In a message dated 17/06/99 12:28:29 Greenwich Standard Time,
Roger.Mills@btinternet.com writes:
<< Has anyone found a neat way to increase the ventillation behind the panel?
>>
Apart from crew comfort, I found it absolutely essential to get the
instrument bay temperature down to allow a 10.4 " TFT screen to survive. This
will not take more than 25 C.and having parked a max/min thermometer behind
the instruments I was regularly finding 40 to 50 C. As it is mostly coming
through the firewall (the rest from exhaust gases heating the bottom of the
pilot side footwell), anything cooling the engine bay will contribute, and
if you have no cold box, it should help the carb air too.
A dramatic drop resulted from a adding slotted vents in the top of the
cowling.
Then although we are supposed to have removed all lagging from the exhaust
pipes, I have only removed the first 9" or so. This was done some 50 hrs.
ago and inspection of the lagged continuation shows no signs of flaking or
pitting. The lagging is sprayed with the high temperature reflective Al.
paint available for the purpose, though there is the consideration of
changing the sound velocity and tuning. I doubt if the Rotax is that fussy.
Allowing the air behind your panel to circulate out into the cabin will
clearly help. Large holes in the bottom (and mebbe the top) of the
instrument module where there is no structural implication will do this. I
already had one to connect up the firewall plugs. The screen also needed
tilting out of the plane of the instruments for optimum contrast viewing, and
this provided unobtrusive air slots top and bottom. This could be applied to
any shock-mounted (6 instrument) panel you might install.
Finally slots from the outside world just below the windscreen work wonders,
so much so that you need in-flight closures, preferably more sophisticated
than stuffing in a handkerchief. These are not so easy to make water-proof
though I have seen some neat flush stainless-steel flaps worked by cables.
Mine are just plastic, and I carry a light tarpaulin with rubber straps to
cover the whole cabin for parking outside.
Graham C G-EMIN
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