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RCS aerospike nozzles

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Charles_McG

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This is a good point and it might be why previous studies to investigate the axi-symmetric aerospike for commercial HPR were inconclusive. A way around this statistical variation would be to do a minimum number of trials, perhaps, 6 trials for example. At $36 a pop for the AT aerospike would be expensive, but it could be done.
You’d have to do some trials to see the actual variability before you can set the real number of tests. There’s a Power of the Test formula that relates the size difference you are trying to find - and what certainty, the standard deviation (perhaps standard error, I’ve forgotten) and the number of replicates.
 

aerostadt

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I can think of another benefit for aerospike nozzles. Perhaps, this is a stretch, because I don't know how badly the Aerotech aerospike gets beat up during a firing. In general in conventional convergent/divergent nozzles the highest erosion is at the throat. This means that the area ratio actually decreases during the burn and consequently the performance also decreases. However, for an aerospike nozzle it is not obvious that the performance decreases, because the area ratio no longer has any meaning, because the expansion is external. A larger throat may mean that a longer spike is needed and I don't know the role that the spike plays in this situation.
 

aerostadt

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I bought the Aerotech aerospike nozzle yesterday. It will be interesting to see what it looks like. I am looking forward to hearing the results of the Aerotech J1000ST motor.
 
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