Questions in relation to the design of Rockets

trfinck

Hey everyone, I'm in the process of designing a rocket that could achieve high(er) altitudes. Of course, I want to make the rocket as small as possible, but maximize the height. I understand that the Mass fraction of the craft should be 0.91, where 91%~ is fuel/propellant, 6%~ is payload, and 3% is structural.

My basic question is, assuming my initial weight(total) was around 500kg, what would be the best propellant/fuel to get the most distance? (cutting out factors such as air resistance and so forth)

Thanks in advanced!

enigma

Your mass fraction should be as high as you can make it. It just works out that 9:1 fuel to everything else is a typical value. The final velocity (and as a result the high/distance it can travel) is entirely dependant on the specific impulse of the fuel and the mass fraction.

That said - you need to define a little bit more. Are you talking solid rocket, hybrid rocket, liquid rocket? Are you really building something, or is this a thought experiment? Does it need to be practical, or would killing a bunch of people in range of the exhaust plume be ok?