Re: OT: Repeatably lobbing "projectiles"

Don Y <blockedofcourse@foo.invalid> wrote:

We're trying to make a mechanism that will allow for the
REPEATABLE lobbing of small projectiles over short (0-20 ft)
distances.
 
We've tried using a constant force with a variable launch angle
(higher for shorter).
 
And, a variable force with a constant launch angle (push harder
to throw farther).
 
The former seems to be easier to get repeatability.  But, still
not great as it constrains HOW you develop the force to be applied.
 
A ferrous projectile would probably be easier to control
(think: rail gun) but then the projectile starts to become a safety
issue.
 
Now, we're looking at alternate ways of developing that propulsive
force -- e.g., controlled air or water (messy!) pressure.  But,
I suspect qualifying the release valves' performance will prove to
be a stumbling point (and, how it changes).
 
Any other ideas, given latitude in the design of the projectile?

A long cylinder with recesses in its surface into which the projectiles
are loaded.  It is spun rapidly inside a loose-fitting tube and
withdrawn at a steady speed.  The end of the tube where the projectiles
come out is shaped as a scroll with a lip so that the projectiles become
free at a definite angle of rotation.

The speed of rotation could be used to control the velocity and rotating
the outer tube to vary the position of the lip would change the launch
angle.  The whole thing could be made with a screw thread traversing
mechanism like the very earliest experimental Edison tinfoil
phonographs.

--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk