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Then, assuming a circular bore, area takes the form A = πr2
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| Mathinline | body | \sqrt[3]\frac{40030 psi*0.0625 in}{720 lb*\pi} = r|
Another requirement of the piston is that it cannot break the shear pins prematurely due to an internal build-up of pressure caused by the altitude difference. Between 4,245 ft (the altitude of Truth or Consequences, NM) and 152,945 ft ASL (a simulated upper bound on performance as of January 4, 2018), the pressure difference is approximately (given by the 1976 Standard Atmospheric Calculator using no temperature offset) -86600 Pa. Thus, the following graph of maximum piston area based on the amount of shear pins used can be estimated:
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