I am considering a parachute on a 7Kg (15lb) UAV.
I have found various formulas on the web, but the question is what parameters to use.
What rate of descent should I choose so that, after a parachute landing, a well built but not overweight UAV will be able to fly again after straightening the undercarriage and minimal repairs?
My guess would be 3 metres per second (10ft/s) but I have no real experience. My calculations indicate such a hemispherical parachute would need to be 5 metres (16ft) in diameter, which would need 40 square metres (430 squ ft) of material - which is huge, and does not seem right.
I would appreciate any useful information. Jack.