Search found 2239 matches

by Fnord
Sat Oct 24, 2015 11:20 am
Forum: Combustion Cannons
Topic: Noise cannon for RC planes
Replies: 162
Views: 23097

Re: Noise cannon for RC planes

Hi Futterama! Getting a machine-gun sound from a small combustion cannon is super simple, the only hard part is if you actually want it to shoot something! The most important question is... what's your payload capacity? It would save a lot of headaches if you could carry a small hpa tank. Where you ...
by Fnord
Tue Sep 22, 2015 11:02 am
Forum: Combustion Cannons
Topic: fuel question H2 O2 or Hair spray
Replies: 11
Views: 1786

Re: fuel question H2 O2 or Hair spray

Oxy hydrogen is the same thing as H2 + O2... You can make it from water. Any fuel mixed with *pure* oxygen instead of air needs to be used in a metal gun, not PVC. If you're having trouble understanding anything, I could simplify the description and run it through a translator (if you think it would...
by Fnord
Mon Sep 21, 2015 9:25 am
Forum: Combustion Cannons
Topic: fuel question H2 O2 or Hair spray
Replies: 11
Views: 1786

Re: fuel question H2 O2 or Hair spray

Hmm, lets see. On one hand we have a substance that's intended to keep your hair in shape, and on the other we have a substance which is liquified and used to launch rockets into space. We have a very detailed wiki page for this. http://www.spudfiles.com/spud_wiki/index.php?title=Common_Fuels_for_Co...
by Fnord
Thu Sep 17, 2015 9:57 am
Forum: Pneumatic Cannons
Topic: Gas travel distance& efficiency
Replies: 10
Views: 909

Re: Gas travel distance& efficiency

The second is less efficient but there may be exceptions to this rule. Because the gas accelerates to a significant velocity before it encounters the projectile, it will experience shock heating from the sudden recompression. With the right type of projectile, valve and barrel you can see some notic...
by Fnord
Tue Sep 08, 2015 7:44 pm
Forum: Pneumatic Cannons
Topic: Air Cannon Firing Mechanisms
Replies: 2
Views: 1782

Re: Air Cannon Firing Mechanisms

And pressure rated pipe to boot!
by Fnord
Mon Sep 07, 2015 10:24 am
Forum: General How-To & Discussion
Topic: Where's Jack?
Replies: 12
Views: 1704

Re: Where's Jack?

Oh there he is. Half life 3 confirmed?
by Fnord
Mon Aug 31, 2015 10:14 am
Forum: Combustion Cannons
Topic: worked twice now nothing
Replies: 5
Views: 1152

Re: worked twice now nothing

Post a picture of the gun and we'll be able to give you more reliable advice. To begin with, try starting fluid instead of gasoline. It vaporizes easily from an aerosol can, and tends to leave less soot behind. I've had limited luck with gasoline sprayed from a windex bottle, try a squirt for every ...
by Fnord
Thu Aug 20, 2015 11:40 am
Forum: Hybrid Cannons
Topic: Automatic Piston Hybrid Cannon Design
Replies: 27
Views: 5905

Re: Automatic Piston Hybrid Cannon Design

In all honesty, if this is your first hybrid or first large-scale build with a college machine shop at your disposal, just go for a standard 10-20x mapp/air gun with a piston valve. After that goal is achieved, the breech and fueling can be automated with a bit of pneumatic/EE work. 5-10 shots per m...
by Fnord
Thu Aug 20, 2015 10:34 am
Forum: Pneumatic Cannons
Topic: Valve help needed
Replies: 9
Views: 1290

Re: Valve help needed

In my 1.5" valve there's a small bleed hole in the diaphragm that lets air into the chamber. Maybe you have a bit of debris plugging it up?
You should take pictures of the internals if possible, just so we can rule out any defects.
by Fnord
Sat Aug 15, 2015 9:54 am
Forum: Hybrid Cannons
Topic: Automatic Piston Hybrid Cannon Design
Replies: 27
Views: 5905

Re: Automatic Piston Hybrid Cannon Design

Checking his numbers, I think he's short by an order of magnitude. (Although it is past four in the morning here, so maybe I'm the one that's wrong). Your numbers are closer than mine, since I didn't do any 'real math' to come up with them: 1.6 megajoules muzzle energy / gun efficiency (assumed an ...
by Fnord
Sun Aug 09, 2015 11:06 am
Forum: General How-To & Discussion
Topic: Question about darts
Replies: 3
Views: 974

Re: Question about darts

Paper cone skirts soaked in superglue are fairly durable, and if it gets shredded you can just add more layers until it holds together.
by Fnord
Sun Aug 09, 2015 10:46 am
Forum: Pneumatic Cannons
Topic: Need A Golf Ball Cannon Built For Me
Replies: 5
Views: 1411

Re: Need A Golf Ball Cannon Built For Me

I am looking for someone to build me a cannon that shoots golf balls from the tee box to the green 450 plus yards I am willing to pay someone to build me 2 Lmk if you can help me P̶o̶s̶t̶i̶n̶g̶ ̶a̶ ̶v̶a̶g̶u̶e̶ ̶r̶u̶n̶-̶o̶n̶ ̶s̶e̶n̶t̶e̶n̶c̶e̶ ̶w̶i̶t̶h̶ ̶t̶x̶t̶-̶t̶l̶k̶ ̶a̶c̶r̶o̶n̶y̶m̶s̶ ̶a̶n̶d̶ ̶n̶o̶...
by Fnord
Sat Aug 08, 2015 2:38 pm
Forum: Hybrid Cannons
Topic: Possible Breech Load Hybrid. Quick change burst discs?
Replies: 6
Views: 1993

Re: Possible Breech Load Hybrid. Quick change burst discs?

I think it is just a matter of selection the high quality piston that will work awesome. I know a lot of users there can recommend us the best quality piston. :) This is kind of off topic but I am wondering how this guy has flown under the radar for over two years now. He's either an uncanny valley...
by Fnord
Thu Aug 06, 2015 11:38 am
Forum: Hybrid Cannons
Topic: Automatic Piston Hybrid Cannon Design
Replies: 27
Views: 5905

Re: Automatic Piston Hybrid Cannon Design

Just checking in and came across this semi-old post. Bump. Ignoring material considerations and inevitable destruction of moving parts, I'm wondering where one would acquire the 5 megawatt DC power supply needed to run this gun at full power? And also how to deal with multiple megawatts of waste hea...
by Fnord
Wed Aug 05, 2015 8:00 pm
Forum: BB, Airsoft, and Pellet Guns
Topic: Blocked vortex internal pressures
Replies: 5
Views: 1259

Re: Blocked vortex internal pressures

Ragnarok wrote:
mark.f wrote:Look who decided to show up. :P
Benedict Cumberbatch?? Where?
No, it was just Hasselhoff again. Nothing to see here.