stupid semantics argument was raging
Clive, for my part I felt unless
Lyman could accept that all those associated with the program, including Bob Abernathy, called it a partial ramjet, we would be unable to move forward. How is one able to discuss something if you refuse to acknowledge its existence? Lyman was quite adamant that there is no such thing as a turbo ramjet or partial ramjet.
and your restraint, in limiting your post to single color, and consistent font
Just trying to get your attention
Lyman
The Flight Manual information,I believe, shows just a 2 position Bleed, closed or open. Thus when open it was a fixed orifice and as such controls to pretty much a fixed percentage irregardless of the actual mass flows.
You are correct that the bleed is an either open/closed system. It operates as a function of engine speed (rotor RPM) and CIT (Compressor Inlet Temperature), which has a maximum allowable limit of 427°C. As to a fixed percentage, I’m not so sure. Some detail.
The engine rotor RPM schedule (see attached graph) shows a continual decrease in RPM, starting at a CIT of about 110°C.
At high Mach number and constant inlet conditions, engine speed is essentially constant for all throttle positions down to and including IDLE.
At a fixed throttle position, engine speed will vary when CIT (Mach) changes.
The position of the nozzle is controlled by engine rotor RPM. Throttle movement in the afterburner range will also change nozzle position. At high altitude and maximum afterburner the nozzle will be 80-100% open normally.
As speed (Mach) increases the engine is provided less and less of the overall thrust. It seems intuitive to me that as the inlet, combined with the afterburner, is producing a continually increasing percentage of the thrust, then more and more bleed air, as a percentage, must be being bled off the 4th stage. Hope I make sense.
MAXIMUM ALTITUDE CRUISE PROFILE
The maximum altitude cruise profile is 1,000 feet below the maximum afterburner ceiling. Continuous use of maximum afterburner should not be required.
Effect of Mach Decrease
The Mach must not decrease appreciably below the desired cruise Mach. A small decrease in Mach at constant altitude will cause the aircraft to intercept the maximum afterburner ceiling for that speed and become thrust limited. A descent of several thousand feet may he required to re-establish the desired Mach.
Turn Restrictions
NOTE
Turns must be anticipated when flying near maximum altitudes. A descent of approximately 2,000 feet should he completed prior to turn entry.
Use of the maximum altitude cruise and maximum afterburning ceiling profiles is restricted to non turnlng flight. If 35° bank turns are attempted at these altitude schedules, the angle of attack will exceed 8 . Inlet angle of attack biasing will cause compressor inlet pressure to decrease as much as 2 to 3 psi.
Due allowances must be made for the expected altitude loss if maximum power will not be sufficient to maintain level flight.
Effects of Changing Air Temperature
Because of the high true airspeed at cruise, ambient air temperature may change abruptly as different air masses are encountered. Initially, if a constant altitude is maintained, flight into a warmer air mass will cause a decrease in Mach and KEAS, and the true airspeed (TAS) and compressor inlet temperature (CIT] will remain constant. A higher TAS and CIT will result as the desired Mach is reestablished. The opposite would occur as a result of flying into a colder air mass. New cruise altitudes or speeds may be required to compensate for effects of variations in ambient air temperature.
Effect Of Mach Number
For any given gross weight and ambient temperature, the altitudes for maximum range and maximum altitude cruise profiles increase with Mach. This increase is aprox 1,000 feet per .05 Mach. A related characteristic is that if Mach increases slightly above that desired and the throttles are not retarded, excess thrust increases. It is easy to exceed target Mach inadvertently. (peter, this I think is the kernel to your reducing fuel flow question.)
Mach, KEAS, Altitude Relationship
The selection of values for any two of the Mach, KEAS, or altitude variables automatically defines the value of the third, regardless of ambient temperature. For instance, if cruise is scheduled for Mach 3.0 and the desired initial cruise altitude is 72,000 feet, the KEAS must be 396 knots.