


Do not try this at home
A daredevil is planning, as a stunt, to
jump/fly horizontally across a canyon. He will be carrying a wing that has a chord of 1 m, a total length of 10 m and a profile
with an angle of zero lift equal to 5°. The wing will be mounted at an angle of attack of 16°, for which it is known
that the lift on the (finite) wing can be estimated by using the thin airfoil theory and assuming elliptical lift distribution.
The profile drag coefficient on the wing is 0.015. The frontal area of the daredevil's body, including all carried accessories,
would be 0.40 m^{2} and his drag coefficient can be estimated as 1.5. It can be assumed that the wing is responsible
for the entire lift and that the total drag can be estimated by adding the drag on the wing to that on the daredevil. The total
mass of wing and man is 100 kg. Thrust for the jump will be provided by a small rocket and the daredevil will be using roller
skates to reduce friction on the runway. Compute the required thrust of the rocket (assumed constant during the jump) and the
takeoff speed. Explain whether the daredevil would reach the other side if he lowered the takeoff speed computed above but
increased the thrust; sketch a likely trajectory.
Contributed by Stavros Tavoularis,
Department of Mechanical Engineering, University of Ottawa, Ottawa, Canada. Image from JetMan Project 
