Building a GP decathlon 40. 2 stroke and 4 stroke engine chooses. what has worked for you.

Had an OS 70 4-stroker in mine and it was more than enough power.

Ditto on the OS 70. Great combo.

Did build one of those...Had an OS 46SF on it, with a J-tec inverted incowl muffler. Flew great. Careful with the CG, and do no spin if not a little nose heavy...took 2 1/2 turns to recover, Otherwise, great model. Landing gear a little weak, tailwheel is crap, better replace with spring leaf tailwheel bracket. Did use K&S Aluminium profile tube for struts, balsa provided was so hard, btut the plane flew great without struts, Also, my kit was from 92, so I do ot know what they changed since then, but the wheel axel was actualy screws, in orteher to attach wheelpants also, either you change the axels, or you put some brass tube on the thread where the wheel are gonna be placed. I did have some wheels that seized, locked, with some bad results.
Good luck
Al

Oh yeah, and if your kit didn't come w/ the updated addendum concerning the wing, make sure you include about 2 degrees of washout on each wing tip or you'll discover the meaning of the word tip stall.......

Mine had a SuperTigre 51, which provided plenty of power. A four stroke would be a nice touch. Much more realistic sound for a scale plane.

Eric

My buddy had one pre wing wash out, it was a tip stall monster. He finally gave up repairing it and cut it up for kindling

GP stopped making them.

Do kits appear for sale here or elsewhere ever?

If anyone has an unbuilt kit, I might be interested.

I have an ASP .61 2stoke in mine. Needless to say, it has plenty of power, and by all standards is very overpowered I'm sure. I built it several yrs ago(like 10+yrs). I can tell you about the tip-stall too... it happens very easily without the newer concept of the built in wash-out. Mine can be, and is a squirly little thing, likes to ground loop on take off, and will tip-stall if not landed with some power pulling it along. Other then those idiosyncrosies, it's a wild little plane that begs to be turned loose....definately NOT trainer like in the least....so don't let that high wing fool you for a second. Somewhat unique as well too, as you don't see a whole lot of them either. I've only ran across a few other ones in all the years Ive had mine. Good luck.

Kits are still around. thats why i'm trying to find out more about them. I have one coming. OS70 is the way i think i will go. just recently got back into rc planes, any other tips on this plane would be well received. also you's to know Pete.

Jim,

If you want to build a nice Decathlon, Citabria...there is the SIG..It is almost the same size as the great planes, but it is SCALE, has the barn door ailerons, proper fuselage profile, it builds lighter and it is not as vicious as the GP was. If I had to do it al over again, this would be my choice, The only major drawack I can see with the SIG kit is that the windshielf is not preformed, it is a piece of clear plastic sheet that has to be cut and glued in place, but nothing realy hard there.Pricewise, it is about the same, and a FS 70 would power this machine just fine
Al

Thanks Al.

Yes, I've noticed the Sig Citibria. I beleive SIG toned it down a bit by using a flat airfoil.

The squirrelly nature of the GP Decathon strikes me as someting different and interesting. I can't quite imagine it so I want to give it a try. I had it on my "want-it" list, then it was discontinued.

In my opinion the OS70 would be a nice choice for that plane. I've owned the OS70(was in another plane), and know they are quite a little power plant. Plenty of punch...and the power band(lots of torque) just might do that Decathlon good. Just watch for ground loops on take off, and keep some speed to it, and land on the mains with some speed. Yes, it's a bit different technique, one that you learn on the fly(pun intended), but know those things going in, and anyone would do fine. Just act on them accordingly .
I also used the Aerotrend(is that right?) foil-shaped tubing for my struts..and still to this day.. ...after several years have never flown it with them..

Matter of fact....here's a quick pic of mine....