[HCARC] Compressed Air Gun - Antenna Launcher

[Lee Besing]

Just remember that shooting a hard metal obje t up into the air, can be dangerous to anyone on the receiving end. 

A friend of mine, Bryce Weathersby,  KE5KFD, member of both Hill Country REACT Team and the San Antonio Radio Club, built one of these last year, using a tennis ball as the "bullet". He used his cheap Harbor Freight air compressor to pump it back up. Yes, having the gauge was very important to prevent damage. 

Knowing Bryce,  he would likely be willing to share his experience with any other interested hams as well.

Lee Besing, N5NTG
210-771-7075 ( voice/text)
San Antonio, TX



-----Original Message-----
From: Bill Tynan <billandmattie at windstream.net>
To: 'Gary J - N5BAA' <qltfnish at omniglobal.net>, hcarc at mailman.qth.net
Sent: Tue, 27 Jan 2015 10:28 PM
Subject: Re: [HCARC] Compressed Air Gun - Antenna Launcher

Gary:

Gary:

Very ingenious:

Instead of the fishing sinker, you might consider the right size egg
insulator. Since they have holes, it's easy to attach the line. 

73,

Bill, W3XO



-----Original Message-----
From: HCARC [mailto:hcarc-bounces at mailman.qth.net] On Behalf Of Gary J -
N5BAA
Sent: Tuesday, January 27, 2015 8:50 PM
To: hcarc at mailman.qth.net
Subject: [HCARC] Compressed Air Gun - Antenna Launcher

Has anyone ever made or used a PVC compressed air gun for shooting line over
trees for putting up antennas??  I have solved all the parts including a
rubber tire valve already installed into a PVC pipe cap and have some 1/2
inch PVC that has a smaller inner diameter than the stuff sold at Lowes,
which just happens to perfectly fit some 3/4 ounce steel egg shaped fishing
sinkers available at WalMart.  The sinkers are almost a perfect fit for the
1/2 inch PVC.  I am using a 3/4 inch PVC in-line valve for the trigger.  The
one model I have seen in QST costs about $65.00 for $10 bucks worth of
parts.  I plan to pump the  15-18 inch long 3 inch diameter PVC reservoir
with between 70-100 psi of air.  The PVC is rated for 600 lbs pressure if I
remember correctly, so my working pressures should be safe.  I am not sure
how long to make the barrel for maximum muzzle velocity - assuming I want
maximum muzzle velocity, since I don't want to launch the bullet all the way
to the next county - just over a 50 + foot tree.

All of the PVC was purchased at Lowes except for the 1/2 inch and I have
enough to make almost anyone interested a barrel.   I'll bring the gun to
the next meeting (assuming it passes it's beta testing of course) for
general critique.  I am trying this method since most of attempts to utilize
a slingshot have met with banged up fingers and a tendency for the sinker to
curve to one side or another in flight due to the sinker being asymetrical.
The sinkers I am using are pretty regular in shape and hopefully will fly
pretty straight.  Once the PVC air chamber is charged with air, all it takes
between shots is a common hand tire pump to top off the pressure for the
next shot.

Gary J
N5BAA
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