LOC Onyx CP/CG

LOC Onyx CP/CG

Post by Wil Ladewi » Thu, 19 Jun 1997 04:00:00



I'm preparing to launch the Onyx at ROCSTOCK V.  I did the CP/CG calc, and
found that the CG need to be moved forward approx. 3 inches to a point
15.55 inches from the tip. This required the addition of allot of ballast
(modeling clay) weight. The plan is to fly the Onyx on a G75 reload. Can
anybody tell me if I really need to add the ballast weight, or is the "out
of the kit" design aerodynamically stable as is?

 
 
 

LOC Onyx CP/CG

Post by Leonard T. Bolton II » Sat, 21 Jun 1997 04:00:00




Quote:
> I'm preparing to launch the Onyx at ROCSTOCK V.  I did the CP/CG calc,
and
> found that the CG need to be moved forward approx. 3 inches to a point
> 15.55 inches from the tip. This required the addition of allot of ballast
> (modeling clay) weight. The plan is to fly the Onyx on a G75 reload. Can
> anybody tell me if I really need to add the ballast weight, or is the
"out
> of the kit" design aerodynamically stable as is?

My Onyx was built as per the instructions with no ballast.  Flown with G40
throw-aways and several F reloads.  It proved to me to be very stable.

 
 
 

LOC Onyx CP/CG

Post by john bolen » Sat, 21 Jun 1997 04:00:00



Quote:



> > I'm preparing to launch the Onyx at ROCSTOCK V.  I did the CP/CG calc,
> and
> > found that the CG need to be moved forward approx. 3 inches to a point
> > 15.55 inches from the tip. This required the addition of allot of ballast
> > (modeling clay) weight. The plan is to fly the Onyx on a G75 reload. Can
> > anybody tell me if I really need to add the ballast weight, or is the
> "out
> > of the kit" design aerodynamically stable as is?

> My Onyx was built as per the instructions with no ballast.  Flown with G40
> throw-aways and several F reloads.  It proved to me to be very stable.

I added 2 ounces of nose weight so that I could use G64 and H128 motors.
--
John Bolene
OKC Tripoli Secretary, newsletter editor, and webmaster
Sooner Boomer 14 High Power rocket launch, June 28-29, Medford Oklahoma
OKC Tripoli Web page -> http://www.flash.net/~jbolene/okc-trip.htm
Get the r.m.r. FAQ at: http://dtm-corp.com/~sven/rockets/rmrfaq.toc.html
 
 
 

LOC Onyx CP/CG

Post by Bob Kapl » Sat, 21 Jun 1997 04:00:00


Quote:

> I'm preparing to launch the Onyx at ROCSTOCK V.  I did the CP/CG calc, and
> found that the CG need to be moved forward approx. 3 inches to a point
> 15.55 inches from the tip. This required the addition of allot of ballast
> (modeling clay) weight. The plan is to fly the Onyx on a G75 reload. Can
> anybody tell me if I really need to add the ballast weight, or is the "out
> of the kit" design aerodynamically stable as is?

My 7 year old table (that I've posted here at least twice before) has the
Onyx CP at 18.33" from the nose tip or 1.166 forward of the fin leading
edge. SOunds like we're in pretty close agreement.

With a G75, you probably need the weight. I'm sure this motor isn't on LOCs
"recommended" list for this rocket, as he doesn't recommend any reloads for
his kits. Of course, that doesn't mean that it won't work, if you add enough
nose weight to preserve stability. Try balancing it with an F50, and keep
the CG inthe same place.

        Bob Kaplow      NAR # 18L       TRA # "Abort, Retry, Fail?"