Lower idle speed
#1
Thread Starter
Lower idle speed
i have a saito 150 what prop would giv me a lower idling speed, i remember the last time i used this engine i had hard time achieving a low reliable idle speed.... which prop size would get me closer 16x8 zinger pro or a 15x 10 apc
id like to confirm what i was told at the field with RCU as i trust my fellow modelers here as well
id like to confirm what i was told at the field with RCU as i trust my fellow modelers here as well
#5
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Join Date: Jan 2006
Location: New Milford,
CT
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RE: Lower idle speed
I'm curious as to how low an idle you want. With the low speed set correctly, that engine should easily idle around 2000 rpm. I have a Cline regulator on my 180 and it definitely helped in the idle department. I've had it idling as low as 1350 rpm with no glow heat. I wouldn't trust it that low, though. It will idle all day at 1800 rpm with the MA Classic 18x6.
#6
Thread Starter
RE: Lower idle speed
i dont have a tach yet, but i want it as low as possible yet reliable.... the reason im concerned about this is because last time i used the 150 the lowest reliable idle was too high, i had to really force the plane down, also someone had to keep hold if it on the ground on the lowest idle it would want to roll fast.... thankfully i joined a a club a couple of months ago that has some 4 stroke buffs im sure its just a matter of adjusting it correctly....
this is what it was doing last time i used it.... i would get the idle to about where wanted it, then the engine would start popping and it was really shaking the fuse
thanks
this is what it was doing last time i used it.... i would get the idle to about where wanted it, then the engine would start popping and it was really shaking the fuse
thanks
#8
Senior Member
My Feedback: (14)
RE: Lower idle speed
Real high pitch pattern props are going to pull your model around on the ground at idle. They will also make it difficult to land your model with the engine running. Friends of mine used to have to kill their pattern ship's engine on approach, in order to get the model down on our small field with any predictability, due to the huge pitch they were running in their props.
Ed Cregger
Ed Cregger
#10
Thread Starter
RE: Lower idle speed
ORIGINAL: blw
The low speed needle valve is set too rich.
The low speed needle valve is set too rich.
#11
Senior Member
RE: Lower idle speed
ORIGINAL: MetallicaJunkie
I have a feeling it is..... i have it set flush like the directions say.. ill give it a try tonight when i get home
ORIGINAL: blw
The low speed needle valve is set too rich.
The low speed needle valve is set too rich.
#13
Senior Member
RE: Lower idle speed
ORIGINAL: MetallicaJunkie
I have a feeling it is..... i have it set flush like the directions say.. ill give it a try tonight when i get home
ORIGINAL: blw
The low speed needle valve is set too rich.
The low speed needle valve is set too rich.
Adjust the high end for maximum RPM less about 400 rpm to the rich side depending on the conditioning of the engine. Fully broken in you can get away with 300 rpm rich but with a new engine, I would go around 600 rpms rich.
Then you adjsut the idle . Set the throttle as slow as the engine will run without stalling and then at this throttle setting lean the idle to achieve maximum RPM.
Go back and adjsut the high end again.
Go back and adjust the idle again. This thime the idle should be much slower.
The work on the transistion.
Run the engine up after it is warmed up and hold it at full throttel for a few seconds to clear out any loading. Go to full idle and let it run there for a count of 20 to 30, the punch it full throttle. It should jump to the throttle. If it dies as soon as you punch it, the idle is set to lean, open it up 1/16 turn at a time until it jumps to life. If it stumbles and snort before increasing RPM, it is to rich and again adjust, this time to the lean side, 1/16 turn at a time until it jumps.
Go back over the whole sequence one more time and then don't screw with the jets unless there is a big change in temp, humidity, or a new fuel mix.
You just have to have a tach to do this. Once you have adjusted an individual engine a number of times, you will be able to hear that engines and determine what needs to be done. Untill you get to know the engine though a tach is necessary. As soon as a tweek at the field doesn't work like you thought it should, start from step one, otherwise you are going to meander further and further from the proper setup.
The previous suggestion of a 2000 rpm idle is a good target. A couple of our guys with big birds use an air brake setup to slow down the plane after landing. You might look into setting up someting like this on your transmitter after you get the idle taimed.
Don
#14
Thread Starter
RE: Lower idle speed
thanks for te indepth reply, i went flying today the idle was great but i couldnt get the engine to run great on the high end, im going to"reset" the engine to factory settings and print your post and tweak it here at home befor i go out tot he field again on saturday.... another reason i suspect the the high end lacked wass because i was trying to get rid of a batch fai and some 10% i mixed together..... ill use some fresh 15% next time
#15
Senior Member
My Feedback: (3)
RE: Lower idle speed
ORIGINAL: MetallicaJunkie
i dont have a tach yet, but i want it as low as possible yet reliable.... the reason im concerned about this is because last time i used the 150 the lowest reliable idle was too high, i had to really force the plane down, also someone had to keep hold if it on the ground on the lowest idle it would want to roll fast.... thankfully i joined a a club a couple of months ago that has some 4 stroke buffs im sure its just a matter of adjusting it correctly....
this is what it was doing last time i used it.... i would get the idle to about where wanted it, then the engine would start popping and it was really shaking the fuse
thanks
i dont have a tach yet, but i want it as low as possible yet reliable.... the reason im concerned about this is because last time i used the 150 the lowest reliable idle was too high, i had to really force the plane down, also someone had to keep hold if it on the ground on the lowest idle it would want to roll fast.... thankfully i joined a a club a couple of months ago that has some 4 stroke buffs im sure its just a matter of adjusting it correctly....
this is what it was doing last time i used it.... i would get the idle to about where wanted it, then the engine would start popping and it was really shaking the fuse
thanks
#16
Senior Member
RE: Lower idle speed
ORIGINAL: Cyclic Hardover
I can relate to this now. I have a 40 size P-51 withga Saito 100. Trying to prop it right for speed but at the same time, it was to roll around pretty fast even when its nearly shut off.
ORIGINAL: MetallicaJunkie
i dont have a tach yet, but i want it as low as possible yet reliable.... the reason im concerned about this is because last time i used the 150 the lowest reliable idle was too high, i had to really force the plane down, also someone had to keep hold if it on the ground on the lowest idle it would want to roll fast.... thankfully i joined a a club a couple of months ago that has some 4 stroke buffs im sure its just a matter of adjusting it correctly....
this is what it was doing last time i used it.... i would get the idle to about where wanted it, then the engine would start popping and it was really shaking the fuse
thanks
i dont have a tach yet, but i want it as low as possible yet reliable.... the reason im concerned about this is because last time i used the 150 the lowest reliable idle was too high, i had to really force the plane down, also someone had to keep hold if it on the ground on the lowest idle it would want to roll fast.... thankfully i joined a a club a couple of months ago that has some 4 stroke buffs im sure its just a matter of adjusting it correctly....
this is what it was doing last time i used it.... i would get the idle to about where wanted it, then the engine would start popping and it was really shaking the fuse
thanks
If you're confident in your piloting skills you could cut off the engine during final. I've done this, but personally don't like the extra risk involved.