Help me get a better idle.

[2robinhood]

On on eof my gassers i would like to get a better idle.
I have perfect transition and screaming top end, but my idle.
Here is what is happening.
When I chop the throttle, idle is about 2050rpm and as it idles it will back down to 1850 after about 15-25 seconds.
I would like to chop the throttle and have it go to a consistant rpm.
Like on landing approch, when throttle is cut is seems to be at a high idle, as you gliding in, the throttle drops to where I would like it.
If I bring servo trim down after the 20-25 seconds the idle is way to low.
Am I lean? rich? am I stupid?

[rede2fly]

	Quote: Originally Posted by 2robinhood
	On on eof my gassers i would like to get a better idle. I have perfect transition and screaming top end, but my idle. Here is what is happening. When I chop the throttle, idle is about 2050rpm and as it idles it will back down to 1850 after about 15-25 seconds. I would like to chop the throttle and have it go to a consistant rpm. Like on landing approch, when throttle is cut is seems to be at a high idle, as you gliding in, the throttle drops to where I would like it. If I bring servo trim down after the 20-25 seconds the idle is way to low. Am I lean? rich? am I stupid?

no you are not stupid. but without seeing with my own 2 eyes its sounds to me like all the gas motors. and servos being used. how far away is the servo from the throttle arm?? on gas motors the throttle is very sinsative. so if the servo does not come to the end of its travel at the same spot each and every time, or the linkage has pressure on it. it will cause the throttle to allways be different which is allways seems to be the most noticeable is the idle. the motor at idle has to have the exact same spot each and every time or the idle suffers. this is where the better servos come into play instead of using standard or cheap servos. also the linkage needs to be the shortest that you can get. if i could place the throttle arm on the servo itself and not use a link i would it would be way more presise. my setups are as close as i can get and most of the time i dont have this anymore. what you are talking about. idle changing. quick way to see is bump the throttle then back to idle as fast as you can. note ide. then do it again but bring it back to idle slow as you can it should be the same if not. its either the servo or linkage

[planemain]

Very interesting.

Great info

[rcairflr]

Sounds to me like you are too rich on the low end needle. Try leaning it out a little at a time and see what happens.

[rede2fly]

here let me show you how i set up throttles. it works very well allways exact. allways the same fast or slow. pay close attention to the ball links, these are the very best. zero slop. i will never use the supplyed servo mount, they are never close enough and i refuse to use nyrods or long wire. they are not good enough for me. check it out. i can take a better pic

[Altavillan]

The engine has residual heat causing a faster idle, as well as a idle setting that will spin the prop faster until the load on the prop starts to slow the engine down. Two things I do, make approaches longer, and open the low to get more fuel in the engine. The richer mixture cools the engine faster than a lean idle setting will.

[2robinhood]

Thsi engine runs great.
High end is set with a tach to max rpm ( leaning till it starts to drop off ) and I backed it down only 100 rpm on top.
Low is set for a perfect transition ( no fourcycling sound through out rpm range ).
I pulled the plug and to my surprise it was on the blackish side.
The way it runs I was thinking it would be near perfect.
Could it be my oil mixture?
I run Penzsoil aircooled @ 40:1

Here is some videos.
1st one is a high end tach run, 2nd one is a high end tach ( different prop then the 1st video ) and some in flight.
By the way, in the second video, it would help if some numskull turned on the TX opto kill switch before he flipped it ten time.
I won't mention any names.

YouTube - CRRC GF26I with APC 17 X 6

YouTube - Laser 200 with CRRC GF26I

[Altavillan]

Pat Roy?

[2robinhood]

.

[2robinhood]

OK, went out flying.
Adjusted the low end leaner and got a better idle, still not perfect but it is better.
I did lose some top end rpm. It went from 9450 to 9250 rpm.
I know that low end adjustments will affect high end, so I riched and lean till I got top rpm on the high range.
The best that it would get is the 9250 rpm.
I did not set the low end back ( richer ) and see if the higher rpm came back.
Ended up with a thunder storm and 25-30 gust, maybe next time out.

[krayzc]

2k on a small gasser is pretty normal (25-30cc)