High Plains Rocketeer
- Jun 2, 2009
- Reaction score
- My Old Kentucky Home
Wouldn't operating at a higher chamber pressure, result in greater combustion efficiency? And hence,greater Isp? I think a 20% increase in BP Isp would warrant the use of CFRP casings like Aerotech uses for their Q-jets. Except dump that dang pressed clay nozzle and replace it with a screw-on nozzle.I just did. Propep says that Isp would increase...but not all that much. Theoretical Isp for BP at 250 psi is around 111 seconds. At 750 psi it's around 126 s. Assuming that the actual Isp at 250 psi is only around 80 seconds due to combustion inefficiencies, that suggests that actual Isp at 750 psi would be around 90 seconds.
I doubt that a 10-15% increase is worth the trouble of developing the technology, especially for a motor company.
As Ed Brown once told me, the Best BP in terms of Isp is BP that has high carbon charcoal, which depends on the wood used and how it's cooked.
Unfortunately cooking charcoal to achieve this is more an art,than a science.
By cooking I mean carbonization under heat and pressure.