Can anyone tell me if the Ryobi 31cc Conversions make a good R/C engine?? Also do you think it will fit within a 1/4 scale J-3 Cub cowl???
Thanks!!
Anthony

I bought the same engine and made a prop hub adapter and motor mount for it.
Thought it would be a inexpensive setup, turned out not that great.

With a master airscrew 16x8 black plastic prop, I was able to get approx 5400 to 5700 rpm.

Do not know if this is typical for this engine, just my experience on one.

I have a Tartan twin and 3W150TS for my other gas engines.
It seems like the engines need to be port timed to run in the rpm range we need.

Weed wackers do not need to turn high rpms or have lots of torque, if it loads up, back off the weeds.

My 2 cents, hope this helps.

Tony

I have never done a before and after run on a Ryobi. But the afters usually are a 18x8 MA Classic in the 6800-7000 rpm range.

I've done 3 Ryobi engines and all of the turned a 18-8 at 6700 to 7000.

nashcat

Mine runs about 6300 on a TF 18x8. But its also a 10 year old wore out engine that was given to me. Works great. The biggest benifit of the ryobi conversion (to me) is having the muffler and carb rear facing. Goes good in a slim profile fuse.
Edwin

I have a 1/4 scale cub with a older 28cc Ryobi. It is wiyh out a doubt one of my favorite planes. It has enough power to do endless loops. Before I put a smoke kit in it, it weighed 14lbs. She would almost hover, stay in one spot for 5 or more seconds before sliding. In my opinion the perfect engine, plane combo. She turns a MA 18 x 8 at 7000.

Hope this helps.

Peter

Peter,
I am also interested in adding a smoke system, which system did you use?? I am attaching a pic of the engine, is $145 including shipping a good deal on this engine?? Will this engine fit inside the cowl??
Anthony

Looks like it comes complete and ready to go. Like I said I pay about $120.00 can. but do all the work myself. That one looks like it has a more attractive motor mount and a nice prop nut to boot. Looks like a fair deal to me.

As far as fitting inside the cowl, should be no problem from side to side. The Ryobi's are a little long though and may take some creative work on the firewall. I placed my servos and battery in the tail to balance it out, but had to add no other weight.

I installed a T.M.E.. It's ok but heavy. I never had it not work if I make sure it is pumping or primed before takeoff. I bet with battery and mounting tray it added 12 oz. Then with the smoke fluid, well over a pound. The cub still fly's fine and looks and sound very realistic in the air.

Hope this helps.

Peter

Do a "smoke" search here in the forum for my efforts with smoke. It's cool!

AV8TOR

Thanks for the replies,
I will try to make up my mind before long, I will either go with the Ryobi or buy a 4-stroke.
Thanks!!
Anthony

Anthony

The Ryobi will work great in your Cub

I have 2 Stinger 120's with Ryobi 31s

I have a video of one of them at www.macs-rc.com look in the Ryobi link

It has a TME SImple pump smoke system with 16oz tank with fuel and smoke tanks full it weighs 18lbs

watch the video for how it performs.

Bob

Ryobi-bob,

Did you build the stinger any differently for the ryobi? Did you lighten the plane any?

Just curious. I have posted in the other thread, about mounting a G62 in a Stinger 120.

My stinger is a great sport plane with a G38, but the fuselage seems very heavy. I think the all up weight is 15 lbs.

The wing came out light, even with full length 80 inch hardwood spars.

thanks!

Bill

Bill

I didn't change much, I did not move the firewall, I did put the servos in the tail for the elevator and rudder and the batteries and radio behind the wing under the turtle deck.

The 16 oz smoke tank and pump are under the wing, the 16oz fuel tank is in the forward hatch.

I had to add 6oz in the tail to get the CG spot on.

The engine was a reconditioned ryobi 700r (short Shaft) from harbor freight $49.95, most of them haven't been run for mare than 5 minutes or so.

Muffler from Peter Faith at wackerengines.

I made the prop hub and mount.

I have less than $100 in the engine

I am very pleased with the performance and the reliability

I almost have a second one ready Cub Yellow with another Ryobi

Bob

Wow, it sure flies like it is light.

I moved my firewall back 2.5 inches for the G38. I used the flat plate mount on two firewall-width hardwood standoffs.

I used full length spars, 80 inch wing. My smoke tank is also under the wing. Fuel is in the nose. Three servos in the tail, radio and batteries behind the wing. I needed no extra weight to balance.

My wing is really light, but the fuse seems really heavy - might just be me.

thanks

Bill

I souped a couple up and I have them on a 1/4 DF Super Decathlon and a GP Super Sportster

Search youtube 5395r, RC airplane mtd (Ryobi) with port and polish. For instructions on souping them up.