The tanker had a 350/0.90m Vmo/Mmo and you could cruise ALL day long at those speeds but go beyond 0.90M and she went into a Mach tuck and you had to get the power to idle and the boards UP or she was off to the races. Not pretty.

The 727s we had could be flown in the A mode if your ZFW or max weight was below a number and if higher you had to fly in the B mode which was limited to about 350kts. In the A mode, however, you could run above 400kts indicated. (just came to me.. ZFW 136,000 or T/O above 176,000). The Tri-Motor was a great machine and flown by the numbers, it was a reliable airplane that would do just about anything you asked.