Problem with F4's BLC system was maintenance. Not needing the original
fence speed of 122 KIAS, USAF blanked off the engine bleed ****ts and
settled for 144 KIAS. With the F4's BLC system using 17th stage
compressor bleed air that air was running about 250 PSI and ca 750F at
full military power. A valve stuck open, even with the flaps up, that
hot air could leak from the ducting and could and did start fires,
usually resulting in the loss of the aircraft. Two of my friends did
have to eject from their F4 after the hot air damage resulted in loss
of hydraulic power to the flight controls. . No wonder civilian jet
trans****ts do not use bleed air for augmented lift.
Walt BJ
