I bought a used SPE 26. Had to replace the crank shaft because it was bent. Had trouble running because gasket covered about 1/2 of the pulse hole to carb. Once I figured that out, with needles set at manufacturers specs it starts easily even hand proping, has smooth idle, good transition and smooth full power. Idle rpm is about 1,500-1,550. With 18-6 wooded Master Airscrew prop max rpm is 5,850. Manual says they got 7,850 with a 16-8 prop. Is this what I should expect with an 18-6 prop. Pulled the plug and it was nice dark gray color and with it running good otherwise I don't want to screw with the needles much.

Its on a Great Planes Stearman, weights about 14.6 lbs. Havn't had a chance to fly it with the weather we have been having. I hope this is enough power.

I tried 8 props on my CRRC 26 and tested with a fish scale
to try and hover a TWIST 150 at 11.5 lbs...

Wound up with a Zinger 16x5 at over 14lbs...
It will hover then direct into an iverted flat spin..
Then turn the SMOKE on...

Walt...

More than likely your intention is to assist, but when someone asks for help by posting a specific set of questions, why not answer directly if you can rather than go telling him stuff that will in no way assist him in his quest.

Karol

WHAT IS WRONG WITH YOU...

He was asking prop sizes, weight and RPM...
Power to fly his plane...

Sorry to have wasted your time....

Absolutely no need to aplologise. Maybe my level of comprehension has gotten worst with age but nowhere in your post do I see an answer to any of his questions which referred to a specific engine and model.

Karol

I have a spe26. I'm using an APC 17x8 and getting about 7450rpm.With a Xoar 17x8 , rpm was about 7300rpm.I acquired it from a friend who couldn't get it above 6900rpm on the same prop.I changed the carb to a larger bore, changed the ignition to an RCexl and changed rings to a Bowman. I used an OS160 muffler after some work. I reckon I could probably better rpm with the supplied muffler but I wanted a quieter setup and easier mounting. It was in a 95in candy bomber which probably weighed about 12lbs and flew with authority.
I think a 16x8 or 17x6 would be better for other applications.Al the spe26 in the club ran a 17x8 wood at 6900~7300rpm,definitely not a power house.The compression is pretty light compared to other engines of similar displacement like the CRRC and MVVS thereby the poorer performance.

Thanks for the reply. I leaned it out with about 1/8 turn. Now its pulling 6,300 rpm, with an 18-6 prop. Flew the plane today (snow melted). It was tail heavy and a hand full. Guessed wrong on CG. But seemed to have enough power for my purpose. But at full throttle it started missing. At part throttle it didn't???? Any suggestions??? Runs fine on the ground.

Sounds like maybe it's a bit too lean now.

Karol

To give you some more rpm's to compare to I have a Spe26 with a larger carb (11.1mm) and Rcexl ign. I have only tried a Xoar 16x8 so far and I was getting 8400rpm. I wanted to try a 17x6 and a 18x5 but the weather is too cold now until spring.

Thanks for the help. I was inspecting everything while moving the batteries to just behind the firewall to over come tail heavy problem when I found that the insulation was worn off the wire to the Hall's sensor where it was rubbing on the metal standoff mount. I think I found the cause of my miss. Why did it run fine on the ground and only start to miss while airborne. Murphy Law. I made careful use of tie wraps to make sure this does not happen again. Went by the local hobby shop to get some small stuff and saw that the price of glow fuel was $32 per gallon. I knew there was a reason for going through all this trouble getting the gas engine installed and sorted out. I've ordered a 17-6 prop and will see how that works. Maybe not until spring unless the skis I ordered for the plane get here. Snow today, more snow on Friday and then more on Sunday. Maybe I should move south.

I'm not sure that chafing to the insulation would cause a high speed miss unless it was very severe, as more than likely that sort of damage would show up as a radio interference problem due to the reduced shielding thus increased ignition noise, but then again what do I know, you could be quite right.

Karol












i know cause an increasa in ignition noise.

Mine spins apc 16/8 17/6 @ 8000+ rpm, original ignition.