The plans show a G-62 , and say up to a 4.2 engine. I have read that one guy had a 100cc twin on this plane. I want it to have unlimited vertical performance and the smoothness of a twin. Is 100 or 110 BME too much for this plane. What do I need? Would a engine like the 75cc 3W strong enough to get me straight up until the cows come home?

There is a Lanier 1/3 Laser at my field with a 3W 75 and it has unlimited vertical.

I am also building a Liberty Sport bi-plane, it has a 94" top wing, it says that it should weigh 22lbs. the plans mention nothing about a engine size. One guy told me a 50cc but I think that there is no way a 50cc engine could pull this monster straight up. I really like to fly at half throttle and have the option of going straight up . I 've only know the regular glow size planes aand have been flying them for a long time. The gas plane size is great, but I have little knowlege about the engine sizes. I have dozens of plans of giant scale planes and am starting to bulid a few of them. Any of you guys that can give me some bench marks would really be helpful.

either the current BME102 or the Xtreme would be plenty for either plane.

I just finished a Fiberclassics 2.6m (102 span) Extra 330lx. Final weight, even with a BME102 on the nose (with canisters) was almost 27 lbs. Because of the canisters, though I realized a big power boost, and it's swinging a 28" prop at 6300 (HOT, only one gallon through the motor) and the little Fiberclassics is up, away and GONE out of sight vertical in a big hurry.

An older BME would be a better motor for the Laser, since the power would be a bit tamer and this is a substantially smaller plane than my FC330. BUt, also, there IS a left stick on the transmitter. On the bipe, you GOTS to have nose weight, remember, and bipes have short noses. I'd check CG for how much weight it takes to balance, then buy the appropriately weighted engine. . either a BME or DA100

OK.... I'm not going to argue with him, but I <have> to say that Kris has an exceptional motor compared to everyone elses account of the 102 - my 100 turns a 26x10 Mejzlik at 6500, a 26x10 NX at 5900, confirmed <normal> on RCFAQ.com, and with Keith Baker who claims only a 300-500rpm increase with the 102... 28 lbs with that engine is on the high side of where I would go with it, IMO, the 100/102 is best suited for the 23/25lb airplanes respectively.
In short, I think perfect for either application.

I have a friend with the 1/3 Lanier Laser ARF.

He's got a ZDZ 80 on it. It's got enough power to slingshot out of a hover.

And he's flying here in Denver at 6000'

Uh. .DesertRat. . I'm running tuned canister mufflers. . .they usually are good for 300-350 more rpm from the motor at least, sometimes more. . AND. . you have to remember. . the AM28-10 has a bit narrower of a blade than a Mejzlik or Menz, so it will RPM just about 100 rpm faster from the same motor usually. that adds up to about 400 rpm over what people are usually turning a comparable 28" prop with this motor, but using standard mufflers.

I said I wasnt going to argue. If you're going to quote numbers off a 28" prop, then by golly you oughta explain that your not getting 28" worth of thrust from the prop! I can get 6500 rpm out of the Mejzlik on my BME, but I get better vertical performance out of 5900 rpm and the NX.... my point is you really need to quote <which> prop you are using when you post RPM figures...

that is all.

heh. . that's funny Desertrat.. "not getting 28" of thrust". . A Menz 28" prop is ONLY 27.3" in diameter, their 26" props are 25.4. . the 30's are really 29.5 and the 32's are 31.25. . .kind of makes the whole Menz line of props a bit. . insubstantial.

I wonder if they are gtting their rated diameter in thrust?

I chose the AM because I KNOW it would rpm about 100 more than the Mejzlik (of which I have 2, just waiting till the motor breaks in a bit). Still teh footprint is 28" in diameter, although the blade area is just a bit less. I tmakes enough thrust to haul the plane straight up and a pretty good clip. . I did a snap, full roll and another snap on a vertical line and kept on going. I think that says a lot about this props ability to pull and provide thrust. right now, I think a mejzlik would have made the motor bog a bit more than I like, But. . past experience with an older version of the 102 showed a solid 6200-6250 rpm on canisters with the Mejzlik 28-10 after the motor was broken in. The Evo is substantially stronger than the older 102's, so I'm SURE this motor will happily spin the Mej 28-10 at around 6400, on pipes. Time will tell, of course.

I just saw the BME 110 in action on Todd Blase's Cap when I flew in Waco last sunday. It only weighs 4 something pounds. He was running a 27-10 prop on it. The owner of BME was out there also and I got to talk to him.

Since you will probably be concerned with weight when thinking about such a large engine in a 33% plane, the 110 would be great. Just have to wait until it is available for you to buy.

If not the ZDZ 80 would be good too.