ORIGINAL: rustypep
Spend the $60 plus shipping and put two to three gallons through an SK 50 and if you are not happy with it I am sure someone here would be willing to buy it used as long as you take care of it. It is reliable and has good throttle/transition and I use it for aerobatics/minor 3D in my UltraStick. Mine idles very well. I also own a new TT 46 Pro (bought at the same time) that is in a six pound pattern plane (old Hobbico Spectrum) and I am not getting the type of numbers you mentioned at 425 ft ASL on 15% nitro. It has a tunnel for a tuned pipe that will be my next step. The weight of the SK 50 is 16.6 oz but off hand I can't remember if that included the muffler. I don't think it does. An OS 55AX will probably outperform it slightly but at 2.5 times the cost.
ORIGINAL: XJet
I'm at 380 meters (1135 feet) ASL and I run just 5% nitro with 12% Cooper's Plus C oil and a Tower Muffler.
What I'd really like to see is how well the SK's throttle and transition. I also wonder what the all-up weight is?
If they're as torquey as its' claimed and if they throttle/transition as well as a TT they might make a good 3D engine.
I'm sorely tempted to try one but they just look identical to the Tiger Shark 56 that I bought a few years back. That engine was an utter dog and soured me to that particular style of Chinese engines -- although my other Chinese engines such as ASP/Sanye and GMS seem to work just fine.
I recently bought the SK 50 and installed it on a Phoenix Decathlon after break in. Previously had a Mag 52 4 stroke in it turning an ASP 12X6, but it bothered me to be at full throttle most of the time. The SK 50 flies the plane with the same prop, but with reserve throttle for up lines, much improved handling. I have been experimenting with different props, and today, I put on an ASP 13X6N. WOW! It gives incredible smoothness to all maneuvers, the plane flies a bit slower and with complete authority and very solid in all attitudes. Sort of blows my preconceptions as to prop sizing! Tached at 9500 rpm.
Fuel is cool power 5%.