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Better Luck Next Year

Unreasonable Rocket has dropped out of next week's competition. Congratulations for all of the progress and accomplishment, regardless. And the lesson here is one that NASA seems to have forgotten--the three rules of rocket design: margin, margin, margin.


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Paul Breed wrote:

In the plans We had 35% hover duration time margin.
We has a 25% peak thrust Margin

We just never got the mixing to happen correctly. We were at about 60% of the theoretical ISP and we still had enough performance margin to do the task, but with that low of ISP we did not have the flow in the main injector orifices to get the chamber pressure up where it needed to be to lift off.

Even 70% of theoretical ISP and we would have been good enough. I needed to pay more attention to the weird pressure pulses and nonsensical
chamber pressure readings earlier on in the project.
I just assumed that while it was suboptimal I had enough margin.

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This page contains a single entry by Rand Simberg published on October 17, 2008 7:56 AM.

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