(6) PLANE SURFACES.

It is desired to avoid surfaces too large to satisfy conditions 3 and 8, but the plane surfaces should be of sufficient area and of such design as to permit a safe range in the angle of attack and to insure safe gliding with the power shut off.

It is desirable to have the fabric secured so as to allow replacement of ribs without removing the stanchions or struts, if practicable, without interfering with interchangeability of parts. All hinges should be in plain view.

(7) FULL LOAD.

The "full-load capacity is designated as fuel and oil sufficient for a flight of four hours and (x) pounds in addition; i. e., x should include 350 pounds for two persons, and (y) pounds for wireless and other apparatus. As the "fullload" capacity depends to a great extent upon the lightness of structure, the weight and efficiency of motor, manufacturers are requested to state the "full load"; i. e., the value of x, which they can guarantee.

(8) SPEED AND ENDURANCE.

The maximum speed must be at least 55 miles per hour, with full load, and during a 4-hour test, starting with full load, it must average at least 50 miles per hour.

A considerable range of speed is desirable, and manufacturers are requested to state the minimum speed at which the machine will fly with full load.

(9) PERFORMANCE TESTS.

The maximum and minimum speed tests will each be the mean of 10 runs over a measured mile, 5 before the wind and 5 against the wind.

The endurance test will be made over a convenient triangular circuit of at least 5 miles, to be selected, the speed being recorded by a tested recording anemometer, read before the start and again at the end of the flight.

The machine will be required to rise from the water with full load in a dead calm during a run of not more than 1,000 feet, to turn with full load, without skidding, stalling, or sliding, in a circle of 400 yards diameter; to climb at the rate of (x) feet per minute, on leaving the water, to an altitude of 1,500 feet in a spiral ascent, which will include at least one complete turn; and to glide, with power shut off, from an altitude of 500 feet to a landing on the water throughout a horizontal distance of at least 2,500 feet, or throughout a distance greater in the same proportion if the power be cut off at a higher altitude.

(x') It is desired to accomplish a rate of 100 feet per minute, but to avoid the use of very large surfaces a lesser rate may be satisfactory. Manufacturers are requested to indicate the rate of climb (the value of x1) which they can guarantee under the conditions of this test.

(10) THE POWER PLANT.

Manufacturers may use engines and propellers of any known make, although an air-cooled motor is regarded as preferable. The power must be self-starting from the seat of one operator and controllable by either operator, with gear and bracket for driving a generator for wireless apparatus and provided with a removable muffler that will not reduce the power below that necessary to fly, at the maximum speed required, with one person for one hour.

It must be provided with gauges for gas and oil and with one tachometer in plain sight of the operator, and it must be capable of throttling down to run at reduced speed.

Special consideration will be given to any efficient motor operated by fuel oil or any fluid that is not dangerous to carry on board ship, an extra price or premium being contemplated for the purchase of a satisfactory motor of this character.

(11) GENERAL REQUIREMENTS.

All features of mechanical construction must be of first-class workmanship and design throughout.

Proper protection from weather and spray must be provided for all parts by the use of suitable paints, varnishes, shields, or nickel plating. If the metal

"cupror" be used, or if suitable "monel metal" be used, no protection will be required.

The color scheme should be of the standard Navy gray or "war color," the use of black being permitted for steel or other metallic parts whenever the protection may be improved thereby. This color, however, will not be required for the fabrics if it can be shown that there is a gain of efficiency by using any other.

(12) MOUNTING OF INSTRUMENTS.

Suitable mounting is required for a standard chart roll (10 inches by 12 inches), a standard compass in a box (10 inches by 10 inches), an anemometer or speed indicator, an inclinometer, and an altimeter. The above instruments will be furnished by the Government, but it must be possible to mount them convenient for observation by the pilots.

In addition, a horizontal space of 11 inches by 11 inches must be allowed for the wireless apparatus, convenient to one of the operators.

(13) SPARE PARTS AND DATA.

A list of spare parts to be provided should accompany each tender and include a suitable transporting or launching truck.

Complete stress diagrams, showing the distribution of loads on all the main structural parts, including the distribution of loads during the 400-yard turn. under full load conditions, should be furnished with complete statements of the dimensions and material of each part. Adequate ratio of breaking load to working load should be shown. Unsatisfactory features of machines contracted for should be subject to correction to the satisfaction of the Government representatives.

The location of the center of gravity in full load and in light loads condition must be shown, together with diagrams showing the location of the center of pressure for the extreme positions within the range of the safe angles of attack.

The general arrangement and detail plans of all complete machines contracted for will be required on acceptance.

(14) INSPECTIONS AND TESTS.

Throughout the construction of machines contracted for, designated Government inspectors shall have complete and free access to the plans and shops and to records of tests and materials. Whenever such inspector may deem it necessary, supplementary or additional tests shall be made by the builder as required.

The acceptance trials shall be conducted by representatives of the contractor under the supervision of designated representatives of the Government at such times and places as the Government may direct.

(15) SEPARATION OF COST ITEMS.

Designs submitted should have the estimated cost of the architectural features separated from the cost of the power plant and other machinery.

Mr. ROBERTS. You spoke of some pieces of apparatus being taken to San Diego for testing. Is the Navy carrying on much of this experimental work at San Diego?

Capt. CHAMBERS. No: not at all; the Army has gone there. We were there last winter, but have sent our whole outfit down to Guantanamo to operate with the fleet. It was sent down by collier on December 29, and the most of the officers went down the 6th of January with the fleet.

Mr. ROBERTS. Where do we carry on the naval experiments and tests on shore, out here at College Park?

Capt. CHAMBERS. No; at Annapolis. I think it best now to separate the experimentation part of the work from the instruction part and hope to have all experiments made at the Washington Navy Yard in the future.

Mr. ROBERTS. Have you stated how many officers we have now in this work; I mean, actually operating machines?

Capt. CHAMBERS. There are eight qualified. We have had three other officers ordered for instruction. My object in sending the machines down to Guantanamo more than anything else was to have them near the fleet to have the officers to instruct. Almost as soon as we sent the machines there three submarine officers applied for instruction in addition to their other duties.

Mr. ROBERTS. What do you do with these officers after they become qualified for aviation, let them go back to their ships?

Capt. CHAMBERS. Yes; and I expect to have certificates of qualification issued to them.

Mr. ROBERTS. Would it not be a desirable thing to have an aviation corps, the men qualifying to devote their whole time to this work; that is, after they become qualified for aviation to continue in that line of work?

Capt. CHAMBERS. I have rather been inclined against that idea. I think we ought not to have any more corps if we can avoid it.

Mr. ROBERTS. I do not know as I would establish a separate corps, but a sort of reserve corps, say, to have a body of men for that purpose. It occurs to me that if you have a man qualify as an air pilot, or whatever you may term him, to pilot a flying machine that is in use to-day and he goes back to his post, and to-morrow or next day or next week a new type of flying machines comes into use, that he will not be capable of going right into service. Will he or not under such circumstances as I have outlined?

Capt. CHAMBERS. Probably. I want to see them tried under our present conditions first. I do not want to advance some new scheme before trying this. Under the present scheme we can always get aviators, and the other scheme we would not always get them. Under the present scheme the battleship is right at hand and ready for the avitator to use the machine.

We expect to get more aviators by this method, as the fleet will provide plenty of officers and mechanics of the right sort and all the facilities for repairs. In this way the work will be carried on right under the eyes of all the officers and men. Regular routine practice will make the whole Navy as familiar with the machines as with boats and guns. In the shortest possible time competition between. ships and routine practice will result in efficiency and produce many practical hints for improvement.

On the other hand, a separate corps would require additional officers at much greater expense and require more special ships. It has been the experience that aviators should be comparatively young and should not be compelled to operate continuously for many years. Those who have had the practice becoming a reserve, under a separate corps the number of aviators would naturally be restricted. It would be a sort of continuous job. and the reserve might be too antiquated to be of much use during the supreme test.

Mr. ROBERTS. You are keeping closely in touch with aerial navigation all over the world. I presume?

Capt. CHAMBERS. I try to.

Mr. ROBERTS. Maybe you have gone into this already, and if so, I will not pursue it, but I will ask what is being done now in the way of carrying a body of men in an airship of some kind-and I do not

mean a dirigible, but a flying machine-a heavier-than-air machine. Has there been any development to speak of along that line?

Capt. CHAMBERS. Nothing that I know of in an official way. You see a number of reports now and then in the press of what has been done in a sporting line or civil way. You will see machines that have been developed to carry a dozen people for the sake of the advertise

ment.

Mr. ROBERTS, I have read in some journal, I think devoted to flying machines, that the French Army had developed a machine that would carry, my recollection is, something like 18 or 20 men.

Capt. CHAMBERS. They have already carried 13, and may possibly in the future carry a greater number, but nothing of any consequence has been done in that line yet. The most of it has been done for exhibition purposes, for commercial and development purposes, and only in case of short flights. The fact is not generally stated that the flight taken was comparatively short. However, two and three passengers have been carried on some very long flights.

Mr. ROBERTS. Well, if they are now carrying a number of people a short distance there is no telling what they will be able to do next year or the year after?

Capt. CHAMBERS. Aviation is yet in its infancy, as I stated, and this lusty infant industry needs a bit more of nourishing than it is getting now in the land where it first saw the light.

Mr. ROBERTS. It was only a year or so ago that the Wrights were making short flights at Fort Meyer?

Capt. CHAMBERS. Certainly, and the advance in aviation in all directions is wonderful. Aviators are now ascending 18.000 feet where the Wrights went up a few hundred feet only, a few years ago.

The CHAIRMAN. You say they have reached to a height of 18,000 feet?

Capt. CHAMBERS. Yes; and the altitude record for dirigibles is about 8.000 feet.

The CHAIRMAN. I did not know they had gone above 14.000 feet. Capt. CHAMBERS. More than that; Legagneau went up 18.600 feet on September 17, using an oxygen tube to assist respiration, but on December 11, Garros went up to 19,032 feet, about 3.6 miles. Garros also flew recently from Tunis in Africa to Rome, by way of Sicily, stopping at places en route, in four days. And we have had Janis flying from Omaha to New Orleans, and so on, following the water, a distance of

Mr. ROBERTS (interposing). Is there very much thought being given now to transporting a considerable number of men?

Capt. CHAMBERS. I do not think so at present. I think it a little. early to do that, but it will undoubtedly come in time. As means of transport for large bodies of men the dirigible only can be regarded seriously at present. Aeroplanes have carried 8 or 9 men (on one occasion as many as 13 small people) for short distances and comparatively low. Landing the aeroplane with much heavy extra weight is still hazardous, but dirigibles already transport 30 men on regular trips for hours at a time. A fleet of them used as transports might become a serious menace unless opposed by ships or properly equipped and more numerous aeroplanes. Press accounts state that a corporation of Berlin financiers are interested in a colossal dirigible 787 feet long designed to carry 300 passengers, but I understand this

monster exists, as yet, on paper only. In October a Zeppelin dirigible 450 feet long went 1,200 miles in 30 hours with 21 passengers on her trial trip.

Mr. ROBERTS. What part is getting the greatest consideration now, stability of the machines?

Capt. CHAMBERS. I think so. of my attention to that point.

I know that I am devoting the most

Mr. ROBERTS. Are they devoting much attention to speed? Capt. CHAMBERS. Oh, yes; speed is what wins races, and that is what has developed aviation at such a rapid pace. The speed machine as it is built has a very small surface; it must be small. They have practically reached the limit for a while, because they have to come down, they have to land, and they have to land at the speed at which they can fly, and when they land at that speed they are apt to break the machine all to pieces. Until they can develop a machine that will not only fly at a rapid rate of speed and at the same time at a lower rate of speed for landing purposes, they will be stopped in that line of development for awhile.

The CHAIRMAN. Do they not land at a lower rate of speed than they fly at?

Capt. CHAMBERS. Not the racing machines. They have got their surface so small that they have to land at about the speed they use in flying.

The CHAIRMAN. I was under the impression that when up in the air they went at a very rapid rate of speed, and then before landing they cut off the power and would circle around and come down at a reduced rate of speed.

Capt. CHAMBERS. No: they do cut off the power, but they have to come down at a speed that will support them in the air; and that is the way we happened to lose the last race when the Frenchman won it. He had taken the step-by-step process to get himself acquainted with landing in different machines at various speeds. Our men had been flying in machines at 60 or 70 miles an hour and not at 110 miles an hour. We did not have any aviators that could fly in such fast machines. It is a matter of great skill to fly one of those machines and come down to land without danger of smashing it all to pieces. Mr. ROBERTS. I supposed that when they landed with those machines they cut off the power and did what is called voloplaning. Capt. CHAMBERS. Yes; the power may be cut off high up, but you can voloplane at any speed you desire, according to what angle you set your machine to fall at. It is gravity that does the work. You can at the proper angle come down at the speed necessary for sustentation, and that is the speed that will support you when you turn horizontally to land; but you have got to be very careful to prevent smashing your machine.

The CHAIRMAN. But what if he hits the ground at the rate of 110 miles an hour?

Capt. CHAMBERS. He does not do that. He comes down, and when he gets very near the ground, near enough to enable him to make the turn and stop the machine, then he gets slower, but the machine goes a long distance afterwards. It would not do to stop his machine in the horizontal position at any elevation up in the air. If he did he would come down like a shot.