View Single Post
Old 19th Aug 2010, 13:37
  #28 (permalink)  
ChristiaanJ
 
Join Date: Jan 2005
Location: France
Posts: 2,319
Biggles78,
To complement M2dude's notes re nose and visor:

There were basically four 'positions':
Nose and visor up (supersonic),
Nose up, visor down only (subsonic climd and descent),
Nose down 5, visor down (take-off and initial climb),
Nose down 12.5, visor down (approach and landing).

Normally nose and visor are raised and lowered by the green hydraulic system (as is done until today on F-BTSD at Le Bourget).

In 'standby' mode, the visor was lowered by the yellow hydraulic system.
Then the nose uplocks were released by the yellow system, and the nose would free-fall to the 5 position.
Another switch allowed to hydraulically release the 5 downlocks, and the nose would free-fall again, now to the 12.5 psition.
In this 'standby' mode, the nose and visor could not be raised again.

In the best "belt, braces AND a piece of string" tradition of Concorde, if both the 'normal' and 'standby' system failed, there was a big handle on the F/O side of the central pedestal.
This released the nose uplocks manually, the nose would start to free-fall, automatically unlocking the visor, and both would then free-fall down: the nose only to the 5 position.

To complete the story... there is a 5th position: nose 17.5 down!
This was the 'nose fully down' position as designed originally and installed on 001 and 002.
It met with sharp criticism from the test pilots, because of the lack of a forward visual reference with the nose fully down. "It's like looking over the edge of a cliff", was the unanimous comment of the pilots.
So a couple of mechanical stops were added that limited the 'nose down' angle to 12.5.
But the basic design of the nose was not changed otherwise, so even on the production aircraft the nose could be lowered to 17.5, but only in the hangar, by removing the mechanical stops. It may have been done a few times, for better access to the visor and nose mechanism.

Minor anecdote... the nose and visor were up during supersonic flight, of course, but also when the aircraft were on the ground and parked outside, simply to keep the rain and dirt out.
But... the prototypes had a metal visor, with two tiny windows, and it was inconveniently dark on the ground in the cockpit with the visor up . So on the ground we always kept the visor down, unless the aircraft was parked outside for any length of time.
ChristiaanJ is offline