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Congratulations, Brian on a successful first
flight.
The most frequent (but not sole) cause of low power
is air flow and/or low air/fuel ratio. Its fairly easy to add more fuel
(mixture knob), but not as easy to get more air into the engine.
Easy way to tell the effect of your filter is manifold
pressure. See what it is at WOT with and without filter. If not more
than 1/2" Hg pressure difference then the filter is not having much
effect. If the filter is having an overly adverse effect then manifold
pressure should be less (and rpm also).
As Tracy pointed out (at least for us early guys) it generally
took us a while to get it all sorted out, but you'll get there.
Ed
Sent: Saturday, September 11, 2010 10:51 PM
Subject: [FlyRotary] First flight
RV-4 #2366, tail # N52BT made it's first flight today. It didn't make
enough power , so only one lap of the traffic pattern was made before the pilot
landed it. From a standpoint of flying qualities, it was just like any other
RV-4s- no out of trim conditions or other bad habits. No note was made of MP at
WOT, either on the ground or in the air, that's first on the agenda tomorrow.
But-- I only revved up to 4800 rpm on the downwind, so the flight was
terminated. I have gotten 5500 on the ground with the cowl removed, which means
the air cleaner was not in use. I am using a Fram paper filter, 6 inches by 14
inches. I think I am getting a big restriction from it, so I will remove it and
try some ground runs. I also think I'm running way too rich, about 34- 7/8s up
the scale on my EM2.
The good news is that neither the oil or coolant temps got over 160 the
whole time, and the plane was waiting on the ground for around 15
minutes due to traffic in the pattern prior to the flight.
So, I'm happy about the flight, but now must find out why I'm not making
more umph.
Brian Trubee
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