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Old March 5th 09, 04:53 AM posted to rec.aviation.misc,rec.aviation.homebuilt
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Default Stall Warning - AofA

On Mar 1, 10:12 am, Brian Whatcott wrote:

It was not everyone's cup of tea, I don't suppose: in particular, that
mouth to wing actvity was eliminated by a small vane on a microswitch,
which howled when the vane pushed up at high AofA. I think that was a
C172 mod wasn't it? It needed power to work though.


The 172's also used the sucker horn. The microswitch was a earlier
iteration on smaller Cessnas and was used much later on faster
singles.
The reed for the horn is one of the cheapest parts you can buy from
Cessna. Last batch I bought were something like 47 cents apiece. But
then, some of them didn't work and took a little dorking with the reed
to get them to squeak properly.
If there are ANY leaks in that system it won't work. Common leakage
is at the wing's leading edge skin-to-hose fitting interface, where
there's a small plate (with the slot in it) sandwiched between the two
that's adjustable for stagnation point so the 5-10 kt thing can be
adjusted. The hose fitting is plastic and cracks, too, and Cessna more
than makes up for the low reed price by charging bigtime for the
fitting.

Dan