[AR] Re: 500,000 tons

  • From: Rob Davidoff <rwdavidoff@xxxxxxxxx>
  • To: arocket@xxxxxxxxxxxxx, Ben Brockert <wikkit@xxxxxxxxx>
  • Date: Thu, 8 May 2014 22:16:31 -0400

Ben,

My school's local AIAA section had a similar thing we'd do using straws
with the tip plugged with clay. Less pressure and speed, and accordingly
lower distance, but they were slow enough and light enough that we could
set it up indoors at youth outreach events without anyone putting an eye
out. This is a launcher similar to what we
used<http://www.pitsco.com/Straw_Rocket_Launcher>,
the straws were just standard straws bought from the grocery store. Plug
the nose with clay, and the kids could design their own fins out of
cardstock or paper. We'd put a box or hula hoop downrange, and let them aim
or it--if they got in, they won a sticker or candy or something. Cheap
demo, and the kids enjoyed it.

A little less impressive than your film canister rockets, I suspect, but
straws are a lot easier to come by and not going anywhere soon--I'm pretty
sure if you're not looking to shell out $170 bucks for a pre-built
launcher, you could make something yourself that was even a bit more
powerful using compressed air.

-Rob Davidoff


On Thu, May 8, 2014 at 4:31 PM, Ben Brockert <wikkit@xxxxxxxxx> wrote:

> The film canister is just pushed over a loose-fitting plug the size of
> the inside of a film canister. It's not retained except by a bit of
> friction, so it launches off before it has to hold 60psi. The plastic
> canisters are used. It's like an inside out mortar, were the mortar
> flies off after the plug/cannonball pressurizes it.
>
> A decade ago when I started the outreach using film canisters we could
> stop by the local photo shops, Target, etc. and they'd give us bags of
> them. Getting a bit harder to find now. It's probably time to find a
> replacement canister that can be bought in big bags from China.
>
> On Wed, May 7, 2014 at 5:44 AM, Redacted sender monsieurboo@xxxxxxx
> for DMARC <dmarc-noreply@xxxxxxxxxxxxx> wrote:
> > Pretty soon the only ones who'll recognize the term "film canister" are
> the
> > ones who grouse "Get off my lawn, you young punks!"  So I'm wondering are
> > these the really old-school metal cans or the "contemporary" plastic
> ones?
> > And now I'll have to troll ebay and the internet to find where to obtain
> > said memorabilia.  Someday they'll be as valuable as unopened cans of
> Billy
> > Beer.
> >
> > Your description makes it sound as if the first method air-pressurizes
> the
> > canister itself to 60psi, is that correct?  And that'd surely have to be
> the
> > metal screw-top version with the semispherical dome at the apex of the
> > chamber, right?  Appropriate design touch, that.
> >
> > With so many local jurisdictions adopting the Fire Code to govern
> low-power
> > rocketry activities, it's become considerably harder to arrange hands-on
> > activities that teach rocketry to young people.  This has great
> potential.
> >
> > Cheers,
> > Mark L.
> >
> > They'd make
> > a construction paper rocket with a film canister in the base, then
> > mount it on the launcher which was some plumbing pumped to 60psi with
> > a bicycle pump (by the kid if they were large enough).
> >
> > We did a similar thing at Iowa State, using alka seltzer and water in
> > the film canisters to make carbon dioxide and launch the rockets
> > upward. But the air system was so much cleaner and more powerful.
> >
> >
> >
>
>

Other related posts:

  1. Home
  2. arocket
  3. Archive
  4. 05-2014