Signal Corps Specification No. 486

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No. 486
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In Their Own Words

n 23 December 1907,  the Signal Corps of United States Army issued specifications for a heavier-than-air flying machine. A copy was sent the the Wright brothers on 3 January 1908. It was widely believed that these specs were written with the Wright airplane in mind, but this is only partly true. The specs reflected what the Wrights had told Lt. Frank Lahm they could provide when he talked to them in France. When the specification was issued, the Wrights had yet to accomplish some of its key requirements. Specifically, their airplanes had never carried more than one person, they had never flown more than 35 miles per hour, they had never traveled more than 24 miles in a single flight, and they had never trained anyone else to fly their airplane. But the Wrights signed the contract, biting off more than they had ever chewed before and with only six months to chew it.



To The Public:

Sealed proposals, in duplicate, will be received at this office until 12 o'clock noon on February 1, 1908, on behalf of the Board of Ordnance and Fortification for furnishing the Signal Corps with a heavier-than-air flying machine. All proposals received will be turned over to the Board of Ordnance and Fortification at its first meeting after February 1 for its official action.

 Persons wishing to submit proposals under this specification can obtain the necessary forms and envelopes by application to the Chief Signal Officer, United States Army, War Department, Washington, D. C. The United States reserves the right to reject any and all proposals.

 Unless the bidders are also the manufacturers of the flying machine they must state the name and place of the maker.

 Preliminary. - This specification cavers the construction of a Flying machine supported entirety by the dynamic reaction of the atmosphere and having no gas bag.

 Acceptance. - The flying machine will be accepted only after a successful trial flight, during which it will comply with all requirements of this specification. No payments on account will be made until after the trial flight and acceptance.

 Inspection. — The Government reserves the right to inspect any and all processes of manufacture.

 The general dimensions of the flying machine will be determined by the manufacturer, subject to the following conditions:

 1. Bidders must submit with their proposals the following:

(a) Drawings to scale showing the general dimensions and shape of the flying machine which they propose to build under this specification.
(b) Statement of the speed for which it is designed.
(c) Statement of the total surface area of the supporting planes.
(d) Statement of the total weight.
(e) Description of the engine which will be used for motive power.
(f) The material of which the frame, planes, and propellers will be constructed. Plans received will not be shown to other bidders. 

2. It is desirable that the flying machine should be designed so that it may be quickly and easily assembled and taken apart and packed for transportation in army wagons. It should be capable of being assembled and put in operating condition in about one hour.

 3. The flying machine must be designed to carry two persons having a combined weight of about 350 pounds, also sufficient fuel for a flight of 125 miles. 

4. The flying machine should he designed to have a speed of at least forty miles per hour in still air, but bidders must submit quotations in their proposals for cost depending upon the speed attained during the trial flight, according to the following scale:

40 miles per hour, 100 per cent.
39 miles per hour, 90 per cent.
38 miles per hour, 80 per cent.
37 miles per hour. 70 per cent.
36 miles per hour, 50 percent;
Less than 36 miles per hour rejected.
41 miles per hour, 110 per cent.
42 miles per hour. 120 percent.
43 miles per hour, 130 per cent.
44 miles per hour. 140 per cent. 

5. The speed accomplished during the trial flight will be determined by taking an average of the time over a measured course of more than five miles against and with the wind. The time will be taken by a flying start, passing the starting point at full speed at both ends of the course. This test subject to such additional details as the Chief Signal Officer of the Army may prescribe at the lime.

 6. Before acceptance a trial endurance flight will be required of at least one hour during which time the flying, machine must remain continuously in the air without landing. It shall return to the starting point and land without any damage that would prevent it immediately starting upon another flight. During this trial flight of one hour it must be steered in all directions without difficulty and at all times under perfect control and equilibrium.

 7. Three trials will be allowed for speed as provided for in paragraphs 4 and 5. Three trials for endurance as provided for in paragraph 6. and both tests must be completed within a period of thirty days from the dale of delivery. The expense of the tests to be borne by the manufacturer. The place of delivery to the Government and trial flights will be at Fort Myer, Virginia.

 8. It should be so designed as to ascend in any country which may be encountered in field service. The starting device must be simple and transportable. It should also land in a field without requiring a specially prepared spot and without damaging its structure.

 9. It should be provided with some device to permit of a safe descent in case of an accident to the propelling machinery.

 10. It should be sufficiently simple in its construction and operation to permit an intelligent man to become proficient in its use within a reasonable length of time.

11. Bidders must furnish evidence that the Government of the United States has the lawful right to use all patented devices or appurtenances which may be a part of the flying machine, and that the manufacturers of the flying machine are authorized to convey the same to the Government. This refers to the unrestricted right to use the flying machine sold to the Government, but does not contemplate the exclusive purchase of patent rights for duplicating the flying machine.

 12. Bidders will be required to furnish with their proposal a certified check amounting to  ten per cent of the price stated for the 40-mile speed. Upon making the award for the flying machine these certified checks will be returned to the bidders and the successful bidder will be required to furnish a bond, according to Army Regulations, of the amount equal to the price stated for the 40-mile speed.

 13. The price quoted in proposals must be understood to include the instruction of two men in the handling and operation of this flying machine. No extra charge for this service will be allowed.

 14. Bidders must state the time which will be required for delivery after receipt of order.

JAMES ALLEN, Brigadier General, Chief Signal Officer of the Army
WASHINGTON, D. C. December 23, 1907.

The contract that the Wright brothers signed with the US Army, including Signal Corps Specifications No. 486. Page 1.

Page 2.

Page 3.

Page 4.

Brigadier General James Allen, who issued Signal Corps Specification No. 486, is remembered for being exceptionally progressive during the years he headed the Signal Corps.

Major George Squier, who actually wrote the specification, became the first military officer to fly.  On 12 September 1908, he was Orville Wright's passenger. Later, he became head of the Aviation Section, US Signal Corps – the forerunner of the US Air Force.

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