Usually you just have to examine the engine and see. Engine conversions
don't have to cost much, if anything, you might need to fabricate some metal
bits though. Here is some thoughts:
If you leave the clutch in, you should be able to disengage the propellor at
idle (easy bellylander).
One thing that I've been considereing is a drive shaft pusher setup,
probably a wing. The idea being that you can use a more efficient wing with
less sweep with the motor in front, and the relative "safety" of not leading
with the prop.
If you can saw your weedwacker off at the right spot and get a bearing and
prop adapter on there then you can just bungee/zip
tie/hoseclamp/hotglue/whatever the whole thing to your aircraft :) Of
course driveshafts and clutches add weight :(
Try to keep the fuel tank in the same relative position to the carb.
I converted one with CH ignition and jag mount/muffler, and another
with just a prop adapter I got on Ebay........
On Sat, 27 Nov 2004 08:28:08 -0800, Geoff Sanders
Do yourself a big favor and don't even venture into this. Unless you
have a few hundred dollars laying around that you don't have anything
else to do with. I, regretfully, went down this path... Motor mounts,
muffler, ingnition, etc. etc. etc. I had the engine in a large
Decathlon and it flew it ok but I wasn't completely happy with it.
Pulled the Ryobi out, with all the junk associated with it and put an
OS 1.60 in the plane. About half the weight and twice the power and a
whole lot less trouble.
So unless you're completely bent on doing this I would suggest another
path for your endeavor. If you MUST go to a gas engine, buy one
already made for R/C. On the other hand, going through the process
with the Ryobi was kinda fun and I learned a few things along the way.
For me, it is now one of those things I've done, got the experience
and moved on to something more practical. Do some math and figure out
how many flights you'll have to make to offset the cost of what you're
doing with what you will save in fuel costs. If you'd like me to
answer any more questions you might have, please feel free to drop me
A few hundred??? Where do you buy your stuff, and can I sell it to you? I
converted a Ryobi weedeater engine for about $5 of bar stock aluminum for the
prop extension and a few hours of lathe and grinder work. The mount was
already there, 4 bolt hole flanges on the back side of the crankcase.
I had to buy a muffler, but I'd would have replaced the stock muffler on a R/C
gas engine anyway. If you have access to a lathe and a little bit of machine
shop experience, it's cheap and easy. The whole thing cost me $65 for the
weedeater (sale at Big Lots), $5 for the Al barstock (local machine shop) for
the prop extension, and $35 for the muffler (hobby shop), and $2 for 4 10-32
bolts and washers to mount it with (Home Depot).
Mine turned within a couple hundred RPM of a Zenoah G-23, the same size as the
Ryobi. Response was good and idle was excellent.
Glow, huh? You must have mega bucks (as you say) "laying around" for fuel.
For reliability, give me gas in the larger engines any day. No flameouts,
reliable idle, almost no adjusting from day to day, easy starting, and MUCH
cheaper to run.
"There's a Hun in the sun!"
email@example.com (Dr1Driver) wrote in message
You didn't mention an ignition system which adds to the cost. Magneto
is ok I suppose but adding electronic ignition sheds a lot of weight
which is highly desirable with the Ryobi. As for the fuel, the 1.60
uses less than you'd think and it is safer. And no need to have a
fire extinguisher available.
It's great that you converted yours so cheaply. But not everyone has
access to a machine shop and if you have to pay someone for their
machining it ain't gonna be cheap.
Bottom line is, if you do it right, it will cost more than buying an
off the shelf engine ready for use, gas or glow. And if you're
looking for any kind of performance glow will always have more power.
methinks "do it right" is a highly subjective term. It may be that the
fabrication involved is minimal. Perhaps the output shaft is already
threaded and just the right bolt/spacers needs to be utilized and some sheet
metal pop riveted into a muffler using the existing flange. The electronic
ignition is a bit more challenging, but just as scratch building an airplane
has it's rewards, so do all things that require a bit of ingenuity.
I have been wanting to try a gas conversion. have to motors already. wo
a 35cc motor on ebay fot 7 dollars and bought a ryobi leaf blower with
31cc and some guy heard that i was doing this little project a nd gav
me a broken spline weed eater that started right up. now with thes
engines they come in a varity of settings the Ryobi is the hardest t
adapt because the muffler and the carb are located it the back of th
motor making it difficult to mount in a cowl. its sticks out way t
far. so i talked to the guy at WWW.Wackerengines.com . he told me tha
the WEED EATER feather lites is the best.
carb on one side muffler on the other and machined for light wight. an
his parts are the cheapest ive seen. there like $30 for the self d
conversion kit and $25 for a pitts muffler where else have you seen
1/4 or giant scale muffler for only $25 dollars and smoke system ready
i will be putting one of these converted motors on my hanger9 25% Edg
540 as soon as it warms up here. hope this is another lead for all yo
guys out there looking for the cheapest way to enjoy the hobby. He
beats spending $499 for the same motor you can get for $100 to $150
Keep on flying and save money on GAS instead of Nitr
View this thread: http://www.rcgroups.com/forums/showthread.php?threadid0341
Why do you say that? The squat, almost square shape of the small gas
engines like the Ryobi and Zenoah lend themselves perfectly to large,
round cowls, like the Fokkers of WWI, and the AT-6s of WWII.
Back in November 2004, Walt asked the question of the cost of conversion of
a Ryobi 31 cc. For my part, I have done this conversion and I have a great
engine for less than $150.00 (less than half than comparable "model
airplane" gas engines). With that said, I just read a review of the Zenoah
G26 in the latest issue of Fly RC mag. Guess what? My weed cutter Ryobi
conversion turns a 16x10 prop at a higher RPM (8,100 vs. 7,260) and idles
lower (1,400 vs. 1,860) than the G26. And my tests are at 5,500 ft altitude
with 15% thinner altitude, which knocks the crap out of engine horsepower.
As for weight my Ryobi is almost 1/2 pound lighter (51.1 vs. 58.3 oz.). I
should add that I added a homebuilt electronic ignition and dumped the stock
one pound flywheel/coil assembly.
Granted my $150 total cost doesn't include some of my labor and my friends
machining (I owe him a lunch) and my 31cc is 22% larger displacement that
the G26 @ 25.4cc.
Therefore my observation is that the engine conversions are at least
comparable to other gas engines in their displacement class.
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