I also agree with Daves math.

Glow puts out more HP--pound for pound. But a gas engine has got TORQUE, and plenty of it.

I think glow engines are stronger--but only to a point. If you keep them wrapped up and keep a lighter load on them--they will keep going. But, if you slow it down by putting a big load on the prop (vertical), it falls on it's face.

If you get into the BTU of the fuel and all that crazy math, it seams like gas puts out more BTU than the glow, so you'd think gas would do more work. But, the glow engine is buring twice or three times the fuel of the gasser, so even though it's fuel has a lower BTU output--you get more power because your burning so much more of it in the same timespan.

I think........ [sm=spinnyeyes.gif] [sm=stupid.gif]

I used to fly the big glow engines. ST3000, ST4500, Moki 2.10, Moki 1.80, MDS 2.18--etc.... I had most of them at one point or another. They just don't have the pull. They just don't have the grunt that a gasser has. I could always tell when a glow engine was running out of power. Pull vertical and just go up. Even a Moki 2.10 will run out of grunt eventually and start to slow down. It's not running out of fuel. It's got a Cline regulator on it. It's just feeling the load of carrying all that weight straight up and the engine can't handle it. The load catches up with it and the engine starts to loose torque. You can hear it.

Not so with a gasser. Point it up and hammer the throttle. It just goes and goes and goes. The plane may start to slide back down if you don't have enough engine--but that gas engine will just keep on gruntin'. It won't sag or slow down. The prop will turbulate and the plane may slide back, but the engine just keeps on going.

Pull a big HUGE loop with a big glow engine. You'll hear it starting to groan just before you get to the top of the loop. Right when there is maximum load on the prop--you'll hear it groaning and slowing down. No torque.

Pull a big huge loop with your gasser. It won't quit. It won't groan. Listen too it. Tilt your head out and point your ear at it. No groaning. No slowing down. It's like the Energizer bunny. It just keeps going and going and going. GRUNT!! Thats what I love about gassers. So much torque.

But you'll still need a bigger gas engine to do the same work on a plane because the gasser doesn't burn near as much fuel and doesn't have the same overall BTU output.

To replace a 1.60 glow engine--I'd probably want a 35cc -- 40cc gasser. It's a bit heavier, but it's gonna pull the plane around like a ragdoll compared to the glow engine.