Over-Under Propane 1st Timer - Updated!!!
Posted: Sun Mar 11, 2007 12:40 am
This is my first serious attempt at a propane injected cannon.
It has a 80mm chamber fan which is actuated by a small switch just above and in front of the front grip.
The ignition system is a dual spark set up with a 100,000v stun gun for power. The stun gun's trigger has been relocated to the rear grip.
The gun was originally meant for static guard, so it has a 1.5 to 1 C:B ratio. It will launch a potato 250-300 yards and is really dependable. I know the design is not that uncommon. The first time I saw a gun of this design, I had to have one.
Ok I have taken some of your excellent advice and made some revisions which have really paid off.
First, as you can see, Bertha now sports a 7 ft 6 inch barrel to bring the C:B ratio to 1 to 1. I then moved the dual spark from the barrel side of the chamber to the cap side. I also wired another 9 volt battery in series to the fan so it is now an 18 volt system.
I made each change independant of the others so I could evaluate the increased performance of each change. All of them have made drastic differences but I'd have to say that the added benefits gained from the increase in fan rpms really shocked me. It now has a loud solid crack instead of a low, slow thump when let off, and although not measured yet, the distances and speeds appear to be much higher.
Has anyone else noticed a marked addition in performance after changing your fan or increasing the voltage/rpms of the fan?
It has a 80mm chamber fan which is actuated by a small switch just above and in front of the front grip.
The ignition system is a dual spark set up with a 100,000v stun gun for power. The stun gun's trigger has been relocated to the rear grip.
The gun was originally meant for static guard, so it has a 1.5 to 1 C:B ratio. It will launch a potato 250-300 yards and is really dependable. I know the design is not that uncommon. The first time I saw a gun of this design, I had to have one.
Ok I have taken some of your excellent advice and made some revisions which have really paid off.
First, as you can see, Bertha now sports a 7 ft 6 inch barrel to bring the C:B ratio to 1 to 1. I then moved the dual spark from the barrel side of the chamber to the cap side. I also wired another 9 volt battery in series to the fan so it is now an 18 volt system.
I made each change independant of the others so I could evaluate the increased performance of each change. All of them have made drastic differences but I'd have to say that the added benefits gained from the increase in fan rpms really shocked me. It now has a loud solid crack instead of a low, slow thump when let off, and although not measured yet, the distances and speeds appear to be much higher.
Has anyone else noticed a marked addition in performance after changing your fan or increasing the voltage/rpms of the fan?
chichen isnt realy much of an excuse because that are pretty safe when built right