OS FS52 to much meat for a SIG LT-25 ????

That does sound like too much engine for an LT25. But, I'm not so sure that a 20 or 26 four-stroke is enough. That plane works best with a 25 sized 2-stroke. The OS 40 4-stroke would be more like it. The 52 will certainly make it nose heavy.

Jim - AMA 501383

What goes up must come dowowowowHOWN wrote:

You could use the 52 if you don't want to buy another engine. It would fly, and I'm sure that you would enjoy it. But if you want an airplane that flies well, get the LT 25 and a 25 size engine. The LT25 would be severely handicapped with the extra weight of the 52. I always try not to put too much engine on an airplane because I believe that light weight is the most important factor in whether a plane flies well, rather than having extra power.

You will also want a 25 engine later for the planes that you put in your small car in the future.

The OS .52 is not a particularly strong engine. Most good .25 two-strokes would give it a good run for its money, power wise.

While I agree that lighter flies better, I do not think that the OS.52 presents so much of a weight penalty that the model would not fly well. After all, this model is just a floater and will remain so, even with a little extra weight. Just move the receiver battery back to reestablish the balance point instead of adding lead to the tail.

To each his own.

Ed Cregger

I haven't run an OS .52 myself.

I have a TT .54 that I flew in a House of Balsa .40-sized Extra. It was OK. I put in an OS .70, and that was MUCH more satisfactory.

The TT .54 weighs 14.8 oz (419 g). I'm not sure whether that is with or without muffler.

My GMS .32 w/ muffler weighs 10.8 oz (305 g).

My TT .36 w/ muffler weighs 11.4 (323 g).

I don't have weights for any .25s. They might be fractionally heavier than the .32 or the .36, which (I think) are bored out .25s.

I agree 110%. With care in placing the battery pack, you probably only add 3 or 4 oz at most to the all-up weight of the plane. Given that it's a trainer, I doubt that 99% of RC pilots could detect the difference in weight.

My own guess, since I assume that the TT .54 is more or less equivalent to the OS .52, is that the difference in power will be noticeable and fun.

And Guus doesn't have to buy a new engine.

Yes, exactly.

If you say so. ;o)

Marty

P.S. I started breaking in the MVVS 1.6 gasser last week. I'm going to finish the break in on a huge trainer, all things being equal. Then I'll go to work on the 2.15. :o)

Marty

"Martin X. Moleski, SJ" wrote

That's great, Marty. I wish you the best of luck with those two engines, not that I think you will need it.

Ed Cregger

Adding 4 ounces to this plane would be about a 6% weight increase. It is true that most folks wouldn't notice the difference, but those of us who pay attention to weight would probably be able to tell (including those who actually move the throttle stick around during flight). Especially if instead of the 52 you select a particularly lightweight

I guess what we are really talking about is acceptable performance.

I'm not a glider pilot, so the extra takeoff and climbing ability provided by the OS .52, coupled with the ability to fly in a little heavier wind than a lighter model will tolerate, just might provide an enjoyable change in performance. I like to hot rod trainers. Always have.

Your approach is sound for a given result, as is Marty's and mine.

Ed Cregger