Quantcast

CG Sticker placement

The Rocketry Forum

Help Support The Rocketry Forum:

Faroutspacenut

Member
TRF Supporter
Joined
Feb 22, 2017
Messages
178
Reaction score
12
Hi Everyone, I'm putting the finishing touches on my first serious mid-power rocket and got some of those cool little CP/CG stickers. The CP sticker will obviously go where my sims tell me to put it, but I'm wondering about marking the center of gravity. I'm realizing that its kind of pointless (apart from looking cool) because the CG is going to change depending on what motor I use. So now I'm wondering what the best practice for using these indicators is? Mark the CG without the motor? move and re-apply every time you change motors? not even bother with the CG sticker?

rob
 

Nytrunner

Pop lugs, not drugs
TRF Supporter
Joined
Oct 15, 2016
Messages
7,756
Reaction score
3,383
Location
Huntsville AL
I'd put it at the location for the motor that you will fly the most.
 

Faroutspacenut

Member
TRF Supporter
Joined
Feb 22, 2017
Messages
178
Reaction score
12
Good suggestion, thanks. I'm planning on trying out a few different motors anyway.
 

OverTheTop

Well-Known Member
TRF Supporter
Joined
Jul 10, 2007
Messages
4,866
Reaction score
2,118
Location
Melbourne Australia
I just put CP stickers as the CG wafts around a bit depending on motors and everything else. I check balance just before going to the RSO.

If you do fit it it may give you confidence in static stability where skepticism is perhaps warranted.
 

Steve Shannon

Well-Known Member
TRF Supporter
Joined
Jul 23, 2011
Messages
6,608
Reaction score
3,427
Location
Butte, Montana
You could place the Cg sticker one caliber ahead of the Cp sticker (or whatever margin you prefer) and then write the words "Aftmost Limit" next to it. As long as your actual Cg falls forward of that limit you should be stable.
 

MCriscione

Well-Known Member
Joined
Jul 9, 2015
Messages
296
Reaction score
0
You could place the Cg sticker one caliber ahead of the Cp sticker (or whatever margin you prefer) and then write the words "Aftmost Limit" next to it. As long as your actual Cg falls forward of that limit you should be stable.
+1 I like to put it at the 1 cal mark, or whatever you feel comfortable with as a minimum to fly safely. Thus if my actual CG is ahead of it, I know I'm good to fly. Also, easy to show the RSO.

I suppose for a short, squat rocket, that might be less than 1 cal.
 

Flyfalcons

Well-Known Member
Joined
Apr 14, 2015
Messages
2,488
Reaction score
659
You could place the Cg sticker one caliber ahead of the Cp sticker (or whatever margin you prefer) and then write the words "Aftmost Limit" next to it. As long as your actual Cg falls forward of that limit you should be stable.
When I mark CG, this is generally what I do.
 

Bat-mite

Rocketeer in MD
Joined
Dec 5, 2013
Messages
10,986
Reaction score
1,738
Location
Maryland
+1 I like to put it at the 1 cal mark, or whatever you feel comfortable with as a minimum to fly safely. Thus if my actual CG is ahead of it, I know I'm good to fly. Also, easy to show the RSO.

I suppose for a short, squat rocket, that might be less than 1 cal.
Bingo!
 
Top