Rocket Launcher

The Rocket Launcher (or RL, as it's known) is a weapon that has appeared in various incarnations in all of the Unreal games. Its behavior has remained fairly static: primary fire fires a single rocket, and secondary takes more time to load up before releasing multiple rockets. In all versions, the Rocket Launcher can "lock on" to targets if the crosshairs hover above a target for a brief amount of time. If the RL is locked on, rockets' paths will curve to try to intercept a moving target. However, this is relatively easily dodged and the target lock is easily broken if the crosshairs move away from the target before firing.

Unreal

See 8ball Launcher

Primary Fire

Fires a single rocket or multiple rockets if the fire button is held down.

Secondary Fire

Fires a single grenade or multiple grenades of the alt-fire button is held down.

Unreal: RTNP

Same as the Unreal Rocket Launcher, only this time around it's actually called a Rocket Launcher.

Unreal 2

A.K.A. Shark Behaves the same as the Unreal/Unreal:RTNP Rocket Launcher, with slightly different timing.

Unreal Championship

Unreal Championship 2

Primary Fire

Fires a single rocket.

Secondary Fire

Charges up to three rockets, each of which can split in two if activated in midair.

Unreal Tournament

Primary Fire

Fires up to 6 rockets at a time, released in a horizontal line formation or, by pressing alternate fire while loading, in a tight cluster.

Secondary Fire

Fires up to 6 grenades at a time. Grenades bounce from obstacles and explode after a certain amount of time or on contact with player.

Ammo

Upon pick up Rocket Launcher will contain 6 rockets, maximum ammo capacity being 48. Default ammo pack has 12 rockets in it.

Damage

Direct hit by rocket or grenade delivers 112 damage to a target.

Unreal Tournament 2003 and UT2004

Primary Fire

Fires a single rocket.

Secondary Fire

Fires three rockets in a horizontal line, and, by pressing primary fire while loading, can shoot up to three rockets in a tight spiral.

Unreal Tournament 3

The UT3 Rocket Launcher is reportedly about the same as that of UT2004, possibly without the capability to shoot only two rockets in a spiral.

Tactical Use

The Rocket Launcher's rockets fly straight, do a lot of damage in a direct hit, and have a fair-sized splash damage radius. (Because of the splash damage, Rocket Launchers are less than ideal for close-range fighting and are notorious for causing suicides in this situation.) In UT2003 and UT2004, Rocket Launchers, when they are picked up, have 12 rockets, and they can hold a maximum of 30. Rocket Launcher Ammo Packs hold 9 rockets each. It takes a bit under 1 second to load a rocket.

Rocket Launchers, since they are the most powerful standard weapon except a sniper, they have a reasonably fast reload rate, and have a large splash damage radius (hence the RL is called a "spammy" weapon) is a favorite of new players. Because it's much more rarely used by advanced players, the Rocket Launcher is often found opposite the Flak Cannon in Capture the Flag, Double Domination, and Bombing Run maps, and in either wide-open or very tight places in Deathmatch or Domination. The theory behind the latter locations is that a weapon is most balanced if it is placed in a location where it is least useful; since the RL is usually considered a mid-range weapon, these locations make sense.

(The following ideas (but not the text) are mostly copied from UnrealWiki)

Use in Onslaught (UT2004 only)

• Rockets have a lot of momentum, so they will temporarily stop or slow down Scorpions and usually change their direction slightly, disorienting the driver. Three rockets kills a scorpion.
• Since Rocket Launchers are the second-most-powerful weapon against vehicles (factoring in their rate of fire) they are the most useful weapon to combat Goliath tanks and other large, slow vehicles (not including the Hellbender unless it's coming straight at you) after AVRiLs. However, Mantas and Raptors are usually too agile to be hit by rockets.
• Because rockets fly very straight and cannot be shot down, they are ideal for shooting Power Nodes from a distance. A useful tactic if you're bad at aiming is to line up using the Lightning Gun or Sniper Rifle and then switch to the RL without moving.

Use in Deathmatch and other Gametypes

• Loading up on rockets before bursting in to an area where you know there are enemy players allows you to unleash a powerful attack on multiple enemies before they know what's going on.
• Players in the damage radius of a Rocket are lifted off the floor, preventing them from jumping or dodging. Good players can predict the landing spot and send another rocket there to greet the enemy. This ability can also be used to boost players themselves, although the Impact Hammer (in UT) and Shield Gun (in UT2003/4) usually take this role.
• Hitting the ground near a player's feet is easier than hitting a player because, well, it's a larger target and it's not moving. Often the splash damage is plenty to hurt the enemy. Jumping in the air gives an easier angle from which to aim at a player's feet.