<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by *something ridiculous:
I noticed from his member profile that pwell is a real-life Rocket Scientist !
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Woah! I wish!
I have been into rocketry for a fair while, but just decided to get serious about it about a year ago.
I'm into amateur rocketry, which is basically building rockets from the engine up from scratch. I've built a 40-cm long, 4-cm wide hybrid rocket engine using pretty easy to find materials. Its been tested twice. The second burn lasted 5 seconds with an estimated thrust of about 15 kg.
In a hybrid rocket either the fuel or oxidizer is a solid and the other is a liquid. Generally, there is a solid fuel grain and a liquid oxidizer. Hybrids are very safe to transport and store, since the fuel grain is innert. The oxidizer of choice by most amateurs is nitrous oxide (laughing gas or N2O). N2O is preferred because it is self pressurrised (about 750 psi at rom temp) and the oxygen is locked in until it reaches about 500 deg C. Fuel grains can be made from PVC, wood, rubber etc. I use PVC.
The N2O tank I use is custom designed and built; one piece of Al pipe is used for both the tank and combustion chamber. Filling is done remotely using an electronically operated solenoid valve.
I think solid fuel rockets are easier to start on, but I chose hybrids for safety. I dont want to be storing live rocket engines at my place since its only a one room apt. Hybrids are also refillable.
I expect the final rocket will fly to about 1500 m. Fun things you can do are putting a camera on the nose cone, rocket drag racing, rocket assisted take off, increaing rocket size...
That was a pretty basic overview. I do have specs and many pics, but specs can be boring.
There are actually many similarities between rocketry and flashlight building...
lathe work, anodizing, o-ring seals, making threads. Btw, the aluminium I use for rockets is 6061, which is supposed to tear open on exploion. If I used the same 2024 Al I use for flashlights it could shatter the same as a hand grenade- Not nice for the Sunday bystanders.
Well thats enough blabbering! Hope it was of some interest.