I am thinking about getting into the rc engine conversion world. I thought I would ask the experts for their opinions before I went searching for an engine. I was wanting to know the following:

1. What would be the easiest, most reliable engine brand to convert in general?
2. Where do I find this engine on? (chainsaw, weedwacker)
3. How long does it usually take to convert?
4. Is there a website that will show you the step by step process graphically?
5. Will I need to order a conversion kit?
6. What is in this kit?


Thanks in advance.

How big of an engine do you want/need.
Ease of conversion doesn't matter if its the wrong engine.

tkg that is a good point but I think the easiest is the homelite 25 to 30cc and the ryobi 31cc

Easiest to convert is the Ryobi 31cc, you can usually find them for $69.95 at Wal-mart...it takes 15 minutes to convert them, and no special tools.
All you have to do is dis-assemble the weedeater, trim the back plate with a dremel and bolt your mount and hub on...
I get my conversion parts from www.wackerengines.com
Couple things to look out for...
1. Make sure it's the newer twin ring piston version (old single rings didn't have much umph).
2. Make sure the airframe has 1200 sq inches or more...and keep it light as possible.

Then, go have fun!!


Best of luck!
CrazyHerb
www.crazyherb.com

Well I decided to go with the Ryobu 31cc engine. How will I know when I go to Walmart if it is the newer twin ring piston version? Will this engine work on a Stinger 1.20? What kind of performance can I get out of this combo? Would you guys happen to have any step by step pictures of the entire conversion process? I am very new at this conversion stuff and would hate to screw up a perfectly good engine. I would really love to see some pictures. Thanks in advance!!!

Has anyone ever kept the recoil starter on a converted engine? I know it would add weight, but wouldn't it be worth the convience?

I would vote for the Ryobi if not for the rear carb, which make hooking up throttle and choke cable somewhat more challenging. Weedwackers, in general, are more difficult to extract the engine - often requiring reading some instructions if you haven't done one already.
Most of the weedies require some cutting and grinding. Even the Ryobi requires some "machining" of the rear plastic back cover. Last, the weedie carbs are pretty weezy and need to be replaced or modified to make good power.

My vote goes to the Poulan chainsaw engines. Extracting the engine is simple and straightforward. Once the engine falls out of the case, it is ready to eat. No cutting. Plus, you have a wide range of displacement to choose from - 33cc to 46cc. If you are going CH Ignition, get the 46cc. If you're staying magneto, the 33cc to 42cc ones work better. The OEM carb give good power and can be used as is, and many have butterfly choke valve built-on. Mounting is easy and more intuitive for folks who are used to beam mounts RC-style.

Homelite chainsaw are reported similar to the Poulans in ease of conversion, though I have no personal experience.

Just my $0.02. Actually, if I had put my $0.02 every time I played with a new conversion engine, by now I probably have enough to go to MacD to buy an icescream cone.

I won't knock Volfy's recommendation either.
For one reason... Chainsaw are MUCH more powerful than the Weedies.
A typical 42-46cc poulan will push 25 lbs thrust at least... (20-22 inch prop)
My ryobi on a good day may get 16 lbs thrust....(18 inch prop)

In the Ryobi's defense though, I haven't had a problem with the throttle linkage on the rear carb...straight shot to the throttle arm with a ball link...or nylon nosewheel steering arm..
http://www.crazyherb.com/BigPink/Picture015.jpg

Whereas, with the Poulan 42cc, I had to buy a special "rotator" manifold to get a straight shot linkage to the throttle arm....not a problem...just another bolt-on part..

My next conversion, by the way, will more than likely be a Poulan 46.

I'm with Volfy heading to McDs to get my ice cream too....

Find your airframe (Stinger 1.20)......... they are equally easy to convert but slightly different applications...ryobi will fly it fine...
Poulan will YANK it through the sky...

You need to take probably 1.5-2 inches off the nose of the stinger to get it to balance right with either motor...

OH YA! Here's a link to a photo-by-photo conversion of a ryobi!!
http://www.geocities.com/CapeCanaver...071/ryobi2.htm

Good Luck!
CrazyHerb

Herb, The Ryobi 31cc was my first conversion, so I have a special fondness for it. Because of it's unique RIRE configuration, I'll always have at least one in my collection for those narrow cowl long nose airplanes like PT-19.

BTW, I sold my 42cc Poulan precisely because I didn't like the non-straight shot throttle cable hook-up. The Poulan 46 OTOH gives a straight shot parallel to the thrust line.

A typical Poulan 46 turns a 22-8 Menz about 62-6400..the ThrustHp chart shows about 25 lbs thrust..Been there..
A G26 turns a Mejzlik 18-6 about 9000..the ThrustHp chart shows about 25 lbs thrust...
A spring scale on the plane with the G26 shows about 17 1/2 lbs thrust...Been there..
therefore, 25 lbs thrust from a Poulan, according to the chart, may be just a LITTLE wishful thinking...Anyone ever check out a Poulan for thrust with a scale ?
A 20-10 MA on a Poulan turns about 7000, shows a little less thrust on the chart..Been there also....

Once again RCIGN amazes me...
A wealth of information...
I like your static thrust meausrements with spring scale (real world meaurements)...awesome...I knew ThrustHP was off...but wow...that's quite a bit compared to spring scale...
I'm gonna have to get me a digital fish scale to try out with the RCS 1.40 I have on my GSP Katana...
Spinning a 16x8 Bambula at 9100 rpm....I want to try a 17x8 but it's not a very popular prop...or...maybe that 18x6!!!??
I've noticed the smaller gassers like G26/RCS like to spin up pretty good, so I'm happy letting the old RCS spin at 9K...performace seems to drop dramatically when you try to load them down....

I think my ryobi likes to be "loaded" though...probably in the design...(imagining the loads of your typical weedeater string/shaft/hub/and wackin' weeds).

Now I definitly would like to see "spring scale" measurements on the Poulans if anyone has them...
I don't have my Poulan 42cc mounted yet...but will test when I get a chance...

Thanks RCIGN!! Good Info!!
CrazyHerb

Have to say any saw from Sachs is a good candidate for conversio. 2.0 up to the 7.2 cube.

I did a Poulan 46 as my first conversion. I had LOTS of help from the fine folks here, and from the vendors I used for parts. I have it pretty well dialed in now. I REALLY like it, and am very happy I did it. I would not recommend it as a first conversion. The carb mount requires a fair amount of work to make durable. You should just plan on making a new adaptor plate, and following RCIGN1's method. It's not hard, but is a bit more work than some modelers I know would be comfortable with. The rest of the conversion is very straightforward. From what I understand, the Poulan 42 does not have the carb mount issues of the 46, though I don't have any personal experience with it.

The conversion experience is a fun side of the hobby. I wish my wife didn't keep such an accurate count of my engines/planes. I'd like to do a Homie 33, but have a rule of always building a plane for a new engine. I have NO ROOM for any new planes. Time for a yard sale I guess.

Hello All,
Great info here as usual. I am working on 25cc homelite (weedie) and 33cc Homelite (chainsaw). I contributed a little on the 33cc thread. As it has been pointed out, the chainsaws come with a carb with enough oomph and the weedwackers need a carb upgrade.................. well , my 25cc did anyway.
Both were pretty easy to do using information posted here. It would have been tough without it.

I would advise scanning through the threads devoted to the conversion subject. It is exceptional just how much can be learned in these threads. That's my $.02 (I get a charge out of the humor here too).

Doug

I didnt measure the thrust of a Ryobi, but when i put a Wacker engines muffler on it, it seemed like it increased the thrust dramatically, it definitely had a lot more power just by adding the muffler.

CrazyHerb...

How to measure thrust at the low-low...various engines on your planes of choice, with max pitch props...have your buddy stand with his ankles holding on to front of horizontal stab...start and throttle up... ...at full throttle for three mins...if he has 1/4 inch horizontal dents in his achilles, that's' about 12 tp 15 lbs.thrust with an 18 cc...if the dude turns ashy white and starts crying and his Reeboks are quickly filling with blood... then thats' a twenny five pounder or so...with mebbe a Ryobi or Homelite 32cc..

I'm no expert by a long shot, but I do so enjoy messin' with the little engines...I don't even fly yet...I'm too busy building airplanes that would go with my latest conversion...If your interested I'll let you know how to use a common house cat as an automatic orientation guage, or tachometer....Me bride thinks I'm nuts...as you all know that would be interpreted as my having a very high IQ...

Let me get a little serious here now...I am retired... 63 years old, and a seven year Parkinson's patient...I build and convert for therapy...some of my better medications I feel, are working in my shop...Again I am a novice at this...all I can offer are my experiences...

Ist engine...Weedeater 18cc...which is actually a shop trophy...ends up when cutting and grinding off extra shroud metal, I smooth cut away my magneto bracket...no s___! at this rate I'll be flying when Star Wars is real...Next was a Homelite 28cc...conversion stuff from Carr Presciion... plane is ME-109, 13 1/2 lbs; plan a llltle difficult to read as I got them off a Russian web site...wheeling a 16/8 prop at 1/3 throttle the lillle plane flys like a champ...can't wait till I feel confident enough to go it alone...

My choice of engines would either be a 28 cc Weedeateer off a Featherlite gas trimmer...or a Homeliete 32cc for bigger planes bigger engines?... I just haven't had any expeerience...yet...maybe next week...I thought the Ryobi 31cc was a convertor's dream machine with the carb working off that reed valve in the crankcase, and the muffler sittin' above it all in a line, would make for an easy mount to cover with narrow cowls...the problem I have with Ryobi is the garldarned crank and connecting rod are stamped metal talk about getting by on the cheap...I had one in a Spitfire I just finished but was knocking when I tried to start it...removed the back crankcase plate and saw the stamped stuff...the crank was made of strips of steel held together with what appears to be wrist pins.. bottom line ie when the crank shaft rotated it would hit the pins...thus the knock...wherin now sits a Homelite 32cc...

Some maybe helpful hints...

Use a drill press to drill series of inline holes to remove aluminum... seems to go faster than just cutting and rinding...

Save everything attached to engine... parts may come in handy some day...

Tighten propeller very securely... a back fire whenstarting can shear the magneto fly-wheel pin, which is cast aluminum...

Those zama carbs aren't Walbro... use a velocetiy stack to increase rpm...they'll work just fine...

If you pull the piston from head...be careful getting it back in you can easily pop the ring...

Reconditioned Ryobi grass trimmers at Harbor Freight for 49.00 plus shipping

Reconditoned Weedeater Featherlite trimmer from E-Bay 44.00 plus 14.00 or so shipping

When the traveling tool shows come to town, go early...good source for Weedeaters under 50.00

Lost the web site but McCullough sells engines outright rebuilds for 20.00 or so...some outfit in kansas City

Wacker Engines for converesion kits his prices arr lowest I've found and he could use the business Peter Faith owner...


Gotta little windy here so I'll sign off...


Thanks for everybodys help and hail to rc universe...


Remember "We're all here because we're not all there"'


Sethlakai


I used to have all the questions...and I still do...they're just different questions.

Hi

BULLSEYE

http://www.geocities.com/CapeCanaver...216/index.html
it is a site build by Joe Guzzardi, with photos, when I was a beginner, this open my mind, nice photos , numbers, for the Ryobi
I know you like it
Good luck
Jose

THANKS FOR ALL THE HELP GUYS