stunthanger.com
Engine basics => Engine set up tips => Topic started by: Tim Wescott on September 09, 2010, 03:10:37 PM
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Plane: Sig Skyray
Tank: An old Perfect brand wedge tank, 2oz. Before that was a 4oz DuBro clunk, with about the same list of symptoms.
Engine: OS FP, with the remote needle valve.
I'm mostly pleased with this plane that I bought off my nephew, but I'm not exactly getting rock solid engine runs. Today really put things in the spotlight because I forgot to bring my regular fuel and borrowed some with 5% more nitro. This required a different needle valve setting, which messed up both of the flights I got in.
Sometimes I get a nice engine run, sometimes it seems to richen up in the air, sometimes it leans out, sometimes the first half of the flight is nice, sometimes the last half. And any time something changes (like fuel) I have to start the whole struggle over.
Argh.
Suggestions? Is this just because of the remote needle valve, or are there other things I should look at before I blame that?
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What size FP are we talking about? My guess it's a 20 FP or 25FP I have a FP 20 on a Skyray and it's as stock as you can get. it works great on a APC 9x4 with stock muffler. As per Brett Buck recommends.
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Oh, right -- displacement.
OS FP 20, running a 9-4. You're running a 9-7?!?
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Woops ment 9x4 APC 10.% Powermaster fuel and pressure feed,soft 2cycle
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Woops ment 9x4 APC 10.% Powermaster fuel and pressure feed,soft 2cycle
Hmm. That's pretty close to what I'm using. I've only got a dozen flights on it -- maybe I just need to keep at it.
But when the motor went soft in the inside loop and the outer wingtip 'shooshed' through the grass at the bottom -- that kinda got my attention.
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Oh I forgot to say that I also added 1" to the elevator, it makes the plane turn better but not faster, just more area. the horn stays the same so the plane is still stable, give that a try.