Re: Re: F1D partial motor blast shield

From: William Gowen <wdgowen_at_gmail.com>
Date: Thu, 19 Jul 2012 19:08:44 -0400

Just wrap the motor tube with graphene.

On 7/19/2012 7:04 PM, Yuan Kang Lee wrote:
>
> Assuming that you place the extra balsa where the partial motor is, it
> will be impossible to replicate the same CG as the full motor. It
> would be 50 mg of weight placed well in front of the CG. Perhaps the
> effect is small.
>
> The other question I have is how much protection does the extra balsa
> provide. If the protection is adequate, does this mean that extra
> balsa over the full length of the motor stick (100 mg of balsa) could
> protect the whole motor stick? It would be nice if this is the case,
> but it would be difficult to find a spare 100 mg. If you could spare
> 50 mg and protect part of the stick from an exploding full motor,
> where would you place the protection?
>
> --- In Indoor_Construction_at_yahoogroups.com
> <mailto:Indoor_Construction%40yahoogroups.com>, Jake Palmer
> <82.jake_at_...> wrote:
> >
> > I had the fortune to spend some time talking to Larry Coslick at the
> Kibbie
> > Dome this year. I lost 2 motor tubes to motors that broke during or
> after
> > loading them onto the model (one broke just seconds after launch). He
> > mentioned something he's done in the past and I think it's a
> brilliant idea.
> >
> > While he was doing partial motor testing he covered the first 4-5"
> of his
> > motor tube with a leftover piece of another motor tube. He cut open the
> > seam wide enough so it could slip over his motor tube, but narrow
> enough so
> > it stayed in place. The idea is that it's a semi-permanent blast shield
> > that stays on the plane during quarter and half motor testing. Even
> if the
> > motor breaks after launch it will protect the motor tube. It's about a
> > 40-50mg weight penalty, although you can use a lighter partial motor
> stick
> > to offset the weight (just make sure you get your CG right). When he
> > switched to a full motor he removed the sleeve. I plan to use this idea
> > for all my future partial motor tests and I thought I'd share it with
> > anyone else that might find it useful.
> >
>
>
Received on Thu Jul 19 2012 - 16:08:51 CEST