Robin feathers for extra lift cloche

Sopwith has a dream, one day, if he is clever and courageous, in equal measures, he wants to be a bat.
He has made himself a beautiful set of aerodynamic wings and just to be on the safe side he has invented the, soon to be world famous, patented "tail activated parachute".
The plan is to bravely leap from increasingly high objects, until he soars off into the blue yonder with a victory squeak.
Today he has added robin feathers for extra lift.
Every adventure has to start somewhere and so, with goggles on, final checks completed, its ......."Chocks away!"
If this doesn't work, don't worry. With Sopwith's determination and ingenuity, one day he is very likely to invent some means of flying.