Quite so, Glueball, but I'd heard that the Trident had a specific 'air brake mode'. Using this, the main gear (not nose gear) was deployed and the gear doord closed afterwards (when the gear was deployed for landing, doors remained open). Thus the aeroplane could be dived a high airspeeds with loads of drag. The Trident's main gear had 4 wheels per side, 2 each side of the gear leg rather than the more conventional 4-wheel bogie, so was particularly draggy.
But - is it a myth or did the DH121 indeed have this facility??
SSD