Rainboe,
My sincere apologies if you thought that I was taking a swipe at your post, I honestly thought that you'd made a genuine typo, particularly when the B747 Mcrit is awfully close to M0.83. Be assured that your excellent and well thought out posts are on my 'must read' list.
I too, have 'taken the pledge' to avoid fully developed stall tests forever, I survived the last hundred or so, and that was a hundred or so too many.
tornadoflyer,
Mach crit appears to be of little operational value compared to MMO
That's got to be the understatement of 2005! Sure, Mmo is an extremely relevant speed, but rarely used operationally. On a Day to Day basis, Mcrit is of extreme relevance in the determination of Climb, Cruise, and Descent Mach number. The high speed drag polar comes into play only after Mcrit is passed, whereupon total drag is then the sum of the Low speed and the High speed drag polars. Best Climb (Angle, Rate or Econ), Best Cruise (Max Range, Long Range or Econ), and Optimum descent (Max Range, Long Range or Econ)
ALL depend upon the relationship between the Mach Number chosen / computed and Mcrit. For an 'older technology' (but beautiful) wing like the B747, Long Range Cruise Speed will usually be in the vicinity of .02 to .04 above Mcrit.
Regards,
Old Smokey