Among the least known of all types of guns is the research cannon. Research cannon come in a variety of calibers, from about .177 (BB sized) to 3 inches. Research cannon are primarily used to conduct terminal ballistics experiments on material samples. Chiefly, these samples are armor and occasionally they are used for other purposes, such as to study the effects of debris impacts on spacecraft.
Research cannon larger than about 20mm normally use highly compressed air for the propellant. The reasons for air propulsion are economy, safety, cleanliness, predictability and turn-around time. Economy becomes a factor when you burn vast quantities of powder with each shot. Safety is a concern when handling large quantities of powder in an enclosed laboratory. Cleanliness is a factor the same as it is for any cannoneer, you swab between shots just like folks did 200 years ago.
Air is more predictable than any powder. As a result, air yields a shot-to-shot consistency that powder cannot match. Cleaning and reloading after each shot takes time. With a 3 inch cannon you can fire six times as fast as you can with powder. Note that sometimes a research cannon is called by two different numbers. For example a 20mm cannon may take a 19mm projectile when driving bands are used. Most of my experience with research cannon has been U.S. Army owned 20mm, powder fired. I had the option of converting to air, but at heart I'm a powder burner.
Research cannon can be highly versatile. With a 20mm gun you can load for muzzle velocities slower than 500 feet per second (fps) or faster than 4400 fps. This is because reseach cannon are normally smooth bores. It is desirable to fit the barrels within pipe sleeves equipped with adjustment bolts to remove barrel sag or bending. Research cannon are modular and can be reconfigured at will.
The projectile can be of any shape or length and uses driving bands or a sabot to fit the bore. Each projectile is custom machined for the experiment at hand. The projectile may be a model of a shell or a saboted rifle bullet.
The cannon is customarily fitted with a long, steel target chamber. The target (tested piece) is mounted inside of the target chamber. The reason for fitting a sealed target chamber is to allow the removal of air from both the cannon and target chamber. Removing the air lessens the chance that the projectile will yaw over the brief distance from muzzle to target. The target chamber also protects the researchers from debris hurled at high velocity by the impact. On occasions, sections of railroad cross-ties that I used to brace the targets were obliterated by the kinetic energy of the projectile. A few times only toothpick sized pieces remained.
Research cannon larger than about 20mm normally use highly compressed air for the propellant. The reasons for air propulsion are economy, safety, cleanliness, predictability and turn-around time. Economy becomes a factor when you burn vast quantities of powder with each shot. Safety is a concern when handling large quantities of powder in an enclosed laboratory. Cleanliness is a factor the same as it is for any cannoneer, you swab between shots just like folks did 200 years ago.
Air is more predictable than any powder. As a result, air yields a shot-to-shot consistency that powder cannot match. Cleaning and reloading after each shot takes time. With a 3 inch cannon you can fire six times as fast as you can with powder. Note that sometimes a research cannon is called by two different numbers. For example a 20mm cannon may take a 19mm projectile when driving bands are used. Most of my experience with research cannon has been U.S. Army owned 20mm, powder fired. I had the option of converting to air, but at heart I'm a powder burner.
Research cannon can be highly versatile. With a 20mm gun you can load for muzzle velocities slower than 500 feet per second (fps) or faster than 4400 fps. This is because reseach cannon are normally smooth bores. It is desirable to fit the barrels within pipe sleeves equipped with adjustment bolts to remove barrel sag or bending. Research cannon are modular and can be reconfigured at will.
The projectile can be of any shape or length and uses driving bands or a sabot to fit the bore. Each projectile is custom machined for the experiment at hand. The projectile may be a model of a shell or a saboted rifle bullet.
The cannon is customarily fitted with a long, steel target chamber. The target (tested piece) is mounted inside of the target chamber. The reason for fitting a sealed target chamber is to allow the removal of air from both the cannon and target chamber. Removing the air lessens the chance that the projectile will yaw over the brief distance from muzzle to target. The target chamber also protects the researchers from debris hurled at high velocity by the impact. On occasions, sections of railroad cross-ties that I used to brace the targets were obliterated by the kinetic energy of the projectile. A few times only toothpick sized pieces remained.
