ductedfan

Good Evening... Could anyone tell me which conversion engines have two rings??? I'm looking for maximum torque!!! Thanks...

DF

COM

I think most of your chain saw engines have two rings and some of the high end weed trimmers like stihl and husqvarna.

Charlie

tim220225

My Feedback: (4)

Two rings will not give you extra torque. They may give you more compression but even that may be marginal. I have done many conversions, some with two rings and some with one and have seen very little difference. What does make a difference in torque or performance is the porting and the timing of the ports. Of course a good prop will make even a lazy engine perform a little better. For my money I like a good Echo brand engine. The older ones had better porting but I have done newer ones that run just fine. My memory tells me that even my DA-100 has a single ring FWIW.

av8tor1977

My Feedback: (6)

There might be a very small gain in compression on an engine with two rings, but any power increase would be offset by the increased ring drag. A single ring engine will produce slightly more power all things being equal, while a dual ring engine might last a bit longer. That is a moot point though, as one could never fly enough to actually wear one of these engines out...

AV8TOR

Ralphbf

My Feedback: (27)

I have a 40cc Echo blower engine that has 3 rings.......
imagine 3 Bowman rings.....

combatpilot

I have a 40cc Echo blower engine that has 3 rings.......
imagine 3 Bowman rings.....

you really only need one and may be much better than 3 but i really hate to get into all that again. i dont care how many rings you got. more rings dont garuntee a good seal. you could have 4 rings with a worse seal than a single ring with a great seal. condition of the parts is everything and the only way to know how good a seal you have is with a leakdown testor. man i really hate to go into that again.

Ralphbf

My Feedback: (27)

I simply brought it up as a point of contention.
Echo makes pretty darn good stuff, and somebody there thought that 3 rings were the "Hot Ticket".
I was surprised to see 3 rings and the point about 3 Bowman rings was supposed to be absurd.

Fact:
One good Bowman ring is all anyone would need.
The proper amount of oil in the gas will increase compression with out loss of any horsepower.
“I found this out running chainsaws with 100 to 1 oil. 75 to 1 developed more power and ran stronger."
We will never run a RC gas engine enough to see the longevity on a 2 ring engine.
Not many people fly at full throttle, so a few hundred RPM means almost nothing.
The right size engine on the right plane and you will have power to spare.

*********** ***********
Pick the plane you want to fly. Find out how much nose weight others have used to balance their plane.
Pick an engine that weighs enough so you don't have to add weight and make sure it turns the correct size prop for your plane.

Hint: Planes that had radial engines need lots of nose weight.

I love gas planes. They are the most forgiving and most fun to fly and easiest to maintain.
And if you are diligent enough to build your own, it it's even better.