Peso - SF Fleet Week '09

John Sessoms jsessoms002 at
Sat Oct 24 14:21:38 EDT 2009

From: gldnbearz
> The weather went against the Blue Angels this year.  Saturday's
> airshow was canceled about 10 minutes in due to poor visibility.
> Sunday was still quite overcast.  We decided to chance the weather and
> another cancellation to venture out.
> While waiting for the Blue Angels, we saw:
> Then Fat Albert flew out:
> Can someone explain to me the effects the propellers are causing?
> Looks rather neat.

Cavitation - there's a pressure drop at the trailing edge of the blade 
most noticable near the tip.

If the air has enough moisture water vapor condenses there and is blown 
aft by the forward motion of the aircraft.

Since the blade tips are rotating, the condensation blowing aft takes on 
a spiral form.

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