Search found 70 matches

by Kilash
Fri May 29, 2015 12:36 am
Forum: Ammo & Parts
Topic: 2.5" heavy round
Replies: 2
Views: 1099

Re: 2.5" heavy round

Looks like any standard aluminum beverage can to me? If you want to make it aerodynamically stable, you can just fill it with concrete or plaster halfway and leave some air space on the back end to make it front heavy, like a Brenneke or Foster slug. Fins I find that unless you make them dead straig...
by Kilash
Sun May 17, 2015 10:38 pm
Forum: Ammo & Parts
Topic: Burst pressure in a filament/wire wound cylinder
Replies: 8
Views: 1535

Re: Burst pressure in a filament/wire wound cylinder

Thinking you need the help of someone a good deal more educated on the subject than I. Suggest you contact D.Hall. As far as length wise stresses....going with .080" wall and 1" od...gives a bore of .84"...@ 4000psi, you're looking at a force of 2215 lbs. Won't take much of a tube to handle it in t...
by Kilash
Sun May 17, 2015 4:50 pm
Forum: Ammo & Parts
Topic: Burst pressure in a filament/wire wound cylinder
Replies: 8
Views: 1535

Re: Burst pressure in a filament/wire wound cylinder

Why? Lot's of work...what is it you're hoping to achieve that cannot be more readily achieved by conventional means? Damascus barrels fell out of favor for more reasons than labor intensive...simply not as strong as a steel tube. Simply to see if I can. I can easily order a piece of seamless 4130 t...
by Kilash
Sun May 17, 2015 12:42 pm
Forum: Ammo & Parts
Topic: Finding .177" pipe
Replies: 18
Views: 9674

Re: Finding .177" pipe

I use an oversized black iron pipe, namely just to contain any fragments or sharpnel if the barrel does indeed bursts, but it makes a cheap sleeve if you're worried about dropping and bending the barrel.

Vng, did you actually order this on Amazon??? How did that go?
by Kilash
Sun May 17, 2015 12:35 pm
Forum: Ammo & Parts
Topic: Burst pressure in a filament/wire wound cylinder
Replies: 8
Views: 1535

Re: Burst pressure in a filament/wire wound cylinder

An interesting problem :) ...not sure I can help but willing to have a go at it. With a diameter of .018", the area of each strand is .000254 in2. At 50 lbs breaking strength, the material tensile strength works out to 196,850psi. Curious as to how you derived a wall thickness of .080"? Planning to...
by Kilash
Sun May 17, 2015 12:39 am
Forum: Ammo & Parts
Topic: Burst pressure in a filament/wire wound cylinder
Replies: 8
Views: 1535

Burst pressure in a filament/wire wound cylinder

Attempting to determine an estimated burst pressure for a barrel that is made from an inner cylinder sleeve reinforced with thin fibre filament or wire winded and wrapped uniformly over the cylinder sleeve. This method of construction is used for composite oxygen/gas tanks and other high-pressure ve...
by Kilash
Sun May 17, 2015 12:00 am
Forum: Ammo & Parts
Topic: Finding .177" pipe
Replies: 18
Views: 9674

Re:

1/4" brakeline from the auto parts store of your choice. (NAPA) .177 pellets fit near perfectly, it'll handle several thousand psi, and the best for last.... ITS CHEAP. :D What I used for my .177 pistol, brake lines tubes make awesome cheap barrels, plus they come with brass fittings you can simply...
by Kilash
Sun Jan 12, 2014 2:06 am
Forum: Combustion Cannons
Topic: 1:1 C/B Ratio
Replies: 9
Views: 1684

Re: 1:1 C/B Ratio

jimmy101 wrote:I noticed that as well. Perhaps because of how the model treats the burst disk. The disk has to deform to fail and even though we've set the burst pressure to zero (i.e., no burst disk) the model still needs to deform it.
Ay, that makes sense. Thanks for weighing in :).
by Kilash
Sat Jan 11, 2014 12:36 am
Forum: Combustion Cannons
Topic: 1:1 C/B Ratio
Replies: 9
Views: 1684

Re: 1:1 C/B Ratio

Everything in the HGDT parameter set has to be set right. Here's an example for a 3" x 36" "monogun". The ammo mass and friction values are WAGs. On the right is a screenshot of HGDT, on the left is an Excel sheet where I collected data as I swung the chamber to barrel composition with a total leng...
by Kilash
Sun Jan 05, 2014 2:04 pm
Forum: Combustion Cannons
Topic: 1:1 C/B Ratio
Replies: 9
Views: 1684

Re: 1:1 C/B Ratio

Thanks for replying Jimmy. I actually did attempt to model the build with HGDT, but I keep getting mixed or irregular results with it, for example my pressures are very low unless I specify a burst disc pressure. Setting BD pressure to zero results in a peak pressure of only 5 to 7 psi, which can't ...
by Kilash
Sun Jan 05, 2014 12:36 pm
Forum: Combustion Cannons
Topic: 1:1 C/B Ratio
Replies: 9
Views: 1684

1:1 C/B Ratio

I have a build in mind that involves the barrel and chamber being of the same pipe. The "projectile" would be located halfway in the pipe, creating the separate barrel and chamber. 3 inch diameter, no above ambient mix, propane/butane fueled, no burst disc. What would my internal performance be like...
by Kilash
Fri May 31, 2013 11:16 am
Forum: Pneumatic Cannons
Topic: quick question; check valve as firing valve
Replies: 4
Views: 581

Yea i thought about that, so i was thinking maybe i have a screw bolt that i can adjust pressure on the seal disc. My working pressure is 70 psi.
by Kilash
Fri May 31, 2013 9:42 am
Forum: Pneumatic Cannons
Topic: quick question; check valve as firing valve
Replies: 4
Views: 581

quick question; check valve as firing valve

Hey guys, at lowes now and want to know your thoughts on modding a 2 inch pvc valve into a firing valve. Basically im gonna put the check valve in reverse, and put in a slide bolt to keep the check disc up against its seal to keep air in the chamber.
by Kilash
Wed May 29, 2013 12:01 pm
Forum: Pneumatic Cannons
Topic: permanent sabot/piston in barrel
Replies: 18
Views: 3787

What you suggest for a valve?
by Kilash
Tue May 28, 2013 11:54 pm
Forum: Pneumatic Cannons
Topic: permanent sabot/piston in barrel
Replies: 18
Views: 3787

Results are in, the sabot performed horribly. Firing out from a 3/4 barrel of the same length gave better muzzle velocity and energy for the same projectile. I thought it might had been the friction of the sabot, but i loosen its seal and its still performed worst. Could it be because I'm using a 3/...