Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 58 users online :: 3 registered, 0 hidden and 55 guests


Most users ever online was 218 on Wed Dec 07, 2016 6:58 pm

Registered users: Bing [Bot], Google [Bot], Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

High Pressure QEV Air Gun

Built a pneumatic cannon? Then post it here! This section is for completed, finished cannons that you have built. Please include pictures and information.
Sponsored 
  • Author
    Message

High Pressure QEV Air Gun

Unread postAuthor: MCRKilljoy » Sun Jan 01, 2017 12:43 am

I improved my air gun! I made the chamber twice as big, and used galvanized pipe instead of black iron. The ammo is AA batteries, metal bar sections, paper darts, mini marshmallows, steel balls, marbles, potatoes, or anything that fits in the barrel. At 120 PSI, I can get a muzzle energy of 100 joules with a steel bar. AA batteries get about 80 joules. I shot a computer case with an AA battery, and it punched through. The battery was heavily deformed. Steel bars don't deform, and they can go through 1" MDF. The launcher's tank is made of a 1" by 12" galvanized pipe nipple. The main valve is a 1/2" QEV rated to 150 PSI. The barrel is 1/2" copper or 1/2" SCH 80 PVC. The pilot valve is a 1/2" brass ball valve i had lying around, and the fill port is a 1/4' male air compressor quick disconnect plug. The back of the air tank acts as a stock. Since there is a 90 degree elbow for the QEV, I cut a strap out of a 2 by 4, and used a hose clamp to secure it. Image
  • 0

Last edited by MCRKilljoy on Sun Jan 01, 2017 9:46 pm, edited 3 times in total.
User avatar
MCRKilljoy
Private
Private
 
Posts: 12
Joined: Wed Dec 07, 2016 7:14 pm
Country: United States (us)
Reputation: 2

Re: High Pressure QEV Air Gun

Unread postAuthor: mrfoo » Sun Jan 01, 2017 3:16 am

foot/pounds are a measure of torque, not velocity. Are you sure you don't mean feet per second?

A quick calculation assuming around 20g for an AA battery gives around 3⅓ Joules.

Or maybe you meant foot pound *force*, which is a measure of energy and not velocity, in which case that's around 81 joules. Which is rather more respectable.
  • 0

User avatar
mrfoo
Corporal
Corporal
 
Posts: 64
Joined: Wed Apr 29, 2015 11:05 am
Country: Afghanistan (af)
Reputation: 5

Re: High Pressure QEV Air Gun

Unread postAuthor: MCRKilljoy » Sun Jan 01, 2017 12:59 pm

mrfoo wrote:foot/pounds are a measure of torque, not velocity. Are you sure you don't mean feet per second?

A quick calculation assuming around 20g for an AA battery gives around 3⅓ Joules.

Or maybe you meant foot pound *force*, which is a measure of energy and not velocity, in which case that's around 81 joules. Which is rather more respectable.

Thanks. I converted all the units to joules.
  • 0

User avatar
MCRKilljoy
Private
Private
 
Posts: 12
Joined: Wed Dec 07, 2016 7:14 pm
Country: United States (us)
Reputation: 2

Re: High Pressure QEV Air Gun

Unread postAuthor: Anatine Duo » Thu Feb 02, 2017 6:43 am

Quite appealing in its simplicity. The spacer between the reservoir and upper tube is a nice touch.

If you fire this from the shoulder does the pilot give you a blast of air?
  • 0

User avatar
Anatine Duo
Sergeant
Sergeant
 
Posts: 84
Joined: Sat Feb 01, 2014 11:16 am
Country: Canada (ca)
Reputation: 5

Re: High Pressure QEV Air Gun

Unread postAuthor: Ragnarok » Thu Feb 02, 2017 8:10 am

mrfoo wrote:foot/pounds are a measure of torque, not velocity.

Possibly slightly late and off-topic to answer this, but what the heck.

While this part is sort of correct, both torque and kinetic energy use units of foot-pound force, being a force multiplied by a distance. (So foot-pounds, not foot/pounds. They're multiplied, not divided).

That said, Imperial or the related US customary units (please don't call them "English units" - a lot of the US unit values are different from any that were ever used in England. Somehow they came up with an even more nonsensical system where fluid ounces lost any sensible relationship to ounces of weight) just are bonkers, with pounds being both weight and force.

In metric, torque and energy are still both units of Newton-metres, it's just that the derived unit of Joules is often used in the context of energy. (Of course, Newtons are also derived: kg m s^-2)

The relationship is that a torque of 1 Nm applied through an angle of one radian requires 1 Nm of work. As radians are dimensionless, being a ratio between an arc of circumference (a length) and the radius (another length), both torque and energy have the same units.
  • 0

Does that thing kinda look like a big cat to you?
User avatar
Ragnarok
Chief of Staff
Chief of Staff
 
Posts: 5366
Joined: Tue Dec 19, 2006 8:23 am
Location: The UK
Reputation: 10

Return to Pneumatic Cannon Database

Who is online

Registered users: Bing [Bot], Google [Bot], Yahoo [Bot]

Reputation System ©'