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CG of Delta Wing

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Old 05-02-2003, 01:16 PM
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tonstel
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Default CG of Delta Wing

I am looking for info on where the CG should be on a delta wing. Any help is appreciated.

Thanks
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Old 05-02-2003, 06:41 PM
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CrazyHerb-RCU-delete
 
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Default Get ya close...

Here's what usually gets me close...

A flying wing should be 17% or thereabouts...(square wing)

So, I just make it a right triangle and double the distance of what 17% would be if it were a square or rectangle. With the given 45 degree sweep...17% is 6.8 inches on your 40 inch chord ..
doubled gives you...
13.6 inches MINUS what you would have on the nose if it were a point...if 45 degrees... would be 2.5 inches or so...so subtract that from the 13.6 and you get about 11 inches from the nose...

Hope that helps....

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Old 05-02-2003, 07:09 PM
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ChrisSpad
 
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Default CG of Delta Wing

hmm. Here's how i do it:

Plug your figures into this calculator:

http://www.palosrc.com/instructors/cg.htm

Is this a flat wing, or an airfoiled plane? It does make a difference in the cg.

I wouldn't go any further than 17% mac, i usually start at 12-13%, and move it back, if necessary.

13% mac, is about 14 1/8" behind the lleading edge at the root, and 17% mac is 15 3/8" behind the leading edge, at the root.
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Old 05-02-2003, 08:12 PM
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tonstel
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Default CG of Delta Wing

You guys are awesome! Thanks, will post pictures when it is done.

Thanks again...
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Old 05-04-2003, 08:22 PM
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tonstel
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Default CG of Delta Wing

Another question on delta type planes balance. It just seem that the balance should be back further. (Yes I am having a balance issue). Got it a little tail heavy. Without additng weight and the gear mounted as forward as possible it is still too tail heavy. Was thinking of getting a larger fuel tank, maybe 14oz. I would never run out of fuel for sure. I have a O.S. 65LA I am putting on. Yes I thought of putting a larger engine on but that is not possible at this time.

Any ideas appreciated......
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Old 05-04-2003, 10:40 PM
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I would add lead to the nose, and fly it to see what it needs to do. Most of it might have to come off anyway. The other option is to extend the motor mount forward some to compensate for the tail heavy condition.
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Old 05-05-2003, 01:21 AM
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tonstel
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Default CG of Delta Wing

I will try moving the engine, thanks for the help ChrisSpad...
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