Heritage Concorde

Concorde’s airframe needs to be streamlined like a bullet to allow it to fly at supersonic speeds, to reduce drag and improved aerodynamic efficiency. This means that unlike other passenger jets, she needs a very long pointed nose which must also be a streamlined shape for supersonic flight.

Concorde  lands and takes-off with a very high angle of attack, this is due to the way that the delta wing produces lift at low speeds. At these high angles of attack, a fixed streamlined nose would completely obscure the runway, on landing the available view to the pilot would be only about 5 degrees.

The engineers came up with a solution to this problem; they designed a drooping nose, one that could be configured during the different stages of flight. The nose also incorporates a streamlined protective visor (Made of special heat-resistant, tinted glass) for the windscreens, required due to the high temperatures and aerodynamic loads of supersonic speeds

Both prototypes had a full metal visor with just two small glazed panels: from the pre-production 101, G-AXDN, onwards all Concordes were fitted with the fully glazed visor-altogether more attractive, both practically and aesthetically. Note the pictures at the bottom of this page, where you can see the prototype Concorde visor.

While it is normal practice to perform a take-off with the visor/nose at ‘down 5 degrees, the aircraft can, and has, made take-offs with them both ‘up’, quite satisfactorily. However, should one consider an approach and landing with nose/visor up, then firstly, 25ft of nose would give a distinctly poor view of the runway and secondly, the wheels wouldn’t come down! When the visor is raised up, an interlock isolates the ‘landing gear down’ circuits – a positive preclusion to inadvertent gear deployment at Mach 2: for the sake of a few feet of wire, probably worthwhile. The interlock always released, it never interfered with normal ‘gear down’ selection.

 The visor glass panels are laminations of two plies plus a thin non-stressed interlayer; gold film heating is applied to the inner surface of the outer panel. Total thickness is about 1.5 inch of heat-proof, very tough, impact-resistant glass.

 Although flight up to 325kts and Mach 0.8 authorised with the visor down, anything above 270kts is very noisy. During the flight test program of Concorde, 350 kts and Mach 0.8 had been achieved before the visor was raised for the very first time on flight number 11.

Initially 17.5 degrees was evaluated as the full down position. This was rejected as there was apparently a strong visual sensation of there being nothing ahead of one as the nose disappeared completely from view.

Both the nose and visor mechanism are hydraulically controlled from the aircraft’s number 3 green hydraulic system, and its movement is controlled from a four position locking lever in the cockpit, next to the first officer’s panel

A back up control is available on the centre pedestal that allows the nose and visor to be lowered using the yellow hydraulic systems if the green were to fail. The visor will be hydraulically retracted, but the nose will only be unlocked hydraulically, with its downward movement occurring under gravity or aerodynamic forces. In the event of a total hydraulic failure (If the yellow system was also to fail) or electrical failure, the nose uplocks could be released mechanically, allowing a nose free-fall to 5 deg. (the normal position for take-off, as opposed to the normal 12 deg, also as the nose lowered, the visor uplock would be automatically released to allow it to lower too. This was seen as acceptable for a landing).
The aircraft would never have been certified if such a system was not included.
Concorde’s droop nose and retracting visor were designed and manufactured under sub contract by Marshall Aerospace, at Cambridge Airport, UK, on behalf of the British Aircraft Corporation. http://www.marshallgroup.co.uk/index.html

 

1. Pitot Head  2. Radome

3. Weather radar scanner 4. Visor Hydraulic jack and retraction linkage

5. Secondary pivot head 6. Droop nose: Down position

7. Incidence probe 8. Visor rails

9. Drooping nose hydraulic jack 10. Retractable visor

11. Internal Windscreen panels  

 

 

 

 

 

 

 

 

Click here to read about Nose & Visor operations