had developed some good engines, they never succeeded in securing an engine of this type for large production (560).

America took up the solution of this problem for herself and the Allies. On the 29th day of May, 1917, an initial attempt at designing a motor of this character was begun and finally resulted in the Liberty motor. An eight-cylinder Liberty was tested on the 4th day of July, 1917, and on the 25th of August, 1917, a 12-cylinder Liberty motor successfully passed the 50-hour test (3294, 3295).

On the 4th of September, 1917, the first contract for Liberty engines was let (3556).

The first Liberty engine completed was delivered to the Navy at Buffalo and tried on a flying boat in October 1917. The operating section of the Navy examined it and declared it satisfactory, with the addition of some slight improvements. The Navy then arranged to secure a large quantity of Libertys. Minor difficulties developed in the Liberty engine, such as accompany every effort to develop a new mechanism, but fundamentally it was a successful engine from its August trial. The military authorities of the World War finally concluded that six months' service was necessary to demonstrate the complete success of any engine (561).

The program of production of Liberty engines was as follows:

The total production to the date of the armistice was 13,574 and to the 31st of December, 17,935 (504). It will thus be seen that in the month of October 1918 the Liberty engine was being produced at the rate of over 46,000 per year. The engine production of the United States during the last 9 months of the war practically equaled the English production for the same period, notwithstanding the United States was in the war 19 months while England was in 51 months (561-a-b).

Up to the time of the armistice we had delivered to France 405 Liberty engines and to England 980 (555-a). Shortly after that the total reached 2,252 to the British and 3,575 to the French. At the time of the armistice the Allies were planning to put the Liberty engine into every class of service plane above the size of a pursuit plane (3084). The United States then had orders from the Allies for the delivery of 16,741 Liberty motors.

During the war the United States built 7,800,000 horsepower in aeronautical engines-a power equivalent to 8,000 average locomotives. The total represents approximately one-eighth of the total locomotive power of the United States-a power sufficient to haul 5,000 miles of freight cars (3134).

Quantity production of Liberty engines was developed with splendid speed when compared with other airplane engine developments. Mr. Keys, of the Curtiss Co., though not a manufacturer of the

Liberty, declares that the quick production of the Liberty engine was a feat that, in his judgment, was "not equaled by anything else done in the war" (3458, 3583). Notwithstanding, the American public became impatient with the delay in securing the Liberty engine. Impossible forecasts were given to the public, which neither knew nor appreciated the details and difficulties in placing a machine with the delicate mechanism and power of an airplane engine in quantity production.

The efforts of the Lincoln Motor Co. at Detroit may be cited as an example. Their contract called for 70 motors per day. The factory required five months for building and included 725,000 feet of floor space. Eighty-eight draftsmen and designers were occupied seven months in designing 6,522 different special tools, of which 91,807 were made and supplied by 89 separate concerns located in different places over the country.

The Liberty engine contains 433 different parts and its total number of parts is 3,397. To make its crank case required 403 gauges and fixtures, 207 cutting tools, and 187 special gauges. To make the connecting rods required 374 gauges and fixtures, 122 cutting tools, and 232 special gauges.

To make a cylinder required 349 gauges and fixtures, 207 cutting tools, and 273 special gauges (3339).

In addition to the normal difficulties of securing and assembling all the tools and equipment required for manufacture were added war conditions, with a shortage of materials, difficulty and delay of shipping, the shortage of labor, and particularly the shortage of mechanics. These considerations should cause the conscientious critic to hesitate before pronouncing inconsiderate and wholesale fault-findings and condemnations.

The Navy depended entirely upon the Liberty motor for the success of its program so far as engines were concerned. From the Army it received 3,482 of these engines during the war. Admiral Taylor declares that the Liberty engine was one of the outstanding features of the war (3526, 3534). The performance of the Liberty engine in driving the naval craft, weighing 28,000 pounds, across the Atlantic without heating or missing a shot, and giving the pilots no trouble, is a demonstration that speaks for itself (3542). The worth of the Liberty engine is demonstrated and conceded (3296, 555-a, 216, 20, 217, 2645, 3084, 560, 561, 12, 2910-CVI, 3595).

The ratio of weight to power in the Liberty engine is practically the minimum known among that class of engines.

Under agreement with the Allies made in the late summer of 1918, the Alles were to jointly bear the expense of producing the Liberty engine in the United States (3082, 3085). Upon final settlement England assumed a liability of $16,599,718 and France $21,272,250 (3084, 555-a).

The Liberty engine was accomplished with the speed of a successful design. It speedily reached production and was adapted to rapid quantity production. Its weight, power, and performance, with its adaptability to quantity production, effected the solution of the allied problem for that kind of an engine.

In our judgment, it is only fair to say that the men who made its success deserve the praise and appreciation due those who perform a splendid service for their country in time of a great war.

The merit of their achievement is not nullified by the fact that good fortune made unnecessary the wide use of the Liberty engine to which it shortly would have been applied by the Allies.

BALLOONS

During the war the United States manufactured 1,036 balloons, including all types for military purposes. Two hundred and seventy-five of these were delivered to the American Expeditionary Forces. Twenty were received from the French by the American Expeditionary Forces, and 35 were furnished by the American Expeditionary Forces to England and France (171, 555-c-d).

MANUFACTURING FACILITIES AT BEGINNING OF THE WAR

No just judgment of America's aircraft efforts during the war can be formed that fails to recognize the difficulties confronting the efforts, our inexperience, or lack of preparation, the withdrawal of over 3,000,000 of America's most virile men from our productive industries, the shortage of material, the difficulties of shipping, that America had never produced a combat plane or a service plane, the inexperienced and hastily assembled personnel that must necessarily be relied upon to conduct our operations, the delay and difficulty in getting accurate information from overseas, the difficulty of adapting their mechanical products to our methods of production-in a word, our unpreparedness (387). This war drew on a greater variety of our resources than any other war in history. America poured out her millions. She paid for airplanes and she thought she ought to have them, but experience and time, both essentials to airplane and engine production, could neither be bought (557).

Revenuly a well-known aircraft manufacturer, when urged to promptly produce 200 planes, stated that the irreducible time in which to prepare his factory for beginning the manufacture was eight months. He referred to a plane whose merits had already been demonstrated (477). Another representative of one of the best established airplane factories in the country said if he were given $5,000,000 and told to go ahead and produce 10 pursuit planes of an absolutely new type, motor and plane, "I would not guarantee I could do it in 18 months or 2 years" (3475).

Admiral Taylor testified:

It was pretty well demonstrated that from the time you started on a plane and engine until that plane could be gotten into production required a year. Although you got a new plane every 2 months, the inception of those planes dated back 8, 10, or 12 months. Also, those planes were comparatively slight modifications of the old plane (3550, 218, 3475, 2910-XVII).

Under war conditions it took one year to get the Browning machine gun in quantity production (477, 21).

A few weeks' investigation by the Bolling Commission in Europe, shortly after we entered the war, convinced them that America could not be of effective help in airplane production before the 1st of July, 1918. Subsequent contracts were based upon that assumption, which proved to be entirely correct (2910-XCVIII).

Col. Gorrell, who was one of the early flyers of the American service, a member of the Bolling Commission, and one of the most thoroughly trained and observant men in our service, states the situation

in reference to our inexperience in the manufacture of service planes and their equipment, as follows:

* * **

Practically everything was not made in America before the war. The instruments were practically all different; the machine guns had to be changed; the synchronizing devices were unknown in this country; ammunition of types that we had never used before had to be obtained; devices such as enlarged drums for shooting and conveniently carrying large quantities of ammunition had to be obtained; wireless equipment unknown in this country was necessary; photographic equipment unknown to his country had to be provided; the bombs, their methods of suspension, the sights for them, well all unknown. In general, you could really say that practically the entire airplane and its accessories and its power plant were unknown in this country (2910XCVIII, 3595-3597).

PRODUCTION STATUS AT ARMISTICE

At the close of the war America had developed some machines that gave promise of splendid success. Gen. Mitchell stated that these machines about to be placed in production "were better than any type he had seen abroad" (17). Among these machines are the Thomas Morse, the Le Pere, the Ordnance Scout, the SE-5, the USD-9-A, the USB-1, the Loening, and the Martin bomber (2634, 3457, 2910LXV, 233, 3606, 2910-LXVIII-V).

* * *

Gen. Mitchell declares the Le Pere to be "an excellent observation ship. It is about 15 miles faster than the De Haviland and maneuvers beautifully, and is very strong and very fine" (2634). He also declares that the U. S. B., which was under contract for deliveries in March, 1919, from the Curtiss Co., "looks very good" as a reconnaissance ship (2634, 3457).

The Curtiss Co. was under contract to deliver 100 of these new machines per day beginning with March, 1919, including the USD9-A (3457).

Seven Le Peres had been manufactured before the armistice and two had been delivered in Europe to the American Expeditionary Forces (3302).

Work on the Loening had started in 1915 and it was in a promising condition at the close of the war. The Loening was a two-place fighter, and on test made a speed of 143 miles an hour. No contracts were made for the manufacture of the Loening before the armistice (2910-LXV, 3609, 3610).

The USD-9-A was a bombing machine and was an improvement over the DH-4 and intended to replace it as a bomber (3609).

The Martin bomber had been tested with successful results. It was the intention to place it under contract for construction when production drawings were completed (3612, 233).

The SE-5, a single-seat pursuit plane, had been placed under contract for training purposes (3613).

AMERICA'S AID TO ALLIES

Some witnesses have expressed humiliation that it was necessary for the United States to purchase airplanes from "bleeding France." Such opinions are based on a narrow, incomprehensive view of the war. America's participation in the war was a joint effort with our allies and obviously could be successfully and rightfully carried on only on a mutual cooperative basis. Wisdom and necessity alike

required that while possibly some burdens of the war could be borne solely by America, others must and should be borne jointly. So it was with airplanes. France was more directly and immediately the victim of the war than America. No true friend of France will complain that America, in going to her relief, paid her for an airplane that she was able to furnish and which she urged America to take, and which America manned for her defense.

At the very beginning of our entry into the war it was agreed that France, with her factories, should be encouraged to supply American airplane needs until that time when we could fulfill our own requireAmerica immediately furnished men to France to fill the positions of men who could be released for work in her factories. (2616). The United States eventually furnished France material enough for over 9,000 engines and 1,800 airplanes. She delivered. over 77,000,000 feet of airplane lumber (the United States being practically the only source of supply). We supplied them with 1,385 engines and with cotton fabric. Likewise, the United States practically furnished all the wood chemicals for airplanes, amounting to thousands of tons. America was a great and final supply depot for allied war need of materials. Large numbers of men for military and auxiliary purposes were supplied the Allies. Something like 15,000 mechanics were maintained in English shops and factories (3293, 3338, 226, 227). In fact, without the aid of America in men, and particularly in materials, there would have been a complete failure of the allied air program (556, 386).

It may freely be confessed that the United States was greatly disappointed in failing to reach that degree of efficiency and success in aircraft that she so much desired. She hoped, and was lead to believe, in the impossible. At the time she was in the war, handicapped by remoteness and the greatest intervening difficulties that have ever impeded a Nation in successful action, she failed to reach that brilliant and monumental success in the Air Service that would have been hers had the war continued another year. Nevertheless, a just judgment of her efforts will credit America with a very great and material contribution in aviation and to allied supremacy in the war. To a large extent her efforts consisted of homely, grinding, patient industry, seeking by tremendous effort to briefly overcome the inexperience and lack of preparation of the preceding 20 years of neglect. She laid the foundation and approached the final effective climax of her zeal and industry when the fortunate early termination of the war deprived her of the dramatic concluding chapter of her achievements.

AVIATION RESULTS AT THE FRONT

The first participation of American pilots in the European war was in association with the allied forces. The first American pursuit squadron went over the lines on the 14th day of April, 1918 (2910LXXXI). On the day of the armistice 757 American pilots and 481 observers were on the front (551).

For some months prior to the armistice the predominance of the allied air forces over the enemy was constantly increasing. On the 11th of November 1918, the Allies had on the front 6,784 planes and the enemy 3,352 (3304). On the first day of the Argonne battle there were 842 planes under the American command and 350 under