Anyone doing anything with Rocket Motors besides fly them?

[TBerk]

Just brainstorming but I was wondering if anyone was (for example)
Drag Racing or Speed Boating, maybe even the opposite of striving for
hight; Deep Water Depth Challenge.

How would someone shoot a 'rocket' straight down into the water and
have it 'breath' and not go out? How would you know just how far it
got? What would you construct it out of, and for that matter; how to
recover it (depth performance vs buoyancy, etc).

Hmmm.

berk

[temps...@hargray.com]

It doesn't need to "breathe" as it takes both fuel *and* oxidizer
along inside the motor. Besides, if it "breathed" how would oxygen
get into the motor with all the exhaust coming out?

[TBerk]

Hey, hey! _I'll_ be asking the rhetorical questions around here!

But really though, valid points. I sometimes sacrifice a thorough
thinking-though during brainstorm sessions.

berk

[Todd]

I am building a rocket car, a BIG one. I've made little ones by
outfitting plastic toy cars with D engine mounts and they've worked
pretty well, but my best (straightest) one got up to probably 30 mph
and went maybe 100 yards with coasting.

This car is about 6 feet long with 12" wheels, an 8" PVC pipe as a
body and a LOC 7.5" nose cone. It'll have a 54mm motor mount in it
with a 38mm adaptor for initial runs. I have about 1500' of wire for
it to run on. Weigh in is at around 40 lb fully loaded. With an I161
to start, my calculations say it'll get up to about 15 mph and roll
100'. If I stuffed a K700 in it my math works out to well over 200
mph and a hard chute is needed to keep it from running the full length
of the wire. We'll see!

Todd

[Todd]

Another potential idea: Underwater launch. I've often thought of
taking a PVC tube, loading it with a rocket, sealing it off with seran
wrap, mounting it underwater with maybe 2-3" of water over the top,
and then launching the rocket submarine ICBM style. I wonder if it
would work or the rocket would just crumple trying to get through the
water?

[lektr...@gmail.com]

I've done this before. Used a tall kitchen-style trashcan and wedged
a wood block with a launch rod in the bottom. I don't remember how
much we filled it up, I don't think it was over the top of the rod.
We launched several rockets by just prepping the engine and taping it
in place (this was back in the days when you bent the igniter, pushed
it and a small ball of tissue into the engine, then covered it with a
piece of tape). Attached the ignition leads, slid the rocket down the
rod and fired it before water could soak in. Made a big blast and
sprayed water everywhere when the rocket exited the "bucket".

I've also made tube launchers (out of water this time) that used a
large diameter (3.75" I think) thin-walled tube and "slippers" between
the fins/body and the tube. I call the adapters "slippers" rather
than "sabots" (French for wooden shoe) because my adapters run down
the length of the rocket rather than just around the circumference. I
made a nice semi-scale patriot that I launched this way. One thing I
DID learn is that you need a powerful engine to get the rocket out of
the tube (at least mine did). I tried launching the patriot on an A
and it didn't make it out of the tube.

[Todd]

>
> I've done this before.  Used a tall kitchen-style trashcan and wedged
> a wood block with a launch rod in the bottom.  I don't remember how
> much we filled it up, I don't think it was over the top of the rod.
> We launched several rockets by just prepping the engine and taping it
> in place (this was back in the days when you bent the igniter, pushed
> it and a small ball of tissue into the engine, then covered it with a
> piece of tape).  Attached the ignition leads, slid the rocket down the
> rod and fired it before water could soak in.  Made a big blast and
> sprayed water everywhere when the rocket exited the "bucket".
>

Wow, that sounds cool. I'm surprised the water didn't ground the
igniter leads.