stunthanger.com
Engine basics => Engine set up tips => Topic started by: Matt Curtis on April 24, 2018, 07:15:11 PM
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Has anyone been running a K&B sportster .28 Are you able to run it stock with the venturi and nva assembly that it comes with? Mine is not running well in stock form. I think the venturi is way too big? I did get a good answer about this on Stuka stunt but wondering if there are other answers as well since I only got 1 reply.
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I will post again if I get this engine to run well. I am hoping it will work as the os la .25 and fp .25 are getting hard to find and at some point there won't be any left to buy. If this happens it will be hard to fly a ringmaster if you can't buy .25 to .28 size engines?
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Measure the venturi diameter with a calipers or even by just trying drills of different size to estimate it. For C/L sport flying it should be under about .285 with the typical OS or Super tigre style needle valves. If the motor can't be adjusted to run rich with the nose pointing straight up the venturi is too big, or there are leaks in the the fuel system somewhere.
I had several K&B 28's. They ran just fine although many of them a needed a long break in. The aluminum sleeve and iron coated piston don't wear as as fast as iron on steel or aluminum on chrome.
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I will post again if I get this engine to run well. I am hoping it will work as the os la .25 and fp .25 are getting hard to find and at some point there won't be any left to buy. If this happens it will be hard to fly a ringmaster if you can't buy .25 to .28 size engines?
A good modern 15 may work well in a light Ringmaster. Certainly mine had more than enough power with a 20FP.
Or just cave to the fact that the world is going 'lectric, and make an electric Ringmaster.