Search found 1893 matches

by D_Hall
Tue Nov 08, 2022 10:16 am
Forum: Ammo & Parts
Topic: Can you make a pneumatic cannon shoot snowballs?
Replies: 7
Views: 3562

Re: Can you make a pneumatic cannon shoot snowballs?

Yeah I thought about this too but it would have much more friction and sharp corners would make it unstable in flight. It possibly could even desintegrate in air. Friction for any reasonable projectile is negligible in the "does this thing even work" sense. As for unstable flight, you're going to h...
by D_Hall
Sun Nov 06, 2022 12:15 pm
Forum: Ammo & Parts
Topic: Can you make a pneumatic cannon shoot snowballs?
Replies: 7
Views: 3562

Re: Can you make a pneumatic cannon shoot snowballs?

A snow BALL might be difficult. But a snow cylinder would have the same effect and would be easy to put your foam pusher plate behind.
by D_Hall
Thu Jun 09, 2022 10:35 pm
Forum: Combustion Cannons
Topic: Spud gun disguised as classic artillery
Replies: 7
Views: 3674

Re: Spud gun disguised as classic artillery

The " percussion cap" you're using probably works as intended for it's intended use. However, you're trying to ignite a fuel air mixture and will need a hotter, faster spark. Also a mixing fan would help greatly to mix the fuel and air and to clear the chamber after shots. Use a gas grill igniter f...
by D_Hall
Mon Jun 06, 2022 10:42 pm
Forum: Combustion Cannons
Topic: Spud gun disguised as classic artillery
Replies: 7
Views: 3674

Re: Spud gun disguised as classic artillery

As far as I'm concerned.... If you're using hair spray or any other "aerosol" that isn't intended for burning, you've failed to do any meaningful research on the topic of spud guns. DITCH THE DAMNED "AEROSOL PROPELLANTS"! Propane. In a pinch, butane. If you find yourself in a 3rd world country with ...
by D_Hall
Tue Mar 08, 2022 11:46 pm
Forum: Off-Topic Hobbies
Topic: My current hobby: Cowboy Action Shooting
Replies: 17
Views: 15166

Re: My current hobby: Cowboy Action Shooting

And just for fun... I put together a video of the local club's shooters. I don't think there will be any Oscar nominations for this video, but it sure was fun making it.

by D_Hall
Sat Dec 18, 2021 8:40 pm
Forum: Off-Topic Hobbies
Topic: My current hobby: Cowboy Action Shooting
Replies: 17
Views: 15166

Re: My current hobby: Cowboy Action Shooting

And today my son had an impressive run.....

by D_Hall
Fri Dec 03, 2021 4:29 pm
Forum: Off-Topic Hobbies
Topic: My current hobby: Cowboy Action Shooting
Replies: 17
Views: 15166

Re: My current hobby: Cowboy Action Shooting

I realize there are people out there who are much faster than I am, but I was pretty proud of this run.....

by D_Hall
Fri May 28, 2021 8:33 pm
Forum: Off-Topic Hobbies
Topic: Two Italian WW2 helmets found
Replies: 5
Views: 5420

Re: Two Italian WW2 helmets found

I think you're lucky to live in a location with history. I'd love to do stuff like that but.... Well, there isn't really anything like that around here. Nobody lived here until WWII (and even then it wasn't a battleground).
by D_Hall
Fri May 28, 2021 1:06 am
Forum: Hybrid Cannons
Topic: Any official studies of Hybrid Cannons?
Replies: 8
Views: 6828

Re: Any official studies of Hybrid Cannons?

I remember a paper that went with that presentation, but now that I think about it.... That may not have been public release. Not sure.
by D_Hall
Sat May 22, 2021 4:46 pm
Forum: Hybrid Cannons
Topic: Any official studies of Hybrid Cannons?
Replies: 8
Views: 6828

Re: Any official studies of Hybrid Cannons?

This is one of the few examples I remember of a publicly available paper from Utron's contracted government research project for a "Combustion Light Gas Gun" (CLGG) - A.K.A. a badass hybrid that many strived here to get close to. Full paper here: https://apps.dtic.mil/sti/pdfs/ADA462130.pdf There i...
by D_Hall
Sun Nov 08, 2020 3:58 pm
Forum: Pneumatic Cannons
Topic: PVC Primer/Glue says DO NOT TEST WITH AIR
Replies: 8
Views: 4606

Re: PVC Primer/Glue says DO NOT TEST WITH AIR

I looked at the GGDT program and it doesn't appear to have an option to calculate the maximum range in which it will be able to fire which is in my opinion the whole point of the software.. The point of the program is to have an idea of what your muzzle velocity will be. As for maximum range, that ...
by D_Hall
Sun Jul 26, 2020 1:30 am
Forum: Pneumatic Cannons
Topic: Calculations related to pneumatic cannon.
Replies: 9
Views: 10259

Re: Calculations related to pneumatic cannon.

Probably the quickest/easiest hand calcs you can do for potato gun prediction.... EndPressure = StartPressure * ChamberVolume / (ChamberVolume + BarrelVolume) MuzzleEnergy = (StartPressure + EndPressure) / 2 * BarrelLength * PI/4 * BarrelBoreDiameter^2 MuzzleVelocity = sqrt (2 * MuzzleEnergy / Proje...
by D_Hall
Mon Jul 20, 2020 11:09 am
Forum: Off-Topic Hobbies
Topic: I'm not photographer but....
Replies: 4
Views: 6842

Re: I'm not photographer but....

Setup wasn't anything fancy.

Canon T-6 (about a five year old consumer level DSLR).

Comet pic was taken with a 70-300 zoom lens at...maybe 100 mm.

Milkyway pic was taken with a fixed 50 mm lens.

Decent tripod.

Not star trackers or telescopes in the normal sense of the word.
by D_Hall
Mon Jul 20, 2020 12:53 am
Forum: Off-Topic Hobbies
Topic: I'm not photographer but....
Replies: 4
Views: 6842

I'm not photographer but....

...I'm still pretty pleased with these two pics I took tonight.

Image

Image
by D_Hall
Wed Jul 01, 2020 5:50 pm
Forum: Ammo & Parts
Topic: Brass as the foundation of a projectile?
Replies: 6
Views: 6942

Brass as the foundation of a projectile?

I'm sitting here looking at a piece of 38 special brass. It just happens to be on my desk (yes, really). And I'm thinking to myself, "Self, this might make a good projectile." More to the point, I could see epoxying a nail in the primer pocket to make a dart. But a dart that is reasonably cheap/easy...