The scram cannon is a hypothetical kinetic energy

Kinetic energy

The kinetic energy of an object is the energy which it possesses due to its motion.It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes...

 weapon

Weapon

A weapon, arm, or armament is a tool or instrument used with the aim of causing damage or harm to living beings or artificial structures or systems...

 based on ram accelerator

Ram accelerator

A ram accelerator has the same function as a gun; i.e., it is a device for accelerating projectiles; however, it is entirely different in that jet-engine-like propulsion cycles utilizing ramjet and/or scramjet combustion processes are used to accelerate a projectile to extremely high speeds...

 technology. The scram cannon uses a projectile that uses supersonic combustion ramjet technology to increase the muzzle velocity to levels that are impossible with normal gunpowder

Gunpowder

Gunpowder, also known since in the late 19th century as black powder, was the first chemical explosive and the only one known until the mid 1800s. It is a mixture of sulfur, charcoal, and potassium nitrate - with the sulfur and charcoal acting as fuels, while the saltpeter works as an oxidizer...

 based guns; firearms are limited by the speed of sound

Speed of sound

The speed of sound is the distance travelled during a unit of time by a sound wave propagating through an elastic medium. In dry air at , the speed of sound is . This is , or about one kilometer in three seconds or approximately one mile in five seconds....

 in the propellant

Propellant

A propellant is a material that produces pressurized gas that:* can be directed through a nozzle, thereby producing thrust ;...

 gases, which limits the velocities to about Mach 5 (see internal ballistics

Internal ballistics

Internal ballistics, a subfield of ballistics, is the study of a projectile's behavior from the time its propellant's igniter is initiated until it exits the gun barrel...

).

Description

A scram cannon uses a sealed barrel filled with a fuel/oxidizer mixture that undergoes supersonic combustion as the projectile passes by. The energy liberated by this combustion acts to propel the projectile through reaction, like a jet or rocket engine, rather than by pressure as in a gun. This allows the scram cannon to launch sizeable projectiles at velocities previously only attainable with railgun

Railgun

A railgun is an entirely electrical gun that accelerates a conductive projectile along a pair of metal rails using the same principles as the homopolar motor. Railguns use two sliding or rolling contacts that permit a large electric current to pass through the projectile. This current interacts...

s, light gas gun

Light gas gun

The light-gas gun is an apparatus for physics experiments, a highly specialized gun designed to generate very high velocities. It is usually used to study high speed impact phenomena , such as the formation of impact craters by meteorites or the erosion of materials by micrometeoroids...

s and rocket

Rocket

A rocket is a missile, spacecraft, aircraft or other vehicle which obtains thrust from a rocket engine. In all rockets, the exhaust is formed entirely from propellants carried within the rocket before use. Rocket engines work by action and reaction...

s, but with significantly simpler techniques. Scram cannons often show up in science fiction

Science fiction

Science fiction is a genre of fiction dealing with imaginary but more or less plausible content such as future settings, futuristic science and technology, space travel, aliens, and paranormal abilities...

 and role-playing game

Role-playing game

A role-playing game is a game in which players assume the roles of characters in a fictional setting. Players take responsibility for acting out these roles within a narrative, either through literal acting, or through a process of structured decision-making or character development...

 discussion boards.

Development

The concept of a supersonic combustion ram cannon was patented in 1988, and versions were built as far back as 1994 to research scramjet

Scramjet

A scramjet is a variant of a ramjet airbreathing jet engine in which combustion takes place in supersonic airflow...

technology.