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Anyone Flying SK engines?
After looking at the threads, I've seen a really long one for SK engines, but I want to know if anyone (besides the few on that thread) are using/flying SK engines. The website shows some pretty good prices. Just curious as to whether to drops some $$$ for an relatively unknown engine.
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RE: Anyone Flying SK engines?
I'm flying an SK90 and I've been very happy with it, no issues at all and never a deadstick. I won't hesitate to buy another one when I need an engine that size.
Dan |
RE: Anyone Flying SK engines?
Dan- how was your break-in on the engine. After reading the thread(s) it looks like its not a major "powerhouse", but I'm looking at putting one on my P-40. And maybe save a few $$ at the same time.
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RE: Anyone Flying SK engines?
I have an SK50 and I'm disappointed with it. It runs three minutes and knocks out. I've run it on stands, in planes (15 dead sticks in a row) and still it won't run at odd angles. Runs good at mid and high (but not low idle) when level and on a stand. Three minutes off the starter in a plane and silence even with the low throttle set way up. Seems to be getting air leaks at low and in maneuvers, leaning it too much. I've had the help of the club engine guru (hours) . . . nothing. Same model/tank/mount ran a TT Pro-46 prior and a ST G-51 after with no problems at all. I still have the SK and may resume working with it, but set it aside last fall in disgust.
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RE: Anyone Flying SK engines?
I bought an SK80 engine to try. It ran poorly and never developed what I would call reasonable rpm, certainly not good enough to attempt taking the test plane into the air. I had it at the field several times and wasted many hours trying to get it to run properly. I gave up and gave it away at one of our club meetings early this spring. The pilot that took it home has good experience and he hasn't flown on any planes so far. In this size range all I buy are Tower Hobbies 75 engines now. :D
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RE: Anyone Flying SK engines?
I broke mine in exactly per the instructions that came with it and had no problems. It wasn't excessively tight to begin with though. I'm probably not the best judge of how powerful an engine it is, it's my first .90 and I'm using it to overpower a .60 size Daddy Rabbit so I really have nothing to compare it to and the plane certainly doesn't lack in the engine dept. I'm running mine with a 14x7 3-blade prop due to ground clearance issues, and that's the only prop I've had on it, other than during break-in. I'll try to remember to put a tach on it the next time I have it running, but I'm pretty sure I'm somewhere in the high 9000 rpm range with that prop.
Dan |
RE: Anyone Flying SK engines?
ORIGINAL: Charlie P. I have an SK50 and I'm disappointed with it. It runs three minutes and knocks out. I've run it on stands, in planes (15 dead sticks in a row) and still it won't run at odd angles. Runs good at mid and high (but not low idle) when level and on a stand. Three minutes off the starter in a plane and silence even with the low throttle set way up. Seems to be getting air leaks at low and in maneuvers, leaning it too much. I've had the help of the club engine guru (hours) . . . nothing. Same model/tank/mount ran a TT Pro-46 prior and a ST G-51 after with no problems at all. I still have the SK and may resume working with it, but set it aside last fall in disgust. |
RE: Anyone Flying SK engines?
I have an SK 50 and 2 SK 90s. All run extremely well. The only dead stick I have had was near the end of a tank when I flipped a Twist 60 around and I guess the engine sucked air. The one on my Ultra Stick 60 never quit until I did a hard snap and the whole tail section came off. It quit on imnpact.
I also corresponded with the SK tech about the engines. They were designed with smaller ports for more low end torque. The ports are not large enough to supply fuel for high rpm. If you are looking for speed, this is not the engine. As far as I can determine, Kangke, the US distributor, had them made to power their scale and 3D planes. The best prop for the 50 is a 12-5. The best prop for the 90s is a 15-6. I tried 4 15-6 props, Master Airscrew, Master Airscrew Scimitar, APC & Zinger. I liked the Scimitar the best. The 90 has some low end grunt on the 15" prop. They are very easy to start and do not bite as the timing is more conservative than an OS, for example. The larger engines are ringed, but also have a tapered bore like an ABC engine, so they must not be run in a 4-cycle. The ringed break-in is very much like an ABC break-in. It takes 5 tanks of fuel. I ran it religiously on all 3 engines and set the low end on the 5th tank. Mine will idle for a long time, then snap to full power. When I had trouble with a Tower .75 with a rich mid range, I swapped in one of the SK 90 carbs (they are the same size and bore) and it ran perfectly on the Tower. The engines may be flown after this, but they keep gaining power for maybe 3 gallons. SK did have some problems with burrs on the carb rotating barrels that would hang up in the aluminum carb body. Kangke will replace the carb if you get one. I just took a small file and touched up the burr. Once the carb is rotating without the burr, it is excellent, in my opinion. Both the idle and mid range are great. I have both idled and run half throttle for a full 60 seconds on the bench and then snapped to full power cleanly. That's the same thing my OSs will do, so I can't complain. I have been meaning to see if the 50 carb will fit a Magnum .52XLS. I had the 50 on a Big Stick 40 for break-in, then on an original swept wing sport acro plane. Never had a bit of trouble, but I always ran a 12-5 prop. I bought the first 90 to check out the brand. After I ran it on the bench and then on a plane, I went back and bought a second one and the 50. I figured the price would go up. As for the problems, I can't find any. Last year, when the thread started, a few people were having leaning out problems. When they changed to a 12-5 on the 50 and a 15-6 on the 90 with 10% fuel, everything corrected itself. The guy from New Zealand, I don't know what engine he has. It sure doesn't sound like the SKs I own. The same outfit makes the blue JBA engines. These are ported more normal. The SKs from Kangke in the US may just be in the US only. By the way, the numbers don't match the actual displacement in most cases. 50-.525, 70-.75, 80-.80, 90-.91. |
RE: Anyone Flying SK engines?
I am very sure that the models are identical all round the world.
I had quite a few problems when I first used an SK - Then I followed the instructions. As Ed has stated, They are designed for low end torque and are not high speed engines. My first one is a 40 (That I don't think is available as a separate purchase - it came with an ARF) it swings an 11/6 APC prop at around 9800 rpm on 15% Nitro Coolpower fuel. That engine It came with an additional head shim - which I installed to stop the detonation caused by the higher Nitro (It definitely needed the extra shim installed). Maybe the US sold ones already have the extra shims installed. Because I was so impressed with the 40, we also now have 2 x 50's, 2 x 90's and 1 x 130 in our hanger - all have the additional shims installed and all run happily all day on 15% coolpower. The only deadstick problems I have experienced with them was the 40 because the ARF that it came with had the carb located about 1" above the tank centreline. It would run happily upright but as soon as it went inverted, it would deadstick (yes I know it is all about the mixture richening). Ironically the ARF was a Kangke one. I lowered the engine (The thrust line was too high anyway) and that problem disappeared immediately). |
RE: Anyone Flying SK engines?
I have over fifty flights on my Sk 50 and it runs great. I am still using a 12x5 prop on 15% nitro with no problems. This engine starts every time just by flipping it back off of compression by hand after it is properly primed. The engine gained a little power over the course of the first two gallons of fuel so a little patience is required during break in. Otherwise, it is a good value for the money.
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RE: Anyone Flying SK engines?
1 Attachment(s)
ORIGINAL: Ed_Moorman I also corresponded with the SK tech about the engines. They were designed with smaller ports for more low end torque. The ports are not large enough to supply fuel for high rpm. If you are looking for speed, this is not the engine. As far as I can determine, Kangke, the US distributor, had them made to power their scale and 3D planes. ___ SK did have some problems with burrs on the carb rotating barrels that would hang up in the aluminum carb body. Kangke will replace the carb if you get one. I just took a small file and touched up the burr. Once the carb is rotating without the burr, it is excellent, in my opinion. Both the idle and mid range are great. I have both idled and run half throttle for a full 60 seconds on the bench and then snapped to full power cleanly. That's the same thing my OSs will do, so I can't complain. I have been meaning to see if the 50 carb will fit a Magnum .52XLS. A fast model (Loved the ARF, hated the engine). When mine hung up at the carb barrel the servo managed to pull the four dimples out and tear the throttle arm loose. Luckily, I was able to do a loop and kill the engine. :eek: Images of the same plane with a ST G-51 I may give them one more chance . . . but probably not while Thunder Tiger or Super Tigre are still in business. |
RE: Anyone Flying SK engines?
Send an e-mail to Kangke. They'll replace the carb. They did one for me. They did want the serial number on the lug of the engine, probably to track the lot number for quality control.
Look, everyone knows the Chinese engines don't have the overall quality of the Japanese or Taiwan engines. I paid $60 for my 50 and $100 for the 90's. I can stand sending one carb back for the savings. And, from what I've heard, the problem has been corrected in the US. |
RE: Anyone Flying SK engines?
ORIGINAL: Charlie P. I have an SK50 and I'm disappointed with it. It runs three minutes and knocks out. I've run it on stands, in planes (15 dead sticks in a row) and still it won't run at odd angles. Runs good at mid and high (but not low idle) when level and on a stand. It exhibited all the same problems as yours and today it quit at exactly the wrong time in a gusty cross-wind (I was running a 12x5 prop at the time too!). Goodbye one plane. I remain unimpressed with the SK50 and consider them to be a "cheap motor" with few redeeming virtues. The SK90 on the other hand is a beautiful engine -- albeit not as powerful as an ST90 but with much better throttling and handling meaning that I'll be buy more SK90s rather than ST90s from this point on. |
RE: Anyone Flying SK engines?
Engine .50 SPECS
Disp (cc) Engine .50 SPECS Disp (cc) 8.14 Bore (mm) 23 Stroke (mm) 19.6 Output (Hp/r.p.m) 1.5 - 12500 Practical Range (r.p.m) 2500-12500 Prop Size 11x6 Weight (oz.) 16.61 Crankshaft 1/4x28 I bought all of my SK-50 engines from ats, who deals with Kangke USA. And broke them in like the SK thread recomemded.. I am currently trying a locally available (Cheap) 13-6 wooden prop, I normally use the 12-5 APC. MY engine's are different from the one Turk1 describes. My head gasket is copper only ,(one gasket only) not several gaskets. The exhaustports are also different. My carb does not bind. The U.S. distributor Kangke has aparently adressed the issues. Dont do what Xjet did. Quote RE: SK ENGINES - 9/23/2007 9:43:55 PM XJet Posts: 2511 Joined: 3/31/2003 From: Tokoroa, NEW ZEALAND Status: offline My SK50 didn't come with any instructions -- I bought it out of China rather than from the USA (saving a few bucks in the process) but I did read the online ones before firing up the engine. To me it sounds like Xjet bought sweepings (rejects from the factory floor often sold for parts only). If you buy one and have any trouble Call Kangke. The price is what attracted me. The slow break in is tolerable. My most broken in engine is sweet. The others are getting there. Use a test stand to break in. Sk 50 $60.00 + $9.00 shipping. |
RE: Anyone Flying SK engines?
I have 3 SK 50 s and one SK 80 ringed.No trouble at all.Very easy starting,reliable(if adjustments are OK: then deadly reliable on air).
My engines have more than one head gaskets and since I am using self mix,no nitro,full castor fuel,then I removed all except one for seal. Be careful not to adjust lean low speed needle before full break in finish. |
RE: Anyone Flying SK engines?
ORIGINAL: spad4mebaby Dont do what Xjet did. To me it sounds like Xjet bought sweepings (rejects from the factory floor often sold for parts only). What I've seen smacks far more of typically poor Chinese quality control and highly variable manufacturing tolerances. I bought a $7,000 Chinese lathe a month or so ago and despite the inspection book showing that all the alignment was near-perfect it took a couple of days to actually get things to the point where it could be used. One only has to look at the tales of woe that have accompanied the waves of cheap Chinese gas engines arriving on the market to see that way too many of these manufacturers don't give a hoot about quality control. I suspect that Kange my well be tossing out the *really* bad ones which is the level of QC the factory ought to be doing. The problem is that regularly checking and maintaining the tooling on which you make your engines costs money and if you're retailing an engine for $50 in the USA, that's an expense that some factories simply can't afford. The fact that my 50 was so very, very tight that even after heating the head with a torch, it almost self-destructed on the first tank of fuel indicates to me that the piston was actually oversized or that the bore was undersized at TDC. This is typical of manufacturing machinery wearing out of tolerance and nobody checking what's coming off the assembly line. The fact that they claim the SK ABC engines take "hours" to break in is another clue to the fact that they're expecting a wide variance in machining tolerances. No ABC engine should take more than two or three tanks of fuel to be broken in. I've had OS, TT, GMS, ST and a range of other engines that use ABC/ABN construction and they were all running very sweet and developing their maximum power within that time. I've bought Chinese-made engines (gaser) that were so badly assembled that they wouldn't even turn over because the bearings were pressed in crooked. Others have been so badly made that the piston smashed the factory-supplied spark-plug first time they were flipped over. *THIS* is the level of QC you often get from China and it's a factor that must be considered when making a purchase. I knew that buying an SK engine direct from China was a crap-shoot. I scored well with the 90 but lost on the 50. As a matter of interest -- where did Charlie P. get his SK? Did he also purchase direct from China? I'm sure that others have had as good results with the 50 as I've had with the 90 -- but (since I can only go on the basis of the engine I bought), I can't really recommend the 50 as a "good deal" in market where there is so much competition and most of that competition is clearly made to higher standards. For only a small amount of extra money you can get *much* better-made engines so why take the risk. Sure, Kange stand behind their product and will replace any that prove defective -- but what if it costs you a plane (as my 50 did)? Will Kange replace the plane and how will you feel about saving $20 when you've got $100+ worth of scrap balsa at your feet? (Waits for Sk50 fanboys to fire up their keyboards... :-) |
RE: Anyone Flying SK engines?
I agree with spad4mebaby and Ed Moorman.
I have two SK-50's both run great. On APC 12/5 with 15% wildcat they both turn 12,000+ static. There are at least 15 more flying locally with more on the way. XJet had problems right from the start, his engine is not a good baseline. The biggest problem I see with Kangke is Ray Nano has left the company and I don't know who they have doing support. I hope they keep it together, they're a good buy. |
RE: Anyone Flying SK engines?
If Kange want to send me one of their SK50s to test, I'll gladly video every step of the process and post for all to see, along with RPM figures etc.
Perhaps their SKs are ported differently and have a higher level of QC than those straight out of China. I just love that SK90 though and have already ordered another. |
RE: Anyone Flying SK engines?
I've been flying the SK50 and have so far been pleased with the performance.
It has been reliable and has enough power to fly the Phoenix SeaBee pattern type plane it is on. No dead sticks except when I run it out of fuel. 80$ plane and 50$ engine and my current favorite knock around plane. It will usually start with a backflip of the spinner. It turns the 11/7.5 or a 12/5 props well enough. I'd like a lighter engine with more power for my 50$.:D;) |
RE: Anyone Flying SK engines?
I fly a SK 40 and it's a good engine.
I broke it in flying without any problems. We have SK 40, 50, 90 and 130 here in Sweden. |
RE: Anyone Flying SK engines?
Yoo Hoo Xjet
If (Where-ever you are getting your engines) want to send me one of their SK90s to test, I'll gladly video every step of the process and post for all to see, along with RPM figures etc. I just love that SK90 though and have decided to try one. I promise a home made test stand just waiting for a try.. I promise to use the correct size of prop. I promise to use the correct fuel to oil mix. I promise not to overwind the engine. I will correctly adjust the carb. X jet are you saying you can do an un-biased assesment of an engine , maybe you should extend your offer to the makers of TT. |
RE: Anyone Flying SK engines?
I don't own one of these engines, but I've been keeping up with the posts on the SK .50's.
There are two camps: Those who broke them in following the factory instructions, are turning a 12x5 prop and love them. Those who didn't follow the factory instructions, are turning an 11x6 or smaller prop and think the engines are so-so. These are just a couple of facts that I've observed. If I ever buy one I know exactly what I will do. David |
RE: Anyone Flying SK engines?
Thanks guys - like every engine brand out there, some are great, some are not as great. I've had (like almost every 10+ years modeler) almost of the major engine brands. Some better than others. I'm looking ahead at my next couple of planes (a Older TF Red Box P-40 and hopefully the new VQ 40 size Hurricane). I love my 4S engines (Saito, OS, and Magnum). My OS 70 is a great running engine (but the threads for the exhaust pipe have stripped out), my Saito .65 is a honey, and I have two Magnums - .90 that finally broke-in and a .80 (bought with a plane)that I have to break-in. I thought I wasted my money on the Magnum 90 4S, but it gets a little better each flight (maybe 1 gal of fuel through it). From the feedback - I might just go ahead and order a .90 and think about maybe the .70 . We'll see how the money is after Christmas. (Club dues and AMA are always my present!)
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RE: Anyone Flying SK engines?
ORIGINAL: spad4mebaby Yoo Hoo Xjet If (Where-ever you are getting your engines) want to send me one of their SK90s to test, I'll gladly video every step of the process and post for all to see, along with RPM figures etc. I just love that SK90 though and have decided to try one. I promise a home made test stand just waiting for a try.. I promise to use the correct size of prop. I promise to use the correct fuel to oil mix. I promise not to overwind the engine. I will correctly adjust the carb. X jet are you saying you can do an un-biased assesment of an engine , maybe you should extend your offer to the makers of TT. |
RE: Anyone Flying SK engines?
ORIGINAL: rainedave I don't own one of these engines, but I've been keeping up with the posts on the SK .50's. There are two camps: Those who broke them in following the factory instructions, are turning a 12x5 prop and love them. Those who didn't follow the factory instructions, are turning an 11x6 or smaller prop and think the engines are so-so. These are just a couple of facts that I've observed. If I ever buy one I know exactly what I will do. David This is why places like RCU are so good. - Before I tried my first SK out - I did a search and the results all warned me about the slow revving nature of these engines and the fact that they normally turn much larger diameter props. One thing I can say about X-Jet's comments. He lives in the same marketplace as I spend a lot of my time (Australia and New Zealand) and we do seem to get a very high proportion of dud models of just about everything there (engines, Radios, Servos - - )- maybe it is because we are a smaller market and the suppliers don't have enough strength to scream loudly enough. |
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