trainer engine size
 

I am new to the game and am learning on a electric glider and have built and flown an LT 40 with OS 46FX. I have a new in box OS 32 (older ball bearing model) that I would like to use on the LT and move the 46 to another plane. The LT trainer is supposed to fly with a .30 in it but I am concerned about the lighter weight affecting the balance since it is already tail heavy w/o added weight. Can the smaller engine be moved forward considerably to balance the plane? Will the .32 be enough for a trainer? :confused:

trainer engine size
 

Most of the LT-40's I've seen would probably fly on a .25, given sufficient skill and patience.
(perhaps even a .15, given a calm day and sufficiently patient pilot)
It will fly on the .32. The takeoff rolls will be longer, and you'll have to
watch the airspeed a bit more, but it will definitely fly.

See if you can adjust the battery location to get the CG forward, if it really needs it.
Yes, you can mount the engine far forward on the mount. You can also buy a "heavy hub"
to replace the propnut. They're generally brass, and good for a couple of ounces.

trainer engine size
 

In general the plane will fly within the recommended engine range.

I however was allways taught that chosing an engine in the middle to upper end of the range was the way to go.

The smallest recommended engine would be powerfull enough to just get it airborne and putter around.



The LT-40 is a good trainer with a wing that generates a lot of lift, why don't you try it and see for yourself how you like the performance.

Some people think a .46Fx on an LT-40 is overkill others don't. It's really a matter of flying style and skill. Lots of pilots today rely on flying off the engine instead of the wing. nothing wrong with that but it does lead to the misconception that a good flying aircarft has to have a power to weight ratio of better the 1:1

trainer engine size
 

A few lead weights could be added to the nose also.

But I think I hear something else in your question. It seems to me that you want to build another plane and power it with the 46, but still fly the LT-40. I would say go for it. The 32 will still pull the trainer, and you can have another plane (IE New Toy!) with a good 46 in it.

trainer engine size
 

Moving the engine forward will not appreciably change the CG.

The other methods have already been mentioned. (Battery and heavy hub)

Just wondering, is yours the kit or ARF. My ARF with a 46 FX balances with the battery AFT of the servo tray.

32SX....
 

The 32SX is a great engine and turns a 10-6 as fast as an FX40. It is lighter and you may have to canopy glue some lead weights to balance. Unless you are flying off a paved runway, I wouldn't go any smaller for an engine. The LT40 is on the heavy side for a trainer and even a 40 has trouble getting it off the ground if the grass hasn't been cut in a while. :D

Re: 32SX....
 

I agree about the 32, My brother has one and outperforms a 40 bushing engine and rivals the BB40's but don't agree about the Kadet, There are a few at my club and one has the OS46FX and the other has a OS40LA and the LA is a weak engine right out of the factory but lifts the Kadet with no problems on a grass field, Perhaps it is a prop choice but his does good. The OS32 will be fine, My brother orriginally had his on a SlowPoke and that one dwarfed the LT40 but pulled it just fine, A lot more docile but enough power to fly it but you won't have much left to pull you out if needed but will be a gentle flyer, Just try to move all the stuff inside to the front for balence and use a nose weight to avoid adding much to it.


Dauntae

trainer engine size
 

Should be fine, add some weight to the nose if you must. Trainers will fly with very little power, however if ,like most other fields I've flown off of, is rough and has long grass, you might have trouble.
As far as building another plane, get a Goldberg Tiger II. Excellent plane to learn aerobatics. A .46 will be perfect for this plane.