intelinside

Starting to really have a lot of fun with my trainer - can do all the basic aerobatics, loops, rolls, stall turns etc, even if they are not always pretty. Have increased the throws way above the recomended for the rudder and elevator - allows heaps better response. Loving it and can land closer and closer to where I desire.

As a consequence of the more agressive flying, I find myself using a lot higher revs on my TT .46 pro with a 10 x 6 prop. Sometimes I just hold it flat all flight until I land (Up to 10-13 mins).

Would this be overheating it? How do I tell? Should I be using a different prop? Should I make the mix a bit richer to compensate?

Also, the trainer has a typical one servo configeration for the ailerons and I cant get any increased throws out of them. The arms are hitting the hole in the wing. Any ideas on how to overcome this?

All ideas will be appreciated, Cheers.

tIANci

Just because you are using a 10x6 prop does not mean you are overheating the engine. It depends on how lean you are running the plane or how much you are overloading it. You need to feel how hot the engine is after flying ... for me I always check the engine temp when it lands, I will feel how hot it is. Usually I let the engine get hot enough for me to touch it for like a second or so only. Not burning hot like a hot plate but just hot. I used to be into cars so engine temp was an issue.

There is the water drop test. Use a drop of water and the engine should be hot enough for it to evaporate in like 3-4 seconds. These are only guidelines. A temp sensor would be great ... I find that running the TT46 with a 10.5 x 7 at 14,000 RPM is ok for me. The engine was not overheating ... i.e. loosing power.

intelinside

Silly question then, but how do I know if I am running it too lean? Is there an easy way to tell?

What is the best way to properly lean and tune my engine?

Sorry, only new to this game.....

tIANci

When you run too lean or using too lousy a fuel the engine will over heat. Best on tuning tips try this ... get your engine at a base setting. Usually for me its like 2.5-3 turns out on the high-speed needle and about 3-4 turns out on the idle needle (throttle barrel fully closed).

All of these settings are very rich. You'll have to start the engine at about 1/4 to 1/3 throttle. Once the engine starts (let it warm up a bit first), advance the throttle to full. You can then lean the high-speed needle until the engine is running just rich of peak RPM. It means you lean until the engine starts to loose RPMs then you rich it back about 1/4 turn.

Once you have the high-speed needle set, you can retard the throttle a bit and use the idle needle to adjust the engine. Retard a bit, and adjust. Keep doing this until you have reached the desired idle RPM and mixture. Remember, since we started out with an intentionally-rich setting, the idle mixture will have to be leaned. This means when you throttle up from idle the transition should be smooth. If it cuts then the idle needle is too lean, if it 'gurgles' then its too rich.

There are a few other ways, see if this works. A lot of people like to use the 'pinch' test.

p/s the question is not silly ... you are new and uninformed, we all were till we saw the light!!!

MinnFlyer

My Feedback: (4)

Just start your engine. Let it warm up for about 30 seconds, then pick the plane up and hold it level. Now bring the throttle to wide open, let the RPM come up to full, and then point the nose straight up and hold it there for about 5 seconds. If the RPM do not decrease, you're not too lean.

piper_chuck

My Feedback: (12)

In addition to what tIANci said, there's a common test to confirm it's not too lean. Once you get the high speed set slightly rich, hold the plane firmly with two hands and point the nose straight up, and keep it there for 5-10 seconds. If the engine speeds up when you first point it up, and does not begin to slow down, it's not too lean. This test also helps you confirm the engine will draw fuel through your manuvers.

britbrat

The 10-6 prop is a bit small for your TT.46 Pro -- particularly on a trainer. You would be better off with an 11-5 or 11-6, then you would get better acceleration & climb (maybe even unlimited vertical) without loosing level speed. There would also be no concerns at all about excessively high rpm's.

TPierce

Try an 11x6 apc prop. It may not be the problem but it will be a lot more fun. What % fuel are you running?

intelinside

Thanks for the advice. Have got a 11X6 prop, will put that on.

I am using 10% nitro fuel.

I think I have the high end needle adjustment fine, but what do you mean by the idle mix? Is that the screw in the carb barrel itself?

catboater

My Feedback: (51)

Get an APC 12.25 X 3.5 prop. You'll get much better performance for your basic aerobatics. It's the perfect prop for that engine on a trainer.
You may have to search for one as not all LHS's carry that size, but it's worth the time.

intelinside

Why is that better? Slower with more pulling power?

britbrat

Your trainer is never going to be a speed demon, regardless of the prop & the smaller diameter & steeper pitch props are literally wasting their efforts so you aren't getting the most out of your engine. I suspect that you don't have sufficient ground clearance for either a 12-4, or a 12.25-3.75 (the best prop choices for your plane for aerobatics), so an 11-5 is a good compromise, & an 11-6 will also work OK at the expense of some climb (vertical aerobatics).

catboater

My Feedback: (51)

Yes, that's it exactly. It'll require less runway to get airborne and it will slow down more for landing. Britbrat is right on saying your trainer will never be a speed demon. My son had a Sig Kadet senior and we had plenty of clearence but you may not. I'd check before I bought the prop.

tIANci

Cat ... you mean the 12.25 x 3.75 ... I have been using that on a lot of my planes. I like the torque ... love how the planes can just pull loops nicely. Landings are great with the wash that it creates.

catboater

My Feedback: (51)

Yes, that's what I meant, the 3.75. Great prop for .46-.61 size engines.

intelinside

Thanks, I'll give it a go.

ELTIGRE

one thing to watch for is loss of power/thrust after take off with engine screaming. almost sure sign your too lean-where upon you should throttle back to around 1/2 & land(most carbs richen at mid-range usually enough to save the motor )

Stick Jammer

Unless you intend to progress to pylon racing, that's a bad habit to get into. If you plan on getting into precision aerobatics you should be practicing good throttle management. Throttle down whenever the nose is down. Throttle up when the nose is up. If you are pulling high G's at full throttle on that trainer, I'm surprised the wing is holding up.