Date: Thu, 18 Nov 2004 15:05:40 -0500

Author: Richard Flarend

Subject: Re: Vacuum Bazooka

Post:

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I have a great success rate. I haven't had a misfire in at least 20
attempts or so. I use extra wide packing tape and take great care in
sticking it onto the ends of the pipe. (Incidentally, the ends of my
pipe are just cut PVC sanded reasonably smooth with standard sandpaper.

I have a long version and a short version. I use the long version for
stage shows just because it appears more impressive. But I also have to
clamp it into place in at least 3 places to make sure it is straight.

What is with the 40 mm balls? Are these standard ping-pong ball sizes?
I just buy whatever K-mart has and don't pay much attention to it. I
have some oversized balls that I am thinking about trying. Has anyone
used those before? What size pipe is used?
Richard F.


Cliff Bettis wrote:

>David,
>
>Be sure you're using 40 mm balls. Although the can holder I built isn't
>necessary, it certainly speeds set up and makes it easier for people other
>than me to set it up. Make sure your bazooka holds a good vacuum; I had a
>leak around the valve that puzzled me for a while. Check after firings to
>make sure the barrel isn't fouled with bits of tape, Mylar or foil (whatever
>you use to seal the ends). My cans are about 3/16 " apart held firmly by the
>can holder.
>
>Cliff
>
>PS Oh, be sure to empty the cans before using, especially if they're beer
>cans. ;-)
>
>----- Original Message -----
>From: "David Willey"
>To:
>Sent: Thursday, November 18, 2004 7:14 AM
>Subject: Re: Vacuum Bazooka
>
>
>
>
>>Greetings all,
>>I'm still trying to optimize my vacuum bazooka. I remember there was
>>mention of the optimum length for getting the greatest speed, could
>>someone please tell me what that was? Also, when you set up the cans,
>>what space do you leave between them, if any, and do you put any weights
>>on top? Thanks for any help that's offered,
>>cheers,
>>David
>>
>>Eric Ayars wrote:
>>
>>
>>
>>>I suspect that it's not the can setup that's causing your problem,
>>>because 370 mph is on the low side. I typically measure the ball speed
>>>as being between 400 and 550 mph. That's with a 1.8m barrel and Al
>>>foil on the ends rather than tape. (My results with tape are generally
>>>slower.)
>>>
>>>I don't use a can holder --- I just set the cans in a line in front of
>>>the cannon.
>>>
>>>
>>
>>
>
>
>
>
>

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I have a great success rate.  I haven't had a misfire in at least 20
attempts or so.  I use extra wide packing tape and take great care in
sticking it onto the ends of the pipe.  (Incidentally, the ends of my
pipe are just cut PVC sanded reasonably smooth with standard
sandpaper. 



I have a long version and a short version.  I use the long version for
stage shows just because it appears more impressive.  But I also have
to clamp it into place in at least 3 places to make sure it is straight.



What is with the 40 mm balls?  Are these standard ping-pong ball
sizes?  I just buy whatever K-mart has and don't pay much attention to
it.  I have some oversized balls that I am thinking about trying.  Has
anyone used those before?  What size pipe is used?

Richard F.





Cliff Bettis wrote:

cite="mid001101c4cd7b$63639a80$96245d81@lecturedemo">
David,

Be sure you're using 40 mm balls. Although the can holder I built isn't
necessary, it certainly speeds set up and makes it easier for people other
than me to set it up. Make sure your bazooka holds a good vacuum; I had a
leak around the valve that puzzled me for a while. Check after firings to
make sure the barrel isn't fouled with bits of tape, Mylar or foil (whatever
you use to seal the ends). My cans are about 3/16 " apart held firmly by the
can holder.

Cliff

PS Oh, be sure to empty the cans before using, especially if they're beer
cans. ;-)

----- Original Message -----
From: "David Willey" <dwilley+@pitt.edu>
To: <tap-l@listproc.appstate.edu>
Sent: Thursday, November 18, 2004 7:14 AM
Subject: Re: Vacuum Bazooka




Greetings all,
I'm still trying to optimize my vacuum bazooka. I remember there was
mention of the optimum length for getting the greatest speed, could
someone please tell me what that was? Also, when you set up the cans,
what space do you leave between them, if any, and do you put any weights
on top? Thanks for any help that's offered,
cheers,
David

Eric Ayars wrote:



I suspect that it's not the can setup that's causing your problem,
because 370 mph is on the low side. I typically measure the ball speed
as being between 400 and 550 mph. That's with a 1.8m barrel and Al
foil on the ends rather than tape. (My results with tape are generally
slower.)

I don't use a can holder --- I just set the cans in a line in front of
the cannon.













--------------090009060704000102070200--
From stjohn@buphy.bu.edu Thu Nov 18 15:04:56 2004

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