I learned a valuable lesson, just recently, like, within past 2 days, and I would like to share this with you.
It deals with gassers and tuning.
I have friends, who tell me: "I have never touched my needles" since installing a brand new motor. And I guess, i figured, this was something to be proud of. "My engine runs great, and I have never had to mess with the needles".
I guess that sounds nice. Not bragging. Not arrogant. More of a matter of fact statement demonstrating that one person's good fortune.
I have heard this for years!
3 years ago, I purchased my 1st quad engine. And not only this concept of "don't touch the needles" was on my mind, but also, the fear of attempting to tune both carbs, and the chance of a dead stick, really scared the bejeebees out of me.
SO, for over 300 flights, I never did such thing, seemed to me, that it ran great. This was an airplane, with canisters (KS 95) and 2 into 1 headers.
I did notice, over the years, kind of like in the back of mind, almost sub conscious: "my airplane sure does seem lethargic...."
OK, be back to that soon....
then, 1.5 years ago, I got me a second quad motor, for another Yak. And, I did the same. Never messed with the needles and never "tuned" it, for fear of a dead stick. this was sort of a back up airplane, and a good friend, earlier this year, was able to fly this airplane in the unlimited class at a contest, and he made the comment : "looks like it is running out of steam on an upline, with two elements, one of which is a snap".
And I noticed this, and again, something in the back of my noggin, subconsciously, made a mental note of this. A tiny light bulb turned on, but not enough to make me do something about this.
be back to this soon....
then, this year, I built a third 40% for the fleet, another extra, and I put in a 3rd quad, this one, again, with the KS 95 cans and 2 into 1 headers.
and for some reason, I said, let me tune this baby. from Day 1, i tuned this puppy. Spent a good amount of time, with my friend, doing this, and then flew her, and WOW!! Is all i can say. I knew, now, there is a definite problem.
Imagine, all 3 airplane have same exact brand motor, same exact brand and size propeller, same exact exhaust system.
and using my onboard telemetry, i was able to compare the three of them, their peak rpm doing flight.
and an outstanding difference, between the 1st two, and the last one (which was tuned from day one).
here are my results:
if you do not tune your motor, when using canisters or tuned pipes, and run her rich, you will end up clogging the muffler system over time, also depends on what brand exhaust it is, but for the ones I used, I guess, they are sensitive to this. and the more rich it is, the sooner it will get there, that is, to less performance.
the 1st one, with over 350 flights now, I removed the KS canisters, and went with JTEC mufflers, and the increased performance is phenomenal. I am getting peak rpm, in the air now, of over 7100 rpm, turning a 30 x 13 EVO Mejzlik 2 blade prop.
the 2nd one, last night I did this, I spent over 5 hours, trying to tune it. came up with conclusion canisters were clogged, *with only 50 flights on her*, and removed the KS, and installed, semi new Pro Flows, and on the ground, gained over 300 rpm, again, same exact prop. I need to fly her and report back on the peak rpm in flight.
the 3rd one, peak rpm , in the air, was over 7300 rpm.
Well, I no longer have that airplane, since a tree grabbed it from the skies, but, the motor is currently at its birth place, getting looked at, and when it returns, its new home will be a Carden Pro.
SO, my message to you all, always tune your motor, from day one. DOn't think, "I never touched my needles" is a good thing. In fact, if you or anyone else ever says that, I will assume you are not getting top performance.
And if you want to learn how to really tune your motor well, which I did from this one gentleman, look at the thread by Terry, from Terry's Customs.
You all have a great day.
