Re: Vulcan Limit
Beags memory has slipped slightly, the Mk 21 delivered 70 mm pressure. We only switched to the low altitude Mk 17 after 1965-66 when our high level lkit was withdrawn.
The NBC Calc 3A had height range of 17200-60000 feet which limited our ability to conduct computed bomb runs below 18000 feet. About 1968 the Mk 1 Calc 3s were retrofitted to the Mk 2 Vulcan which gave us the same height range for ballistic computation at 7200-50000.
This meant we could now do 2G attacks (popup to 8000 feet). By this time we were doing laydown attacks and did not need to use the Calc 3 for ballistic calculation.
FJJP, I concur with your height, we got 555 over Glasgow at about 120k on an air test and gave up with a ROC of about 300-500.
I have just done some ODM work and was surprised to find the height over target would be only 530-540. Once the 21000 lb load had gone we could continue to cruise climb to 560.
Aerodynamic suck was not an issue in the mid 60s and was only 'invented' after the switch to the Mk 17 regulator and the suggestion that we limit our upper level to 450.
The Lightning, with the 21F regulator and the Taylor helmet could go to 660.
It wasn't the aerodynamic suck that worried me but the 45000 feet free fall if we had to bail out.