limit of trim = limit of travel?

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

On 2008-04-28, Stealth Pilot wrote:
$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.

That's the difference between a certified aircraft (the Cessna) and an
experimental/amateur built (where you don't have to use approved parts,
just a part fit for purpose).

--
From the sunny Isle of Man.
Yes, the Reply-To email address is valid.

"Dylan Smith" wrote in message
...
On 2008-04-28, Stealth Pilot wrote:
$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.

That's the difference between a certified aircraft (the Cessna) and an
experimental/amateur built (where you don't have to use approved parts,
just a part fit for purpose).

--
From the sunny Isle of Man.
Yes, the Reply-To email address is valid.

This is an interesting issue, and the real answer is not necessarily
intuitive. In a type certified aircraft, the switch would need to be have
appropriate paperwork with a chain of custody attesting that it meets the
appropriate standards; and may need to be installed by an airframe mechanic.

I have been away from that industry for about twenty years, so some of the
regulations have changed, and was a radio repairman (rather than a mechanic)
at the time. However, for anyone operating a type certified aircraft, who
really wants to know the "straight and skinny" on this sort of issue, the
place to start in the USA is your local FSDO--before you do anything to the
aircraft. Ask for the Safety Program Manager for Airworthiness and he
should be able to point you to the correct office and/or litterature.

The point is that a common electrical part probably does not need to come
from the airframe manufacturer; but it is not "free stock" either. However,
don't be surprised if the airframe manufacturer turns out to be the best and
most economical source--when I was a radio repairman, the avionics
manufacturers were frequently the best and most economical sources of
standard parts for their equipment.

Peter

Peter Dohm writes:

... when I was a radio repairman, the avionics
manufacturers were frequently the best and most economical sources of
standard parts for their equipment.

So how did the other sources (if there were any) stay in business?

On Apr 28, 9:36 am, Stealth Pilot
wrote:

$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

Works for a Tailwind, a homebuilt. Ain't legal in a certified
airplane, since the regs demand that the parts as listed in the
manufacturer's parts manual be used, and they know that, so they
charge lots for them.
So that's why my own airplane is a homebuilt.

Dan