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...

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.

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...

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 ...

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.

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

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

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).

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.

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...

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 ...

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...

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.

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

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...