Gentlemen:
Check out the press release on the aerospike rocket flights on the NASA-Dryden web site at:
The aerospike is a centered Prandtl-Meyer all-external expansion design. It delivered 97% of ideal efficiency in ground test (exceeding historical Rocketdyne data), and theoretically would deliver the same high efficiency from sea level to vacuum flight conditions.
The rocket flights were to demonstrate operation of the aerospike in flight, and to measure installation effects compared to the uninstalled ground static firings. CFD was run not only for the aerospike hot gas flowfield, but for the combined rocket and aerospike plume flowfield.
This is the most highly instrumented high power/experimental rocket ever flown. In addition to highly accurate accelerometers and pitch, yaw, and roll rate sensors, the rocket used a conic nosecone with a built-in Flush Air Data System (FADS) (like a pitot tube), calibrated with CFD and cone pressure tables. This was the first inflight direct aerodynamic measurement of angle of attack on a model, high power, or experimental/amateur rocket.
An article for High Power Rocketry is in work, JANAAF and AIAA papers and tech articles in High Power Rocketry will follow.
Chuck Rogers Co-Principal Investigator
E-Mail: snipped-for-privacy@aol.com