Jeff,
I hope the fix you describe will solve the cooling issue.
When I did the firewall-forward work, Andy Draper (at that time eith EA2004)
recommended that I closed the lower NACA - it should never have been there
for the 912/912S installations, he said, only for the 914's turbo. As I
recall our conversation, his point was that all this additional air coming
in at a place where it does not do any good for 912/912S, competes with the
cooling air coming in through the cowl front openings in getting out again.
In other words, the more places you let air in, the less air actually comes
in through each inlet when the outlet area is not increased. The NACA
therefore effectively reduces the air flow through the cowl front, which is
the air flow intended to cool the cylinders.
Your fix should therefore improve things, I believe.
>From what I can read between the lines, you don't have the Rotax glassfibre
cooling shroud over the cylinders and its (third) opening in the cowl front?
As air in = air out, I trust you have already ensured that you have maximum
possible outlet area aft/below, without reducing the air flow through the
coolers?
Regards,
Svein
LN-SKJ
Jeff wrote:
> On my cooling issues it's just a mater of too high of pressure in the
> lower cowl not letting the upper air from the top intakes down through.
> Until now the lower NACA was just shooting air into the lower cowl with no
> direction causing the this high pressure. John Hurst told me some time ago
> the demonstrator was set up this way and it was fine. This overheating
> never showed until this hot Tennessee heat wave hit. Again I believe I'll
> have it solved. I have glassed in the lower NACA to receive a 2 inch scat
> tube. This I will run to the upper part of the cowl. I hope it eliminates
> the high, lower cowl pressure and increases the top air pressure to force
> more air cooling down through the cylinders. I should have it all fixed
> in time for next weekend's fly-in at Rough River.
|