CG location - RC Groups
May 30, 2011, 05:41 PM
Registered User
Discussion

# CG location

I'm putting together a old JR glasscraft predator. Does anyone know what the CG is.
Thanks,
Dale
 May 30, 2011, 05:44 PM Crikey never leave beer behind Go 28 % of the root chord and go from there pretty much the average on most conventional slopers
May 30, 2011, 05:51 PM
AMA 105167
Quote:
 Originally Posted by steve wenban Go 28 % of the root chord and go from there pretty much the average on most conventional slopers
I Concur ... 25% (on the Nose heavy side) to 30% (approaching neutral) will get you in the air (safely, without too many headaches as a rule of thumb) ...
 May 30, 2011, 05:54 PM Registered User Ok for a 8 1/2" root chord, CG should be around 2 3/8" from the leading edge. Correct?
May 30, 2011, 05:58 PM
AMA 105167
Quote:
 Originally Posted by old sloper Ok for a 8 1/2" root chord, CG should be around 2 3/8" from the leading edge. Correct?
Yes.

2.375/8.5 = 0.279 .... or 27.9%
 May 30, 2011, 06:00 PM AMA 105167 But ... I would go 28% on the MAC .... this is only if you do not have a constant cord, non- swept wing ... If you have a sweept wing or a tip cord of a different size ... then you need to calculate from the mean aerodynamic cord ...
 May 30, 2011, 06:02 PM Crikey never leave beer behind 2.776" yep close enough for rock and roll
 May 30, 2011, 06:07 PM Crikey never leave beer behind or measure the root divide by 3 and come forward a 1/4 "
 May 30, 2011, 06:26 PM Registered User Thanks alot you guys. That will get me in the air. I knew i could count on you. Dale
 May 30, 2011, 06:31 PM AMA 105167 or ... if this gets too crazy ... there is always this: Aircraft Center of Gravity Calculator
 May 30, 2011, 06:32 PM Crikey never leave beer behind Actually when I think about it I've got a kit under my bench I'll dig it out and do what men dont do and read the instructions SHHHHH!!!!! dont tell though ok
May 30, 2011, 06:48 PM
AMA 105167
Quote:
 Originally Posted by steve wenban Actually when I think about it I've got a kit under my bench I'll dig it out and do what men dont do and read the instructions SHHHHH!!!!! dont tell though ok
Mate! that's sacrilege!

Totally against the rules dictated in the "Man BOOK" ...

Written right there on page 123, section 123, article 1.2.3.a" No MAN shall EVER Ask for directions or EVER refer to reading an INSTRUCTION Manual until thoroughly lost, confused or exhausted all other failing attempts prior to such unmanly practices"
 May 30, 2011, 06:54 PM Crikey never leave beer behind I blame the GPS alllllll the time
May 30, 2011, 07:06 PM
AMA 105167
Quote:
 Originally Posted by steve wenban I blame the GPS alllllll the time
GPS!

Real Men use MAPS ... Folded out in front of ther face while driving!

ROTFLMAO!
 May 30, 2011, 07:09 PM Crikey never leave beer behind a Map ???? I dont use a Map I say I'm going there and I go and I dont listen to the GPS cause that girl lies to ya take the next exit or as soon as posssible perform a uturn when safe pffft yeah right