Search found 187 matches

by Skywalker
Mon Sep 07, 2020 12:11 am
Forum: Pneumatic Cannons
Topic: Supersonic baseball cannon on 'Smarter Every Day'
Replies: 2
Views: 378

Supersonic baseball cannon on 'Smarter Every Day'

They built a balanced piston valve. Very heavy-duty steel, they've run it as high as 500psi. The barrel is evacuated before the shot. There's a nice shadowgraph image of the shock wave from the supersonic baseball. Discussion of the concept: https://youtu.be/E60G3ba4TUA?t=296 The shock waves start h...
by Skywalker
Sun Mar 22, 2020 12:25 pm
Forum: BB, Airsoft, and Pellet Guns
Topic: Shock absorber spring rifle?
Replies: 2
Views: 831

Shock absorber spring rifle?

I bet a motorcycle or automotive shock absorber could be turned into a wicked spring rifle... might be on the dangerous side tho! Inspired by seeing one in the dumpster the other day.
by Skywalker
Sat Nov 02, 2019 10:57 am
Forum: Hybrid Cannons
Topic: Two-stage hybrid
Replies: 32
Views: 6604

Re: Two-stage hybrid

Interesting concept, me gusta! The trouble with conventional dieseling spring-guns is the variability of the ignition timing due to fuel mix, which can damage the piston and cause unstable muzzle velocity. Having the ignition occur at a fixed compression could help solve those problems. Metering the...
by Skywalker
Tue Apr 09, 2019 11:19 pm
Forum: Hybrid Cannons
Topic: Cooking up a little something...
Replies: 79
Views: 14517

Re: Cooking up a little something...

Damn, that's impressive looking even in CAD. I'm looking forward to the IRL version! Go big or go home, eh? :D
by Skywalker
Tue Apr 09, 2019 8:00 pm
Forum: Hybrid Cannons
Topic: Autonomous hybrid caliber .25 Prototype 3
Replies: 16
Views: 4101

Re: Autonomous hybrid caliber .25 Prototype 3

Very nice work! I would copy this design if I had the space & time to work on airguns again.

What style of valve is used? Any progress on the pump?
Edit: Ok, I have read the latest thread now and I understand the gun. Very cool.
by Skywalker
Tue Apr 09, 2019 8:43 am
Forum: Pneumatic Cannons
Topic: Balanced Hammer Valves
Replies: 19
Views: 3272

Re: Balanced Hammer Valves

I'd been ignoring friction for the most part. Friction isn't an entirely bad thing for this design, though: the valve-pusher cylinder should *not* travel with the poppet valve -- it needs to stay behind so that the poppet unseats. The whole train of (hammer --> breach slide --> valve pusher --> popp...
by Skywalker
Mon Apr 08, 2019 10:06 pm
Forum: Pneumatic Cannons
Topic: Supersonic peashooter
Replies: 5
Views: 1227

Re: Supersonic peashooter

Edit: Anatine, I didn't read your response before posting! You scooped me, haha! :oops: Hydrogen would definitely help, although it would be a waste to use it this way without igniting it. :D Dieseling the air gun would definitely help get the energy up -- I've been thinking about how to construct a...
by Skywalker
Mon Apr 08, 2019 8:47 pm
Forum: Pneumatic Cannons
Topic: Balanced Hammer Valves
Replies: 19
Views: 3272

Re: Balanced Hammer Valves

Interesting -- so it's a dump valve, though. Looks to me like the unbalanced force is going to blast it open and keep it that way, just like the QDV. I sketched up an idea for a balanced version of the AirForce Condor. The basic idea is to transfer the hammer strike through a movable cylinder to the...
by Skywalker
Sun Apr 07, 2019 1:02 pm
Forum: Pneumatic Cannons
Topic: Balanced Hammer Valves
Replies: 19
Views: 3272

Re: Balanced Hammer Valves

These are cool, but can they be re-arranged to look more like the typical piston gun, where the porting is full-bore straight into the breach? I guess you'd need an awkward hammer that pulls, rather than pushes, the stem.
by Skywalker
Sun Mar 31, 2019 3:56 pm
Forum: Pneumatic Cannons
Topic: Supersonic peashooter
Replies: 5
Views: 1227

Supersonic peashooter

I'm thinking about ways to make a self-contained gun where the energy to fire it is delivered manually by pulling a more-or-less constant force across a moderate distance (3 feet). Supposing I can lift about 50lb, and suppose I can make the 'stacking curve' sufficiently flat that I deliver 80% of th...
by Skywalker
Wed Aug 31, 2016 7:30 am
Forum: General How-To & Discussion
Topic: Is spudding dead?
Replies: 102
Views: 28265

Re: Is spudding dead?

Hey guys! It's been ages since I logged on [edit: almost 4 years!]. I still keep my cannons at my parent's garage, but I've lived in apartments in the city for the last 6+ years, so I haven't been able to build anything new. I don't foresee that changing for a long time either, unfortunately. It's a...
by Skywalker
Mon Jul 22, 2013 11:15 pm
Forum: Off-Topic Hobbies
Topic: Combustion Water Bottle Rockets
Replies: 33
Views: 4143

I used to do this with oxygen and gasoline or acetylene, no water. I was crazy enough to put some lead fishing weights or washers on top, along with fins and a nosecone. I'd say I got 300+ feet, but that may be generous. No idea how high the weights (read: shrapnel) went when the bottle exploded, wh...
by Skywalker
Sat Jun 01, 2013 9:32 am
Forum: SpudFiles Discussion
Topic: SF is dying
Replies: 71
Views: 7030

I'm at school in the middle of a city, with a smallish apartment and no car. I don't have the space or the time right now to build anything. I'm sure I'll pick the hobby up again at some point in my life though. I'm consoling myself by building some water bottle rockets this summer. Oh, and when I v...
by Skywalker
Wed Jan 02, 2013 10:49 pm
Forum: Hybrid Cannons
Topic: Cartridge hybrid build log
Replies: 22
Views: 4686

Edit: I want to move this to the showcase. Should I start another thread or can a mod copy the thread over? It's a bit louder at 10x, but still nothing like a .22 rifle. Unfortunately the epoxy around the schrader valve cracked & there's a slight leak now in the cartridge. I'll have to rethink my de...
by Skywalker
Tue Jan 01, 2013 8:21 pm
Forum: Hybrid Cannons
Topic: Cartridge hybrid build log
Replies: 22
Views: 4686

I added the piezo trigger on the handle, you can see it in the video. The video shows the ignition system, the bolt action operation, and firing / damage. It's done at 5x. http://www.flickr.com/photos/57841472@N05/8336111558/ I had to reduce the burst disk thickness to one layer of paper & one layer...