Author Topic: Project Fury 20mm BIGbore. 3100FPE! (Read 86361 times - 2 votes)
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MJP · « **Reply #480 on:** July 28, 2022, 03:45:07 PM »

Quote from: subscriber on July 28, 2022, 06:43:58 AM

Thanks Marko,

The brake is a thing of beauty. Looks like it directs the air backwards by a few degrees, for more recoil reduction than just rocket effect cancellation.

Do you have an equivalent recoil to compare it to? Something like a 1.25 ounce 12 gauge slug at 1600 FPS, shot from a 7 lb shotgun.

I presume you have to use good hearing protection to shoot this thing.

It's loud, recoil is different from powder burners it's longer. But intensity is worse than Barret 50cal

Marko

Insanity · « **Reply #481 on:** July 28, 2022, 04:33:46 PM »

Marco what 3D printer was used to print the brake?

MJP · « **Reply #482 on:** July 28, 2022, 05:34:35 PM »

Markforge before they forbid to print any parts of guns.

Marko

Rob M · « **Reply #483 on:** July 28, 2022, 08:14:43 PM »

those printers run about 1/2 a million dollars.

rsterne · « **Reply #484 on:** July 29, 2022, 12:51:02 AM »

Impressive, that is more than double the tensile of most stainless steel (304 is only 515 mPA), and the same as heat treated 17-4PH H900 bar stock.... I had no idea that printed metal was the same strength as solid....

Bob

subscriber · « **Reply #485 on:** July 29, 2022, 08:05:38 AM »

Marko,

I hope this does not highjack your thread:

As commercial 3D printers don't allow orders for "gun parts", perhaps there is a way to make another version or copy of your muzzle brake. The images below are for a 20 mm diameter projectile, using a 2 mm radial clearance (arbitrary):

The brake is fabricated from individually machined baffles, that locate in grooves, and are welded to the top and bottom cover plates. I used 5 plug welds per baffle per side, but that could be increased.

The parts can also be brazed together. Then the plug weld holes would be left out. Either way, a mandrel would be used to keep the baffles coaxial while welding, or brazing. After rounding the OD as shown in the bottom images, the baffles could be line bored to final size, if the mandrel arrangement was not satisfactory.

The baffles start life on a lathe, machined front and rear. Then flats are milled, top and bottom. The cover plates are milled, with tapering holes for the plug welds to attach to the baffles.

The rear baffle has a split spigot to form a "collet" that is a snug fit on the front of the barrel. Rather than complicate the rear baffle part by machining in or welding on the clamping screw support structure, I just selected a stock industrial hose clamp to close the collet against the barrel. Four slots are arbitrary, chose for machining simplicity and adequate flexibility.

The shape of the baffle curvature is arbitrary, although I tried to model it on your brake by rough visual scaling. This curve could be simplified for manual lathe machining, if a CNC lathe is not available. A large form tool could be made and used, although that seems like not a friendly machining job. Using a rotary table on a mill may be easier, and enable ball nose cutters to approximate the desired baffle face curvature.

The last images show how the welded assembly could be rounded in a lathe to reduce unnecessary mass.

The attached ZIP file contains the the assembly with all part in STEP file format. Both as welded; and as the version after rounding in a lathe (nicer looking).

Anyway, I did this purely as food for thought, in case you wanted more brakes with your flow design, or different ones. And, as you stated, the design cannot be CNC machined in one piece. So, if you can't print them anymore; how can they be made? Like this.

I could adapt this design to bolt together, but would need to make the baffles thicker in places to accommodate the bolts.

subscriber · « **Reply #486 on:** July 29, 2022, 08:15:05 AM »

Forgot to attache an image of the lathe turned precursor baffle shape; before the flats are milled. This precursor part could be milled using a rotary table, in place of a lathe:

MJP · « **Reply #487 on:** July 30, 2022, 03:56:13 AM »

That just shows how much the 3D printing changes the way manufacturing industry is evolving right now.
Shapes that are not possible or cost effective to make are a reality today.
Let's not go in to this subject more in this thread.

I have some small upgrades planned for chamber sealing, having some blow by from the bolt. Seems that the lip type seal needs a backing ring.

Marko

MJP · « **Reply #488 on:** August 10, 2022, 04:23:12 PM »

We pushed the boundaries of airguns in to the new level. Air helium mix, and there is a lot of recoil and I seriously mean alot!

5966J / 4400fpe on 310bar, very limit nearing the valve lock.
It's insane, and nothing holds together for too long. More info coming when we get all the pictures and videos sorted.
Bruised and happy ish, so close to 6kJ... one day.

Marko

Insanity · « **Reply #489 on:** August 10, 2022, 04:36:34 PM »

Very impressive!

rsterne · « **Reply #490 on:** August 10, 2022, 04:53:01 PM »

W O W !!!!

Bob

rsterne · « **Reply #491 on:** August 10, 2022, 05:07:33 PM »

Just went back and looked up the numbers on the barrel.... If they haven't changed, the bore is 0.807" and the length is 43.3", for a bore volume of 22.14 CI.... At 310 bar (4500 psi) the maximum possible FPE (including all losses), if the pressure remained constant, and including the energy to accelerate the air/helium, would be 8300 FPE.... On air, my "lofty goal" would be half that (4150 FPE), and you are beating that with an air/helium mix.... Getting to 3016 FPE on 300 bar of air is nearly 38% of the maximum, which is a fabulous achievement with such a colossus, IMO.... Congratulations, Marko !!!!

My guess is that on pure Helium, you will pass that 6,000J goal quite easily....

Bob

oldpro · « **Reply #492 on:** August 10, 2022, 05:34:57 PM »

Wow ,,,,,Legend status achieved....

MJP · « **Reply #493 on:** August 10, 2022, 05:52:16 PM »

Thanks guys,
It's been quite the journey, set out to make something different and not in my wildest dreams excepted t to achieve so much power from an airgun.
It's actually more accurate than I imagined but it takes way more to handle than I honestly am capable shot after shot.

It will rough you up pretty good every time pulling the trigger. 2-3 shots is somewhat manageable but after that it's starting to get painful and less accurate.
Will post video when a friend gets them edited and pictures in a day or so.
There is something different with 95 gram projectile going past supersonic, like thunder in the air as it rips the sound barrier.

Valve broke twice today, first time it stuck flat out open, I can assure it hurts. Very violent ordeal. Second time the balancer just started leaking and we got one shot on two 5L waterjugs to finish it off and end the day. Just leaking and no drama.

Marko

rsterne · « **Reply #494 on:** August 10, 2022, 06:24:48 PM »

OUCH !!!!.... I know what a tank dump is like on a 200 FPE airgun, I can only imagine!!!!.... Regardless of how much energy ends up in the bullet, your shoulder is probably feeling the recoil from 7000-8000 FPE every time you squeeze the trigger.... Maybe more if the valve is open until after the bullet exits the muzzle (which is likely)....

Bob

sb327 · « **Reply #495 on:** August 10, 2022, 09:23:00 PM »

Mercy! I have had a valve dump with a Texan before and it was quite alarming. I can’t imagine what that beast your working with would be like.

Excellent work!

Dave

Rob M · « **Reply #496 on:** August 10, 2022, 09:38:41 PM »

4400 fpe , i dont think we will see that from crosman any time soon.. congrats Marko.

JuryRigger · « **Reply #497 on:** August 13, 2022, 12:05:07 AM »

I had to look up a rifle cartridge power chart to really get a grasp on just what 4400+ FPE means; short of it being 209 times more than my pop-gun Diana 350 pushes in a shot...
HOLY TOLEDO!....You're only in the same power category as the .338 Lapua Magnum....

Congratulations on your amazing achievement; I can scarcely even begin to comprehend that kind of energy...
Perhaps it's time to consider a turret mount?...

Jesse

MJP · « **Reply #498 on:** August 13, 2022, 08:51:13 AM »

Thanks guys,

That was an excellent point with the recoil Bob, didn't think about the airmass and it's affecting recoil.

Yes 338 lapua is similar on energy but the momentum of the projectile is dwarfed by the 20mm slug. Can hit steel with .338 and it makes a ringing sound and swinging some.

Hit it with the 130 gram projectile and you'll be searching the plate from the range and sometimes from pretty far.
8mm 200mm round plate flys 20-40m depending on the rigging. Usually a conveyor belt or car timing belt.

Not going to push this much more, the forces are starting to be more than the materials and O rings can handle dynamic load.
Starting to be material choices like Nasa shuttles. fiber reinforced PEEK, 7075, 42crmo4, GR5 titanium and molybdenum ceramic friction reduction coatings.

FEM analysis starting to be a must on design and material choices. So don't try this at home, if you don't know what you are doing.

Valve parts have a short lifespan, I don't think the Peek seal lasts more than 200-300 shots, and O rings less than that.
Just something to think about.

Marko
Edit: couple of pictures

rsterne · « **Reply #499 on:** August 13, 2022, 12:39:26 PM »

How far can the LabRadar track those massive slugs?....

Yes, at the power levels you are running, the air mass will be approaching the slug mass.... That is one of the reasons 50% of maximum is so difficult to achieve.... but easier with heavy slugs travelling slowly.... It is also the main reason that Helium can increase the performance, it only has 1/7th the density of air, so for the same push (pressure), there is much less gas mass to accelerate, and more of the energy goes into the bullet....

Bob

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Project Fury 20mm BIGbore. 3100FPE!

Author Topic: Project Fury 20mm BIGbore. 3100FPE! (Read 86361 times - 2 votes) )

Author Topic: Project Fury 20mm BIGbore. 3100FPE! (Read 86361 times - 2 votes)
)