Search found 33 matches

by Pennywise
Mon Nov 18, 2024 6:44 pm
Forum: Hybrid Cannons
Topic: Mon blue king cal 68
Replies: 16
Views: 2909

Re: Mon blue king cal 68

Very cool! Any chance you have more photos of the inner workings of the gun?
Impressive results from "only" 11x!!
by Pennywise
Tue Nov 05, 2024 11:40 am
Forum: BB, Airsoft, and Pellet Guns
Topic: I got a 3D printer
Replies: 10
Views: 1581

Re: I got a 3D printer

What i need next is to find is a precision 3d scanner. What i mean by that is i need to FIND one. Like laying on the ground. My wallet is already emaciated from these hobbies. I found an app that does a 'fair' job of this, letting me take a scan of the frame of this gun, and turning that scan into a...
by Pennywise
Tue Nov 05, 2024 10:39 am
Forum: BB, Airsoft, and Pellet Guns
Topic: I got a 3D printer
Replies: 10
Views: 1581

Re: I got a 3D printer

3d printers are wildly useful for these projects. Obviously not all parts can be made from printable plastics, but I can't tell you how many times I've had to print a specialized mount so I could put an irregular object in my mill vice. This is the current project. Internals are 304 stainless. 3d pr...
by Pennywise
Sat Mar 30, 2024 4:16 pm
Forum: Hybrid Cannons
Topic: Hybrid velocity
Replies: 20
Views: 26239

Re: Hybrid velocity

Yeah I noticed the multi-piece design, I was just wondering if the air hitting it broadside at ~6000mph would vaporize it. Though thinking if it now, if it can withstand the gforces of the initial shot, that should have been obvious. I've been working through a design that wouldn't necessitate a sac...
by Pennywise
Sat Mar 30, 2024 2:37 pm
Forum: Hybrid Cannons
Topic: Hybrid velocity
Replies: 20
Views: 26239

Re: Hybrid velocity

Very interesting. At those velocities, does the sabot shatter on exit? I would be lying if I said I haven't been thinking of ways to pack a 2 stage gun into a rifle-esque design. Quinn, as I've said before, PLEASE post any picture/video/drawing of any of the guns you've built. I would LOVE to see th...
by Pennywise
Wed Mar 27, 2024 1:41 pm
Forum: Hybrid Cannons
Topic: Hybrid velocity
Replies: 20
Views: 26239

Re: Hybrid velocity

Quinn, please stop. D_Hall, I'll have to learn more about Maxwell-Boltzmann and related topics, thanks. I may be at the upper limits of what can be accomplished with propane, in that case. Given your reasoning for the velocity potential with powder, it would stand to reason that hydrogen/oxygen woul...
by Pennywise
Tue Mar 26, 2024 10:01 am
Forum: Hybrid Cannons
Topic: Hybrid velocity
Replies: 20
Views: 26239

Re: Hybrid velocity

What are methods of passing beyond the local SOS? I imagine things like raising temperature beyond that of standard combustion or using a fuel whose combustion produces elements with higher SOS, but these are both modifying the SOS limit rather than surpassing that limit. The ~3400fps lines up with ...
by Pennywise
Sun Mar 24, 2024 9:37 am
Forum: Hybrid Cannons
Topic: Hybrid velocity
Replies: 20
Views: 26239

Re: Hybrid velocity

Are the expanding gasses in a hybrid not limited to local SOS like the released pressure in a pneumatic is?
by Pennywise
Mon Mar 18, 2024 7:07 pm
Forum: Hybrid Cannons
Topic: Hybrid velocity
Replies: 20
Views: 26239

Hybrid velocity

I have measured upwards of 3355 feet per second with a hybrid I've been working on. Mind you, I'm using a .510" diameter 3d printed 100% infill aerodynamic projectile weighing very little. I highly doubt this is the projectile velocity, and instead is catching debris or even the gasses themselves .....
by Pennywise
Wed Feb 21, 2024 6:54 pm
Forum: Pneumatic Cannons
Topic: this my 100th post yay
Replies: 31
Views: 15977

Re: this my 100th post yay

There is a sticky in the Spudfiles general forum about exactly this.
by Pennywise
Thu Feb 15, 2024 8:23 pm
Forum: Pneumatic Cannons
Topic: this my 100th post yay
Replies: 31
Views: 15977

Re: this my 100th post yay

Or a picture/drawing of your pneumatic whose chamber exhibits no pressure loss from each shot.
by Pennywise
Thu Feb 15, 2024 12:47 pm
Forum: Hybrid Cannons
Topic: do any of you guys have some tips for hybrids
Replies: 3
Views: 4694

Re: do any of you guys have some tips for hybrids

Are you just refusing to read ANY of the 'stickies' or previous posts before making all of these threads?
by Pennywise
Tue Feb 13, 2024 12:09 pm
Forum: Combustion Cannons
Topic: Combustion cannons
Replies: 2
Views: 6951

Re: Combustion cannons

Assuming you mean PETN/ETN. Discussion of the use of explosives is not allowed on these forums, to my knowledge. Also, given the level of knowledge you have shown in your multitude of questions on this forum, I'd STRONGLY recommend you do not attempt to utilize this material.
by Pennywise
Tue Feb 13, 2024 12:02 pm
Forum: Combustion Cannons
Topic: pnumatic spud guns
Replies: 11
Views: 11749

Re: pnumatic spud guns

There is no way to use pressurized air as the energy source and not observe the pressure drop after use. An efficient system may be able to lessen the pressure loss, but it is impossible to eliminate it unless the pressure isn't what's being used as the primary propellant. Many people have used pcp ...
by Pennywise
Wed Nov 29, 2023 4:16 pm
Forum: Hybrid Cannons
Topic: Hybrid disk burst pressure effect on performance
Replies: 23
Views: 104834

Re: Hybrid disk burst pressure effect on performance

Correct me if this theory is flawed, but could it be more than simply the effective chamber being larger? The unburnt portion of the fuel has mass to it, and so as it's being propelled by the expansion of the burning fuel behind it, it pushes the projectile faster and faster. As the flame front catc...