To get more specific, static friction matters when the projectile mass is low (like with Nerf darts) because it allows the pressure to build up before the projectile moves. If the projectile mass is low, then the projectile might move a lot initially, which would keep pressure lower for the duration...

There definitely are a lot of bots on SpudFiles, though few seem to be posting anything at this point. They seem to mostly be accessing the forum, slowing it down a lot if not bringing it down entirely over the past few days. PCGUY, I'd recommend blocking many of the worse behaving bots with robots....

Thanks for making the new tool. I haven't had much of a chance to look at it yet, but I wanted to make a quick comment as SpudFiles has been down more often than not lately. On that note, it might be worth putting some contact information in the spreadsheet itself so that you're not so reliant on Sp...

You can definitely run JavaScript in a web browser locally without a web server. Many programs today also are written in JavaScript but basically embed an entire browser with the program, so the user doesn't notice that it's not native. I'm not so sure about WebAssembly. I think Chrome doesn't like ...

Good points. If you want something that doesn't require installing any extra software, JavaScript or WebAssembly would be better choices than a spreadsheet. It would be neat to have a webpage that does the simulation. It would be completely cross-platform. You could even run on your phone! It would ...

It's your choice, but I'd recommend against using a spreadsheet for anything nontrivial. Debugging and testing spreadsheets is far too difficult. Actual code is a much better option. I might make a prototype of something in a spreadsheet, but for any "production" software, code is a better choice. I...

https://docs.google.com/forms/d/1cd9N9VPBIBtLxRCRNrI1BYXyQaKlYbyiW5ZkRDAVtMw/viewform All, I haven't participated in this community for a while due to other time commitments. But I know there are a number of people who build water guns here, and I'm running a survey for one of my websites about what...

Nice work. What is GALE? I'm assuming it's a code you wrote, but I could be mistaken. How do the various codes compare against any measurements you've made? This sort of validation is really important if we want to understand how to make better launchers. I think if this comparison was done, you mig...

The professor replied back to my email: Ben, I have to admit that I have some of the same questions. We're in the process of doing a straight connector with no convergent section. I'm very eager to see what happens. Eventually, I'll need to do a CFD analysis as well. Mark So, it seems that we're on ...

I emailed the professor. I'll post any response I get. My email is below. Hello Prof. French, I am a graduate student working in computational fluid dynamics who is also interested in the internal ballistics of compressed gas guns. I recently saw you and your students' supersonic ping-pong ball gun ...

I didn't watch the video before. I watched most of it now, and I only saw one test. If anyone could point out specifically where they did an otherwise equivalent test (e.g., with the vacuum) without the nozzle, I'd be interested in knowing. It's also worth noting that the professor in the video says...

As I said in the off-topic thread, I am skeptical the converging-diverging nozzle helped here. They didn't do a test without it best I can tell, so there's no solid way to know if it helped. These nozzles are mainly used when the inlet air is extremely hot to convert the heat into gas kinetic energy...

I'm skeptical the convergent-divergent nozzle is necessarily helping here. They did no tests without it best I can tell. For all we know the gun would have performed better without it.

Also what could be worth considering is forming a design programme that is made entirely from experimental data, have you ever considered such an idea yourself? It is certainly possible and attractive for the reasons you detail. However, it would be difficult even for simple low-speed pneumatics if...

Your graph, have you tested + recorded (or similar) where an actual pressure reading of the system would be taken at? I wonder how close it would lie to the two lines. Also your equation it's perplexing me what law/scientist/rule/parrot you got it from, I will definitely use it in future but I like...