<<Every general aviation old timer goes into cardiac arrest when you talk
about
using automobile parts in an airplane.......They make these things as good
as they reasonably can to prevent warranty
problems.>>

Good comments - I find the discussion always interesting as some people
think that nothing but airplane parts belong in airplanes.  Parts is parts
and they don't know where they were "intended" to go.  Some car parts are
lots better than airplane parts and a lot of the time it just doesn't make
any difference.  I look at a lot of the fasteners on plastic airplanes - a
high-strength #6 or #8 screw is countersunk directly into the plastic.  How
strong would that screw have to make sure it pulls out of the plastic before
it breaks?  Almost anything would work.  Sheet-metal screws with Tinnerman
nuts in an airplane?  Lots of them in my Cessna and none of them have come
loose yet.  Trick is really to know when the low-dollar approach can work
and when to use the good stuff.  That's why I use all aircraft fasteners -
cheaper to do that than to carefully evaluate each application.  For
example, a typical access panel would be much better off, in my opinion, to
be held in place with clip-on Tinnerman nuts and sheet-metal screws than the
anchor nuts and machine screws.  Problem is you have to put a recess in the
flange for the nut so it is easier to use the anchor nut even though it is a
lot more work to install and to replace if it wears out, which it will.  To
use a 12-volt automotive relay wouldn't give me pause at all.

Gary Casey
ES project