Ryobi
 

7650 with a 16x10 apc. Just lightened flywheel and larger carb and aluminum jag muff.I also like to remove the block to cylinder gasket and replace it with rtv :) . This increases compression by bringing the cylinder approx. 27 thousands closer to block :)

Ryobi
 

27 May 03
Ryobi 31 2 ring piston; turned flywheel; reed valve stop .125"; electric junction box muffler; run time less than 1gallon fuel
Dyna Thrust 18-8 5940
MAS Classic Blk 16-8 6600
APC 16-8 7620

disassembled cleaned all screw holes and bolts, made .005" brass exhaust gasket. LOCKTITE everything.

Ryobi
 

Hi guy's;

I have a Ryobi 26cc and get the following with mod. muffler, stock flywheel, larger carb and enlarged ports.

18x8 ma. 6900 - 7000rpms
18x6 ma. 7440rpms
17x8 apc. 7290rpms
16x8 apc. 7800rpms
16x6 apc. 8000rpms

16x10 zing. 6700rpms
16x8 zing. 7200rpms

I have done two conversions now this one and a Stihl 54cc.
so I am no expert. But both engines do not like zingers. I don't listen to hype about diff. props, I just go by results. I have put a fish scale on the ryobi and all the thrust dropped when using zingers. Down to 9.3lbs with the 16x10.

I now fly the 18x8 ma. on a 14 - 15 lbs clipped wing cub and before I installed the TME. smoke kit, she would hang on the prop for 5 - 8 seconds. Just a tad more hp. and I could hover :D . I tried other props too but got tired of typing :rolleyes: . Hope this helps.

Peter

RE: Ryobi
 

I tacked a new box stock Ryobi 31cc string trimmer with straight shaft and got 8100/8200 RPM. Nothing was disassembled or touched not even the carb adjustments. The test was no load except string in the trimmer head.

Eventually every prop imaginable will be tested. I may reassemble the other engine back to box stock and check the RPM. Do you know the RPM of maximum torque? Does the magneto limit the RPM?

RE: Ryobi
 

My ...had forgotten this thread..
Same engine as above w/ older style head, Walbro 167 carb, CH Ign
APC 16-10 prop, different DIM exhaust deflector : 8350 rpm
APC 16-8 prop " " " " 8950-9100 rpm

A torque curve would be nice.

RE: Ryobi
 

With no load (string head off) a stock Ryobi 31 cc engine will tack 11,000 RPM rather easily. I stopped at 11.000 but it would have gone further. No RPM limiter exists on this engine. It might be a candidate for a pipe. Now I really wonder what the torque curve looks like.