Earlier quoted context omitted.
NASA CR-1998-207923 The Control System for the X-33 Linear Aerospike Engine by Jerry E. Jackson, Erich Espenchied, Jeffrey Klop "A secondary flow (turbine drive gases) is exhausthed throug the nozzle base and adds to the recirculating flow to increase the base pressure and the overall nozzle efficiency." http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/1998017... Had to curl it, since pdf.js always froze before l…
Thank you. However, turbine exhaust can't provide much thrust - both flow and speed aren't large. So the spike nozzle doesn't get much thrust from turbine gases - yet it can get it from chamber gases.
It's not very important, it's just names. This project is hardly the first one to not distinguish between spike nozzles and aerospikes.