UPGBH10x

Harness the power of precision mixtures of pressurized flammable vapor. Safety first! These are advanced potato guns - not for the beginner.
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DYI
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Fri Apr 09, 2010 8:48 pm

I just noticed the two 1200 frame/s videos you posted on the front page. Very nice. I especially enjoyed being able to see the interaction of the projectile's pressure wave with the ground.

I look forward to seeing how the craters made in clay by golfballs compare to those I've done with airsoft rounds :lol:

Finally, I second SB15 on the marble grapeshot. A thin casing to prevent damage to the barrel may be worth looking into.
Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
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SpudFarm
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Sat Apr 10, 2010 6:06 am

DYI wrote:I just noticed the two 1200 frame/s videos you posted on the front page. Very nice. I especially enjoyed being able to see the interaction of the projectile's pressure wave with the ground.

I look forward to seeing how the craters made in clay by golfballs compare to those I've done with airsoft rounds :lol:

Finally, I second SB15 on the marble grapeshot. A thin casing to prevent damage to the barrel may be worth looking into.
It did come out pretty nice. I may get to do some shots today but the weather is kind of threatening.
I have ordered 20kg clay for now and it will arrive thursday they said.

The grapeshot will be tanken today if the weather gets better.
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Ragnarok
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Sat Apr 10, 2010 8:10 am

SpudBlaster15 wrote: Yeah, it's kind of a shame that hybrid cannons aren't more popular. Complex launchers just don't appeal to many people.
I'm not sure how accurate it is to say that. Hybrids aren't all that complex in mechanical terms. They're really just a combustion with a burst disk and compressed air input.

What they are is quite a lot of effort to operate, given that the valve needs to be rebuilt every shot, and then the chamber needs to be carefully re-metered and pressurised each time.

If you want to get around that, then there is quite a lot of effort to build and install a re-sealing valve and automatic metering system. But hybrids are not automatically complex - they're either quite a bit of work to operate, or complex, but not really both.
Does that thing kinda look like a big cat to you?
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SpudFarm
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Sat Apr 10, 2010 9:23 am

I did shoot again today, this time the target was some boards with a door behind it and one shot on just the door.
The second shot where supposed to be a buck shot but the shot never left is wadding.. It did make a neat hole though.
I know the second shot was super sonic because of the change in noise.

The video has all the info one could possibly need and is on the first post.
SpudBlaster15
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Sat Apr 10, 2010 2:57 pm

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Last edited by SpudBlaster15 on Wed Jul 14, 2021 7:47 pm, edited 1 time in total.
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SpudFarm
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Sat Apr 10, 2010 3:23 pm

SpudBlaster15 wrote:
SpudFarm wrote:The second shot where supposed to be a buck shot but the shot never left is wadding.. It did make a neat hole though..


Perhaps using a Styrofoam sabot instead of wadding would allow the shot to leave the barrel unimpeded?


Yes, that is what I am going to use in the future. But since it is weekend I haven't got any yet. And cloth seemed as a reasonable choice at the time :P

I do also agree with SB on the discussion that him and Ragnarok has. Hybrids are not very hard to make but not many dedicate enough of their time to research to make a hybrid, they rather just make a simpler design.

Small hybrids (even with unions) can be fired once every minute if you have a non-charging ignition system, manometric metering and enough burst disks to satisfy your needs.
Just screw apart the union, load the projectile in the breech, put the union back together with the disk, open fuel/air valve to desired pressure and fire.
A pneumatic with threaded breech loading system (wich most have) require the same steps if you look away from opening the fuel valve and putting a simple disk in place before screwing the barrel/union back on.

I simply cant see why there aren't more hybrids.

They are not complex, just takes a bit sturdier design.

A big hybrid can be reloaded almost as quickly, the problem is to carry it out in sections and putting it together. When that is done I can just unscrew the union and push the barrel forward to put a new disk in.

I guess I agree with both of you in some way.
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daberno123
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Sat Apr 10, 2010 6:31 pm

To speed up cutting out burst disks, there are large diameter hole punches like this which can punch through aluminum foil. A disk cut from a 2" punch fits perfectly into a 2" union.
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Ragnarok
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Sat Apr 10, 2010 7:14 pm

SpudBlaster15 wrote:While they're not incredibly complex in an absolute sense, hybrid cannons are significantly more difficult to built, understand, and operate than traditional pneumatic and combustion launchers.
Yeah, but most of that really comes under my original point of "more effort".

Like I say, in basic terms, a hybrid is a stronger combustion with a burst disk and compressed air valve - it takes more than just passing DIY skill to make one, but most of the regulars could pull the construction off quite easily.
Actually getting that "stronger combustion with a burst disk and compressed air valve" working is what takes the application of effort.

Let's take me as an example. I don't think you'd doubt my ability to build or understand a hybrid - so, they're not factors affecting my choice of whether to build one.

The two things that put me off are:
1) Effort required for each shot.
2) Usually, hybrids are not looked upon as man-portable. I like to be able to handle my launchers. Setting them up for a shot, then backing off 30 feet and pressing a button feels like a scientific experiment. Sure, it's not impossible to have a hand fired hybrid, but they're a minority.

I've only got one hybrid design I've got that I would really like to get built, and as you might imagine, it's also the one that handles both of those problems.
Basically, it's best described as a hybrid assault rifle. Very little effort expended on each shot (pull trigger - if it doesn't fire, manually cycle the "cocking handle" and try again), and with the same kind of handling.

The problem of course is that it IS mechanically complex (machining would be a necessity).
With cam lock fittings, rebuilding the valve only adds a few seconds to the time required to load the projectile.
I wouldn't say so. If you count the time required to make the burst disk, then it adds up to quite a bit longer than it takes to reset a typical pneumatic valve.

Although, one thing I'm still waiting to see is Gort's QCTBD valve used on a hybrid - seems like something that should really have been capitalised on before now.
Does that thing kinda look like a big cat to you?
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kjjohn
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Sat Apr 10, 2010 7:42 pm

I basically agree with Ragnarok. I am currently building a hybrid, in fact, a piston valved, one, and although hybrids are very complex, I am convinced that with the design I will be using, and with the amount of money I am spending on it, I can make it practical and portable. Whats unusual, is that I have never built an advanced combustion. I have pneumatic experience, but nothing else.

So, I definitely think that anyone on this site who really knows what they are doing could build a hybrid.

By the way, what is Gort's QCTBD valve? I have never heard of it anywhere else on the forum.
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Ragnarok
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Sun Apr 11, 2010 2:21 am

kjjohn wrote:By the way, what is Gort's QCTBD valve? I have never heard of it anywhere else on the forum.
Well, the valve off the Quick Change Triggered Burst Disc Cannon.

It uses the chamber's own pressure to clamp the burst disk in place.
Does that thing kinda look like a big cat to you?
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SpudFarm
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Sun Apr 11, 2010 6:30 am

daberno123 wrote:To speed up cutting out burst disks, there are large diameter hole punches like this which can punch through aluminum foil. A disk cut from a 2" punch fits perfectly into a 2" union.
Hmm, That looks promising. If I can find something like that in Norway I will test it out.

Thanks.
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starman
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Sun Apr 11, 2010 8:58 am

SpudFarm wrote:One more, hybrid topics needs to be bumped since no one looks at them otherwise. Front page a golf ball for starman :P I lack a melon though :/
And a big thank you for those awesome golfball shots, especially the slo-mo one...t'was a thing of beauty.

Can you even get a watermelon in Norway this time of year?
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Heimo
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Sun Apr 11, 2010 9:17 am

SpudFarm wrote:
daberno123 wrote:To speed up cutting out burst disks, there are large diameter hole punches like this which can punch through aluminum foil. A disk cut from a 2" punch fits perfectly into a 2" union.
Hmm, That looks promising. If I can find something like that in Norway I will test it out.

Thanks.
or you can use something like this
Image
I have seen them go up to 40mm diameter
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SpudFarm
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Mon Apr 12, 2010 7:16 am

starman wrote:
SpudFarm wrote:One more, hybrid topics needs to be bumped since no one looks at them otherwise. Front page a golf ball for starman :P I lack a melon though :/
And a big thank you for those awesome golfball shots, especially the slo-mo one...t'was a thing of beauty.

Can you even get a watermelon in Norway this time of year?
Thank you, if I get the money needed I might end up buying a second camera so I can have both HD and high speed footage of each shot. Just high speed gets a bit boring with no sound.

Yes I can, not that I am a fruit expert but I would be dissapointed if I couldn't

Currently I am sick, I can see if I can get a melon tomorrow if I get better.

Heimo: I think I can make that out of a pipe the right diameter, I imagine those are expensive when having a 5cm diameter.
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Heimo
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Mon Apr 12, 2010 7:26 am

SpudFarm wrote:
Heimo: I think I can make that out of a pipe the right diameter, I imagine those are expensive when having a 5cm diameter.
that is a good Idea and It will probably work good too..
The voices in my head may not be real, but they have some good ideas!
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