Since raising this question (ie what did David Campbell mean...) over a year ago (post #1) I can now tie up my loose ends. I have concluded his statements are most insightful. I hope I've interpreted them correctly.
It revolves around an afterburning turbojet reaching the flight speed at which the engine becomes a "drag item" (compressor still at 100% mechanical RPM but fuel flow now limited by "new-high" (J58 1300 F) comp delivery temperature and existing "redline" turbine entry temp (J58 2000 F). The afterburner is still getting 100% flow together with its temperature rise of about 1700 degF (P.Law's presentation Fig. 9).
So, ref D. Campbell "engine is inducing flow and heating it up with maximum afterburner".
He was not referring to the secondary flow as I originally thought but the main engine flow.
Engine is pumping (but not much else, in terms of thrust production that is, except the very necessary cooling flow for the afterburner, at 1050 F instead of at EGT 1450) at 100% speed, ie flow part of thrust. Afterburner is enabling airframe secondary nozzle to provide the velocity part.
ref D. Campbell "If the AB is reduced to minimum AB, the engine would actually be dragging on the engine mounts at high Mach numbers."
The engine is already a "drag item" at this speed because even with min AB the force on the mounts (ie complete engine incl AB) is still a drag.
Perhaps the engine "drag" is intimated by the engine pressure ratio being less than one? (see P.Law's Fig. 17 epr 0.9 at cruise). High Mach number still obtainable since thrust still from 100% flow and airframe secondary nozzle still has high pressure ratio.
ref D. Campbell "Further reduction of engine thrust below military power will result on no propulsive thrust on the aircraft".
The engine has been throttled back so reduced flow means high intake losses from off design, amongst many other things. No net thrust.
Comments welcome. Always trying to learn.
Last edited by peter kent; 22nd May 2014 at 21:42.
Reason: clarified meaning