Ok - you've got a point :-)

--
Bert Willing

ASW20 "TW"


"Derek Copeland" a écrit dans le
message de news: ...
Bert Willing wrote on 12th July.
You're point number two doesn't hold: At constant speed (whichever speed),
a

wing of a sailplane will never produce more lift than corresponds to the
weight of the glider. Otherwise you would be climbing.

Your main original point is absolutely right.
--------------------------------------------------------------

Er, I'm only a humble gliding instructor, so what do I know about things?

You are also right in that in steady flight lift must equal the weight of
the glider. However in a spiral dive you are in accelerated flight and the
glider could effectively weigh several times its own weight, and the wings
(if not stalled) have to produce the equivalent extra amount of lift to
balance this. If you are pulling more than 3.5 g at high speeds, opening
the
airbrakes could just be enough to finish things off, due to the extra
bending load on the wings this entails. The correct recovery from a
spiral
dive is just to carefully reduce the angle of bank while keeping the stick
fairly well back, by the way.

As an instructor I do lots of spins and spiral dives, so can easily
recognise what is going on. Many good cross-country pilots haven't done
either for years, so could be caught out should either occur unexpectedly
.
The recovery actions are quite different. I also understand that Nimbus 4s
have a non-standard spin recovery procedure, which further complicates the
issue.

Derek Copeland


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