…I have the
standard Lancair 320 air box. At high airspeeds such as 200 mph or more,
my carb heat will come out about 1/2 inch and the engine of course runs a
little rougher. I push it in, it comes back out all by
itself. So my fingers get tired holding it in…
Matt,
I had exactly the same problem with
the oil cooler door on my Lancair IV-P. The door would “blow” shut
at airspeeds above about 160, causing an oil over-heat. I need to note also,
that Lancair’s Tim Wilson advised me that I would have this problem when
he inspected my airplane. He told me that I should have used the
Lancair-provided locking push cable for this. (I chose to use a standard push
cable as I had several, and wanted them to all look alike on the panel—Don’t
say it!)
In any case, both ACS and
Lancair have a very nice push cable with a spring-loaded “push to unlock”
button in the center of the operating knob. Works like some RPM control cables,
but much smaller—it has a black knob, and is just a bit larger than the
standard push cable.
I changed out the offending cable
in my IV-P, and have had no trouble since. I might add that the pressure on
this cable while in flight is significant. Now that it’s worn a bit and
loosened up, it will push to the closed position at any time the button is
depressed to unlock it.
Give this a try; it’s designed to work your specific problem.
Bob Pastusek