Step 1: Wall
it is possible to decrease the mass of the walls to increase the height it travels, but this also destabilizes the trajectory. this can be done by entering options>geometry and then moving the slider marked as density.
Step 2: Cap
that's right the rocket didn't have anything holding it together. nor did it have any thing to direct the fuel downwards.
so we need to make a cap. the same rules about density and size apply to this that do to the walls.
next the cap must match the with of the walls exactly, and be perfectly centered. (this is more important the higher you go.)
we need to attach this to the walls using the fixate tool.
Step 3: Fuel
1st is liquid pressure fuels.
2nt is solid object spring fuels.
3rd is solid object pressure fuels.
liquid rockets are arguably the easiest to fuel. all that is needed is to make several objects inside the rocket and liquefy them in options>geometry.
spring rockets work by attaching springs to the walls of the rocket and to the fuels objects. by decreasing the target length the object will be forced out faster.
the last is the one I shall demonstrate. solid object fuels provide some interesting options. first is shape. wile the majority are circular rectangular has its advantages to. with rectangular fuel it is possible to direct 100% of the pressure downwards because the overlapping objects try to separate as quickly as possible. IE the rectangles go towards the long side.
for this instuctable I'll be using circles or ball depending on you preference.
now the fueling process can be long or short depending on how you do it. the longest way is to make hundreds of shapes with one of the tools. I don't recommend this. not only do you get inconsistent thrust but it takes forever. next is to clone one object. this still takes a wile but is more reliable than drawing. next is copy paist. this is fairly quick and reliable. the last is to use a chain with low breaking strength. this last one I like the most. it is the fastest solid ball option and can be duplicated easily.
Step 4: Pressure Equilazation.
hit the key and watch it fly.