On Sun, 27 Apr 2008 10:39:26 -0700 (PDT),
wrote:

On Apr 26, 3:56 pm, Buttman wrote:

"supposed to", but doesn't always. I've flown planes (especially cessnas
with their crappy cereal-box-toy-quality plastic stall horns) that don't go
off at all, but will test fine on the ground.

That's not hard to fix. The plastic fitting inside the leading
edge cracks and leaks. Sometimes the sun's heat warps and shrinks the
fitting so that it no longer seals against the LE and leaks at that
point, too. Any leakage will kill the horn. The horn itself has a
little replaceable reed in it, costs something like 79 cents from
Cessna. And I think that leaky cabin doors sometimes have something to
do with it; the horn uses suction to drive it, and a leaky door (among
other things) can drop the cabin pressure a little, reducing the
differential so that the horn doesn't sound well. The older and better
system (still used on more expensive Cessnas and other airplanes) has
the vane that works a $300 microswitch assembly to fire an electric
horn. The microswitch gets dust in it and doesn't contact properly, so
you soak it in some brake cleaner or isopropyl and blow it out,
clicking it all the while.

Dan

$300 ????????????

the microswitch in my Tailwind cost $1.25 from Tandy. it is held in
with tape to make a jamb fit.
been working perfectly for 300 hours flying.

Stealth Pilot