The vortex ring gun is an experimental non-lethal weapon in which a blank cartridge

Blank (cartridge)

A blank is a type of cartridge for a firearm that contains gunpowder but no bullet or shot. When fired, the blank makes a flash and an explosive sound . Blanks are often used for simulation , training, and for signaling...

 is fired into a gun barrel that has a diverging nozzle

Nozzle

A nozzle is a device designed to control the direction or characteristics of a fluid flow as it exits an enclosed chamber or pipe via an orifice....

 screwed onto the muzzle

Muzzle (firearm)

The muzzle of a firearm is the end of the barrel from which the projectile will exit.Precise machining of the muzzle is crucial to accuracy, because it is the last point of contact between the barrel and the projectile...

. In the nozzle, the short pulse of high pressure gas briefly accelerates to a supersonic exit velocity, whereupon a portion of the exhaust transforms from axial flow into a subsonic, high spin vortex ring

Vortex ring

A vortex ring, also called a toroidal vortex, is a region of rotating fluid moving through the same or different fluid where the flow pattern takes on a toroidal shape. The movement of the fluid is about the poloidal or circular axis of the doughnut, in a twisting vortex motion...

 (Figure 1) with the potential energy to fly hundreds of feet. Click here for an introductory video to the gun operation and click here to listen to a chest high vortex ring approaching a target.

Operation

The nozzle is designed to both contain the short pulse of accelerating gas until the maximum pressure is lowered to atmospheric and to straighten the exhaust into an axial flow. The objective (Figure 2) is to form the vortex ring with the highest possible velocity and spin by colliding a short pulse of a supersonic jet stream against the relatively stagnant air behind the spherically expanding Blast Shock. Without the nozzle (Figure 3), the high pressure jet stream is reduced to atmospheric by standing shock waves at the muzzle, and the resulting vortex ring is not only formed by a lower velocity jet stream but also degraded by turbulence.

Partners

A study commissioned by the United States Marine Corps Joint Non-Lethal Weapons Directorate tasked the United States Army Research Laboratory to determine whether optimized vortex rings could be used for non-lethal crowd control. Overall management authority was assigned to the United States Army Materiel Command

United States Army Materiel Command

The U.S. Army Materiel Command is the primary provider of materiel to the United States Army.The Command's mission includes the research & development of weapons systems as well as maintenance and parts distribution....

, Alexandria VA with support by ARDEC Picatinney, NJ. Contributors to the study included individuals from Sara Corporation, Sonic Development Laboratory, EWS Limited, Berkeley Research Associates, Johns Hopkins University

Johns Hopkins University

The Johns Hopkins University, commonly referred to as Johns Hopkins, JHU, or simply Hopkins, is a private research university based in Baltimore, Maryland, United States...

, Pennsylvania State University

Pennsylvania State University

The Pennsylvania State University, commonly referred to as Penn State or PSU, is a public research university with campuses and facilities throughout the state of Pennsylvania, United States. Founded in 1855, the university has a threefold mission of teaching, research, and public service...

, Adaptive Research Incorporated, and the United States Army Aberdeen Proving Grounds.

Hardware

The end product was a kit that quickly converts an existing lethal weapon in inventory to a non-lethal vortex ring generator capable of human knock-down, marking with a dye, applying a malodorous chemical, or applying an incapacitating chemical. The kit, consisting of a nozzle with chemical reservoirs and belts of blank 40mm cartridges modified to detonate at pressures up to 100,000 psi (690 KN/sqN), was designed for the Navy MK19-3

Mk 19 grenade launcher

The Mk 19 Grenade Launcher is a 40 mm belt-fed automatic grenade launcher or grenade machine gun that entered U.S. military service during the Cold War, first seeing action during the Vietnam War and remaining in service today.-Overview:...

 40mm grenade machine gun because firing at 4-10 shots per second resonates with many body parts and causes a stronger impact effect.

Field Tests

Single shot field tests performed without optimized nozzles led to the conclusion vortex rings were unsuitable for non-lethal crowd control partly because knock down did not appear to be feasible at the desired range of 100ft (30M), and partly because of the excessive spillage onto bystanders under the flight path if used to transport chemicals or dyes. Some military field commanders may also be reluctant to convert a MK19-3 weapon to a non-lethal mode in hostile situations.

Technology Status

The foremost reliability issue with the 1998 Army initiative to launch high kinetic energy vortex rings using high explosives as propellant was turbulence caused by propellant burning outside the barrel. Launchers by commercial enterprises overcome the problem using less energetic gas propellants. The nozzle design for the Hail cannon

Hail cannon

A hail cannon is a shock wave generator claimed to disrupt the formation of hailstones in the atmosphere.These devices frequently engender conflict between farmers and neighbors when used, because they are repeatedly fired every 1 to 10 seconds over the period when a storm is approaching and until...

reliably fires vortex rings at one third the speed of sound or better. Knockdown of distant individuals seems unlikely even for launches at theoretical maximum speed of sound. The most likely military application may be the transport of chemicals if the higher spin reduces in-flight leakage.

External Links

• http://handle.dtic.mil/100.2/ADA351056 Overview of the vortex ring gun program
• http://www.youtube.com/watch?v=NbAQcxmXeIk Sound track of a vortex ring approaching a target
• http://www.youtube.com/watch?v=7wGUYHcXnlc Video of prototype vortex ring gun field tests
• http://handle.dtic.mil/100.2/ADA417311 Live rifle fire and computer modeling of the muzzle blast vortex ring
• http://handle.dtic.mil/100.2/ADA372518 Engineering design of the prototype vortex ring gun
• http://www.kselected.com/wp-content/uploads/2009/07/frey-rasmussen-mechanical-man-6-08.pdf Resonance of human body parts
• http://www.youtube.com/watch?v=GteGbZeKsOI&feature=related Video of a very high speed Hail Gun vortex ring
• http://www.youtube.com/watch?NR=1&v=QrgTtZXuj4w "Video of large structure knock down tests"