I just got back from the BARCS flying field in Richmond, California a couple hours ago. I was flying my RTF Avistar with the OS 40LA when another flyer showed up with an Avistar with an OS52 Surpass four stroker. It was quite an eye opener to see the difference in the performance of the two planes. While the top speeds of the two planes were fairly similar the four stroker had much, much better acceleration.

This totally blew my preconceptions about the 4c vs. 2c thang. I realize that the 40 LA is not a true sport motor and a 40FX would probably be significantly faster but the Surpass seemed to have half again as much low end and mid-range grunt. To top it off, if there was any significant difference in weight between the two planes I couldn't see it in the flying characteristics. Actually, the solid mid-range really helped the 4c pull out of stalls and loops much more effortlessly and gracefully.

Anyway, I'm a novice flyer and now I beginning to see why people like the four strokers so much:

1. Stump yanking low end
2. Solid mid-range
3. A really nice sound

....My two cents worth.

Big Mike

I also Like four strokes for the reasons you stated. The only draw back I can see is Price. I paid $329 for my OS 91 w/Pump. That's a big admission ticket. It is up to the individual Modeler to decide if the premium price is worth it.

I have one convereted to taildragger, wires on the back, struts on the front and put in a Saito 56. It was like a whole different plane. But I wanted more. So i moved up to a Saito 72 with a 12x6 prop. First flight pulled the firewall loose. Beefed it up some. Almost unlimited vertical, goes for a long time straight up. Takes off in about 10 feet. I believe it would hand launch by just letting go of it. It's just a lot of fun.

I've been flying my Avistar since mast spring. It started out with a .40 ABC schneural ported 2-stroke which flew it quite well. I eventually got hooked on 4-strokes and stuck a Magnum .52 from ebay for about $120. The weight difference was only about 1 ounce and actually didn't need any extra weight in the tail to balance it. The acceleration is much better and the climb is awesome! People at the feild say they've never seen a 4-stroke on a trainer. Then they say they've never seen trainer that flies like that. So the 4-stroke is well worth it the slightly extra weight and money.

Anybody run a Supertiger .45 on an Avistar? Nothing wrong with OS, but for some reason or other I like the ST engines.

Andy

I had a 40 fx on my avistar. I wanted to put a 4S 56 on it but then it totalled it. the 4s I'll bet is great on it. just fiberglass that center wing section and use lots of rubberbands.

i have a thunder tiger .46 pro on mine.. love it..