I just finished breaking in my first SK, a SK 50, and I have to say I am a convert. Two of the guys at the field had success with them so I relucantly gave it a try on new Ultra Stick 40 which weighs 5 lbs 1 oz (after its first diet). For $60 it was worth a gamble and delivery was quick. Where to start...well Ray (if I remember right) who is the engine tech for Kangke/SK told me it will swing a 12x5 APC at 11,750 and said that is what he uses. I used all APC props on this engine. I wanted to see this myself before repeating it but after a couple of tanks I was able to replicate that number easily on a rich setting. My engine was pretty tight out of the box so it took a full gallon of fuel before mine really settled in right. The engine didn't want to stop when cut off on the break-in stand after a couple of tanks so that is why I originally called Ray to confirm the stock low needle setting. One of the other guys had a similar problem but not as bad as mine but it eventually settled in. Ray told me to be patient and to lean the low needle until it stopped and the transition was perfect. On the final 1/4 gallon, it did just that. I was frankly afraid I had an air leak somewhere but patience proved me wrong. That said, I was getting a reliable idle from the start and easy starts but once broken in I got a real nice 2,100-2150 idle with smooth transition and great fuel economy. All this on 10% nitro (Omega). The plug was a OS No. 8 and 2.5 inch plastic spinner with metal backplate. I was going to play with different plugs but once it settled in there was no need. I was starting to get impressed.

We flew it with the 12x5 and it liked the prop. It was a good blend of speed and pull so Ray was right on the money. I am guessing a lot of folks are using the recommended 11x6 (perfect for most .46's) but don't realize it will like swinging the bigger prop. We tried a 12x4 on the fourth flight and got a few more revs and a bit more vertical with less speed so with the thick wing I think this will be my prop. I don't want a lot of speed on that wing and I want more pull for hovering and 3D. I am going to try a 12.25x3.75 to see how it likes that. I bet that will get around 12,500 so that might be the ticket. The engine has improved with every flight so it may take a few more tanks before I settle on the right prop. I typically hand start this engine by bouncing it back off of compression by twisting the spinner with the throttle set to high idle and it usually starts on the first flip. A few times I don't think I primed it enough so I just hit it with the starter and it immediately started. I was getting more impressed.

All I can say is you have to be patient with the break-in and the low needle setting but if you are...you are in for a nice surprise for the money. I went through a gallon and one plug before I got it right. The tank seemed to go forever and I let another flier I trust fly it who is a great 3d'er and on less than 1/4 tank he threw it through a few g's, pull-ups, hovering, etc. and we couldn't get it to quit so that confirms what Turk1 said. He flew it until it burned off the fuel completely and deadsticked it from 300 or so feet. We kept going verticle at the end to kill it and then did flat spins down and then back up again...lol. We had to stop going up a few times when it got hard to see....haha. After six flights it has not died once or given me any trouble. I am going to take some readings this weekend on the 12x4 and 12.25x3.75 and put a timer on my flight. The flight we intentionally deadsticked I have to believe was over 15 minutes and we did run it full throttle for a while to hear the noise of the Ultra Sport wing...hehe. At this point, I was a convert. I will buy more SK before anything else unless it is a Saito. An OS .50 is almost three times the money. IF you want more power than the Sk 70 is only a few more bucks and just use the throttle. The other guy is going to use two of these 50's in a Wing Mfg P-38 and that says something about the reliability.

Time will tell how these hold up (liners, bearings, etc.) but parts appear to be readily available and easy to find on Kangke's website. I haven't tried the tower muffler but the stock muffler was noticeably quieter than the other one we had on hand running the pitts so I am sure the Tower or MAC may be less restrictive and give a few more revs. He was running an 11x6 prop and comparing the two in a vertical climb wasn't even a fair comparison and his speed wasn't that much better in level flight. He stalled out vertical and mine kept going and going and going...haha. Fun stuff. Frankly, I am happy the way it works now so I am going to leave the stock muffler until I need to shed some nose weight. They also have a 1.10 and 1.30 size getting ready to come out so if you want more power....there you go. I wish they would do a 1.60-1.70 (hint hint to anyone listening from Kangke). The manual is a weakness in my opinion but if you can get through the switchboard to the engine tech you will find a friendly person who speaks clear english to answer your questions. You will know what I mean if you call the main number but everyone is friendly .

Good luck and don't hesitate to give SK a try. Up to this point I was running OS and TT two strokes.