Hi Guys

I am a 35 year old newbie who is just starting out in this hobby and I have a really simple question. I am just waiting for my nice new SIG LT-40 ARF to arrive (reccommended to me) and I have been offered a free OS FP40 engine which, while older, has NEVER been fired up at all (the guy who offered it to me said he got it years ago but never used it). As I understand it, the FP was the engine that the LA replaced and as such is/was OS's plain bearing economy engine. Would this engine work with the LT-40? I have spent the day looking around and have seen people recommending the likes of .46 engines and race bearing engines and I am wondering if I should forget about the FP?

Any and all input appreciated.

The FP will be fine -- just not very exciting. It is at least as good as the LA & many pilots consider it better than the LA.

It will definately get you going. Don't worry about it. The LT 40 will work just fine with it. Worry about modifying things later, just learn to fly the basic stuff for now, you'll be happy with it..

I will say it depends. If you fly off of grass, then you may not be able to get off the ground. If you fly off of a hard surface, then you probably can fly, but you will be very short on power.

I can't offer an opinion on the FP(They are from before my time in RC), but have flown an LT40 with a 46LA and with a 46FX. Now, keep in mind that I fly from a relatively small field surrounded by trees (Actually it's "TREES!!!!"). After take off, you have to start an almost immediate climbing turn to clear the trees at the far end of the runway and continue climbing on the down wind leg of the circuit to get over the trees at the far side of the field. When I flew with the 46LA, take off and climb out was sometimes a little more "interesting" than I was really comfortable with. I replaced the LA with a 46FX and the difference was quite impressive... there was a lot more margin for error and things were a whole lot less "exciting" on take off.

I will admit that some(all) of the climbing ability(or relative lack thereof) with the LA could well have been due to my lack of skill at the time(There some who tell me that I still have that problem!). Also, I still fly the LA (but on a smaller airplane) and it has been a good performer, so I'm not trying to knock the LA.

What I would suggest, is talk to some of the more experienced guys at the field you'll be flying at and ask their opinions of the FP40/LT40 match. You may find that it will work, or you may find that they'll suggest a larger engine.

Good luck!

The engine will work if the grass is short and you have a long runway. If the grass gets tall or the runway is short then go for a 46 in either OS or Thunder Tiger. The 11" prop gives you a very noticable increase in power over the 10". 46 size is getting to be considered standard for 40 sized planes because the cost is almost the same and the extra oomph can be really handy at times. A lot of flyers are starting to jump to the newer 50 engines to give their 40 sized sport planes high performance .

That engine will be just fine. If you have tall grass, going to bigger wheels, or better yet a tail dragger configuration with bigger wheels will take care of it.

Thanks guys. The comments are very greatly appreciated and I'll mull it all over. Hope to be able to catch up with some of the guns at the field next week and get their input as well.

Cheers.

I have both a 40la and a 40fp. I think the fp has more power and yes th40fp will work great with the kadet

The way I see it is that the price is right so why not try and see, you have really got nothing to loose

I agree with the earlier comment to convert the plane to a tail dragger. This will reduce drag both on the ground and in the air. The nose gear on most trainers typically makes even ball bearing .46s look weak. The nose gear on the LT-40 in particular tends to make the nose squat which puts the wing in poor angle for takeoff. This is one part of the LT-40 that in my opinion doesn't live up to the quality of the rest of what is a terrific plane. Not to mention the plane looks a lot better without the nose wheel.

I have been very happy with my LT-40 taildragger conversion plus wheel size upgrade:

GP "scale tailwheel assembly"
1.5" tailwheel
.60-sized dural main gear
Dave Brown Lite Flite 4" wheels

It probably doesn't even need up elevator to taxi or to start takeoff, but I do it anyway so as not to lose the habit.

I converted to taildragger before I started, but it is not commonly advised. I felt confident in the quality of the instruction. It hardly requires any rudder input on takeoff. And I think it looks better, too.

-Jeff

Montague is correct, you'll have no problem, even in grass. Of course larger wheels are always an advantage, especially for the newbee.

I will also add my vote for yes. The old FP's were just fine. A heck of a lot better than the LA's. The 40 will pull that trainer just fine. Take the engine and use it, it will be ok.

Mark Shuman

Just looked like a good place to throw in a photo of my LT-40. It has a GMS .40 on it with an 11X5 Prop.