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Sleek Streamlined Golfball Launcher

Post questions and info about combustion (flammable vapor) powered cannons here. This includes discussion about fuels, ratios, ignition systems, safety, and anything else relevant.
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Sleek Streamlined Golfball Launcher

Unread postAuthor: Cthulhu » Tue Dec 18, 2018 10:04 pm

I wanted to make a combustion cannon that would not only have great performance, but also would be sleek and durable with an endless supply of high performance ammo.
So I decided to make this.

The cannon is a 4 foot piece of 2" Sch. 80 PVC with a 3 foot long section of 1.5" sdr21 shoved into it to make the barrel. The body of the cannon also operates as the combustion chamber, making it require almost no fittings!
To bump up the performance, I rigged together a 5 spark electric barbeque igniter (which took some fiddling with to get to work). Finally, to make fueling fast and easy with no fumbling, I added a ball valve at the rear to make fueling fast and easy. It is meant to fire golf balls.

golfball bazooka.png
the basic design plan
golfball bazooka.png (12.87 KiB) Viewed 806 times


I also glued a few cut pieces of pvc inside the barrel to work as a ball catch, preventing the golf ball from rolling into the chamber.
IMG_20181121_230656.jpg
The ball catch


The screws not connected to the bbq igniter had to be connected to each other (for magical electrical reasons as I was told by my electrical engineering friends :lol: )
IMG_20181125_162028.jpg
a strip of metal I found with holes already drilled in it worked great for connecting the receiving electrodes!

But it was definitely worth it.
IMG_20181125_233658(1).jpg
5 beautiful sparks!


The problem I've been having is figuring out a way to effectively attach the igniter so that it can be fired over the shoulder (like a bazooka).
IMG_20181218_205219.jpg
The dangling chords and igniter don't make this very ergonomic...
You can see I glued a piece of pvc sliced in half over the connected electrodes so that the metal strip doesn't snag on clothing.


Does anyone have any ideas on how to attach the igniter? Suggestions on how I should paint it and optics for aiming would also be amazing :P
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This weapon serves to silence the noisy speakers of the stupid of the other street! (joke) -Hectmarr
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Re: Sleek Streamlined Golfball Launcher

Unread postAuthor: jackssmirkingrevenge » Wed Dec 19, 2018 9:31 am

Nice, how are you metering the fuel?

The problem I've been having is figuring out a way to effectively attach the igniter so that it can be fired over the shoulder (like a bazooka).


Tee connection on the barrel?
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hectmarr wrote:You have to make many weapons, because this field is long and short life
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Re: Sleek Streamlined Golfball Launcher

Unread postAuthor: Cthulhu » Wed Dec 19, 2018 12:02 pm

jackssmirkingrevenge wrote:Nice, how are you metering the fuel?

Took your advice and used syringe metering, so far it works great. The thing likes to eat 20mL of butane and HGDT says I should be getting over 300fps with that!

jackssmirkingrevenge wrote:Tee connection on the barrel?


I thought about using a T-fitting with a slot cut in it to fit the igniter module, but I think that the module is larger than the diameter of the 2"pipe so it might not fit unless I do some heat bending.
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Re: Sleek Streamlined Golfball Launcher

Unread postAuthor: Cthulhu » Thu Dec 20, 2018 12:40 pm

IMG_20181220_112643.jpg
Lookin' good! Still needs some paint though.

Made great progress! :D
Took the advice and used a T-fitting cut with a piece of pipe cut in half. I didn't bother with the heat bending and just hot glued the module to the sliced pipe and it was sturdy enough.
I also added a foregrip for stability, zip tied the wires down to keep them organized, and glued another half pipe of PVC to the other electrodes to protect my face from being shocked if I accidentally push me cheek too close to the pipe.
It's pretty comfy to hold! And since the cannon is so heavy there is very little recoil.

Anyone have ideas on a cool paint scheme or what kind of optical system I should attach to it?
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Re: Sleek Streamlined Golfball Launcher

Unread postAuthor: jackssmirkingrevenge » Fri Dec 21, 2018 9:09 am

Looking good!

Anyone have ideas on a cool paint scheme or what kind of optical system I should attach to it?


OD Green would be traditional, and I would go for a cheap Chinese red dot or low magnification scope on the side, have a look at recoilless rifles for inspiration.
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hectmarr wrote:You have to make many weapons, because this field is long and short life
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Re: Sleek Streamlined Golfball Launcher

Unread postAuthor: hectmarr » Fri Dec 21, 2018 10:57 am

have a look at recoilless rifles for inspiration.

Interesting article on this topic. I have managed to completely eliminate this undesirable effect, by moving the valve piston of HA II and III backwards, I mean towards me. You can put a cork on the gun and it does not fall. It's easier to hit the target.
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Re: Sleek Streamlined Golfball Launcher

Unread postAuthor: jackssmirkingrevenge » Fri Dec 21, 2018 12:53 pm

Here's a nice demonstration of how effective the recoilless principle is in practice:

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Re: Sleek Streamlined Golfball Launcher

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Re: Sleek Streamlined Golfball Launcher

Unread postAuthor: wyz2285 » Fri Dec 21, 2018 2:30 pm

So it's basically a rocket but the propellent isn't onboard... The twist to cancel the rifling is very well thought tho.
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Re: Sleek Streamlined Golfball Launcher

Unread postAuthor: hectmarr » Fri Dec 21, 2018 3:03 pm

jackssmirkingrevenge wrote:Here's a nice demonstration of how effective the recoilless principle is in practice:


wow !!! :shock: Impressive effect of this "magical" design!
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Re: Sleek Streamlined Golfball Launcher

Unread postAuthor: Cthulhu » Fri Dec 21, 2018 6:53 pm

jackssmirkingrevenge wrote:OD Green would be traditional, and I would go for a cheap Chinese red dot or low magnification scope on the side, have a look at recoilless rifles for inspiration.


Good idea! I have both of those on hand right now! Hopefully I'll be able to find a way to make dovetails for my scope to attach to though (maybe strips of pvc sanded down until they fit).
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Re: Sleek Streamlined Golfball Launcher

Unread postAuthor: jackssmirkingrevenge » Sat Dec 22, 2018 9:01 am

Cthulhu wrote:Hopefully I'll be able to find a way to make dovetails for my scope to attach to though (maybe strips of pvc sanded down until they fit).


Isn't it easier and simpler to just buy something like these for a few bucks and bolt them on?

So it's basically a rocket but the propellent isn't onboard


In the case of the M18 in the video, not exactly. What happens is that instead of being completely contained by the barrel, some of the gas is vented at high velocity towards the rear of the launcher. This gas effectively turns the barrel into a rocket wanting to move forwards. When properly designed, this force is identical to the recoil force trying to push the barrel back, meaning that it cancels out.

The weapon that is sort of a rocket but not quite is the Panzerfaust where instead of the propellant being contained in a tube that is part of the rocket, the tube is actually the launcher and it's the propellant that moves down it. The Soviet RPG system uses the same principle for the initial launch of the projectile, though it is the rocket motor which ignites later that provides most of the motive force.
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hectmarr wrote:You have to make many weapons, because this field is long and short life
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Re: Sleek Streamlined Golfball Launcher

Unread postAuthor: Cthulhu » Sat Dec 22, 2018 3:06 pm

jackssmirkingrevenge wrote:Isn't it easier and simpler to just buy something like these for a few bucks and bolt them on?


If I wasn't an unemployed college student then maybe!
Until I have income I'll have to settle for hodgepodge pvc construction :lol:
IMG_20181222_135606.jpg
good 'nuff for now
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Re: Sleek Streamlined Golfball Launcher

Unread postAuthor: jackssmirkingrevenge » Mon Dec 24, 2018 9:06 am

товарищ, it works!
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