"John Gaquin" wrote in message
. ..

"Jon Kraus" wrote in message newsBm%g.17816

5 or 10 knots? What are they freakn' barn doors or something? :-) Sure
your not fibbing?

Sometimes cowl flaps can really disrupt airflow. On the DC3, the cowl
flaps have 3 positions: open, closed, and trail (controlled, btw, by a
pair of round valve handles that look for all the world like they were
borrowed from a steam locomotive). Open,they really stick out all around
the cowling, and in trail, they are pretty much closed, but will stay open
a bit as needed. Cowl flaps are an item on the pretake-off check. If you
try to take off with them in "open", it will set up a hell of a buffet.

You wouldn't believe the drag on a P47 Thunderbolt with the cowls open.
Don't know about the D models, but on the N, you can easily use them as a
speed brake :-)) Also, taxiing with them open just about totally blinds you
in front of the airplane....not that the visibility is all that great in
front with them closed :-))
Dudley Henriques