REFLECTOR:MORE ON COMBUSTION AIR AND COOLING

[Jim Agnew]

If you notice I take my intake (combustion) air from the
underside of the wing just aft of the spar which is a high
pressure area or you are not flying.  I have flown both
with and without a small scoop and it doesn't seem to make
any difference.  Given the high pressure and a giant air
pump on the other end with a 4"x10" filter face pressure
drop isn't much of a problem.  It appears that MP may go up
slightly at rotation so I may be getting a little extra
boost in ground effect.  

I know that Alan Shaw found high air flow with wing mounted
oil coolers with the air coming in the bottom of the wing
and out the top.

Jim
--- RJohn15183@aol.com wrote:
> In a message dated 9/16/2003 11:04:31 AM Eastern Daylight
> Time, scott@tnstaafl.net writes:
> 
> > Both planes I have flown with a ram scoop, Mooney and 
> > Velocity, showed about 3/4" of MP increase at apx 150
> knots.
> 
> Yes, I thought Jim had made a very good point a few
> e-mails back that where I was originally drawing intake
> air from before I built the scoop must have been in
> negative pressure air. 
> 
> Since everyone seems to agree that 3/4 of an inch is
> about right for a ram air scoop that must mean I was
> loosing about  1.25 inches by drawing from where I was,
> under the engine with no scoop. 
> 
> So lesson learned: Think about where you put that engine
> intake! It can cost you significant power. 
> 
> DM Rob
> 
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=====
James F. Agnew
Jim_Agnew_2@Yahoo.Com
Tampa, FL
Velocity 173 Elite Aircraft Completed & Flying