SpudFiles

Ragnarok wrote: Ah. You've made a bit of a boo boo here....

Thanks for the heads up... something didnt seem right in my head and I neglected to pull out my manuals from physics to reference. Spring equations should be ingrained in my head pretty solid after Diff EQ lol...

I'll redo that part and find the appropriate gas springs!


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And a few days later.... I've finally found my method of absorbing the recoil.

First off - screw springs - If I were to stick with a 6 inch spring for this project it would need to be beastly. If I were to use a gas spring for it - it would be so harsh on the return stroke (unless it had amazing dampening... hmmmm)

So after some thorough research in the field of dampening gun recoil - I came across some stuff used by high powered rifles. "industrial shock absorbers" - go figure... i forgot the word industrial in all my previous searches...


Case in point, Using conservation of momentum, I found that my gun would recoil with a maximum velocity of something like 38 ft/s shooting a 1 lb projectile at 880f/s (yes, right around 10K lb ft of muzzle energy). My gun will weight about 25lbs with the sled (now 8020 material).

Using the mass and velocity of just the gun recoiling, I can get the kinetic energy (don't forget to divide weight by gravity!) and so I found I need to look for a shock, or shocks that give me a ceiling value of 7000 in lbs of energy absorption - conveniently that is how shocks are rated in the industrial field - by the total amount of energy they can absorb (within realistic shaft speed values) per compression.

Low and behold I found 2 shocks on ebay that have a 2" stroke and absorb a cumulative 9200 in lbs of energy. They also have adjustable dampening rates (nice for shooting lighter ammo).

And that brings me to the most current version of my design... meh when will I get this thing done? lol.





I'm going to use a section of 40series 8020 material and their respective linear bearing system for the recoil sled for the chamber. Onto this the gun will bolt, and the boss's for the recoil absorbers.

It lives on....

Final version renders... most of the parts are either here, on their way, or about to be ordered, so this is a pretty accurate depiction of what it should look like when i'm done.

Good thing I'm looking a this on my iPhone cuz if I was using my laptop it'd be shorting out!!! *sucks up saliva*

Hell of a cannon you're gonna have there... definitely up there with larda's after it's done, except it's not 200x Sweet man.

If anybody actually has HPA tanks, whether it's small paintball tanks, or industrial tanks, you can easily build something that tests burst disk pressures. An inlet, a high pressure gauge, and union are all that's needed.

Simply put, get a tee, and put a gauge and union on it.

cool.. it has push to connect fittings, solenoid valves and stuff... but where is the loading mech ?

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would be redundant

pretty much as redundant as the solenoid valves

I never really got to finish this gun last year beyond having a set of welded pipes and test firing it a few times with a shitty ignition system... In an effort to get myself in gear for making new and better things ( ) I've decided to finish this and with that came a simplified stand to hold it - sort of what happened with 10 gallon. Mind you - simplified does not mean inferior

So words are useless, heres some photos, and of course the obligatory Mobile Chernobyl Cad drawing of what I hope it will look like... if it turns out anything like 10 gallon it will probably be very close to this drawing...


(Why so many 30deg angles? cause angles make it look bad ass. )

Here is the progress I made tonight - Based on last years test of the soda can bottoms i've decided to flip my unions around (which means cutting out the old one and welding in a new one... ) so that is why the barrel and chamber are bare in the one photo... but also that is an indication of how accurate my fabricated stand has turned out compared to my CAD model sofar







(notice how well chamber and barrel match up!!)


And here is the raw materials I'm using to replace my exiting ignition setup. This is all I'm putting out there though


Oh yea I've decided to hop on the "manometric" train with a retrofit to this guy... say hello to my little friend:

10bar pressure range with .2psi accuracy (.1% FS!) should make things a little easier. perhaps using it's programmable limit switches can be taken advantage of with a favorite mix #...

if you go out and buy a ngk CR10EK spark plug, it will fit 1/8 npt threads.

anyway that thing looks beautiful, cant wait for damage pic/vids.

Oh yea I've decided to hop on the "manometric" train

You made my day!


...the cannon is pretty awesome too

Crna Legija wrote:if you go out and buy a ngk CR10EK spark plug, it will fit 1/8 npt threads.

anyway that thing looks beautiful, cant wait for damage pic/vids.

I'll stick with my design, but thanks for the heads up I may use it on a smaller project... or on my pulse jet so i can finally finish it lol...

880ft/sec! Very impressive with a 1lb projectile. Overall a very nice build. This is going to be LOUD.

Technician1002 wrote:880ft/sec! Very impressive with a 1lb projectile. Overall a very nice build. This is going to be LOUD.

That was with a more ambitious mix than I'm going to take this one up to (and more final pressure than the pressure sensor can measure...)

Heres a more accurate HGDT of what I'll be shooting for heavy loads:


Don't worry the cards are in play for something to wake this forum up.

Ah, hybrid artillery... looking forward to seeing this one in action! One day, I'll make my '88... *looks wistfully towards the horizon*