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Engine basics => Engine set up tips => Topic started by: Larry Wong on June 21, 2006, 07:37:44 PM
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Today I was flying with a friend and His new Cavalier had a P/A 40 each time we launch his plane It would run away, He had a Boli 11x4 3bld I launch it at the same RPM that I do on Mine . after 3-4 tray I changed his Prop to Mine and set RPM what I do to mine and it had a good 4-2-4 the prop I use is a Bill Lee 11x4 3 bld can just a prop be that diffrent or is there something else that we are missing? <=
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Larry
what does run away mean? are you saying it goes into a fast 2 cycle?
or does it go too fast in level flight ?
or does it go too fast in manouvers?
if so did you try to set the needle richer?
the combo of the Bolly 11 x 4 n 3 blade and PA 40 is working on ships all over the country.
Give me a little more detailed info.
there is very little differance between those 2 props, so it doesn;t make sense that he would have that huge of a change
regards
Randy
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Randy It just will not take a needle, eather to fast or to slow, that what 's so puzzleing, as Both of mine runs great . I'm thinking that it might not have enough time on it yet. but when I change his prop to mine it works, take of one lap then 4cyc, but with his bolli were ever it's set it stays on the ground but when it unloads it flys fast, when richen it up it flys to slow!
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HI Laryy
You wrote me a while back as to how well the motor and 11 x 4 Bolly worked on your plane.
If the same setup isn't working on his its time to check things out.
You say it won't hold a setting, if this is so the fuel system needs to be checked to find out why the RPMs on the ground will not be steady. or the in flight RPMs are not steady.
If the plane goes rich or goes lean when you launch it, the same applies. Try to get the tank as close as you can to the motor and have a very secure mount.
If this is just simply that it goes too fast in flight, you need to change the pitch of the prop, or drop to a lower % nitro, or add a head shim.
What lap time are you getting and what lenght lines are you flying on?
Regards
Randy
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I'd check the prop balance. Could be vibration induced fuel foaming, especially on a profile. If that's not it, then check the prop pitch. Make sure the LE of the blades is correct; pretty sharp, definitely not "safe"/blunt. Lots of performance in props...gained or lost. Details! ~ Steve
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Larry,
Might be interesting to see how his prop performs on your plane???
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Randy Powell has a PA .40 "Merlin" in his Cobra...it did some similar stuff at Stunt-at-Thun, like 4.2 sec. laps. Turned out that the engine mounting bolts were loose. That fixed, all returned to "normal". n~ Steve
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Thanks Guys Just got back from flying and it was a leak in the tank, now that it was fixed , It fly's sweet as it can be . 65' lines at 5.3 laps and launch RPM at
10K with a nice 4-2-4 break ... j1
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What Steve says it true. I had a couple of runs on the plane that were head scratchers. Would be fine on the ground then go lean in the air. Not overlean, but well into the 2 stroke. Turned out I had an engine mount problem. Got that fixed and it was fine again.