
! . '
'
'
140,Q],, - -
~ , .
,, . '"" JI :;, ""'
IZO,Ot ·
,., .,
"
'' ...
I
/tJaw ....
., , ' '- \. , .....
' ' ...
, ~ ~
o'tJ.0(), " ,
]
' "'
"" !,I
I "'. I 6aooo
I ... ""' I
4Q0(),' ...
' ~ ..
,~
'fJ.OiJO ..... llOO lddO d()() -~ qoo ZI. '(j
ORrlW!/YG Tc/'1P. OeG. r. ""'
FIG. 2-ULTIMATE STRENGTH.
29
Research and Experiment-Mater ials .
...
\
/4 I\
" ....
1-.... t \
II. " ... 7
u 1c .... ,..,
II. ~ ...
' .... t -· 1-1- I- - q:: ' " ' "'
10 • C- -- .
~ ... R "
" ·+ ~ baa 0 L ~--
tJ ~ ... ,_ - ~ ·. ~~·
~ - . '.I - 1-1- ... ,. .. I 1-C.. - ~ _L
_._
f, I', __ J_,L_ · rs i
"
_._,_
,.. t. ,.... I
-i:-- , _
I -· ',:::
<., \ I' " " " . ,_ ,_ 1-j-
.J.
.... I, 1-'-· . 1-1- .
,.... Iii'
c:. "" I, " - .
·-
I-C
, 'ZOO /i llv d()() oOO - ,_ I(~ } i_ ~·r,
OR/IW!/YG Tc/'!P. DcG. r. NO DIPAW'
F IG. 3.-ELONGATION.
30
FOREIGN DEVELOPMENT
FRANCE
AIRPLANES.
Metal Construction.
Metal construction is the keynote of the present aeronautical development in France with the
result that practically all of the experimentation is being. concentrated in the development of the all­metal
types. The requirements laid down by the French Air Ministry that all military airplanes
shall be capable of being stored indefinitely under various weather conditions without great re­sultant
deterioration, have been largely instrumental in the production of the all-metal airplane.
How far this influence is manifested in the construction of recent types may be readily seen
in the production program of the principal aircraft manufacturers. The Berguet, Morane-Saul­nier,
Potez, and \ i\Tibanlt companies are producing almost exclusively all-metal airplanes or air­planes
of metallic construction with fabric covering. The same is true of the large Schneider fac­tories.
The Farman ::md Hanriot Companies are using wood and metal construction with an
advanced tendency toward the latter. The only important companies adhering to the wood con­s1ruction
are the Nieuport and S. P. A. D. aircraft establishments which are perhaps retaining
this method on account of its adaptability to monocoque construction.
Abandonment of Twin-Engined Type.
Another important innovation adopted by the French is the absolute abandonment of the twin­engined
airplane for heavy bombardment purposes. In order to insure more dependable opera­tion,
the multi-engined airplane must be powered by three or more engines with independent in ­stallations
and accessories so that the failure of one engine or any of its accessories will not affect
the functioning of the other engines. This type of airplane must be able also to operate in normal
flight with only one-half or two-thirds of its aggregate horsepower.
The latest contribution in the exemplification of this development is the Henri-Paul Schneider
Bn3 night bomber described in the following article.
Henri-Paul Schneider Bn3 •
The Etablissements Schneider et Cie ( Schneider and Company) of Havre have recently com­pleted
and delivered to the French Air Ministry a large cannon-carrying airplane designed for
night bombardment. This airplane is a three-seater, all-metal biplane equipped with four Lorraine­Dietrich
engines and a 75 mm. cannon. It is claimed to he the first airplane of this kind to be used
for artillery material by the French government. The French designation for this airplane is Army
Type Bn, , a three-place night bomber.
The original design is accredited to a French engineer by the name of Drosne. The phns
and development work were done by the Technical Service for Aeronautics ( S. T. Ae.) which is
under direct supervision of the French Air :Ministry. The actual construction was carried on
by the Schneider Company at their factory in Chalon-sur Saone where static tests of the fuselage
and other parts were conducted in 1921 and the first airplane completed in October, 1922.
31
Foreign Development-France
This airplane was then sent to the company's plant at Havre, where the 75 mm. cannon and
mount of special design were installed. Both the gun and the mount were designed by Tournier,
a former artillery officer and a lso chief designer of the Schneider Company for 15 years. After
a brief test lasting only a few minutes, the airplane was flown successfully from Havre to Villa­coublay,
the government experimental station , by the well-known pilot, J ean Casale. Only two
forced landings were made en route on this ZOO-kilometer ( 12.S miles) cross-country flight. These
were due to minor engine troubl es. In view of the fact that this was only the second flight for
such a large airplane, this feat is considered by the French as being a fine example of good piloting.
SCHNEIDER Bn -BOMBARDMENT.
3
(Four Lorraine-Dietrich 370 h. p . Engines) .
32
Foreign Development-France.
The size and weight of the Schneider night bomber are quite impressive as may be observed
from a careful study of the general characteristics and the accompanying photographs. The struc­tural
features insofar as details are available are no less interesting.
Wings.- The upper and lower wing panels are symmetrical having the same chord and span
with considerable sweep back at the outboard sections. The lower wing has a dihedral of 1 ° 45'
above the horizontal.
The internal structure is entirely of metal. It consists of two rectangular spars formed of
two "U" sections or channels of chrome-nickel steel united by short vertical and diagonal web
pieces. Alloy-steel webs of great strength .and lightness are riveted to the spars. Both the spar sec­tions
and the webs are steel stampings. The internal bracing is provided by metal compression
tubes braced by piano wires with turnbuckle adjustment.
Fabric covering is used on the wings excepting certain portions covered with sheet metal in
the Yicinity of the ailerons. There are four ailerons of the unbalanced type.
The interplane and cabane struts are steel tubes with streamline fairing. Ball and socket joints
are provided for fastening the struts to the lower wing spars and pin joints at their junction with
the upper wing spars.
Empennage.-The tail group is of the biplane type with a span of 24' 11 .Ys" and is attached to
the upper fuselage longerons. Each horizontal panel or stabilizer carries an elentor.
Three rudders are mounted between the horizontal stabilizers, the outside rudders being used
for control and the central rudder for directional stability in case of engine failure in which event
it may be set by a handwheel in the pilot's cockpit.
Metal construction with fabric covering is used thruout the tail surfaces.
Fuselage.-Four steel tubular longerons about four inches in diameter form a rectangular
framework upon which the fuselage is built up as a box-truss without any interior bracing ·what­ever
from the mechanic's cockpit to the rear. From this cockpit forward. the fuselage is covered
with sheet metal cowling. Fabric is used on the tail section. The maximum width of the fuse­lage
is 6' lOU" and the maximum depth 7' 10§1". The structure is assembled by means of steel
plates and all bracing is furnished by piano wires.
A wheel-type dual control is placed in the pilot's cockpit.
Landing Gear.- A two-wheeled chasis is mounted under each group of engines, making a
very wide tread of 19' 8,Ys". The wheels are 1250 mm. x 250 mm. in size . . The shock absorber is
a patented device, 'the details of which are not yet available.
A single-wheeled auxiliary landing gear is suspended beneath the nose of the fuselage to pre­vent
damage in landing.
Power Plant.-Four twelve-cylinder, water-cooled Lorraine-Dietrich engines, each operating
independently. are arranged in two groups, each of which consists of one . tractor and one pusher
housed in a cylindrically shaped nacelle monnted between the wings. The engines operating as
tractors drive two-bladed propellers, whereas the pushers drive four-bladed propellers. Each en­gine
develops 370 horsepower.
The fuel is carried in six cylindrical tanks installed in an upright pos1t10n inside the fuselage
behind the mechanic's cockpit. \iVind-driven pumps, one for each tank, supply fuel to the car­buretors.
Hand-pumps are used for starting.
The oil is contained in four separate reservoirs, one for each engine, from which it is pumped
by an engine-driven pump.
·water cooling is effected by the use of ordinary honeycomb radiators mounted directly over
each nacelle. Shutters are provided for regulating the temperature,
33
Foreign Development-France.
Equipment.-The airplane is provided with bomb racks and other necessary night bombing
equipment.
The principal feature of the armament is the 75 mm. semi-automatic cannon which is de­signed
for use against objects on the ground. This gun is mounted in the center of the fuselage
on a pivot mounting of special design by which the fire may be directed downward thru an arc
of 130 degrees in a vertical plane, thus leaving an arc of 25 degrees below the horizontal in both
the front and rear positions thru which the gun cannot be fired. The gun cannot be traversed in
azimuth during action but must be set by hand before firing. The weight of the cannon is about
1100 pounds and requires two men to operate it.
No further details of constrnction or performance data are available at this writing. The air­plane
is now undergoing a series of tests at Villaccublay, Seine et Oise, under direction of the en­gineers
of the French Air Ministry.
GENERAL CHARACTER IS TICS.
DIMENSIONS_.
Span . ... ... .. .... .. .... .. . ........ .. ................ . .. .
Length . .... ..................... ... . . ..... ..... ........ ,
Height . . . .. ... ... .. .... .... . ... . .. .. . . . ... . . .. ...... ... .
Chord ( both wings) ...... ... .................... .. ..... .. .
Gap ... .. ..... ... ..... . ..... . . .... ..... .. .......... ..... .
AREAS.
Ailerons (unbalanced) .. ..... .. ... .. . ..... ... ..... . . .. ... . .
E levators . . .. . .. .. .. . . ..... ... .. ....... ... .... . . .... . . . . .
Fin ...... ... ....... . ..... .. . . .. . ... .. ........ . . . . ... .. . .
Rudders . ... ... .. .... ... . .......... .. . .. .... .. - ....... .. .
Stabilizers (horizontal) . , ..................... ... ......... .
Total area including ailerons ..... . . . ...... . .... ............ .
WEIGHT.
98' 4U"
65' 3"
20' 0"
12' 150"
12' 150"
215.28 sq. ft.
96.87 sq. ft.
21.54 sq. ft.
107.64 sq. ft.
139.93 sq. ft.
2,367.2 sq. ft.
Total weight fully loaded . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26,790 lb.
THEORETICAL PERFORMANCE,
Speed at 6.560 ft .. .... ............. . .. . .... .. ... .... ...... .
Minimum speed at ground . . ... ... .. ... . ...... . . . .. ........ .
Absolute ceiling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... .. .. . .
Endurance .. . .. . . .. .. . ....... . ...... . ... ....... ......... .
34
93 m. p. h.
50m. p. h.
16,400 ft.
5 hours
. France.
NEW BOOKS AND DOCUMENTS
REFERENCE DATA ON AERONAUTICAL DEVELOPMENT
AND ENGINEERING IN THE l.'NITED STATES AND
OTHER COUNTRIES ADDED TO THE TECHNICAL FILES
OF THE E:r-J"GINEERING DIVISION, AIR SERVICE.
AVIATION AND AEROSTATION .
Lessons of the recent gliding flights in the Rhoen Mountains, tr. from
Illustrierte Flug-Woche. Sept. 13, 1922. M. I. D. 2028-386. Oct. 16.
1922. 5 p.
United States.
Battles and campaigns of the United States. Battle credits for combat
service or service in the theater of operations for the 28th, 33d, 42d, divisions
and miscellaneous units, \i\Tar Dept. General Orders No. 41. Oct. 9, i922.
1() p.
Award of medal of honor, distinguished-service medal and citations ro:­gallantry
in action. \i\Tar Dept. General orders No. 43. Oct. 23, 1922. 14 p.
Instructions concerning surplus Air Service property. \Var Dept. 0. C.
A. S. Circular No. 103. Nov. 28, 1922. 1 p.
Procedure for Engineering Division services and supplies furnished to
other than Engineering Division activities. War Dept. Engineering Division.
Administrative circular No. 28-A. Nov. 9, 1922. 2 p.
Records.
New ruling regarding trials for airplane speed records.
Aeronautique 'Internationale. M. I. D. 2086-315. Italy 6685.
Oct. 14, 1922. 1 p.
Federation
ON 12391.
Record of performances of British airplanes, ship airplanes, and sea­planes.
Air Ministry. Dec., 1921. 2 p.
Notes on French aviation covering try for altitude record· by Adj. ;',fou­tonnier;
Lamblin coupe won by Lt. Rabatel for best flying time over triangular
course. M. I. D. 2081-374. France 6256-W. Oct. 30, i 9?2. 1 p.
Notes on French aviation covering altitude record of Nienport 29Cl; tests
of floats on dirgible me,iiterrance; pi lot school at Istres; Pescara helicopter
and prize offered by Ni,euport Astra Company.for successful parachute. M.
I. D. 2081-369. France 6221-W. Oct. 23, 1922. 2 p.
35
D52.19/ 1
D00.12/ 32
1922-No. 41
D00.12/ 32
1922-No. 43
D00.12/ 98
1922-103
D00.1209
1922-28-A
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New Books and Documents.
RESEARCH AND AERODYNAMICS.
Aerodynamic properties of thick aerofoils, II; by F. H. Norton and D. L.
Bacon. National Advisory Committee for Aeronautics. Report No. 152.
1922. l S p. Charts.
Some effects of baffle flaps on aerofoil characteristics; by R. M. Bear.
Navy Yard. Construction Department. Report No. 201. Sept. 9, 1922. 33
p. Charts.
Air force and moment for Albatross wings A and B. Navy Yard,
Construction Dept. Report No. 204. Oct. 3, 1922. 10 p. Charts.
Air force and moment for a modified U . S. A. 27 aerofoil. Navy Yard.
Construction Dept. Report No. 203. Sept. 30, 1922. 6 p. Charts.
Air force and moment for Bureau spotting seaplanes. Navy Yard.
Construction Department. Report No. 198. Sept. 19, 1922. 13 p. Photo­graph,
drawings, charts.
Air Force and moment for MB7 Wling. Navy Yard. Construction .De­partment
Report No. 202. Oct. 6, 1922. 5 p. Photographs, charts, diags.
Preliminary study of airplane performance; by F. H . Norton and \V.
G. Brown. National Advisory Committee for Aeronautics. Technical Notes
No. 120. Nov., 1922. 7 p. Photographs, charts, drawings.
Lateral control of Bristol Fighter at low speeds. Measurement of roll­ing
and yawning moments of model wings due to rolling; by F . B. Bradfield.
Aeronautical Research Committee Reports and Memoranda No. 787. (Ae.44)
T. 1673. Jan., 1921. 23 p. Illus., charts.
Elimination of dead center in the controls of airplanes with thick sec­tions;
by Thomas Carroll. National Advisory Committee for Aeronautics.
Technical Notes No. 119. Nov, 1922.
Aerodynamic pressure on an airship hull in curvilinear flight; hy R.
Jones. Aeronautical Research Committee. Reports and Memoranda No.
780. (Ae.40) (T. 1651). Nov., 1921. 11 p. Charts.
Experiments on a model of rigid airship R. 23, together with a compari­son
with the results of full scale turning trials and a consideration of the
stability of the ship ; by R. Jones and others. Aeronautical Research Com­mittee.
Reports and Memoranda No. 779. (Ae.39). (T. 1623). Sept.,
1921. 22 p. Charts, diags.
Motion of airships under certain imposed movements of the rudders ;
by R. Jones, Aeronautical Research Committee. Reports and Memoranda
No. 781. (Ae.41) (T. 1658). Nov., 1921. 27 p. Charts.
Stability and resi stance experiments on a model of Vickers rigid air­ship
R. 80 ; by J. R. Pannell and others. Advisory Committee for Aeronau­tics.
Reports and Memoranda No. 541. T. 1212. Aug., 1918. 12 p. Charts,
diags.
Internal stress in laminated construction; by A. L. Heim and others. Na­tional
Advisory Committee for Aeronautics. Report No. 145. 1922. 56 p.
Ills. Charts.
On the determination of the stresses in braced frameworks. Part 2. The
The effert of shear upon a framework of uniform rectangular cross-section;
by R. V. Southwell. Aeronautical Research Committee. Reports and
Memoranda No. 790. (Ae. 47) T. 1685. Feb., 1922. 15 p. Diags.
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Spotting
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R. & M.
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R.&M.
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R. & M.
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R. & 1\1.
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R. & M.
New Books and Documents
On the determination of the stresses in braced · framework Part 3. The
effect of axial loading, torsion , flexure and shear upon a braced tube of any
uniform cross section; bv R. V. Southwell. Aeronautical Research Com­mittee.
Reports and Men1oranda No. 791. (Ae. 48) T. 1706. Apr., 1922.
16 p. Diags.
AIR SERVICE ENGINEERING SCHOOL.
Courses of Instruction.
Course in general aeronautical enginering. Contracts. Air Service
Engineering School. McCook Field. Nov., 1922. 17 p.
E lements of patent law; by H . E. Stauffer and Maj. R. H. Young. Air
Service Engineering School. McCook Field, July 17, 1922.
Chemi stry of aircraft materials. Air- Service Engineering School. Mc­Cook
Field. Nov. 1, 1922. 94 p.
Laboratory course for fabrics; by C. J. Cleary. Air Service Engineering
School. McCook Field. 1922. v. p.
Contents :
!. Introduction to textiles with definitions.
2. Identification.
3. General tentative methods for testing materials.
4. Physical testing of textile materials.
5. Application of airfoil coverings.
Strength of materials; by C. P. McLaughlin and Alfred Niles. Air
Service Engineering School. McCook Field. 1922-23.
Contents:
1. General theory.
3. Application to airplane design.
E lementary engine design Course in engine and plane maintenance, II ;
by G. D. Angle, Air Service Engineering School. McCook Field, 1922. v.
p. Charts.
Brief notes on pyrometry heat treatment and brazing; prepared by H.
V. Schaal. Air Service E ngineering School. Oct., 1922. Large document,
photographs.
Testing of ·woods and wood parts used in aircraft construction; by R.
L. Hankinson. Air Service Engineering School. McCook Field, 1922. 16 p.
AERIAL NAVIGATION.
Aerial Travel Orders.
Instructions concerning payment of actual and necessary expenses to
officers and per diem warrant officers :mc! enlisted men while traveling- by air
on duty without troops under competent orders. \Var Dept. 0. C. A. S.
Circular No. 102. Nov. 28, 1922. 3 p.
General.
AIRCRAFT.
(Heavier-than-air.)
Brief description of cannon carrying airplane built for French Air Minis­try;
by H. D. Finley. France 73731. Oct. 18, 1922. 1 p.
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Misc.-French
New Books and Documents
Inspection of struts and members of aircraft. War Dept. 0 . C. A. S.
Letter of instruction No. 69. Nov. 10, 1922. 1 p.
Seaplanes. Taking off and alighting; by E. S. Goodwin. Aeronautical
Research Committee. Research and Memoranda No. 78. (Ae. 37). (T.
1669) . Dec., 1921. 10 p.
Types of airplanes and seaplanes in France and total number in use
Sept. 30, 1922. M. I. D. 2081 -371 / 2. France 6178-W. Oct. 16), 1922. 1 p.
DeHaviland.
Instructions concerning oil tank capacity of DeHaviland 4Bl and 4B2
Airplanes. War Dept. 0. C. A. S. Letter of in struction No. 68. Nov. 10,
1922. 1 p.
Instructions concerning use of DeHaviland 4 B photograph airplanes.
War Dept. 0 . C. A. S. Circular No. 96. Nov. 13, 1922. 1 p.
Farman.
Characteristics of Farman Despatch, equipped with Anzani 6-cylinder en­gine.
n. cl._ 1 p. Photographs, blue prints.
F-5-L.
Performance characteristics of the F-5-L seaplane; by W. S. Diehl.
National Advisory Committee for Aeronautics. Technical Notes No. 118.
Oct, 1922. 8 p. Charts.
Junker.
Static test and characteristics of Junker all-metal limousine monoplane.
(in Etat trimestriel des etudes. July, 1922. p. 14.) Translated July, 1922.
LePere.
Performance of LePere airplane equipped with Liberty 12 engine and
general Electric supercharger. Flight Test Branch. McCook Field. n. cl.
1 p. Charts.
Martin.
Maintenance difficulties on the Martin bomber MB2 and NBSl. War
Dept. 0. C. A. S. Letter of instruction. Oct. 23, 1922. 2p. Blueprints.
New kater drain cocks for Martin bomber MB-2 and NBS-1 airplanes.
War Dept. 0 . C. A. S. Letter of instruction No. 71. Nov. 14, 1922. 1 p.
Blueprints.
Landing wheel streamlines for Martin bomber MB2 and NBS-1 air­planes.
\Var Dept. 0. C. A. S. Letter of instruction No. 70. Nov. 14, 1922.
1 p.
S.P.A.D.
Description of the Bleriot Spad 40 A2, equipped with a 370 H. P. Lor­raine
engine. M. I. D. 2081-346/ 3. France 6242-W. Oct. 27, 1922. 1 p.
Photographs, blueprints.
Description of the Bleriot Spad 41, equipped with a 300 H . P . Hispano
Suiza engine. M. I. D. 2081-346/ 4. France 6243-W. Oct. 27, 1922. 1 p.
Photographs, blueprints.
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New Books and Documents
Air Service T-2.
Preliminary report on Fokker transport equipped with Liberty 12 en­gine.
McCook Field. July 18, 1922. 1 p.
Engineering Division TP-1.
Structural design of TP-1 fuselage; by B. C. Boulton. Airplane Sec­tion.
McCook Field. May 1, 1922. 21 p. Diags.
Bodensee.
AIRCRAFT.
(Lighter-than-air.)
Photographs of the Zeppelin passenger carrying airship Boclensee. n. cl.
ARMAMENT.
Bombs.
Handbook on internal bombrack mechanism. 1922. .30 p. Photographs, .
drawings.
EQUIPMENT.
Electrical.
Report on work covered at th~ Bureau of Standards on special life tests
of electric lamps, electrical safety code, static electricity, etc. Nov. 9, 1922.
P. 22.
INSTRUMENTS.
Compass.
Earth inductor compass by P. R. Heyl and L. J. Briggs. Bureau of
Standards. 1921. 27 p. Photostats, diags.
Swinging of compasses in aircraft. Canadian Air Force. Ottawa,
Canada. Technical Memo. No. 38. 3 p.
Indicator.
Report of the micro-indicator for the testing of high speed engine; 0 .
Mader. In German with translations. Reprinted from Dinglers Polytech­niches
Journal. n. cl. 49 p. Photostats, photostatecl drawings.
Preliminary report on electrical indicator for high speed internal com­bustion
engines. Royal Aircraft Establishment report E. 2197. Jan. 16, 1920.
7 p. Photographs, drawings.
Sextant.
Description of the Douglas Appleyard Arcless sextant. National Ad­visory
Committee for Aeronautics. Nov. 27, 1922. 1 p.
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Compass
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Compass
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Micro­Indicator
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Pressure
Indicator
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Sextant
New Books and Documents
Report on Fischer pendulum sextant, submitted in connection with the
instrument development program. Bureau of Standards. Nov. 29, 1922.
3 p. Photograph.
Tachometer.
Report of favre-Bulle centrifugal tachometer, submitted by Engineering
Division, McCook Field, on Oct. 3, 1922. Bureau of Standards. Nov. 21,
1922. 3 p. Photographs, chart.
- MATERIALS.
General.
List of British standard specifications for aircraft materials and com­ponents.
British Engineering Standards Association. Nov., 1922.
Caustic magnesia cement. Bureau of Standards. Circular No. 135.
Oct. 16, 1922. 14 p.
Reclamation of used petroleum lubricating oils; by W. H. Anderson.
Bureau of Standards. Technologic papers No. 223. Oct. 21, 1922. 16 p.
Metals.
Soldering of aluminum and its alloys; by Gino Galo. Navy Dept. Bureau
of Aeronautics. Technical Note No. 231. Nov. 15, 1922. 6 p.
Fatigue resistance of duralumin for Verslagcn in Verhanclelingen van
den Rijks-Stuclieclienst voor de Luchtvaart, 1921, Part 1, report for M17 A.
National Advisory Committee for Aeronautics. Sept., 1922. 15 p. Diags.
Magnetic susceptibility and iron content of cast reel brass ; by L. H.
Marshall and R. L. Sanford. Bureau of Standards. Technologic papers No.
221. Sept. 27, 1922. 14 p. Illus., charts.
Preliminary report on the properties of commercially pure nickel as a
standard material for fatigue investigations, by G. A. Hankins. Aeronau­tical
Research Committee. Reports and Memoranda No. 789. (M. 11).
Nov., 1921. 8 p. Charts.
Effect of temperature, deformation, and rate of loading on the tensile
properties of low-carbon steel below the thermal critical range; by H. J.
French. Bureau of Standards. Technologic papers No. 219. Aug. 22, 1922.
57 p. Illus. charts.
Paints, Coatings, Etc.
British standard specification for aluminum paint. British Engineering
Standard Association. X. 22. Sept., 1922. 3 p.
British standard specification for identification paints for pipe lines.
British Engineering Standards Association. X-25. Sept., 1922. 2 p.
United States specification for gum spirits and wood turpentine. Bureau
of Standards. Circular No. 86. Eel. 2. Oct. 6, 1922.
Protective metallic coatings for the rust proofing of iron and steel.
Bureau of Standards. Circular No. 80. Eel. 2. Sept. 2, 1922.
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Paint
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New Books and Documents
PHOTOGRAPHY.
Surveying with aircraft photographers; by Maj. J. W. Bagley. Meet­ing
of \iVestern Society of Engineers. Sept. 6, 1922. 19 p. Photographers.
Exactness of topographical survey by aid of aero-topographical photo­graphs.
Results of a comparative survey between the plain-table tachometry
and the autocartography after Professor Hugersoffs' method, made by the
Ministry for topographical survey, topographical survey of Saxony. 1921.
17 p. Photostats.
Elektrische methoden der momentphotographie, M. I. D. 2172-809/ 1.
France 6280-W 1915. 103 p. Illus. diags. By Dr. Bruno Glatzel.
Theory, construction, and use of the photometric integrating sphere; by
E. B. Rosa and A. H. Taylor. Bureau of Standards. Scientific papers No.
447. Aug. 28, 1922. 45 p. Illus. charts.
Contents:
1. Construction and use.
2. Theory.
Spectrophoto electrical sensitivity of bournonite and pyrargyrite; by W.
W. Coblentz and J. F. Eckford. Bureau of Standards. Scientific papers
No. 451. Oct. 3, 1922. 20 p. Charts.
Test of bromotype samples submitted by Fairfield; by S. M. Burka.
Nov. 2, 1922. 1 p.
POWER PLANT.
General.
Guide to the care and mamtenance of aero engines, stationary, radial,
and rotary. Air publication No. 394. Air Ministry. Apr., 1921. 25 p.
Reeport of the oil-engine nomenclature committee. Institution of Me­chanical
Engineers. Nov. 27, 1922. 4 p.
British standard specification for drain cocks, water or oil. British En­gineering
Standards Association. A. 11. Sept., 1922. 3 p.
Endurance test of Ordnance lock nuts for use on cylinder hold-down
studs. M'f'd by Ordance Engineering Co. Power Plant Section. McCook
Field. July 8, 1922. 2 p.
Liberty.
Test No. 339 on dural auxiliary drive gears for Liberty engine; by Aero­nautical
engine. Laboratory. Navy Yard. Oct. 16, 1922. 3 p. Photo­graphs,
blueprints.
Panhard.
Description of 500 H.P. Panhard Levassor, type VI2M. M. I. D. 2081-
368. France 6220-W. Oct. 23, 1922. 2 p.
Rolls-Royce.
Correct method of assembling friction anchorage of Rolls-Royce Eagle
VIII. Notice to ground engineers No. 11 of the year 1922. Air Ministry.
Nov. 8, 1922. 1 p .
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Engine Parts
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Liberty
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Panhard
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1922-No. 11
New Books and Documents.
Wright.
Report on master connecting rod from the \ i\T right radial engine, sub­mitted
by Power Plant Section; to determine cause of fai lure. Material
Section. McCook Field. Nov. 2, 1922. 3 p. Photog-raphs.
Information for Briti sh attache on ·wright radial engine 1922. 2 p.
Fuel System.
Proper gasket material for vertical duplex fuel pump. _ War Dept. 0. C.
.A. S. Letter of instruction No. 67. NoY. 2, 1922. 1 p.
Lubricating System.
Oil pressure gage connections. Navy Dept. "Bureau of Aeronautics.
Technical order No. 20. Nov. 6, 1922. 1 p.
PROPELLERS.
Boerner.
Correspondence, patent specification and pamphlet on Boerner ,propeller.
Tn Dutch and English. 1922. 20 p. Illus.
Leitner Watts.
Test of Leitner Watts propeller in endurance flight made by M. M.
Bossoutrot and Drohen in a Farman Goliath. M. I. D. 2083-560/ 1. Eng­land
14505. Oct. 17, 1922. 2 p.
RADIO.
Electron tube amplifier using 60-cycle alternating current to supply
power for the filaments and plates; by P. D. Lowell. Bureau of Standards.
Scientific papers No. 450. Oct. 2, 1922. 8 p. Diags.
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