Re: Fw: Dinosaurs and birds

[Michael Habib <mhabib5@jhmi.edu>]

> I'd say that ground-up scenarios that don't presuppose an increase in 
> maximum running speed due to flapping are also feasible and even 
> likely. Transient gusts play a huge role in assisting ground up flight 
> scenarios, and they don't even need to be substantial gusts.  Lift 
> increases with the square of the gust speed, so even a 40% gust speed 
> will temporarily double available lift, and the animal can then use 
> gravity to accelerate and maintain that lift while returning to the 
> ground.  Running speed isn't terribly important to the ground-up 
> flight scenario.  I believe that this is pretty much what Mike thinks 
> as well, but I don't want to put words in his mouth.
> JimC

That is indeed very much what I think, as well.  Gust utilization also 
carries the advantage of not requiring a hefty upstroke ability or 
overall power for moving the wings, which is important because these 
factors both seem to be pretty delayed in the evolution of avian flight.

Cheers,

--Mike H.