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Old Aug 25, 2014, 08:23 PM
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United States, CA, Redlands
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Originally Posted by MAMBA2200 View Post
Man I have 13 oz on nose and the tail is still on ground bout to give up
Are you sure you're balancing it properly? Can you post a picture of it? I'm assuming you haven't tried to fly the plane yet, have you?
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Old Aug 25, 2014, 08:33 PM
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United States, TN, Dandridge
Joined Mar 2013
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Yes upside down on 90mm but if you go one third which is about 115mm its absolutley perfect with no weight and im using my cg machine and no I have not tried to fly till I get a definitive answer on this dont wanna lose 400 bucks for not being thorough and I am doing this one just like all my other planes
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Old Aug 25, 2014, 08:58 PM
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United States, AR, Cabot
Joined Oct 2007
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Frankly, it takes a severely aft CG before the plane is unflyable. I would use this pic as a reference, and eyeball it. Every plane is a bit unique. CG numbers don't mean squat to me. Basically, thickest portion of the wing, and aft of the retract, and you will be golden. If you don't stay behind the retract, it will nose over. Even still, it really needs full up elevator when taxiing. Especially on grass.

-CC
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Old Aug 25, 2014, 09:05 PM
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Ok will try this for sure thanks cub man im going crazy trying to figure this one out
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Old Aug 25, 2014, 09:08 PM
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I just looked and that is at 115mm where I have found that it balances perfect with no weight added
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Old Aug 25, 2014, 09:22 PM
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If you look at where the manual says 90mm is its really not cause its dead between the 2 lines on the wing and if you measure that out between the 2 lines its 115mm think im gonna go with what you say cubcrazy and say forget the numbers and go with logic the 1700p51 balances at 120mm it makes sense that this plane would be closer to that number 90 sounds like a balance point for my 1400mm jug
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Old Aug 25, 2014, 09:51 PM
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Yes, up elevator when taxiing! If it looks like it's going to nose over while taxiing be sure to kill the throttle. I'm sure the speed control on my Mustang crapped the bed because of that.

I second Cubcrazy on the CG issue. Have fun!
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Old Aug 26, 2014, 03:18 AM
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United States, IL, Cypress
Joined Sep 2013
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Quote:
Originally Posted by MAMBA2200 View Post
If you look at where the manual says 90mm is its really not cause its dead between the 2 lines on the wing and if you measure that out between the 2 lines its 115mm think im gonna go with what you say cubcrazy and say forget the numbers and go with logic the 1700p51 balances at 120mm it makes sense that this plane would be closer to that number 90 sounds like a balance point for my 1400mm jug
I sent you a reply on the motionrc forum. But I had the same exact problem with the one I just bought. I did put some weight in the nose, but that is because I added speakers mainly. The 90mm CG imo is not correct. I used a great planes cg machine and I was laying all kinds of lead in it and that tail was still not wanting to come up. I said screw it, installed the sound system, added very little weight to the nose, I am thinking maybe an ounce or 3/4, I did that just to make up for a couple speakers on the wrong side of CG. I finger tip checked it this time I went by the manual pictures and yeah that is the thick spot, and it was just slightly nose heavy with a 4000mah battery so I lived with it. It flew great.
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Old Aug 26, 2014, 05:15 AM
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United States, GA, Rincon
Joined May 2011
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Quote:
Originally Posted by MAMBA2200 View Post
If you look at where the manual says 90mm is its really not cause its dead between the 2 lines on the wing and if you measure that out between the 2 lines its 115mm think im gonna go with what you say cubcrazy and say forget the numbers and go with logic the 1700p51 balances at 120mm it makes sense that this plane would be closer to that number 90 sounds like a balance point for my 1400mm jug
Mamba, stop driving yourself nuts about this. I too went the same route with my first 1700 mm Bunny and added weight using the 90 mm cg point. Result: nose over landing, one after another. It came in too hot no matter what with the result of many a bent struts. Now on my second P-47, I followed Michie's lead and said the heck with the 90, it's totally bogus IMHO. Used the pictures he posted and it worked out to be 100 mm for cg. Result: lands like a kitten and flies far superior.
BTW I was using a GensAce 5500 6 cell because everyone on the thread early on was saying that you need a 5000 6 cell to get it to balance using 90 mm cg so I figured why not use it in extra battery capacity and have longer flight times. WRONG.

Hope this helps,

Alec

http://www.rcgroups.com/forums/showp...postcount=2119
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Last edited by Motrolflyer; Aug 26, 2014 at 05:22 AM.
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Old Aug 26, 2014, 07:11 AM
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Thanks allot guys i feel better about what i have now and think it will be ok thanks for all the input it is greatly appreciated
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