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Their Own Words
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.
SIGNAL CORPS SPECIFICATION NO. 486.
ADVERTISEMENT AND SPECIFICATION FOR A HEAVIER THAN-AIR
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
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.
This specification cavers the construction of a Flying machine supported
entirety by the dynamic reaction of the atmosphere and having no gas
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.
The Government reserves the right to inspect any and all processes of
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
(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:
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
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,
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
Brigadier General, Chief Signal Officer of the Army
WASHINGTON, D. C. December 23, 1907.