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-   -   The real story with CG (http://www.rcuniverse.com/forum/3d-flying-82/11221615-real-story-cg.html)

stevegauth30 09-08-2012 04:55 AM

The real story with CG
 
Ok, so, I've been flying rc for my whole life, but to 3d flying, I'm a newb. I've been getting conflicting answers as to CG. Some say you want an aft CG to perform a lot of maneuvers, and some say you want a balanced model. I'm sure there's a fine line , and a lot of it is opinion, but what's your thoughts on it. Thanks in advance for the knowledge.

ThumbSkull 09-08-2012 06:02 AM

RE: The real story with CG
 
A proper CG for 3D puts the plane upright and inverted flying level with no elevator input.
Most people think you need tail heavy but you don't, it just gets squirrely.
To most it's more tail heavy than they are used to when it's actually neutral.

stevegauth30 09-08-2012 06:18 AM

RE: The real story with CG
 
Thanks for your advice. But will it hang straight off the prop? Or will it want to pitch forward?

ThumbSkull 09-08-2012 06:38 AM

RE: The real story with CG
 
None will just 'hang' there, regardless of CG position. You have to fly it all the time making minor corrections.

Cobra1 09-11-2012 03:39 AM

RE: The real story with CG
 
With the CG at a point where inverted takes little to no down elevator input will just make the aircraft a better overall flyer. Any further aft does not make hanging on the prop any easier. That just take a lot of practice and pretty fast servos.

ahicks 09-11-2012 04:48 AM

RE: The real story with CG
 
I think they call it an aft CG because it's aft of the CG generally suggested by the manf? I agree once you find the neutral CG there's nothing to be gained by going further back, though there may be some special application for that I'm not aware of.

I would also caution a rookie flier regarding moving the CG back. The plane will loose a lot of it's forgiveness, depending instead on a pilot's flying ability to keep air under the plane? The plane will generally stall at a lower speed (maybe much slower!), but when it does stall, it will not recover by itself as easily, if at all. You may have to fly it out of the stall? Not a big deal for somebody who can fly, but maybe a bit challenging for those with less stick time. Low time or less experienced that want to play with CG should go a little at a time, testing each change as soon as possible by slowing the plane while 3 mistakes high and playing with the stall - so they know what to expect when it's time to land. Too many skip this step, figuring it's not necessary, until they are educated on short final....

Regarding which way it's going to fall, it can/will fall in any direction? Practicing down low can get expensive....

zacharyR 09-11-2012 05:54 AM

RE: The real story with CG
 
just use a sticky weight and move it around... GO FLY ... moral of the story

stevegauth30 09-11-2012 12:41 PM

RE: The real story with CG
 
I balanced the plane neutral and it flies perfectly. As far as the hovering, well I would agree that ot just takes a lot of practicing. I'm getting it though. Thanks for all of your input.

kerwin50 09-11-2012 11:43 PM

RE: The real story with CG
 
Every plane is different some planes like my little 3dhs edge like a more rearward cg. Then again my goldwing MX likes a neutral cg and will lock into a hover so easy it's amazing.
My flat foamie from west michgan parkflyers likes it really tail heavy and locks into a hover as well.

flyboy138 10-20-2012 07:38 PM

RE: The real story with CG
 
Thumbskull said it right None will just 'hang' there, regardless of CG position. You have to fly it all the time making minor corrections. And burn lots of fuel.


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