when i was down at perry this year,i picked up an older GP sporster .90. 70+ span,built probably 20 or more years ago,it was built and covered with fabric and dope,then painted. this mobile lumber pile weighs in at almost 12 pounds RTF.anyway,the reason i bought it was because it was full of good ballbearing servos,fuel tank,everything but rx,and engine. not a bad buy for $40 bucks! so,the guy said he flew it with an old wore-out o.s.61 2-stroke. well,when i got it home,i didn't want to have to do a bunch to it to put an engine on it,since it had hardwood rails to mount motor,so i put a NIB TT.61 pro/12x6 MAS prop on it.never been run,unwrapped it from tissue and bolted it up. everybody that saw the plane/engine combo,said it would never pack the plane,a crash waiting to happen. well! to everyones suprise,it took off in about 20 feet,and climbed out at about a 60 degree angle!!! and in the air it is fast! got a friend there with a CG tiger2,with a ST .51 on it,and i can out run him!!!easy!! and to boot, the engine has about 4-5 tanks through it,and we have yet to touch the needles,it was that close out of the box! i love this engine,a real powerhouse,and cheap!