dirtybird

My Feedback: (5)

I recently obtained an OS 61 FX.
I see no ring in it. Is that an ABC engine?
I am thinking of converting it to gas & ignition.
Has anyone tried that?

1QwkSport2.5r

It's probably ABL. Nickel plated brass liner, aluminum piston. Not a good candidate for gasoline as its a tapered bore engine and gasoline burns too hot I think. I'm no expert, but I wouldn't burn gasoline in any ABC/ABN/ABL/AAC engine.

NikolayTT

...also the 10cc engines on gasoline might deliver power which you get from 5cc glow engine on glow fuel + penalty of heavy enough ignition system and battery for it. I would not consider going to gas with any engine smaller than 26cc because gas makes real sense for at least 40cc and even bigger displacements, best from various points of view seems 80cc. Cheers, Nick

dirtybird

My Feedback: (5)

Well to each his own. When I started with this hobby I flew gas engines on ignition with less than 1/4 the power of the engines we have available now. They flew.

NikolayTT

Sure, they flew but since those times the engnes got lot better as you wrote and we ... got older (I started in 1965...) ... I hope you will agree that greater power-to-weight ratio is always better for any (even a junky) airframe - it just flyes better especially in aerobatics and it is lot more exciting even for sport flying. Power-to-weigh ratio is maybe newer going to be enough in aviaton. I just made some experiments for up to 100cc and came to the conclusion (valid for 2012 and maybe for some few years more) that below 5cc seems better to use Electric, Glow seems best for 15-26cc two stoke, and gasoline about 80cc; fourstroke is kind of exotic ... indeed this is very subjective and still well supported by the total power-to-weigt ratio of the whole airplane.

Sport_Pilot

But they were floaters and flew real slooow!

dirtybird

My Feedback: (5)

I flew control line in the '40's. At that time speed fliers were getting close to 150mph. Not many RC fliers get that speed now. Only pylon racers.
I flew acrobatics. It was a long time before RC fliers matched the acrobatics I did then.
I currently think its a lot more elegant when an airplane flies on its wing rather than its motor.
I think the 3D maneuvers done today look more like someone threw a cat in the air than an airplane flying.
But as I said to each his own.
I am going to sign off now. The first reply was what I wanted to know. The other posters are just garbage. Why is you cant get a straight answer without someone attacking your purpose?

NikolayTT

... because it suppose to be a help to tell also how much sense makes the purpose too and hopefuly save time and effort for better purpose unles someone find sense in doing irrational things...all in RCU is an exchange of opinions freely...or we better tell you "go,go..and now see what you have done..." No hard fellings, just enjoy the chat

Turk1

Dirtybird, I have a 9CC(.56) ringed gas engine (NGH).I have 12000+RPM s with no name 11-6 props on bench.
 As you might know Evolution has just begun to sell very similiar but ABC(non ringed) 10 CC gas  engine and seems folks are happy with it(but it needs time to see about ABC  construction  results)

proptop

My Feedback: (8)

I've got a .61FX...IMO it gets a bit bad mouthed sometimes for being a bit weaker than comparable or contemporary .61 sized engines. That might be so, but mine turned an APC 13 x 6 at 11,500 on 15% Powermaster...not too shabby I think.

Being ABN though, it might not be a good candidate for a Gas conversion??? You could give 'er a try and see though...but if it doesn't work out, you probably have other engines in your stable to try it again on?

I've been able to pick up several "previously owned" .60-.61 size engines cheap, because a lot of people are buying .75, or .91's in the same size case. I kinda like the old .60's...and after re-reading the recently resurrected thread on Baffle piston engines, I have had to dig some of them out to have another look at the "inventory"...

NikolayTT

Importantly: - How similar/different is the Gas-Diagram of Gas engine vs. GlowFuel one for max efficiency ? And also, compression ratios ? Those two issues make a very good Question, should you even try such conversion because you might need to change the Gas Diagaram and that is not trivial home exercise, correct ?

1QwkSport2.5r

The problem with gasoline in a tapered bore engine is simply that the higher combustion temperature of gasoline would most likely cause the liner to over-expand and cause a loss of piston seal. I'm not saying it won't run, I just don't think it will run well for long.

How many gasoline engines has anyone seen that wasn't ringed?

proptop

My Feedback: (8)

Those were my first thoughts when I read about the new Evolution 10cc...although it is ABC (correct? ) not ABN. I don't think an ABN engine would hold up well at all, but???
I guess we will have to wait and see how the Evo 10 does...longevity speaking...

The carb and ignition components from the Evolution 10cc I suppose could be purchased seperately, and installed on any number of Glow engines...(hint hint ) It ain't gonna be done me any time soon though...$$$ sort of thing [&o]