ckangaroo70

My Feedback: (51)

After scrolling through a million post, and trying to do a few searches, I am wondering if I am the only person who has ever ordered one of these? I am building my second super sportster 90/120 and decided to give one of these SK 90 engines a whirl. My other SS 90/120 was equipped with a Super Tiger G90 which I think is a pretty good engine for the money. The exaust is the only thing I don't like about the ST's. So when I come across this cheap 90 size SK engine, I decided "what the heck", I will give it a whirl! I am not what you would consider a penny pincher, and I do own several high priced, good quallity engines, but I am always open to giving something a try if the price is low($90). My SK engine is yet to be delivered, so my question is there anybody who else who has purchased one of these, and what was your experience with them? Thanks!
http://www.kangkeusa.com/

Turk1

If you can make a search on this forum,you can find a lot threads on SK engines.I am maybe the first fan of those engines.I have 2 SK 50 and 1 SK 80 and Im very happy w my SK 50 s.(80 is still in box)I dont want to repeat myself one more time here( moderators will kick me out otherwise), you will be able to find a lot here after a quick search and also you can take a look at http://www.rcuniverse.com/product_gu...engine_id=1012
You can find other SK s along there.
Strongly recommended.

treedog

And i thought i was the only sk90 owner and a 60 too both new in box just ain't got around to using them yet Ok all u other cocka roaches come out of the dark corners he he[8D]

AMB

I have both an SK 56 amd 90 (both ringed) and converted to diesel with Aj Coholics head. The same chinese engine maker also-appeared as Blue arrow engines also after useing the improvementss paul ordered as they are good and i have had no problems except a bad bad carb which was replaced under warranty. they are I think a little better than GMS and Tower
a good value. I have the JEN 56s and 47 all suoer runners no problems if bought under the JEN, SK or Blue arrow labels name tag
you should have no issues martin

The first ones out a few years ago I thought was not the best quality I would not buy a used one from that times period

ckangaroo70

My Feedback: (51)

Thanks for the info.

NM2K

My Feedback: (14)

I still have my NIB SK .50 ABC and .80 ringed. If it ever cools down, I hope to get them on the bench for break-in and then in the air.

TestPilot6

I have an SK .90, too. Got it about a few weeks ago. I'm still building an airplane for the engine and will probably take another month before I'll finish it. Meanwhile, I've run the first 24 oz with 5% nitro PowerMaster and SuperTigre glow plug. Tech Support guy told me to make sure to run in rich 2 cycle, not 4 cycle like SuperTigre, to seat the ring correctly. I also used 15x6 APC prop by his recommendation, though the manual recommends 13x8. The first tank (24 oz) I ran at around 7000 to 7500 rpm. I enriched the mixture a few clicks in the early part since rpm started to rise as the engine was broken in. So far so good.

I started to lean the high speed mixture at full throttle but I had to stop and leave. I'll probably try setting the max and idle next week.

speedster 1919

My Feedback: (3)

I have a 50 and an 80. The 90 is suppose to be a bored out 80 . The 80 was very tight and did not like high nitro. Super Tigre OEM plugs are poor and and don't last that long. The SK is alittle hard to tune but they run good. They are not super power houses. That 15x6 is got to be too large a prop and 7500 too low for a 2 cycle. A 12x8 MAS will be the perfect speed prop .

NM2K

My Feedback: (14)

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Lately I have read of more ridiculous advice given by tech support people than I ever thought was possible. Who would recommend running a 15x6 on a .90 two-stroke during break-in, or any other time?

Ringed engines should be ran in a rich four-stroke during the first several tanks of fuel. ABC engines are ran in a rich two-stroke during break-in.

A 12x8 or a 13x6 would be about the perfect prop for breaking-in this engine. A 14x4 is okay too, once it has some time on it. You don't want to lug a glow two-stroke engine down much below 10,000 rpm at W.O.T. Gasoline engines are a different matter, their timing is adjusted for lower rpm. Adjusting a glow engine's timing is not such an easy matter and can lead to preignition/damage.

TestPilot6

Today, I tach'ed the SK .90. It idled great around 2200 - 2300 rpm. I got the following max.

APC 15x6 9400 rpm (1.75 hp)
MAS 13x8 10500 rpm (1.89 hp)
Zinger 13x6 11200 rpm (1.77 hp)

Parenthesis is the calculated horsepower by ThrustHP. 15x6 has the same loading as 14x8 and is within the range of props recommended to the engine by the mfr.

Very interesting. The tech support complained ppl just don't read the instruction.

Now I'm not really taking either side. And I don't know who is right. But I'm not quite happy with the max rpm I got. The engine is rated at 2.5 hp as opposed to 1.8 hp I got. Does this mean it will get better, or got destroyed by the break-in? Hopefully the mfr rep has an answer.

speedster 1919

My Feedback: (3)

Forget the MFT's stated max HP, most of the time it is hyped hog wash. 13x6 and 11,200 RPM is close too flyable and fast spool up RPM. 12,000 would be better and I don't care what your HP calculator says. Looks like after break-in your 15x6 RPM went up 2,000 RPM.

ckangaroo70

My Feedback: (51)

I think a 14X6 would probally be a good all purpose prop for this engine, but we'll see.

TestPilot6

Speedster 1919,

No. 7000 rpm was the rich 2 cycle full throttle and not the max rpm. I was getting about 9000 rpm to begin with. That's why I'm a bit concerned. However, I can say the mid range and the idle definitely improved. The engine runs very smoothly from idle to the top, except at idle, it kind of 4 cycles, but didn't seem to die when a sudden full throttle was applied. I did various transitions many times and they all sounded great.

I have 2 ST GS-40s and both of them give more than 1.2 HP, although the rated HP is 1.15 HP. I did use 10% OMEGA but that's not high nitro content. So that's where my expectation comes from.

Ken

Turk1

My SK 50 is on a heavy trainer Excel 2000(about 6 lbs.).Starts at first flip,idles great as long as you want.Transition is good.(I keep it a little rich for safety).At full throttle it pulls my heavy trainer -almost- unlimited vertical.(I couldnt test it so long to prove because I afraid to loose).Im using industrial methanol(means a lot water), full castor and 11x6 prop.Im soo happy with my cheap but flawless engine.Most of all very reliable,never had a deadstick during its about 6 hours flight time.I wonder if anybody could try it with famous Tower muffler?How about add on power with it?

speedster 1919

My Feedback: (3)

TESTPILOT Your now ready to pick your permanet prop (13x6) and your low end needle will need to be dialed in. My SK's did not like high nitro. I fly every engine I own on 5%

TestPilot6

I went through Tach Reading forums and discovered SuperTigre G-90 and OS .91FX are not doing any better than my SK. OS is rated at 2.8 HP and ST is 2.5 HP. SK is rated at 2.6 HP. But their actual max without any modification is around 1.8 HP, just like the SK I have.

I was also rather surprised many of them were tach'ing using 15x6. I guess after all it isn't that strange to run 15" props on .90 engines.

I'm thinking about changing the fuel to 10% Omega and see if it makes any difference. Glow plug is another element to consider. I don't have other .90 size engines so I can't really compare but the vibration and noise are much greater than .40s I have.

XJet

Lots of the current generation of 90-sized engines are run with larger props to keep noise down and because they have quite a flat torque curve (due to their narrow transfer ports and over-square configurations.

My ST90s give maximum usable power with a 13x6 prop. The power drops noticeably even if you go up to a 14x6 so I've never tried a 15x6.

ckangaroo70

My Feedback: (51)

This is what I have found also with the ST 90. It really likes a 13x6 prop. I have tried various props on the ST 90, but always went back to the 13x6 as it always seemed to generate the best performance with a 13x6. If the SK 90 will generate as good as performance using a 14x6 I will be happy, but havn't run my SK 90 yet to test some various prop configurations. The SK 90 is mounted on my new Super Sportster 90/120 that I built from kit, and once I finish getting the radio equipment installed I will fire the SK 90 up. It should be interesting to compare to my other Super Sportster 90/120 that had a Super Tigre 90 on the nose of it swinging the 13x6 apc.

Turk1

Just wonder to measure the distance of my clunk from carb when my SK 50 raising full nose up on air and found 8,5 inches.This means
my SK engine can feed(by muffler pressure) from about 8,5inches clunk ,nearly vertical-sure the tank surface will reduce this- but engine can have throttle up when tank gets about empty and approximately full nose up many times.

rustypep

My Feedback: (6)

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.

ckangaroo70

My Feedback: (51)

Lots of good info there. Thanks for sharing.

NM2K

My Feedback: (14)

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You are right. I was having a senior moment. Sorry about that.

buddek09

My engine on my trainer went bad and I was looking at a Magnum .46 XLS then I saw a SK .50 for cheaper and I was wondering what engine I should get

ckangaroo70

My Feedback: (51)

What engine do you have on your trainer that went bad? Remember that no engine will hold up very long to constant lean running. As far as which engine is better between the SK and the Magnum, I would have to say that I really could not say. I have never owned a Magnum 2 stroke engine. I have owned several of there 4 strokes and have been very happy with them. I am so happy with the way my new SK .90 is running, that I went ahead and ordered another one just to have another one around. So I have been happy with both the Magnums I have had, and the SK. The important thing to remember no matter which engine you buy is tune them correctly, and do regular preventative maintence. I will say that the SK .50 will be the more powerful of the two, but if this is going on a trainer the Mag .46 would probally have plenty of power as well.

NM2K

My Feedback: (14)

The only thing greater than watching a new Plane take flight, is the feeling you got knowing that you built it yourself. Support your Kit Cutters and Manufacturers!



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Responding to your signature line:

Ermmm, if I was going to get all warm and fuzzy about building it myself, I would have to cut out the parts too. <G>