40-50cc saw engine needed

[spacemule]

Don't many of the chainsaw conversion people machine the crankcase down? Seems to me weight would not be as big a factor in the larger planes for most applications as it is in the smaller planes--the engine is much less weight proportionally on the gas jobs than your average .40 size setup, no?

 

[HiOctane]

Flywheel is roughly same size as on chain saw usually.

 

[eric_271]

Mule airplane says weight aint that big a deal to him but he does want a light engine Anything I fly I want it over powered and no excess fat, in the engine or the plane. If its to much engine for the plane then throttle management is in order.

 

[eric_271]

Don't many of the chainsaw conversion people machine the crankcase down? Seems to me weight would not be as big a factor in the larger planes for most applications as it is in the smaller planes--the engine is much less weight proportionally on the gas jobs than your average .40 size setup, no?

Mule Until you get into the 40 and 50cc range the glow engine of the same cc size makes more power then the gas engine and as a rule weighs less then the same size gas engine. It also uses a lot more fuel then the gas engine and thats $14.00 a gallon compared to $2.50 a gallon for gas. The trend around here is a 50cc gas engine on a 120 size plane. If you want to run a big glow engine because of the power and less weight then $14.00 a gallon fuel wont bother you.

 

[AirplaneAnthony]

Eric has made some good points, but I plan on using electronic ignition from C&H. That will get rid of the flywheel weight. I am not as concerned about weight on the plane I am needing an engine for as I would be on a 3D plane. The Robinhood is based on the Curtiss Robin and is a big floater utility plane. I will tow up gliders and parachute jumpers and do candy drops with it. That is why I wanted the extra power. I have flown it with the engine I converted from a Stihl HT 75 pole saw. I got that engine down to the same weight as a Zenoah g-26 even with the flywheel. I am sure Eric can appreciate what I want to do by going to the larger engine. I am doing it on a plane that can take the weight of a larger engine. If I wanted the power and weight was critical then I would go with a glow engine. A Saito 2.2 cu.in. four-stroke weighs 38oz and has the power of gas 50cc. You can't beat that power to weight ratio.

Eric, I can see you are a big DA fan and conversions are not your thing. I just can't see paying $600 for an engine to have the lightest 50cc gasser. As you said, if I am that concerned about weight I will get a big glow engine and just deal with higher operating cost. I, however, like to do conversions and take pride in the fact that I can take a big heavy chainsaw and turn it into a comparably weighted gas airplane engine. I have converted a Poulan 3300 that was very light when pulled out of the saw. It was one that has the crankcase as part of the saw body. I am not wanting to do one of those again...it was a lot of work and I had to be careful not to cause a spark when grinding since the body is magnesium. I think the Echo 4400 and 510 are the lightest easy conversions. It appears most of the others will require some machining. The Stihl MS 290 looks good too.

Can anyone think of any other saws that the crankcase is not part of the saw body?

 

[Mange]

Jonsered 2040 could work.

 

[Mange]

I can post a pic of it if you like.

 

[AirplaneAnthony]

Please do.

 

[Lawn Masters]

How about the husky 350? wouldnt that work?

 

[spacemule]

Here is a link to a Poulan Pro 260 (40cc) I bought back in April for the purpose of modifying for RC. Alas though, my ambitions proved greater than my time, and I would let it go if you're interested. The crankcase is tiny, and looks to be perfect for modification. PM me if you're interested.

 

[Mange]

Here is Jonsered 2040.

 

[AirplaneAnthony]

Mange, that 2040 looks just like a Poulan 46cc that I have. I guess that would make sense since they are both made by Elux. How much time is on it? Piston and cylinder still in good shape?

 

[Mange]

I have no idea, it was in the pile i bought last. Looks good though.
I put it in the washer, so it might give a better impression now.

 

[Mange]

Not only are they made by Elux, they are made in the same factory, I think.
2040 say's Made in USA.

 

[Sylvatica]

A (very good) local small engine mechanic (fanatic) that I know has used Shindaiwa engines in R/C planes.

 

[AirplaneAnthony]

The husky 350 has the saw body as part of the crankcase. It would be less cutting since it is just the lower part of the crankcase, but still is not a pull out engine.