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Engine basics => Engine set up tips => Topic started by: bob whitney on January 26, 2016, 11:32:24 AM
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OK have a T/L 60 powered Big Job. lap times at 4.8 to 5 sec RPM 8,600 Prop wide blade 123/8 x 6 carbon .
the motor is at a dead 4 stroke .i would like to increase the RPM a bit so that it will run a little cleaner and keep the same lap times . what are my choices, Oh, fuel is 10%
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OK have a T/L 60 powered Big Job. lap times at 4.8 to 5 sec RPM 8,600 Prop wide blade 123/8 x 6 carbon .
the motor is at a dead 4 stroke .i would like to increase the RPM a bit so that it will run a little cleaner and keep the same lap times . what are my choices, Oh, fuel is 10%
Depitch it to 5.5", then see.
Brett
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You didn't mention line length. Get the engine happy then lengthen the lines if possible. I always start with lines a little long. It's easy to shorten them and they haven't invented a line stretcher yet!
Type at you later,
Dan McEntee
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lines are 62 ft eyelet to eyelet. will de pitch to 5.5 and see what happens
would that be better than shortening the prop
it fly's great as it is, plenty of pull, just sounds like it will quit at any minate
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5 second laps is too fast. You want at least 5.2 seconds, or as slow as you can push it.
Note that when you slow it down not only will your trim change, but trim problems that had been masked by excessive speed (and centrifugal force) may become bothersome. I would expect to lower the speed, then spend time dinking with the trim, then lower the speed, etc.
I think I'd try it on the longest possible lines before I started lowering the speed -- but then, I seem to have a preference for running the airplane fast and keeping the lap time up with long lines.
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First thing you should do is drop the nitro to 5%, this time of year power is no issue, or should not be with a ST 60 on a BigJob, that prop is small for a ST 60, so don't cut the diameter down, most people using my 60s run a 13 inch 2 or 3 blade, That will help clean up the run
Next is to make sure you have a good..hot.. plug... A Glow Devil 300, T-Bolt RC long , and similar p;lugs run well in the ST 60. The 60 will cycle very cleanly if setup properly
You never mentioned the Venturie or restrictor size, that is also a great trimming tool.
But just dropping the nitro, to get the same run you will need to lean the needle, that may do it without any other changes
If not I would consider going to 63 ft lines eyelet to eyelet , You have just a small problem, it won't take much to get it trimmed as you want
I setup over 600 of the ST 60s for people, and this all worked well for them, as the weather gets warmer you can bump-up the nitro...if you need it.
Randy
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Randy, i like the 5 % idea, will try that first .then de pitch a prop