Main Article: Concjumping
Concussion jumps are the #1 way to cover large distances across the battlefield.
The basic premise is easy: drop a concussion grenade on the ground and then jump over it when it explodes. The resulting explosion propels you high into the sky. As with anything, practice is needed to get the timing and such down. Your direction of travel is based on the direction you are located relative to the grenade. Jumping directly over the grenade will send you up, jumping to one side will fling you horizontally. The concussion blast will also push you further the further away you are from the grenade itself, so for very long jumps you'll need to be right on the outskirts of the blast.
As an alternative, you don't actually have to drop the concussion grenade in order to do a concussion jump. Just let the timer run its course and jump when it detonates. The timing of this is more difficult than a regular "dropped" jump, but it is more powerful and flexible. You will be boosted in the current direction that you are travelling, so you will need to time your jump in order to be sent in the direction you want. Holding the concussion grenade and not jumping will still result in a small concussion jump forward, however the difference can be significant if you time a jump correctly.
Includes: Soldier RPG, Pyro IC
To rocket jump, run, look straight down, then fire and jump at the same time. That's all there is to it. It takes some time to learn the timing between the jump and firing the RPG, but with a little practice, anyone can do it.
Some variations on this jump:
The Pyro's IC is less powerful than the Soldier's RPG but can be used in combination with the napalm grenade to get a very big boost. Additionally the Pyro can 'glide' through the air by firing his flamethrower downwards to give a little vertical push upwards.
The flamethrower is a very useful tool to the Pyro who likes to fly through the sky. It has a jet pack-like effect that pushes you up a bit if you point it down and fire it while jumping. The height gain is not huge, but it can be used in conjunction with the incendiary cannon and grenades. By pointing down and firing while jumping horizontally, you can cover more distance. You can also use it to cushion falls to a certain extent.
Some things to note about this jump:
Explosive grenade jumps
Includes: Normal grenades, MIRV grenades, EMP grenades
Any explosion is going to assert a force on nearby objects. You can use this to your advantage by blowing yourself across the battlefield. Of course, you will lose a lot of health doing this, so you had better hope there is a health pack on the other side.
Basic dropped jump
This is pretty similar to the concussion grenade jump, only less powerful and it will hurt you. This time however you will need to be closer to the grenade to travel further, as the explosive force reduces over distance.
Once again this is very similar to the hand held concussion jump, only more tricky and painful.
Note that the explosive power of the Engineer's EMP grenade is relative to the amount of ammo in the nearby vicinity (including ammo that you are carrying). To get enough distance you will need to restock with lots of ammo in order to give yourself a good explosive boost.
Similar to dropped grenade jumping, only this time you can control when the explosion occurs. This makes it easier to time the jumps.