Lane's .308 Lightning Build (log)

[Lane]

8 hours ago, DNP said:

How do they treat air rifles?  By definition, this should not be a firearm…right?

I thought about that; but reading definitions of various technical words involved made me a lot less certain. 

A quick glance at actual air gun laws seem to only specify air or spring power only; magnetic or electric power does not seem to be included. There is a definition for "electric dart gun"; but it appears to require the device to shock the target which doesn't apply here. Armor piercing ammunition happens to be defined as any projectile of steel, etc. etc.; so I'm not even sure if I technically run afoul with that... Might need to stick with induction "drive" instead of reluctance, and be forced to use aluminum (which isn't all bad, keeps me closer to my weight target for full size projectiles). Is a steel BB exempt because it was fired from an air rifle; or is this another case of illogically overlapping laws?

Don't forget. NYC requires a license for BB, pellet, and airsoft guns. Probably paintball guns too. I would not be shocked at all to find out that the whole state of NY is governed by some extremely poorly conceived laws that might apply in this situation. Quite frankly; I still can't even find the NY state legal definitions of some of these terms used in the laws I am aware of.

Could you imagine having to go to a NYC gun range to shoot your BB gun (and wouldn't that be embarrassing)?!?!? They see me rolling up to the range in my Dodge Aries; getting out with a larger, locked case in hand. Go inside to check in; showing my club membership card, NYC license to posses, drivers license, and then information for an emergency contact. Once that is recorded in the ledger and notarized, I am finally issued a lane assignment and proceed to a shooting station... Unlock the case that has been handcuffed to my wrist to reveal a mint Daisy Powerline 340 with red oak grips and extra unloaded magazines in the foam cutouts; alongside and a tube of 350 premium projectiles. Then proceed to shoot 18"+ groups at 15 yards with projectiles barely moving 200 FPS downrange. Carefully watching projectiles spin off far left and right every few shots... Finish up shooting ten magazines half filled; pack up, and drive off to enjoy a double non-fat soy half-caf pumpkin spice latte with triple foam no nutmeg at any one of the 350 Starbucks nearby. Do they have signs on the wall telling you "one or two pumps ONLY for variable pump air rifles" too? Never underestimate the amount of stupid in NY.

In short.... I still have absolutely no clue know what the laws are regarding this kind of device, even after some basic research. Certainly not going to call up the New York State Police SAFE Act hotline and start asking questions... 

[DNP]

Wow. (Extra emphasis added as that’s said by a Californian)

[Lane]

I found this statement on a website in reference to air gun laws specifically: "New York law prohibits any person under the age of sixteen from possessing any air-gun, spring-gun or other instrument or weapon in which the propelling force is a spring or air. --- New York has no other law governing non-powder guns."

The problem with this is: first and foremost; you can't believe everything you read on the internet. I don't know what I do not know. How could I; as a citizen of NYS know that there are no other laws governing non-powder guns (without reading every single law)? If ignorance of the law is no excuse; how would that protect me from an overzealous law enforcer? 

Essentially; that means I'm probably in the clear here to do whatever I want. But even finding that little tidbit of information wasn't easy. 

Does this also mean that if I use compressed hydrogen explosions with electric ignition that I could avoid all firearms laws (non-powder gun after all)?

[jtallen83]

44 minutes ago, Lane said:

Does this also mean that if I use compressed hydrogen explosions with electric ignition that I could avoid all firearms laws (non-powder gun after all)?

Potato guns don't seem to be an issue, that's high tech for me 

[Lane]

1 minute ago, jtallen83 said:

Potato guns don't seem to be an issue, that's high tech for me 

I love the idea of this; and shot potatos a good bit growing up. Being a bit older now; I'm less inclined to trust PVC pipe with my life. Maybe I'll get "bored" this winter though and weld up some failed exhaust components and build one from metal though...

Pretty happy with the Can Cannon running on junk .223 brass. Tiny powder charges make it really cheap. I even used it to fire anything I had primed with a wonky looking primer seating; even the mangled primers worked fine in those blank reloads.

[DNP]

For your next project, a hydrogen gas gun. I once knew a rocket scientist developing a gun to fire satellites into space. I only got to see a bar napkin sketch of how it worked, but but the gas fired a piston that compressed air and the compressed air fired the projectile. Granted they were working with a gun the size of a small airfield, they were launching a watermelon seed shaped projectile at Mach 6-7. They were aiming to hit 9. Don’t quote me on the numbers…it’s been many years since I got this info.  And it being on a bar napkin, there was likely alcohol involved. 

[Lane]

2 minutes ago, DNP said:

I once knew a rocket scientist developing a gun to fire satellites into space.

This is actually pretty common fodder for low level physics classes in college. Doing homework, or test problems on launching something into space with ________; fill in the blank.

[jtallen83]

40 minutes ago, Lane said:

low level physics

[DNP]

1 hour ago, Lane said:

This is actually pretty common fodder for low level physics classes in college. Doing homework, or test problems on launching something into space with ________; fill in the blank.

Well, fancy it up as much as you’d like…I’m not looking for it to launch anything into space. I want it AR sized and capable of taking decent sized game. Fired by a gas a little more commonly available would be nice as well. No more derail. Back to wizardry. 

[Lane]

9 minutes ago, DNP said:

Fired by a gas a little more commonly available would be nice as well.

If the hydrogen is a liquid it doesn't fall under any of the rules I've seen. I'd say rocket "rock chuck killer" is totally legal in hand size and rifle for all 50 states; if I didn't read that provision incorrectly. I'm not a lawyer, but it seems like rocket fueled projectile guns are good to go.

[Lane]

I'm going to derail my own thread briefly after the other night... Thanks @DNP I've been half wondering about this for a while.

On 9/15/2021 at 9:36 PM, DNP said:

For your next project, a hydrogen gas gun

Think I can have a functional prototype in a few days. The only thing I'm trying to think through at the moment is how to seal a projectile well enough to maintain a gas tight seal, and still have a launch and not a pipe bomb. In an ideal world the whole system could be evacuated to a reasonable vacuum, and then filled up with a gas fuel. 

Quite frankly; I have no idea how much power can be crammed into a small cannon with this method. I've realized I should be able to do some reasonably "safe" tests with 12oz cans though. I'm currently curious how oxy-hydrogen settles anyway. My initial assumption is it is reasonably well separated; with the hydrogen at the top of the storage vessel. I think the quick and dirty plan will be to stack beer cans upside down in the vacuum chamber (empty) and evacuate the vessel. Then attach a bag of oxy-hydrogen gas to the intake, and open the valve slowly. That should fill all the cans reasonably with the gas, then I can quickly seal the mouth without inversion; around the existing partial seal that has two electrodes in it. 

So.... That worked, and my ears are still ringing from it. I placed the test can in a small cardboard box, and hooked up a high voltage generator to arc across the wires inside the can. The can shot up about 20 feet which is impressive for a completely empty aluminum can; and the cardboard box exploded as well. Plenty of power in 12 oz of uncompressed gas. I got the gas from a pair of generators that I use for a torch once in a while. Those devices actually run at some pressure; so it's certainly possible to cram the same amount of gas in a smaller volume. Don't see that happening with the can tests, but that first successful test was enough to give me hope that this could actually bear fruit (and likely faster than my other build). 

[Lane]

Attached two videos of later testing, seems like you have to download to watch them. All the cans were made in the same vacuum chamber, but I can't swear to gas mix or leakage for any of them. 

Also shot the video in slow-mo; so they seem to play in slow motion with slowed down sound as well.

Pretty sure this would be a formidable option with on the fly gas generation (and higher pressures), perhaps a rather unique build based on what I've seen so far. It's difficult to find any real data about this; most people that mess with it are seeking out some kind of free energy. 

[Lane]

Seems like there's a glitch with the forum. I tried to edit the last post because the videos didn't seem to work. In edit mode; they showed video players. But I was too late to try an updated post. These links should work for those videos; for at least a day or two.

https://file.io/PS7aFobIC72A

https://file.io/d55oCTUDvE9V

[DNP]

Whoa whoa whoa…focus man. That was “next project”. Don’t stray from the current fun. All of this is way too much fun to watch though. You are a gifted man. 

[Lane]

15 minutes ago, DNP said:

That was “next project”.

This goes BOOM!

It is also the same trigger method I'm using in the lightning build (for trigatrons). Might have to run these builds side-by-side actually. The hydrogen fuel is working right out of the gate. Love the fact that it's just LOUD!

Not sure I'd trust it in a carbon fiber barrel. Only one way to find out though...

Don't forget to wear your safety glasses every time.

[DNP]

Lol. I wish we lived closer. I’d pay good money just to sit on the sidelines and watch the shenanigans. 

[Lane]

I presented the recipe.

NY and CA are almost the same place if you live in America. Only a few gas station fill ups between us; just drive and drive and drive. Heard there was shooting fun in Nov. I'm working towards a sick trunk full of LOL. NY style.

[DNP]

There is some fun in Nov and I’ve heard flights are cheap right now. Come west. 

[Lane]

Figured it was about time to circle back. I enjoyed the brief experiments into hydrogen combustion as a propellant option. What I found out in the process; is that it's actually rather common, and used in some extreme high power applications. There was even some talk years back about using it as a way to launch building materials into space. The appropriate search term for such things is "light-gas gun", or "combustion light-gas gun" depending on the details. 

What I was most surprised by, is that light-gas guns have evolved into two stage affairs for the most part. Here is a quick write up of that which used to be hosted by the NASA Ames Research Center: https://space.nss.org/settlement/nasa/Nowicki/SPBI108.HTM That diagram is shown below. There is in fact no combustion of the hydrogen, it is simply used as a compressed gas to increase the speed of sound in the medium; thus allow for faster projectiles. 

-----------------------------------------------

There are a few things holding me back on the lighting gun build at the moment. First and foremost would be: finish reading technical documents (bunch of PDFs) posted a few days ago, and then doing a bunch more math to solidify my coil designs. All my work up to this point was running estimates to fit the rough design parameters. Now that I've modified the projectile shape a few more times; and perhaps material, I need to revisit all those calculations with a bit more precisions. Measurements of the appropriate coil length (number of turns per layer) is now possible. Then trying to maximize efficiency (number of coil layers, spacing, etc.); and then ensure that appropriate potting method will hold up under voltage as well as compression pressure that happens during firing.

A few posts back there were a bunch of images of chemical options posted. The Super Corona Dope has the highest dielectric rating of anything, but it happens to be a varnish. I'm not at all sure how that would work for fully potting a coil. I'm a bit frustrated that I can't try it out for "cheap" either. A 2 fl oz jar is $20; and 33 fl oz is a little less than $80 shipped to my door. Seems like a huge waste to buy 2 oz and find out it will actually work for fully potting. On the other hand. If I can only use it as a thin coating; then I'll still need the epoxy potting material I would still be around the same $80 total. I MIGHT know someone with a jar of Corona Dope from yesteryear and that would certainly help in determining which way to go.

Finally; I need to get the lathe out and start turning a handful of projectiles in steel and aluminum. Unfortunately I can't get that kind of dirty until I get some other work out of the way around here. There is still an outstanding question about induction vs. reluctance that I won't really be able to answer without hands on testing. I can use old or junk coils for that work; but I still need a bunch of projectiles to see which way I ultimately need to go. That may also impact some of the minor details in coil designs as well, so; everything needs to happen in order. I do already have a number of fairly large induction drive units; so testing can happen when I get to that point.

[DNP]

Remember the low level physics grade rocket scientist I mentioned?  They built one of those the size of a small airfield…for launching xxxx into space. However, they still needed to increase the speed. That projectile they were launching was the size of a train car. 

[DNP]

His name is mentioned in your article. John Hunter. Congressman Duncan Hunter’s (Sr.) brother. 

[Lane]

4 hours ago, DNP said:

Remember the low level physics grade rocket scientist I mentioned?

The low level physics comment was in fact my personal experience. The point of doing those math problems at a low level is to (hopefully) show the student that just kicking a ball into space, or even trying to shoot it out of a gun is extremely difficult in terms of energy required. And that's only part of the story... The accelerations required are such that it can be difficult to keep things from being torn apart in the process as well. The same reason a light gas gun was only specified to launch building materials; human meat bags are totally out of the question.

4 hours ago, DNP said:

His name is mentioned in your article. John Hunter.

I tried to get a copy of the paper referenced on the previous link: "A Light Gas Gun System for Launching Building Material into Low Earth Orbit", but I could not find a copy that didn't require me to pay for it. Would simply visit a university library for something like that (even today); but I'm not even sure visitors are currently allowed. Before COVID I wouldn't have thought twice about dropping by for an afternoon of light reading, or browsing the journal archives.

What I did find online was a nice breakdown from UTRON Inc. that details the history of some of John Hunter's work. It talks about both the earlier "Two Stage Light Gas Guns" (bottom of page 6-7), as well as "Jules Verne Launcher" (bottom of page 10-11). The latter is the larger 1.52 km barrel length with hydrogen side injection. 

The second attachment is a PowerPoint slideshow with some details about the UTRON Inc. combustion light gas gun which apparently functions. 

All in all; this was a fascinating distraction that made me explore some other work I wasn't fully aware of. One note in the first PDF that applies to the lightning gun: "Large coilguns theoretically require very high voltage operation and very fast switching". That's been pretty clear to me since the beginning here; hence the reason I'm chasing reliable means of controlled arc discharge. I didn't see a lot of other options that made sense economically or performance-wise. Some ideal parameters would be, electrodes that don't change in shape over time after repeated use, and a reliable delay between trigger operation and magnetic field peak in the acceleration coil. In the event of induction operation, it appears the same system could be left undamped, and ring enough to provide A/C drive.

STA-witherspoonOct2000.pdf 6349KruczynskiDavid.pdf

[Lane]

Been bouncing back and forth in my mind between the magnetic accelerator, and and some kind of combustion light gas gun. 

Made some decisions about which way to go on the lightning gun build, and acquired a few more parts. High voltage generators around 20kV, and some standard Corona Dope which is just a few hundred V/mil lower in breakdown voltage than the Super Corona Dope. I figured if I design for the lesser, using Super Corona Dope later would be even safer. I've never gotten a thick MSDS in the mail with a chemical before (usually have to download my own). This one is pretty serious though; really love working with mutagens.

The last thing that appears to be missing here is a high voltage probe so I can actually measure the voltages I'm working with (for both design constraints and safety purposes), as well as use a scope to watch the timing of the same very high voltages. 

Looked at some brief napkin calculations for the combustion light gas gun. It seems like it wouldn't be terribly difficult to get rifle projectile energy out of a rifle sized package. The gas volumes required are small enough to work around one way or another. The really tricky part here is the unpressurized autoignition temperature of around 1,000F. Still not sure exactly how much that changes under compression, or what I can get away with in the real world. 

Did the first laser cutting on glass tubes in the rotary. Confining a spark inside one with open ends is LOUD (spark gap is easily 15mm long). I'm going to seal them when I install the other electrodes, but I'm quite certain they won't be silent. Looking forward to hooking things back up for a controlled discharge into the original high current red acceleration coil. Shouldn't take long to knock out some plug ends for the electrodes to mount to, and seal them up. The other circuit plugs into the same glass tube, using it as a switch to fire the coil. The capacitor charge rides the lightning from the HV discharge inside the tube, firing a short pulse to the acceleration coil. 

This is starting to look like fun again. 

[DNP]

Just don’t feed that stuff to the bats…we got enough Corona issues around here. And dope tends to be a gateway drug. 

Edited September 27, 2021 by DNP

[Lane]

On 9/27/2021 at 1:07 AM, DNP said:

Just don’t feed that stuff to the bats…we got enough Corona issues around here. And dope tends to be a gateway drug. 

Feed it? You don't even need to go half that distance. A little sniff, or wiping it on your hands is a pretty good start. Was a lot more curious myself what kind of heritable mutations might be considered useful these days for humans. The MSDS doesn't say shiit about bat mutations; I assume it's only a problem for humans. 

Just doing a little more CAD sketching on this project. I've realized pretty quick that I'm only going to be able to have "fun" with this if I split things off now. There is no way the original design is going to do too much. Reading a lot more research from the 80s, 90s, and beyond has me pretty well sold on induction drive anyway. No contest in terms of efficiency; and it's a good primer for some other things I've been ignoring around here lately.

What I want to be able to reproduce first; is the Trigatron firing of a ferromagnetic projectile, and ones of aluminum, and copper. With the same design shown in the video in the first post of this thread. I understand how that works, and the difference between steel and aluminum is what has me still wondering... That was a big part of starting this quest. 

I'll post up a bunch more research next time around. Still reading a lot of prior work to help (hopefully) avoid wasting time and resources on things I already know aren't great in terms of overall efficiency. At the same time. I want to test all my initial projectiles and coils as a baseline for corona discharge switching. Nothing wasted.