"Mark James Boyd" wrote in message
news:405766f7$1@darkstar...
Tony Verhulst wrote:

This is a good point. The Skylane that I own a small piece of has a horn
that sounds about 10 kts before the actual stall - and as such, is
pretty useless, IMHO.

I've had the horn in a Cezzna save me twice. Both times
at max gross, once on takeoff on a hot day, once on a night
IFR missed approach. I didn't think it could happen to
me. It did. Four people are alive and well because somebody
decided a stall horn was a good idea. I'd like to find that
guy, thank him, and buy him dinner.

The excellent point that an AOA indicator is the simplest and
most effective way to detect oncoming stall was very well
pointed out by the poster who mentioned ballast. Very different
airspeeds with ballast vs. without, and not something easily
computed. Wind shear is another circumstance where AOA indications
are much faster and easier to interpret than airspeed and/or pitch.
There are some dusk wind shear glider fatalities where I believe an
AOA or stall horn would have saved the day.

Dick Johnson feels that a properly designed stall warning works in
gliders. He knows more than I.

I agree.

I did have a twinge from the poster who said like
pavlov's dog, one can become reliant on the horn. Then if it
fails, one is out of luck. I dunno, I guess having the horn
go off a bunch of times and doing the right thing is
cheaper than hiring an instructor. Maybe one can learn
enough along the way so that when the horn fails, one can still
avoid the stall...

Still, the Pavlov comment was a good one and got me thinking...

In a power plane, checking the stall horn is part of (most)
preflights. Most power planes require a stall horn as part of
the type certification. I suppose you could check it as a
mandatory part of the pre-flight in a glider too, and perhaps
use a "harmonica" style so it didn't use electrics.

Or use the string AOA idea. I'd like to see this work. I'm
not so keen on having something else the pilot has to
LOOK at (vs. hearing). But who knows, and it's a fun
experiment...
--

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Mark Boyd
Avenal, California, USA

I'm not sure I buy the Pavlov argument. These are warning systems we are
talking about and, if the glider is flown the way it is supposed to be
flown, they will never be heard. They should sound only under extraordinary
circumstances when the pilots self-discipline has failed.

I'd be really concerned about a pilot who always waited for the gear horn
before remembering to put the gear down. I was always taught that if I hear
a warning horn, I've already screwed up. Strive to fly so you never hear
one. (Except for that dratted Cessna stall horn sounding in the flare.)

Bill Daniels