Technical bulletin no. 36

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AIR SERVICE INFOR
VOLUME V
(AVIATION AND AEROST A TION)
BY DIRECTION OF CHIEF OF AIR SERVICE
SEPTEMBER, OCTOBER, 1923
TECHNICAL BULJLETIN
No. 36
NUMBER 429
DEVELOPMENT OF MILITARY AIRCRAFT MATERIAL FOR UNITED STATES
AIR SERVICE UNDER SUPERVISlON OF ENGINEERING DIVISION.
PUBLISHED BY
Ralph Brown Draughon
LIBRARY
MAY 102013
Non•Oepoitory
Auburn University
ENGINEERING DIVISION, AIR SERVICE
McCOOK FIELD, DAYTON, OHIO
1923
McCook Field-11 -8- 23-IM
CONFIDENTIAL
The information contained herein is confidential and therefore
must not be republished, either in whole or in part, without
express permission of the Chief of Air Service, U. S. Army.
CONTENTS
AIRCRAFT DEVELOPMENT
AIRPLANES
Proposed "Around-the-World" Flight-Douglas World Cruiser (Views)...................... 5
Weig:ht-carrying Tests of NBL-1 (Barling) ................. ....................... ................................ 7
Proposed Changes on NBS-l's-New GA-1 Chassis and NaceJle-Remodeling
DH-4's into DH-4M and DH-4M-l's-........................................................................ 8
Wing Flutter in Fokker PW-5-Huff-Daland TW-5C (Modified Petrel) .... ................ 10
New Thomas-Morse Training-Comparison Wings for Messenger............................... 11
Chassis Failures on SE-5A Service Airplanes .......... .. ............................ ........................ 12
AIRSHIPS AND BALLOONS.
Construction Progress on RS-1 ...... ................................................ ........... ........................... 12
New Training Airships of the TA and TC Class................... ............. ................................ 13
Barrage Balloon and French Type Winch--Balloon Cabinet-Goodrich 20-inch
Gas Valve- Tractive Tests of Highly Mobile Winch .................................... , ........... 14
Engineering Division Balloon Basket Parachute Release (Illustration) .................. 14
ARMAMENT.
British Course-setting Bomb Sights ················· ········· ·················-······································· 15
New Engineering Division Gun Sight, Type X-9 (illustrations).......... .......................... 16
Test of Bomb Rack, Type B-3 (Modified Mark XVI)- Mark I Gun Camera............... 17
New Engineering Division Parachute Flare Rack and Release Handle, Type M-2
(Illustrations) .......... ..... .................... ..................................... ... .......... ............ 17
POWER PLANTS
Tests of Br'itish Engines-Liberty 8 and 12-Volt Ignition Systems (Diagram) ........ 20
New Packard Engine, Model lA-2500- Production of Bellows Fuel Pumps................ 21
RESEARCH AND EXPERIMENT.
RESUME' OF ENGINEERING DIVISION SERIAL REPORTS.
Analysis and Design of R-3 Fuselage--Characteristics of Sperry Venturi and
Calibration of Orifices foii Same- Test of Longren Fiber Fuselage...................... 22
Test of Loening PW-2 Wing-Pyrotechnics for DH-4B Airplanes-Bomb Release
HandJe "L-4"- Machine Gun Synchronizers, Type'.3 C-2 and C-3.............. ........ .. 23
Synchronizer "C-7"-Bomb Release, Handle "L-5"~Gun Sight "X-6"-Installation
of N'ight Flying Equipment on MB-3A, JN-6HB, and NBS-1- Drag Char­acteristics
in Free Flight ... ·......................................... ..................................................... 24
Investigation of "Z-D" Process-Organic Coating for Duralumin-Heat Treat-ment
of Aluminum-Copper Alloys ..................... ....... ................................................... 25
"Flash-over" Altitudes of Spark Plugs-Test Reports of Foreign-built Engines,
LeRhone "Rm," Bristol "Jupiter," and Siddeley "Ja~ar"....................................... 26
INVESTIGATION OF MATERIALS.
Babbitting Directly on 'Steel-Vulcan Rubberized Fabric............................................... 26
Cracks in Welded Steel Struts-Aluminum Alloys for Large Castings-Value of
Specifications in Purchase of Bronze .......... .. ... ....................... ..................................... 27
Frontier Aluminum Bronze--Sediment in Fuel Strainer (Smith-Richter Flight)-
Paravan Coating-Specification for Waxed Linen Thread .................................... 28
Turner Shock Absorber Ring (Illustration) ................... - ............................. ........ .............. 29
NEW BOOKS AND DOCUMENTS.
Documents Added to Engineering Division Reference Files............. .. ............................ 30
4 T E C H N I C A L B U L L E T I N N o. 36
AIR SERVICE WORLD CRUISER- DOUGLAS D-WC
(Model 1923 Liberty " 12" Engine )
AIRCRAFT DEVELOPMENT
ON ENGINEERING DIVISION PROGRAM
AIRPLANES
Proposed "Around-the-World" Flight.
For some time past, the Air Service has been contemplating an "Around-the-World" airplane
flight. The possibilities of successfully accomplishing such a flight have been studied from many
angles with the result that the project has been finally approYed by the Chief of Air Service.
Active preparations for the proposed flight were instituted early in January, 1923, when the
Engineering Division which had been charged with the selection and procurement of practically
the entire flying equipment in connection with the flight undertook an investigation to determine
what types of ai rcraft were best adapted for the purpose.
In this investigation, three available types of airplanes were considered-the F okker F-5, a large
transport similar to the Air Service T-2 but which is easily convertible into either a monoplane for
land use or -into a biplane with pontoons for water use; the new T-3 transport, a passenger-carrying
biplane under construction for the Service by the L -\tV-F Engineering Company; and the Doug­las
DT-2 torpedo carrier, a biplane with which the Navy has been quite successful-with the re­sult
that it was decided to use an airplane of the biplane type that would be powered by a special
Liberty "12" engine, equipped with convertible undercarriage for use on land or sea, and capable
of carrying a fuel supply sufficient for a flight of 2000 miles without replenishment. After a gen­eral
consideration of all the requirements for the flight and the adaptability and availability of the
various designs, the Engineering Division finally concluded that a modification of the Douglas DT-2
design into a type to be known as the Douglas W orld Crui ser, D-WC, would in all probability ful­fill
the desired purpose.
Coincidental with the engineering phases of the proposed world flight, two Air Service officers
were sent abroad on pathfinding expeditions for the purpose of selecting the route, locating landing
field s, establi shing supply bases,. and obtaining other per tinent information. One officer starting
from McCook Field traveled eastward over the Atl antic route thru eastern Canada, Greenland ,
Iceland, Faroe I slands, E ngland, France, Italy and the other starting from P hilippine Islands
travelled over the Pacific route thru China, Japan, Kamchatka, Aleutian I slands, Alaska and thence
to United States. From the data thus obtained, it will be possible to select a definite route from
the several tentative ones under consideration.
Several months prior to the world flight which is scheduled to take place about June 1, 1924,
the personnel is to be chosen and sent to McCook Field fo r special training that wi ll include an in­tensified
course in navigation, meteorology, and kindred subj ects, actual flights with the world
crui ser on long cross-country trips and practical experience in the use of the new inductor compass,
the Engineering Division's aerial sextant, flight indicator, ·and other in struments.
Douglas World Cruiser "D-WC."
The fir st of the World Crui sers, which has been designated the "Douglas D-WC," was built
by the Douglas Company of Santa Monica, California, in about 45 clays from the placing of the con­tract
in July, 1923, and was flown to McCook Field .in October for extensive performance tests.
Only one experimental airplane was purchased at fir st in order that such changes or improvements
that were found expedient could be incorporated in the four additional airplanes which are to be
furn ished on subsequent contract.
Altho the Air Service World Cruise airplane wliich is shown on the foregoing page resembles
the Navy DT-2 torpedo 'plane in general design, it presents a somewhat improved appearance due
to refin ements in streamline and incorporates other differentiating features such as a greatly in­creased
fuel capacity, larger pontoons and steel tubular construction in the tail section of the fuselage .
•
6 TE CH N I CAL B U 1, LET I N N o. 36
The design as a whole is conventio11al but it possesses excellent accessibility from a mainten­ance
standpoint, an important prerequisite for a flight of this nature. The principal structural fea­tures
are its folding wings, sectional fuselage, arrangern:ent of large fuel load. interchangeable un­dercarriage
and hoi sting device for handling airplane on shipboard.
The USA-27 airfoil section is employed for the wings which form a biplane structure external­ly
braced by single interplane wooden struts and streamline wires. The square-tipped wings are of
conventional wood and fabric construction built in sections for convenience of replacement or hand­ling,
the upper consisting of two outer panels carrying the ailerons and a center section for the grav­ity
fuel tank. The lower wing has two outer panels hinged to the wing butts or stubs that are
welded to the fuselage structure to form a rigid support for landing and taxying loads and to
house two of the main fuel tanks. Numerous false ribs in place of the usual plywood construc­tion
maintain the contour of the nose portion. Jury struts are supplied for holding the outer panels
rigid when folded back parallel with fuselage.
Accessibility is carried out in the design of the fuselage which is a steel tubular structure built
in three sections, namely,-nose or engine section, mid or cockpit section , and the tail section, the
rear portion being detachable by removing four bolts. Interior bracing is attained by stiffening
gussets, tubular cross members and tie rods attached to flanged wire pulls welded into the longe­ron
tubing. 11here is no bracing in the plane of the upper longerons in the cockpit section, rigidity
being secured by heavy tank supports and other members below pilot's seat. The main fuel tanks.
three in all, can be removed thru either top or bottom of fuselage without interference from wings
or chassis. The aluminum cowling is quickly detachable in convenient-sized sections as far back
as rear coc1.1)it.
The unbalanced tail surfaces are of conventional construction employing a double cambered
airfoil of medium thickness. The rudder is connected to the tail skid making the latter steerable.
A stabilizer adjustment is provided in the pilot's cockpit. A Dep control is provided for pilot and
the usual stick control for navigator.
The undercarriage is convertible for land or water use. The land undercarriage is a wide tread ,
axleless type of gear with welded . V struts attached under each lower wing butt and an articulated
steerable tail skid. The chassis is equipped with 36 by 8 inch-wheels having a trea.d of 11 ft. 3 in.
The rubber cord shock absorber is not detachable but can be rewound quite easily when in place.
The water undercarriage which replaces the landing gear consists of twin pontoons of stout con­struction.
These have a reserve displacement of about 85 per cent as based upon maximum weight
as seaplane and are secured to the superstructure by 'the latest improved method of bracing.
The po,ver plant to be employed on the World Cruise airplaryes will consist of a special 1923
model Liberty "12" engine fitted with latest improvements such as stub tooth gear trains, reen­forced
cylinder-s, new type C fuel pumps, etc., and using a standard 8-volt Delco ignition system.
The fuel supply consisting of 600 gallons of gasoline js carried in six tanks as follows: One
60-gallon gravity tank in upper wing center section. one 150-gallon tank in engine section behind
firewall, one 160-gallon tank in mid section below floor of pilot's cockpit, one 105-gallon tank in
tail section underneath rear cockpit, and one 62.5-gallon tank in each lower wing butt. System is
operated by two gear pumps, one in reserve, controlled by pilot. For emergency, an oscillating
hand pump is placed in the cockpit.
Oil is carried in two terne plate interconnected tanks mounted underneath engine. Shut-off
valves are provided so that either tank may be cut out as desired . T\he forward tank holding twenty
gallons slopes upward, conforming to the contour of under-cowling at the nose. Thirty gallons
of oil are carried in the rear tank making a total capacity of fifty gallons.
A shutter-equipped honeycomb radiator having 5 and 7-inch core sections with former in the
center is mounted on nose of fuselage with the cooling surface above the engine bearers to reduce
restriction of air flow from the cowling projection at the rear to a minimum. The outside core
sections are practically free air surfaces. A reserve supply of water is kept in a 10-gallon tank
located in pilot's coch1)it. This water is injected into cooling system by means of an air pump.
In addition to the engine starters of which both electric and hand types will be supplied, the
equipment specifications provide for electric landing and running lights of the latest approved de­sign,
adjustable windshields, radio receiving and sending apparatus, and other recently developed
navigation instruments such as the Earth inductor compass, flight indicator, drift meter, aerial sex­tant,
and radio direction finder.
AIRCRAFT DEVELOPMENT 7
As soon as performance tests have been completed on the experimental D-WC airplane which
was flown to McCook F ield in October, this airplane wi ll be flown to Langley F ield , Virginia, for
water tests with pontoon equipment.
CHARACTERISTICS
DIMENSIONS
Overall span . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50' 0"
Overall length ....... ... ... ..... ..... ... ... ..... . .. .. .. ... ·. .35' 2-1 / 2"
Overall height . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13' 17-1/ 4"
Span with wings folded .. .. . .. ...... ·. . . . . . . . . . . . . . . . . . . . . . . 20' 2"
Span of wings ( upper and lower same) . . . . . . . . . . . . . . . . . . . . . . . 50' 0"
Chord of wings ( upper and lower same) . . . . . . . . . . . . . . . . . . . . . . 7' 6"
Di hed ral ...... .. ... .... . .. . : . ..... ........ . ....... . .. 0° upper, 2° lower
Incidence .... .. ... . . . . .. . . .. .. . .. ....... .- .. .. . .. ... . . 3° upper, 3° lower
Gap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8' 0"
Stagger .. . . . ... . .... . ·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . None
Sweepback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . None
AREAS
Total supporting surface ( incl. ailerons) ... . . .. ........... .. . .
Upper wing .... .. . .... ... .. .. ... .... . . . . .' .. 308.5
Lower wing . .. .. . .. ... .. ..... . : . . . . . . . . . . . . 328
Ailerons ( upper only) . . . . . . . . . . . . . . . . . . . . . . . 57.5
Elevators .... . ........ . .. . . . ....... . ... ... . . ....... .... .
Fin . . . . ........ . . .. .. _ ...... .. .......... .... .... . . . ..... .
Rudder . ..... .... .. ......... .... . .. . .. ....... . ...... . ... .
Stabilizer ..... .. . ........ .. .. . ... .. .. .... . . .... .. . . ..... .
WEIGHT (Estimated)
Empty (incl. water ) ....... .... .... . . ..................... .
Useful load ...... .. ... .. ... .. .. .... . . .................. . .
Crew . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360
F uel ... . . ...... . . .... .. ... .... . ..... . .. . .. 3600
Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375
Extra water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Total load ........ ... .. .. . ... ...... . ..... . .. ..... . ...... .
\ ,V eight per sq. ft. of supporting area .. .... .... .. ... ... . · ..... .
Weight per horsepower (1 Liberty 420) . .... ... .. . .. ........ .
Total load as seaplane .... ....... . ... .... .......... . ...... . .
PERFORMANCE (Estimated)
Average cruising speed . .. . .. ... . . ..... .. .. ... .. .. .. .. . . . . .
E ndurance . . . .. . . .. ...... . . .. . .. . ... ........ . ....... . ... .
Average fuel consumption . . ................. . ..... . . . ..... .
Range ... .... ... ...... ............ . .. ........ .. ...... .. .
BOMBARDMENT
NBL-1 (Barling Bomber).
694 sq. ft.
34 sq. ft.
12.25 sq. ft.
22.8 sq. ft.
63 sq. ft.
4268 lb.
4559 lb.
8827 lb.
12.5 lb.
21 lb.
9587 lb.
80 111. p. h.
27.5 hr.
22 gal. / hr.
2200 miles
Performance tests on the Barling Bomber are being conducted by the Engineering Division
at \i\Tilbur \,V right F ield, Fairfield, Ohio, in acco rdance with proposed plan outlined in Technical
Bulletin No. 35 in which a series of flights will be attempted using progressive loads up to maxi­mum
called for in the specifications.
8 T E CH N I CAL B UL LET I N N o. 36
In a preliminary test, the NBL-1 loaded with bombs weighing 4,655 lb., 400 gallons of gas,
and 40 gal. of oil, together with radio equipment and crew of three, reached an altitude of 6,800
feet as indicated by the instruments. In this flight, a maximum speed of 95.5 m. p. h. was obtained
over the speed course. In a later test, an altitude of 5,000 feet was attained with the following load:
Bon1bs .............................. : .... . ................. .
Fuel ( 365 gallons) ......... . .......... . .. . ... . . . ........ . .... .
Oil ( 72 gallons) . . ..... . .... .. . . .. ... ....... . ............... .
Radio equipment ........................ . ... . ................. .
Crew (2) ........................... . ....................... .
Radio operator and a mechanic caxried a s extra load ....... . ....... .
Weight of airplane empty, incl. -water . ... .. .... . ...... . . . . . . . ... .
Gross weight . . ... ... .... . ....... ... ..... ... ...... . . . · ....... .
6,690 lb.
2,190 "
540"
83"
400"
400"
27,132 "
37,435 "
It is planned to continue tests with increased loads in increments of approximately 1,000 kilo­grams
(2,204 lb.) to obtain complete performance data with full military complement. Whether
these tests can be accomplished before the encl of the present year is doubtful as considerable time
has been consumed in exhibiting the Barling at various places thruout the country and in mak­ing
minor changes incident to conducting performance tests. Recent inspections of the wing fabric
and other exposed parts disclosed that it may be advisable to recondition this airplane before at­tempting
further flights. The above weight-carrying flights were officially observed by representa­tives
of the N. A. A. for homologation.
Proposed Changes on NBS-l's.
As previously mentioned in last number of Technical Bulletin, several changes have been pro­posed
to provide efficient radiator cooling and to in sure satisfactory engine operation at high alti-·
tudes on the new supercharged NBS-1 bombers recently constructed by the Curtiss Aeroplane and
Motor Corporation, preparatory to releasing these airplanes to the service. The trouble has been
experienced not only with the radiators but with cold oil, frozen fuel- pumps, and cracked and
leaky cylinder jackets.
In an effort to overcome these difficulties, the Engineering Division equipped one of the
bombers that was used in the recent bombing tests at Langley Field with new cowling and su­spended
the radiators below the nose of the nacelles. Another NBS-1 bomber without super­charged
equipment was fitted in the same manner for entry in the St. Louis races. This airplane
made a high speed of 110.3 m. p. h. on a trial flight over speed course at McCook Field, which
performance is a considerable improvement over that of the standard production model.
GROUND ATTACK
Engineering Division GA-1. .
In connection with the improvement of the· GA-1. armored airplane, ten of which were built
by the Boeing Airplane Company for the Service, the Engineering Division has completed six sets
of revised landing gear axle assemblies for shipment to San Antonio Air Intermediate Depot,
Texas. The improved chassis incorporates a single 44 by 10-inch wheel in place of the two 36 by
8-inch wheels formerly used.
A sample nacelle constructed of welded steel tubing to replace the present armored nacelles
has been completed in the Engineering Division's shops for shipm·ent to San Antonio also. By
substituting the new nacelles, a saving of 800 pounds will be affected without affecting balance of
aii·plane. A considerable improvement in performance is anticipated as a result of these changes ..
OBSERVATION
New DH-4M and DH-4M-l (Boeing).
During the present year, the Air Service placed several contracts for the rehabilitation and re­modeling
of the standard service American-built DH-4 airplanes, several hundreds of which are
now in storage, into a more modern type of obser vation airplane to be known as the DH-4M and
DH-41\-1-1.
AIRCRAFT DEVELOPMENT 9
The first contract was awarded by the Engineering Division last February to the Boeing Air­plane
Company, Seattle, Washington, for three experimental airplanes of the new type to be known
as the DH-4M. Under this contract, three standard Class II, DH-4 airplanes from government
stores were to be rebuilt with steel tubular fuselages , the first airplane ,to be completed only in so
far as it was necessary to permit static tests of the new fuselage. The second and third articles
were to be fully completed and delivered to the Sanely Point Reserve Airclrome for flight tests.
The new DH-4M is essentially the same in general construction as the original DH-4 and the
improved DH-4B airplai1es except for the new steel tubular fuselage which is designed to permit
the use of as many DH-4 parts as possible, such as wings, tail surfaces, landing gears, cowling,
radiators, tanks, internal fittings, and other equipment. The new fuselage weighs approximately
the same as the original DH-4 fuselage ( 300 lb.) and is designed to carry an underslung fuel tank
under development by the Engineering Division as a tentative solution of the fire hazard in case
such development proves feasible. In performance, air worthiness, maneuverability, and general
flying qualities, the DH-4M is to be at least equal to the standard DH-4B model.
All three experimental airplanes on the first contract have been completed, the first one having
been static tested at contractor's plant last April. Performance ·tests on the other two are still in
progress at the Sanely Point Reserve Airdrome near Seattle.
In June, 1923, a second contract (A. S. Order 11.73-23 ) for 50 production DH-4M air­planes
was awarded to the Boeing Airplane Company of Seattle by the Air Service Procurement
Section at ·washington, D. C. Under terms of this contract, the principal changes to be incor­ated
in the production DH-4M design and which differentiate it from the original DH-4 are as
follows:
1. Entirely new fuselage of welded steel tubing.
2. Use of standard DH-4 or DH-4B wings.
3. Lowering of pilot's seat to accommodate parachute.
4. Relocation of ignition batteries on account of change No. 3.
S. Provision for installation of Type A-3 bomb racks and L-10 release handle.
It has been proposed to increase fuel capacity of the production DH-4M to 110 gallons as
this fuel capacity appears to be most advantageous from the service point of view. The original
DH-4B had a capacity of 88 gallons which was furth er decreased to 83 gallons when leakproof
tanks were used. By carrying the controls outside the fu selage, the 110-gallon tank installation
can be made without much difficulty. An installation of this nature in which the control system
was faired on outside of the fuselage has been successfully carried out by the Engineering Division
on a DH-4B airplane at McCook Field. Final decision has not yet been reached in this matter.
A third contract (A. S. Order 1403-23) for converting old DH-4's and DH-4B's into prac­tically
new airplanes to be known as DH-4M-l's was placed in July wcith the above-mentioned firm
thru the Air Service Procurement Section at Washington. The specifications on this contract which
calls for 100 airplanes provide for the following improvements :
1. Entirely new fuel system using wing tanks and engine-driven fuel pumps.
2. New 14-gallon oil tanks.
3. New straight-side 36" x 8" chassis wheels to replace Palmer 900x200 mm. equipment.
4. Substitution of K-3 camera for K-1. ·
S. Main fuel tank removed from fuselage and space thus available converted into com­partment
for baggage.
6. Substitution of one .30 caliber Browni11g synchronized gun for two .30 caliber Marlin
g-uns formerly carried.
7. New instrument board with padding in center, cut-away cowl and new windshield.
8. Installation of standard compass on cowling directly above instrument board and
within windshield.
The fir st change enumerated above, that is, the installation of an entirely new fuel system em­ploying
wing tanks, is apparently of greatest magnitude in the construction of the new DH-4M-1
airplanes. Two designs have been proposed by which this modification can be accomplished, one
by the contractor .and the other by the Air Service. The contractor proposes to use new upper
and lower wings and new center panel with main fuel tanks located in upper wing, whereas by the
Air Service plan a new lower wing only is required for the fuel tanks to be placed therein.
10 T E C H N I C A L B U L L E T I N N o. 36
The principal advantage of placing the main fuel tanks in the lower wing lies in the fact
that there is a marked increase in safety from fire in event of crash. Flight tests conducted by
the Engineering Division at McCook Field with a DH-4B airplane equipped with tanks in lower
wing have demonstrated this location as an improvement in certain respects, the balanc~ being prac­tically
perfect and the flying qualities unimpaired. The speed and landing speed, however, appeared
to be lowered.
In event the Air Service plan is adopted, certain parts of the original DH-4 lower wings
could be used such as spars, compression members, end pieces, trailing edges, fittings, etc., and
new parts made such as tank supports, ribs, stringers and the like, necessary to rework wing into
one of thick section (Gottingen 387) to accommodate two 55-gallon fuel tanks, one on each side
of fuselage. The upper wing and center panel used on the present DH-4B could be used without
modification for the DH-4M-l. The fuel capacity under this plan would total 118 gallons with 8
gallons in the gravity tank in the center section.
For purposes of trying out the Boeing Company's proposal, a fourth contract (A. S. Order
1441-24) was placed with this company for three sets of experimental wings and three sets of
split type axle landing gears. The wing design includes new upper and lower wings using a
Gottingen 436 airfoi l, a tw'o-bay cellule with streamline wires and a new center section containing
two 55-gallon main fuel tanks. The landing gear design embodies steel tubular struts and a split
or divided axle having a tread of 120 inches.
With either plan, the removal of the fuel tank from the fuselage leaves a space that may be
utilized for a baggage compartment entered thru a simple cover in the cowling. A new firewall
placed further aft and provided with a sliding door permits the contemplated installation of a
"Perfect" Type S compressed-air engine starter.
PURSUIT
Fokker PW-5.
Several months ago, the Engineering Division instituted an investigation to determine the
causes of wing flutter and other reported unsatisfactory performances of the Fokker P\i\T-5 pur­suit
monoplanes, ten of which were built for the service by the Netherlands Aircraft Company
(Fokker) of Holland. As previously stated in Technical Bulletin No. 33, nine of these air­planes
were delivered direct to Selfridge Field, Michigan, for acceptance tests after which they
were shipped to Kelly Field, Texas, for service test; one production PvV-5 being retained at Mc­Cook
Field for investigation.
The investigation disclosed that wing vibration or flutter which was believed to have caused
the collapse of the original experimental model, the "V-40," in flight ( see Technical Bulletin No.
24), has been prevalent to a more or less degree in all of the production PW-S's delivered to the
service notwithstanding the fact that the wings of these airplanes were specially strengthened dur­ing
manufacture so that deflections as determined by actual test were reduced to less 1han one-half
of those found in the wing of the experimental model under identical loads. It has been concluded
that the sofar successful resistance of the production wings to flapping is clue to their stronger
construction rather than to the removal of the ca uses. Early in the present year when the in­vestigation
was begun, all pilots were cautioned to always wear parachutes when testing these air­planes
until the cause of vibration had been clefin itel y establi shed. J uclging from the conclusions
arrived at in this study, there is a, possibility that all P\i\T-S 's in the service may be declared
unsafe for flying.
TRAINING
Huff-Daland TW-5C (Modified "Petrel").
A modified "Petrel," a two-seater training airplane of biplane construction designed and built
by the Huff, Dalancl and Company, Inc., Ogdensburg, N. Y., has been received at McCook Field
for inspection and test to determine the flight characteristics for use in connection with the new
contract for five T\i\T-5 airplanes awarded ·this firm as discussed in Technical Bulletin No. 35.
AIRCRAFT DEVELOPMENT 11
The equipment used in the "Petrel" which was given Air Service designation "TW-SC" consisted
of a Wright Model E, 180-h. p. engine, and certain instruments loaned by the Government and
installed by the contractor. The "TW-SC" is similar in general design to -the Navy HN-1 tandem
training seaplane of which the Army TW-5 will be a modification, except that the T\iV-SC has
been made into a three-seater by widening front cockpit so that two persons can sit side by side.
In a flight test over the speed course, a high speed of 112.48 m. p. h. at 1825 r. p. rn. was
obtained. In a later test a speed of 110.9 rn. p. h. at 1690 r. p . m. was obtained by using a semi­adjustable
pitch propeller having micarta blades set at a 16° pitch at a radius of 48 inch from the
hub. The latter performance was practically the same as that obtained with a wooden propeller at
1850 r. p. m.
Several changes were made by the Engineering Division during the flight tests to improve
the flying qualities. The most important of these was raising the rear encl of the engine so that
the center line of thrust passed thru the center of gravity, thereby producing the same flight char­acteri
stics with power either on or off. Stability and controllability were further improved by re­ducing
area of the horizontal tail surfaces.
At the conclusion of the tests at McCook F ield, the TW-5C was flown to the Naval Air
Station at Pensacola, Florida.
Thomas-Morse Training.
Perforn:iance tests have been conducted on the new chummy trammg biplane manufactured
for the Engineering Division on a government-loaned equipment contract by the Thomas-Morse
Aircraft Corporation, Ithaca, N. Y., with the following results:
High speed@ 1760 r.p. m. (corrected).. . .... . ........... 117.06 m. p. h.
One climb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16,300 ft.
Rate of climb at ground ....... ... . . ...... . . .. 1,120 ft. per sec.
Theoretical absolute ceiling .. .. ... . ... ... ..... 19,500 ft.
Actual ceiling during climb .... ...... ......... 16,300 ft.
Theoretical service ceiling . . ......... .. .. ..... 17,800 ft.
Actual service ceiling obtained in climb .. . ..... 15,800 ft.
The apparent falling off in climb at or near cei ling can undoubtedly be attributed to the use
of the incorrect etigine r. p. m. above 12,000 feet.
The new Thomas-Morse product is a two-place, externally-braced biplane powered by a 200-
h. p. Lawrance J-1 air-cooled radial engine. The wings are of conventional design, symmetrical
in span and chord, with the ailerons, four in all, inserted in trailing edges at the tips. The fuselage
is of the monocoque type with front section reenf arced by steel tubular trussing somewhat similar
to that employed in the Thomas-Morse R-5 racer. Corrugated metal sheathing is used for the
covering. The side-by-side seating arrangement possesses excellent advantages for close com­munication
between pilot and student but somewhat obstructs visibility on opposite sides from
the occupants on account of the excessive width of the fuselage to accommodate the double seats.
MISCELLANEOUS
Comparison Wings, for Messenger.
Six sets of wings for the Messenger airplane have been designed about six well-known airfoils.
three of which have been furnished on contract by the Lawrance-Sperry Aircraft Company and
the remainder by the Engineering Division. These wings are of the same areas to permit aero­dynamical
comparisons in actual flight tests. Of the three sets received from the contractor which
conform to the USA-27, USA-35, and USA-35B airfoil sections, the first has been installed on the
Messenger and flight tested over speed course in comparison with the Gottingen 387 wing with the
fo llowing results :
Eng. Div. Gottengin 387 wings ................ . .. ..... ... . .. . 84.85 m. p. h.
Sperry USA-27 wings, 1760 r. p. m ...... ... .. ..... .. . . .. ..... 89.95 m. p. h.
These tests will be continued until the entire series of wings have been tested. Aeroclynamical
characteristics of these different sections made up into small scale models are being compared by
the Division in the McCook Field 5-foot wind tunnel.
12 T E CH N I CA L BU LL ET I N N o. 36
Chassis Failures on SE-5A Service Airplanes.
The attention of the Engineering Division has been directed toward the elimination of main­tenance
troubles experienced with some of the n ew SE-SA pursuit airplanes recently manufac­tured
for the Service by the Eberhardt Steel Products Company, Buffalo, N. Y. The principal
difficulty has been due to 11:he numerous failures of the metal landing gears with which these. air­planes
were equipped.
In order ·to determine what corrective measures should be adopted, the Division requisionecl
two landing gears for comparative static tests.. One of these, a wooden gear with a 1-1/ 2-inch
axle, was obtained from the Fairfield Air Intermediate Depot (F. A. I. D. ), Ohio, and the other,
a standard gear with welded steel struts, from the contractor.
In the static tests, the wooden gear with vari ous modifications including an axle of larger
diameter (1-3/ 4 inches) withstood a drop of 48 inches under half-load but fail ed at a drop of 24
inches with full load. T he metal chassis equipped with a 1-3/ 4-inch axle also, withstood a drop
of 54 inches under half-load but failed at a 27-inch drop with full load. .
It was concluded that the metal gear can be used by welding an additional reenforcing mem­ber
between the upper extremity of forward strut and the lower extermity of rear strut and by
employing cross-br~ce wires ; the wooden gear which is similar to the one designed for the SE -5, ·
can be used by employing a larger axle ( 1-3/ 4 in ches in diameter ) and cross-brace wires. The
adoption of the wooden gear would probably be preferable because it could be easily supplied by
various Air Service depots if required whereas the welding of the metal gear as clone by some sta­tions
that are improperly equipped for this work might prove unreliable- see di scussion on "Cracks
in Welded Steel Struts" on page 27.
AIRSHIPS AND BALLOONS
RS-1 Airship.
The envelope patterns for the RS-1 semi-rig id air ship under construction .by the Goodyear
Tire and Rubber Company, Akron, Ohio, are being designed. These patterns are to be made to
one tenth scale for determining the correctness o f shape. Layout of the fu el system has been de­cided
upon and the design is proceeding. Designs for the keel members and power car structure
are in progress with that of the former in readiness for checking. Stress analyses of the nose cone
are being revised and the analysis of the control surfaces is nearing completion.
An air blower has been developed by the Goodyear Company for maintaining pressure in the
ballonets of the RS-1 envelope. The blower consists of a Harley-Davidson gasoline motorcyd e
engine fitted with special fan and Venturi capable of delivering 5,000 cubic feet of air per minute
against a pressure of one inch of water. Tests for capacity and endurance are to be run , in which
the blower will be operated at capacity for 120 minutes again st the required · static pressure. The
fuel consumption, static and velocity pressures and volumetric del iveri es at variou speeds will be
determined at this time.
The Engineering Division has also designed a blower unit for this airship that will deliver twice
as much air under same static head as the unit de veloped by the contractor. Altho designed along
similar lines, the larger unit employs a Harley-Davidson motor-cycle engine modifi ed to give in~
creased power thru the substitution of new cylinder s, pistons, and crankcase. T he blower has a
larger fan and Venturi and is capable of delivering 10,000 cubic feet of air under same condi­tions.
Bids have been asked for the construction of the modifi ed engine for driving the blower.
The engine is to be a two-cylindered, four-cycle, air-cooled motor weighing not over 45 pounds and
measuring 25 inches or less in overall width. Requirements for the acceptance tests will be as fol­lows:
( a ) One hour run delivering eight hor sepower at 2000 r. p. m.
(Engine to run for five minutes at 3000 r. p. rn .)
(b) Engine must idle smoothly at less than 400 r. p. m.
( c) Design shall insure easy starting when cold.
( cl) Design should permit use of muffl ers if latter a re found necessary.
AIRCRAFT DEVELOPMENT 13
The 17-1/ 2 foot Balsa propeller which was designed and built at McCook Field for use on
's airship has successfully completed 10 hours of a contemplated SO-hour run at 750 h. p. as
furnished by two Liberty engines thru the power transmission with which the RS-1 is to be driven.
The results thus fo.r obtained have been sufficiently satisfactory as to warrant the construction of
two add itional propellers of this same design.
TA and TC Airships.
The first of the new Army Class A airships. the T A-1 , to be built by the Goodyear Tire and
Rubber Company, has been completed and delivered to Scott Field, Belleville, Illinois, for erection.
A sister ship of this same d~sign, the TA-2, is also nearing completion. The special feature which
characterizes the design of the TA airship is that air pressure in the ballonet is maintained by
tractor propellers forcing air thru passages in the engine outriggers instead of by scoops hung from
the envelope as in the usual practice.
The principal design characteristics of the TA airships are as follows:
Volume ..... .. . . ................ ... .... . ... . ... . ... ..... 130,000 cu. ft.
Length overall ...... .. ............................. ...... 162 feet
Maximum diameter , ................... ... ...... . ......... 39.2 feet
Crew .... ... ........ . .......... .. . ........ ....... .. .... . 3 persons
Power plant (Two Curtiss "OX-5" engines at 70 h. p. each) . ..... 140 h. p.
Maximum speed .. . .............. . ... . . ... ......... . ...... 45 m. p. h.
Endurance at full power ........ ...... ........ .. ........... 10 hours
Endurance at one-half power ... .. . ....... _ ..... ............. 20 hours
Range at full power ....... .... ....... .. ...... . . ... ... ..... 450 miles
Range at one-half power ...... . . ...... .. .............. . .... 720 miles
Service ceiling .... . . ............. . ............ . .......... 6,000 feet
In regard to 'i:he three additional TC airships. the TC-4. S, and 6. which are to be constructed
by the Airship Company, Inc. , Hammondsport. N. Y. , under supervision of the Engineering
Division. it has been proposed to equip the fir st two airships with 150-h. p. \ i\Tright Model I en­gines.
the same as used in the TC-1 , 2, and 3 air ships built by Goodyear. and to install at 210-
h. p. Lawrance J-1 air-cooled engine in the TC-6 for comparative test with a view of increasing
power and decreasing weight. The design of a new outrigger to accommodate the Lawrance en­gine
in stallation on the TC-6 has been started.
At the contractor's plant. the car structwes for the TC-4. S. and 6 have been strengthened
to with stand a factor of 6 or more when statically loaded. Drawings for the control surfaces have
been carefully checked and one set of surfaces constructed.
The Engineering Division has conducted tests at McCook Field on two water models of the
TC envelope ballonets, one model being provided with two individual ballonets similar to those
used on the earlier built TC-1. 2, and 3 airships and the second with a single centrally-divided
ballonet, to determine the superiority of the respective designs.
The first model has been given a series of tests in which photographs were taken showing de­formation
for pressures corresponding to 0. 1/ 4. 1/2. and 1 inch of water with ballonets full and
empty. These photographs have been compared with those of the second model subjected to
similar tests to determine relative deformation of the TC envelope using two single or one double
ballonct under identical conditions of pressure. pitch. and fullne ss. As a result. the single ballonet
with a gas-tight partition at the center of volume has been decided upon for the TC-4, S and 6 air­ships.
Following these tests a model of the Military AC-1 airship car will be attached to each of
these water models for determining the adaptability of the TC method of suspension and the
fea sibility of using this car on this airship. In this connection, an analysis has been made of the
stresses for the TC envelope.
Engineering data is being prepared by the Division for the proposed purchase of several new
airships of the TC class next year.
•
14 T E CH N I CAL B U LL ET I N No. 36
New Barrage Balloon and \Winch.
The Engineering Division has instituted extensive research work in connection with the de­sign
of a special barrage balloon for operating at an altitude of 15,000 feet. As a preliminary ex­periment,
it is proposed to construct a test balloon similar to the A-P observation type but having a
capacity of 20,000 cubic feet, that can be anchored by a 1/8-inch cable to an experimental winch
of modified French design which is now under construction.
The French type of winch was selected for its simplicity and dependable features after a thoro
investigation of the adaptability of different types of winches for high altitude barrage balloons,
and as a result a modified design has been made incorporating the most desirable feature s. The
new winch will be driven by a standard four-cylinder Ford automobile engine which can be easily
obtained in quantities and will be designed for mounting upon a two-wheeled trailer for easy trans­portation.
Certain improvements will be incorporated in the design to make it adaptable to Ameri­can
shop methods for quantity production.
Cabinet for High Altitude Balloon.
An airtight metal cabin designed for withstanding internal pressures en.countered in high alti­tude
work has been completed by the Eberhart Steel Products Company, Buffalo, N. Y. Leak
tests are being conducted at the contractor's plant prior to shipment to McCook Field. The seams
of the cabinet which is built of aluminum sheeting supported by duralumin members, are riveted,
then welded, to form permament airtight joints. After inspection by the Division, the cabinet will
be sent to Scott Field, Illinois, for actual flight te sts.
New 20-Inch Gas Valve (Goodrich).
A new 20-inch gas valve which promises to be a decided improvement over present standard
18-inch valves is being constructed by the Goodrich Rubber Company. In the new design, the
number of moving parts has been reduced, thereby eliminating considerable friction and making
the valve more sensitive to variations in pressure. Based upon tests of 28-inch valves of similar
design which have been approved for use as air valves in the Zodiac airship, the 20-inch valve should
operate within a variation of 1 mm. of water at the operating pressure setting .
Tractive Tests of Highly Mobile Winch.
Comparative tractive tests of the highly mobile balloon winch as equipped with caterpillar
adapter and dual-tired rear wheels have proved the superiority of the latter equipment for general
utility. The winch, as originally built, was mounted upon a four-wheel-drive, pneumatic-tired
chassis which greatly increased its mobility over the ordinary rear-wheel-drive truck, particularly in
negotiating very soft ground. To further increase the performance on marshy terrain. the En­gineering
Division designed and constructed a caterpillar ;adapter which could be applied over the
pneumatic wheels without change. It was lateT found from extensive tests that the excessive weight
of the adapter reduced the mobility of the winch except over extremely marshy ground and that
the use of dual tires on the rear wheels would greatly reduce weight and permit full performance
under practically all conditions. The application of dual tires to the rear wheels reduced the unit
pressure per square inch on the ground to about 11 pounds and greatly increased the roadability of
the winch, especially in soft gravel and mud. Altho the caterpillar adapter operates satisfactorily
over very marshy terrain, it is conceded that the dual tire equipment is more advantageous for
general purposes.
Parachute Release for Balloon Basket.
A safety device which is radically different fr om all other appliances for like purposes, both in
its construction and in its operation, has been developed by the Division at McCook Field for ef­fecting
the instantaneous release of the basket from the balloon. In general construction it is a
suspension rigging bar embodying a basket parachute release. The rigging bar, which is made of
wood reenforced by metal strips, is composed of two halves, each resembling a letter "L" inclined
at a slight acute angle, which when joined and rigged to the balloon, form an equilateral triangle
having its vertex toward the balloon. The two side bars are joined at the top by a pivot bolt
AIRCRAFT DEVELOPMENT 15
and are provided with a spacer to allow free jack-knife action in opening. At the bottom they are
clamped 'by an aluminum casting carrying two steel studs which are inserted into the two metal re­enforced
holes, one in each side bar. A safety latch retains these studs in place. Resting upon
the lower or horizontal member of the triangle formed by the sides of the rigging bar is a large
parachute encased in a triangular-shaped pack that fills the center of the triangle. The parachute
is held in place by a small cord attached to pivot bolt.
To effect a release, the safety latch is turned
thru an angle of 90 degrees releasing the studs.
This allows the aluminum frame to drop, thus
withdrawing the studs from the holes in the L­shaped
side bars which automatically spread open
under weight of the basket and its contents. The
rigging bar is attached to the balloon and the
parachute to the basket.
Owing to the method of looping the basket
suspension to the side bars and the attachment of
the latter to the balloon rigging, when the two
studs a re withdrawn from the holes, the side bars
spread open, ·releasing the basket rigging loops
from the two cleats secured on the in side of these
bars. The parachute is fastened to the basket
rigging which is looped around the side bar cleats,
so that in descending with the parachute, nothing
but rope lines intervene between the parachute
and the basket. The particular advantage of this
feature is that when the basket rebounds in land­ing
there is no rigging har or metal piece hanging
directly overhead as in the case of the French
release, to strike and injure the occupant of the
basket, not considering the additional weight im­posed
on the parachute.
T he outstanding features of the Engineering
Division's design are, namely: safety as assured
by a fou l-proof method of attachment, the posi­tive
and instantaneous release from balloon, and
unlikeliness of injury in landing with parachute;
ease of operation; minimum weight, and low cost
of production. The safety and ease of operation
features have been positively substantiated by
BASKET PARACHUTE RELEASE. tests. In connection with the weight and cost, it
is estim.ated that the former can be reduced from
25 to 30 per cent, whereas the cost of production ought to be considerably lower than for existing
types owing to the fact that this rigging bar is built almost entirely of wood with only a few metal
parts, entailing a minimum amount of labor and material in its manufacture.
ARMAMENT
British Course-Setting Bomb Sights.
Thru the request of the United States Military Attache at London, two British course-setting
bomb sights, Mark II, for high altitudes from 1500 to 14000 feet and Mark lA for low altitudes
from 300 to 2500 feet, have been delivered to the Engineering Division for test from the Gasco
Conipany, the New York representatives of Elliott Bros., London, E ngland. These sights have no
stabilizers or pilot directors but embody many improvements over the earlier British types as well as
the Mark III bomb sights used by the United States Navy. Altho the structural improvements of
the British sights are excellent, the principle of operation does not permit the accuracy obtainable
16 TE CH N I CA L B UL LET I N No. 36
with some of the new sights recently developed by the Engineering Division for the U. S. Army
Air Service. The operation of the British sight depends chiefly upon the direction and velocity
of the wind, whereas our new sights permit approach from any direction regardless of these fac­tors.
As a navigating instrument and for Naval bombing at very low altitudes, the British l\fark
lA sight is an improvernent over our Navy Mark III bomb sight.
Gun Sight, Type X-9.
A new sight, designated as T ype X-9, has b een developed by the Engineering Division for
GUN SIGHT
TYPE X-9
Ring Setting
for minimum
speed.
similar gear in the adjusting screw AS. This
arrangement permits the manipulation of two
bronzes slides S and S by rotating the adjusting
screw by means of the knob K. The ratio of the
gears incorporated in this device enables the eyelet
E which is mounted at the upper end of the frame
F to be maintained in a central position in rela­tion
to the ring R which actuates upon the sup­porting
pin P. The entire assembly is accom­plished
without the use of screws or other parts
liable to loosen under vibration, by means of the
elevating screw retainer unit RU consisting of
a retaining clip and stud.
This gun sight, which has been thoroly
ground and air tested by the Division may be
substituted for the present ring flexible gun sight
(110-mile range) to obtain adjustable compensa­tion
for speeds ranging from 115 to 140 m: p. h.
The X-9 ring sight, a few units of which have
been produced for experimental purposes, is
identical in application to the ring sight already in
use on flexible guns thruout the service.
use on the standard .30 caliber Lewis aircraft ma­chine
gun. This sight is designed so that it .can
be easily and quickly adjusted without the use of
tools to compensate for varying enemy speeds
whereas the present sight used in the Service is
fixed so that all variations in enemy speeds must
be compensated for by approximation. In using
the new sight, the approximate speed of the enemy
airplane may be judged by its silhouette depend­ing
upon whether it is an alert, pursuit, observa­tion,
or bombing type, and the sight set accord­ingly,
just prior to actual combat.
The ring sight "X -9," illu strated herewith,
consists of the following parts with reference to
the the accompanying drawing. The aluminum
frame F which is con structed so as to fit into the
standard ring sight socket on the Lewis gun re­ceives
the slide frame assembly SF which con­sists
of the aluminum slide frame and steel stud .
The steel elevating screw ES surmounted by the
cap C carries the spiral gear that meshes with a
GUN SIGHT
TYPE X-9
Showing Ring
Attachment
Test of Bomb Rack B-3.
AIRCRAFT DEVELOPMENT
p ----
11------R
E
-~---====~=:=--s
ES
- -------F
SECTION THRU CENTER -
SECTIONAL VIEW OF GUN SIGHT, TYPE X-9.
17
Static tests were conducted at McCook Field on the external bomb rack, Type B-3, which is
a modification of the old Mark XVI bomb rack designed and constructed by the U. S. Ordnance
Department for carrying two 100 or two 300-lb. demolition bombs for use on DH-4 airplanes,
with the result that the carrying assembly exclusi ve of beams withstood a factor of 7 or 4200 lbs.
A permanent set of 5/ 64" was observed in the angle brace on the safety block slide after removal
of load whereas the deflection at this point during the application of the maximum load measured
9/ 64-inch.
Mark I Gun Camera.
Altho it has been stated that European countries are far advanced in the perfection and use
of gun cameras, recent tests conducted by the Engineering Divi sion have demonstrated conclusively
that the Mark I gun camera together with the time-recording device developed for the United
States Signal Corps by the Eastman Kodak Company during the \ i\Torld War, is more satisfactory
than any of foreign make. These tests were made by substituting the gun camera for the Lewis
magazine on the regular Lewis aircraft machine gun. The Mark I gun camera for which com­plete
production drawings are being made, will he in stalled in accordance with foreign practice on
the wing of an airplane directly in the line of sight for further tests.
Two kinds of film have been developed for this camera, one is similar to ordinary motion pic­ture
film and the other is a special sensiti zed paper which can be deYeloped into a positive print in one
operation.
Flare Rack and Release Handle, Type M-2.
The development of the M-2 flare rack and release handle was undertaken by the Engineering
Division for the purpose of providing a mechanically-operated mechanism that can be universally
applied to any type of airplane now in the service for carrying and releasing the standard Mark I
parachute flare. The new M-2 flare rack supersedes the old Mark I flare rack developed by the
United States Ordnance Department.
18 T E C H N I C A L B U L L E T I N N o. 36
The rack which is 55 inches long and weighs only 1-1/2 pounds, is designed in such a way
that the carrying or releasing mechanism is mounted entirely within a metal tee rail of such length
that it can be insta]led without modification on the wing of any service airplane. By referring to
the illustrations on opposite page, it will be noted that the rack is a very compact unit consisting of
a formed sheet duralumin tee rail TR provided with several lightening holes for reducing weight
and facilitating inspection. At the front end of the rail ( at right of drawing), a safety retainer
arm RA, com;pressed by a spring RS, intercepts the arming vanes on the nose of the flare to pre­vent
their rotation. The assembly is designed so that this arm can be turned sufficiently to allow ·
the assembly or removal of the f.use without removing the flare from the rack. Two stabilizers Y
or inverted Y-shaped supports riveted to the rail at the proper distance apart to accommodate the
flare tube lugs serve to steady the flare when mounted on the rack. These same supports or arms
help form the sockets in which the lugs of the flare are carried. Two carrying hooks H made
of cyanide hardened steel and actuated by a tie bar B attached to their upper extremities are ful­crumed
to the tee rail. These hooks are locked in position by means of a lock bar L and sprmg
LS backed by a casing stop.
The locking device is controlled from the cockpit -by the M-2 release handle described in the
following paragraph thru the use of a Bowden type of control cable and casing. The lower end
of the latter is held in position by the casing stop CS that is bolted to the tee rail. The control
cable and casing can be easily detached from the rack by removing a special clevis X, thereby per­mitting
the removal or replacement of the rack without interference with the control cable.
l"""===)
C
T
s
C5
RC
TO IJE. CUT TD PROPER~
LENGTH AT INSTALLATION ~
RELEASE HANDLE FOR PARACHUTE FLARE RACK "M-2"
The release handle unit M-2
for releasing the parachute flares
consists of t~o handies, one for
each ·rack, supported on a mount­ing
plate for instaUation in the
cockpit of the airplane. The as­sembly
consists of two tubes T
and T welded to the mounting
plate MP which is lettered to
designate the flares controlled
by each respective handle. Each
tube is bent outward from the
plate so as to provide clearance
for 'the handle when turned. The
collar C that is welded to the
upper encl of the tube is notched
to receive the stud encl of the
aluminum. handle H. In this
manner the number of flares on
the racks is indicated. The handle
is held in position by means of a
compression spring S enclosed in
the tube between the collar at
its upper end and the sleeve,
sweated to release cable, at its lower encl. The ends of the release cables are securely soldered to
the handles. A casing stop CS is inserted in the lower encl of each tube to receive the ferrule of
the flexible casing of the Bowden type thru which the release cables RC transmit the impulse to the
release mechanism on the rack.
In single installations, the release handle unit should be securely mounted in a position that
will permit its operation by the pilot's right hand. This arrangement is recommended because of
the fact that in any airplane the pilot would be greatly benefited by control of the flares during
forced landing at night. A second handle may be installed for the use of the gunner or bomber if
desired. In order to insure maximum safety at all times, the Mark I parachute flare, without
the fuse, should first be securely and properly fastened to the rack. The vane retaining arm should
then be rotated and the fuse assembled just before the airplane leaves the ground.
A small quantity of M-2 flare racks and release handles have been built and sent out to the
Service for test under actual service conditions with a specific request that a detailed service test
report be submitted to the Engineering Division on the relative merits and general application oi
this new equipment.
r_
NEW PARACHUTE FLARE RACK, TYPE M-2.
(Showing ins tallation of rack and fla re on lower wing of DH-4B Airplane.)
cs TR
;~1-------- -:s---·-· I 11 1
(\ 1
1
1 I 11 1
1
I · · I
,__ )_,___.J_L__--_-_--_--_-_-_-_- /7 ___~ JI JIL _ ___ (
ILLUSTRATIVE DRAWING OF PARACHUTE FLARE RACK, TYPE M-2
(Letters refer to description in text on opposite page.)
20 T E CH N I CA L B U LL ET I N No. 3h
POWER PLANTS
Tests on British Engines.
An air-cooled 350-h. p. Siddeley "Jaguar" 14-cylinder radial engine obtained from the British
Government several months ago has been fitted to a DH-4B airplane by a special mounting which
was used on this same airplane for flight testing the \ i\1 right 350-h. p. 9-cylinder radial. Upon
completion of this installation flight tests will be conducted to determine comparative perform­ances
of these twlo radial engines. A SO-hour te 3t of the "Jaguar" was started last June only to be
postponed until cooler weather, due to the fact that it was imposible to operate this engine on the
torque stand under the weather conditions then prevailing.
The Engineering Division is also conducting a standard engine test on
dor" Series l A, 12-cylinder water-cooled aeronautical engine of 650 h. p.
engine was disassembled for the photography ancl weighing of parts.
Diagram for Liberty 8 and 12-Volt Ignition Systems.
the Rolls-Royce "Con-.
Prior to the test, the
The diagram shown above was prepared by the E ngineering Division for the purpose of ex­plaining
the difference between the standard 8 and 12-volt ignition systems as used on the Lib­erty
"12" engine. The standard installation for the 12-volt system is indicated by the heavy lines
and that for the 8-volt system by the shaded lines. This chart is to be di stributed to all air sta­tions
in the Service in an attempt to clarify the numerous misunder standings regarding the correct
in stallation of these t'vvo systems.
Ll:FT Dl5TRIBllTOR RIGHT Qt5TR1BJJTOR
- §ENERATOR.
APPARArV.5 BOX.- 5517
~-HOT U.5EQ
1~ f~~';~~~~E~~~~OR
LcuTOI.Jf RELAY AS-'EM6Ll'-s1s1
6&t1....._
MIL._
r51ELD
<iROONO
<iEN.rlELD -
~ - c· l:¢'~~-1'-'f'-14,
GEN. ARM
VOLfA(ie REGULATOR
~ -A55EMBL'(-57ZI
1LJQ!J -Nor useo
SWITCH
~tci'~~,: l~;XMBY-13784} n \OLT
~:'tJ:'lcttJt~CMBi.Y·IS<l."J!J IZ VO• l
2 12 VOLT 5ATTERIE5-045175•
{ A!i~~MBLY 1120
~ -RE515TANC~ UNIT5{:;V;~,-_~,g~:;: SWITCH-04~.?,38 •
r <,."JENEILY ·04!>.3Z<;•
RE'-.515TANCE UNIT5{:~~~=~~i~T
CONNECTOR-.33U>l.3
• AIR 5~RVICC PAR'T NUMEIER5
ALL OTHER5 ARE DELCO N<.JMBER5
NQTE-BI\IJERY AND VOLTAGE RE~ULATOR SHOWN
CONNECTED B,"'f DOTTED LINES ARE U5E D
WITH B VOLT .5Y5TEM. ONLl
DIAGRAM OF 8 AND 12-VOLT IGNITION SYSTEMS
(For Standa,rd Liberty "12" Engine.)
AIRCRAFT DEVELOPMENT 21
•
New Packard Engine, Model lA-2500.
The Engineering Division is negotiating a contract with the Packard Motor Car Company,
Detroit, Michigan, for the design and construction of three aeronautical water-cooled engines,
known as the Packard Model lA-2500. This engine is to have the following characteristics:
12 cylinders, water-cooled, V arrangement.
Individual steel cylinders with aluminum camshaft housing.
Displacement of 2500 cu. in.
Guaranteed horsepower of 800.
Guaranteed weight, not over 1135 lb.
There is a possibility that these engines might be used in the 1924 Pulitzer racers altho this
new 800-h. p. Packard engine is not designed primarily for that purpose. The engine is intended
for use in bombing airplanes and possibly in high speed observation types also.
Bellows Fuel Pumps.
The report of the Engineering Division representative who visited the factory of the Keuka
Industries at Hammondsport, N. Y., to inspect the production of bellows fuel pumps being manu­factured
for the Service states that altho this work is progressing satisfactorily it will be necessary
to make certain changes on· the drawings and to allow certain deviations therefrom in order to ex­pedite
delivery. These revisions have been grantee! and it is thought that the shortage of these
pumps will be speedily overcome.
•
•
RESEARCH AND EXPERiMENT
I
RESUME OF ENGINEERING DIVISION
SERIAL REPORTS.
Serial Reports marked with an asterisk (*) wiil
be issued by the Chief of Air Service as "Air
S qn1ice Inf or111atif)n Cfrcufars."
AIRPLANE SECTION
Stress Analysis and Design of R-3 Fuselage.
•
Serial No. 2160
This report covers analysis and structural design computations on a welded steel fuselage for
the Verville-Sperry Racer, Model R-3, as equipped with a high-powered ·wright 380-h. p. engine
and retractable chassis. It !is illustrated by numerous tables and stress diagrams showing fuselage
truss at various loadings imposed by different conditions of flight.
Characteristcs of Sperry Venturi. Serial No. 2163
A test was conducted last June in the McCook Field Five-foot wind tunnel for the purpose of
determining the pressure-volume characteristics of a 10-3/4-inch Sperry gyroscopic double Ven­turi
for use in connection with a pilot director developed by the Engineering Division. The range
of pressures and volumes of the Venturi used as an air-pumping or power device were determined
for speeds varying from 80 to 180 miles per hour by means of a Durley 1/ 4-inch orifice and the re­sults
reduced to terms corresponding to the use of such a Venturi in actual flight.
Calibration of Small Orifices for Sperry Venturi. Serial No. 2194
A test was conducted in the McCook Field small ( 14-inch) high-speed wind tunnel for the
purpose of calibrating two sm?,ll nozzles ( diameter 0.0935) · used by the Sperry Company in
measuring volume of air flow' in the gyro. double Venturi mentioned under Serial No. 2163 in order
to make the results obtained in these tests comparable.
In the method of testing, the Durley orifice box was connected so as to discharge into a special
"Sperry Orifice Box" which in turn discharged into the orifices of the wind tunnel, the source of
suction. By varying the suction in the tunnel different volumes were caused to flow thru the
two orifice boxes in succession, the drop across each orifice being recorded by manometers. The
ratio of these drqps in pressure determined the relative coefficients of the respective orifices.
In the previous test in the 5-foot wind tunnel, an orifice coefficient of .6 was adopted. In the
present test, the small Sperry orifices show a coefficient of .073. This may be stated to show com­parison
of orifice drops under same volume of fl ow as follows:
a. Single Sperry orifice--the drop in pressure is 34.2 times that of the Durley orifice.
b, Double Sperry orifice-the drop in pressure is 8.58 times the drop of the Durley
~~- .
Test of Longren Fiber Fuselage. Serial No. 2205
Static tests conducted by the Engineering Di vision on a Longren fiber fuselage of the 'Mes­senger
type disclosed that this type of fuselage was structurally satisfactory for sm,all commercial
airplanes and that with proper reenforcement can be made into a very satisfactory type of construc­tion
for small airplanes .
•
RESEARCH AND EXPERIMENT 23
The Longren fuselage is a monocoque structure having a cockpit large enough to accommo­date
a pilot and a passenger by a staggered seating arrangement. It is built in seven sections, joined
at the top and bottom on two longerons extending from front bulkhead to tail post. The material
is vulcanized sheet fiber .080 to .083-inch thick, shaped in a mold or die under heat and pressure
and then cemented and screwed to laminated wood bulkheads. The skin or outer covering is
weather-proofed, pigmented, and then varnished to ·give a good fini sh.
The entire structure complete with furnishings and tail skid weighed only 162 lb. and sup­ported
the required factor of safety of 6 without signs of failure. Final failure occurred at factor
of 9 due to the fact that the fiber skin was improperly supported at the bulkhead joints, · indicating
that the structure was no stronger than the bulkheads on which the fiber skin was glued.
Test of Loening PW-2 Wing. Serial No. 2208
A monoplane wing of wood and fabric cons truction for use on Loening PW-2 pursuit air­plane
was subjected to static tests and supported the required factors without failure. Views of
the cellule, typical spar, and rib sections are included along with several deflection curve charts.
ARMAMENT SECTION.
Pyrotechnics on DH-4B Airplanes. Serial No. 2138
In this report will be found complete instructions for the installation of pyrotechnical and
night flying equipnient on DH-4~ airplanes, to-wit:
Section I- - Mark I Airplane Flare.
Section II-Wing Tip Flares.
Section III-Running Lights.
Section IV-Exhaust Equipme nt.
Several drawings are appended covering the installation of the following equipment.
1. New M-2 parachute flare rack and release handle.
2. Heat, light, and oxygen equipment.
3. Electrical equipment including switch panels, lights, etc.
4. Exhaust manifold and extension piping.
Bomb Release Handle L-4. Serial No. 2170
11his report constitutes a questionnaire for a report of the Service test on the bomb release
handle "L-4," an improved type of bomb control handle or bell crank for pursuit airplanes de­veloped
for operating the recently modified A-2 bomb racks ( old Mark XVIII). A photograph
and assembly drawing of the handle are appended.
Machine Gun Synchronizer, Type C-2. Serial No. 2171
Service test requirements on the new C-2 machine gun synchroni zer which is a modification of
the Type C-1 synchronizer (Nelson gun control) to allow the impulse cable to remain slack when
the gun is not firing are set forth in this report. This modification has three principal advantao-es;
first, it perm:its the installation of an automatic gun controlled by a machine gun synchroni~er; .
second, it eliminates accidental firing of gun which might result from tampering w1th operating
bracket on control stick of airplane when engine is not running; and third, it increases the life of
the impulse cable by removing the tension when it is not in use.
Machine Gun Synchronzer, Type C-3. Serial No. 2172
The machine gun synchronizer, _Type C-3, is a modification for use with Type C-1 synchro­nizer
in which the impulse cable is flexibly installed. This is accomplished by using a semi-flexible
tube anchored at both ends, thru which the cable actuates. This modification is particularly ad­vantageous
in the designing of airplanes as it al lows more freedom in the location of fuel tanks,
firewalls, cowling and other vital parts. It eliminates the thrust tube formerly required and with
it considerable inconvenience as a different length of tube was required for each type of air­plane.
Requirements for service test and several photographs of this device are given.
24 Ti E CH N I CAL B U LL ET I N N o. 36
Machine Gun Synchronizer, Type C-7. Serial No. 2173
This development was conducted to produce an automatic advance for use with machine gun
synchronizer, Type C-1. A device of this kind isadvantageous in synchronizing the fire of .SO
caliber and .30 caliber machine guns with four- bladed propellers.
The Type C-7 synchronizer as constructed f or service test, a report of which is to be sub­mitted
to the Engineering Division upon completion, is designed for use on a W right (Hispano­Suiza)
300-h. p. engine, for installation in a Thomas-Morse pursuit airplane which is a particular
ly difficult gun installation.
As in previous service test requirements repo rts complete views and installation details are
given.
Bomb Release Handle, Type L-5. Seiral No. 2174
This service test requirement report contains complete description, photographs, and detailed
information necessary for the application of the Type L-5 bomb release handle to the Type A-2
bomb racks ( modified Mark XVIII ) . This han die incorporates a means for actuating the releas­ing
and arming mechani sm on the bomb rack in such a way that a double installation is afforded
for dual control.
Gu°: Sight Type X-6. Serial No. 2175
The Type X-6 gun sight is designed for use on flexibly-mounted aircraft machine guns. It
provides an angular correction adjustable to speed of airplane upon which it is mounted and a
compensation for approximate speed of the enemy airplane. In operation, it is necessary to know
the approximate range of the enemy airplane for which purpose a range-finding device is incor­porated.
The sight fits into the standard sight sockets on the Lewis .30 caliber machine gun.
The report contains a discussion illustrated by numerous sketches on the theory or principle of
operation. Service questionnaire and views of the device are also given.
EQUIPMENT SECTION.
Night-Flying Equipment.
Instructions for the installation of electrical equipment required for night flying are given 111
the fo llowing reports for four different types of service airplanes.
Serial No. 2214.-MB-3A Pursuit.
Serial No. 2215-JN-6HB Training.
Serial No. 2216-DH-4B Observation.
Serial No. 2217-MBS-1 N-ight Bomber.
Each report contains specific instructions regarding the changes and additions that are neces­sary
to properly install electrical night-flying equipment on each particular type of airplane, such
as running and 'landing lights, switch panels, electric generators, starting motors, and storage bat­teries.
A wiring diagram, harness, and list of parts necessary for installation are given also.
FL YING SECTION
Drag Characteristics in Free Flight. Serial No. 2197
A method of determining the drag characteristics of the cellule and other parasite parts of
an airplane in free flight has been established by the Engineering Division as based upon the satis­factory
results obtained from a series of flights described in this report.
Various methods of test have been evolved from time to time but the procedure and interpre­tation
of these tests have prevented their more extensive application, the main difficulties arising
therefrom being the elirn:ination of negative propeller thrust and the effect of vertical currents. A
few reference works may be cited in which these methods are described as follows :- National Ad­visory
Committee for Aeronautics' report of October, 19 18, on "Resistance of an Aeroplane De­termined
by Glides with Propeller Stopped" which gives an account of British tests at Farn­borough
and Engineering Division Serial Report No. 1242 on "The Use of the DeBothezat Per­formance
Chai t in Airplane T,esting," giving an account of tests of Vought VE-7 at McCook
F ield. The National· Advisory Committee have also made extensive developments along this line
at Langley Field from which a method of finding the true angle of glide in flight with reference
to the earth but not with reference to the pressure level that is susceptible to change on account
of vertical currents, has been evolved.
RESEARCH AND EXPERIMEN T 25
The procedure in the present tests requires the use of no special equipment except a super­sensitive
barograph. The airplane is flown to a high altitude where the air is calm and a series
of glides made between 2000-foot a ltitude levels at several different but constant indicated air
speeds. In addition to holding constant air speeds, the pi lot maintains a constant rate of propeller
revolutions which rate is predetermined theoretically to give zero thrust.
With clue consideration of the practical aspects of the problem of obtai.ning drag characteris­tics
from gliding tests, it is concluded that the m ethod given in this report is sufficiently accurate
and convenient to give results within the limit of error of other measurements made on the air­plane
without the use of special apparatus. Therefore it is recommended that this method be used
as standard procedure in the evaluation of aeronautical cha racteristics and engine-propeller design on
all airplanes submitted to the E ngineering Divis ion.
MATERIAL SECTION
Investigation of "Z-D" Process. *Serial No. 2149
Due to the fact that corrosion and porosity of light allows have always been a source of clan-·
ger to the functioning and life of certain parts of the airplane, particularly the fuel system, an
investigation of the Z-D process was undertaken by the E ngineering Division to determine its
effectiveness as a coating to inhibit corrosion, minimize porosity, and produce certain desirable
physical properties of aluminum, magnesium, and their a lloys.
The importance of protecting these parts may be forcibly illu ~tratecl by citing a few instances
in which samples of sediment taken from fuel systems were submitted for examination. A short
time ago, a sample of deposit taken from a fuel strainer of an airship, had plugged the fuel line so
completely that the engine ceased to function. A second in stance of a dangerous nature was that
in which a, carburetor bowl of copper-aluminum alloy became corroded sufficiently to stop the flow
of fuel thru the jet. In another in stance, an aluminum fuel tank from a Junker airplane was
found to contain enough sediment to prove a serious menance to the functioning of the fuel lines.
In regard to formation of deposit in carburetor bowls it appears that a protective coating ap­plied
thereon would prevent the corrosion that eventually causes the accumulation of objectional
sediment. In an earlier investigation it was found that this corrosion of aluminum and its al­loys
was not caused to any noticeable extent by the fuel, itself, but by the presence of water in
the fuel system. For these reasons, a rriore extensive appli cation of the Z-D process was carried
out.
It was found that this process of coating whi ch consists, broadly speaking, of successively
heating the metal to be coated (if a change in physical properties is desired); quenching in a suit­able
medium, then immersing in a warm aqueous solution of sodium silicate or water soluble sili­cates,
and finally baking without washing, preve nts cor rosion of aluminum (possibly magnesium)
and its alloys more effectively and efficiently than any other inorganic coating. ·
Many foteresting photographs of treated and untreated surfaces are appended.
Organic Coating for Duralumin. Serial No. 2184
T his investigation is a continuation of the de velopment of a protective coating for cluralumin.
It combines the results of service and panel exposure tests which were begun in 1920. The service
tests were made by applying the different coatings to the surface of a Junker all-duralumin air­plane
which was then exposed to atmospheric and flying conditions. The panel tests were made in
accordance with standard procedure for exposure of organic coatings except that sheet duralumin
w'as substituted for tinned steel.
Of the several coatings and primer tested it was found that two coats of aluminum enamel
consisting of 73.6 per cent approved spar varni sh and 26.3 per cent aluminum powder withstood
both panel rack and service tests perfectly and gave better results than any other organic coating
tested, over a period of twenty-one months.
Heat Treatment of Al-Cu Alloys. Serial No. 2185
This experimentation was undertaken to ascertain the proper heat treatment for a harden­ing
temperature of 925° F. to develop the best combination of streng.th and ductility in sand or
chill cast aluminum-copper a lloys, with or without magnesium, ancl simultaneously to study the
metallographic structures. It was founcl that aluminum-copper alloys containing magnesium re­spond
to heat treatment more readily than those without, ancl that it was impossible to correlate the
micro-structure of these alloys with their physical properties.
26 T E CH N I CA L B UL LET I N No. 36
POWER PLANT SECTION
"Flash-Over" Altitudes of Spark Plugs. Serial No. 2134
In this interesting laboratory investigation it was found that the tendency of spark plugs to
"flash-over" :at high aJtitudes under supercharged engine conditions increases directly as the spark
gap, and is greater with the standard A. C. porcelain plug than with the various mica plugs used
by the Air Service. An auxiliary spark gap in series with the spark plug slightly increases this
tendency. However, there is ample margin of safety against "flash-over" at altitudes that are
attainable at present, provided the spark plug gaps do not exceed fifteen thousandths of an inch.
Performance Tests on Foreign-Built Aeronautical Engines.
The Engineering Division has completed dynamometer tests o.n three well-known aeronautical
engines of foreign manufacture to determine their design characteristics and performaqce. Each
report contains complete details of the test and numerous photographs of the engines and vital
parts as follows :
Serial No. 2191-LeRhone 9-c11. 160-h. p. Rotary .Engine, Model Rm.
Serial No. 2193-Bristol "Jupiter" 9-cyl. 400-h. p. Radial Engine.
Serial No. 2218-Siddeley "Jaguar" 14-cyl. 320-h. p. Radial Engine.
INVESTIGATION OF MATERIALS
Babbitting Directly on Steel.
The process of babbitting directly on steel, thereby eliminating the bronze back used in present
conventional practice has been studied by the Eng:neering Division with the result that several en­gine
parts have been successfully babbitted in this manner. In one method of procedure, a good
bond was obtained between the babbitt and a case-hardened steel engine bearing by first applying a
tin coating to the bearing. The tinning was accomplished by applying zinc chloride-HCI acid solu­tion
to the carefully-cleaned steel surface without preheating and then immediately immersing the
part for approximately one minute in bath of molten tin held at 600° F. The part was then placed
in a cast iron mold which had been preheated to about 300° F. and the molten babbitt poured
rapidly. The pouring temperature of the babbitt was found to be satisfactory at 720° F. Close
temperature control of the metals both in the tinning and in the babbitting operations is essential.
The correct temperature for each particular case can best be determined by trial, as temperatures
that are too high result in "draws" and "shrinks" and those that are too low, in "mis-runs" and
cold "shuts."
In connection with the study of babbitting connecting rod bearings directly to steel without the
use of an intermediate bronze liner, representatives of the Division visited the plant of the Mar­mon
Motor Car Company, Indianapolis, Indiana, who are using this method in automobile pro­duction.
The variable factors of the process, such as the pouring temperature of the babbitt, the
temperature of the mold, the method of tinning, etc., were noted and a sample of the babbitt
brought back for analysis in the Division's laboratories. It was found that the metallographic
structure of the bearing metal used by the Marmon Company was normal and that the chemical
constituents correspond very closely to the bearing metal described in A. S. Specification No.
11,013, with the exception that the lead content ( 0.40%) exceeded the maximum allowable.
The new method of babbitting should have extensive application and is to be used on the new
type of connecting rod for the 18-cylint!er Model W-lA engine.
Rubberized Fabric (Vulcan)
A piece of 3-ply rubberized fabric manufactured by the Vulcan Proofing Company as a sample
of envelope material for use in the new TC airships which are to be built for the Air Service by the
Airship Company, Inc., Hammondsport, N. Y., has been examined. It was found that this manu­facturer
thru the application of certain suggestions advanced by the Engineering Division has pro­duced
a superior fabric to that previously made by this firm for the Army A-6 airship, the U. S.
M.B.
RESEARCH AND EXPERIMENT
Cracks in Welded Steel Struts.
27
An examination of a steel tubular strnt taken from the landing gear of an SE-S airplane at
France Field, Panama Canal Zone, disclosed that the final failure resulted from cr:.icks that had
FAILURE OF SE-5 STEEL LANDING GEAR STRUT
(Arrows indicate cracks in tubing adjacent to weld.)
gradually developed in that por­tion
of the tube ad iacent to the
weld. It appears that these cracks
which are characteristic of weld­ed
tube construction have been
found in several instances to have
been caused by a difference in ex­pansion
of vario1.1s members of
the assembly during localized
heating in welding- which quite
naturally induces ex c e s s iv e
stresses in the material adjoining
the weld. That portion of the
tube which becomes heated to
practi cally the same temperature
as the weld, itself, is weakened
and since it does not have the ad­vantages
of an enlarged cross­section
clue to the addition of
welding material, it is susceptible
to cracks. Such cracks are gen­erally
microscopic at first, but
under continued vibration they
are gradually widened until insufficient cross-section of the tube is left to carry the loads and
failure r esults.
Aluminum Alloys for Large Castings.
The E ngineering Division has investigated the application of some of the recently developed
aluminum alloys as suitable material for large castings. T he four alloys under investigation were
alloy No. 1, a standard Air Service 8 per cent copper alloy, Specification No. 11 ,023, that is used
exten sively for crankcases, intake manifolds and miscellaneous castings ; alloy No. 4, A. S. Speci­fication
I 'o. 11 ,300, which is heat-treated duralumin; alloy No. 5 containing 3 per cent copper and
4 per cent silicon, developed in the McCook Field foundry; and Alpax metal of 13 per cent
silicon. T he tests were made by casting Liberty 8-cylinder engine crankcases from each of the
alloys and studying the physical properties of te st specimens cut from similar light and heavy
sections.
It was concluded that the standard Air Serv ice Alloy No. 1 which is obtainable from any
reliable foundry, has superior physical and casting properties and therefore cannot be replaced
by any of the others except for special castings. It was demonstrated , however, that alloy No. S
is more suitable for castings in which great foun dry losses are encountered on account of shrink­age
or cracks and in thin sections less than 3/ 16-inch thick. Alpax metal is not recommended on
account of its low proportional limit and duralumin, alloy No. 4, on account of its tendency to
c,ack in the quenching operation.
A casting of a crankcase from this pattern is being made by the E licktron Metal corporation
by using a magnesium-aluminum alloy which weighs about two-thi rds as much as Air Service Al­loy
Jo. 1 and has approximately the same physical properties.
Value of Specifications in Purchase of Bronze
Specimens of gun metal manufactured by the Federal Bearing and Bushing Corporation,
were also investigated by the Division due to the fact that this manufacturer alleged discrimination
in connection with a purchase of some bar stock in conformity with A. S. Specification No. 11 ,020.
A chemical analysis of the specimens revealed a lead content of 0.38 per cent whereas the specifi­cation
requires less than 0.20 per cent. T he physical and metallographic properties were found in­ferior
to the bar stock actually furni shed on this order by the successful bidder.
28 T E C H N I C A L B U L L E T I N N o. 36
The procedure in handling this order demonstrates the value of using specifications for pur­chasing
in p,reference to specifying certain commercial grades of metal. For instance, the original
purchase order and drawings called for "Non-Gran" bronze or equivalent, "Non-Gran" being the
trade name of a bronze manufactured by the American Bronze Company. The Division requested
the substitution of A. S. Specification No. 11 ,020 for the "Non-Gran" or equivalent metal with the
result that a bronze of superior quality was obtained at a lower figure, so far as could be determined
by comparison of sam,ples of "Non-Gran" previously furni shed with the gun metal furnished on
the present order.
Aluminum Bronze (Frontier).
Aluminum bronze manufactured by the Frontier Bronze Company for the Curtiss Company for
making the aluminum bronze ring used in their self-starter s. was examined by the Engineering
Division to determine its suitability to resist the high compressive stresses demanded by this
service. The chemical composition of the metal was found to consist of 89.5 per cent copper, 1.0
per cent iron, and 9.5 per cent aluminum. The physical properties upon heat treatment and
quenching in brine at 1600° F. showed a Brinnel hardness of 275 which decreased to 255 upon
subsequent drawing at 650° F. Tensile strength after drawing was 85,000 pounds per sq. in., with
an elongation of 1.5 per cent in 2 inches. This material is exceptionally hard for a non-ferrous
alloy.
Sediment in Fuel Strainer (Smith-Richter Endurance Flight).
A 100-rnesh fuel strainer from a Lukenheimer valve which became clogged during re-fueling
operations in the recent endurance flight of Lts. Smith and Richter at Rockwell Field, Coronado,
California, was forwarded to the Engineering Division for a chemical analysis of the sediment
found in the screen. An examination of this sediment under the microscope revealed that a mat
of linty fibrous material consisting principally of asbestos with some cotton fibers had formed
directly against the screen causing the accumulation of earthy matter to clog the strainer. Chemical
analysis of this earthlike substance di sclosed compounds of zinc and iron with former in pre­ponderance.
It ,is believed that the asbestos and cotton lint came from the lini.ng of the refueling
hose and the zinc and iron from the reenforcing wire used in this hose.
Durii1g this flight in which re-fueling of airpl ane was accomplished 'in the air, 787 gallons of
gasoline were supplied from the fueling airplane thru a special hose covered with cotton fabric on the
outside, then a layer of rubber and finally a flex ible steel coil insert in which each coil was separated
by asbestos cord. Before reaching the strainer of the Lunkenheimer valve, this gasoline passed thru
three strainers of fine mesh. At times the clogging became so bad as to endanger the continuance
of the flight, temporary relief being afforded by tapping the valve with a wrench to dislodge the
sediment.
Paravar Coating.
An investigation has been completed on Para var, a new protective coating developed by the
United States :Rubber ,Company as a substitute for spar varnish and other similar coverings used
on wood, metal , or cement. This coating is made from a rubber base. It dries very quickly, form­ing
a hard, transparent film that turns white and opaque when immersed in water for any length
of time. The outstanding feature of this film is its apparent resistance to water penetration. Upon
outside exposure, all panels covered with Paravar warped whereas those to which spar varnish
had been applied did not.
Paravar does not compare favorably with approved spar varnish for outside exposure and re­duces
protective qualities of the latter when used as an undercoat. Its permeability to hydrogen
gas is very great on envelope fabrics subject to wrinkling and its use as a gas film would be of
little value except upon surfaces that remain rigid at all times. Results obtained from the tests
do not warrant the usage of Paravar in aircraft construction.
· Specification for Waxed Linen Thread.
A specification has been prepared for waxed linen thread to be used for serving rope splices,
whipping rope ends, whipping eye splices ' and the like. The necessary material investigation and
testing was done by the Division as a result of the suggestion !"ubmitted by the Goodyear Tire and
Rubber Company, airship manufacturers, that iinen thread 'is better suited for this purpose than
the cotton cord originally specifi ed.
RESEARCH AND EXPE Rl MENT 29
This specification has been approved recently as a standard War Department specification by
the Quartermaster Technical Committee.
Turner Shock Absorber Ring.
Tests have been made on Turner shock absorber rings received thru our Military Attache in
London. T his r ing is made of rubber strands very similar to our present standard shock absorber
cord, except that it is an endless ring that can be applied to undercarriages without wrapping. T he
cord, itself, is of slightly higher quality than our standard cord clue to the use of a larger number
of rubber strands and a heavier grade of yarn in the covering. The use of a closed ring requires
standardized shock absorber saddles and, according to the price quoted, decreases the material cost
of the shock absorber unit between 300 to 500 per cent. The Turner ring, which is at present be­ing
used on the Barling Bomber, is illustrated below.
TURNER SHOCK ABSORBER RING
(As used on Barling Bomber)
•
NEW BOOKS AND DOCUMENTS
REFERENCE DATA ON AERONAUTICAL DEVELOPM'.,;NT
AND ENGINEERING IN THE UNITED STATES AND
OTHER COUNTRIES ADDED TO THE TECHNICAL FILES
OF THE AIR SERVICE ENGINEERING DIVISION.
AVIATION AND AEROSTATION.
Aviation spirit past,
by E. A. Deustan and
national Air Congress.
1923. 2 p.
present and future;
F. B. Thole. Jnter­London.
June 29,
Aeronautical notes; by Comm. Orthlieb; tr.
by Maj. C. H. Wash. M . I. D. France.
July 19, 1923. 31 p.
Contents:
1. Observation aviation.
2. Order and reports.
3. Stations and movements.
4. Various missions and .their execu­tions.
Standardiza,tion of symbols; by Command­ant
du G. E. Herrera.. International Air
congress. In French tr. Technical Data Sec­tion.
Memo. report No. 76. June 23, 1923 .
11 p.
Marking of aircraft; by Lt. H. J. Ruser­Larsen.
International Air Congress. Lon­don.
June 25, 1923. · 2 p.
Suggested min·or alterations in Inter­national
Air Congress; by Capt. R. N. S. T.
Lubeck. International Air Congress. Lon­don.
1923. 9 p.
Technical development of the airplane; by
J. D. North. International Air Congress. Lon­don.
1923 . 9 p.
GREAT BRITAIN.
Strength of Great Britain's Air forces.
Sept. 18, 1923. 1 p.
Dll.3/76
Al0/124
D61.2/40
A81 /17
AOO /48
D52.1 /133
C20.3/13
Annual report on civil aviation, Apr. 1, Al0.01 /3
1922-Mar. 31. 1923. Directorate of Civil G. Britain
Aviation. Air Ministry. 1923. 41 p.
Report of advisory committee for William D00.12/191
Froude national "tank" for year ending Dec.
31, 1922, made to the executive committee
of National physical laboratory. M. I. D.
England. 6 p.
Answer to questionnaire on winter fl.yin2" C71.6/43
in Canada. M. I. D. Aug. 15, 1923. 8 p.
Summary of civil aviation certificates and B00.6/3
Jicenses issued, cancelled, renewed and still . 1923-July
in force. Canadian Air Force, July 31, 1923.
Summary of civil aviation certificates and ROO 6 /3
licenses issued, cancelled, renewed and still 1923-Aug.
in force. Canadian Air Force. Aug. 31,
1923.
FRANCE.
Bombardment aviation; by Capt. Dagnaux; A70.1/53
tr. by Maj. C. H. Wash. M. I. D. France.
Apr. 12, 1 na. 22 p.
Report of accidents which happened at D52.l 9 /2
the glider and low-powered airplane con-gress
at Vauville. M. I. D. France. Aug.
21, 1923. 1 p.
Comments on French airplane and para- Al0/16
chute competitions. Prizes offered to aero- France
nautical constructors · whose airplanes make
world records. M. I. D. France. Aug. 2,
1923. 3 p.
ITALY.
Flying pay in Italian air force. M. I. D. . B40/2
Italy. July 2, 1923. 2 p.
Compensation for consumption during
navigat•on in airships; by Col. A. Crocco. M.
I. D. Italy. July 15, 1923. 8 p.
JAPAN.
Experimental metal airplanes under con­struction
for Japanese army and navy. M.
I. D. Japan. Aug. 3, 1923. l p.
UNITED. ST ATES.
Air Service activities of United States
army, giving station reports and Air Service
strength of commiss ioned regular army and
reserve corps. Apr. 30, 1923.
Comparison of balloon strengths of allied
and enemy Air Services. July 30 -Nov . 11,
1918. 4 p.
Monthly list of publications issued by the
Department of Commerce. July 31, 1923.
RECORDS AND PERSONNEL.
Preliminary report on international air
races at St. Louis, Oct. 4, 1923; compiled by
Technical data section. McCook Field. 5 p.
Winners of the Schneider cup. 1913-
1923. 1 p.
List of aircraft manufacturers who will
probably present seaplanes at Schneider cup
race to be held Sept. 27, 1923. M. I. D.
France. Aug. 9, 1923. 2 p.
Entr2.nts and winners in Gordon Bennett
race, 1911. 1 p.
Dll.32/44
D52.1 /9
Misc.
Japanese
C21-8
1923-Apr.
C20.3/12
Cl3/6
1923-July
D52.03 /68
D52.03 /70
D52.03/67
D52.03/6)
Report on course-croisire seaplane races. D52.03 / 55
M. I. D. France. Sept. 10, 192 3. 2 p.
Report of Porto Rican flight made by six C71.6/36
United States Army airplanes, Mar. 3rd to
Apr. 3rd, 1923. 82 p.
General considerations and training of air- C53 .222 / 16
plane observers ; prepared under direction of
Chief of Air Service. n. d. 13 p.
AERIAL NAVIGATION.
AIRD ROMES AND AIRWAYS.
Air mails, dealing with experience of Brit- El0.2/35
ish post office; by Brig. Gen. E. H. William-ron.
International Air Congress. London.
June 27, 1923. 4 p.
Description of air mail at Elko, Nevada. D00.12/179
Aeronautical bulletin No. 31. June 15, 1923. 1923-No. 31
2 p. Illus.
Des cription of Oakland stock farm emerg- DOO l • /179
ency landing field at Columbus, Ohio. Aero- 1923-No. 33
nautical bulletin No. 33, June 15, 1923. 2
p. Illus.
Information concerning ports of call for AOO /40
seaplanes and their tenders making passage 1923-No. 10
between Hampton Roads, Panama, and Guan-tanamo
Bay. Notice to Aviators No. 10.
Oct. l, 1923. 5 p.
Description of Swedish airdromes . M. I. FlO /43
D. Germany. June 28, 1923. 2 p.
METEOROLOGY.
Flying in fog. Tr. from Aero. Jan., 1923.
13 p.
A40.3/22
NEW BOOKS AND DOCUMENTS
Lecture on meteorology by Capt. Degnaux ;
tr. by Maj. C. H. W•ash. M. I. D. France.
May 2, 1923. 16 p.
REGULATION.
Regulations governing issuance of cert.Hi
cates of airworthiness of airciaft in Fr~nr.e.
From BuJletin de la navigatioa ael'ienne,
Mar., 1923. National Advisory Committee
for Aeronautics. Technical Notes No. 155.
Aug., 1923. 46 p .
INSTRUCTION.
AIR SERVICE ENGINEERING SCHOOL.
Course in machine shop practice. Air
Service Eng ineering School. McCook Field.
1923. 98 p. Drawings .
Course in Wood Shop Practice. Air Ser-vice
Engineering School. McCook Field.
1923. 9 p . Drawings.
GENERAL SERVICE SCHOOLS.
Outline of the courses of instruction avail­able
in United States Air Service Schools .
RESEARCH.
GENERAL AERODYNAMICS.
Reports and memoranda of Aeronautical
Research Committee published between Oct.
l, 1921, and Mar. 31, 1923. Aeronautical
Research Committee. Reports and Memo­randa
No. 850. May, 1923. 7 p.
New apparatus and equipment in aerody­namics
department of National Physical
Laboratory; by R. V. Southwell. Inter­national
Air Congress, London. June 25,
1923. 3 p. Illus.
Forest Products Laboratory. Technical
Notes No. 198-206. Aug. 15, 1923. 29 p.
Diags.
On CastigJiano's theorem of least work,
and principle of St. Venant; by R. V. South­we]
I. Aeronautical Research Committee. Re­ports
and memorada No. 821. Revised.
May, 1922. 22 p.
Fundamentals of fluid motion in relation to
aeronautics; by L. Bairstow. International
Air Congress. London .• June 27, 1923. 3. p .
Maneuvers of inverted flight; by R. M.
Hill. Aeronautical Research Committee. Re­ports
and Memoranda No. 836. Sept., 1922.
68 p. Charts.
Mechanics of Kohler rotating bar fatigue
test; by W. Mason. Aeronautical Research
Committee. Reports and memoranda No.
838. Sept., 1922. 8 p. Diags .
Report on investigation in progre::;:3 at
Bureau of Standards. Oct. 8, 19~3. 12 )).
Dynamic stability as affected by lougi­tu<
linal moment of inertia by E . B. Wilson.
National Advisory Committee for Aero­nautics
. Report 172. 1923. 8 p.
Continuous rotation balance for measure­ment
of Lp at small rates of roll; by E. F.
Relf and T. Lavender. Aeronautical Research
Committee. Reports and Memoranda No.
828. Aug., 1922. 4 p. Drawings.
Preliminary study of damping factor in
roll; by Lt. J. M. Shoemaker and J. G. Lee.
National Advisory Committee for Aero­nautics.
Technical Notes No. 161. Pct.
1923. 1 7 p. Charts, diags.
Stresses in stiff jointed polygonal frame
under system of paralled loads; by A. J. S .
Pippard. Aeronautical Research Committee.
Reports and memoranda No. 820. Aug.,
1922. 8 p. Diags.
Calculation of rotary derivatives due to
ya.wing for a monoplane wing; by H. Glauert.
Aeronatuical research committee. Reports
and memoranda No. 866. · Feb., 1923. 8 p .
Charts.
Some a s pects of modern aerofoil theory:
by H . Glauert. International Air Congres s .
London. June 27, 1923. 4 p . Charts.
Airstream around an aerofoil with auxil­iary
fore wing; by G. Lachmann. M. I. D.
Germany. July 13, 1923 . 15 p. Photo­stats.
A40 /26
B00.6/5
C53.13/6
Dl 1.1 /293
C52.22/17
D00.12/850
R. & M.
F32/18
D00.12/97
1923-Aug.
D00.12 /821
R. & M.
Al0.2/104
D00.12/836
R. & M.
D00.12/838
R. & M.
D00.12 /78
T. N. B.
Al0.2/108
D00.12/828
R. & M.
Al 0.2 /109
D00.12/820
R. & M.
D00.12 /866
R. & M.
D52.338/169
Al0.2/107
Interference of wind channel wans on
aerodynamic characteristics of an aerofoil;
by H. Glauert. Aeronautical Research Com­mittee.
Reports and Memoranda No. 867.
Mar., 1923. 7 p.
Description of lift, vertical-force and drag
balances for roof of duplex wind tunnel; by
T. H. Fews ter. Aeronautical Research Com­mittee.
Reports and Memoranda No. 823.
Oct., 1 n2. 4 p. Illus., drawings.
Singing of circular and streamline wires:
by E. F. Relf and E. Owen. Aeronautical
Research Committee. Reports and Memo­randa
No. 825. Mar., 1921. 4 p. Chart,
diags.
Measurement of t hrt:st anrl torque of
windmills; by J . A. Lo. M . I. T . 1921. 2 p.
Photostat, charts.
Lift and drag of Bristol fighter with wings
of three aspect ratios. Aeronautical Re­search
Committee. Reports and memoranda.
859. Apr., 1923. 23 p. Illus., charts.
Experiments on rigid R32. Part 1. Pres ­~
ure on upper fin and rudder; by J. R.
Pannell and others . Aeronautical Research
Committee. Reports and r...1emoranda No.
8ll. (Ae. 62). T. 1561. Feb., 1921. },Op.
Charts .
Experiments on rigid airship R. 32. Part
III. Measurements of res istance and air­speed;
by J. R. Pannell. Aeronautical Re­search
Committee. Reports and Memoranda
No. 813. June, 1921. 24 p. Charts, diag .. ...
Pressure distribution over n1o(fol of hull
of airship R . 33; by R. Jones and A. H.
Bell. Aeronautical Research Committee. Re­ports
and Memoranda No. 801. Mar., 1922.
37 p, Charts, diags.
Prediction of resistance of rigid airship
R. 33; by R. A. Frazer and A. G. Gadd.
Aeronautical Research Committee. Reports
and Memoranda No. 827. July, 1922. 23 p.
Charts, diags.
AIR FORCE AND MOMENT.
Air force and moment for M-80 D-2 wing
with baffle flap. Navy Yard. Construction
Dept. Report N o. 231. June 28, 1923. 9 p.
Charts .
Air forces and moments for N . W. sea­plane.
Nav,y Yard Construction Dept. Re­port
No. 232. Aug. 13, 1923. ·• 23 p. Pho­tog
raphs. drawings.
Forces and moments on RS-1 airship hu1l
with modified No. 3 control surfaces. Bureau
of Standards. Aug. 4, 1923. 7 p,
DESIGN AND STRUCTURES.
Influence of form of wooden b eam on its
stiffness and strength Part III. Stresses in
wood members subjected to combined column
and beam action; by J. A. Newlin and G. W.
Trayer. Forest Products Laboratory Pro­ject
L - 228-6 . Sept. 6, 1923. 28 p. charts,
photographs. ·
Effect of aerofoil thickness . and plan form
on lateral control; by H. I. Hoot. National
Aclvi sory Committee for Aeronautics. Re­port
No. 169. 1923. ll p. Illus., charts.
Load dis tribution along chord of aerofoil.
Navy Dept., Bureau of Aeronautics. Tech­nical
note No. 45. Reprinted from aircraft
technical note No. ll8. 1923. 2 p. Charts.
Fittings and other structural parts of air­planes;
by P . Eydam. From Technische
Berichte. Vol. 3-No. 6. National Advisory
Committee for Aeronautics. Technical Notes
No. 160. Oct., 1923. 12 p. Diags.
Influence of blocks and fillets on stren g th
of wooden memberg. Navy Dept. Bureau
of Aeronautics. T echnica l note No. 120.
Aug. 21, D23. 7 p. Diag.
Comparison of two methods of float plank­ing;
by H . I. Hoot. Special Testing Division.
Naval Aircraft Factory. Test 4S23-1A.
July 24, 1923. 7 p. Photographs.
Comparison of standard mailed cons truc­tion
with float planking made on Boston
wire stitcher ; by H. I. Hoot. Special Test­ing
Divis ion. Naval aircraft factory. May
25, 1923. 7 p .. Photograph, c harts.
31
D00.12/867
R. & M.
D00.12/823
R. & M .
D00.12/82 5
R. & M.
F78/69
D00.12/859
R. & M.
D00.12/811
R. & M .
D00.12
R. & M/813
D00.12
R. & M./801
D00.12/827
R. & M.
D52.338 /173
D52.6/ l
N. W.
D52.7 /6
RS-1
D 52 .331 /99
D 52.338/ l 74
D52.338/ l 72
D52.39 /130
D52.39/129
D52.62 /5
D52.62/4
32 T E CH N I CAL B U LL ET I N No. 36
Notes on design of ailerons; by Lt. W. S.
Diehl. Navy Dept. Bureau of Aeronautics.
Technical note No. 115. May 1, 1923. 8 p.
Charts. drawings.
Handley Page slotted wing; by H. Gallau­det.
Aeronautical Research Committee. Re­ports
and Memoranda No. 834. Mar., 1922.
8 p ., diags.
Strength and design check of 132-inch
metal ribs manufactured by Airships, Incor­porated.
Material Section. McCook Field.
Sept. 7, 1923. 4 p. Photograph.
On use of a slotted trailing flap on aero­foils
of various cambers; by F. B. Brad­field.
Aeronautical Research Committee. Re­ports
and Memoranda No. 865. Jan., D23.
9 p. Charts, drawings.
Method of calculating characteristics of a
tapered wing; by H . Gallaudet. Aeronautical
Research Committee. Reports and Memo­randa
No. 824. Oct., 1922. 8 p. Charts.
Attachment of main balance of 7 foot No.
2 wind tunnel for measuring three forces
moments; by T. Lavender and others. Aero­nautical
Research Committee. Reports and
Memoranda No. 822. Sept., 1922. 2 p.
Drawings.
TESTING.
Torsion tests of box beams; by T. R. C.
Wilson. Forest Products Laboratory. Pro­ject
L-228-3. Aug. 29, 1923. 64 p. Photo­graphs,
charts, diags.
Tests of four slotted aerofoils, supplied by
Messrs. Handley Page, Ltd., by F. B. Brad­field.
Aeronautical Research Committee.
Reports and Memoranda No. 835. Sept.,
1922. 16 p.
Test of experimental metal wing beams ;
by N. S. Otey. Testing Division. Naval
Aircraft Factory. June 26, 1923. 1 p.
Photographs, diag.
Test of fuselage fitting for N-2-N; by N.
S. Otey. Testing Division. Naval Aircraft
F_actory. Aug. 25, 1923. 2 p. Photographs,
d1ags,
Test of PN-7 aileron to determine whether
it will support a static load of 15 pounds
per square foot; by H. I. Hoot. Special Test­ing
Division. Naval Aircraft Factory.
Aug. 9, 1923. 6 p. Photographs, drawing.
·Test to check original design of PN7
strut; by N. S. Otey. Testing Division.
Naval Aircraft Factory. Aug. 24, 1923. 2
p. Charts.
Test on control sheave for ZR-1; by H. I.
Hoot. Testing Division. Naval Aircraft
Factory. Nov. 14, 1922. 1 p. Drawing.
Failure of SE-5 airplane landing gear
strut. Material Section. McCook Field.
Sept. 18, 1923. 1 p. · Photographs.
Test of ZR! control car struts ; by N. S.
Otey. Testing Division. Naval Aircraft
Factory. Sept. 13, 1923. 1 p. Chart.
Test of lower front hinge fitting for
N-2-N ; by N. S. Otey. Testing Division.
Naval Aircraft Factory. July , 26, 1923. 1
p. Photographs, diags.
Test of turnbuckles with defective bar­rels;
by H. C. Knerr. Metallurgical Labora­tory.
Naval Aircraft Factory. Aug. 13,
1923. 5 p. Photographs.
Calibration of Zahm venturi tube W-340
up to 250 m. p. h. WJnd tunnel. Mc­Cook
Field. Aug. 22, 1923. 7 p. Charts.
Direction and velocity meter for use in
wind tunnel work, etc.; by E. Lavender.
Aeronautical Research Committee. Reports
and Memoranda 844. Jan., 1 ~23. 2 p. Illus.
drawings.
Wind tunnel tests of five strut sections in
yaw; by E. P. Warner. n. d . 7 p. Charts.
AEROMARINE.
AIRCRAFT.
(Heavier-than-Air)
Description of Aeromarine United States
air mail night airplane. Aug. 29, 1923. 5
p. Photographs.
D52.322/15
D00.12/834
R. & M.
D52.332/77
D00.12/865
R. & M.
D00.12 /824
R. & M.
D00.12 /822
R. & M.
D52.331/98
D00.12 /835
R. & M.
D52.5 31/100
D52.39 /131
D52.322/16
D52.333/74
D52.74/53
D52.3 33 / 72
D52.333 /75
D52.39 /134
D52.39 /132
D13.3/10
Venturi
Tubes
D00.12/844
R. & M.
D52.333/73
D52.1 /1
Aerornarine
Photographs of Aeromarine all metal fly­ing
boat. Aug. l, 1923.
AVRO.
Handbook on Avro 504K. Air publication
No. 915. Air Ministry. June, 1923. 36 p.
Illu s .
C. A. M. S.
Description of C. A. M. S. s eaplane entered
in Schneider cup race. In French. M. I. D.
France. Aug. 9, 1923. 3 p.
De HA VILANp.
Lubricating axles on DeHaviland 4 air­planes.
Navy Dept. Bureau of Aeronautics.
Technical Note No. 119. July 25, 1923. 1
p, Drawing.
DeMARCEY.
Drawings of DeMarcay 4 Cl airplane.
n. d.
DA VIS-TORPEDO.
DT-2 airpl2ne performance. Navy Dept.
Bureau of Aeronautics. Technical Note No.
121. Sept. 15, 1923. 8 ,p. Charts.
Static test of DT-4 center section; by H.
I. Hoot. Naval Aircraft Factory. Test
3S23-l. Sept. 18, 1923. 5 p. Photo­graphs,
drawings .
FARMAN.
Characteristics of Farman primary rtain­ing
airplane. M. I. D. France. July 10,
1923. 1 p. Photographs.
Characteristics and descriptive pamphlet
on Farman limousine F . 70. M. I. D. France.
July 11, 3 p. Photographs.
HUFF -DALAND.
Photographs of Huff-Daland HN-2 Navv
training s eaplane, equipped with Lawrence JI
engine. n. d.
NIEUPORT.
Chart of characteristics of Nieuport­Macchi
seaplanes . In Italian. Feb., 1919.
PILOTLESS.
Test of pilotless airplane at Etampes; by
J. J. Ide. May 12, 1n3. 2 p. Photographs.
POTEZ.
Description of Potez tri-motored com­mercial
airplane, type 22. M. I. D. France.
Aug. 3, 1923. 1 p. Photostated dra.wings.
SESEFSKY.
Report on Sesefsky two-seater biplane ; tr.
by J . Vanier from Les Niles, Sept. 10, 1923.
Technical Data Section. Memo. report No.
83. Oct. 9, 1923. 2 p. Photostats .
SPORT, ETC.
Description of Mark sport monoplane,
Sport and Small R 111 22, Caspar Ul sea­plane
and Fokker seaplane; tr. from Illus­teierte
Flugwoche, Mar. 6, 1923. M. I. D.
Germany. July 17, 1923. 7 p .
SPAD.
Brief description of Instrument board on
Spad Cl. M. I. D. France. Aug. 9, 1923.
1 p. Photostated drawings.
AIRCRAFT.
(Lighter-than-Air)
Airship mooring; by Col. Crocco. M. I.
D. Italy. Aug. 13, 1923. 5 p.
Report on gasoline tank release system
for ZR-1; by N. S. Otey. Testing Division.
Naval Aircraft Factory. Test 11T22-10.
Aug. 1. 1923. 2 p . Diag.
Waterproofing for silk cord for free bal­loon
net; by H. I. Hoot. Special Testing
Div ision. Naval Aircraft Factory. Aug. 13,
1923. 4 p.
Test of four-finger patch from Airships
Incorporated. Material Section. McCook Field.
Aug. 20, 1923. 2 p .
D52.6/8
Aeromarine
D52.1/14
Avro
D52.6/2
C. A. M. S.
D52.1/61
DeH-4
D52.1/l
DeMarcay
D52.l / 1
D. T.-1
D52.6 / 1
DT-4
D52.1/30
Farman
D52.1 /27
Farman
D52.6 /1
Huff-Daland
D52.6/4
Nieuport
Macchi
D52.1/135
D52.1 /9
Potez
D52.1 /1
Sesefsky
Al0/223
Dl3.1/81
D52.77 /12
D52.44/145
Dl0/142
DlO /135
1
l
l
f f
f
l
J
!
NEW BOOKS AND DOCUMENTS
EQUIPMENT.
Apparatus for making maps from airplane
photographs; by lNAG process. Inter­national
Aerogeodetic Company. M. I. D.
Germany. July 17, 1923 . 16 p. Photostats.
lmpulr e electric motor for driving record­ing
in struments ;by W. F. Joachim. From
Journal o.L Franklin In~titute. National Ad­visory
Committee for Aeronautics. Technical
Note No. 157. Sept., 1923. 13 p. Photo­graphs,
charts, drawings.
Instrument for recording po::ition
plane control surfaces; by K. M.
Nation.al Advisory Committee for
nautics. Technical Note No. 154.
1923. 4 pp. Photographs.
of air­Ronan.
Aero­Aug.,
Price lh:-t for Dashwood and Partners on
pyrotechnics for aviation. M. I. D. Eng-.
!2nd. July 23, 1923. 6 p.
Catalog on air rectifiers u ::-ed to eliminate
"frozen air" in air brakes. National Safety
·Device and Manufacturing Co. n. d. 12 p.
Illus.
Calibrat:on of two relative air speed indi­cator.:,
built by American T axameter Com­pany;
by E. N. Fales. Wind Tunnel te . t
No. 596. July 23, 1 ')23. 3 p. Charts .
N. A. C. A. recording tachometer :-.nd
angle of attack recorder; by H. J. E. Reid.
National Advi~ory Committee for Aero­nautics
. Te~hnical Note No. 156. Aug.,
1923. 3 p. Photographs.
Catalog on Holt parachutes , landing light•,
air-depth bombs , parachute flares ~nd train­ing
lights, and mail d:ropp :ng devices. York­shire
Steel Co., Ltd. M. I. D. England.
Aug. 8, 1923. 26 p. Illus., photographs.
Descriptive pamphle".: of corset ga~oline
gauge. In French and Englbh. M. I. D.
France. July 26, 1923. 17 p. Blueprints.
Des criptive booklet on Nivex gasoline
gauge. In French with partial tran l:J.tion.
M. I. D. France. July 19, 1923. 17 p.
Illus.
Contribution to study of physiological
princ~ples upon which are ha ed regulat:on
of appliances for inhaling oxygen at high~
altitude · : by Surgeon Maj. M. Beyne. Apr.,
1 ~22. 21 p.
De cription of Berruet & Pradet distance
reading thermometer for aircraft enginee:- . M.
I. D. France. Aug. 7, 1923. 1 p. Photo­stated
dra,wings.
Description of Fournier aero-thermometer.
M. I. D. France. July 19, 1923. 3 p.
Illus.
Descriptive pamphlet of
roometer, manufactured by
Onenia. M. I. D. France.
5 p. Photos tats.
vapor ther­Eociete
Auto
July 26, 1923.
Re-port on water flow nozzle. Bureau of
Aeronautics . Aug. 2, 1923. Photograph,
chart, drawing.
FUELS AND LUBRICANTS.
Effect of Lubac anti-knock compound on
some of repre 3entative material.3 of fuel
system. Material Sect ion. McCook Field.
Sept. 21, 1923. 3 p. Photographs.
Used oil from Rockwell air intermediate
depot bv A. C. Zimmerman. Material bec­tion.
McCook Field. 2 p.
MATERIALS.
BrL:.ish standard specifications for aircraft
materials and components. British Engineer­ing
Standard Ast ociation. 2 vols. July l,
1923.
Compari· en of physical characteris'tbs of
springs manufactured by W . D. Gibson &
Company front annealed wire, subsequently
heat-treated, with tho -5e of springs forrr.ed
from cold drawn wire. Material Section.
McCook Field. Aug. 9, 1 ")23. 2 p.
Compari on of piston porosity tec: t
methods and piston material. Navy Dept.
Bu1·eau of Aeronautics. July 16, 1923. 3
p. Drawing.
D62.4 /24
D52.41 /11 7
D13.3/1
Control Posi­tion
Recorder
D13.4~/4
Dl2.3/2
D13.3/47
Air Speed
Indicators
D13.3/72
Mic.
D52.439 /4
D13.3/2
Ga<:" oline
Gauge
D13.3 /3
Gasoline
Gauge
Dll.331/8
D13.3/20
Thermometer
Dl3.3/19
Thermometer
"13 .3 / 0 1
Thermometer
D13.3/6
Nozzles
Dl 1.3 /78
Dl 1.21 /01
I'·" 0.15 / 16
Mic.
D52.30/128 ·
D52.419 /281
Investigation of foreign substance which
clogged fue] strainer used in endurance flight
at Rockwell air intermediate depot, Coron­ado,
California. Material Section, J4cCook
Field. Sept. 7, 1923. 3 p. Photographs.
Te<::.t of cleaning compounds for metals ;
by H. I. Hoot. Testing division. Naval
Aircraft Factory. Test 6C23-5. Aug. 9,
1923. 2 p.
Characteristics of electric welds made by
Boeing Airplane Company. Material Section.
McCook Field. Oct. 6, 1923. 2 p. Photo­graphs.
COATINGS, PAINTS, ETC.
Investigation to determine suitability of
Paravar as coating for use on aircraft ma­terial.
Material Section. McCook Field.
Aug. 30, 1923. 3 p. Charts.
Effect of one to three coats of solution of
paraffin in benzol on durability of balloon
f a brics. Material Section. McCook Field.
Aug. 22, 1~23. 16 p. Charts.
Efficiency of protective coating applied by
Consolidated Aircraft Corporation to interior
of fuselage tubing of TW -3 type airplanes;
by A. C. Zimmerman. 2 p.
DURAi.UMiN, ALUMINUM ALLOYS, ETC.
Test on cleaning of duralumin, to deter­mine
effect of 10 per cent solution of nitric
acid upon tensile strength. Chemical Lab­oratory.
Naval Aircraft Factory. June 15,
1922. 1 p. .
Report on improperly heat treated dura­lumin
rivets for fleet airship ZR-1; by H. I.
Hoot. Special Testing Division. Naval Air­crdt
Factory. Aug. l , 1923. 3 p.
Test to determine effect of removing sur­face
of "skin" on ten ~ile strength and duc­tility
of Eome aluminum casting alloys. Ma­terial
Section. McCook Field. Aug. 24.
1923. 4 p. Photographs.
Test to determine effect of 10 per cent
solution of nitric acid on auralumin. This
include3 its cleaning action, harmful effects,
and whether acid attacks only tarnis h, or
d issolves metal itself; by G. B. Cook.
Chemical Laboratory. Naval Aircraft Fac­tocy.
Oct. 16, 1922. 4 p.
Effect of quenching temperature upon
phys ical propertie • of ca!3. t aluminum-cop­per-
magne ium alloys. Material Section,
McCook Field. Sept. 20, 1923. 10 p. Charts.
Corrosion of aluminum gas tanks due to
rawhide strapJ . Navy Dept. Bureau of
Aeronautics. Technical order No. 34. Oct.
3, 1923. 2 p.
Tes t of aluminum al1oys, "Martin metal,"
cas tings and sheet by H. C. Knerr. Metal­lurgical
laboratory. Naval aircraft factory.
July 25, 1923. 7 p. Photographs.
Effects of over-heating and repeated melt­ing
op aluminum; by W,. Ro-.J enhain and J. D.
Grogan. Aeronautic2.l Research Committee.
Reports and memoranda No. 783. May, 1922.
11 p. Charts.
Influence of calcium and of calcium plus
silicon on aluminum, by J. D. Grogan. Aero­nautical
Research Committee. Reports and
Meir.oranda No. 832. (M. 12). May, 1')22.
7 p. Illus. charts.
Chemical, metallographic, and physical
properties of three grades of agrite bearing
metal, s ubmitted by American Injector Com­pany.
Material Section. MeCook Field.
Oct. 10, 1923 . 2 p. Photographs.
BABBITT.
Babbitting direct to case hardened steel,
describing method used in babbitting shOe.:i
for truss bearings of Almen engine. Ma­terial
Section. McCook Field. Aug. 31,
1923. 2 p. Photographs.
BOUSCH STONE BEARING.
Report on Bousch Ftone bearing;
J. Vanier. Technical Data Section.
report No. 84. Oct. 22, 1923. 2 'iJ.
stat, chart.
tr. by
Memo.
Photo-
33
A60.1/16
D50.l /6
D00.57 /18
Dl 1.22 /31
D24.32/40
Dl 1.23 /172
Dl0.13/142
D52.39 /133
Dl0.13 /143
Dl0.13 /141
DI 0.13 /144
D52.44 / 146
Dl0.13/145
D00.12
R. & M./783
D00.12 /832
R. & M.
Dl0.16 /21
D00.57 /17
D52.419 /285
34, TECH N I CAL BU L-L E T I N No. 36
BRONZE.
P h y s ical, c la s sical. and m etallog raphic
properties of a n on-gran bron ze , m a n ufa c ­tu
red by F e deral Bearing a n d B us h in g Cor­po:
·ation . Mat e r ia l Section . McCook Fie ld .
Oct. l;l, 1923. 5 p . P h otograph s .
TUC-TUR MET AL.
I nve s tigation of p roperties of t uc- tu r
m e ta l ; by H . C. K n err. Me ta ll urg ical S e c ­t
ion: Nava l Aire-ra f t Factory. J u ly 30,
19 23. 4 p. P hotogr aph s, c hart.
STEEL.
Effect of a tem perature of 212 ° F . on
s t eel s ubmit ted to a lt e r n ating t ort ion: by
W. Ma son. Aerona utica l R e s earch Com­m
itte.e . , R epo rts . and Mem o r a nda N'o. 8 63 .
F e h ., ··l.923 . 12 p, Charts, diag.
I nvar and re lated nickel s t e e l~. Burea u
of Standards. Circular No. 58. E d. 2. J une
2 2 , 1~23. 93 p . drawings, p hot og r a p h s ,
c h a rts .
FABRIC.
U e of t hree -plv f a b r ic to r eplace two-9 lv
f a bric in observat ion a i r s h ip ~uch a s U. S.
M. B. Materia l S e ction. McCook F ie ld.
Aug . 17, 1 9 23. 2 p. Cha rts .
MICA.
P r opert ies and u f e~ of m ica . M. I. D.
Eng l:md. Aug. r :i, 1923. 5 p .
RUBBER.
l ti.v es t ig a tion to d etermine a m ore s u it a b le
r ubber compou nd for s hock ab- orber cord.
Ma t e r ial Sectic,T\. McCook F iel d . A ug. 23,
19? 3. 5 p, Ch a r ts .
Te3t of gas oli n e - res is tan t h os e. Mate r ia l
~ection. McCook · Field . Aug . 31 , 1923 .
2 p . ,'
' L'es t of ga- o line re - is t 2.n ce h o - e m a n ufac­tured
by In d us tria l Rubber P rodu cts , Ltd.
Ma teria l Se c tion. McCcok , Field. Aug. 3 1,
1 9 2 3 . 2 p.
WIRE.
Tes t to dete rm in e fa il ure of s t ream li ne
wires b y H . C. Kne rr . Metallurgica l L a b o r a ­tory
, N aval A ircra ft F a ctory . Te :t 8M 23 -3.
Aug . 28, 1923 . 8 p. P hotog raphs , d ia g s .
S tream line w ire :fa ilu r ~s at bra c:.s t a gs ; b y
H. D. Kner r , M el a ll ll r g ical Laboratory .
Na val Aircra f t Factory, T e s t 7M23 -l. Aug.
3 1, 1 9 23. 3 p, P h otog rap h s .
WOOD.
Strength properties of minol" parts of ex­p
e rimental wooden box beamc:. . Mate ria l S ec ­t
io n . McCook F ie ld. Oct. 18, 1 923 . 3 p,
. POWER PL'ANTS.
Arit hme t ic of d is trib u t ion in m u lti ­cy
lin der eng ines ; by S . W . Sp a r r ow.. Na­t
ional Advfrory Committee f6r A e ronaut.i'c !:' .
Tec hnical notes No. 1 6 2.. Oct ., 1:)2 3 . 9 p,
Ch arts .
Di.:5 cuss ion of "pros " and " cons " of sin g le
and do u b le row a ir -cooled r a dia l e ngines .
Powi,r P la nt S ectio n . McCook F ie ld. Aug.
1 8, 1 923 . 4 p,
Eng ine p e r f orm ance a n d dete rmin a t ion of
ab· ol ute ceilin g ; by W. S . Dieh l. Natio n a l
Advi ory Committee fo r Aero n a u tic s . Re­port
No. 1 71. 1923. 12 p . Ch a rts:
Air res is t a nce o:f valve mech a n i sm s on t wo
a ir-coo led c y linders ; by E. N. Fale -::. . W in d
Tun n e l t est. McCook F ield. J u ne 2 1, 192 3 .
So~e problems of f>ta t ic radia l air-cooled
a e ro eng in e s ; by A. H . R. F edden. In t e r ­nnt
iona l A ir Cong ress . . LonC.on. J un e 27,
192 3. 5 p, Ch arts .
Ita lia n engine data c ha r t . Ma r ., 1 9 23 .
GARUFFA.
Des c ription of Ga.r uffa engine . In Italian
a n d E ng lis h . M . I . D . Ita ly . Jun e 27,
1923 . 4 p . Photog,aph, drawin g s . i
JUPITER.
Replies to Ques t ionnaire in reg a rd to
J upiter air-cooled engine. J a n uary 2}J , 1923.
2 p. .
Chemical and m etallog r aphic c h aracter h ­tiCS
of c y lin'der materia.l us ed in J upiter. ,
e ngine. Mate r ia l Sect io n . McCook Field. ~
S e pt. 28, 1 9 23 . 2 )). P hotog·r a p h .
Dl0.1 6 / 20
D 1 0. l / 92
D 00.1 2 / 863
R . & M.
Dl0.11 /96
Ed. 2
D~4.3/90
D l 0.21 / 6
D 52.55/25
D l 0 / 138
Dl0 /1 3 3
D l0 / 141
Dl 0 / 1 40
D52.3 3 l / 101
,D 52.41/ 1 20
D5 2 .4 l / 23
D 52.41 / 11 8
D 5 2.419 / 240
D 5 2.4 1 / 11 4
f\ 52.41/4
M.i c.
I talian
D52.41 / 3
Ga ruffa
D52.41 / 16
Bri s t ol
D52..4 l 7 / 1 3.
LAWRANCE.
Limiting r. p. m . of L a wrance J -1 e n g in e .
Na.v v Dept. Bureau of Aeronau tics . Tech­n
ical Order N o. 3 2 . Sept. 21 , 1 9 23. 1 p .
LIBERTY.
Tes t t o de te:·m in e whe t her m a teria l and
h eat t r ea~m e n t in Libertv f!' ener2.tor d rivin!!
s haft g ear were in ar:corda n <'e with rH1uire ­m
e nts of d r awing No. 0 4776 7. Mater ia l
Sect ion . McCook Fie ld. Oct. 5, 192 3. 3 p.
Dr :iw ing .
Tes t to determine cau - e of fa il ure c r~.nk­,.
ase b ea ring bolt s f rom Liberty " 12" e n g in e .
Ma t eria l Se ctio n . McCook Fie ld. S ept. 7,
1 9 23 . 2 p . P h otogra p h s .
Develoom ent of dx- lobe Liberty f t a rting
dog s . Navy D ept. Bureau of A ero n autic s .
Aug. 6, 1 923. 4 p . D ia g s .
PACKARD.
In- t a lla tion . inspe ct :on and rnainten 2n ce
of Packa rd lA1 551 a ircraft en g in e , prepared
e c-pec ia llv for tr e on fl eet a irs h ip No. I ,
ZR-1. Packar d Motor Ca r Compa n y . Aug .,
192 3. 12 p. D rawings .
W - 1.
Scor ing of b ear ings a nd journ·a b durin g
f-ndur2 n ce te:;t of W -1 en•.:d n e. Ma teria l
Sec t ion. McCook F ie ld. Se pt, 29, 192 3.
2 p .
WRIG!-!T.
T e s t of h ig h speed s t eel for v a lve ".ior r e ­de
~ig ned W r ig h t r a dia l eng in e . l\:1 a te:.·ia l
Section . McCook F ie ld. ' Cct. 18, 1 923. 2 p.
CARBURETORS.
DeP-c ription of LeGr2.in carbu reto r; tr.
T echn ica l Data Section . Me rr.o . repo!'t No.
77. S ept. 8, 023 . 2 p . P hotos t a ted draw-in
g s .
In,. truction c; fo r in s t a llation, operation,
operat !on, ma in t e n a n ce and reprdr of S trom ­h
erg NA-U6 ca r b uretor f or W rig h t mode l
"H" eng in e ~. Air Serv ice Eng in e er ing
Di vi ion . Aug- ., 1923 . 16 p . Illu s ., dra w-in
g s .
ln3t ru ctions for u ~e a nd a djus tm e n t of
St rom b e rg NA-S4 carbure t o rs on Lawr::t n ce
radia l a ir cooled eng in e . 1923 . 5 p . I I1u s .
FUEL SYSTEM,
Tim lag a nd in terval of di .... c h a rge with
r p r ing a ctua ted fue l inject ion pump ; by
R obertFon Matt hews a'.nd A. W . Gar diner.
N a t io n a l Ad vic:- ory Committee for Ae ro - ·
n a utics . T echnica l ·nqtes N o . 15 9 . S ept.,
1923 . 16 p. Cha rt .
!GNITION AND STARTING.
E xpe r imen t 2 I b a t tery coil r tarting s y s t em .
Na vv Dept. B u~ea u of Aeron autic - . J uly
2 1 , 1923. 8 p, P h o t og r a p hs, drawin g.
In: truction> concerni ng fit t ing- of n ew
co ntact b r eaker a rm on W atfor d C 6 m ag­n
e tos . Not ice to g round e n f! '! n ee rR No. 1.
year 1923. Air Minis try. Ju ly 1 7, 1 923 .
1 p .
PROPELLERS.
S y s t em atic exper im ent ; with a ir !:crew
models; b y IC S c h affrau. M. I. D. Germany .
J u ly 11 , 1 ~2 3. 88 p . D r a win gs .
Ccn t en ... s :
P t . 1-1. E x perimen "'.'s of Dur a nd
and Les lie; a t Lela nd
Sta n fo r d Junior Unive rs ­ity
.
P t . '.!-2. Experiment3 of Sc haffrau
in P r uRe: ian l nRt itute fo r
H y draulic a n d Nava l En­gineer
ing.
Pt. 2-1. Computa tion of r e - ults
of Bra mw,e'lls mo:le l pro­p
e ller · tes t s .
Analy d -, of Dr . Sch r- ff r a u 's propele r m o:lel
t e s t s :b y 111. M. Mu nk . N a cion a l Advi sory
r.omm. it tee for A'"'!'Op.a u t ics .v. T ec h n ical note
No. 1 58 . Se pt., 1923. 5 P-_., Ch a rts .
_RADIO.
Wor k b eing don e a t Il ureau of S t anda rd·s
ori t ·cil m is ~ion of r a d io Eig n aL; of sta ndard
f r e q u ency; r peciftca tion s for CY..lin d r ica l , <l rY
ce ll s , etc. Sept . 1 5, 192 3. 11 p .
D52.41 /7
Lawran ce
D52.41 / 124
L iberty
D52.419 /280
D52 .41 5/17
D 52.41 / 40
P ackard
D 52 .4 1 / 4
W-1
Ji 52.4 19 ; 28
D5 2 .4 11 / 130
D 5 2 .411 / 13l
D 52 .41 / 6
L awrance
D 5 2.4 1 / 119
D5 2.4 1 5 / 18
D 00 .12 / 95,
192 3 -No. 1
J:·52 .4 3 / 43...,8.
:C-52.4 3/40
i·,·
D00.12 / 77
T . N. B .,·