At 05:36 PM 7/12/2010 Monday, Tom Buese wrote:
>Since my 84 flaps still work really well, I will treat them w/ the
>respect that they still deserve.
>Sometimes earlier is better?

I don't know of any P/M that would be useful for them.  They're right
in the incoming air stream with any grit that it carries, and they
work on the balance between ram airflow and blower output -- when
open they let ram air bypass the blower and by doing so short-circuit
the blower output back to the input.  Total swing is maybe twenty
degrees and they weigh a few grams.

Best thing for them is don't drive where it's gritty, I
reckon.  Oiling the pins might help them or it might just trap grit
so they wear faster.  Graphite powder might be good.  Can't get there
without splitting the box, though, I don't think.  I'll be opening my
heater box this summer so I'll have a better memory of how they're
situated.  Maybe some photos as well.

A possible replacement might involve thin polyester(?) flaps that
curl open under ram air and flex back when the pressure
equalizes.  Or of course electronic sensors and electrical actuators
for something much sturdier, for the experimental-physics crowd. ;-)

Yours,
David