I have a Trainer a Right Flyer 40 (for 40-52 engines) 63" span , The engine on the plane a .46 magnum is in bad shape and needs to be replaced, I have a brand new KB sporter .65 and would like to use it on my trainer, some guys at the field say it's a good move, while others say it's too much power, what should I do?. I've been flying Solo for the last 6 months Thanks David

Put the engine on... and don't use full throttle.

Yes... its a fair amount more power than the aircraft needs. But if you have the self-discipline to NOT fly at full throttle, the airplane will be fine.

You can use full power for a fast climb rate... that's OK. Full power in a tight loop will rip the wings off. THAT is why its too much engine.

By learning power management... you will actually fly better in the long run. So if you manage the power and keep the wings on... its a very good idea.

The K&B sportsters were an inexpensive series of plain bearing engines. It definatly will have more power that the .46, but it shouldn't be to excessive. This is probably a good time to discover that the throttle stick on your transmitter is more that just an on/off switch (Unless you want to get into warbirds).

When I got my LT-40 I had the recomended .40 in it. After a bit I replaced it a Fox .50. The Fox was just a tad heavier than the .40 and made a big difference in the LT-40's performance. I use throttle control all the time while flying, reducing the power to about 3/4 once leveling off after take off, and often back it off to slow it down and just "drag" it around in slow speed. The extra power is very nice for quick, steep climbs, and I always chop power on the downside of a loop and bring it back on when level. There are 4 Lt-40s at our field and the other three have .40s aboard. I've flown the three .40 powered, and I find them a bit sluggish, but of course with the extra "go" of my .50 I have the edge there. If you do use the .60, practice throttle management, or there will be times your plane will be overstressed, possibly with some bad results. If that .60 will run nicely just above idle, it could slow fly that bird all weekend long. Of course there are those who fly full throttle always. Have fun.

Why not set the pushrod so that it wont open up 100%? If it were me I think I would end up trying to push it too much so I would have to put a physical limit in order to stop that left thumb!!!

I have set the throttle linkages to prvent the throttle from going to 100% before.

Generally this sounds like a good solution... but if you need to tune the engine, you can not easilly retune the high range.... you have to over-ride the limit so you can get full throttle in order to do the retuning correctly.

Make sure you balance your plane after the change.
I bet you there is a significant weight difference in the engines
Luis

I have a supertigre .61 ringed version in my arrow trainer and i have not too much power at all.Even though i just learning to fly ,fellow at the club advised it.I had to use a half of stick of lead on the teal to balance it out but that want's big of a deal.And about limiting throttle travel-if you get computer radio you get a 'travel rate" on all of your servos.
Good luck

Why bother is my question. I'm sure you will be able to do everything that you need to do with your current engine. If I were you, I'd simply get another airplane that would allow you to advance to the next level. Fly the trainer for all it's worth and when you're ready to move on, move on. Keep the trainer for that relax sunday flying feeling but that's it... keep the current set up and get another plane that will propel you to the next level... of course, when you're ready!

I am going to go against the grain here. I say that the 65 Sportster is a bad choice. Do not get me wrong I like 65 Sportster's. They are an under appreciated, under used engine. They are light and fairly powerful. But they like a real big prop. They do not take well to a short prop at high RPM's. My feeling is that you will run out of ground clearance. And the Sportster is kinda wide. You may have to do some major surgury to get a mount in there to fit the engine. If you must use the Sportster try the built in mount. They have (or had ) a mount built into the back of the rear cover. I would try an OS or a TT or even a new magnum. I believe the mount holes on all 3 of these engines in the 40-45 size are the same. Good luck with whichever way you go. BTW I feel the Sportster wiil not be too powerful for the plane. Just some size issues.

Mark Shuman

I'm surprised to hear that the 65 sportster is a light engine. I have a 45 sportster and it's a fair bit heavier than my 46FX... I'm saving it for something that needs a lot of nose weight like a slow poke...

As for the trainer, due to the weight and size issues of the 65, I'd ****etaboutit... either get yourself a decent new 46-52 or pick up a decent used one to keep the trainer going...

As for the 65, run it up on a test stand and take the time to break it in properly. You might find it'll be a good match for something like a 4*60 or Tiger 60.....

Addition: I've got a 65LA that was in my first trainer (Superstar 60). After burying it with the aid of a Hobbistar.. it's been laying around for a while. Now I've discovered that it still runs nicely and turns an APC 13x6 @ over 11,000rpm it's going in my Tiger...