WHY ARENT AEROSPIKE NOZZLES USED?
The following information comes from an article “Nozzle Design” by R. A. O’Leary and James E. Bech in the Spring 1992 (No. 8) issue of Rocketdyne’s *Threshold* magazine (call (818) 586-2380/2771 or write to Rockwell Aerospace/ Rocketdyne Division, 6633 Canoga Avenue, Mail Code AB57, Canoga Park, CA, USA, 91304-7922 to get a copy). At that same conference, I asked Max Hunter (“father” of the Delta rocket and a major player in the SSTO field) why it seemed that an aerospike was not baselined for the DC-X or the proposed DC-Y and DC-1. He replied that there was concern regarding the lack of *flight-test data* (he acknowledged that there was plenty of ground test data), in particular for the transonic regime. However, the Rocketdyne article states “. . . from Mach 1 to about Mach 3, *wind tunnel tests* (emphasis mine) indicate a drop in nozzle efficiency due to the slipstream turning into the nozzle region .. . . Nevertheless, the interval of time that is spent in this adverse flight regim
