Dean in Milwaukee

Got my harbor freight 26cc ryobi 4 stroker a while back, and finally had some time to begin fooling with it.

I stripped the heat shield stuff, the muffler, the flywheel and the ignition bracket and igntion save the spark plug, and got a weight of only 3lb 7oz.

This is much lighter than I would have guessed, the muffler itself being suprisingly heavy. I'm not yet sure if I want to go with a battery ignition, but it would save close to a pound of flywheel.

Performance at this point is hypothetical, but this motor is rated for 1 hp at 7k rpm, and the calc program I'm using says a 15x8 apc with 1 hp will turn 7600 rpm, so I'm going to assume a safe 7 grand rpm in real life, which should be about 7.5 lbs thrust and 54 mph pitch speed. A 16x7 should also work theoretically, making about 7200 rpm, 9.25 lbs thrust at 48 mph, but would require the motor to really make the full rated 1 hp at 7 k, not a tiny bit less.

I'm thinking the 15x8 will be enough to fly a 1/4 scale cub pretty realistically, but would appreciate anybodys thought on this.

Thanks,
Dean in Milwaukee

captinjohn

What kind of ignition are you going to use? Sounds like a fun experiment! J3 is a nice plane for that engine, I would think. Regards Capt,n

Dean in Milwaukee

Not sure who's ignition, have you any suggestions? Cheap is always good of course. As for the plane, I'm thinking perhaps the THE WORLD MODELS 1/4 scale clipped wing cub, probally in blue. Have to find out yet exactly how much its going to cost, but their 1/5th scale version is only $189, so I'm hoping it'll be pretty reasonable.

Dean in Milwaukee

captinjohn

Dean in M I bought a ignition from RCIGN1. I think its the best deal and he will fix it, if it ever quits. The price is right too. Capt,n

davewallace

My Feedback: (29)

Hi Dean,
I finished my Ryobi 4 stroke. It weights about 76 oz. with flywheel and coil ignition.I plan on trying glow fired E85 mix or regular glow, if I can make or buy a plug adaptor. The plug is special and very deep. I beam mounted the engine, so I can bolt it up to standard mounts. I havn't had a chance to run it yet, so I don't know how well it will run with the stock 9mm carb. The carb may be under jeted without the air filter. I took a couple pictures. I hope that this works, first time uploading.

Dave

captinjohn

Dave W: Sounds like that Ryobi 4 stroke is going to be neat on glow. If you can get a big glow carb that may be a way to see if its going to run good on glow. Good Luck.....Capt,n

foamcut

My Feedback: (40)

Dave,

Were you ever able to run the Ryobi 4 stroke on glow or gas / glow?

Thanks

davewallace

My Feedback: (29)

Foamcut,
I haven't fooled with the engines for a while. Teh very long reach special spark would make it very difficult to make a 10mm adapter. I thing EI would be the best ignition solution for weight savings. It would fire the plug every time. You will get ignition everyother revolution.

Dave