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All Forums >> Glow Engines, Gas Engines, Fuel & Mfg Support Forums >> Glow Engines >> RE: SK ENGINES
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RE: SK ENGINES - 7/15/2008 7:32:57 AM   
gaboooka


 

Posts: 17
Joined: 6/16/2006
From: Gyongyos, HUNGARY
Status: offline 		The test motor in the review not lighter.
But the SK 130 0.6HP stronger in same weight. I buy a 17x6 wood prop for test.
The pitts style muffler how many power drop?

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       Post #: 526

RE: SK ENGINES - 7/15/2008 10:12:43 AM   
Turk1



Posts: 635
Joined: 10/8/2004
From: Istanbul, TURKEY
Status: online 		Hi, on a SK 90, what is your RPM s and with which prop and fuel??

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       Post #: 527

RE: SK ENGINES - 7/19/2008 2:20:25 AM   
prgonzalez



Posts: 337
Joined: 6/7/2004
From: KATY, TX, USA
Status: offline 		Here I come with a new one. My SK-90 is having this RPM curve. (I hope the chart can be seen correctly).

I have tried with and without cline regulator and with and without uniflow. I have tried PM 5% and 10% nitro with 18% oil castor blend. APC 15x6 prop. It is always the same problem. While in flight, if I happen to hit the stick in the dead spot and go into a loop, I have dead stick. Any ideas?

The X-axis is carb opening and Y-axis is RPMs.

Pedro


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< Message edited by prgonzalez -- 7/19/2008 3:06:34 AM >

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       Post #: 528

RE: SK ENGINES - 7/19/2008 2:26:59 AM   
XJet


 

Posts: 3354
Joined: 3/31/2003
From: Tokoroa, NEW ZEALAND
Status: offline 		What size prop are you running? What is PW 5%?

How much nitro are you running?

< Message edited by XJet -- 7/19/2008 2:27:15 AM >

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       Post #: 529

RE: SK ENGINES - 7/19/2008 2:43:23 AM   
Ed_Moorman



Posts: 3678
Joined: 1/5/2002
From: Shalimar, FL, USA
Status: offline 		Believe what you want, I was told by the engineer that the 90 has a tapered bore and you should never run it rich. You do what you want. I have 2 that run great as does my 50.

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       Post #: 530

RE: SK ENGINES - 7/19/2008 3:04:20 AM   
prgonzalez



Posts: 337
Joined: 6/7/2004
From: KATY, TX, USA
Status: offline 		Ooops...the fuel is Power Master, PM not PW. Big typo, isn't it?

I have used 5% and 10% nitro with 18% oil castor blend. Prop is APC 15x6 as recommended by Kangke. Max RPMs are 9500, then I back down to 9300.

Do you guys think something is wrong in the LSN shape?

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       Post #: 531

RE: SK ENGINES - 7/19/2008 4:18:52 AM   
XJet


 

Posts: 3354
Joined: 3/31/2003
From: Tokoroa, NEW ZEALAND
Status: offline
quote:

ORIGINAL: Ed_Moorman

Believe what you want, I was told by the engineer that the 90 has a tapered bore and you should never run it rich. You do what you want. I have 2 that run great as does my 50.

Who is "the engineer"? Is this the guy who designed the engine or just "an engineer" who works for the distributor?

If I ever have to strip my SK90 I'll mic the bore and find out for sure.

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       Post #: 532

RE: SK ENGINES - 7/19/2008 5:02:01 AM   
Turk1



Posts: 635
Joined: 10/8/2004
From: Istanbul, TURKEY
Status: online 		A friend of mine has newly put his SK 90(2 years old but brand new) on his Mustang and he read 10400 max.with 10 % nitro fuel.prop was 15-6.

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       Post #: 533

RE: SK ENGINES - 7/19/2008 5:22:54 AM   
XJet


 

Posts: 3354
Joined: 3/31/2003
From: Tokoroa, NEW ZEALAND
Status: offline 		Turk, he'd probably find it flew a lot nicer with a 14x8 if it's a .60-.90 sized Mustang. At 10K RPMs you're only getting a propwash speed of around 55mph so the flying speed (straight and level) will only be 50mph (80Kph) or so. Moving up to an 14x8 prop will increase the flying speed by around 25% or so.

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       Post #: 534

RE: SK ENGINES - 7/19/2008 7:42:40 PM   
prgonzalez



Posts: 337
Joined: 6/7/2004
From: KATY, TX, USA
Status: offline 		Boy...I am happy but dissapointed at the same time. I found the problem with my SK RPM issue with the flat spot right before WOT.

It is definetely the carb. I did the opposite of what Ed Moorman did with his TH75 and SK-90 carbs. I installed my TH-75 carb in my SK-90. The flat spot is gone and the engine is tunning like a dream.

So, !#$%#$ SK carb. Well, at least I know the engine is good and I know what the solution is. Now I need a new carb for my TH75 and there are no parts .


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       Post #: 535

RE: SK ENGINES - 7/19/2008 8:11:17 PM   
rainedave



Posts: 5028
Joined: 7/21/2005
From: Greensboro, NC, USA
Status: offline 		A Perry 1501 will fit the Tower Hobbies .61/.75 engines.

David

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       Post #: 536

RE: SK ENGINES - 7/19/2008 9:54:39 PM   
XJet


 

Posts: 3354
Joined: 3/31/2003
From: Tokoroa, NEW ZEALAND
Status: offline 		Yep, the SK engines use a carby that's been around for donkey's years within the Chinese-made engine industry.

It's pretty simple, has "average" fuel metering and there's not actually that much wrong with it. Perhaps yours is a bad example because my SK90 has no flat-spot at all or perhaps you've under/over-propped yours.

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       Post #: 537

RE: SK ENGINES - 7/19/2008 10:52:26 PM   
prgonzalez



Posts: 337
Joined: 6/7/2004
From: KATY, TX, USA
Status: offline 		Xjet,

My guess is the carb that came with it is a bad example. I had problems with that carb since brand new.

If I understand you correctly, what you are saying about the over/under prop is the flat-spot would be present with one particular carb and not with another?


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       Post #: 538

RE: SK ENGINES - 7/19/2008 10:59:58 PM   
prgonzalez



Posts: 337
Joined: 6/7/2004
From: KATY, TX, USA
Status: offline 		Dave,

The perry carb has similar price as the TH carb w/remote needle. Aren't perry carbs designed for their pumps?

(in reply to rainedave)
       Post #: 539

RE: SK ENGINES - 7/19/2008 11:59:17 PM