Coffin corner - Concorde

[Bellerophon]

dynamite dean

At slow speed, Concorde’s delta wing didn’t stall in the conventional sense, the drag just kept increasing as you slowed up, until you reached a speed where, even with full power applied, you only just had enough thrust to fly level. This speed, called the Zero Rate of Climb speed, VZRC, could, broadly speaking, be regarded and treated in the same way as the stalling speed on a conventional aircraft, that is, best avoided.

In order to stay well clear of VZRC, operationally another speed was used on Concorde, called the LOwest authorised speed, VLO, which was the slowest speed the aircraft was permitted to fly at.

At high speed, things were more conventional, however, in any significant Mach overspeed, it was likely that the nose Temperature Maximum Operating limit, TMO, of +127°C would be exceeded before any untoward aerodynamic effects were experienced.

Now, to put some numbers to it, at her maximum authorised altitude of 60,000 ft, Concorde cruised at M2.00, around 430 kts IAS. The high speed limit, MMO, was M2.04, around 440 kts IAS, and the low speed limit, VLO, was 300 kts, around M1.41.

How the designers did it, I don’t know, but they came up with a superb aircraft which, even at maximum altitude, had an indicated speed range of 140 knots or 0.63 Mach.

Coffin corner? More like coffin plateau!


BOAC

At a rough extrapolation, VLO, as an IAS, would be equal to M2.00 around 73,000 ft.

Far too high for someone trained at Hamble not Cranditz.


Regards

Bellerophon