My shroud is fed by
a 2" dia scatt hose that route air from a small NACA scope (about the same size
as on the side of an RV aircraft) the duct opening is under the cowl about 2/3
of the way back from the front. I concluded that during high power climb
would be when I would need the cooling air the worst. Seems to work for
me. Interesting, I have had two power out events - but, neither due to
fuel/vapor lock {:>). INterestingly, its not high power that is
generally the problem. At high power, you generally do not recirculate
much fuel, much more of it is being consumed and replaced with new fresh cool
fuel. Its after you throttle back after a hard climb and stay a lower
airspeeds like in the pattern, then much more fuel is recirculated back to the
headertank (and bringing with it the heat build up).
Thanks
Ed;
I'll order one of Van's pre-made NACA ducts tonight as this
will eliminate downtime for fibreglass work, and tomorrow I'll phone a few rad
shops.
Do you usually run with both FI pumps on while
climbing? As I didn't have this problem to this extent previously,
it reaffirms your theory that most fuel is consumed at full power with less
being recirculated when a single pump is used, but with both pumps running, I
still had allot of fuel being recirculated, while picking up full power
heat.
It seems that running with both pumps on for extra safety
may in fact, have contributed to the problem? Just another
theory.
S. Todd Bartrim
Turbo 13B RV-9Endurance
C-FSTB
http://www3.telus.net/haywire/RV-9/C-FSTB.htm
"Whatever you vividly imagine, Ardently desire, Sincerely believe in,
Enthusiastically act upon, Must inevitably come to
pass".
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