I am very new to RC-aircraft, and have just today baught my first trainer aircraft (a "Thunder Tiger CT 40") along with a TT GP 42 engine.

I am used to work with much larger 2 and 4 storke engines but I know very little about these tiny engines. I know that every engine should be run in properly before it is put to use and so I would be grateful to anyone who could let me know the following :-

1. Should I load the engine in any way during the break in process

2. What kind of cylinder head temperatures should I look for during break in .. I mean what is the maximum temperature that the cylinder head should reach without causing any problems to the engine


3. If I am to break in the engine on a test bench, would it be reccomended to do it in a normal vice, or would this cause distortion due to the temperature and if so, what sort of test bench should I construct for the engine


Thank you all for your help and time

I would follow the manufactures recommendation on break in.. I always do it with the engine on the plane. The process usually involves running it very rich to the point where it is 4 stroking for about three minutes, then idling, then running up again but leaner.. I usually run the motor for about 2 tanks worth like that before leaning it out to peak. even then I will back up just a click rich. Still.. it is best to do exactly what the booklet that came with your motor say's. good luck,

FW

jackall, you bought a great little engine. I started last October with the same (engine at least) and I've been very happy with it's performance and reliability. First regarding break in, follow the manufacturers directions, but get an electric starter. These ABN engines are very tight and mine took between 10-20 flips to start without an electric starter initially. Also when you're breaking it in on the ground alternate between 30-60 seconds of WOT, and 10-20 seconds of idle for 3-4 minutes at a time. Then shut down the engine and wait for it to cool down some (5-10 minutes), and repeat. Add more WOT time as you get more time on the engine.

I was able to run two 8oz tanks on the ground, and the engine ran well enough to go flying. You may need to play with the air bleed screw a little to get the engine to idle reliably. Remember that it works opposite of how your needle valve works though.

After you're done with the ground break in, check the tightness of all the screws/bolts on the engine. I've a bunch on mine vibrate loose. Definitely use thread-lock on the muffler bolts.

Never break in an engine in a vice...

Jack:
After break-in FW mentioned, before you put it in the air, change
to a new plug like the OS A-3. On a new engine you will get
residue of metal grunge that will cake the glow coil and cause low
performance and deadsticks. The A-3 cost more but is worth it.
Too many pilots can't figure out why their new engine keeps dying
after 2 or 3 min. in the air. If it is not too lean on the ground, then
it is usually the plug.

Randy

The ABC or ABN engines that do not have a piston ring should not be run in slobbering wet and rich! Without a ring to give a seal, they rely on the piston/liner fit and that has been designed to be correct at the normal operating temperature. When it is cold and the liner has shrunk a bit more than the piston, the piston is too tight in the tapered liner, which is why it is so tight across tdc when new. If you run it really rich, it stays cold and you have a high speed grinder. You need to get it up to near normal temp asap. Not fully leaned out but definitely 2 stroking. After a couple of runs the terrible mechanical tightness across tdc will disappear and all that is left is good compression.

Once I have got mine running, and giving enough thrust and proved that there is some semblance of throttle control, I get it airborne. Then fly it around at a variety of throttle settings. That gives it the proper cooling it is meant to have, the throttle up and down gets it hot and then allows it to cool off a little. It is the heating and cooling cycles that allow the liner and piston to adapt to their new shape (more heat on exhaust side means more expansion on that side).

Engines with a ring whether 2 or 4 stroke should still be run in very rich, though I do get them airborne as soon as they are developing enough thrust.

Harry

JACKALL,

Go to "search" and type in engine break in, This subject comes up consistantly (MARC, COULD WE DO A FORUM ON JUST THIS SUBJECT?) I do not believe in breaking in, in the air!! you have absolutely NO CONTROL! you need a smaller sized prop to keep the revs high (but not rediculous) and do not let the engine get hot. Somewhere here I posted DUB JETT's engine break in techniques.. Go to his web site and read read read..... And do all of your break-in test work on a test stand..... Have it broken in when you're ready to fly..

RON in NEVADA

Oh well, the instructions with my YS and many other engines to do the break-in in flight must be wrong!

Harry

HARRY MY RC FRIEND, You're "NOT" going to get a pis**** contest out of me..... if it works for you then there is no other way then yours. KEEP UP THE GOOD WORK! AND HAVE FUN !!

RON in NEVADA

I broke mine in in flight. Of course, that's also what the instructions say.

Actually Ron its not my way at all, its the manufacturer's way. I'm just obeying what Mr Yamada, who designed and built the engine, said to do.

Harry