We’ve being trying to find old data on the 50 lbf engines we used back in the 1990’s for early peroxide monopropellant testing. I used to have detailed specs, but those docs (and a great many others) were lost in the fire of 2006. The plan had been to run a controlled batch of tests to optimize the performance (i.e. varying catalyst type and pack depth to find the best thrust) and then use 5 engines on the POGO (Proof Of Guidance Operations) vehicle. This was a small testbed for verifying guidance and control of a hovering rocket, similar (but a LOT smaller) to the DC-X. While a Mark 0 vehicle was put together, we never did get a proper vehicle flying, and the effort was superseded by the NASA Lunar Lander Challenge – which was won by Masten Space Systems, a spinoff of E.R.P.S.

Co-founder Kevin Bollinger sketched this out back in Jan 2000 and Dan found a copy and scanned it for us.

Blackhawk 50lb HTP engine

Drawing for POGO Engine