[phileo]

Hi guys.
I have a .46 tt that refuses to work properly.......it seems to not want to get leaned out and when I put it upwards (plane) it seems to lean then lose rpm. I have fiddled with the thing and I have a new glow plug in it...turned the low end in to zero then out 2.25 turns. Needle is out about 2.5 turns. What could be the cause of this? I have it running very rich to stay at a constant rpm. This is not cool as I am using a whole lotta fuel to fly for about 7mins
Any help would be greatly appreciated.

[bbbair]

Phil;
First a bit more information please;
Is this a new engine, or a used one that you just picked up? Any damage etc.

If it's new, how much fuel has been run through it? Has it been broken in properly or cooked by a rookie?

What prop is on it and the type of fuel?

Now - are all of the seals in good order and in place? Or are they dried out and cracked? Is the engine properly secured to the engine mount or is it loose and vibrating?

A little more detail and you can get a lot more information!

[Gary Maker]

It would be helpful to know the age of the engine but here is a couple of suggestions assuming the engine is in reasonably good condition.

I just checked the low end needle on my TT46 Pro and it is out from the bottom 1 1/2 turns. Your setting is a good starting point for the following!

First of all, and do this very very carefully, get the engine started and running somewhat relyably. use a long thin screwdriver and while the engine is running, turn the low end needle in slowly. You will hear the engine start to pick up rpm as it comes to the best setting. Keep turning it slowly until it peaks at the best rpm. Usually you will go just a tad too far determining this so back it out slightly and it should be set.

Now readjust the top end for max rpm at high speed and back off about 1/4 turn or about 200 rpm below peek!

If your uncomfortable doing the low end adjustments with the engine running, then turn it in 1/8 of a turn at a time with the engine off and start your engine to check for a good relyable idle and smooth transition to top end! Keep stopping the engine and turning in 1/8 turn until you get good results!

Also make sure your carb is in the crankcase hole good and tight against the "O" ring. Air leaking here could cause problems. Double check all your fuel lines and tank pressure as well.

Are you using fresh fuel? And even a small speck of dirt in the carb inlet or needle could cause bad running. Check everything as thouroughly as possible.

Good luck and please let us know if you solve the problem!

[phileo]

Thanks for the info guys!
The engine is used and was purchased from Rdemy and he had about a gallon run through it...he ran richer to preserve engine life as well.
I will try to adjust the engine while running....I have long screwdriver that will keep me clear of the prop! I think that you will ge tthe most accurate adjustment while running.
Gary......sorry my friend for not getting the crystal back to you promptly as we moved and purchased a century + home and are renovating as well as the fact that some of my rc stuff is packed away and the crystal is in with that stuff!
As soon as I get at it which should be this week I will have it in the mail.
Happy landings fellows.
Ps....if your plane rolls to the right with full deflection on elevator.....what is happening? It only happens when you pull all the way back on the stick.....plane is a comet pattern plane. Could it be torque? or if it was torque, wouldn't it be veering to the right all the time? The plane flies perfectly straight and is super responsive. Could I have too much elevation happening that it makes it unstable? CG is perfect btw.

[bbbair]

Yes you have too much elevator deflection, it's called a snap roll.
Decrease the amount of elevator and try again.

[cplant]

A couple of other things to check as well on the rolling thing. If it's a split elevator make sure that the ellevator halves are even with each other through the full range of deflection. Also check that the plane is laterally balanced (right to left). If one wing is heavier it will have a tendency to roll that direction when the wing begins to stall (ie. too much elevator). I know it sounds kinda dumb but make sure if you have a computer radio that you haven't inadvertantly activated a mix. I was about to test fly someone's Twist last week and as I was checking things over noticed that when I moved the ailerons left the elevator went up and when I went right it went down. They had accidententally set an aileron to elevator mix (and it was set to "always on"). Would have made trimming the plane lots of fun.

Most likely it is a combination of things. Almost definately too much elevator throw. The fact that it always goes right says that something else isn't quite right though. It could be something I mentioned above or any number of less obvious things, like a slight twist in the plane or one of it's flying surfaces. Weight as always is a factor too. A heavier plane (particularly with taperec wings like a pattern plane's) will exhibit the up elevator - snap roll tendency sooner than a lighter plane.

Torque would make it go left with application of power. If it did the right roll when powered down I would maybe say that torque is a factor (plane trimmed right to compenstate for torque and becoming noticable when power is reduced). The fact that it goes right (I'm assuming as you pull elevator you are also powering up to go vertical) would make me guess that it has nothing to do with torque as the it would actually have the opposite effect in this situation.

[phileo]

Thanks for the info guys.......will try all of the above!
See ya around.