‘The machine, with its new curvature, never failed to respond promptly
to even small movements of the rudder. The operator could cause it
to almost skim the ground, following the undulations of its surface,
or he could cause it to sail out almost on a level with the starting
point, and, passing high above the foot of the hill, gradually settle
down to the ground. The wind on this day was blowing eleven to fourteen
miles per hour. The next day, the conditions being favourable, the
machine was again taken out for trial. This time the velocity of the
wind was eighteen to twenty-two miles per hour. At first we felt some
doubt as to the safety of attempting free flight in so strong a wind,
with a machine of over 300 square feet and a practice of less than
five minutes spent in actual flight. But after several preliminary
experiments we decided to try a glide. The control of the machine
seemed so good that we then felt no apprehension in sailing boldly
forth. And thereafter we made glide after glide, sometimes following
the ground closely and sometimes sailing high in the air. Mr Chanute
had his camera with him and took pictures of some of these glides,
several of which are among those shown.
‘We made glides on subsequent days, whenever the conditions were
favourable. The highest wind thus experimented in was a little over
twelve metres per second--nearly twenty-seven miles per hour.
‘It had been our intention when building the machine to do the larger
part of the experimenting in the following manner:--When the wind
blew seventeen miles an hour, or more, we would attach a rope to the
machine and let it rise as a kite with the operator upon it. When it
should reach a proper height the operator would cast off the rope and
glide down to the ground just as from the top of a hill. In this way we
would be saved the trouble of carrying the machine uphill after each
glide, and could make at least ten glides in the time required for one
in the other way. But when we came to try it, we found that a wind
of seventeen miles, as measured by Richards’ anemometer, instead of
sustaining the machine with its operator, a total weight of 240 lbs.,
at an angle of incidence of three degrees, in reality would not sustain
the machine alone--100 lbs.--at this angle. Its lifting capacity seemed
scarcely one-third of the calculated amount. In order to make sure that
this was not due to the porosity of the cloth, we constructed two small
experimental surfaces of equal size, one of which was air-proofed and
the other left in its natural state; but we could detect no difference
in their lifting powers. For a time we were led to suspect that the
lift of curved surfaces very little exceeded that of planes of the same
size, but further investigation and experiment led to the opinion that
(1) the anemometer used by us over-recorded the true velocity of the
wind by nearly 15 per cent; (2) that the well-known Smeaton coefficient
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Elsewhere in the archive
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account