Technical bulletin no. 49. Development of military aircraft for the United States Army Air Corps under supervision of Engineering Division

              AIR CORPS INFORMATION CIRCULAR
VOLUME VI
(AVIATION AND AEROSTATION)
BY DIRECTION OF CHIEF OF AIR CORPS
THIRD QUARTER - 1926
TECHNICAL BULJLETIN
No. 49
DEVELOPMENT OF MILITARY AIRCRAFT .
FOR THE UNITED STATES ARMY AIR CORPS
UNDER SUPERVISION OF ENGINEERING DIVISION.
Prepared and Published
By Direction of the Chief of Air Corps
and under the supervision of
JOHN F. CURRY, Major, A. C.,
Chief of Engineering Division.
M cCook Field 10-4-26-lM
NUMBER 575
CO~FIDENTIAL
The information contained herein is confidential and therefore
must not be republished, either as a whole or in part, without
express permission of the Chief of Air Corps, U. S. Army.
CONTENTS
AIRCRAFT DEVELOPMENT
AIRPLANES
Experimentation with Pursuit Aircraft ........................ ...................................................... . 7
More Pursuit Airplanes Ordered........ ...................... ................................................ ............... 7
Curtiss 0-1 and 0-lA ............................ ........................ .. ................................ ... .......... ............ 8
Changes in 0-6 Airplanes ............................................................... .......................................... 8
Change in Designation of Douglas Cargo Airplanes............... ................. ................... 9
Service Tests on LB-1 Airplanes ............................................................................. ................ 9
Amphibians for Pan-American Flight ... ................. .................... ............... ............................ 9
Aerodynamical Investigations Cornp l ~ t e cl ........... ..................... .............. .. .......................... 10
Controllable Pitch Propeller.................................. ........................ .......................................... 10
New Propeller Test Laboratory for Wright Field .. ......................... ..... .......................... . 10
AIRSHIPS AND BALLOONS
Lighter-Than-Air Equipment for Service T est .......... ............. .... ............................ ......... 10
Helium Purification Plant o. 1....... ... ........ .. ... ................... ...... .................... ....................... 13
1\RMAMENT
Elimination of Blast Tubes ..... . 14
'Train Bomb Release Handle, Type B-1 ............ ..................... .................................. ... 14
Gun Sights .................................. .......................................................................... ............ .......... 15
Flexible Mounting of the Browning Aircraft Machine Gun................................................ 16
EQUIPMENT
Aerial Tow Targets .... ........ ................. ........ ................ ................. ................. ................. ........... 17
P!·oposed Heavy Duty Field Service Truck........ ...... ............................................................. 18
Aircraft Engine Starters .................. ....... ................. ................................................ .............. 18
Fire Extinguii;hers for Service Test..................................... ..... . ............. ................ 20
POWER PLANTS
First Curtiss VG-1550 Engine Completes 50-Hour Test......... ............... ... ............. 21
Packard New Series 2A Engines Received......... ............ ............................ .............. 21
Changes in Liberty Model V-1410 Air-Cooled Engines ....... .... ........................... 22
Automatic Mixture Control ............... .. .......................... ..................... ... ... .............................. 22
Nickel-Plated Aluminum Fuel Tanks Unsatisfactory ..................................... ................. 24
Scintilla Magnetos ............................................... .......... ........................................................... 24
The New Pivotless Type Magneto Contact Breaker .................................................. ......... 24
C 0 N T E N T S - (Cont'd)
RESEARCH AND EXPERIMENT.
RESUME' OF ENGINEERING DIVISION SERIAL REPORTS.
Roll, Yaw and Rudder Moments on Douglas C-1 Airplanes (S-2676) _______ _
Additional Wind Tunnel Data on Huff-Daland XLB-1 Airplane (S-2683) ______ _
25
25
Wind Tunnel Test of Proposed Verville-Packard Pursuit Airplane (S-2685) ________________ 25
Wind Tunnel Test of Model of Boeing PW-9 Pursuit Airplane (S-2686) _____________ ________ 25
Strength of Bent Struts (S-2692) ________________ ---------------------- ---- -----------··------------- _____ __ 25
The Extended Induction Theory (S-2694) --------------------------------·--------- ______________ _
Wind Tunnel Test of Model of Proposed Reconnaissance Airplane (S-2698) _______ _
Interference Tests on DH-4B Model and Propeller (S-2699) _________ _
Driftmeters for Pursuit Airplanes (S-2661) _______________________ _
Test of Herzmark AV-2 Starter for Liberty Engine (S-2664) ____________________________ _
Test of Purox Liquid Oxygen Vaporizer (S-2688) ______ _
Insulating Material for Liquid Oxygen Vaporizers (S-2689) ----------------
Brandis Octant with Willson Telescope (S-2696)
24-Inch Revolving Incandescent Beacon, A. C. Type B-3 (S-2697) _____ _
Performance Test of Huff-Daland AT-2 Airplane (S-2678) _____ ____________________ _
26
26
26
26
27
27
27
27
28
28
Use of Darwin Yaw Meter in Measuring Air Flow (S-2684) .---------------------------·---·-------- _ _ 28
Performance Test of Thomas-Morse X0-6 Airplane (S-2691) ___________________________ _ 28
Aviation Engine Descriptions and Performance Curves (S-2407 r evised) ___ __ ____ __ 28
Light Oil Tests for Curtiss D-12 Engines (S-2674) ______________ ---------------------- 28
Jl1et.hod of Conducting Acceptance Test of Turbo-Superchargers (S-2679) _________ 29
Carburetor Metering Jet Calibration (S-2681) -------------- ----- --------·------·---- -----------·-- -- 29
INVESTIGATION OF MATERIALS
Portable Welding Apparatus on Service Test ___ ------ --------------·- 29
Airplane Dope with High Gloss Finish __________ -----------·-· ··----- ------- -----------·--------- 29
Rubber Lumber and Rubber Paint --------------·-----------·-------------------- -·--·-------------- -------------------- 29
NEW BOOKS AND DOCUMENTS.
Additions to Engineering Division Technical Files During Third Quarter, 1926__________ 30
Accessions to Engineering Division Technical Library __________ _ ----·--------------------- 34
LIST OF ILLUSTRATIONS
Cabin of Douglas Cargo Airplane Converted Into Ambulance______________________ _______ _____________ 6
Helium Purification Plant- Car No. L -··--···-·--········---·--·--·-···----· _ -- -·-·----········-·----·· --··------- ·- 12
frain Bomb Release Handle, Type B-L--···--·---··-····-·-··-----··-···-·--···-------········-·--- ·-·---- ···---------·· 15
Flexible Mounting of Browning Aircraft Machine Gun ______ ········-··-····················-------------- 16
New Combination Electric and Hand Inertia Starter, Type C-5--------·-·-- ·-----··············-···- 19
Eclipse Hand-Operated Inertia Starter ---- ---- -·---······-···-··-·······--···--··---········-···-·····-·····---·---··· 19
High Pressure Injection System of Heywood Air Starter ··-·----- ·------··--··- ·----------··----------·· 20
Curtiss VG-1550 Aircraft Engine -·· -----····----·········-··-·--------·-··------- -----------··--------- -- --·--·-·-·---·- -· 21
Automatic Mixture Control for NA-Y5D Carburetor ····-··-·------· ---------·----·--- ··- --------------·---- 22
Schematic Layout of Automatic Mixture Control on NA-U6A Carburetor -- ------····---·--·· 23
Manually Operated Mixture Control Valve ---···--··----·-··-·---·-······--·-----·---·--··· ····· -------······--·--·· 23
J\iew Pivotless Type and Conventional Lever Type Magneto Contact Breakers .... ________ 24
Portable Welding Outfit ---····-···-----····-----······-··-·-·····--------------------------------·--·--·-------·---·········---·- 29
6 T E C H N I C A L B U L L E T I N N o. 49
CABIN OF DOUGLAS CARGO AIRPLANE CONVERTED IN TO AMBULANCE.
(See Page 9.)
AIRCRAFT DEVELOPMENT
ON ENGINEERING DIVISION PROGRAM
AIRPLANES
Experimentation with Pursuit Aircraft.
In connection with supercharged pursuit development, the Boeing Airplane Company has ef­fected
the installation of the Packard 1500 engine ( 510 h. p. at 2100 r. p. m.) with 20,000-foot
side type supercharger in a remodelled PW-9A airplane. The remodelling involved a redesign of
the wings, a rearrangement of the wings and equiptilent, and the mounting of fixed machine guns
on the lower wing. Upon delivery the airplane was found to be heavier than antici pated and with
its center of gravity located farther forward than originally contemplated. This necessitated ex­perimental
flights with ballast to determine whether the ai rplane was satisfactorily ba!anced. The
flights were made with reduced fuel load and disclosed binding of the control surfaces with the re­srnt
that proof-load tests of wings and stabilizer we1-e made to determine cause of the binding be­fore
attempting performance tests. It was found desirable to acid a rear li ft truss bracing, and
the tests are being delayed pending in stallation of this truss.
For the purpose of developing a new type of pursuit, the above manufacturer has also con­structed
at his own expense an experimental airplane about the inverted Packard 1500 engine,
uti li zing certain government owned equipment furni shed under Air Corps Contract 915, as stated
in Tcclm-ical Bulletin No. 45. This ai rplane is completed and ready for performance tests at the
manufacturer's plant as soon as the engine becomes available.
In determining possible appli cations of the air-cooled vee type engine, one of the Curtiss P -1
pursuit airplanes now on service test was fitted with an inverted air-cooled Liberty V-1410 engine
for experimentation. This airplane, to which no particular designation has been assigned, attained
an indicated high speed of 168.5 miles an hour without full load. The installation was made by the
Engineering Division to obtain comparative engineering data on performance and head resistance
of air and water-cooled vee type engin es.
The above airplane. equipped with inverted air-cooled Liberty engine and special shock ab­orbing
landing wheels. was exhi bited at the National Air Races at P hiladelphi a. Pa.
Application of the air-cooled radial engine has been tried out in one of the production Curtiss
P-lA pursuit airplanes manufactured under Air Corps Order 2644. This airplane, designated Model
XP-3. is fitted with 9-cylinder Curti ss R-1454 air-cooled radial engine (400 h. p. at 1650 r . p. m.),
as stated in T echnical Bulletin No. 46. The accessory equipment includes hand starter, booster
magneto and built-in supercha rger.
More Pursuit Airplanes Ordered.
A production order (Cont. W-115-AC-3) has been placed with the Curtiss Aeroplane & Motor
Company for twenty-five airplanes of an improved P -lA type, to be designated .Model P-l B. These
articles wi ll be equipped with Curti ss D-12-D engines ( low compression 435 h. p. at 2300 i-. p. m. )
and larger landing wheels, size 32x6. Structural improvements involve a lowering of the pilot's
seat to provide greater comfort from the slipstream, strengthening of the fuselage fitting to permit
carrying of two 100-lb. bombs, and 1-einforcing of the radiator side walls to withstand vibration. A
new chassis will be provided to accommodate the larger wheels. Additional equipment not stan­dard
on present P -lA airplanes will include an Eclipse inertia type hand sta rter and provi sion for
installation of parachute fla1-es and SCR-133 radio set.
8 T E C H N I C A L B L L E T I N N o. 49
For economical reasons it is unlikely that a recent decision to discontinue the use of nickel-plated
aluminum fuel tanks (see page 24) will apply to all of the new P-1J3 airplanes, inasmuch as fab­rication
of some of the tanks had already begun when th is chang-e was decided. In all future require­ments,
however, the use of tinned steel or brass tanks is advocated. A new feat ure incorporated
in the P- lB tanks is the provision for a water sump in the bottom of the tank of about one pint
capacity with the outlet lines protected with screens. All P-lB tanks will be leakproofed with rub­ber
covers.
Curtiss 0-1 and 0-lA.
Ten 0 -1 observation airplanes manufactured by the Curtiss Aeroplane & Motor Company were
allocated for service test as two-seater pursuits, owing to high performance qualities di splayed by
the experimental a rticle. Two articles, equi pped with ballast tanks in the tail of the fuselage, were
assigned to McCook F ield fo r test. One of these was fitted with a special wing flap in center
section trailing edge as a means of improving longitudinal balance. Consensus of opinion regard­ing
the use of the flap indicated that an adjustable stabilizer was superior for the purpose, at least
in this particular airplane, and that an adjustable elevator would prove even more effective.
Following tests as two-seater pt11:suits these airplanes were reallocated for service test as ob­servation
types.
In conjunction with service tests of 0 -1 airplanes with Curtiss D-12 engines, an airplane of
this type was equipped by the manufacturer with a standard Liberty engine under the designation,
Model 0 -lA. This a rticle was then flown to Mc.Cook F ield fo r performance te ts and examination
by a Board of Officers convened to consider ground attack aircra ft. As a re ult, quotations have
been invited for conve1-sion of 0 -1 airplanes with D-12 engines into 0-lA airplanes with Liberty
engines in accordance with the revised Air Corps specifications. T he type of fu selage and cockpit
to be provided in future production a rticles wi ll be decided later by the Observation Board which
convenes at McCook F ield early in the next quarter. The present specificat ion is based upon the
shallow fu selage a used in the present a rticle.
Comparative performances of the Curti ss 0-1 and 0-lA observation airplanes with Curti ss
D-12 (448.5 h. p. at 2320 r.p.m.) and Liberty (430 h. p. at 1750 r. p. m. ) engines respectively are
as follows:
High speed at ground ( 111.p.h .j1-.p.111. ) .
H igh speed at 10,000 feet ( m.p.h./r.p.m .)
T ime to climb to 10,000 feet ( min. ) . . .. . . . .
Initial rate of climb (ft./ min .) .
Service ceiling (ft.) .. . .. . .. . .... .
0-1
143.2/ 2320
135.5/ 2190
13. l
1070
17.375
0-JA
147.8/ 1750
136.8/ 1645
12.6
1130
17.040
Additional tests wi ll be made on the 0-1 A airplane to determine what type of propeller glves
the best performance.
Changes in 0-6 Airplanes.
T he first experimental X0-6 all-metal observation airplane, constructed under Air Corps Con­tract
818, has been returned from the Thomas-Morse Aircraft Corporation with certain changes in­corporated
therein to improve flying qualities, principal among whi ch is the slight stagger in the
wing setting. F light tests di sclosed that this stagger caused longitudinal in stability, because it had
been obtained by moving the upper wing fo rward. a position that changed the center of gravity with
reference to the wings. T he stagger was consequently removed, and the airplane retested.
Subsequent tests showed that balance could b maintained at all speeds in level Right by adjust­ing
the stabilizer. and at speeds other than those compensated for by the tabili zer setting by apply­ing
additional adver e force on the control stick. Both ailerons and rudder were found over-bal­anced
and the elevator and rudder actions quite stiff. Obviation of these difficulties presumed re­duction
of the rudder balance area, relocation of hinges on both rudder and ailerons, and easement of
elevator action thru removal of positive stagger.
A IR C R A FT D EVE L O P MEN T 9
At pre ent construction of only one of the four remaining 0 -6 airplanes on this contract is au­thori
zed. In the main the modificati ons in this article ( the second ) include the incorporation of
Frise type ailerons and elevators, reduction of rudder balance and eliminati on of stagger. Upon
completion the contractor will conduct preliminary flight tests at his plant to determine whether the
changes have accompli shed the desired result.
Change in Designation of Douglas Cargo Airplanes.
In consequence of a number of miscellaneous changes to be incorporated in the seven production
cargo airplanes being furni shed by the Douglas Company under Air Corps ·ord er 26377, and the
fact that these airplanes will be built in conformity with the revised Air Corps specification, the
model designation ha been changed to "C-lC" instead of "C-1" as previously stated in Tcclmfral
Bulletin No. 47.
A Douglas C-lA cargo airpl ane has been conditioned for experiments at Aberdeen P roving
Grounds in connecti on with night anti-aircraft tests. The airplane is equipped with a Liberty geared
engine and exhaust silencers having long tail pipes extending to a point midway between the wings.
The original intention to reverse the short silencer outl ets upward was abandoned after tests dis­closed
that excessive quantities of exhaust gas were deflected into the cockpit. The purpose of the
tests is to determine whether airplanes thus equipped would decrease or entirely eli minate the possi­bility
of their presence being detected by sound locater instrument now used by the anti-aircraft
service. The airplane was also equipped with a tow target mechani sm and complete night-Rying
equipment.
Another Douglas cargo airplane was converted into an ambulance airplane for exhibition at
the Sesqui -Centenni al Exposition at P hi ladelphia, Pa., in connecti on with a convention of medical
doctors. In the cabin of the ai1-plane accommodations were arranged fo r a Right surgeon and two
patients on improved type litters.
Service Tests on LB-1 Airplanes.
P reliminary service tests on LB-1 airplanes recently delivered by Huff Daland Airplanes, Inc.,
on Air Corps Order 2686 disclosed several defici ences ari sing from transmittal of engine vibrations
to the airplane structure. Those assuming serious proportions were fuel li ne fail ures at poin ts
where vi bration was greatest. Immedi ate reli ef was effected by temporarily changing the fuel
system in the second and third articles f rom pump to gravity feed, until a rearrangement of fu el
lines could be worked out and a means found to eliminate vibration. \ i\Tith a rearranged system as
since devised . it will be possible to retain the pump system in the seven remaining arti cles, thereby
assuring adequate fu el head under all conditions of Right.
An attempt to damp engine vibrati ons thru the use of felt pads between the engine and the
bearers proved ineffective, and as a result two types of rubber pads will be tri ed on the remaining
airplanes.
Investigation of structural rigidity occasioned by reports from the service that weaving of
fuselage and wings occurred in fli ght with sudden accelerations of the engine di sclosed that this
infrequent condition was not dangerous. As a precautionary measure, however, certain structural
members were reinforced or replaced and other minor corrective measures applied as determined
in tests of the fourth a rt icle at McCook Field.
In connection with the development of a shock absorbing engine mount for the Packard 800-
h. p. engine in this airplane, the services of the Westinghouse E lectric & Manufacturing Company
have been solicited. This work wil l involve all necessary research in developing an elastic engine
bearer.
Amphibians for Pan-American Flight.
Six of the fifteen production OA-lA amphibians recently ordered from the Loening Aero­nautical
E ngineering Corporation have been allocated for the proposed Pan- meri can Right to be
attempted shortly under auspices of the Army Ai r Corps. Only five of these amphibians, however,
will actually pa rti cipate in the Right, as the first article will be used fo r testing equipment and for
rese rve.
10 T E C H N I C A L B U L L E T I N N o. 49
No military equipment will be carried on this Right, but certain special features are provided as
fo llows: additional fu el and oil tankage by in stallation of a 60-gallon auxilia1-y tank in hull under rear
cockpit and proportionate increase in oil capacity; increased cooling surface by use of a larger
radiator ; a supply of drinking water which by an ingenious arrangement can be pumped in emerg­ency
into the engine cooling system ; and a new landing gear operated by hand. T he latter will be so
designed that it may be easily raised or lowered by twelve turns of a hand crank, the weight of the
chassis being counterbalanced by rubber cords.
Additional equipment includes a 30-pound anchor and a Type D-3 refueling pump having a
capacity of 1000 gallons an hour.
Improvements common to all production articles on this contract involve a general deepening
and strengthening of the hull and keel, rai sing of the propeller thrust ax is to permit use of a larger
propelle1-, and the relocation of the expansion tank in leading edge of upper wing center section in­stead
of in the engine vee a fo rmer ly install ed.
Aerodynamical Investigations Completed.
The fo llowing aerodynamical investi gations have been completed, and the reports are now m
preparation :
1. Study of P ressure Distribution.
2. Study of Torsion in v\Ting F ramewodc
3. Effect of Aging on Duralumin.
4. Study of F lutter in Monoplane \ i\Tings.
5. Special Static Test of XHB-1 Wing Panel.
6. Static Test of Longren P apier-Mache F uselage (For Navy Department ).
Controllable Pitch Propeller.
A controllable pitch propeller with metal blades has been developed for the Liberty engine.
The new propeller, five of which have been orde red for ervice test, has successfully passed both
whirling and fli ght tests.
The introduct ion of the detachable blade metal propeller has greatly simplified the problem of
changing the pitch of a propeller in Ri ght, and it is expected that much progress will be made with
this device in the near future.
New Propeller Test Laboratory for Wright Field.
Present plans for the new propeller test laboratory under construction at \ i\T right Field call for
the erection of the largest and most complete laboratory of this kind in the world. W hen com­pleted
this unit will be three times larger than the present whirling test laboratory at McCook Field
which has been in operation for several years. Foundations for the buildings an I electrical ma­chinery.
some of which has been delivered, are under way.
AIRSHIPS AND BALLOONS
Lighter-than-Air Equipment for Service Test.
The following equipment has been distributed to vari ous lighter-than-air act1v1t1es fo i- service
test to determine what requirements are necessary for the ultimate design of standard service unit.
BARRAGE BALLOO s, TYPE D-2. Three high a ltitude barrage balloons, Type D-2, have been
ordered from the Goodyear Tire and Rubber Company fo r service test, as reported in T echnical
Bulletin No. 47. These balloons will be patterned after the second experimental model developed
by the E ngineering Divi ion early in the year. In this design, the expanding lobes used in the first
experimental barrage balloon were replaced by dilatable gores in the envelope to care for the ex­pansion
of gas that occurs with altitude. Stability of the envelope was secured by means of three
air-filled lobes. built up in a er ies of intersectino- truncated cones with common apex and with their
bases in the envelope. The lobes are non-expanding.
AIRCRAFT DEVELOPMENT
The principal characteristics of the service test a r ticles are as follows :
Volume of envelope with hydrogen, contracted
Volume of envelope. fully expanded .
Volume of lobes ( three) . . .... . .
Shape of envelope . . . . . . . . . . . . . . . . .
Height of envelope
Diameter of envelope
Weight of fabric (Single P ly) .
:Method of suspension .
] iameter of cable ... .. ........ . .
Designed altitude (maximum) .... . . . ....... .
15,000 cu. ft.
23,700 cu. ft.
2,300 cu. ft.
A-P
49 ft . 6 in.
31 ft. 7 in.
6 oz./ sq. yd.
Catenary
1/ 8 ( 7x l9)
15.000 ft.
11
H1GHLY MOBILE BALLOON vVINCH, TYPE A-2. After more than two years experimentation.
the highly mobile balloon winch, Type A-2, manufactured by the Steel Products E ngineering Com­pany,
Springfield, Ohio. under Air Corps Contract 649, has been released to Scott F ield fo r service
test. This winch is an improved model of the Type A-1, previously tested at Scott Field, and in­corporates
a 180-h. p. Sea Gull six-cylinder engine and other improvements designed to give in­creased
hauling speed, greater ease in shi £ting winch transmission, and simplified operation.
The present hauling peed of the Type A-2 winch is 1200 feet a minute with a 50,000-cu. ft.
observation balloon. or 1600 feet a minute with a Type R observation balloon, against a cable ten­sion
in excess of 2.000 pounds. \ i\Tith the French Caquot winch. used extensively by the Alli es dur­ing
the vVar. the max imum hauling speed with a Type R Caquot bal loon was only 1200 feet a minute
in calm air or 800 feet a minute with cable tension not exceeding 2200 pounds.
Gear shifting in lXesent types of winch transmi ssions is a slow procedure. necessitating the use
of brakes to stop the balloon while the shift is being effected. In the highly mobile winch , however.
a special transmission is provided, by means of which it is possible to shift from high to low speed
or vice versa without cessation of hauling power on the balloon cable and without stopping the bal­loon.
The change is effected so smoothly that the occupants of the basket are scarcely aware of the
fact. To provide simplicity of operation. the spooling of the cable on th e storage drum of the highly
mobi le winch is made entirely automatic th ereby permitting the driver to devote hi s entire attention
to manipulating the balloon from his seat fac ing the cable.
Although the Type A-2 highly mobile winch weighs 12,000 pounds, it is capable of sustaining
a speed of 35 miles an hour over good roads and has adequate climbing ability to negotiate steep,
rough or marshy terrain. This performance has been accomplished through the use of a four­wheel-
drive chassis having special inbuilt feat ures to facili tate steering and to prevent binding under
any conditions of fl exure li kely to be encountered in service. T he low center of gravity. consistent
with road clearance. enables the winch to be tilted sideways to a greater extent than other types.
without overturni ng.
It is proposed to conduct parallel tests on the highly mobile winch and the American Caquot
winch to determine which type is best adapted for service requirements. Descriptions of both types
will be found in T echnical Bulleti11 No. 42.
AIRSHIP MANEUVERING \i\TINCI-I, TYPE B-1. T he airship maneuvering winch, Type B-1, a
caterpillar vehicle manned by two men, was designed to effect the ground handling of airships by
mechanical means. thus obviating the employment of large landing crews. As originally designed,
three yea rs ago, it incorporated a grab winch mechanism which automatically grabbed the drag rope
when dropped from the ai rship. The grab mechanism, however, proved unsati sfactory and was ac­cordingly
replaced by a platform mounting a capstan driven by a power take-off from the trans­mission.
The 60-h. p. vVaukeska engine, which drives the caterpillar tracks through a fo ur- peed
transmi ssion having two speeds fo rward and two reverse, is mounted on the rear of the chassis. In
front of the engine are the seat and controls for the driver. T he platform in front of the dri ver
is thus left clear for the operator to manipulate the rope on the capstan.
The airship maneuvering winch and the highly mobile balloon winch were manufactured by the
Steel Products E ngineering Company of Springfi eld, Ohio. under the same contract. Both units
have been released to Scott F ield for se1·vice test.
-N
HELIUM PURIFICATION PLANT-CAR No. 1. z
0
A- Main Switchboard D-D- Air lnterchangers G-Expans ion Eng in e and Dynamome t er
B-Motor Contr ol Switchboard E-Leed-Northrupp H elium Recorder H- Air Compressor
C-Trans former F-He lium Interchanger or Column I- Impure Gas Intake
J- Helium Compressor K-K- Drying Bottles
AIRCRAFT DEVELOPME T 13
ArnsI-I lP BLOWER UNIT, T YPE A-1. The Type A-1 blower is an electric-driven unit, primarily
developed fo r use on the U . S. M. B. airship as an emergency means of inAating the ballonets in
event of failure of the power plant to supply them with air through the scoops. Inasmuch a this
airship was surveyed before the development was completed, it was decided to te t the blower on the
TA and TC airships to determine its adaptability to large airships. The delivery of the blower,
although small for this size airship, is believed to be suffi cient fo r maintai ning envelope pressure in
an emergency landing or during a period of fo rced inactivity resulting from engine failures .
The blower unit consists of a 12-inch, 8-bladed fan type propeller of modified RAF-6 section.
driven as a left-hand pusher by a small 10-volt D. C. electric motor. T he motor operates at 3600
r. p. m. with current supplied from a 12-volt battery ci rcuit. commonly used in present ai rship elec­trical
systems. For this reason a special battery install ation is not required. The complete unit
weighs 52 pounds and deli vers 2,000 cubic feet of air a minute through a 15-inch outlet at a pres­sure
of 0.50 inches of wate1-.
Helium Purification Plant No. l.
The Helium P urification Plant No. 1, ill ustnited herewith, compri ses a complete unit for purify­ing
helium gas that has become impure thru continued use in airship or otherwise contaminated.
The plant was planned by the Office of the Chief of Air Corps. designed by the Bureau of Mines.
and built by the Engineering Division as a mobile unit for transportation by rail to lighter-than-air
activiti es.
The method of purification employed in thi s plant is known as the "Liquefaction Process," that
is, the impurities are separated from the helium by extraction after being liquefied.
The plant is mounted and completely housed in a standard railroad box car, th e entire unit
weighing approximately 120.000 pounds. It is dependent fo r operation upon water and electric
power supplied from outside sources. E ither 220 or 2300-volt cun-ent may be used. a special trans­former
being provided to step clown the hi gher voltage. At maximum operating capacity about 335
amperes of current per hour at 220 volts are requi1-ecl. By employing two men the plant may be
operated continuously. except for such intervals as a re necessary to replace the potassium hydroxide
used in removing moisture and carbon dioxide from the helium and aii· cycles.
The major equipment comprises the following items : two compres ors, one for air and one for
helium; ten drying bottl es. fou r for air and six for helium ; one expansion engine: four interchangers.
two fo r air and two for helium; one current transformer; and two switchboards which control opera­tion
of the entire plant.
The compressors. each of which is driven by a 50-h. p. electric motor, absorb a total of 98.5
horsepower. 52.5 h.p. for the air cycle and 46 h. p. for the helium cycle. Each motor is equipped
with a starting controller and two remote control cut-out switches for shutting down eithe1· or both
compressors in emergency. Each compressor consumes about 0.04 gallons of crankcase oil per
hour and about 0.015 gallons of high-Rash-point lubricating oil per hour. The air compressor has
a capacity for handling 10.000 cubic feet per hour. The expansion engine developes approximately
four hor epower per hour.
The liquefaction process by which the helium is purified may be summari zed as follows: Air
at atmospheric pressure is drawn into the compressor where it is compressed to 600 pounds pressure
per square inch. It is then passed at this high pressure thru a series of drying bottles, fi lled with
potassium hydroxide for removing moisture, to the expansion engine where it is again expanded to
atmospheri c pressure, the expansion producing the necessary low temperatures or refrigeration
for liquefaction. Once the air cycle reaches the lique fact ion temperature. the same air is recircu­lated
to avoid the necessity of removing moisture from fresh incoming air.
T he helium gas is taken into the compressor from gas holders or from the a irshi p envelope
at atmospheric pressure or from gas cyli nders at high pressure by the use of two reducing valves.
The impure gas is then compressed thru its cycle at 2000 pounds pressure per square inch, first
passing thru the drying bottles to remove all moisture. The dry gas is then brought under the in­Auence
of the refrigeration derived from the air cycl e, which liquefies the impurities and permits
their removal from the gaseous helium by extraction.
14 r E C H N I C A L B U L L E T I N N o. 49
The liquefiers and helium interchangers are contained in a thermally in sulated cabinet or
"column", with mineral wool as the in sulating material. Thermo-couples are in stalled in the col­umn
to permit temperature readings at various stages of the process. The column is also fitted
with a level gage of special design based on the thermo-conductivity principle to measure the
amount of liquid impuriti es in the purifier pot.
pon completi on of the cycle. the purified helium is di scharged at a pressure of 2000 pounds.
or more if desi1-ecl, in order that it can be either released into a gas holder or compre eel directly
into storage cylinders. T he capacity of the plant is 5000 cubic feet of impure helium per hour,
the purified gas averarring 97.8 per cent purity, as recorded by a Leed & Northrupp helium recorder
adapted fo r this installation by the Bureau of Standards.
F or prolonged operation at any station where conditions demand. consumption of water for
cooling the compresso rs is economized by recirculati on at an expenditure of only five horsepower.
The helium purification plant has given excellent results during several month operation at
Scott Field. Pri or to this impure helium at this activity was forwarded to Lakehurst for purification
by the Navy Department which retained the helium to all eviate transportation charges, and a new
supply of gas of 94 per cent purity was procured from the extraction plant at Fort \North. T exas.
By purifying helium at Scott Field a considerable saving in time and labor resulted. For in stance
it formely cost about 750.00 to transport a carload (about 550 cylinclers-95,000 cubic feet ) of
impure helium from Scott F ield to Lakehurst. exclusive of labor and expense required to compress
the gas into storage cylinders fo r shipment. Upon a rrival at destination it was then necessary to per­form
additional labor to di scharge the helium into a gas holder before the process of purification
could be started. T he cost of purifying helium at Scott F ield is app roximately $2.85 per 1000
cubic feet of pure gas from 85 per cent impure gas and $2.60 per 1000 cubic feet with 92 per cent
impure gas. The higher purity of gas obtainable from the purification plant also permits more ex­tensive
operations than were possible with helium o f lower purity obtained from Fort Worth.
ARMAMENT
Elimination of Blast Tubes.
F uture requirements fo r both .30 and .SO caliber synchroni zed machine gun in stall ations on air­cratt
call tor the elimination of the blast tube and the mounting of th e gun with its line of fire ap­proximately
in the contour of the cowl which, from the vicinity of the gun muzzle forward, will be
grooved or recessed. The cowl and other airplane parts wi ll be rein fo rced to with tancl the gun blast.
It has been determined that blast tubes, as used in present installations. cause inaccuracy of gun fire
clue to transmittal of vibrations to the gun and in some cases rnal functi on of the gun clue to stresses
imparted to the gun ba rrel jacket and fouling of the gun muzzle bearing by deposits from the burn­ing
gases momentarily confined in the blast tube.
Train Bomb Release Handle, Type B-1.
The train bomb release handle, T ype B-1. was developed to meet requirements fo r a power­operated
automatic train release handle for use in releasing bombs from internal bomb racks. The
escapement mechani sm of the release handle provides for the rel ea.sing of the bombs in succession
at uniform time intervals.
T he release ha ndle, as designed, is composed of two maj or units; namely, the power unit and
the control or regulating unit. The power unit consi t s of elastic shock abso rber cord s whi ch when
stretched furni sh th e energy fo r operating the release mechani sm of the bomb rack. T ension is
put on the cords before leaving the ground and is held in check by a stop on the control unit to
whi ch the power unit is attached by a flexibl e steel cable and pulley. T he control or regulat ing
unit consists of a gear train, one encl of which is attached to the power unit and the other connected
by sprocket and chain to the internal bomb rack. It has two handles for diffe rent settings on the
face plate, one for cont rolling the number of bombs to be dropped and the other fo r controlling the
interval between the dropping of the bombs.
AIRCRAFT DEVELOPME T 15
The "setting off" of the automatic release handle is effected either by hand or electrically by
means of a solenoid contained in the handle. When connected electrically to the Type C-1 or D-3
bomb sight, the train bomb release handle becomes truly automatic as the bomb sight trips the re­lease
handle at the proper time to hit the objective.
TRAIN BOMB RELEASE HANDLE, TYPE B- 1.
The experimental model which is undergoing test at McCook Field has successfully withstood
extensive ground tests for wear.
Gun Sights.
A gun sight, Type C-3, is under development for use in directing fire of fixed machine guns. In
principle, this sight is basically the same a the Type C-2 gun sight illustrated in Tec'111ical Bulletin
No. 46, and includes a provision for adjustment in the vertical and horizontal planes du1-ing flight.
Such an adjustment has been found necessary to compensate for flexure of the airplane structure re­sulting
from engine torque or other forces encountered in flight.
Tv,·o long range sight , Types H-1 and H-2. which may be mounted in standard 5/ 16 and 1/ 2-
inch sockets, have been developed for ground attack use. These sights for ranges up to 2000 yards
are normally employed in place of the rear sight of th~ present installation. the Type H-1 on the DH
airplane and the Type H-2 on other models.
A chin re t has been provided for use in connection with fixed gun sights requmng two or
three sets of mounts in the center of the cowl as installed in modern aircraft. The rest is so designed
that it may be mounted on a set of sight mounts and adjusted to accommodate different head posi­tions
desired by various pilots.
16 T E C H N I C A L B U L L E T I N N o. 49
Flexible Mounting of the Browning Aircraft Machine Gun.
Several means are under experimental development fo1· mounting both .30 and .SO caliber
Browning ai rcraft machine guns fl exibly on ring mounts. · Heretofore, the use of the Browning
gun in aircraft has been limited principally to fixed synchroni zed installations. The tentative ar­rangements
by which flexibility has been accomplished are briefly described in the follow ing :
- Fig. 2
-
Fig.4
,... Fig.5
FLEXIBLE MOUNTING OF BROWNING AIRCRAFT MACHINE GUN.
AIRCRAFT DEV ELOPME T 17
FLEXIBLE GuN lVIou NT, TYPES D-3 AND D-4. The Type D-3 and D-4 mounts were developed
for accommodating either single or double Lewi s and Browning .30 cal iber aircraft machine guns,
mounted flexibly. T he mounts are of the wind compensated ty pe, which combines flex ibility of the
ring mount .with ease of manipulation. Their superstructure are similar. the Type D-3 employing
standard cast aluminum rings equi pped with wind compensator and the Type D-4, spun cluralumin
rings equi pped with a combination vertical type wind compensator and back rest. This wind compen­sator
i capable of generatin g a turning pressure of approximately 90 pounds by utili zing a maxi­mum
spring pressure of SSO pounds, whereas former designs required a spring pressure of 1000
pounds to produce a pressure of 70 pounds. This feature reduces the effort required to turn a DH
ring mount from 80 to lS pounds.
Views of these mounts which have reached an advanced stage of development were publ ished in
Tech 11 ical B ulleti11 No . 47.
FLEXIBLE GuN :=-.1ot:NT, TYPE E-2. This mount (Fig. 1) was designed fo r the .50 caliber Brown­ing
machine gun. It is manually operated and provides for the use of standard fl exible gun sights.
The gun is controlled by means of the double spade grip as furni shed by the Ordnance Depart­ment.
Following the experimental tests it was found nece sary to redesign the mount to obtain
greater rigidity.
GuN ADAPTER Mourn, TYPE C-3. The Type C-3 gun adapter mount ( Fig. 2) has also reached
an ad vanced stage of development. This device consists of a yoke so designed as to trunnion the
gun on the center line of recoil when used on the standard ring mount. Link and shell deflectors
are included as part of the mount.
GuN ADAPTER MouNT, TYPE D-1. This adapter (Fig. 3) is designed to accommodate two .30
caliber Browning machine guns fo r flexible installation. In it the guns are positioned angularly to
bring the fulcrum as close as possible to the center line of recoil and a lso permit the mounting of
ammunition boxes on the guns. The adapter may be used with the standard ring mount and is
complete with all grips and trigger mechanisms necessary to control the guns.
GuN ADAPTER Mou wr, BALL SOCKET TYPE. A new type of gun mount based on the ball socket
principle is under development for mounting two 30 cali ber Browning machine guns flexibly. This
de ign is such that it requires the use of one gun with standard feed and another with a left and
right hand feed in order to position the trunnion close to the center line of recoil and provide fo r a
satisfactory method of feeding the ammunition.
AMM NITION BoxES, TYPE L-1 A ro L-2. To accommodate the flex ible installation of .SO and
.30 calibe1- Browning machine guns two sizes of ammunition boxes have been developed. The Type
L-1 (Fig. 4) for the .SO cali ber gun holds SO rounds of ammuniti on and the Type L-2 (Fig. S) for
the smaller caliber gun holds 150 rounds of ammuniti on. These ammunition boxes can be mounted
on or removed from the gun as quickly as a Lewis magazine. The ammunition is feel into the gun
by means of a star wheel mounted in the feed opening. Turnincr of the wheel forces ammunition
from the box into the feed pawls of the gun.
No modification of the gun is necessary in using these types of ammunition boxes and their
positi on on the gun in no way interferes with the rai sing of the cover for clearing jams or other
troubles. Counterbalancing springs hold the cover open for working on the gun mechani sm.
EQUIPMENT
Aerial Tow Targets.
Two general types of tow targets have been developed fo r aerial gunnery maneuvers. the type
"A" for airplane gunnery practice and the type "B" for anti-aircraft battery and mach ine gun
practice. These targets are towed by the airplane at various desired altitudes, depending upon the
kind of mi ssion to be performed.
The aerial tow target consists of an elongated cone-shaped sleeve, made of airplane linen or mer­cerized
cotton cloth, with a wire ring in the la rge end or mouth to hold it open for inflation. At
equal distances along the ci rcumference of the ring are secured six shroud lines which terminate in a
loop to which is fastened the tow line. The tow line in turn is attached to the release hook on the
encl of the towing cable.
18 T E C H N I C A L B U L L F T I N N o. 49
The targets are made in two forms. the sleeve shape having both ends open and the streamline
shape having one encl closed, and are painted in contra ti ng colors to make them visible against
various sky effects. The st reamline target rides higher in the air and induces less drag than the
sleeve target.
In launching the target in flight. it is attached to the towing cable and released by a windlass
thru an aperture in the bottom of the airplane. At the moment of launching the airplane is skidded
leeward of the wind to preclude fouling of the target on the tail. The drag of the target pays out
the cable which is controlled and held by a brake on the windlass drum. pon completion of the
firing maneuver. the target is released from the cable by means of a plunger which is allowed to slide
down the cable and unsnap the hook holding the target. As soon as the target is free, the towing
cable is rewound by the windlass.
l\Ianipulation of the towing cable is effected by windlasses, either mechanically or manually
operated, the latter type ( C- 1) being used only in the NBS-1 airplane. The mechanically operated
windlasses. Type C-2 and C-3 for use in the DH-41\II and 0-2 airplanes respectively, a re wind-driven
by a small impeller placed in the propell er slipstream. The impeller drives the windlass thru a re­duction
ratio of 10 to 1 by means of a worm and spiral gear. vVith the mechanically operated wind­less
it requires only three minutes to rewind 2100 feet of cable, whereas the ame operation re­quires
about thirty minutes with the manually operated windlass.
By using wind-driven windlasses it is possible to employ and release several tow targets during
a single flight .
In the aerial gunnery and anti-aircraft maneuvers held during the summer months. four types
of tow ta1-gets were employed with considerable success, particularly from the standpoint of mini­mum
time required for consummation of the maneuver. These types were as fo llows: the Type A-2
streamline ta1-get, 2 ft. in diameter; the Type B-2 streamline target, 3 ft . in diameter; the Type B-4
sleeve target, 3-1 / 2 ft. in diameter by 16 ft. long: and the Type B-4 sleeve target. 4 ft. in diameter
by 18 ft. long. Of these the last named was especially successful in aid ing observers to check de­pression
of anti-aircraft gunfire.
Proposed Heavy Duty Field Service Truck.
A study has been initiated to cover the development of a heavy duty field service truck for
transporting fuel from th e supply base to the airdrome and for servicing airplanes on the field. The
equipment will be mounted on a Class "C.'' 3-1 / 2-ton . six-wheel, pneumatic tire, U . S. Military
chassis.
The proposed truck will can-y 1000 gallons of gasoline. 100 gallons of oil. 100 gallons of water,
a power driven fuel pump capable of del ivering 85 gallons a minlite. an emergency hand-operated
fuel pump of the rotary type. an air comp1-essor and storage tank. a registering meter for measur­ing
fuel , a carbon tetrachloride tank under pressu1-e foi- emergency use in case of fire, and the
necessary hose for handling the vari ous fluid s. l rovi ion will also be made for inflating tires.
The fuel pump. to be driven by a power take-off on the transmission. will be so installed that
fuel may be pumped in four different ways; namely. from the tank car into the truck tank, from
the tank car into storage drums. from the truck tank into the airplane or into storage tanks. or from
the airplane into the truck tank. This apparently complicated arrangement, however, will require
only three valves. a sucti on line and a filling line.
Provision is made for servicing one or more airplanes with fuel at one time. For instance, it
will be possible to service one NBS-1 bombardment airplane with a gasoline capacity of 310 gallons
in four minutes. by employing two men . one on the truck and the other on the airplane. Hence, a
truck with 1000 gallons of gasoline will have suffi cient capacity to service three bombardment and
one pursuit type airplanes, without refilling.
Aircraft Engine Starters.
There has been developed within the present year an electric inertia starter for aircraft engines
of approximately 450 horsepower, whose chief advantage lies in its ability to turn the engine over
at a greater number of revolutions a minute for a brief period of time than the present conventional
type of starter.
AIRCRAFT DEVELOPMENT 19
NEW COMBINATION ELECTRIC AND HAND INERTIA STARTER, TYPE C-5.
The principal operating feature of the inertia starter is the fly-wheel which stores energy thru
acceleration at high speed by an electric motor. The stored energy is uti li zed to crank the engine by
meshing the fl y-wheel with the crankshaft of the engine after the Ay-\\·heel has been accelerated to
the proper speed. Two means have been provided for effecting acceleration. one by a small 12-volt
electric motor and the oth er by a hand-operated crank, either of which may be used. The combined
uni t with 111oto1- and hand crank weighs 40 pounds, and without the motor only 32 pounds.
There are two marked advantages in using the electric inertia sta rter; first. because it require's
onl y one- fifth as much current from the battery as previous types of electric sta rters used in the
service and second, because its use does not impai r the battery ignition for starting, clue to the fact
that at the moment of sta rting no current is taken from the battery. thereby allowing the full
voltage of the battery to be impressed on the ignition coil s. Electric operation requires only th ree
to five seconds to impart the necessary amount of acceleration to the Ay-wheel, whereas hand opera­tion
requi1-es from twenty to fo rty-five seconds to accomplish an acceleration of equal magnitude.
The significant fact is that the sta rter provides a means of hand starting that is nearly as efficient
as elect1-ic starting.
Hanel -operated inertia starter (see illustration) are now avai lable for use on engines of about
200 horsepower. This type of sta rter. accompanied with hand crank, weighs 21 pounds. For com­pari
son, the hand turning gear used in the Air Corps at th e p resent time weighs complete with the
hand crank about 20 pounds. Hence, fo r a slight increase in weight, the hand-operated inertia
starter gives a much greater sta rting capacity.
ECLIPSE HAND.OPERATED INERTIA STARTER.
20 T E C H N I C A L B U L L E T I N N o. 49
I nasmuch as the present electric inertia starter, designed fo r 450-horsepower engines, has demon­strated
its ability to operate engines up to 800 horsepower, a larger unit of g reater capacity is being
developed for engines of 800 horsepower and over. It is expected that the weight of the larger
unit will be very little more than the present one.
For adaptation to all inertia starters there is now under development a so-called ratchet means
of acceleration which will enable the fly-wheel to be accelerated by the pilot without leaving the
cockpit.
HIGH PRESSURE INJECTION SYSTEM OF HEYWOOD AIR ST ARTER.
At p resent there is also under experimentation a high pressure inj ecti on type air starter. This
starter employs a storage tank filled with air at a pressure approx imating 350 pounds per square
inch. An explosive mix ture of air and gasoli ne is distributed to several cylinders of the engine in
proper sequence for firing. The pressure of the air tank is suffici ent to turn the engine unti l an ex­plosion
occurs. The principal problems in this starter lie in findin g a dependable means of getting
the mixture into the engine cylinders and also in determining the extent of maintenance difficulties
under service conditions incident to the use of a multiplicity of high pressure air lin es. nfor­tunately
th is starter is not of a type that can be successfully tested other than by actual installa­tion
in an airplane and under fl ying conditi ons. This disadvantage naturally prolongs the time re­qui
reel for satisfactory test.
Fire Extinguishers for Service Test.
Twenty-five "Ace" fire extinguishers, in one and two quart sizes, have been ordered for service
test from the P hister Manufacturing Company, Cincinnati, Ohio. This extingui sher, which is of
the stored air pressure type as described in Technical Bulletin No. 47, proved quite superior for
AIRCRAFT DEVELOPMENT 21
aircraft use to any type of extinguisher heretofore tested. For installation purposes. the one-quart
size has been installed as a semi-permanent fire extinguisher system in the P\V-9 pursuit airplane and
the two-quart size in the XLB-1 and LB-1 airplanes. It is proposed to equip all LB-1 airplanes in
service with the large size extinguisher.
POWER PLANTS
First Curtiss VG-1550 Engine Completes 50-hour Test.
The first engine on Air Corps Contract 916 for four VG-1550 geared engines has completed
its SO-hour endurance test at the Buffalo Plant of the Curtiss Aeroplane & Motor Company, Inc. In­spection
of the engine upon disassembly after test disclosed no unusual wear. and the engine was
reassembled for calibration and retained at the contractor' plant for further test to determine ef­ficiency
of the reduction gear. As a 1·esult of the test minor changes will be made in the three re­maining
engines on this contract.
CURTISS VG-1 550 AIRCRAFT ENGINE
(525 h . p . a t 2100 r. p . m.)
The model VG-1550 engine is of the 12-cylinder, 60-degree Vee geared type. It has a bore and
stroke of 5-118 by 6-1 / 4 inches respectively, giving a nominal displacement of 1550 cu. in. (actual
di placement 1569.4 cu. in.). The output is rated at 525 h. p. at 2100 r. p. m. of the crank shaft.
which has a gear ratio of 2 :1 to the propeller shaft. The engine is equipped with two Stromberg
NA-Y60 carburetors and one Splitdorf VA-1 magneto with distributors mounted on the end of
the cam shaft idler gear shaft. The magneto is set at an angle to the gear case on a special bracket
and is driven by the upper gear of the upper vertical drive shaft. The reduction gears which drive
through a spring coupling at the propeller shaft gear have stub teeth with 3-1 / 4 inch face.
In general design. arrangement and construction. the VG-1550 engine is similar to the V-1400
engine described in Technical Bulletin No. 46. The weight of the first VG-1550 engine, however.
is about 60 pounds over the original contract weight of 780 pounds for the VG-1400 (geared)
model, due to the increase in bore and the extra thickness of castings and width of reduction gear .
This weight will be reduced in future articles.
Packard New Series 2A Engines Received.
Three of the seven new series 2A-1500 engines being manufactured by the Packard ~Iotor
Car Company under Air Corps Contract 921 have been received. One of these, a di rect-drive
model, will be converted into an inverted engine, using the same carburetor location and arrange-
22 T E C H N I C A L B U L L E T I N N o. 49
ment as provided in the inverted lA-1500 model buil t under Air Corps Contract 8 12, for in stalla­tion
in the Boeing XP-4 pursui t airplane, to replace the model lA engine whi ch gave trouble in the
trials.
Two geared engines have completed calibration and accessory tests at the E ngineering Division,
preparato ry to in stall ation in the new XB-1 and XB-2 bombardment airplanes under construction
by Huff Daland and Curtiss airplane companies respectively.
Changes in Liberty Model V-1410 Air-cooled Engines.
The followin g changes will be incorporated in the eight V-1410 ( inverted) and four VG-1410
(geared) Liberty ai r-cooled engines, being manufactured by the Alli son E ngineering Company
under Ai r Corps Contract 927 :
a. Carburetor mounting Aange will be rai sed 4 inches to improve installation of the engine
in the airplane.
b. Radio shielding will be made of steel in stead of duralumin to insure proper bonding of
all parts necessary to make the shi elding effective.
r:. P rovision for removal or replacement of electric generator when in stalled in airplane will
be made.
d. Scavening oil pumps in each cam shaft housing will be of the triple-gea1-ed type with
suction from each end of the housing to enable scavening in all positions of fli ght.
c. P rovisions will be made for driving a tachometer from the supercha rger shaft as a means
of determini ng whether the latter is operating satisfactorily.
f. The mounting of the elect ric inertia starter will be modified to hold the overall length of
the engine at the minimum.
g. The oil jacket on the rotary induction case will be modified to permit its use either as an
oil jacket or as an exhaust gas jacket.
The first direct-d rive model V-1410 engine is due for delivery early in the next qua rter.
Automatic Mixture Control.
To relieve the pi lot of all responsibility of adj ust ing the fuel mi xture of the aircraft engine to
compensate for changes in altitude during Aight, the automatic mixture control was developed. This
device, operated by changes in atmospheric pressure. consi sts of a removable unit, which is attached
to the carburetor of the engine to maintain constant fuel-air mixture ratio at all altitudes. Follow­ing
its successful application to the Wright H engine in the MB-3A airplane, its use on all pu r­suit
airplanes was believed to be parti cul a rly advantageous for combat or other maneuvers in which
the altitude of the airplane changes rapidly and the pil ot must devote his attention to the control of
the airplane and execution of the maneuver rather than to detail fun ctioning of the engine. \IVith
thi s eud in view modificati ons were made to adapt the unit to the Stromberg carburetor for use on
the Curti ss D-12 engine.
AUTOMATIC M!XTURE CONTROL FOR NA-YSD CARBURETOR.
AIRCRAFT DEVELOPME r T
The automatic mixture control unit proper consists of an evacuated sylphon, a cyli ndrical valve
and a spring which when compressed tends to extend the sylphon and close the valve. The sylphon
being evacuated is sensitive to pressure changes only and if the pressure of the atmosphere surround-
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SCHEMATIC LAYOUT OF AUTOMATIC MIXTURE CONTROL UNIT ON NA-UGA CARBURETOR.
ing it decreases, its resistance to the force of the spring also decreases, causing the valve to partly
close. This valve so regulates the amount of air bleed from the air intake to the float chamber of
the carburetor that as the valve closes less air passes to the Roat chamber. This action increases the
suction above the fu el in the Roat chamber, thus decreasing the fuel Row and prod ucing a leaner
mixture.
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MANUALLY OPERATED MIXTURE CONTROL VALVE.
In case of failure of the automatic mixture control unit or for other reasons that the pilot may
wish to control the mi xture, there is provided on the automatic unit a manually adjusted mixture
control valve that may be operated from the cockpit. The manual control may also be used to
obtain very lean mix tures such as may be desired for operating at crui sing speed on long cross­country
Rights.
24 TE CH N I CAL B UL LET I N N o. 49
Tests of the automatic mixture control unit as applied to the Strombe1-g N A-Y5D carbureto rs
on the Curtiss D-12 engine have been conducted in the altitude chamber at the Bureau of Standards
under direction of the Engineering Division to det~ rm i ne what profile of control valve is best adapted
to these carburetors. Both the control unit and the carbu reto rs have been returned to the Division
recently, where preparations a re being made to fl ight test them.
Nickel-plated Aluminum Fuel Tanks Unsatisfactory.
Laboratory and service tests have shown that nickel-plated aluminum fuel tanks are unsatis fac­tory
in their present state of development, clue to the fact that corrosion takes place more rapidly
than in tanks made of brass, tinned steel or uncoated aluminum. The nickel-plating secured so
fa r is quite uneven and is fi lled with minute pin holes which allow aluminum hydroxide to form
under the coating. causing it to flake off. Corrosion is further accelerated by electrolytic action in­duced
by the potential difference of the two metals in the presence of moisture. As a result the use
of nickel-plated alumi num tanks will be disconti nued until some means have been found to eliminate
th is condition.
Scintilla Magnetos.
As a result of experience gained in over one thousand hours of endurance testing of the Scin­t
illa SB magneto. an orde1- has been placed with the Scintilla Company for a new and decidedly im­proved
model of the double type, to be designated Type SC. T he principal features embodied in
the new type SC magneto. three of which a re being procured fo r test. are its red uced size and pivot­less
breaker mechani sm.
The New Pivotless Type Magneto Contact Breaker.
A new type of magneto contact breaker, known as the pivotless type, is undergoing extensive
bench and engine tests in the laboratory. One pair of breakers, installed in a Splitdorf V A-1 mag­neto,
ha run for a period of 1500 hours at 4200 r. p. m. without replacement of any parts and with
only two adj ustments of the contact separation d uring th is period, the last 700 hours being run
without fu r ther adj ustment. A similar pair of breakers on a Scinti lla SB magneto has run for a
period of 1071 hours at this same speed without a ny adjustment whatever, and the breakers were
still in good condition at the encl of the run. Fol lowing this test, the same magneto was run at
7500 r. p. m. on bench test without missing or chatteri ng. In comparison, the maximum time ob­tained
on the conventional lever type magneto breake1- at 3800 r. p. m. without adjustment is only
100 hours. P ivotless breakers will be used in the new double type Scintil la and Splitclorf magnetos .
•
NEW PIVOTLESS TYPE (Le ft) and CONVENTIONAL LEVER TYPE ( Ri ght) MAGNETO CONTACT BREAKERS.
RESEARCH AND EXPERIMENT
I
RESUME OF ENGINEERING DIYISION
SERIAL REPORTS.
Serial Reports 111ar!?ed 'U.tith an asterisk (*)will be
issu ed by the Chief of Air Corps as "Air
Corps Infor/llation Circu lars."
AIRPLANE SECTION
Serial 2676-Roll, Yaw and Rudder Moments on Douglas C-1 Cargo Airplane.
This report contains results of the wind tunnel test for roll, yaw and rudder moments on a
model of a Douglas C-1 transport airplane equipped with Clark "Y" wings, for the purpo e of
sup1)le111enting data obtained in a previous test of the same ai rplane for liEt, drag and moment, using
both E iffel 385 and Clark "Y' wings.
Serial 2683- Additional Wind Tunnel Data on Huff Daland XLB-1 Airplane.
This report is a continuation of wind tunnel tests on a 1/ 36 scale model of Huff Daland XLB-1
airplane with the thi rd consecutive modification and gives a comparison of aerodynamical charac­teristics
with previous alterations and the relative drag with various combinat ions of bombs carried
under the fuselage.
Serial 2685- Wind Tunnel Test of Proposed Verville-Packard Pursuit Airplane.
This report gives the general aerodynamic characteristics of a proposed Verville-Packard sin­gle
seater pursuit airplane as determined on a 1/ 18 scale model. The design incorporates a tapered
wing biplane airplane constructed about the Packard " 1500" engine.
Serial 2686- Wind Tunnel Test of Model of Boeing PW-9 Pursuit Airplane.
In this report are given the general aerodynamical characteristics of a 1/ 18 scale model of the
Boeing P\IV-9 pursuit airplane, as determined in McCook Field wind tunnel. T he model was tested
for Ii ft, drag and moment, with and without tail surface and chassis.
'~ Serial 2692-Strength of Bent Struts.
This study covers the development of a formula for determining strength of long struts after
an ini tial bending. In E ul er critical loading of a strut. pin jointed at the ends, the form ula is the
same whether the strut is initially straight. eccentrically loaded. or initially bent, thereby expressing
the condition of elastic instability rather than strength. This is, however, the upper limit of the
strength , and generally speaking the strut will br~ak before this limit is reached, not because it be­comes
unstable but because the breaking strength of the outer fiber is reached.
In the application of the form ula, as given in the appendix, it is shown that a chrome molyb­denum
steel tubular strut one inch in diameter by 60 inches long loses nearl y one half its strength
when there is an initial bow of one inch. In comparison the permissable deflection in practical
work, however, is very slight, being in general less than y,i inch in this length.
A nomographic chart for determining acceptability of a bent interplane strut is appended.
26 TECHNICAL BULLETIN o. 49
Serial 2694-The Extended Induction Theory.
In this report is contained a revised and enlarged treatise on the extended induction theory,
originally prepared and presented in briefer form before the International Mathematical Congress
at Toronto. Canada, in 1924. The report deals with the determination of aerodynamics of the wing
cellule as affected by the flow area and its relations to the dimensions of the cellul e, a problem con­fronting
all aeronautical engineers and designers in their basic calculations.
In presenting this theory, certain mathematical 1-elations a re advanced between the principal
dimensions of the cellule and the performance desired of the airplane, particularly the influence
of induced resistance of monoplanes and multiplanes.
Serial 2698-Wind Tunnel Test of Model of Proposed Reconnaissance Airplane.
In this report are given wind tunnel test results on a 1/ 24 scale model of a proposed long dis­tance
reconnaissance airplane as furni shed with two different designs of wings. In general the de­sign
embodies a biplane cellule with 90 per cent of the area in the upper wing. Other features in­clude
a retractable landing gear and a two-engine power plant in tandem arrangement in the
fuselage.
This model was much larger than any heretofore tested in the McCook F ield 5-foot wind
tunnel and was the first model to be tested on the newly installed wire balance and the second model
to be tested under the altered flow conditions of the tunnel, resulting from the removal of the
honeycomb, the addition of a special intake straightener, and the recalibration for reduced tur­bulence,
as discussed on page 35, Technical Bulletin. No. 46 under .. Serial 2636---Recalibration of
McCook Field Wind Tunnel."
Serial 2699-Interference Tests on DH-4B Model and Propeller.
T his report is a continuation of a series of tests for mutual interference and slipstream effect
as conducted in the large wind tunnel at the Massachusetts Institute of Technology, and described in
report "Preliminary Tests of DH-4B Model and Propeller." It contains an account of experi­ments
that have been completed for several angles of attack and the work done on effects of inter­ference
due to stabili zer angle, and the removal of various parts. All results are expressed as curves
of coefficients for various angles of attack and settings of tail surfaces, with and without propeller.
The results herein given are not necessarily considered as final , particularly in regard to pro­peller
torque.
EQUIPMENT SECTION
Serial 2661-Driftmeters for Pursuit Airplanes.
Driftmeters for pursuit airplanes are intended fo r temporary use only in long flights to enable
the pilot to measure the drift ,that is, the hori zontal angle between the heading of the airplane and its
actual path over the ground. For this reason the instrument must be designed to permit its ready
installation or removal without interference with other equipment.
The report deals with the purpose, description and test of an experimental driftmeter, Type
C- 1, developed for pursuit airplanes by the Bausch & Lomb Company, Rochester. N. Y., in accord­ance
with specifications and sketch prepared by the Engineering Division. The instrument con­sists
of a vertical optical system which projects an upright reduced image of the ground upon a
fie ld of vision normal to the pilot's eye. Rotating the reticule by means of a controller fitted with
a pointer and scale shows the amount of cl rift after an observation has been made.
During tests at Selfridge F ield, it was found that the instrument in its present form is unsuit­able
for use in pursuit airplanes, owing chi efly to the inabi lity of holding the image within the fie ld
under the unstable air conditions usually encountered at low altitudes. It is believed that further
tests should be made before a complete redesign of the unit is attempted.
Several views of the instrument and a draft of the preliminary specifications are appended.
RESE RCH A D EXPERIMENT 27
Serial 2664-Test of Herzmark A V-2 Starter for Liberty Engine.
In this report is given a detai led account of the test conducted on the Herzmark A V-2 starter,
designed for the L iberty engine by Dernarreur Herzrnark, Pari s, France. The starter is essentially
of the mixture induction type. It consists of three essential parts; namely, the starter proper, the
distri butor and the air pump. The starter proper contains the storage chambers for air and gasoline,
the fo rmer being supplied by the air pump and the latter by gravity from the fuel system. Two cop­per
tubes conduct the ai r and fuel from their respective chambers in the starter proper to the mix­ture
di stributor which in turn is connected with each cylinder of the engine and timed to assure ad­mission
of the mi xture in proper firing sequence. The mixture is admitted into the cylinders in
atomized form thru special spark plugs and adapters furni shed with the starter, and in this in­stallation
is ignited by an auxilia1-y ignition system such as a hand operated magneto. Only one
start can be accomplished at one charging, the entire operation requiring three to four minutes.
Although the Herzmark starter has demonstrated its ability to start a Liberty 12 engine, its
adoption for service use is not recommended for several reasons. chi ef among which are the fo llow­ing
: the possibili ties of failure thru leakage; the multi plicity of operations required for a start ;
the diffic ulties incident to installat ion and maintenance; and the existence of other satisfacto1-y
sta rters of more compact design whose failure does not in any way interfere with the operation of
the engine.
Serial 2688-Test of Purox Liquid Oxygen Vaporizer.
This test was conducted to determine the practicabi lity of the P urox oxygen vapori zer. which
uses an electrical heating element to vapori ze the liquid oxygen . by measuring the flow of oxygen
obtained from this vaporizer and the amount of current consumed in producing it.
It was shown that the vapori zing unit as a whole is to heavy for its capacity, 5 liters of liquid
oxygen, and that its rate of flow is too low in compa rison with the amount of electri c current used.
In order to produce an adequate gas flow of 20 to 30 liters per minute, the weight of the electrical
system chargeable to the oxygen supply would have to be increased 15 to 20 pounds, a prohibitive
amount for such a vapori zer.
It is bel ieved a vapori zer uni t of a more effi cient type can be built to fit this container.
Serial 2689-lnsulating Material for Liquid Oxygen Vaporizers.
In this investigation tests were carried out to determine the best in sul ating material fo r use be­tween
the ·walls of double wall li quid oxygen vaporize1-s, it being desirable to develop vaporize rs of
both this and the double wall vacuum type.
Three materials were tested: Calorax, a fluffy. finely divided mineral produced in the electric
furnace by the General E lectric Company ; Balsam wool. a fibrous material produced by the Wood
Conversion Company of Cloquet. Minnesota: and Poplox. a popped sodium silicate (water glass)
developed by the General Elect1-ic Company. O f these materi als, Poplox proved to be the best in­sulator,
especially from the standpoints of light weight, ease of production and low cost. Heretofore
Calorax was considered the best in sulating material aside from the vacuum space or ideal air space
free from radiation and convection currents.
A description of the materi als and methods used in determining their relative merits is given
in the report.
Serial 2696-Brandis Octant with Willson Telescope.
This report covers an investigation of the Brandis & Son Type 206 octant equipped with an
artificial horizon, the vVillson bubble telescope, to determine accuracy of readings obtainable with
this in strument in airplane fl ight over land. Compari son is made between the Type 206 octant.
which is a 5-inch ma rine octant of conventional design, and a Brandis & Son 7-inch sextant previ­ously
de cribed in T echnical B ulletin No . 46 under the heading ''Aircra ft Sextant Observations,
Serial 2630." The artificial horizon device did not give consistent readings in fli ght, and the errors
found exceeded the permi ssible limit for an in strument of this type.
28 T ECHN I C L B LLETI No. 49
•:•serial 2697-24-Inch Revolving Incandescent Beacon, Air Corps Type B-3.
T his 1-eport constitutes a manual on the installation, operation and maintenance of the 24-inch
revolving incandescent searchlight beacon. A. C. Type B-3, recommended for use on night airways.
T he beacon is provided with a motor driven revolving mechanism enclosed in the base, a beam ele­vation
adjustment, and an automatic lamp changer. The searchlight dn1111 is fitted with a 24-inch
diameter, 10-inch focal length parabolic reAector of silvered glass, a heat protector. and a door of
clear glass. The lamp changer holds two 32-volt. 1500-watt incande cent lamps, one for running
and th e other fo r spare. Failure of the running lamp automatically lights and throws into focus
the spare lamp, and at the same time closes th e signal lamp ci rcuit on the main switchboard to give
wa rning that replacement of the burned out lamp is necessary.
Several vi ews of the beacon and lamp changing device. together with wiri ng diagram and beam
elevation cha1-t, are appended.
FL YING SECTION
Serial 2678-Performance Test of Huff-Daland AT-2 Airplane.
Results of an official performance test of the Huff-Daland AT-2 tram1ng airplane equipped
with Wright E 180-h. p. low compression engine and a nine-foot duralumin propeller set at 13 de­grees
pitch at 48 inches radius are herein given. T he AT-2 airpla ne is a modification of the Huff­Daland
Dog Ship into a single seater for participation in the pursui t-trai ning competition recently
held at McCook Field.
Serial 2684-Use of Darwin Yaw Meter in Measuring Air Flow.
Small angles of air flow were measured in Aight by means of two Darwin yaw meters con­structed
by the E ngineering Division for use on the Gallaudet monoplane bomber. Each instru­ment
consisted of two pitot tubes mounted together below the wing in the form of a "Y" with an in­cl
uded angle of 120 degrees between the arms. By placing the in strument parallel to the air Aow or
the longitudinal axis of the airplane, any deviation from the original direction was measured by the
pressure difference in the arms. which was indicated on a -tube in the .cockpit.
Views of the installation are included.
Serial 2691-Performance Test of Thomas-Morse X0-6 Airplane.
This is a complete report on the per fo rmance test of the Thomas-Morse X0-6 all metal obser­vation
airplane. equi pped with Liberty engine and adjustable blade duralumin propeller. 10 feet in
diameter. with blades set 18 degrees pitch at 48 inches rad ius.
POWER PLANT SECTION.
Serial 2407-Aviation Engine Descriptions and Performance Curves.
(Revision of Ju ne 10, 1926)
T his report contains authoritative in fo rmation on th e characteristics and perfo rmances of sixty­two
types of aviation engines as compiled from data obtained at the Engineering Division or other
sources under its supervision. The data included in this latest revision a re of parti cular value to
airplane designers.
Serial 2674-Light Oil Tests for Curtiss D-12 Engines.
T he necessity of using lighter oil than that given in the Air Corps Specification 2-23E for start­ing
Curti ss D-12 engines in cold weathe1- led to an in vestigation to determine whether 1obiloil
''Arctic" would affo rd sufficient protection to the engine. Jt was found that this oil is satisfactory
for winter use, provided certain precautions are observed and a change of oil is made after not
more than five hotu- of flying.
As a result of these tests a tentative specification fo r a light oil for winter use in the Curti ss
D-12 engine has been prepared. This calls fo r the addition of Grade 50 oil to the present speci­fication
2-23E oil. F urther experimentation will be conducted, however, to obtain an oil giving less
deterioration with use.
RESEARCH A D EXPERIMENT
Serial 2679-Method of Conducting Acceptance Test of Turbo-Superchargers.
In this report is outlined a standard method of conducting inspection tests of turbo-superchargers
for convenience of Government inspectors and contractors. The discussion covers the definition of
terms. over-speed test, determination of exponent of heat in compression and supercharger inlet
pressure, methods of te t and calcul ation. and general requirements to be met before acceptance.
*Serial 2681-Carburetor Metering Jet Calibration.
Inconsi stencie in Row characteri stics in carburetor metering jets of the same size. together with
the absence of any standardized methods fo r selecting jets of equal Row. led to the present investi­gation
in which a means of calibrating carburetor mete1·ing jets was developed and recommended for
adoption by the Army and Navy air services and carburetor manufacturers.
Experience ha shown that it is impossible to obtain identical fuel Row from several fuel
metering jet dri lled with the same size holes when mounted in the carburetor on the engine.
Obviously the selection of jets had to be made on some apparatus other than the carburetor. The
report deals with the three principal methods and kinds of apparatus used by the Air Corps and the
Stromberg and Zenith carburetor manufacturers, describing in detail the proposed method and de­vice
recommended as standard for adoption.
The proposed standard method involves the measurement of the quantity of Row in unit time
under constant head.
INVESTIGATION OF MATERIALS
Portable •Welding Apparatus on Service Test.
A portable welding outfit. suitable fo r transport by air, has been developed for making emer­gency
repairs in the fi eld. The set weighs 84 pounds without the carrying case, and consists of
PORTABLE WELDING OUTFIT.
standard commercial tanks and welding torches.
T he acetylene tank has a capacity for 6 hours and
50 minutes of operati on, using a No. 2 torch, and
the oxygen tank, 7 hours and 25 minutes using
the same torch. The present temporary carrying
case weights 34 pounds. but this weight will be re­duced
after demonstrations to the service have
been completed.
Airplane Dope with High Gloss Finish.
In view of promising results obtained in ex­perimental
tests. a quantity of high gloss special
pigmented dope, sufficient for fini shing five air­planes.
has been requested for procurement fo r
service te 't. This dope produces a glossy fini sh
similar to varni sh, and eliminates the necessity of
applying varnish to airfoil surfaces for the fini sh­ing
coat.
Rubber Lumber and Rubber Paint.
A new synthetic rnate1·ial. consisting of two
outside plies of fabric with a hard rubber composi­tion
core. is being developed by a large manufac­turer,
under the designation "Rubber Lumber."
Samples of this material have been tested. but no
direct application to airplane structures has been
found. The material is more resistant to mois­ture
than plywood. but it does not have equal
stiffness for the same weight. Its exceeding flexi­bility
constitutes its principal disadvantage.
An investigation has been completed on sam-ples
of paint using a rubber solution as the vehicle.
These paints were found quite resistant to moisture but tended to turn white and check badly upon
exposure to the sun. In their present state of development they are not applicable as a protective
coating for aircraft structures.
NEW BOOKS AND DOCUMENTS
ADDITIONS TO
ENGINEERING DIVISION TECHNICAL FILES
DURING THIRD QUARTER, 1926
INTERNATIONAL AERONAUTICS
Document numbers refer to Engineering Division file reference
Inte rnationa l
Air commerce act o f 192 6. passed by
cong ress and approved by the Pres ident,
May 20, 1926. 13 p.
National defense a ct. July, 19 24. 77
pa~es.
Act to prov ide more e ffectively for nat ional
defense by in c reas ing effic iency of the Air
Corps of the Army of t he United States.
Jun e 3, 1926. 19 p.
Annual report of Chief o f Bureau of A e ro­nautics
to Secretary o.f the N avy for fi scal
yea r s , 1924 and 1925.
Development o f aviation in France. Cat.
Jul y, 19 2 6.
In spection trip to pla nt of Handley-Page,
L td . England. Aug. 9, 1926.
Re view of aeronautics t hro ug hout the
world. In Italian. Notiziario Tecnico No. 5.
May, 1926. 74 p. Jllu s . d iags.
Review of ae ro nautics throughout the
world. In Ital ian. 1926. 76 p. Drawings,
charts . illu s .
Long di stance airplanes a nd their import­ance
in aviation; Alfred Gymnich. Tr. from
Luftfa hrt N o. 9. Ma y 5, 1926. 6 p. lllu s .
Military importa nce of unmanned airp lanes.
June 3, 1926. 2 p.
Digest of s peeches at fifteenth regular
meeting of Wi sse n sc h aftlic h ~ Gesollschaft fur
Lufthart. June 17, 1926. Tr. from Ze it ­schrift
fur Flugtechnik und Motorluft­schitrahrt,
J uly 14, 192 6. Natio na l Ad visory
Committee for Aeronautics. Technical memo­randum
No. 379. Sept. , 1926. 15 p .
Minutes of National S c rew Thread Com­miss
ion meet ing No. 113. Bureau of Stand ­a
rd s . Jun e 28, 1926. 25 p.
Report on ni g ht pursu it prob lems con ­ducted
at L a ngley Fie ld , Mar. 22 -A pr. 22,
1926 ; by Harvey W. Cook. 7 p .
Compe titions, P ersonnel, Records, Etc.
Ame ri can team win s international balloon
race and Gordon Be nn ett trophy, Antwerp,
Belg ium, May 30, 1926. 1 p.
Program f or natio nal air races he ld at
Philadelphia, Pa. Sept. 4-11, 1926. 48 p .
Parachu t e contest to be h eld at national
ai r r aces, Phi lade lp hia, Sept. 4- 11 , 1926.
2 p.
P lans for second Ita lian aerotechnical
week. Ita ly . Aug . 23, 1926. 1 p .
Technical test of new airplanes and air­plane
mode ls . Gliding flight competit ion to
be held at Frankfort an Main. Germany,
Aug. 10 - 20 , 1926. Tr. from Luftfa hrt, Mar.,
19 26. 4 p.
Bulletin of Federation Aero nautique In­ternationale,
June , 1926. 43 p.
A00.3 / 64
A00.3 /65
A00.5 / 9
Unite d S tates
C30.3 / 1
1924-25
Al0 / 17
France
F35/131
D00.12 /223
1 9 26-May
D00.12 / 223
1926-July
D52.l / 183
D 52 .1 / 185
D00.12 /225
D00.12 /203
No. 113
C71. l /25
C71.61 /78
D 52.03 /98
D 52.03 / 97
Al0 / 13
Jtaly
D 52.03 / 96
D00.12 / 178
1926-June
S peed ta ble over kilometer course ; for use
in obtaining miles per hour over any de s ired
co urse. Cat. July, 1926. 3 p.
INSTRUCTION
Creation of school of aeronaut ica l engin eer­ing
in Ita ly. Aug . 10, 1926. 1 p .
in troduct ion to study of advanced mathe ­matics
inv olved in a irplane structural prob­lems
. McCook Fie ld. Mis ce llaneo us report
No. 263. July 23, 1926. llb J;.
Air Corps Eng ineering School.
Course on machine tools. Air Corps En­gi
n eering School. M cCoo k F ie ld. Jul y , 1926.
47 p. Drawing s .
Course on eng ine ove rhau l. Air Corps En­g
ineering Sc hool. McCook F ie ld. July, l 026.
25 p.
Course in metal construct ion. Air Corps
Engineering Schoo l. McCook Fie ld. J uly,
1926. 17 p. Drawings.
AERIAL NAVIGATION
Meteoro logical cond itions along a irways;
by Willi s Ra y Greg g. National Ad v isor y
Committee for Aeronautic s . Report No. 245.
1926. 6 p . Cha r ts .
Use of Noon li g hts by British air ministry
at Croyden. McCook Field. Mis cellaneou::;
r eport No. 267. Sept. 9, 1926. 16 p.
RESEARCH
Industri a l research in the United States;
by Maurice Ho lland . First In ternat io na l Man­a
geme n t Congress, Prague. July, 1924. 70 p.
Report of A eronaut ical Research Commit ­tee
fo r year 1925 - 26. 50 p.
Information on work at Bureau of Sta nd ­ards.
Jul y , ln6. 8 p.
Report of work at Bureau of Standards.
Aug ., 1926 . 9 p.
Report of work at Bureau of Standard s .
Sept., 1926. 10 p .
Forest Produ cts Laboratory progres s re ­por
t for June, 1926.
Forest Products Labo ratory progres s re­port,
Aug., 1926.
F irst experiences with rotat ing la bora tory .
Tr. from Naturwissenscha ft en, May 7. 19 2 6,
Vo l. 16 . National Advisory Committee for
Aeronautics . T echnical memorandum No.
372. Jul y , 1926. 8 p.
Reduction of a ircraft performan ce tests.
Ae ronaut ical Research Committee. Reports
and memoranda No. 9 8 5. June , 19 2 5. 20 p.
c harts .
Oscillat ion of airplane wings due to com­bined
tors ion and bending : by H. Blank and
F . Lieb e r s. Tr. by J. S. N ewell from Z. F . M.
De c . 14 . 1925. R esear ch dept. Memo . No.
761. Technica l Data Section. Mem " rep0d.
No. 253. McCook Field. Apr. 16, 1926. 29
p. Cha rts.
D00.114 / 11
C5 1.l / 25
C53.13 /8
Dl2 / 15
D 52.4 1 / 167
D 52. l 6 / 57
A40 / ll
Dl3.46 / 78
D00.12 / 241
D00.1 2 / 253
D00.12 / 111
T. N. B.
non.12
TNB / 112
D00. 12 / 113
T. N. B.
D00.12 / 99
1926-J une
D00.12 / 99
1926-Aug.
B 60 / 12
D00.12
R. & M. / 9 85
D 52 .33 / 13 l
EW BOOKS AND DOCUMENTS
Lateral stability and directional con trol of
airplanes . Tr. by J. Vanier. T echni cal Data
Memo. r eport No. 186. McCook Fie ld. Se pt.
l, 1926. 98 p. Diags .
Behavior of certain airplan es when con ­t
r o ls are abandoned in s talled fli g ht. Ae ro­nautical
Resea r ch Committee. Re ports and
memoranda No. 1020. Nov., 1925. 9 p.
Step-b y-step calculations upon a symmetric
movements of stalled airplan es. Aeronautical
Research Committee. Reports and me moranda
No. 999. Oct., 1925. 22 p. c harts .
Introduction to study of dynami cs o f rig id
body with specia l r e fe r ence to t he airplane.
McCook Field . Miscella neous r e port No. 253 .
July 23, 1926. 86 p. diags.
Di stribution of pressu re over biplane with
wings of unequal chord and s pan. Ae ro­nautical
Research Committee. Re ports and
memoranda No. 997 . Dec., 1925. 15 p. illus.
cha rts.
Moments in r estr a in ed and continuous
beams, by t he method of co njugate points;
by Jules D. Gedo. From Proceedings of
Ame rican Society of Civil Engin eer s . Aug.,
1926. 11 p. Charts.
Theory of airplane structural members sub­jected
to combined ax ial and non-uniform
transverse loads . University of California.
May 6, 1926. 39 p. d iags.
Lines of constant flow velocity; by C.
Wieselsber ger. In German. Aeronautical
Resear ch In st it ute Vol. 2-No. 3. Tokio Im­perial
Univers ity. June, 1926. 11 p. Charts.
Effect of walls of experimental tank on
res istance of mode l. Ae r onautical Resear ch
Committee. Report and me moranda No.
1010. J an ., 1926. 6 p. charts .
Information r egarding rupture occurring on
monoplanes during flight. McCook Field.
June 30, 1926. 4 p.
Tail planes. F rom L'Aerophile May 1- 15,
1926. National Advisor y Committe for Ae ro ­nautics.
Techni cal memorandum No. 373.
Aug., 1926.
Stress analys is of k eel of RS-1 airs hip ;
by Les lie MacDill. McCook Field . . Aug. 27,
1923. 22 p.
Magnitud e of breathing str esses and e f­fect
of va ryin ~ moment of in ertia of keel on
stresses in se mi-rigid a irship RS-1. 1926. 88
p. Photographs, charts.
Nose battens for RS-1 ai r s hip. A com­parison
of Air Corps method of design with
that proposed by W. W. Pagon . Cat. July,
1926. 8 p. Blueprint .
Pressure di stribution on C-7 airship : by
J. W. Cowley and S. J. DeFra:ice. National
Ad v isory Committee for Ae ronautics. Re­port
No. 225. 1926. 1 p. Charts.
Aerodynamic characteristics of airfoils. Pt.
4. National Advisor y Committee for Ae ro­nautics.
Report No. 244. 1926 . 19 p. Charts.
In vestigat ion of air-flow pattern in wa ke
of aerofoil of finite span . Aeronautical Re­sea
r ch Committee. Reports and memoranda
No. 951. Mar., 1925. 28 p. Illu s .
N. A. C. A. CYR airfoil section; by George
J. Higgi n s . National Advisory Committee for
Ae rona uti cs. June, 1926. 5 p. Chart, diags.
Characteristics of N. A. C. A. M-12 air­foil
section. National Adviso ry Committee
for Aeronauti cs. Technical note No. 243 .
Aug., 1926. 6 p. chart.
Effect of roughness on properties of air­foils
. Tr. from Vorla ufige Mitte ilungen der
Aerodynamisc he n Ve r s u c hsan s talt zu Got­tingen
No. 4, Nov., 1925 . National Ad visor y
Committee f or Ae ronauti cs. T echni ca l memo­ra
ndum No. 375. 4 p. charts, cliags .
Experiments with airfoil from which
boundary layer is r emoved by s uction. Tr.
from Vorlaufige Mitte ilungen der Aerody­namischen
Ve r suchsan s talt zu Gottingen No.
4. Nov., 1920. Natio nal Ad visor y Com­mittee
for Ae ronauti cs. Techni ca l memoran ­dum
No. 374. Aug., 1926. 4 p. Photog raph,
charts.
Boundary layer evacuation. In German; by
J. Acke ret. V. D. I. Ze itschift des Ve r e ines
deutscher lnge ni er e. Aug. 28, 1 926 . 5 p.
Illus. drawings.
Al0.231 / 23
D00.12
R. & M./1020
D00.12
R. & M. / 999
Al0.231 /20
D00.12
R. & M. /997
D52.331 / 135
D52.3 / 2
D00.12 / 184
Vol. 2 -No. 3
D00.12
R. & M. / 1010
D52.1 / 182
D52.327 / 22
D52 .7 I 15
RS-1
D52.7 / 16
RS-1
D52.7 / 14
RS-1
D52.7 / 1
C-7
D52.33 8 / 261
000.12
R. & M. /95 1
D52.338 /255
D52.33 8/257
D52.338/260
D52 .33 8/258
Al0.231 / 24
Investigation of influence of pitch on p e r­forman
ce of air propell er with s lipstream ob­structed;
by B. M. Woods and J . E. Younger .
Univ. of California. Mar. 20, 1926. 26 p.
Illus. charts.
Navy propeller section characte ristics as
u s ed in propeller design . National Advisory
Committee for Aeronautics. Technical note
·No. 244. Aug., 1926. 7 p. charts .
T ests of m etal model propellers in combi­nation
with a model V-7 airplane; by Everett
Park er Les ley. National Advisory Commit-tee
for Aeronautics. Technical notes N o.
245. Aug., 1926. 21 p. Photographs,
charts .
Data concerning Haw a11-m etal propelle r.
In German with translation . Germany. Feb.
16, 1926. 6 p. Photographs.
Test of twe lve-inch Kiefer spehrical pro­pe
ller: by M. A. Smith and E. A. Dichman.
McCook Field. Jan. 2, 1924. 8 p. Photo­graphs
.
Inte ra ction b etween propellers and airplane
s tructures. National Advisory Committee
for Aeronautics. Report No. 235. 1926. 23
p. Illus . charts .
Mea s uring intensity of low currents and
hi g h frequency. In Fre n ch. Cat. Ju ly, 1926.
4 p. Illu s . charts , diags.
Some experim ents on motion of fluids.
Parts I, II, and III. Ae ronau tical Resear ch
Institute . Vol 2- No. 2. T okio Impe rial
Unive r sity. May, 1926. 26 p . Illus.
Gaseous combust ion at medium prej) ­s
ures : Pt. 1. Carbon m onoxide-air explos ions
in a c losed v essel. Pt. II. Methane-air P.'< ­plosi
ons in a closed vessel. Aeronautical Re­search
Committee. Reports and memoranda
No. 998. May. 1925. 25 p . Charts, diags.
Inha lation of oxygen in high altitude fly ­ing.
In French. Bulletin technique No. 35.
June, 1926. 44 p. Diags.
Friction and wear in gear whee ls. In Ger­man.
From V. D. T. July 24, 1926. 5 p.
Illu s . d iags.
AIRCRAFT
( H eav ier- t h a n-Air )
Altitude airplanes. In German and Dutch.
Pamph lets .
De velopment of lig ht and small airplanes;
by G. Lachmann. Tr. from Berichte und
Abhand lungen d er Wissenschaftlichen Gesell­schaft
fur Luftfahrt, July, 1926. National
Advisory Committee for Aeronautics. T ech ­nical
memorandum No. 370. July, 1926. 44
p. Photographs, charts.
Designing seaplane hulls and floats. Tr.
from L' Aeronautique. National Advisory
Committee for Aeronautics. Techni ca l memo­randum
No. 376. 17 p. Photographs, diags .
Recent developments in constru ction of all­meta
l a irplanes; by C. Dorili e r. Tr. from
Berichte und Abhandlungen der Wissen­schaftli
ch en Ge•ellschaft fur Luftfahrt. May,
1926. 23 p. Photographs, chart, drawings .
Vickers-Wibault m eta llic constru ction of
aircraft. Cat. July, 1926. 3 p. Illus.
Characteri st ics of r ecent British a irplanes.
Aug., 1926. 17 p.
Brief description of airplane presented by
Mexican government to Guatemala. Aug. 4,
1926.
A vro
Description of Avro ••Ava" airplane
equipped with two 670 -h. p. Rolls -Royce en­gines.
England. Sept. 3, 1926. 1 p.
Boern er
Boe rner s y s tem high -flying airplane; by
P. Meye r. In German and tr. cat. Sept.,
1926.
B red a
Description of new experim ental Breda
night bombardment land- plane. Italy. Aug.
19, 1926.
C ierva
Description of Ci erva h e li copter. From
The Times, Jun e 23 , 1926. England. 1 p.
lllu s .
31
D52.43 /694
D52.33 8 / 2 5n
D52.43 /693
D52.43 / 6n6
D52.43 / 68n
D52.43 / 692
Dl3.41 / 202
D00. 12 / 184
Vol. 2-No. 2
D00.12
R . & M. /9 n8
D00.12 / 12f>
1926-No. 35
D52.419 / 406
052.1 /3
Boerner
D52.1 / 184
D52.61 /8
D52.l / 18 6
D52.16 /5 6
D52.l / 32
Misc.
British
D52.1 / 2
Misc. Mexico
D52.1 / 16
Avro
D52.l / 2
Boerner
D52.l / 12
Breda
Al0.22 /6
Ci erva
T E C 11 1'i I C A L 13 lJ L L E T I N N o. 49
Data regarding the Autog iro. N ews paper
c lippings and photog raphs of Cie rva Auto­g
iro. Eng land. Aug . 24 , 1926. 10 p . P ho t o­graphs
.
Curtiss
Photog raph s of Curtiss Hawk Navy FC6-4
equipped with Wasp eng in e .
Enots
Catalogs of Enots a irp lan e components
man ufac t u r ed by B enton & Ston e, Ltd. Eng ­land.
July 23, 1926. lllus .
Farman
Al0.2 / 33
D5 2. l / 227
Curtiss
D52.39 / 226
Description of Fa r man F. 170 equ ipped D 52. l / 47
with 500 -h. p. Farman engine . Tr. f rom Farman
L es Ailes, Apr. 8, 192 6. National Adv isory
Committee for Aeronautics . Airc raft c ir-cular
No. 12. Aug., 192 6. 5 p. Phot ographs ,
drawings .
Farman comme rcial airp lane "Jabiru." Tr. D52.1 / 48
f rom Socie te des Avions . National Advisory Farman
Committee for Aeronautics . A ircraft cir-c
u lar No. 15. Sep t ., 19 2 6. 6 p. P h oto-g
raphs, dra wings .
Focke-Wulf
Brief d escription of Focke-Wulf Al6D com- D 5 2. l / 4
me ri ca l airp la n e . June 1, 1926. 1 p. Focke-Wulf
H einke!
Description of Heink e ! a irp lan e DH- 39 for D52 . l / 7
carrymg news pape rs . F rom Flugspo rt , May Heinkel
1, 192 6. National Advis ory Committee for
Ae ronauti cs . A ircraft c irc u lar No. 13. Aug .,
192 6. 9 p. Photog raphs.
Ka tzens t ein
Description of ne w mo noplane S chwalbe D52.l / 1
KL- 1 of Raab Katzen s tein Company. June Katze ns t ein
3, 19 2ti. 3 p.
Macchi
Characteristics and expect ed pe rformance
of Macchi 37 seaplan e . lta ly . June 4, 1926.
1 p.
Sikorsky
D52 .6 / 13
Mac c hi
General d escription of Si k ors ky S -35 D52.l / 5
t r a n s -At lan t ic ai rplane . Se pt. 3 , 1926. 1 p . Siko r s k y
Sperry
Test of Sperry Messenger airplan e equ ipped D52.1 / 4
with variable camber wing; by Otto E . Sperry
Kirchne r. S ept. 2 , 19 2 6. 5 p. Drawings,
phot og raphs.
Ude t
Description of Udet U-11 Konde r.. June D5 2. l / 3
3. 192 6. 3 p. Udet
Wibault
De s c ription of Wibault a ll-m e ta l two- seater D52.l / 10
monoplane, type 8C2; by J. S e rry e r . Na- Wibault
tiona l Advisory Commit tee for Aeronautics .
Aircraft circular No. 9. Jun e , 1 9 2 6. 6 p.
Illu s . d ia gs.
ARMAMENT
Description of n e w Be lg ian bomb and D72.3l / 169
bo mb-dropping de vi ce. Be lg ium. Ju ly 8 .
192 6. 2 p.
Informat ion on Type Ill parachute fla re Dl3.4 5/3
candl e. McCook Field. July 29, 1 926. 2 p.
EQUIPMENT
Equipment tables for N a t ional Guard D00 / 21
medi cal de tachme nt. Cat. Aug ., 1 926 . 1 p.
Standard hos e conn e c t ions for welding and D 52.416 / 27
cutting torches . Nat ional Sc rew Thread
Commis sion. Bureau of Standards . June 30,
1926. 1 p . Drawings.
In s tru c t ions on Gourclou-Lesseur oxygen Dll.331 / 65
apparatus . In Fre n ch. 19 23. 7 p. lllu s .
Catalog on Neg r e tti & Zam b r a t h er- D l 3.3 / 26
momete rs for aircraft. Cat. Aug ., 1926. 23 Thermome t e rs
p . lllu s .
P reparation of airplane for radi o a nd in ­s
ta llat ion of serv ice type radio sets th e re in ;
by L eRoy M. Wolfe and Ford S t udybake r .
McCook Fie ld. Mis ce llan eous re po rt No.
249 . Jan. 12, 192 6. 117 p. lllus . dra wings.
Information on E c lipse e lectri c s tarter. In
Fren ch. From La Conque te de l'a ir, Aug . l,
1926. 2 p . illus .
Dl 3.4 1 / 20 3
D 52.41 5 / 42
De s cription of hydraulic dynamome ter, and Dl 3 .6 / 70
t he H eenan-Fe ll air bra ke dynamome t e rs .
J a n ., 1926. 39 p. P h otog raph s, drawings.
Inves t igation of ai rplane tire inn er line rs D52 .54 / 9
to de t ermin e sa t isfa ctory mean s of o vercom-ing
tire tro uble due to pun c tures . McCook
F ie ld . Aug . 3, 1926. 3 p .
Duralumin disc 2 8x4 a irp lan e whee l. Mc­Cook
Fie ld . Aug . 5, 1926. 2 p.
Static tes t o f Sauzedcle a irplane wheel; by
Charles J. Clear y . McCook Fie ld. July 24 ,
1926. 2 p.
FUELS AND LUBRICANTS
An t i-knock prope rties of "Smacko ve r"
g asoline produ ced by c rackin g ; by Gustav
Eglo ff and Jacque C. Morre ll. Un ive r sal Oil
Products Co. Cat. July, 1926. 3 p.
Topping and c ra c king of "P a nhandle"
crude o il; by Gustav E g loff and Jaco ue C.
Morre ll. Universal Oi l Produc t s Co. Aug . 4,
1926.
Su rfu ric a c id abs orpt ion and iodin e values
of various petroleum products and c racked
d is t illates obta in ed t h e refrom; by Jacque C.
MorreU and Gustav E g loff. Uni versa l OiJ
Products Co. Dec., 1925. 5 p. Cha r t s .
l nves tigatio n of combus t ion
mixtures : by Andre Pig not.
Bu lletin No. 3 4. May, 1 926.
diags. , charts .
o f carbureted
ln Fre nc!l .
53 p. lll u s .,
Co ld storage and re fri J:rerati on mac hine ry
lubri cati on. The Texas Company . July,
1926. 12 p . Illus. dia g s .
MATERIALS.
D 52.5 6 / 39
D5 2. 56 / 38
Dll.31 / 96
Dl 1. 2 1 / 105
Dil.2 1 / 102
D00. 12 /126
1926 -No. 34
D5 2 .4 12 / 34
Effect of corros ion on stren g th o f we ld ed D52.3 l 3 / 31
jo ints in steel tubing; by D. M. Warne r. Mc-
Cook F ie ld. Ju ly 12, 1926. 5 p . Dra wings.
Effect of g roo ves, t hread s and corros ion 01 0.l / 145
upon fati g ue of m etals; by Richard R. Moore.
McCook Fie ld. Cat. July, 1 9 2 6. 16 p.
Charts, drawings.
Test s of rubber paints applied to a luminum Dl 1.22 / 3 I
and mag nesium alloys. McCook Fie ld . S ept.
7 , 192 6. 6 p .
Exten s ion of fin e pi tch sc r ew thread D00.12 / 252
seri es. National S crew T hread Commis sion.
Bur eau of Sta ndards. July 8, 1926. 9 p.
Notes on joints and jo ining mate rials . Dl i.4 / 18
Coo pe rs' Mec hani ca l Join ts, L t d. Jun e 2 3,
1926. 5 p.
T es t s of se ve ral b earing mate ria ls lubri- DI0.1 / 147
cated by g a s o line; by W. F. Joachim and
Harold W. Case. Natio nal Ad v is ory Como-mittee
for Ae ronautics . Techni cal note No .
241. July, 1926 . 19 p. Charts, drawin g .
Fabric
Specification for 1 8 -ounce cotton ca n vas D00.1 5 / 16
for use in cons truction of hang ars . B rit is h Misc.
s tandard s pec ifi cations f or airc ra ft materia ls
and compone nts. May, 19 26. F . 37.
Specifi ca t ion for flax t ent duck for use in D00 .15/16
con s tru c t ion o f li g ht t e nts. Brit ish standard
s pec ifi cation s for airc raft materia ls and com-pon
ents . May , 1926. F .39.
Me ta ls
Res ults of tes t s on aluminum all oy samples DJ 0. 13 / 2 42
by The St anley P. R ockwe ll Co . Volcrit
method of h eat- t r eatment by th e Rock e ll di-latom
et e r . Ju ly 8, 1 926 . 14 p . Photo-g
raphs, charts .
Prope rties o f some sand- cast al uminum- D 10. 13 / 24 5
mag nesium s ili c ide alloys. McCook Fie ld.
Ca t. Aug. , 1926. 13 p. Photog raphs, c harts .
Embrittlem e n t of duralumin. R eport for Dl0.13 / 24 3
June, 1926. Bureau of Standards . Ju ly 10,
1926. 29 p .
l
I
{
N E W B 0 0 K S A N D D 0 CU I\f E N T S
Investigation on embrittlement of dura - D 10.13 /249
lumin. Bureau of Standards. Report No. 14.
Sept. 9 , 1926. 16 p .
Letter to Bureau of Ae r onaut ics in wh ich Dl0.13 /2 47
a rticle on corros ion of dura lumin is c riti c ised.
Bureau of Standards. Aug. 27, 1926. 5 p.
Progress report on mic ro- structure of Dl 0.13/248
duralumin . Bureau of Standards . Report
No. 13. Cat. Sept., 1926. 49 p. Photo-g
raph s.
Examination of Major metal. Bureau of Dl 0 .13 /244
Standards . July 24, 1926. 4 p.
Some characteristics of quenching curves D 10.11/14 2
in steel ; by H . J. Fre n ch and 0. Z. Klopsch.
Bureau of Standa rd s . Techn o logic paper N o.
3 13. Mar. 25. 1926. 20 p. Charts.
Dosage of phosphorus in products of fer ­rous
metalJurgy; by R. Caillol. In Fre nch.
Bulletin techn iq ue N o. 33 . Apr., 1925. 40 p.
D00.12 / 126
1926- No. 35
Metallographic etc hing r eagents, Part Ill. Dl0 .11 / 107
For alloy steels. Bureau of Stan da rds. Scien-t
ific paper No. 51 . Dec. 11, 1926. 40 p.
Illus.
Pure z in c at normal a nd e levated tempera- Dl O. l / 149
tures: by J ohn R. Freeman, Jr., and othe rs.
Pt. 1.-Some ph ys ical properties; P t . 2.-
Crysta l stru cture. Bureau of Standards.
Scie n t ific pape rs No. 522 . Apr. 3, 1926. 34
p. Drawings, c ha rts, illus.
Special alloys for super c harger turbine D 10. l / 14 6
buckets; by Frank T. Sisco. McCook Field .
July 8, 1926. 3 p . Photographs.
Rubber
Comparison of rub::, er lumber with wood.
McCook Fie ld. Aug . 23, 1926. 3 p.
Wood
Cause and detection of brashness in wood.
Part IL Commercial white oak. Forest Pro ­ducts
La borato r y. Project L -20 - 5 . July 7,
1926. 55 p . Photograph s, c harts.
D24.4 / 15
Dll.1 /33
Cause and detection o f bras hness in wood. Dll.1 / 339
Part IV. Effect of high temperatu res on
failure in Si t ka spruce broken in be nding, to-gether
with informat ion on e ffect of heat on
certain phys ica l and mechanical p rope rt ies of
wood. Forest Products Laboratory . Fourth
progress report on project L-20- 5. June 12,
1926. 32 p. Photograph s, draw ings, charts.
Toug hness tests of a irplane woods-Do ug - Dl 1.1 / 336
las fir , Coast type, by L . F. Luxfo rd. Forest
Products La b o rator y . P roject L-233-13.
June 10, 192 6. 26 p. Photographs, charts .
In spect ion of Curtiss Aeroplane & Motor DI 1.1 / 337
Company and Consolidated Airc raft Com-pany,
Buffalo, N. Y. May 27, 2 , 1926, for
the purpose of making a survey or seasonin ;
and storage of ai rc raft woods at t hese plant::; ;
by Ro lf Thelen. Forest Products La borato r y.
June 19, 1926. 7 p.
Bearing strength of bolts in spruce. M. I. Dl 1.1 / 340
T. June 1, 1926. 19 p.
Manufacture 0f casein wat e r-res is t ant ply - Dl 1.1 /335
wood; by Don Brouse. Forest Products La -
bor atory. Project L-2 25 -1 3. July 17, 1926.
25 p. Charts .
Tests, Ana lyses, Etc.
Static load deflation data on compress ion
disc s hock absorbers. McCook F ie ld. Sept.
14, 1926. 3 p .
Endura nce test of t ires; by W. L. Holt and
P. L. Worme ly. Bureau of Standa rd s. T ech ­nologi
c papers No. 318. May 25, 1926. 6 p.
Illus. drawings, cha rts.
Fa il ure of SKF special ro ll er bearings . Mc­Cook
Field. July 29, 1926 . 2 p. Photo­g
raphs .
Failure of Curt iss D-12 e ng ine pistons: by
Alfred J. Lyon. McCook Field. July 2, 1926.
2 p. Photog raphs .
In vestig a tion o f casting defects in Curt iss
D-12 pistons. McCook Fie ld. Aug . 17, 1926.
2 p. Photographs.
Failure of o il tube in Curt iss D-12 e ng ine .
McCook Field. Aug. 6, 1926. 3 p . Photo­g
raphs .
Failure of crankshaft N o. 301 fr om Curtiss
V-1400 e ngine; Frank T. Si sco. McCook
Field . July 20, 1926. 9 p. Photogra ph s.
D52.55 / 39
D52.54/10
D52.4 19 /405
D52.419 /400
D 52.4 19 /408
D52.41 / 40
Curtiss
D 52.4 t 9/402
Non-d estruct ive testing of wire hoisting
rope by magnetic analys is; by R. L . Sanfo rd.
Bureau of St anda rds. T echnolog ic No. 315.
Apr. 16, 1926 . 2 1 p. Diags. Illu s., charts.
T est o f no-bl u r on g lass; by G. P . Young,
McCook Field. Sept. 16, 1926. 1 p.
PHOTORAPHY.
Aerial p hotographs; by J ohn P . O'Callag­han:
how they are made and what they a re
used for. From Camera Craft, July-Aug.,
1926 . 10 p. Illus.
Rea ct ion in space and its appl ication to
aerial photograph y: by G. T. McCaw. Cat.
July, 1926. 35 p. Diag .
POWER PLANTS
Improving performance o f compress ion­ign
ition e ng ine by direct ing flow of inlet air:
by Carlton Kempe r. National Advisory Com­mittee
f o r A e ronautics. Technica l note N o.
242. July, 1926. 9 p. Photographs, diags.,
chart .
On knoc kin g o f gasolin e engines. Tr. from
De r Motorwagon, Nov. 20 , 1925, and Jan. 20 ,
May 10, June 20, 192 6. National Advisory
Committee for A eronau t ics. Tec hnical memo ­randum
No. 371. July, 1926. 40 p. Charts.
Gas starter system for a irc raft e ng in es .
A ir publication No. 11 81. Air Minis try . Apr ..
1926. 46 p. Illus. drawings .
Anzani
Facts and details of Anzani air-cooled
radia l a ircraft e ng ine . Cat. Sept .. 1926 . 2 p.
Drawings.
Boerner
Expert opinion
Boerne r syst em.
Cat. Sept., 192 6.
on explosion turbin e of the
In Dutch with t rans lat ion .
6 p.
Approals
In Dutch.
pamph lets.
on Boerner explos ion turbines.
Cat. Se pt., 192 6. 11 p. and 2
Drawings.
Breitfeld-Dan ek
Description of 500- h. p. Bre it f eld-Danek
s upe rcom press ion e ng in e for hi g h altitudes,
develo ping its full power up to 3,000 mete rs .
Cat. Aug., 192 6. 13 p.
Curtiss
Standard fifty -hour e ndurance test of
Curtiss, model VG-15 50, 525 -h. p. aircraft
e n g ine at 2100 r . p. m. ; by M. C. Fox. Curtiss
Ae roplane & Motor Co., Tn c. 29 p. Photo­g
raph s, c harts.
Diesel
Description or all Di esel engin es. In Ger­man.
2 parts. 192 4-1 926. Illu s .
Large Diesel e ng ines and their lubrication.
Jun e, 192 6. 12 p. Illus . drawings.
Fiat
Brie f information on new 6 cylinder Fiat
e n g in e. Italy. J u ly 28, 1926. 1 p.
Na pier
Handbook on Napier Lion, Se ria l 11 B aero
e ng in e. Air Ministry. Air publ icat ion N o.
882. Ed. 2. Mar., 192 6.
P ackard
Fuel cons umpt ion st udies and endurance
test of Packard E n g ine. Packard Motor Car
Co. July 30, 19 26. 16 p. Photogr a phs,
c harts, drawing.
Sa l ms on
Gene ral catalog of Salm son a ir-cooled e n ­g
ines, g iving history and c haracteri stics. In
French. France. 39 p. Ill us. charts .
Wrig ht
Chart s howing performance characteri stics
of Wrig ht J -5 e ng in e . Wrig ht A e ronautica l
Corp. July 29 , 1926.
Pamphlet on Wright Mor ehouse 25 -30 h.
p. engine. Cat., Se pt., 1926. 5 p. drawings.
33
DlO / 232
DlO /2 33
A30.2 / 48
A30.2 /47
D52.4 l / 168
D52.4 1 / 170
D52.415/41
D 52 .4 l / 9
An zani
D 52.4 1 / l
Boerne r
D 52.4 1 / 2
Boerner
D 52.41 /5
Breitfeld ­Danek
D52.4 1 / 41
Curtiss
D 52 .4 l / 11
Diesel
D 52.4 12 / 17
D52 .41 /40
Fiat
D52.41 /9
Napie r-Ed.
D52.4 l /4 0
Packard
D52. 41 / 19
Salm son
D52. 41 /50
Wright
52.41 /53
Wright
34 T E C H N I C A L B U L L E T I N N o. 49
ACCESSIONS TO ENGINEERING DIVISION
LIBRARY.
Aerostatics; by E. P . Warner.
Airc raft and Commerce in War; by J. M.
Sp3 ig h t, L ongmans. 1926. 111 p.
· Aircraft Power Plants; by E. T. Jon es and
othe rs .
Ai rmen and Aircraft: an introdu ction to
aeronautics. By H. H. Arno ld. Ronald. 192 6.
216 p. illus.
Airplane Design, by A. S. Niles. McCook
Field. 192 6. 495 p. Diags.
A. L. R . Cu mulat ive Index-Digest Vol.
40-42.
American Law Reports-Annotated. En-g
ineering Divis ion. Library has Vol. 42.
192 6.
Annual Tables of Constants and Numerical
Data; chemical, ph ysical and technological.
Vol. 5, Pt. II.
Applied Elasticity; by S. T im os henko and
J. M. Lessell s.
Corrosion; by F. M. Speller.
Effect of Tempera tu re upon Prop e rt i e~ o"
Meta I; by American Society of Mechanical
E•1....,.heers and Ame rican Society of Testing
Mater ial.
629 .141
W24
629.13
Sp 1 air
629.183
J71
629.13
Ar65
639.18
N59
345.4
C73a
345.4
AM3
530.8
A7
62 0.1123
T4 8
62 9 .11
Sp3
669
Am3
Free and Captive Balloons ; by Ralph Haz­litt
Upson and C. de F . Chandle r. Ronald
Pr. 1926. 331 p . Illus. diags.
Handbook of Non-ferrous Metallurgy. Mc­Graw-
Hill. 1926. 2 v . Ed. 1. Illus . diags.
Hig her Mechanics. by Horace Lamb.
Man and W eather; by Alexander McAdie.
Harvard Univ. Pr. 1926. 99 p. Illus.
Methods of Meas uring Temperatures. by
Ezer Griffi t h s . Griffi n. Ed. 2. 1925. 203
p. Ill us. diags.
Principles of Metallurgy of Ferrous
Metals; by Leon Cammen.
Radio Telegraphy and Telephony; by S. S.
Robison .
Septune Congrein ternational de legis lat ion
a rienne; by Comite J uridique International de
L'Aviation.
T extile Blue Book, 1926; by Davidson.
Translated abstracts of Techniche Berichte.
1917. Air Ministry. 2 v. 1925. 129 p. Diags.
Treatise on Ordinary and Partial Differen ­t
ial Equations: by William Woolsey John son.
Wiley. 368 p.
Treat ise on We ig hing Mach ines; by G. A.
Owen.
629.15
Up7
669
L61h
531
L16
55 1.5
Mil ma
536.52
G875
669.1
Cl5
621.384
R 56
341.1
C73
677
D29
62n.l42
T 23
517.38
J o63
530.8
Ow25