flyjoe540

does anyone convert stihl saws or are they too heavy\too much work .it was another freebee i've only seen a few posts
on stihl saws whats the concensus, is it worth doing or not?
It's old runs good no i.d. on size just wondering
I also have a johnserd same story I need to weed out the good, from junk im running out of storage space in garage.
any opinion welcome.

box car

I am doing a 23.9cc. Its out having EI installed right now. They maybe a little on the heavy side, will have to see if the RPM I get will off set that.
Ken

KenLambert

My Feedback: (107)

the stihl saws make good engines , jonesred also but some of the older ones are heavy, the 25.4 and 27 and such make good ones and are lght. here are a couple pics

Geoffinpdx

My Feedback: (5)

I'm a small engine mechanic who repairs Stihl equipment. At a recent service school the instructor showed a photo of a converted FS55 weed trimmer and commented, "This is NOT covered under Stihl warranty!" :-)

Stihl produces two different types of chainsaw engines. The homeowner grade stuff has the engine built separate from the main frame of the saw; the professional grade stuff has the engine and main housing all in one. Their weed trimers/brushcutters would probably be better bets for conversion than their saws due to weight considerations with the good saw engines. The new "4-Mix" four stroke/two stroke hybrid engines should make very good aircraft conversions, but I haven't gotten my hands on a good used one yet.

If you can find an eleven digit number on any part of your old chainsaw I can look it up and tell you what model it is, and whether it's current production. Contact me directly at [email protected]

KenLambert

My Feedback: (107)

I have done one of the four mix and weight is a huge factor

Geoffinpdx

My Feedback: (5)

Let me know what I weighs when it's finished. I'd expect the FourMix to be lighter than the Honda GX 22/GX 31, since they don't have the added weight of an oil sump. But then, on something like a scale WWI airplane with an extremely short nose, a heavy engine is a good thing. Try getting one of the big displacement Four Mix blower engines instead of the 30cc trimmer engines.

Shindaiwa also makes a big mixed fuel four stroke blower engine, but the ignition would have to be relocated or replaced, since it's at the bottom of the engine, and that makes for a very tall engine.
I was going to try to convert one of their 25cc trimmer engines to aircraft use, but I liked it so much I scrapped my 2-stroke trimmer and kept the Shindaiwa!

Back to the original chain saw business: Keep in mind that saws are designed to run at 10-15,000 RPM; string trimmers run at about 7,000RPM, which is about prop speed. While your mileage may vary, I'd expect better results with a blower or trimmer engine designed from the ground up to produce maximum torque at the speeds a prop turns.

KenLambert

My Feedback: (107)

the pic of the four cycle is a 69cc back pack engine ( four mix ) is weighed around 11 # ready to fly if I am not mistaken so the weight is an issue on the four mix engines even the ones on the back pacs blowers .

KenLambert

My Feedback: (107)

here is a pic of an old stihl cutoff saw 54 or 56cc it is on the heavy side but not enough to be concerned with.

flyjoe540

Ken
that last one looks big, is that engine curently in use ,in what airframe ,how about some numbers?!
weight ,rpm's that kind of stuff?

KenLambert

My Feedback: (107)

it is a 56cc I don't have any # , I converted it for some one else and he is flying it on a 84" yach however you spell it.

airbornrc

My Feedback: (9)

I converted a Stihl 031 50cc. There were 50 & 56cc versions. I got it to the same weight as a DA and on the same prop and tach it runs right with a friends DA in a side by side test. It flys an 84 inch, 16 pound extra very well. Some simple machine work can take alot of weight off these motors.

Mark

BillS

Your comment is very interesting and helpful. I have an older converted 69cc Stihl saw and a Stihl 57cc blower. The magneto flywheel on the blower is very compact. The flywheel on the saw is very heavy.

Bill

Ralphbf

My Feedback: (27)

There is a form where a guy is talking about 4 1/2 ounce flywheel with magnets 5 times stronger than stock.
I don't have the exact name but I have given enough info to do a search.

Captain Ramius

heres the light flywheel

[link]http://www.rcuniverse.com/forum/m_4031310/tm.htm[/link]

captinjohn

airbornrc: I would like to see a photo of that 031 Stihl. Thanks Capt,n

gottagofaster

My Feedback: (2)

let back upa bit here guys...

is the pic in kens post have the prop hub on the rear of the engine?

if so, this doesn't reverse teh effect of the prop does it?

thanks

KenLambert

My Feedback: (107)

it is on the front the mag is on the back

airbornrc

My Feedback: (9)

I will try this.

Mark

Antique

My Feedback: (4)

I converted 4 of the 64.9 Stihls...Two with mag, two with EI...Two mounted so that the shaft turned ccw, two cw, depends on which side you put the mount on...None weighed even close to 11 lbs, more like 6, with the EI lighter...Not enough more power than a G62 to bother with, the "four stroke has more torque" thing is almost non existent...The Stihl dealer told me the four stroke has 17% more torque...Could be, it didn't show up in the tests I did with the same props (and larger) used for G62....[8D]
And the Stihl costs $400 new....There's a lot of new parts to throw away when you get done.
The sensor for the EI was mounted on an aluminum ring on the front of the case behind the hub...It got hot enough running to disable the sensor...Changed the ring to G10 to insulate it, no more problem...

flyjoe540

mark
details,details you must give us details!for instance c.c., is that a "tuned" pipe.I like what I see,clean, neat,simple

KenLambert

My Feedback: (107)

RC it probably was more like six # I couldn't remember exactly but I knew it was heavy. Thanks for correcting me.

KenLambert

My Feedback: (107)

mark that looks a lot like a poulan 60cc with the gilrooni cylinder?

airbornrc

My Feedback: (9)

It's a Stihl 031 50cc. The muffler is simply a Coleman back packing fuel container with a couple of down tubes welded in and a end cap machined from aluminum. The muffler is very effective. I made the header from K&S pieces. The cylinder has Mahle cast into it. I machined the conversion parts, and turned down and thinned the cooling fins in my shop.

Mark

captinjohn

Mark: I got to hand it to you.....you done a very,very nice job. I got 3 chain saws...I think the Stihl is going to loose its saw parts....soon. Capt,n