Thread: Chainsaw conversion for 1/4 scale flying models

Hello Everyone, I am quite sure that my interest in chainsaws is very different than everyone else but I hope to obtain some feedback from experienced people in this forum.

As a hobby I build and fly ¼ scale WWII fighters and chainsaw engines happen to be perfectly suited for powering these birds. Most of the time flywheels are shaved and prop hubs have to be machine but outside of that stock chainsaw engines can be bolted right in.

Some of my work can be seen at http://photos.yahoo.com/bc/rcbird123...os.yahoo.com/.

The reason for this post is to obtain some feedback regarding which chainsaw engines, between 60cc to 100cc, are best suited for this purpose. The most desirable characteristics are as follows:

Compact design, in close muffler and carb configuration.
Magneto is bolted directly to the engine.
Low and smooth idle.
Smooth transition from low to mid range and from mid range to high
Ability to mount a flat back plate for attachment to a firewall.

There are a number of manufactures in the hobby that take stock chainsaw engines and make new crankcases and electronic ignitions but they also increase the price of the stock motor by 50% to 100%. Common motors used include Sachs and Quadra’s.

Any suggestions regarding engines that you feel would make a good power plant for a large-scale model would be appreciated. If you have something that you would like to sell me between 60cc to 100cc please let me know also.

Thanks

Norman

I dont know about now. But a while back there were some people out hear. Always buying engine parts for the Stihl 045.

I've seen a lot of the smaller sized models that use trimmer power plants...these have the advantage of not having the bar mounting, oil tank, carb housing/handle mount, etc.

Most Current chain saws would require a lot of work, as you allude to regarding new cases, etc. Some of the saws of 25 years ago might suit better; some of these had separate gas and oil tanks, and could be modified more easily, but we are also talking mostly old, tired machines that do not have the power and reliability you need without being rebuilt, or never were a very high performance model...such as many Homelite or McCulloch saws.

OK all the other guys will come after me, but what about the MODULAR motors. Stihl uses them in the consumer line, the 039 being 64.1 cc. I know other brands use them also, but not familiar with sizes.

Contact the Boeing Employees Model Airplane Club in Seattle Wa.

I am sure they have a web site or just call Boeing for thier phone number....This group has everything from props to jets. Hope this helps.

What about backpack leaf blower engines, they make a couple in 60cc+(Shindaiwa and Echo).

Originally Posted by Rotax Robert

Contact the Boeing Employees Model Airplane Club in Seattle Wa.

I am sure they have a web site or just call Boeing for thier phone number....This group has everything from props to jets. Hope this helps.

Good to see you back Robert. Are you all ready for Squim?
John

Originally Posted by Gypo Logger

Good to see you back Robert. Are you all ready for Squim?
John

I didn't know he was back, John. This thread is from 2002.

Hi Spacemule, I noticed that after I had posted, but it's ok. I was trying to pull him out of the woodwork.
He says he can't sign on, but I think that is BS. He was afraid of LJS and TFJ, but they are banned forever, especially since the recent attack on MB, so Robert needant worry. I mean, I would have stuck up for him anyway.
John

I know they are not as big as you may need, but the stihl 021,023 and 025 might be good ones to look into. The crankcase is a seperate contained part from the gas tank and bar assembly. Also the stihl 029 and 039 are similar. The homelite 150 pops into mind as well. Wow, these sound like big planes, got any photos?

There was old guy in Chicagoland building the bigest model planes allowed to fly by gov. regulations and I found guy selling left over parts after plane builder died.
This guy was using Husqvarna 61 and Husqvarna 281 engines. I still have some prop aluminum parts and one or two crank shafts. Clutch side shaft on the crank is cut off short, just long enough to fit bearing and seal on it.I think I still have e-mail address to guy, hwo sold me all brand new crank shaft and cylinder assemblies to fit 61 and 281 Husky saws.