Engine Tuning guide

[R-4-L]

lesson learned , and a hard one it was! Tuning an engine is probably the most important skill any nitro pilot would really need to master..

we see OS.91 (and its derivitives or mods) and YS.91 engines that perform in an amazing way that people start saying "must be some special ingredient in there"

Now, when someone buys his first 90 machine naturally would have certain expectations from his new machine, like me, I assembled my R90 with total concentration put into every step of building.. installed the engine (modded with OMI too). setup on rich to break it in.

then after 2-3 tanks, I got the urge to close down the needle, ending up over leaning the engine and I know that my engine even if fully broke-in, would never reach its max potential and horse-power I'd expect.

I think people like me who just went into the 90 world and have limited support in the field really need some sort of guide on tunning and breaking-in new engines and some sort of maintenance knowledge..

is there such guide flying around on the web? (I visited Eric Larson's tuning page and it was very usefull but i felt that its not enough)..

everyone has his own theory on how to tune an engine and how to find out whether your engine is too lean or too rich.or when to know that your engine is infact broke-in well. some inputs ofcourse would be greatly appreciated not only by me, but to the 100s of heli pilots who are puzzled and are kinda shy to ask! i'll admit my lack of skills and knowledge on this matter and the net shall lighten me...... (in a good way hopefully)

Regards,

[R-4-L]

http://www.littlerotors.com/article...40103/index.asp

got some replies from RR,,


Cheers Mates!

[TerryBelanger]

Link is Dead

[kjkelly]

http://www.littlerotors.com/articles/enginetuning-140103/index.asp

[steve9534]

You might take a look at what I wrote under the title "Needle setting". It's a start, not the end of the matter, but may help to get you in the ball park. As for using the back plate temp as a tuning gauge: the temp can change significantly in the time it takes to get from flying, even hovering, till you get it set down and get a chance to check it. I know that Curtis has popularized this technique, but I would use it cautiously for the reason given. I've seen repeatedly folks who have the low end set too rich from the factory and try to compensate by adjusting the high end needle. This gets the mid range mixture correct for hovering, but is really too lean once the carb is fully open and you're flying around. The motor is hot/lean flying but has chance to cool down as you come down to land and the carb is on the (rich) low end circuit. The back plate temp under these circumstances doesn't tell you much about the temp when flying. The other common comment I hear is that the motor is producing lots of smoke so it can't be lean. If you're using the usual CP30, Magnum, or new Wildcat CY fuel blends, they have so much oil that the motor will still produce a lot of smoke even when seriously lean. Again this marker of engine tuning I believe to be seriously flawed. You might try my method, it's worked for me. I have some motors that are 10+ years and still run well w/o anything other than some careful needle setting. One YS61 is still on it's original bearings after 17 years. Hope this helps. steve.

[ChrisLaFollette]

I use the backplate method and I fly somewhat low so when im ready to check it the motor doesnt have long to cool down. I also listen very carefully to my engine from idle to wide open. I use sound and backplate temp to tune my engine. I can spot a lean engine in an instant. You just have to experience it first hand to really learn or get better. When I was learning I would listen to a freinds motor who knew how to tune and id tell him how much to richen it/lean it and what needles and he told me right or wrong. Usually I was right though. It seems like a BIG deal and it is but not as big as people think. Just dont be afraid to mess with the needles. :lol: You'll get better the more you fly. Just never run it when you hear that sizzling crackey sound coming from the engine. Thats the lean sound. Just ask HC or Clint or Eric next time you see them at a funfly to help you out. Im sure they could teach you more in 5 minutes than I could in an hour.

[Shortman]

I think the lesson I learned from tuning glow engines and gassers the past 5 or so years is 1) Patience, and 2) Your going to have to do it sometime, no matter how much you read on tuning, every motor is a little different.

:cool: