Lesson 25 - Launchers/Guns

What are the factors in the fire control problem?

1. Continuously measure present target position

2. Effects of relative motion

3. Effects of interior and exterior ballistics

What are examples of launchers?

• Person throwing grenade

• Rifle firing a bullet

• Missile launched from rail

• Torpedo launched from tube

How does a weapon launch?

• Gravity: released and falls from launcher

• Reaction: weapon provides own thrust to separate from launcher

• Impulse: weapon pushed away from launcher using ejector or gun type

Reaction launcher

• Thrust to separate weapon from launcher is created by the weapon itself

• Separated into: canister and rail launchers

What are reaction launchers separated into?

Canister and rail launchers

Rail launchers

Make use of rails, tubes, long ramps and tall vertical towers to constrain a weapon system while it begins flight providing considerable flight control (ex: sea sparrow)

Impulse launcher: ejector type

Compressed gas, mechanical force, or EM force used to push weapon away from launcher

Impulse launcher: gun-type

Use a propellant to generate high pressure at a controlled rate to push a projectile away from a launcher

Gun-type launchers projectile design

What determines pressure in an impulse gun-type launcher?

Propellant mass and burn rate

For a small barrel, do you want degressive or progressive burn?

Degressive (FAST) – high pressure early

For a long barrel, do you want degressive or progressive burn?

Progressive (SLOW) – high pressure later

What factors affect muzzle velocity?

Projectile weight, erosion, barrel length, temperature

Recoilless launchers

Propellant gases discharged rearward recoilless

Muzzle break

• Reduce the forces of recoil by attaching baffling to the muzzle

• Momentum of redirected gas offsets SOME of recoil momentum

What does barrel rifling cause?

Projectile to spin as it travels down barrel → aerodynamic stability