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12-14-2009, 05:58 PM | #1 |
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CG Again
OK I know its been asked a dozen times and will probably be asked that at least again. How do I get the CG on my Bipe. Plans are almost non-existent and there is no where it shows CG. Talks about it (where to have the battery)changing CG but thats it. It has a straight wing on the bottom and a swept back one on the top. If memory serves right it is balanced up side down. Will try and get a picture of it on here Thanks in advance
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12-14-2009, 06:19 PM | #2 |
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Re: CG Again
You balance a Bipe upright by the top wing.
Measure the full chord of both wings. Do this by looking down at the plane from above. Measure from the leading edge of the top wing to the trailing edge of the lower wing. Once you have that measurement divide it by 4 to get 25% of what you measured. That is the distance you measure back from the leading edge of the top wing. That will get you in the ball park. You can fine tune from there. Never pay again for live sex! | Hot girls doing naughty stuff for free! | Chat for free!
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12-14-2009, 06:37 PM | #3 |
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Re: CG Again
just put the battery in the most forward position recomended and go from there ,be sure to use a battery in the proper weight range ,all bipes have a differant wing stagger & sweep so all are differant.what I have done in the past is measure from the leading edge of the top wing to the trailing edge of the lower wing and make a mark 25% of the total distance from the leading edge of the top wing .it's not perfect but it's worked so far for me.Roger
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12-14-2009, 07:29 PM | #4 |
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Re: CG Again
Give this calculator a try. I've used it, and compared it with the manual, and everything flew OK.
http://adamone.rchomepage.com/ Daren
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12-15-2009, 08:20 AM | #5 |
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Re: CG Again
The "Mean Aerodynamic Chord" (MAC) has to be established. It is along this line that the % of the chord measurement from the leading edge is made.
Use this diagram. Looking directly from above both wings treat the combined outline as one wing planform. Ed s |
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12-15-2009, 08:39 AM | #6 | |
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Re: CG Again
Quote:
You need to do this when you have 2 different wing geometries Find the Mean Aerodynamic Cord of the top wing Find the Mean Aerodynamic Chord of the bottom wing, and divide the distance between them by 2. That should be close. Purists will tell you that you will also need to factor the distance between each wing and the centerline of the fuselage axis (which is usually, but not always, the centerlune of the the thrust axis) but lets just skip that for now.. |
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