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  • November 28, 2020, 01:41:25 AM

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Author Topic: nose moment mod for 4 stroke engine?  (Read 206 times)

Offline Charles Hofacker

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nose moment mod for 4 stroke engine?
« on: June 24, 2020, 12:29:12 PM »
Hi All.
I'm looking at converting an R/C 4 stroke engine for c/l. At a minimum this will require a c/l style venturi to replace the throttle carb. But here's the question. Since the engine is wider than the 2" standard I will be modifying the fuselage as necessary I think I might as well address the greater weight of the engine and the nose moment. The engine weighs 20oz. with muffler. The airplane is Bob Whitley's Shoestring 2000.  I can calculate the new nose moment arm if you can give me engine weights preferably with muffler. Or if you've already worked out the problem and can give me suggestions for nose length, I'd sure appreciate that too. Even if you have no direct experience with this exact mod p[ease help me out with suggestions.
Thanks!
CRH


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Offline Charles Hofacker

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Re: nose moment mod for 4 stroke engine?
« Reply #1 on: June 25, 2020, 08:46:51 AM »
Does anyone know what engine was on Mr. Whitley's Shoestring 2000?

Offline Ted Fancher

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Re: nose moment mod for 4 stroke engine?
« Reply #2 on: July 12, 2020, 04:49:25 PM »
Charles,

Ask the question re Bob's Shoestring engine on the "Open" (the main) forum and you'll likely get a lot more responses.  These downline threads can sometimes lie dormant for some time.

Once you've got the weight of Bob's engine measure from the Shoestring plan's center of gravity to ~the front hold down bolt in inches (a rough approximation of the CG of the engine). Multiply that distance by the weight of the Bob's engine in ounces and get a result in "oz/inches".  Then divide that number by the weight of your four stroke and the result will give you a reasonably practical location for the front hold down bolts on the four stroke.

By the way, 19oz sounds like a pretty big engine for one of Bob's "usual" ships although I'm not an expert on four strokes. You'll likely come out with a much shorter nose after doing the math and then might have an issue with tank length....Just a thought.

Ted Fancher


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