[AR] Re: dynamic stability
- From: Bill Claybaugh <wclaybaugh2@xxxxxxxxxx>
- To: "arocket@xxxxxxxxxxxxx" <arocket@xxxxxxxxxxxxx>
- Date: Thu, 21 Aug 2014 10:43:40 -0600
Carl:
I believe FAA is looking for the 6DOF moments which are required inputs to any
dispersion analysis.
If your vehicle is fully axisymmetric the pitch and yaw moments should be the
same. However, that is rarely the case in the payload and any asymmetry will
induce coning unless balanced. This is why dynamic balancing is required on
all professional payloads.
If you are flying a liquid I would strongly recommend dynamic balancing the
entire vehicle (a very good practice even if you are flying a fully symmetric
solid--density variations in the propellant can influence stability). Static
stability testing is not sufficient.
Bill
Sent from my iPhone
On Aug 20, 2014, at 15:45, Carl Tedesco <ctedesco@xxxxxxxxxxxxxx> wrote:
> I am starting the process for getting a class 3 waiver for a rocket launch.
> Most of the FAA required documentation looks straight forward. One piece of
> information they require is "The dynamic stability characteristics for the
> entire flight profile." A static stability analysis is straight-forward, but
> I have never done a dynamic stability analysis.
>
> How have folks on this list addressed this requirement? Is this software
> driven analysis or just hand-calculations? Does anyone have an analysis they
> could share? If software analysis is the norm, can anyone point me to
> affordable software?
>
> --- Carl
>
> --
> Carl Tedesco
> Flometrics, Inc.
> 5900 Sea Lion Place, Suite 150
> Carlsbad, CA 92010
> tel: 760-476-2770 ext. 515
> fax: 760-476-2763
> ctedesco@xxxxxxxxxxxxxx
> www.flometrics.com
>
>
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