On Sun, 29 Nov 2009 10:17:37 -0500, "Ralph Mowery"
wrote:


"Howard K0ACF" wrote in message
.. .
The pipe for the barrel is 1 1/4 in. 24 in. long. The end caps for the
projectile are 3/4 in. so there is not to much of a loose fit. I haven't
made one myself but a friend of mine has & it does just like the article
say's, use with caution & safety. I'm interested how it works with a
tennis ball, that sounds real neat. Howard K0ACF
"John Ferrell" wrote in message

I don't have that QST but I built one like this:
http://www.qsl.net/k5lxp/projects/La.../Launcher.html

I did wrap a couple of layers of electrical tape over the end caps I used.
Found some orange electrical tape that I thought would make it easier to
see..
Still sort of loose in the pipe. At 35 psi it will shoot them to about 60
feet or more. My first trial shot put it over my triband beam that is about
55 feet up. Did not mean to do that but just wanted to get the feel of how
much psi I should use. I have found 45 psi will put it over the tops of the
trees here that are over 70 feet tall.


That is the model that I planned to use if the available Sprinkler
valve had that particular configuration. I was concerned about this
model because of the barrel and the tank being of equal volume. It is
good to have the testimony that it works as well! I be live it would
be easier to build and cost a little less as well. I would lean toward
the 1-1/4" barrel bore and the 3/4" tubing projectiles because I have
yet to see the 1" end caps described locally.

I may get to try a paper towel for a "patch" as used in Black powder
fire arms tomorrow. I am anxious to get up the 160 meter inverted L.

John Ferrell W8CCW