According to chris m :
> > I've been using some Nomex fabric shields instead of wadding in my
> > small rockets, with good results. Is this common practice in larger
> > rockets, or do people typically prefer piston designs, or even > > wadding?
>
> In larger diameter rockets, the risk with wadding is that you may
> have a narrow "blowthru", and if the chute isn't plugging the
> tube, the chute might not get chucked out with sufficient force
> to avoid hangup. As long as the BT separates, you _should_
> have enough yank to get the chute the rest of the way out, but
> sometimes, maybe not.
My ground testing has consistently shown me that the chutes in bigger rockets (7.5") are not ejected by the ejection charge, whether they are in a deployment bag, wrapped in nomex, or just using wadding. Add the NC strap, and they get pulled out. Leave the strap off, and the NC goes flying but the chute stays put, whether it's tight or loose in the BT.
My 2 cents.