>I am interested in finding out about methods of stabilization of
>model-rocket-driven projectiles that do not require fins on the outside.
>I want to launch these from a tube...
Back when I was a juvenile-delinquent in high school (now I'm an irresponsible-
***), I developed a tube-launching system for firing rockets at cars, dogs,
and other objects of hatred.
I used a PVC pipe that was about 1/4" wider in diameter than a T-engine. It
was about four feet long. Mounted on the pipe were two handles. Both ends of
the pipe were left open. A trigger on one handle connected a Polaroid
instant-film battery to a pair of metal strips that were folded into the rear
opening of the pipe.
To prepare the rocket-engines for my home-made bazooka, I would first take a
hand-drill and drill into the nozzle of the engine through the propellant--
making the engine into a "core-burning" rocket--while being careful not to
drill into the delay. An Estes solar-igniter was placed as far up the core as
possible (this required removing the tape off the igniter). Each of the ends
of the igniter leads were then wrapped in a folded piece of aluminum foil, and
the foil was taped down to the body of the engine.
Then I would use a strip of duct tape to attach an 8" bass-wood strip as a
stabilizing rod, with a piece of folded-over-itself scotch tape at the end as a
fin. This construction would place the center of pressure behind the center of
T-engine bass-wood stabilizer scotch-tape
Loading the projectile took almost no effort and could be done in less than a
second--all I had to do was shove it into the end of the pipe, and the aluminum
foil tabs would contact the metal strips on the pipe. As soon as a pulled
the trigger, the rocket would literally explode out of the pipe, with enough
accuracy to hit the neighbor's dog at 75 yards.
Quick loading... quick firing. It was an ideal... and cheap system.
If you decide to try out this system... keep in mind that the launching pipe
can't be metal--or you'll short out the metal ignition strips. And PVC is
*much* lighter, and therefore more portable (i.e. you can run faster with it
when you get chased by the angry owner of the car with the shot-out window).
The bass-wood stabilizer isn't too important if your pipe is long enough and
you don't need pin-point accuracy. As long as you core-burn your
rocket-engines, the propellant will burn *completely* while the rocket is still
inside the pipe--so once the rocket has left the piep, it will travel in a
relatively straight line. (If you've experimented with shooting finless
rockets out of pipes, you've probably figured out that if the propellant is
still burning once the rocket has left the pipe, the rocket will spin
The rockets were tested with/without the tape on the end of the stabilizer. It
*seemed* like the tape increased accuracy. (At least it never seemed to
decrease it.) And unbelievably, it was never burned off by the exhaust.
If you need more detail, send me a quick note and I'll try to answer whatever
questions you might have about this system.
skate safe. andy.