not the same thing ---not even remotely the same thing
your heli tho -aside from heat losses --should work to see what is happening --if the box is big enough - make one side from Mylar to see it .
Go for it - whenever in doubt --test it.
Just like flat airfoils -- having tested em - for some apps they are the best
Oh yeh -the rocket - as long as it is tied to the cart and the REACTION is unidirectional why should it move ?