crow

need advice.
How many modifications have to be done to get it fit to an aircraft? Is it worth of doing it?

thanks
Crow

MinnFlyer

My Feedback: (4)

Basically, all you need to do is to make a prop adapter to go from the output shaft of the engine to the prop. From there it depends on how the engine casing is set up for mounting, and throttle linkage. There is an Engine Conversion Subforum in the Engines forum. Browse through it and you'll probably find most of your answers.

mulligan

You can also count on some machinging to reduce overall weight. A new carb may also be in the cards.

- George

DBCherry

My Feedback: (4)

It can be done, many do, but I don't think it's worth it. The weight is usually prohibitive and you can buy gas engines in the 35 - 45cc range pretty inexpensively on eBay or at RC auctions.
Dennis-

Geistware

My Feedback: (16)

I would recommend that you send the engine to Ralph C. and ask for a conversion price. www.rcignitions.com

Ed_Moorman

My Feedback: (1)

It's not that hard to do, but you do need some knowledge of engines. I had a buddy who used to do it all the time. He would pick up a broken chain saw, blower of trimmer and in a few days have an engine he would sell. It takes a lot of hack sawing and grinding and you do have to make or buy a prop adapter. The mount is usually just an aluminum plate screwed to the rear of the engine.

I've seem him do 70 cc chain saws down to 15 cc string trimmers. There is a 50 cc or so, blower motor that makes a really nice RC engine.

Check on the engine conversion forum. There'll be plenty of data there. Some engines are easier to convert than others and you'll be able to find this out, too.

daniberry

I would also suggest that you buy a new aircraft engine instead of converting chainsaw engine.

DGrant

My Feedback: (4)

dani, you might take a note that this thread is well over 14yrs old... ... and if you hadn't noticed that, the last activity was over 14yrs ago also... Just an FYI there.

Leon23

But it doesn't seem logical to me. When the prop makes thrust it pulls the engine, so the shaft generates FRICTION with the walls of the engine, if it has to hold in place. So this adapter is probably connected to the outer walls of the engine, so that the shaft transmits the pull to the whole engine block and the prop is held in place only by the tip screw. That seems logical to me, but how can I connect that adapter to a chainsaw engine if the chainsaw engine block does not even have holes for bolts to be fitted with that adapter? Sorry for my terminology, I am not a native English speaker.

Leon23

But it doesn't seem logical to me. When the prop makes thrust it pulls the engine, so the shaft generates FRICTION with the walls of the engine, if it has to hold in place. So this adapter is probably connected to the outer walls of the engine, so that the shaft transmits the pull to the whole engine block and the prop is held in place only by the tip screw. That seems logical to me, but how can I connect that adapter to a chainsaw engine if the chainsaw engine block does not even have holes for bolts to be fitted with that adapter? Sorry for my terminology, I am not a native English speaker.

foodstick

There are engines that are easy to convert with almost no tools, I had some blower motors that you could unbolt the fan, add a washer, and bolt on a prop. It already had a prop like adaptor on it.

Other motors you will need extensive tools and knowledge to convert.

the 20cc motors and smaller will barely get out of there own way!

There are some motors out there that when done right are great. I have some Poulan 46cc motors that run hard . But I had to buy machined parts for them.

Here are a few problems with converted motors, almost all converted motors were timed to be easy to start and not make top horsepower, They are usually under carbedand the first thing to do is get a slightly bigger carb off another motor. Some even have an emission carb that has to be modified to even adjust the needles. Also many conversion motors have a bad throttle curve and idle way to fast.
That being said I have a few don't even think about converting any new ones..

But now the Chinese motors are pretty cheap and reliable...That is why the conversion forum has more or less died...

carlgrover

Not that it matters to the OP, but I converted a Ryobi 30cc weedeater engine to RC several years ago. It was easy and fun to do. The only thing I had to buy was a prop adapter which cost me $40. Might have got it from a guy here I don't remember.

Happy 14th anniversary to this thread.

carl

jester_s1

I miss the ingenuity that went with giant scale planes in the early days. My club used to host a giant scale fly in year ago. From what I've heard, it was an much a show and tell of innovative ideas on converting engines, getting enough servos attached to a surface, and scratch building as it was about enjoying the planes and the fellowship. You can't beat the current equipment for performance and value, but there was always something very cool about a person who had built a reliable powerplant out of something others would never have thought to use.