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HYBRID Rocketry HYBRID ROCKET REQUIREMENTS 85 % - 88 % solid ; 12% - 15 % binder Oxidizer/Fuel Requirements:
Oxidizer Possbilities:
Fuel Possibilities:
Binders:
Tentatively Out: Reccommended:
Have you guys and Gals seen the NERO Hybrid Rocket ? These photographs should be self explanitory, but if you have any questions, e-mail me (Webslave) or (These photos and information are excerpts from the NERO-Eindhoven Homepage - be sure to check them out!)
The E-36 is a rocket which is powered by the "L" class HY-4000 engine. This is a hybrid rocket motor with a total impulse of 3800 Ns (4000 Ns was intended). The engine is developed by NERO-Eindhoven, and the rocket is constructed around a commercialy available aluminum tubing, combined, they weigh about 14 kg (~31 lbs) at lift-off. The rocket is equiped with a dual stage parachute system. The drogue chute is released at apogee. At an altitude of approximately 500 meters, the main parachute is released. The rocket was originally designed to achieve an altitude of 3000 meters, which is about the maximum allowable launching altitude in The Netherlands. The E-36 rocket was succesfully launched September 20, 1996. HY-4000 Hybrid Rocket Motor The HY-4000 rocket motor was especially designed for the E-36 rocket. Trajectory calculations showed that a rocket motor with a total impulse of about 4000 Ns would be necessarry to launch the rocket to the planned 3 km. The HY-4000 uses Nitrous Oxide (N2O) as the oxidizer and hydroxyl terminated polybutadiene (HTPB) as the fuel. A launch acceleration of about 7-10 G's is desirable for a stable flight, so the engine has to deliver a thrust of 1100-1400 N at ignition. With a total impulse of 4000 Ns, this means a burning time of 3 seconds. As the regression rates of hybrid fuels are low, a multi ported grain with six ports was designed and built. Note Spheroid shape with concentric expansion, to allow for the low regression rate. Computer simulation of the regression of the multiported grain. The fuel grain is vacuum cast in a phenolic paper liner, shown in the above figure as the tube around the propellant. The liner is not completely filled during casting to create a post combustion chamber. The combustion temperatures of nitrous oxide based rocket propellants are high, so the stainless steel nozzle is fitted with a graphite insert. This insert has to be replaced after two or three tests. As the liquid nitrous oxide is injected during flight, the HY-4000 is tested in a vertical test bench. The small test bench used for the E-39 rocket was modified for this purpose. During the first static test the power of the engine was underestimated, and the blast deflector broke app. 0.5 seconds after ignition. These engineers/scientists are using rather novel technology -
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