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CMP 50 size Zero Balanceing HELP !

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CMP 50 size Zero Balanceing HELP !

Old 09-13-2008, 10:55 PM
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ZERO-322
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Default CMP 50 size Zero Balanceing HELP !

OK this is probably the first time I have built a CMP pro ARF and I got to say for the most part it has been allot of fun , however I have not flown this plane yet and am not sure after reading the reviews on RC Universe were I am suppose to balance this thing , everyone says the CG is listed wrong , my dilema is the instructions say the CG is 95 to 105mm from the LE this is were my model wants to balance , without adding a ridiculous amount of weight , this is were the main spar is located , this is also exactly 30 % the overall wing width , I also weighed my model and it falls to the exact specs that the manufacture says it should weigh completed ,all of these things is what I was taught in therory is were it is suppose to balance , but everything I have read on here states that the CG is listed wrong and to move it up to around 80 to 85mm ,they have built and flown this plane So who's right ? what should I do ? any help would be greatly appreciated
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Old 09-21-2008, 09:38 PM
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infernorcteam
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Default RE: CMP 50 size Zero Balanceing HELP !

I just finished this plane last night and flew it this morning. With a .46FX and a tuned pipe under the belly, I had to add almost 8oz to the firewall just to get it even close to balancing at 110mm. The tuned pipe does not weigh that much. I think this plane is just naturally tail heavy. Its still a little tail heavy for a warbird but I managed to tame it this morning by limiting my elevator end points and adding a little more expo than normal. First takeoff, it went straight up. Added enough down trim to land and made the adjustments to the radio.

Second flight was a blast! With the .46FX, retracts, tuned pipe, and an APC 10X8 this thing really moves. I need to see what it weighs.

My suggestion is add some nose weight and use lots of expo on your first flight. Build up some good ground speed before you lift it up because the tail wants to drop. I think my elevator now only moves about 10mm.

Hope this helps. Its a fun airplane once you get it dialed in.

Brandon
Old 09-23-2008, 01:01 AM
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ZERO-322
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Default RE: CMP 50 size Zero Balanceing HELP !

Hey thanks for the input ! however I have a few questions I installed the weight about 11 ounces give or take a gram as far up as I could get it , on the top motor mount rail to be exact , I am getting it to balance at 90mm do you think in your opnion that it will do good at this balance point ? I am using a thunder tiger pro 46 with an 10 x 7 prop , just at 6.5 Lbs do you think I will have ample power ? or mabey try the OS 55 wich is the same size only a slight marginal diffrence in HP ?

Thanks for your help !
Old 09-28-2008, 02:27 PM
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Navyvet
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Default RE: CMP 50 size Zero Balanceing HELP !

I recently bought this plane too and I'm reading alot of negative reports about the cg. I'm building it now and I plan on putting everything as far forward as possible. What I still don't see is "What is the correct cg for this zero?" I am not going to put a pound of nose weight in a 40 size warbird.
Old 06-27-2009, 06:03 AM
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Default RE: CMP 50 size Zero Balanceing HELP !

LOOKING FOR HELP TOO........I GOT 1 OF THESE,PLANNED ON A .46 &PITTS,NOW IM THINKING .75 4 STROKE
Old 06-27-2009, 06:58 AM
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Default RE: CMP 50 size Zero Balanceing HELP !

I noticed you're balancing the airplane right side up...at least that is the way it appears in the photos.....a low wing airplane should be balanced upside down....this puts all the weight below the balance point...
Old 06-27-2009, 07:06 AM
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Default RE: CMP 50 size Zero Balanceing HELP !

OK,STILL LOOK LIKE 10-11 OZ AT LEAST,ANY IDEAS ?
Old 06-28-2009, 10:45 PM
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Default RE: CMP 50 size Zero Balanceing HELP !

Ok just an update I finished it and wound up balance is at 80 mm from the LE I added 8.5 Oz to the nose , and ran a Thunder Tiger pro 46 with an 11 X 6 APC prop , and i have to say SHE FLYS AWSOME !!!!!!
Old 06-29-2009, 02:21 PM
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jeffk464
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Default RE: CMP 50 size Zero Balanceing HELP !

ORIGINAL: ZERO-322

Hey thanks for the input ! however I have a few questions I installed the weight about 11 ounces give or take a gram as far up as I could get it , on the top motor mount rail to be exact , I am getting it to balance at 90mm do you think in your opnion that it will do good at this balance point ? I am using a thunder tiger pro 46 with an 10 x 7 prop , just at 6.5 Lbs do you think I will have ample power ? or mabey try the OS 55 wich is the same size only a slight marginal diffrence in HP ?

Thanks for your help !
I would definitely vote for the OS55 for this plane. Swings a bigger prop and is a higher torque engine, plus it doesn't have the high pitch whine. If you aren't worried about money I was thinking about buying one of these and tossing my OS91 FS in it, might be an interesting combo.
Old 06-29-2009, 02:24 PM
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Default RE: CMP 50 size Zero Balanceing HELP !


ORIGINAL: jetmech05

I noticed you're balancing the airplane right side up...at least that is the way it appears in the photos.....a low wing airplane should be balanced upside down....this puts all the weight below the balance point...
To add, the landing gear should also be out, not retracted.
Old 06-29-2009, 02:27 PM
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jeffk464
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Default RE: CMP 50 size Zero Balanceing HELP !


ORIGINAL: BUCKSHOTRC

LOOKING FOR HELP TOO........I GOT 1 OF THESE,PLANNED ON A .46 &PITTS,NOW IM THINKING .75 4 STROKE
Go for a OS91 4 stroke, you will just be adding more lead anyways with the .75.
Old 06-29-2009, 09:00 PM
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BUCKSHOTRC
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Default RE: CMP 50 size Zero Balanceing HELP !

9 OZ ON THE PITTS & STILL TAIL HEAVY ....I HAVE AN ENYA .90 4 STROKE..................
Old 06-29-2009, 09:32 PM
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jeffk464
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Default RE: CMP 50 size Zero Balanceing HELP !

ORIGINAL: BUCKSHOTRC

9 OZ ON THE PITTS & STILL TAIL HEAVY ....I HAVE AN ENYA .90 4 STROKE..................
Is your plane flying yet? I am really interested to know how it flies with this size 4 stroke.
Old 06-29-2009, 10:27 PM
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BUCKSHOTRC
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Default RE: CMP 50 size Zero Balanceing HELP !

NO...NOT UNTILL I GET PUT A 4 STROKE ON IT

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