Ok, keep in mind that this is my first instructable, so sorry if it's a bit short on information. Anyways, my rocket shoots 30ft straight up. It is fun to launch, and my brothers like to try and catch it on it's way down.

Supplies

K'nex

Rods

gray/orange-31
red/green-65
yellow/dark gray-52
blue-95
white/light gray-56
green/black-69

Connectors

light gray/purple 1slot-23
gray 2slot-0
orange 2slot-51
red 3slot-15
green 4slot-20
yellow/light gray/black 5slot-56
white 8slot-14
gray/purple 4slot 3d-60
blue 5slot 3d-14

Other

black Y socket-8
orange y clip-17
light blue spacer-105
light gray spacer-65
blue clip-9
tan clip-1
size 32 rubber band-12

Step 1: Frame

Build this.

Step 2: Rocket

Build this.

Step 3: Trigger

The part on the end of the red rod is the grip, so if you want to modify it, feel free.

Step 4: Loading and Firing

So if you want to launch your rocket, just follow these steps. If you want to use my pics as a guide, you can.

Push the rubber bands down to about half way through the barrel and hook on a white rod.
Pull the rubber bands down the rest of the way down and hook on green connecters.
Slide the rocket down the barrel.
Insert the trigger into the hole, and make sure that it also went through back of the rocket.
Place the rubber bands behind the white rods on the back of the rocket.
Pull the the trigger.
(optional) Run away and hope it doesn't land on your head.