SECRETARY LANGLEY’S INSTRUCTIONS TO ASSISTANTS
SMITHSONIAN INSTITUTION, WASHINGTON, D. C., November 30, 1895.
DEAR SIR:
The following instructions are to replace those of May 13, 1895:
1. The minimum fraction of its own “flying weight” (that is, weight complete with initial water and fuel), which the aerodrome shall lift on the pendulum, is 50 percent,[50] under such engine power as can certainly be gotten up in the field and maintained during forty seconds from the time the aerodrome is let go.
The blast, the pumps, and all other essential parts must, in other words, be in such a condition that steam enough for this lifting over 50 per cent of weight can be gotten up readily and surely in the field and in a time which will still leave at least forty seconds’ supply.
2. The minimum relation of supporting area to weight in any aerodrome constructed hereafter, is to be two feet to the pound,[50] and the minimum of power at the rate of one steadily-maintained horse power[50] at the brake under ordinary conditions, to not over twenty-two pounds (ten kilos) of flying weight. In absence of a brake determination horse power may be taken—
H. P. =
These rules do not apply to No. 5, but they do to No. 6, which is to be built over, if necessary, to meet them.
3. In balancing an aerodrome, unless otherwise instructed, set wings at a root angle of either 10°, 7°, or 5°, after being certain from previous inversion and sanding, that the tip angle in motion will not differ from this root angle as much as 5°.