In view of the rapid progress in military aeronautics, the necessity

for the development of a high-powered motor adaptable to American

methods of quantity production was early recognized. The result of

the efforts to meet this need was the Liberty motor—America’s chief

contribution to aviation, and one of the great achievements of the

war. After this motor emerged from the experimental stage, production

increased with great rapidity, the October output reaching 4,200, or

nearly one-third of the total production up to the signing of the

armistice. The factories engaged in the manufacture of this motor, and

their total production to November 8, are listed in Table 21.

Table 21.—Production of Liberty motor to November 8, 1918, by

factories:

Packard Motor Car Co. 4,654

Lincoln Motor Corporation 3,720

Ford Motor Corporation 3,025

General Motors Corporation 1,554

Nordyke & Marmon Co. 433

—————

Total 13,386

Of this total, 9,834 were high-compression, or army type, and 3,572

low-compression, or navy type, the latter being used in seaplanes and

large night bombers.

In addition to those installed in planes, about 3,500 Liberty engines

were shipped overseas, to be used as spares and for delivery to the

Allies.

Other types of service engines, including the Hispano-Suiza 300 h. p.,

the Bugatti, and the Liberty 8-cylinder, were under development when

hostilities ceased. The Hispano-Suiza 180 h. p. had already reached

quantity production. Nearly 500 engines of this type were produced,

about half of which were shipped to France and England for use in

foreign-built pursuit planes.

Table 22 gives a résumé of the production of service engines by

quarterly periods:

Table 22.—Production of service engines in 1918.

Jan. 1 to Apr. 1 to July 1 to Oct. 1 to

Name of engine Mar. 31 June 30 Sept. 30 Nov. 8 Total

Liberty 12, Army 122 1,493 4,116 4,093 9,824

Liberty 12, Navy 142 633 1,710 1,087 3,572

Hispano-Suiza 180

h. p. ... ... 185 284 469

IMPROVEMENT IN INSTRUMENTS AND ACCESSORIES

Few facilities existed for the manufacture of many of the delicate

instruments and intricate mechanisms going into the equipment of every

battle-plane. The courage and determination with which these most

difficult problems were met and solved will form one of the bright

pages in the archives of American industry.

One of the most important outgrowths of the research work which the

war stimulated was the development of voice command in formation

flying by means of wireless devices. The great significance of this

invention will be appreciated when it is realized that the leader of

a formation has heretofore been dependent on signals for conveying

instructions to the individual units of the squadron.

TRAINING OF PERSONNEL

After the declaration of war the construction of training fields

proceeded with such rapidity that the demand for training equipment

greatly exceeded the output. Since the latter part of 1917, however,

the supply of elementary training planes and engines has been more

than sufficient to meet the demands, while the situation as regards

certain types of planes for advanced training has greatly improved.

Approximately 17,000 cadets were graduated from ground schools; 8,602

reserve military aviators were graduated from elementary training

schools; and 4,028 aviators completed the course in advanced training

provided in this country. Pending the provision of adequate equipment

for specialized advanced training, the policy was adopted of sending

students overseas for a short finishing course before going into

action. The shortage of skilled mechanics with sufficient knowledge of

aeroplanes and motors was met by the establishment of training schools

from which over 14,000 mechanics were graduated.

At the cessation of hostilities there were in training as aviators

in the United States 6,528 men, of whom 22 per cent were in ground

schools, 37 per cent in elementary schools, and 41 per cent in

advanced training schools. The number of men in training as aviator

mechanics was 2,154.

FORCES AT THE FRONT

Early in 1918 the first squadrons composed of American personnel

provided with French planes appeared at the front. The number was

increased as rapidly as equipment could be obtained. On September 30,

the date of the latest available information, there were 32 squadrons

at the front; of these 15 were pursuit, 13 observation, and 4 bombing.

The first squadron equipped with American planes reached the front in

the latter part of July.

LOSSES IN BATTLE AND IN TRAINING

Though the casualties in the air force were small as compared with the

total strength, the casualty rate of the flying personnel at the front

was somewhat above the artillery and infantry rates. The reported

battle fatalities up to October 24 were 128 and accident fatalities

overseas 244. The results of Allied and American experience at the

front indicate that two aviators lose their lives in accidents for

each aviator killed in battle. The fatalities at training fields in

the United States to October 24th were 262.

[A later official report gave the total U. S. aviators lost in combat

as 171, and those killed by accident as 554.]

COMMISSIONED AND ENLISTED STRENGTH

On America’s entrance into the war, the personnel of the Air Service

consisted of 65 officers and 1,120 men. When the armistice was signed

the total strength was slightly over 190,000, comprising about 20,000

commissioned officers, over 6,000 cadets under training, and 164,000

enlisted men. In addition to the cadets under training, the flying

personnel was composed of about 11,000 officers, of whom approximately

42 per cent were with the Expeditionary Force when hostilities ceased.

The Air Service constituted slightly over 5 per cent of the total

strength of the Army.

GENERAL PERSHING’S REPORT

Secretary Baker’s report included a communication received from General

Pershing in which he commented on aircraft and the Air Service as

follows:

“Our entry into the war found us with few of the auxiliaries necessary

for its conduct in the modern sense. Among our most important

deficiencies in material were artillery, aviation, and tanks. In order

to meet our requirements as rapidly as possible, we accepted the offer

of the French Government to provide us with the necessary artillery

equipment.

“In aviation we were in the same situation, and here again the French

Government came to our aid until our own aviation program should

be under way. We obtained from the French the necessary planes for

training our personnel, and they have provided us with a total of

2,676 pursuit, observation, and bombing planes. The first aeroplanes

received from home arrived in May, and altogether we have received

1,379. The first American squadron completely equipped by American

production, including aeroplanes, crossed the German lines on August

7, 1918.

“It should be fully realized that the French Government has always

taken a most liberal attitude and has been most anxious to give us

every possible assistance in meeting our deficiencies in these as

well as in other respects. Our dependence upon France for artillery,

aviation, and tanks was, of course, due to the fact that our

industries had not been exclusively devoted to military production.

All credit is due our own manufacturers for their efforts to meet our

requirements, as at the time the armistice was signed we were able to

look forward to the early supply of practically all our necessities

from our own factories.”

THE HUGHES REPORT

The committee appointed by the President to investigate the charges of

misappropriation of funds reported in November, 1918, on the number of

training planes and engines built. Justice Chas. E. Hughes was chairman

of the committee:

AEROPLANES AND ENGINES DELIVERED DURING FISCAL YEAR ENDING JUNE 30,

1918

The reported deliveries of Aeroplanes and Engines made prior to June

30, 1918, are as follows:

AEROPLANES

Elementary Training Planes

JN4-D 2972

SJ-1 1600

—— 4572

Advanced Training Planes

JN4-H

Training 402

Gunnery 321

JN6-HB 100

S4-B 100

S4-C 73

Penguin 50

—— 1046

Combat and Bombing Planes

DeH-4 529

Bristol Fighter 24

—— 553

——

Total planes 6171

ENGINES

Elementary Training

OX-5 5474

A7a 2188

—— 7662

Advanced Training

Hispano 150 H. P. 2188

Gnome 100 ” 209

Le Rhone 80 ” 68

Lawrence 28 ” 114

—— 2579

Combat and Bombing

U. S. 12 Cylinder (Army Type) 1615

U. S. 12 Cylinder (Navy Type) 775

Hispano 300 H. P. 2

———— 2392

TOTAL ENGINES = 12633

NUMBER OF MACHINES AT THE FRONT

Report prepared by Statistics Branch, General Staff, War Department,

March 22, 1919, concerning the 628 De Haviland 4 planes put in service

at front before armistice.

The following table and diagram shows the status of production,

shipments and use overseas of De Haviland 4 service planes at the date

of the armistice:

Per cent

of total

Number production

Produced 3,227 100

Floated 1,885 58

Received at French ports (_a_) 1,185 37

Assembled overseas 1,025 32

Put into service overseas 983 30

Put into service at front 628 19

In commission at front (_b_) 457 14

(_a_) To November 1, 1918.

(_b_) November 3, 1918.

Value of contracts cancelled and suspended exceed $480,000,000.

The following is a summary of the value of cancellations and

suspensions of contracts to March 19, 1919:

Per cent

Value of total

Engines and spare parts $250,409,982 52

Airplanes and spare parts 167,554,386 35

Chemicals and chemical plants 19,852,370 4

Instruments and accessories 13,832,902 3

Balloons and supplies 10,071,035 2

Fabrics, lumber and metals 7,968,324 2

Miscellaneous 11,041,132 2

————————

Total $480,730,131

THE SIXTY-FOUR AMERICAN ACES

The following official list gives the status of the sixty-four American

aces—that is, aviators who had each downed five or more enemies by the

time hostilities ceased:

Captain Edward V. Rickenbacker of Columbus, Ohio, famous as an

automobile driver, was the premier “Ace” of the American air force in

France, having twenty-six enemy planes to his credit.

First Lieutenant Frank Luke, Jr., of Phœnix, Ariz., who was killed in

action May 19, 1918, was second on the list of “Aces,” with eighteen

victories to his credit, and Major Victor Raoul Lufbery of Wallingford,

Conn., also killed in action May 19, 1918, was third, with seventeen

victories. Before joining the American Army, Major Lufbery was a member

of the Lafayette Escadrille.

Captain Reed G. Landis of Chicago, son of Judge Landis, and First

Lieutenant David E. Putnam, of Brookline, Mass., who was killed in

action, had twelve victories each. The other “Aces,” with the number of

victories credited to each, follow:

First Lieutenant Fields Kinley, Gravette, Ark., 10.

First Lieutenant G. A. Vaughn, Jr., 341 Washington Avenue, Brooklyn, 10.

First Lieutenant J. M. Swaab, Philadelphia, 10.

First Lieutenant T. G. Cassady, 9.

First Lieutenant C. E. Wright, Cambridge, Mass., 9.

First Lieutenant W. P. Erwin, Chicago, 9.

Captain E. W. Springs, Lancaster, Penn., 9.

First Lieutenant H. R. Clay, Jr., Fort Worth, Texas, 8.

Major J. A. Meissner, 45 Lenox Road, Brooklyn, N. Y., 8.

Captain Hamilton Coolidge (deceased), Boston, Mass., 8.

Captain G. De F. Larner, Washington, D. C., 8.

First Lieutenant P. F. Baer, Fort Wayne, Ind., 8 (captured May 22, 1918).

First Lieutenant F. O. D. Hunter, Savannah, Ga., 8.

First Lieutenant W. W. White, 541 Lexington Avenue, New York City, 8.

Second Lieutenant Clinton Jones, San Francisco, Cal., 8.

Captain R. M. Chambers, Memphis, Tenn., 7.

First Lieutenant Harvey Cook, Toledo, Ohio, 7.

First Lieutenant L. C. Holden, 103 Park Avenue, New York City, 7.

First Lieutenant K. H. Schoen (deceased), Indianapolis, Ind., 7.

First Lieutenant W. A. Robertson, Fort Smith, Ark., 7.

First Lieutenant L. J. Rummell, 798 South 11th Street, Newark, N. J., 7.

First Lieutenant L. A. Hamilton (deceased), Burlington, Vt., or

Pittsfield, Mass., 7.

First Lieutenant J. O. Creech, Washington, D. C., 6.

Second Lieutenant Howard Burdick, 175 Remsen Street, Brooklyn, N. Y., 6.

First Lieutenant C. L. Bissell, Kane, Penn., 6.

Major H. E. Hartney, Saskatoon, Canada, 6.

Captain Douglass Campbell, Mount Hamilton, Cal., 6.

Captain J. C. Vasconcelles, Denver, Col., 6.

Captain E. G. Tobin, San Antonio, Texas, 6.

First Lieutenant E. P. Curtis, Rochester, N. Y., 6.

First Lieutenant Sumner Sewell, no address, 6.

First Lieutenant R. A. O’Neill, Nogales, Ariz., 6.

First Lieutenant Donald Hudson, Kansas City, Mo., 6.

First Lieutenant M. K. Guthrie, Mobile, Ala., 6.

First Lieutenant W. H. Stovall, Stovall, Miss., 6.

First Lieutenant J. D. Beane (missing in action), 6.

First Lieutenant A. R. Brooks, Framingham, Mass., 6.

First Lieutenant R. O. Lindsay, Madison, N. C., 6.

First Lieutenant Martinus Stenseth, Twin City, Minn., 6.

Second Lieutenant F. K. Hays, Chicago, Ill., 6.

First Lieutenant H. C. Klotts, no address, 5.

Lieutenant-Colonel William Thaw, Pittsburgh, Penn., 5.

Major D. McK. Peterson, Honesdale, Penn., 5.

Captain H. R. Buckley, Agawam, Mass., 5.

Major C. J. Biddle, Philadelphia, Penn., 5.

First Lieutenant James Knowles, Cambridge, Mass., 5.

First Lieutenant J. A. Healey, Jersey City, N. J., 5.

First Lieutenant Innis Potter, no address, 5.

First Lieutenant F. M. Symonds, 20 West 8th Street, New York City, 5.

First Lieutenant J. F. Wehner (deceased), 124 East 28th Street,

New York, 5.

First Lieutenant J. J. Sereley, Chicago, 5.

First Lieutenant E. M. Haight, Astoria, N. Y., 5.

First Lieutenant H. H. George, Niagara Falls, N. Y., 5.

First Lieutenant G. W. Furlow, Rochester, Minn., 5.

First Lieutenant A. E. Esterbrook, Fort Flagler, Wash., 5.

First Lieutenant B. V. Baucom, Milford, Texas, 5.

Second Lieutenant Harold McArthur, no address, 5.

Second Lieutenant J. S. Owens, Baltimore, 5.

Second Lieutenant J. O. Donaldson, Washington, D. C., 5.

OTHER AMERICANS WHO ARE CREDITED WITH BRINGING DOWN ONE OR MORE PLANES

Lieutenant Frank L. Baylies, New Bedford, Mass. (killed June 20, 1918,

in the British Air Service), 12.

Adjutant E. C. Parsons, Springfield, Mass., 4.

Lieutenant H. Clay Ferguson, wounded March 12, 1918, 4.

Captain J. Norman Hall, Lafayette Escadrille and A. E. F., Colfax, Ia.,

wounded and captured, May 7, 1918, 4.

Lieutenant Joseph C. Stehlin, Lafayette Escadrille, Brooklyn, N. Y., 3.

Lieutenant Norman Prince (organizer of Lafayette Escadrille),

Beverly Farms, Mass., killed October 15, 1916, 3.

Lieutenant Kiffin Yates Rockwell, Lafayette Escadrille, Asheville, N.C.,

killed September 23, 1916, 4.

Lieutenant Walter Rheno, Martha’s Vineyard, Mass., 3.

Lieutenant Walter Lovell, Lafayette Escadrille, Concord, Mass., 3.

Lieutenant Thomas Hitchcock, Jr., Lafayette Escadrille, Roslyn, N. Y.,

captured March 10, 1918. He escaped later. 3.

Lieutenant Bert Hall, Lafayette Escadrille, Bowling Green, Ky., retired

December, 1916, 3.

George Turnure, Lenox, Mass., third on July 17, 1918, 3.

Lieutenant Hugh Dugan, Chicago, Royal Flying Corps, captured

April 6, 1918, 2.

Lieutenant G. de Freest Larner, Washington, D. C., 2.

Lieutenant Andrew C. Campbell, Chicago, missing, 2.

Captain Phelps Collins, Detroit, killed March 18, 1918, 2.

Lieutenant Didier Masson, New York, Lafayette Escadrille, 2.

Christopher Ford, New York, 2.

Lieutenant W. A. Wellman, Cambridge, Mass., 2.

Sergeant James E. Connelly, Philadelphia, Pa., 2.

Sergeant Victor Chapman, Lafayette Escadrille, killed June 23, 1916, 2.

Sergeant Vernon Booth, Chicago, 2.

Sergeant Austin B. Crehore, Westfield, New York, 1.

Lieutenant Willis Haviland, Minneapolis, Minn., 1.

Lieutenant Harry Sweet Jones, Hartford, Pa., 1.

Lieutenant Charles C. Johnson, St. Louis, Mo., 1.

Captain Robert L. Rockwell, Cincinnati, Ohio, 1.

Lieutenant Stuart Walcott, Washington, killed December 14, 1917, 1.

Lieutenant Alan F. Winslow, Rive Forest, Ill., 1.

Lieutenant Edgar Tobin, San Antonio, on July 11, 1918, 1.

Lieutenant Charles T. Merrick, Eldora, Iowa, 1.

Lieutenant Alexander O. Craig, New York, in Italy, on July 5, 1918, 1.

Lieutenant Sumner Sewell, Bath, Me., above Toul, on June 3, 1918, 1.

Lieutenant William J. Hoover, Hartsville, S. C., on July 2, 1918, 1.

Lieutenant Alfred A. Grant, Denton, Texas, on July 2, 1918, 1.

Lieutenant John McArthur, Buffalo, N. Y., on July 2, 1918, 1.

Lieutenant Tyler Cook Bronson, New York, on July 1, 1918, 1.

Lieutenant Charles W. Chapman on May 8, 1918. Both he and victim

fell in flames, 1.

Captain Kenneth Marr, on May 15, 1918, 1.

Lieutenant Henry Grendelass, 1.

Lieutenant Edward Buford, Jr., Nashville, Tenn., on May 22, 1918, 1.

Lieutenant William H. Taylor, New York, on May 21, 1918, 1.

Ensign Stephen Potter, Boston, Mass., killed April 25, 1918, 1.

Lieutenant Walter Avery, Columbus, Ohio, brought down and captured

Captain Menckhoff, the German ace, who had 34 victories on

July 25, 1918, 1.

CITATIONS AND DECORATIONS OF MEMBERS OF THE U. S. ARMY AIR SERVICE

DISTINGUISHED SERVICE CROSS

Gardner Philip Allen, First Lieutenant, C. A. C.

Flynn L. A. Andrew, First Lieutenant.

David H. Backus, First Lieutenant.

Herbert B. Bartholf, First Lieutenant.

Erwin R. Bleckley, Second Lieutenant.

Samuel C. Bowman, Second Lieutenant.

Hugh D. G. Broomfield, First Lieutenant.

John R. Castleman, First Lieutenant.

Weir H. Cook, First Lieutenant.

Hamilton Coolidge (deceased), Captain.

Justin P. Follette, First Lieutenant.

William F. Frank, First Lieutenant.

Harold E. Goettler (deceased), Second Lieutenant.

Andre Gundelach (deceased), First Lieutenant.

D. C. Hunter, First Lieutenant.

John N. Jeffers, First Lieutenant.

Samuel Kaye, Jr., First Lieutenant.

Willburt E. Kinsley, Second Lieutenant.

James Knowles, First Lieutenant.

G. DeFreest Larner, First Lieutenant.

William O. Lowe, Second Lieutenant, U. S. M. C.

Edward Russell Moore, First Lieutenant.

Edward M. Morris, Second Lieutenant.

Stephen H. Noyes, Captain.

Alfred B. Patterson, Jr., First Lieutenant.

Britton Polley, First Lieutenant.

Charles P. Porter, Second Lieutenant.

Clearton H. Reynolds, Captain.

Leslie J. Rummell, First Lieutenant.

Karl J. Schoen (deceased), First Lieutenant.

Richard B. Shelby, First Lieutenant.

John Y. Stokes, Jr., First Lieutenant.

William H. Stovall, First Lieutenant.

William H. Vail, First Lieutenant.

Pennington H. Way (deceased), Second Lieutenant.

Joseph F. Wehner, First Lieutenant.

Chester E. Wright, First Lieutenant.

LEGION OF HONOR—FRENCH

(COMMANDER)

Charles T. Menoher, Major-General.

William Mitchell, Brigadier-General.

CROIX DE GUERRE—FRENCH

Thomas J. Abernathy, Second Lieutenant.

James A. Healy, First Lieutenant.

Arthur H. Jones, First Lieutenant.

Charles T. Menoher, Major-General.

Ralph A. O’Neill, First Lieutenant.

Charles P. Porter, Second Lieutenant.

Kenneth L. Porter, Second Lieutenant.

Joseph C. Raible, Jr., First Lieutenant.

Louis C. Simon, Jr., First Lieutenant.

ITALIAN CITATIONS

James P. Hanley, Jr., First Lieutenant.

George C. Hering, First Lieutenant.

William P. Shelton, First Lieutenant.

Norman Sweetser, First Lieutenant.

Emory E. Watchorn, First Lieutenant.

Frederick K. Weyerhaeuser, First Lieutenant.

FRENCH CITATIONS

Valentine J. Burger, Second Lieutenant.

Alexander T. Grier, Second Lieutenant.

Horace A. Lake, Second Lieutenant.

CROCE AL MERITO DI GUERRA—ITALIAN

James L. Bahl, First Lieutenant.

Raymond P. Baldwin, First Lieutenant.

Arthur M. Beach, First Lieutenant.

Allen W. Bevin, First Lieutenant.

Gilbert P. Bogart, First Lieutenant.

Arthur F. Clement, First Lieutenant.

William G. Cochran, First Lieutenant.

De Witt Coleman, Jr., First Lieutenant.

Kenneth G. Collins, First Lieutenant.

Alexander M. Craig, First Lieutenant.

Herbert C. Dobbs, Jr., First Lieutenant.

Edmund A. Donnan, First Lieutenant.

Norton Downs, Jr., First Lieutenant.

Arthur D. Farquhar, First Lieutenant.

Harry S. Kinkenstaedt, First Lieutenant.

Willis S. Fitch, First Lieutenant.

Donald G. Frost, First Lieutenant.

William O. Frost, First Lieutenant.

James P. Hanley, Jr., First Lieutenant.

Spencer L. Hart, Second Lieutenant.

George C. Hering, First Lieutenant.

Wallace Hoggson, First Lieutenant.

Gosta A. Johnson, First Lieutenant.

James Kennedy, Second Lieutenant.

LeRoy D. Kiley, First Lieutenant.

Herman F. Kreuger, First Lieutenant.

Fiorello H. LaGuardia, Major.

Paton MacGilvary, First Lieutenant.

Oble Mitchell, First Lieutenant.

William H. Potthoff, First Lieutenant.

Aubrey G. Russel, First Lieutenant.

William B. Shelton, First Lieutenant.

Norman Sweetser, First Lieutenant.

Norman Terry, Second Lieutenant.

Emory E. Watchorn, First Lieutenant.

Frederick K. Weyerhaeuser, First Lieutenant.

Warren Wheeler, First Lieutenant.

Alfred S. R. Wilson, First Lieutenant.

Warren S. Wilson, First Lieutenant.

REPORT OF THE DIRECTOR OF MILITARY AERONAUTICS

WAR DEPARTMENT,

OFFICE OF THE DIRECTOR OF MILITARY AERONAUTICS,

_November 3, 1918._

SIR: I have the honor to submit herewith the annual report of the

Division of Military Aeronautics for the fiscal year ended June 30,

1918. Though the Division of Military Aeronautics was created only

on April 24, 1917, it was agreed that the duties intrusted to it and

previously carried out by the Signal Corps should be covered in this

report in order to present a continuous story of the development of the

personnel, training, and organizing phases of the present Air Service.

Also it should be pointed out that operations on the front in France

have been left largely to whatever report the American Expeditionary

Force may deem wise.

The fiscal year 1917-18 saw aviation develop from a wholly subsidiary

branch of the Army as the Aviation Section of the Signal Corps to

a position of extreme and decisive importance as the Air Service,

directly under the Chief of Staff. From the most insignificant

beginnings it came within the year to be one of America’s major efforts

in the war.

This is all the more surprising when America’s previous backwardness

in aviation is considered. This country has stood practically still in

aerial progress, while the war in Europe brought about an extraordinary

advance. From all this the United States was entirely shut off up

to the time it abandoned neutrality. So little exact knowledge was

available that the first American planes to go with the expedition into

Mexico in March, 1916, were all rendered useless in accidents within a

short time of arrival. There was practically no aviation technique here

comparable to Europe’s, almost negligible manufacturing facilities,

not a hundred trained flyers, and only the most rudimentary facilities

for training. Moreover, no one had any adequate appreciation of the

intricacy and skill required in the making of either an aeroplane or

the training of a pilot.

As against this stagnation Europe’s progress in two and one-half years

of war had been tremendous. The first planes to go to the front in 1914

had been few in number, unequipped with radio, machine guns, bombs, or

photographic apparatus, and entirely unproved in military value. Their

extraordinary success, however, in disclosing the size of the German

concentration in Belgium at once brought them into a position of great

importance. Very shortly radio was installed to replace signaling by

dropping tinsel or making curious evolutions; the pistols of the pilots

gave way to machine guns; the easy-going system of dropping bombs over

the side was replaced by regular bombing planes, and the occasional

taking of photographs by an intricate system of picturing every mile of

the front. Engine power increased to 200, 300, 400, 500 horse power;

huge planes with large carrying capacity were being developed for

night-bombing; and operations were taking place by whole squadrons in

various air strata—light, single-seater scouts around 15,000 to 20,000

feet, two-seater day bombers around 9,000 feet, and photographic and

observation planes around 6,000 feet.

In contrast to all this development the United States at the time of

its entry into the war stood very little ahead of where it had been

before the world war broke out. Aviation, both in its personnel and

its equipment, was included in that part of the Signal Corps known as

the Aviation Section, which had been established by Congress July 18,

1914. Its chief was Maj. Gen. George O. Squier, who after four years

as military attaché in London, had been put in charge of the Aviation

Section in May, 1916, and made Chief Signal Officer on February 14,

1917, continuing to have charge of aviation through nearly the whole of

the fiscal year. On April 6, 1917, the total assets on hand consisted

of 65 officers, 1,120 men, two small flying fields, less than 300 very

second-rate training planes, practically no manufacturing facilities,

and only the most meagre technical information as to Europe’s startling

developments.

The original American war program, based on an army of a million men,

made aviation but a relatively insignificant part of the general

military forces. This program, which represented the view of the

General Staff before the arrival of the foreign missions, was met by

two appropriations, $10,800,000 on May 12, 1917, and $43,450,000 on

June 15, many times larger than any appropriations ever before made.

The British and French missions, however, arriving the last part

of April, completely revolutionized this viewpoint. Supported by an

urgent cable of May 24 from the premier of France, calling for 2,000

planes a month and a total of 5,000 pilots and 50,000 mechanicians,

the $640,000,000 appropriation, the largest ever made by Congress

for one specific purpose, was drawn up, put through the House of

Representatives Military Affairs Committee in two meetings, the House

itself in one, the Senate Military Affairs Committee in 45 minutes,

and the Senate itself a week later, becoming law on July 24, 1917. On

this date the present large program was really launched, two months and

a half after the outbreak of war, and largely in response to allied

appeals.

The rest of the fiscal year was taken up in amplifying and executing

the lines of effort here laid down. Toward the end of the year,

however, it became obvious that the system of organization of an

Aviation Section as a subsidiary branch of the Signal Corps was not

functioning efficiently. The British and French, perceiving that we

were encountering the same kind of obstacles as theirs, strongly

recommended a separate, independent air service similar to the air

ministries they had been obliged to establish and which have worked

so successfully since. As a result, a first step was taken in a

rearrangement of duties designed to effect a greater independence

and a greater concentration of authority when, on April 24, the War

Department authorized the following statement:

“Mr. John D. Ryan has accepted the directorship of aircraft production

for the Army.

“A reorganization of the Aviation Section of the Signal Corps has been

also effected, of which the principal elements are as follows:

“Gen. Squier, as Chief Signal Officer, will devote his attention to

the administration of signals; a Division of Military Aeronautics

is created, under the direction of Brig. Gen. William L. Kenly. The

Aircraft Board, created by act of Congress, remains as an advisory

body, as it has been in the past, with Mr. Ryan as its chairman. This

arrangement is made with the entire concurrence of Mr. Howard Coffin,

who remains a member of the Advisory Commission of the Council of

National Defense and will render assistance and counsel to the Aircraft

Board and Mr. Ryan.

“The Division of Military Aeronautics will have control of the training

of aviators and military use of aircraft. The exact division of

functions in the matter of designing and engineering will be worked out

as experience determines between the Division of Military Aeronautics

and the Division of Production.

“This announcement involves no change of personnel in the present

Equipment Division of the Signal Corps, of which W. C. Potter is chief,

and which will continue under his direction.”

This reorganization, however, was admittedly but the first step. The

first action taken by the President under the broad powers of the

Overman Act was to effect a still further reorganization by taking

aviation entirely out of the jurisdiction of the Signal Corps, where

it has been from its inception on July 18, 1914, and to set up two

separate bureaus, one for securing and training the large flying

and ground forces, and the other for providing planes, engines, and

equipment.

The presidential order of May 21 covering this change follows:

“By virtue of the authority in me vested as Commander-in-Chief of the

Army and by virtue of further authority upon me specifically conferred

by ‘An act authorizing the President to coordinate or consolidate

executive bureaus, agencies, and offices, and for other purposes, in

the interest of economy and the more efficient concentration of the

Government,’ approved May 20, 1918, I do hereby make and publish the

following order:

“The powers heretofore conferred by law or by Executive order upon

and the duties and functions heretofore performed by the Chief Signal

Officer of the Army are hereby redistributed as follows:

I

“(1) The Chief Signal Officer of the Army shall have charge, under the

direction of the Secretary of War, of all military signal duties, and

of books, papers and devices connected therewith, including telegraph

and telephone apparatus and the necessary meteorological instruments

for use on target ranges, and other military uses; the construction,

repair, and operation of military telegraph lines, and the duty of

collecting and transmitting information for the Army by telegraph

or otherwise, and all other duties usually pertaining to military

signaling; and shall perform such other duties as now or are or shall

hereafter be devolved by law or by Executive order upon said Chief

Signal Officer which are not connected with the Aviation Section of

the Signal Corps or with the purchase, manufacture, maintenance, and

production of aircraft, and which are not hereinafter conferred, in

special or general terms, upon other officers or agencies.

“(2) A Director of Military Aeronautics, selected and designated by

the Commander in Chief of the Army, shall hereafter have charge,

under the direction of the Secretary of War, of the Aviation Section

of the Signal Corps of the Army, and as such shall be, and he hereby

is, charged with the duty of operating and maintaining or supervising

the operation and maintenance of all military aircraft, including

balloons and aeroplanes, all appliances pertaining to said aircraft

and signaling apparatus of any kind when installed on said aircraft,

and of training officers, enlisted men, and candidates for aviation

service in matters pertaining to military aviation, and shall hereafter

perform each and every function heretofore imposed upon and performed

by the Chief Signal Officer of the Army in, or in connection with,

the Aviation Section of the Signal Corps, except such as pertains to

the purchase, manufacture, and production of aircraft and aircraft

equipment and as is not hereinafter conferred, in special or general

terms, upon the Bureau of Aircraft Production; and all aeroplanes

now in use or completed and on hand and all material and parts, and

all machinery, tools, appliances, and equipment held for use for the

maintenance thereof; all lands, buildings, repair shops, warehouses,

and all other property, real, personal, or mixed, heretofore used

by the Signal Corps in, or in connection with, the operation and

maintenance of aircraft and the training of officers, enlisted men,

and candidates for aviation service, or procured and now held for such

use by or under the jurisdiction and control of the Signal Corps of

the Army; all books, records, files and office equipment heretofore

used by the Signal Corps, in, or in connection with, such operation,

maintenance, and training; and the entire personnel of the Signal Corps

as at present assigned to, or engaged upon work in, or in connection

with, such operation, maintenance, and training, is hereby transferred

from the jurisdiction of the Chief Signal Office and placed under

the jurisdiction of the Director of Military Aeronautics; it being

the intent hereof to transfer from the jurisdiction of the Chief

Signal Officer to the jurisdiction of the said Director of Military

Aeronautics every function, power, and duty conferred and imposed upon

said Director of Military Aeronautics by subparagraph (2) of paragraph

I hereof all property of every sort of nature used or procured for use

in, or in connection with, the functions of the Aviation Section of the

Signal Corps placed in charge of the Director of Military Aeronautics

by subparagraph (2) of paragraph I hereof, and the entire personnel of

the Signal Corps in charge of the Director of Military Aeronautics by

subparagraph (2) of paragraph I hereof.

“(3) An executive agency, known as the Bureau of Aircraft Production, is

hereby established, and said agency shall exercise full, complete, and

exclusive jurisdiction and control over the production of aeroplanes,

aeroplane engines, and aircraft equipment for the use of the Army,

and to that end shall forthwith assume control and jurisdiction over

all pending Government projects having to do or connected with the

production of aeroplanes, aeroplane engines, and aircraft equipment

for the Army and heretofore conducted by the Signal Corps of the Army,

under the jurisdiction of the Chief Signal Officer; and all material

on hand for such production, all unfinished aeroplanes and aeroplane

engines, and all unfinished, unattached, or unassembled aircraft

equipment; all lands, buildings, factories, warehouses, machinery,

tools, and appliances, and all other property, real, personal, or

mixed, heretofore used in or in connection with such production, or

procured and now held for such use, by or under the jurisdiction

and control of the Signal Corps of the Army; all books, records,

files, and office equipment used by the said Signal Corps in or in

connection with such production; all rights under contracts made by

the Signal Corps in or in connection with such production; and the

entire personnel of the Signal Corps as at present assigned to or

engaged upon work in or in connection with such production are hereby

transferred from the jurisdiction of the Signal Corps and placed under

the jurisdiction of the Bureau of Aircraft Production, it being the

intent thereof to transfer from the jurisdiction of the Signal Corps

to the jurisdiction of the said Bureau of Aircraft Production every

function, power, and duty connected with said production, all property

of every sort or nature used or procured for use in or in connection

with said production, and the entire personnel of the Signal Corps, as

at present assigned to or engaged upon work in or in connection with

such production.

“Such person as shall at the time be chairman of the Aircraft Board

created by the act of Congress approved October 1, 1917, shall also

be the executive officer of said Bureau of Aircraft Production, and

he shall be, and he hereby is, designated as Director of Aircraft

Production, and he shall, under the direction of the Secretary of

War, have charge of the activities, personnel, and properties of said

bureau.

II

“All unexpended funds of appropriations heretofore made for the

Signal Corps of the Army and already specifically allotted for use in

connection with the functions of the Signal Service as defined and

limited by subparagraph (1) of Paragraph I hereof shall be and remain

under the jurisdiction of the Chief Signal Officer; all such funds

already specifically allotted for use in connection with the functions

of the Aviation Section of the Signal Corps as defined and limited by

subparagraph (2) of Paragraph I hereof are hereby transferred to and

placed under the jurisdiction of the Director of Military Aeronautics

for the purpose of meeting the obligations and expenditures authorized

by said section; all such funds already specifically allotted for use

in connection with the functions hereby bestowed upon the Bureau of

Aircraft Production, as defined and limited by subparagraph (3) of

Paragraph I hereof, are hereby transferred to and placed under the

jurisdiction of said Director of Aircraft Production for the purpose

of meeting the obligations and expenditures authorized by said bureau

in carrying out the duties and functions hereby transferred to and

bestowed upon said bureau; and in so far as such funds have not been

already specifically allotted to the different fields of activity of

the Signal Corps as heretofore existing, they shall now be allotted

by the Secretary of War in such proportions as shall to him seem best

intended to meet the requirements of the respective fields of former

activity of the Signal Corps and the intention of Congress when making

said appropriations, and the funds so allotted by the Secretary of War

to meet expenditures in the field of activity of the Aviation Section

of the Signal Corps are hereby transferred to and placed under the

jurisdiction of the Director of Military Aeronautics for the purpose

of meeting the obligations and expenditures authorized by said

section; and the funds so allotted by the Secretary of War to meet

the expenditures in that part of the field of activity of the Signal

Corps, which includes the functions hereby transferred to the Bureau

of Aircraft Production, are hereby transferred to and placed under the

jurisdiction of the Director of Aircraft Production for the purpose of

meeting the obligations and expenditures authorized by said bureau.

III

“This order shall be and remain in full force and effect during the

continuance of the present war and for six months after the termination

thereof by the proclamation of the treaty of peace, or until

theretofore amended, modified, or rescinded.

“Under this order Mr. John D. Ryan continued as Director of Aircraft

Production and Maj. Gen. William L. Kenly became Director of Military

Aeronautics.”

This division of responsibilities and functions gave a clearer

conception of the unique duties of the Air Service in production of

planes and training of pilots, and is significant, too, of the many

tactical reasons which made it imperative for England and France to

establish separate and independent air services.

The end of the fiscal year found this problem of higher organization

one of the most important to be faced. An early defect discovered in

the reorganization developed when there appeared to be inadequate

liaison between the Bureau of Aircraft Production and the Division of

Military Aeronautics. One was responsible for the production of planes,

the other for their operation and military efficiency. The method of

selecting a type to put into production and the final decision whether

any plane produced was suitable for its military purposes or not,

was undetermined. The situation of two sets of officials with equal

authority in their respective fields of action, neither responsible

to the other, at once demonstrated that neither could be held for

the final production of an acceptable plane for the front. This was

partially obviated by an agreement between the Division of Military

Aeronautics and the Bureau of Aircraft Production that the types of

plane to be put into production must first be mutually agreed upon, and

that before a plane could be sent to the front it should be given a

military test and accepted by the Division of Military Aeronautics. But

considerable time was lost before this policy was definitely arranged,

a policy which might easily have at once been established by a unified

department.

The personnel side of the air service, including the selection,

training, organization, and operation of the flying forces, developed

within the fiscal year 1917-18 into an educational system on a scale

infinitely larger and more diverse than anyone had anticipated.

Teaching men to fly, to send messages by wireless, to operate

machine guns in the air, to know artillery fire by its bursts, and

to travel hundreds of miles by compass, teaching other men to read

the enemy’s strategy from aerial photographs, and still others to

repair instruments, ignition systems, propellers, aeroplane wings, and

motors, has required a network of flying fields and schools, a large

instructional force, and a maze of equipment and curricula.

None of this, practically speaking, was on hand at the outbreak of

the war, neither fields, instructors, curricula, nor, more serious

than all, experience to show what was to be needed. This country had

never trained an aviator sufficiently to meet the demands of overseas

aerial warfare and had not the slightest knowledge of the instruction

necessary for radio, photography, or enlisted personnel. Consequently,

the first men largely taught themselves before teaching others, and

experience led on from one course to the next.

First, in the point of need, was that of flying fields. Two were in

limited operation at the outbreak of war, San Diego and Mineola; three

more were selected, cleared, equipped, and made ready for flying in six

weeks’ time, and by the end of the year over a score were in operation

all over the country. All were protected by a three-year lease with

option to buy, if desired, at a fixed price. During the year also five

supply depots, three concentration depots, three balloon camps, two

repair depots, one experimental field, one radio laboratory, and one

quarantine camp were built.

The selection of men for training as flyers was a complicated task, as

the requirements were necessarily rigid. Volunteer examining boards

of the highest medical skill were organized all over the country, 36

urban and 30 divisional boards, and a total of 38,777 men were examined

to June 2, of whom nearly half, or 18,004, were disqualified. This

naturally led to a high grade of personnel, and made the later training

both more rapid and more efficient.

The first step in instruction was at one of the new “ground” schools

opened on May 21 at the Massachusetts Institute of Technology, Cornell

and Ohio State Universities and the Universities of Illinois, Texas,

and California, with Princeton and the Georgia School of Technology

added on July 5. Here, in eight weeks, under military discipline,

the cadets were grounded in all the elements of aviation at a cost

to the Government at first of $65 per pupil, and later $10 each for

the first four weeks, and $5 weekly thereafter. By June 30, 1918, a

total of 11,539 men were graduated to the flying fields and 3,129 were

discharged for failure in studies, etc.

Next came the actual flying instruction, divided into two phases,

primary and advanced. The former averaged about eight weeks, included

ability to execute the simpler evolutions and cross-country flights,

and led to an officer’s commission and the right to wear the Reserve

Military Aviator’s wings. To June 30, 1918, 4,980 men had been

graduated as Reserve Military Aviators for final training, and about

400 had been disqualified as incapable of becoming flyers.

The advanced training, however, presented infinitely more difficulties.

It was not nearly so simple to teach the more complex stunts, formation

flying, aerial machine gunnery, bombing, and night flying, while at

the same time the highly specialized equipment necessary required

considerable time for manufacture. Nevertheless, advanced schools of

the three types necessary were openeEarly western travels 1748-1846,

volume 7 of 10d toward the end of the year 1918, with what equipment

was available, and had graduated 110 bombers, 85 bombing pilots, 464

observers, 389 observer pilots, and 131 pursuit pilots by June 30, 1918.

The ideal arrangement in mind at the end of the year was to train each

pilot completely on this side of the ocean, where facilities are very

good, supplies in abundance, and information and experienced pilots

from the front available in ever-increasing numbers. The flyers can

then be organized into provisional squadrons and wings and given

training as large units with their own administrative officers and

enlisted personnel so that they will be able to go immediately to the

front, after a month or so of transformation work in France, learning

geography and familiarizing themselves with new types of planes. Plans

are under way looking to the establishment of such wings and brigades

in the United States with the end in view of furnishing complete and

fully trained units to the American Expeditionary Force.

The whole training program was considerably held up by lack of

equipment. Obviously it required far less time to select men for

training than to build the fields, planes, and accessories necessary

to train them. Primary training planes, the only type manufactured

here before the war, soon became available in increasing numbers, till

by the end of the year more were on hand than needed. The advanced

training planes, however, presented problems wholly new to this

country, so that primary planes had to be fitted with more powerful

engines and equipment and made to serve the purpose. The first 16

single-seater pursuit planes were not delivered till January, 1918, the

first bombers till March, and the first gunnery late in May.

During this fiscal year a grand total of 407,999 hours were flown by

Army aviators in the United States, as contrasted with 745.5 hours in

1914 and 1,269 in 1915. In the single week ending June 30, 1918, a

total of 19,560 hours were flown, or 15 times, for that single week,

the number of the whole year three years before. This, at 75 miles an

hour, is equivalent to over 30,000,000 miles, or 1,223 times around the

Equator.

During it there were 152 fatalities, or 2,684 flying hours and 201,000

miles flown to each death. Of these, 86 were caused by stalls, when

the plane, usually through some error by the pilot, lost its flying

speed and dropped into a straight nose dive or turned into a tail spin,

from which the pilot did not have the time or the skill to extricate

it. Collisions were responsible for 30 other accidents, often due to

failure to fly according to the rules. Side-slips, the only other large

cause of accidents, resulted in 10 deaths.

Regrettable as these accidents are, it is felt that, considering the

newness of the science, the early state of development of the planes,

the inexperience in instruction, and the necessity of teaching stunts

in themselves rather dangerous, this number is not large. As a matter

of actual statistics, fatalities in American training are less than

half as large as those of the other allied countries.

Besides flyers, however, engineer officers to direct the upkeep of the

equipment, supply officers to keep sufficient equipment on hand, and

adjutants to keep the records and do other military work had to be

especially trained. These men, absolutely essential to the maintenance

of the Air Service organization, could be secured only after a detailed

course of instruction. An engineers’ school, opened for a 12 weeks’

course at the Massachusetts Institute of Technology on January 12,

graduated 590 men and discharged 228 before June 30; a supply officers’

school, opened at the Georgia School of Technology, graduated 852 men

and discharged 111 from an eight weeks’ course before it was closed

on May 11; and an adjutants’ school, opened at Ohio State University

on January 12, graduated 789 and discharged 97 men in an eight weeks’

course before it was closed June 22.

A six weeks’ course for armament officers and men to care for machine

guns and bombs was opened at Fairfield, Ohio, on April 22, graduating

95 officers and 465 men by June 30, all of whom went forthwith

overseas. Just at the end of the year a series of special schools in

aerial gunnery were opened as the final step in the flyers’ training in

this country, graduating 102 pilots, 111 observers, and 101 fighting

observers by June 30. Also a special course for compass officers was

opened at Camp Dick, Texas, on April 10, with 53 graduates, and another

course at the same time for a score of navigation officers.

Radio also required very special instruction, with courses and

instructors for all flyers through the various stages of their

progress, for the receiving force on the ground, and for the men

responsible for the upkeep of the radio equipment. At the outset,

volunteer civilians, each with his own methods of instruction, stepped

into the breach, but by the end of the year two radio officers,

and four enlisted men’s schools were in operation with 49 and 329

graduates, respectively; radio officers and equipment had been sent

to every field and ground school; and the courses for flyers had been

standardized all the way through.

Aerial photography, which had developed during the war into an exact

science, required similar triple instruction—that for observers to

operate the cameras in the air, intelligence officers on the ground to

interpret them, and enlisted men to aid in the developing, printing,

and enlarging, and to keep the equipment in condition. Where the United

States had not even a single aerial camera at the outbreak of the war,

by the end of the year there had been opened on March 25 a large school

for developers and printers at Rochester, N. Y., with 680 graduates

by June 30, an officers’ school on January 6 at Cornell teaching map

compilation and interpretation, and photographic “huts” with complete

personnel and equipment for instruction at each of the flying fields.

One of the most serious problems, and one of late development, was

that of enlisted men, the ground force needed to keep the planes and

engines always in prime condition, repair minor breaks, tighten up

wires, strengthen struts, and make sure that no airman went up in a

faulty plane. This was work wholly new to American mechanics, and of

a delicacy and carefulness to which they were quite unaccustomed.

Moreover, mechanics of the skill required had largely been drained off

by the draft, by enlistment, or by other war industries.

Consequently, a whole series of schools was necessary. At first,

in the fall small detachments of mechanics were sent to various

factories—ignition, magneto, propeller, welding, instruments,

sail-making, cabinet work, copper work, machine guns, and motors to

secure as much experience as possible. While about 2,000 men were

being graduated from 17 courses at 34 different schools of this type,

more fully worked out courses were established at five northern flying

fields closed for flying during the winter. With 2,500 graduated here,

still more detailed courses were opened at four large mechanics’

schools, which added another 5,000 men. By the end of the year two

large and complete Government schools were in operation at Kelly Field,

Texas, and St. Paul, Minn., capable of graduating 5,000 men every three

months.

A noteworthy event of the year was the opening on May 15 of the first

regular aerial mail service in the United States between New York,

Philadelphia, and Washington. The Army furnished six planes and pilots,

shortly doubled, for a daily round trip, carrying about 350 pounds of

mail each way, and with a record of 50 minutes for the 90 miles between

Philadelphia and New York, and 1 hour and 50 minutes for the 135 miles

from Philadelphia to Washington. Ninety per cent of the trips were made

successfully.

Another vitally important phase of the Air Service is that of

ballooning, which during the war has been developing into a system

of ever-watchful sentries on guard all the way from the North Sea to

Switzerland. Less spectacular, perhaps, than the heavier-than-air

work, this branch of the service has a quite indispensable function.

The observer, swinging in a captive balloon at an altitude of a mile,

2 to 5 miles from the enemy’s lines, and with a range of vision of 8

miles in all directions, can make a far more detailed, minute-by-minute

analysis of the enemy’s movements than the wider visioned but

transitory aviator, and can maintain such a flow of minute information

to the staff below that no important movement can take place unobserved

within his view.

Here, also, at the outbreak of the war the United States was

practically without facilities. The only school was at Fort Omaha,

Nebr., recovered from complete abandonment the previous November, with

accommodations for 15 officers and 400 men, and equipment of balloon

shed, gas plant, two obsolete captive balloons, and some telephone

material. The original program of August 13 necessitated a very large

expansion, fully comparable to that in the heavier-than-air branch.

To meet the program the Fort Omaha school was enlarged in September to

accommodate 61 officers and 1,200 men; on December 28 Camp John Wise

was opened at San Antonio with a final capacity of 150 officers and

2,200 men, and special companies were sent to Fort Sill, Okla., for

cooperation with the Coast Artillery. By June 30, 440 balloon officers

had graduated, of whom 155 were fully qualified observers, and 73 had

been sent overseas. The enlisted strength stood at 9,621 with 1,382

abroad.

Thus, by the end of the fiscal year, the Air Service had in operation

an educational system complete in all the details necessary to man

this intricate service. Fields, curricula, instructors, and equipment

were on hand for the most diverse courses, and men were graduating in

hundreds trained to all the difficulties of operating aeroplanes and

translating their work into effective action. A total of 34,209 men had

been graduated from the various courses, with 20,976 men enrolled in 50

schools of 16 different types.

Many outside bodies were called upon to cooperate in this development.

Great Britain, France, and Italy all early established large aviation

missions in Washington which brought their three years of experience to

help solve problems confronted here for the first time. The National

Advisory Committee for Aeronautics, the Bureau of Standards, and

several joint Army and Navy Boards also added their information on the

subject.

Nevertheless the work was carried out under extreme difficulties.

Operation and production were not properly coordinated. Much time

was lost in having to obtain the necessary authority to build a new

field or secure increases in personnel, instead of being able to carry

out a main program with full independence and authority. Moreover,

experienced and trained personnel was lacking; work had to be done

while the actual organization to do it was being built up; much time

was lost in the expansion and moving about of offices in Washington,

some half a dozen times; while officers were constantly being shifted

between Washington, the fields, and overseas.

Meanwhile overseas, work of organization was similarly going on.

Hardly six weeks after the United States entered the war, namely, on

May 27, the first cadets sailed for France for training in the highly

developed French flying schools, till by the end of the year nearly

2,500 men were under instruction in France, England, Italy, and Canada.

The collapse of Russia, Italy’s serious defeat, and the weight thrown

on the allied services made it impossible, unfortunately, for the

Allies to meet the schedule of training planes necessary, so that

many of these cadets, the most promising of America’s material, were

in idleness for months. Nevertheless, what facilities were available

greatly advanced America’s aerial preparation and helped relieve the

shortage of equipment here. It was early in May, 1918, however, over a

year after America’s entry into the war, that the first German plane

fell victim to an aviator in the American service. About the same time

468 fully trained American aviators organized into 13 complete American

squadrons or brigades with British and French squadrons were actually

on the front, taking increasing toll of the enemy.

During the same time an enlisted force of 46,667 men had also been sent

overseas. The first to go were sent to France to lay the foundations

for the great organization soon to be built up, including training

fields, assembly depots for American-built planes, and aerodromes near

the front. Others were formed into service squadrons in England and

France to be ready as soon as American pilots were trained into their

own organizations. Still others went to relieve French skilled labor

of unskilled work so that they could go back into aeroplane factories,

while others went to England for the construction work necessary to

carry out the night bombing program.

Consequently, by June 30, 1918, two large training organizations

were in operation, the source of supply in this country training and

organizing thousands of pilots and men in all sorts of tasks and the

operation end overseas giving the final training in France, England,

and Italy the fast moving of fully trained squadrons to the front.

Where, at the outbreak of the war, there had been but 65 officers

in the Air Service, there were now 14,230; the enlisted strength,

similarly, had jumped from 1,120 to 124,767; the number of men in or

awaiting training for flyers from less than 100 to over 18,000. There

were 4,872 officers and 46,667 enlisted men overseas. Indeed, the Air

Service alone was by June 30, 1918, larger than the American Army at

the outbreak of the war. While its development had been infinitely

more complicated and much less rapid than expected, there is reason to

believe that it is essentially sound.

WILLIAM L. KENLY,

_Major-General, U. S. A._,

_Director of Military Aeronautics_.

The Secretary of War.

APPENDIX II

RECORDS OF ALLIED AND ENEMY ACES WITH NUMBER OF PLANES BROUGHT DOWN

K—Killed. D—Dead. C—Captured. W—Wounded.

BRITISH ACES

Major E. Mannock (k) 73

Colonel William A. Bishop 72

Major Raymond Collishaw 70

Captain James McCudden (k) 58

Captain Philip F. Fullard 48

Captain Donald E. McLaren (k) 48

Captain G. E. H. McElroy 46

Captain Albert Ball (k) 43

Captain J. I. T. Jones 40

Captain A. W. B. Proctor 39

Major Roderic S. Dallas 39

Captain W. G. Claxton (k) 37

Captain F. R. McCall 34

Captain Frank G. Quigley 34

Major Albert D. Carter 31

Captain Cedric E. Howell 30

Captain A. E. McKeever 30

Captain Henry W. Wollett 28

Captain Brunwin-Hales 27

Major William G. Barker 25

Captain W. L. Jordan 25

Captain John Andrews, (Lieutenant, 9) 24

Captain Francis McCubbin 23

Captain M. B. Frew, (Lieutenant, 8) 23

Captain John Gilmour 23

Captain E. Libby

Captain Robert A. Little 22

Captain A. H. Cobby 21

Captain G. E. Thomson (k) 21

Lieutenant John J. Malone 20

Lieutenant Allen Wilkenson 19

Captain E. G. McClaughey 19

Captain J. L. Trollope (c) 18

Captain Stanley Rosever (d) 18

Lieutenant Leonard M. Barlow 17

Captain Walter A. Tyrrell 15

Captain P. C. Carpenter 15

Lieutenant Clive Warman 15

Lieutenant Clive F. Collett (k) 15

Lieutenant Fred Libby 14

Lieutenant R. T. C. Hoidge 14

Captain H. G. Reeves (accident) 13

Captain Murray Galbraith 13

Lieutenant Joseph S. Fall 13

Captain Noel W. W. Webb (k) 12

Lieutenant A. J. Cowper 12

Lieutenant Alan Gerard 12

Captain Whitaker (in Italy) 12

Lieutenant M. D. G. Scott 11

Captain Robert Dodds 11

Captain Gilbert Ware Green 9

Lieutenant K. R. Park 9

Lieutenant Rhys-David 9

Lieutenant John H. T. Letts 8

Captain James A. Slater 8

Sergeant Dean K. Lamb 8

Lieutenant Boyd S. Breadner 8

Captain Wagour (in Italy) 7

Lieutenant Edward A. Clear 7

Captain Henry G. Luchford (k) 7

Captain C. A. Brewster-Joske 7

Lieutenant A. S. Sheppard 7

Lieutenant James Dennis Payne 7

Lieutenant Lionel B. Jones 7

Captain Lancelot L. Richardson 6

Lieutenant Cecil Roy Richards 6

Lieutenant Howard Saint 6

Lieutenant Fred John Gibbs 6

Lieutenant C. W. Cuddemore 6

Captain H. T. Mellings (w) 5

Commander R. F. Minifie (c) 5

Lieutenant Langley F. W. Smith 5

Lieutenant Ellis Vair Reed 5

Captain R. W. Chappell 5

Captain G. H. Boarman 5

Lieutenant F. T. S. Menedex 5

Captain Kennedy C. Patrick 5

Sergeant T. F. Stephenson 5

Lieutenant William Lewis Wells 5

Lieutenant E. D. Clarke 5

Captain Fred Hope Lawrence 5

Lieutenant Edward R. Grange 5

Lieutenant W. G. Miggett 5

Lieutenant Lawrence W. Allen 5

Lieutenant William D. Matheson 5

Lieutenant Stanley J. Coble 5

Captain S. T. Edwards 4

Captain A. R. Brown 4

Captain A. T. Whealy 4

Captain T. F. LeMesuries 4

Commander F. C. Armstrong 4

Commander E. L. N. Clarke 4

Commander R. B. Munday 4

Commander G. W. Price 4

Commander R. J. O. Compston 4

Lieutenant V. R. Stockes 4

Lieutenant W. C. Canbray 4

Lieutenant G. T. Beamish 3

Lieutenant E. T. Hayne 3

Lieutenant G. W. Hemming 3

Lieutenant J. E. L. Hunter 3

Lieutenant W. A. Curtiss 3

Lieutenant G. R. Crole 3

Lieutenant Robert N. Hall 3

Lieutenant David S. Hall 3

Lieutenant M. F. G. Day 3

Lieutenant E. G. Johnson 3

Lieutenant M. H. Findlay 3

Lieutenant C. B. Ridley 3

Lieutenant S. B. Horn 3

Lieutenant K. K. Muspratt 3

FRENCH ACES

Lieutenant Rene Fonck 75

Captain Georges Guynemer (k) 53

Lieutenant Charles Nungesser 43

Lieutenant Georges Madon 41

Lieutenant Maurice Boyau (k) 35

Lieutenant Coeffard (k) 34

Captain Pinsard 27

Lieutenant Rene Dorme (m) 23

Lieutenant Guerin (k) 23

Captain Heurteaux 21

Sergeant Marinovitch 21

Lieutenant Deullin 20

Adjutant Ehrlich 19

Lieutenant de Slade 19

Lieutenant Jean Chaput (k) 16

Lieutenant de Turrenne 15

Lieutenant de Meuldre (k) 13

Lieutenant Garaud 13

Lieutenant Nogues 13

Lieutenant Jailler 12

Lieutenant Marcel Hughes 12

Lieutenant Navarre (w) 12

Lieutenant Tarascon 12

Lieutenant de Sevin 12

Adjutant Casale 12

Lieutenant Leps 12

Lieutenant de La Tour (k) 11

Adjutant Maxime Lenoire (k) 11

Lieutenant Sardier 11

Lieutenant Ortoli 11

Sergeant Montrion (k) 11

Adjutant Herrison 11

Sergeant Bouyer 11

Lieutenant Bourgade 10

Adjutant Herbelin 10

Sergeant Quette (k) 10

Captain Georges Matton 9

Adjutant Chainat 9

Adjutant Dauchy 9

Lieutenant Viallet 9

Sergeant Sauvage (k) 8

Lieutenant de Rochefort (k) 7

Captain Rene Doumer (k) 7

Captain Alfred Auger (k) 7

Lieutenant Henri Languedoc (k) 7

Captain Derode 7

Lieutenant Lachmann 7

Lieutenant Flachaire 7

Adjutant Vitallis 7

Adjutant Sayaret 7

Lieutenant L’Hoste 7

Lieutenant Raymond 6

Sergeant du Bois d’Aische 6

Lieutenant Covin 6

Lieutenant Bonnefoy 6

Lieutenant Gond 6

Lieutenant Soulier 6

Sergeant Boyau 6

Adjutant Dhome 6

Adjutant Peronneau 6

Sergeant Rousseau 6

Private Louis Martin 6

Lieutenant de Mortemart (k) 6

Lieutenant Adolph Pegoud (k) 6

Sergeant Marcel Hauss (k) 5

Captain Lecour-Grandmaison (k) 5

Lieutenant Georges Baillot (k) 5

Adjutant Pierre Violet (k) 5

Lieutenant Andre Delorme (k) 5

Lieutenant Borzecky 5

Lieutenant Paul Gastin 5

Adjutant Bloch 5

Lieutenant Regnier 5

Commander Marancourt 5

Adjutant Blanc 5

Lieutenant Marty 5

Adjutant de Pralines 5

HUN ACES

Captain von Richthofen (k) 80

Lieutenant Udet 60

Lieutenant Werner Voss Crefeld (k) 49

Captain Boelke (k) 40

Lieutenant Gontermann (k) 39

Lieutenant Max Muller (k) 38

Lieutenant Bongartz 36

Captain Brunowsky (Austrian) 34

Lieutenant Max Buckler (k) 34

Lieutenant Menckhoff 34

Captain Berthold 33

Lieutenant Loerzer 33

Lieutenant Cort Wolff (k) 33

Lieutenant Koenneke 32

Lieutenant Balle 31

Lieutenant Schleich 30

Lieutenant Schaeffer (k) 30

Lieutenant Almenroder (k) 30

Lieutenant von Richthofen 29

Lieutenant Kroll 28

Lieutenant Prince von Bulow (k) 28

Lieutenant Wuesthoff (k) 28

Lieutenant Laumen 28

Lieutenant Boerr 28

Lieutenant Huey 28

Lieutenant Blume 28

Lieutenant Lowenhardt (k) 27

Captain von Tutscheck (k) 27

Lieutenant Barnett (k) 27

Lieutenant Dosler (k) 26

Lieutenant Arigi (Austrian) 26

Lieutenant Peutter (k) 25

Lieutenant Veltgens (k) 24

Lieutenant Erwin Boehm (k) 24

Corporal Rumey 23

Lieutenant Kirstein (k) 23

Lieutenant Link Crawford (k) 23

Lieutenant Fiala (Austrian) 23

Captain Baumer 23

Lieutenant Jakobs 22

Lieutenant Klein 22

Lieutenant Cluffort 22

Lieutenant Friedrichs (k) 21

Lieutenant Billik (k) 21

Lieutenant Wimdische (k) 21

Lieutenant Adam 21

Lieutenant Grein 20

Lieutenant Buechner 20

Lieutenant Thuy 20

Lieutenant von Tschwibon 20

Captain Reinhardt 20

Lieutenant von Eschwege (k) 20

Lieutenant Bethge (k) 20

Captain Behr 19

Lieutenant Thulzer 19

Lieutenant Baldamus 18

Lieutenant Wintgens (k) 18

Lieutenant Frankel (k) 17

Lieutenant Kissenberth 17

Lieutenant Schmidt 15

Lieutenant Geigle (k) 15

Lieutenant Schneider 15

Lieutenant Immelmann 15

Lieutenant Nathanall 14

Lieutenant Dassenbach 14

Lieutenant Festner 13

Lieutenant Hess 13

Lieutenant Muller 13

Lieutenant Goettsch 13

Lieutenant Pfeiffer 12

Lieutenant Manschatt (k) 12

Lieutenant Hohnforf (k) 12

Lieutenant Muttschaat 12

Lieutenant Buddecke (k) 12

Lieutenant von Kendall (k) 11

Lieutenant Kirmaier 11

Lieutenant Theiller 11

Lieutenant Serfert 11

Lieutenant Goering 10

Lieutenant Mulzer 10

Lieutenant Frickart 9

Lieutenant Banfield 9

Lieutenant Leffers (k) 9

Lieutenant Schulte 9

Lieutenant Parschau (k) 8

Lieutenant Schilling 8

Lieutenant von Althaus 8

Lieutenant Esswein 6

Lieutenant Walz 6

Lieutenant Hehn 6

Lieutenant Koenig 6

Lieutenant Fahlbusch 5

Lieutenant von Siedlitz 5

Lieutenant Rosenkranz 5

Lieutenant Habor 5

Lieutenant Reimann 5

Captain Zauder 5

Lieutenant Brauneck 5

Lieutenant Ullmer 5

Lieutenant Roth 5

ITALIAN ACES

Major Baracca (k) 36

Lieutenant Flavio Barachini 31

Lieutenant Olivari (k) 21

Lieutenant Anchilotti 19

Colonel Piccio 17

Captain, Duke Calabria 16

Lieutenant Scaroni 13

Lieutenant Hanza 11

Sergeant Maisero 8

Lieutenant Parnis 7

Sergeant Poli 6

Lieutenant Luigi Olivi 6

Lieutenant Stophanni 6

Lieutenant Arrigoni 5

BELGIAN ACES

Lieutenant Coppens 30

Lieutenant de Meulemesster 10

Lieutenant Thieffry (k) 10

Lieutenant Jan Olieslagers 6

Adjutant Beulemest 6

Captain Jaquette 5

Lieutenant Robin 5

Lieutenant Medaets 5

RUSSIAN ACES

Captain Kosakoff 17

Captain Kroutenn (k) 6

Lieutenant Pachtchenko 5

TURKISH ACE

Captain Schetz 8

APPENDIX III

NOMENCLATURE FOR AERONAUTICS

BY THE NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

INTRODUCTION

The following nomenclature was adopted by the National Advisory

Committee for Aeronautics at its annual meeting October 10, 1918.

The purpose of its adoption and publication is to help secure

uniformity in the official documents of the government as well as in

the technical journals.

AERONAUTICAL NOMENCLATURE

AEROFOIL: A winglike structure, flat or curved, designed to obtain

reaction upon its surfaces from the air through which it moves.

AEROFOIL SECTION: A section of an aerofoil made by a plane parallel to

the plane of symmetry of the aerofoil.

AEROPLANE: See Airplane.

AILERON: A movable auxiliary surface, usually part of the trailing

edge of a wing, the function of which is to control the lateral

attitude of an airplane by rotating it about its longitudinal axis.

AIRCRAFT: Any form of craft designed for the navigation of the

air—airplanes, airships, balloons, helicopters, kites, kite balloons,

ornithopters, gliders, etc.

AIRPLANE: A form of aircraft heavier than air which has wing surfaces

for support in the air, with stabilizing surfaces, rudders for

steering, and power plant for propulsion through the air. This term

is commonly used in a more restricted sense to refer to airplanes

fitted with landing gear suited to operation from the land. If

the landing gear is suited to operation from the water, the term

“seaplane” is used. (See definition.)

_Pusher._—A type of airplane with the propeller in the rear of the

engine.

_Tractor._—A type of airplane with the propeller in front of the

engine.

AIRSHIP: A form of balloon, the outer envelope of which is of elongated

form, provided with a propelling system, car, rudders, and stabilizing

surfaces.

_Nonrigid._—An airship whose form is maintained by the pressure of

the contained gas assisted by the car-suspension system.

_Rigid._—An airship whose form is maintained by a rigid structure

contained within the envelope.

_Semirigid._—An airship whose form is maintained by means of a rigid

keel and by gas pressure.

AIR-SPEED METER: An instrument designed to measure the speed of an

aircraft with reference to the air.

ALTIMETER: An aneroid mounted on an aircraft to indicate continuously

its height above the surface of the earth. Its dial is marked in feet,

yards, or meters.

ANEMOMETER: Any instrument for measuring the velocity of the wind.

ANGLE:

_Of attack_ (or _of incidence_) _of an aerofoil_.—The acute angle

between the direction of the relative wind and the chord of an

aerofoil; i. e., the angle between the chord of an aerofoil and its

motion relative to the air. (This definition may be extended to any

body having an axis.)

_Critical._—The angle of attack at which the lift-curve has its first

maximum; sometimes referred to as the “burble point.”

_Gliding._—The angle the flight path makes with the horizontal when

descending in still air under the influence of gravity alone; i. e.,

without power from the engine.

ANGLE OF INCIDENCE (_in directions for rigging_): In the process of

rigging an airplane some arbitrary definite line in the airplane is

kept horizontal; the angle of incidence of a wing, or of any aerofoil,

is the angle between its chord and this horizontal line, which usually

is the line of the upper longitudinals of the fuselage or nacelle.

APPENDIX: The hose at the bottom of a balloon used for inflation. In

the case of a spherical balloon it also serves for equalization of

pressure.

ASPECT RATIO: The ratio of span to chord of an aerofoil.

ATTITUDE: The attitude of an aircraft is determined by the inclination

of its axes to the “frame of reference”; e. g., the earth, or the

relative wind.

AVIATOR: The operator or pilot of heavier-than-air craft. This term is

applied regardless of the sex of the operator.

AXES OF AN AIRCRAFT: Three fixed lines of reference; usually centroidal

and mutually rectangular.

The principal longitudinal axis in the plane of symmetry, usually

parallel to the axis of the propeller, is called the _longitudinal_

axis; the axis perpendicular to this in the plane of symmetry is

called the _normal_ axis; and the third axis, perpendicular to the

other two, is called the _lateral_ axis. In mathematical discussions

the first of these axes, drawn from front to rear, is called the X

axis; the second, drawn upward, the Z axis; and the third, running

from right to left, the Y axis.

BALANCING FLAPS: See Aileron.

BALLONET: A small balloon within the interior of a balloon or

airship for the purpose of controlling the ascent or descent and

for maintaining pressure on the outer envelope so as to prevent

deformation. The ballonet is kept inflated with air at the required

pressure, under the control of valves by a blower or by the action of

the wind caught in an air-scoop.

BALLOON: A form of aircraft comprising a gas bag, rigging and a basket.

The support in the air results from the buoyancy of the air displaced

by the gas bag, the form of which is maintained by the pressure of a

contained gas lighter than air.

_Barrage._—A small spherical captive balloon, raised as a protection

against attacks by airplanes.

_Captive._—A balloon restrained from free flight by means of a cable

attaching it to the earth.

_Kite._—An elongated form of captive balloon, fitted with tail

appendages to keep it headed into the wind, and deriving increased

lift due to its axis being inclined to the wind.

_Pilot._—A small spherical balloon sent up to show the direction of

the wind.

_Sounding._—A small spherical balloon sent aloft without passengers

but with registering meteorological instruments.

BALLOON BED: A mooring place on the ground for a captive balloon.

BALLOON CLOTH: The cloth, usually cotton, of which balloon fabrics are

made.

BALLOON FABRIC: The finished material, usually rubberized, of which

balloon envelopes are made.

BANK: To incline an airplane laterally—i.e., to roll it about the

longitudinal axis. Right bank is to incline the airplane with the right

wing down. Also used as a noun to describe the position of an airplane

when its lateral axis is inclined to the horizontal.

BANK, ANGLE OF: The angle through which an aircraft must be rotated

about its longitudinal axis in order to bring its lateral axis into the

horizontal plane.

BAROGRAPH: An instrument used to record variations in barometric

pressure. In aeronautics the charts on which the records are made

indicate altitudes directly instead of barometric pressures.

BASKET: The car suspended beneath a balloon, for passengers, ballast,

etc.

BIPLANE: A form of airplane in which the main supporting surface is

divided into two parts, one above the other.

BODY OF AN AIRPLANE: See Fuselage and Nacelle.

BONNET: The appliance, having the form of a parasol, which protects the

valve of a spherical balloon against rain.

BRIDLE: The system of attachment of cable to a balloon, including lines

to the suspension band.

BULL’S-EYES: Small rings of wood, metal, etc., forming part of balloon

rigging, used for connection or adjustment of ropes.

BURBLE POINT: See Angle, critical.

CABANE: A pyramidal framework upon the wing of an airplane, to which

stays, etc., are secured.

CAMBER: The convexity or rise of the curve of an aerofoil from its

chord, usually expressed as the ratio of the maximum departure of the

curve from the chord to the length of the chord. “Top camber” refers

to the top surface of an aerofoil, and “bottom camber” to the bottom

surface; “mean camber” is the mean of these two.

CAPACITY: See Load. The cubic contents of a balloon.

CEILING: _Service._—The height above sea level at which a given

aircraft ceases to rise at a rate higher than a small specified one,

say 100 feet per minute. This specified rate may be different in the

services of different countries.

_Absolute._—The maximum height above sea level to which a given

aircraft can rise.

_Theoretical._—The limiting height to which a given aircraft can rise

determined by computations of performance, based upon the drawings and

wind tunnel data.

CENTER OF PRESSURE OF AN AEROFOIL: The point in the plane of the chords

of an aerofoil, prolonged if necessary, through which at any given

attitude the line of action of the resultant air force passes. (This

definition may be extended to any body.)

CHORD OF AN AEROFOIL SECTION:

_For theoretical purposes._—The zero lift line, i. e., the limiting

position, in the section, of the line of action of the resultant air

force when the position of the section is such that the lift is zero.

_Practical._—The line of a straightedge brought into contact with the

lower surface of the section at points near its edges. In the case of

an aerofoil having double convex camber, the straight line joining the

entering and trailing edges.

_Length._—The length of the chord is the length of the projection of

the aerofoil section on its chord.

CLINOMETER: See Inclinometer.

CONCENTRATION RING: A hoop to which are attached the ropes suspending

the basket of a spherical balloon.

CONTROLS: A general term applying to the means provided for operating

the devices used to control speed, direction of flight, and attitude of

an aircraft.

CONTROL COLUMN: The vertical lever by means of which certain of the

principal controls are operated, usually those for pitching and rolling.

CROSS-WIND FORCE: The component perpendicular to the lift and to the

drag of the total force on an aircraft due to the air through which it

moves.

CROW’S-FOOT: A system of diverging short ropes for distributing the

pull of a single rope.

DECALAGE: The angle between the chords of the principal and the

tail planes of a monoplane. The same term may be applied to the

corresponding angle between the direction of the chord or chords of

a biplane and the direction of a tail plane. (This angle is also

sometimes known as the longitudinal V of the two planes.)

DIHEDRAL IN AN AIRPLANE: The angle included at the intersection of

the imaginary surfaces containing the chords of the right and left

planes (continued to the plane of symmetry if necessary). This angle is

measured in a plane perpendicular to that intersection. The measure of

the dihedral is taken as 90° minus one-half of this angle as defined.

The dihedral of the upper planes may and frequently does differ from

that of the lower planes in a biplane.

DIRIGIBLE: See Airship.

DIVING RUDDER: See Elevator.

DOPE: A general term applied to the material used in treating the cloth

surface of airplane members and balloons to increase strength, produce

tautness, and act as a filler to maintain air-tightness; it usually has

a cellulose base.

DRAG: The component parallel to the relative wind of the total force on

an aerofoil or aircraft due to the air through which it moves.

In the case of an airplane, that part of the drag due to the wings

is called “wing resistance”; that due to the rest of the airplane is

called “parasite resistance.”

DRIFT: See Drag. Also used as synonymous with “leeway,” q. v.

DRIFT METER: An instrument for the measurement of the angular deviation

of an aircraft from a set course, due to cross winds.

DRIP CLOTH: A curtain around the equator of a balloon, which prevents

rain from dripping into the basket.

DROOP: A permanent warp of an aerofoil such that the angle of attack

increases toward the wing tips. (The opposite of “wash out.”)

ELEVATOR: A movable auxiliary surface, usually attached to the tail,

the function of which is to control the longitudinal attitude of an

aircraft by rotating it about its lateral axis.

EMPENNAGE: The tail surfaces of an aircraft. Sometimes the word

is limited to the fixed stabilizing portion of the tail—usually

comprising the tail plane and vertical fin, to which are attached the

elevator and rudders.

ENTERING EDGE: The foremost edge of an aerofoil or propeller blade.

ENVELOPE: The outer covering of a rigid airship; or, in the case of a

balloon or a nonrigid airship, the gas bag which contains the gas.

EQUATOR: The largest horizontal circle of a spherical balloon.

FINS: Small fixed aerofoils attached to different parts of aircraft,

in order to promote stability; for example, tail fins, skid fins, etc.

Fins are often adjustable. They may be either horizontal or vertical.

FLIGHT PATH: The path of the center of gravity of an aircraft with

reference to the earth.

FLOAT: That portion of the landing gear of an aircraft which provides

buoyancy when it is resting on the surface of the water.

FUSELAGE: The elongated structure to which are attached the landing

gear, wings and tail. A fuselage is rarely used with pushers; and in

general it is designed to hold the passengers.

GAP: The shortest distance between the planes of the chords of

the upper and lower planes of a biplane, measured along a line

perpendicular to the chord of the lower plane at its entering edge.

GAS BAG: See Envelope.

GLIDE: To fly without engine power.

GLIDER: A form of aircraft similar to an airplane, but without any

power plant.

When utilized in variable winds it makes use of the soaring principles

of flight and is sometimes called a soaring machine.

GLIDING ANGLE: See Angle, gliding.

GORE: One of the segments of fabric composing the envelope.

GROUND CLOTH: Canvas placed on the ground to protect a balloon.

GUIDE ROPE: The long trailing rope attached to a spherical balloon or

airship, to serve as a brake and as a variable ballast.

GUY: A rope, chain, wire or rod attached to an object to guide or

steady it, such as guys to wing, tail, or landing gear.

HANGAR: A shed for housing airships or airplanes.

HELICOPTER: A form of aircraft whose support in the air is derived from

the vertical thrust of propellers.

HORN: A short arm fastened to a movable part of an airplane, serving as

a lever arm, e. g., aileron horn, rudder horn, elevator horn.

HULL OF AN AIRSHIP: The main structure of a rigid airship, consisting

of a covered elongated framework which incloses the gas bags and which

supports the nacelles and equipment.

INCLINOMETER: An instrument for measuring the angle made by any axis of

an aircraft with the horizontal, often called a clinometer.

INSPECTION WINDOW: A small transparent window in the envelope of a

balloon or in the wing of an airplane to allow inspection of the

interior.

KITE: A form of aircraft without other propelling means than the

towline pull, whose support is derived from the force of the wind

moving past its surface.

LANDING GEAR: The understructure of an aircraft designed to carry the

load when resting on or running on the surface of the land or water.

LEADING EDGE: See Entering edge.

LEEWAY: The angular deviation from a set course over the earth, due to

cross currents of wind, also called drift; hence, “drift meter.”

LIFT: The component of the total force due to the air resolved

perpendicular to the relative wind and in the plane of symmetry.

LIFT OF AN AIRSHIP:

_Dynamic._—The component of the total force on an airship due to the

air through which it moves, resolved perpendicular to the relative

wind and in the plane including the direction of the relative wind and

the longitudinal axis.

_Static._—The vertical upward force on an airship when at rest in the

air, due to buoyancy.

LIFT BRACING: See Stay.

LOAD:

_Dead._—The structure, power plant, and essential accessories of an

aircraft. Included in this are the water in the radiator, tachometer,

thermometer, gauges, airspeed indicator, levels, altimeter, compass,

watch, and hand starter.

_Full._—The total weight of an aircraft when loaded to the maximum

authorized loading of that particular type.

_Useful._—The excess of the full load over the dead-weight of

the aircraft itself. Therefore useful load includes the crew and

passengers, oil and fuel, electric-light installation, chart board,

gun mounts, bomb storage and releasing gear, wireless apparatus, etc.

LOADING: See Wing loading.

LOBES: Bags at the stern of an elongated balloon designed to give it

directional stability.

LONGERON: See Longitudinal.

LONGITUDINAL: A fore-and-aft member of the framing of an airplane body

or of the floats, usually continuous across a number of points of

support.

LOOP, A: An aerial maneuver in which the airplane describes an

approximately circular path in the plane of the longitudinal and normal

axes, the lateral axis remaining horizontal, and the upper side of the

airplane remaining on the inside of the circle.

MAROUFLAGE: The process of wrapping and winding wooden parts in cloth.

MONOPLANE: A form of airplane which has but one main supporting

surface extending equally on each side of the body.

MOORING BAND: The band of tape over the top of a balloon to which are

attached the mooring ropes.

NACELLE: The inclosed shelter for passengers or for an engine. Usually

in the case of a single-engine pusher it is the central structure to

which the wings and landing gear are attached.

NET: A rigging made of ropes and twine on spherical balloons which

supports the entire load carried.

ORNITHOPTER: A form of aircraft deriving its support and propelling

force from flapping wings.

OVERHANG: One-half the difference in the span of the upper and lower

planes of a biplane.

PANCAKE: To “level off” an airplane, just before landing, at too great

an altitude, thus stalling it and causing it to descend with the wings

at a very large angle of incidence.

PANEL: The unit piece of fabric of which the envelope is made.

PARACHUTE: An apparatus, made like an umbrella, used to retard the

descent of a falling body.

PATCH SYSTEM: A system of construction in which patches (or adhesive

flaps) are used in place of the suspension band.

PERMEABILITY: The measure of the loss of gas by diffusion, through the

intact balloon fabric.

PITCH OF A PROPELLER:

(_a_) _Pitch, effective._—The distance an aircraft advances along its

flight path for one revolution of the propeller.

(_b_) _Pitch, geometrical._—The distance an element of a propeller

would advance in one revolution if it were turning in a solid nut—i.

e., if it were moving along a helix of slope equal to the angle

between the chord of the element and a plane perpendicular to the

propeller axis. The mean geometrical pitch of a propeller, which

is a quantity commonly used in specifications, is the mean of the

geometrical pitches of the several elements.

(_c_) _Pitch, virtual._—The distance a propeller would have to

advance in one revolution in order that there might be no thrust.

(_d_) _Pitch speed._—The product of the mean geometrical pitch by the

number of revolutions of the propeller in unit time—i. e., the speed

the aircraft would make if there were no slip.

(_e_) _Slip._—The difference between the effective pitch and the mean

geometrical pitch. Slip is usually expressed as a percentage of the

mean geometrical pitch.

PITCH, ANGLE OF: The angle between two planes, defined as follows: One

plane includes the lateral axis of the aircraft and the direction of

the relative wind; the other plane includes the lateral axis and the

longitudinal axis. (In horizontal normal flight this angle of pitch is,

then, the angle between the longitudinal axis and the direction of the

relative wind.)

PITOT TUBE: A tube with an end open square to the fluid stream, used

as a detector of an impact pressure. It is usually associated with a

coaxial tube surrounding it, having perforations normal to the axis

for indicating static pressure; or there is such a tube placed near it

and parallel to it, with a closed conical end and having perforations

in its side. The velocity of the fluid can be determined from the

difference between the impact pressure and the static pressure, as read

by a suitable gauge. This instrument is often used to determine the

velocity of an aircraft through the air.

PLANE: One of the main supporting surfaces of an airplane or of a wing.

(Thus the upper or lower plane of an airplane or the upper right plane

or lower right plane of the right wing.)

PONTOONS: See Float.

PRESSURE NOZZLE: The apparatus which, in combination with a gauge, is

used to measure speed through the air.

PUSHER: See Airplane.

PYLON: A mast or pillar serving as a marker of a course.

RACE OF A PROPELLER: See Slip stream.

RATE OF CLIMB: The vertical component of the flight speed of an

aircraft—i. e., its vertical velocity with reference to the air.

RELATIVE WIND: The motion of the air with reference to a moving

body. Its direction and velocity, therefore, are found by adding two

vectors, one being the velocity of the air with reference to the earth,

the other being equal and opposite to the velocity of the body with

reference to the earth.

RIGHT-HAND ENGINE: An engine designed to drive a right-hand tractor

screw.

RIGHTING MOMENT: A moment which tends to restore an aircraft to its

previous attitude after any rotational disturbance.

RIP CORD: The rope running from the rip panel of a balloon to the

basket, the pulling of which causes immediate deflation.

RIP PANEL: A strip in the upper part of a balloon which is torn off

when immediate deflation is desired.

ROLL, A: An aerial maneuver in which a complete revolution about the

longitudinal axis is made, the direction of flight being maintained.

RUDDER: A hinged or pivoted surface, usually more or less flat or

stream lined, used for the purpose of controlling the attitude of an

aircraft about its normal axis—i. e., for controlling its lateral

movement.

_Balanced._—A rudder having part of its surface in front of its pivot.

RUDDER BAR: The foot bar by means of which the rudder is operated.

SEAPLANE: A particular form of airplane in which the landing gear is

suited to operation from the water.

(_a_) _Boat seaplane_ (or _flying boat_).—A form of seaplane having

for its central portion a boat which provides flotation. It is often

provided with auxiliary floats or pontoons.

(_b_) _Float seaplane._—A form of seaplane in which the landing gear

consists of one or more floats or pontoons.

SERPENT: A short, heavy guide rope.

SIDE SLIPPING: Sliding downward and inward when making a turn; due to

excessive banking. It is the opposite of skidding.

SKIDDING: Sliding sidewise away from the center of the turn in flight.

It is usually caused by insufficient banking in a turn and is the

opposite of side slipping.

SKIDS: Long wooden or metal runners designed to prevent nosing of a

land machine when landing or to prevent dropping into holes or ditches

in rough ground. Generally designed to function should the landing gear

collapse or fail to act.

SLIP STREAM (or _propeller race_): The stream of air driven aft by the

propeller and with a velocity relative to the airplane greater than

that of the surrounding body of still air.

SOARING MACHINE: See Glider.

SPAN (or _spread_): The maximum distance laterally from tip to tip of

an airplane or the lateral dimension of an aerofoil.

SPEED: _Air._—The speed of an aircraft relative to the air.

_Ground._—The horizontal component of the velocity of an aircraft

relative to the earth.

SPIN: An aerial maneuver consisting of a combination of roll and yaw,

with the longitudinal axis of the airplane inclined steeply downward.

The machine descends in a helix of large pitch and very small radius,

the upper side of the machine being on the inside of the helix, and the

angle of attack being maintained at a large value.

STABILITY: A body in any attitude has stability about an axis if, after

a slight displacement about that axis, it tends to regain its initial

attitude.

_Directional._—Stability with reference to the normal axis.

_Dynamical._—The quality of an aircraft in flight which causes it

to return to a condition of equilibrium after its attitude has been

changed by meeting some disturbance—e. g., a gust. This return to

equilibrium is due to two factors: First, the inherent righting

moments of the structure; second, the damping of the oscillations by

the tail, etc.

_Inherent._—Stability of an aircraft due to the disposition and

arrangement of its fixed parts, i. e., that property which causes it

to return to its normal attitude of flight without the use of the

controls.

_Lateral._—Stability with reference to displacements involving

rolling or yawing, i. e., displacements in which the plane of symmetry

of the airplane is rotated.

_Longitudinal._—Stability with reference to displacements involving

pitching, i. e., displacements in which the plane of symmetry of the

airplane is not rotated.

_Statical._—In wind-tunnel experiments it is found that there is a

definite angle of attack, such that, for a greater angle or a less

one, the righting moments are in such a sense as to tend to make the

attitude return to this angle. This holds true for a certain range of

angles on each side of this definite angle; and the machine is said to

possess “statical stability” through this range.

A machine possesses statical stability if, when its attitude is

disturbed, moments tending to restore it to this attitude are set

up by the action of the air on the machine; e. g., if an aircraft,

after an initial disturbance, oscillates with swings of constantly

increasing amplitude, it is statically stable but not dynamically

stable.

STABILIZER: A fixed horizontal, or nearly horizontal, tail surface,

used to steady the longitudinal motion and to damp oscillations in

pitch.

_Mechanical._—A mechanical device to steady the motion of an aircraft.

STAGGER: The amount of advance of the entering edge of the upper plane

of a biplane over that of the lower, expressed as percentage of gap;

it is considered positive when the upper surface is forward and is

measured from the entering edge of the upper plane along its chord to

the point of intersection of this chord with a line drawn perpendicular

to the chord of the lower plane at its entering edge, all lines being

drawn in a plane parallel to the plane of symmetry.

(_In directions for rigging_).—The horizontal distance between the

entering edge of the upper plane and that of the lower when the

airplane is in the standard position; i. e., when the arbitrary line

of reference in the airplane is horizontal. (This line is usually the

axis of the propeller shaft.)

STALLING: A term describing the condition of an airplane which from any

cause has lost the relative speed necessary for control.

STATOSCOPE: An instrument to detect the existence of a small rate of

ascent or descent, principally used in ballooning.

STAY: A wire, rope, or the like, used as a tie piece to hold parts

together, or to contribute stiffness. For example, the stays of the

wing and body trussing.

STEP: A break in the form of the bottom of a float.

STREAM-LINE FLOW: The condition of continuous flow of a fluid, as

distinguished from eddying flow.

STREAM-LINE SHAPE: A shape intended to avoid eddying and to preserve

stream-line flow.

STRUT: A compression member of a truss frame. For instance, the

vertical members of the wing truss of a biplane.

SUSPENSION BAND: The band around a balloon to which are attached the

basket and the main bridle suspensions.

SUSPENSION BAR: The bar used for the concentration of basket suspension

ropes in captive balloons.

SWEEP BACK: The horizontal angle between the lateral axis of an

airplane and the entering edge of the main planes.

TAIL: The rear portion of an aircraft, to which are usually attached

rudders, elevators, stabilizers, and fins.

TAIL CUPS: The steadying device attached at the rear of certain types

of elongated captive balloons.

TANDEM: An airplane whose sets of planes are placed one in front of the

other.

TRACTOR: See Airplane.

TRAILING EDGE: The rearmost edge of an aerofoil or propeller blade.

TRIPLANE: A form of airplane whose main supporting surface is divided

into three parts, superimposed.

TRUSS: The framing by which the wing loads are transmitted to the body;

comprises struts, stays, and spars.

UNDERCARRIAGE: See Landing gear.

VENTURI TUBE: A short tube, flaring at the front end, and constricted

approximately midway of its length, so that, when fluid flows through

it, there will be a suction produced in a side-tube opening into the

constricted throat. This tube, when combined with a Pitot tube or with

one giving static pressure, forms a pressure nozzle, which may be used

as an instrument to determine the speed of an aircraft through the air.

WARP: To change the form of the wing by twisting it.

WASH IN: See Droop.

WASHOUT: A permanent warp of an aerofoil such that the angle of attack

decreases toward the wing tips.

WEIGHT, GROSS: See Load, full.

WING: The aggregate sustaining structure on the right or left side of

an airplane, comprising both planes and trussing. (Thus, “detachable

wings” and “folding wings.”)

WING FLAP: See Aileron.

WING LOADING: The weight carried per unit area of supporting surface.

WING MAST: The mast structure projecting above the wing, to which the

top load wires are attached.

WING RIB: A fore-and-aft member of the wing structure used to support

the covering and to give the wing section its form.

WING SPAR OR WING BEAM: A transverse member of the wing structure.

YAW: _Yawing_.—Angular motion about the normal axis.

_Angle of_.—The angle between the direction of the relative wind and

the plane of symmetry of an aircraft.

ZERO LIFT LINE: The limiting position in an aerofoil section of the

line of action of the resultant air force when the position of the

section is such that the lift is zero.

Transcriber’s Notes

Page 59—Changed Farmborough to Farnborough

Page 148—changed Chatterick to Catterick

Page 165—changed condension to condensation

Page 248—Space left for unknown word [not below the rank of ]

Page 251—changed Clefden to Clifden

Page 298—changed Porta Delgada to Ponta Delgada

Page 298—changed reconnoissance to reconnaissance

Page 354—Captain E. Libby no number of planes brought down recorded

Page 365—changed axes to axis