CONCORDE SST
Droop Nose

Concorde needs to be streamlined for supersonic flight, with a very long pointed nose to reduce drag and improved aerodynamic efficency. During take off and Landing Concorde flies with a very high angle of attack (high nose angle) this was required due to the way the Concorde delta wing produces lift at low speeds. At these low speeds with the high attack angles the streamlined nose would prevent the pilots seeing correctly during take-off and landing operations, so a unique solution had to be found.

The solution the engineers came up with was for Concorde to have a drooping nose that could be configured differently during the appropriate stages of flight. The aerodynamic loads and high temperatures at supersonic speeds also required a protective streamlined visor for the windscreens to be manufactures, this would also have to be re-positioned for take off and landing. The Visor is made out of special heat-resistant glass and is slightly tinted, and the outside panels are hinged for access.

 

The nose and visor mechanisim is hydraulically controlled from the aircraft's green hydraluic system, and its movement is initiated from a four position locking lever on the front panel of the cockpit, next to the first officer.

The 'traffic lights' give the nose's status during operation. along with an electro-magnetic "barber-pole" indicator.

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 hydraulicaly, with its downward movement occuring under gravity or aerodynamic forces

A 3rd manual, uplock release, system allows the nose and visor to freefall (to the 5 degree positon) should the yellow systems also fail

 

Droop nose modes and operation

Position 1

Nose and Visor fully retracted in up position
Used during Supersonic cruise and when parked

Position 2

Nose fully up, Visor retracted into droop nose
Used during short subsonic cruise (eg fly past) and windscreen cleaning

Position 3

Nose down at 5 degrees Visor retracted into droop nose
Used for take off and taxi

Position 4

Nose down at 12.5 degrees up, Visor retracted into droop nose
Used for landings and taxi, although raised quickly to position 3 to avert damage

 

Mechanisms

 

Droop Nose Jacks
(cylinders to the left)

Up Lock
(to the right)

The nose is situated to the front of the forward pressure bulkhead, but is hinged roughly under the pilots seats. The nose moves on carriages that run on either side of the pressure bulkhead.

The nose is actuated by a pair of tandem hydraulic jacks that work in parallel. both jacks have their upper cylinders attached to the forward pressure bulkhead and their lower cylinders to the nose structure. The two jacks provide alternate load bearing paths. A pair of up-locks engage in the up position to secure the nose to the bulkhead, allowing the hydraulic pressure to be removed from the jacks. When the nose is lowed hydraulic pressure keeps it in place and stops aerodynamic forces acting on it and moving it.

Visor "A" frame
(top)

Visor Uplocks
(centre under A frame)

)

The visor mechanism to contained within the droop nose. The visor is carried on two rails by carriages. It is raised and lowed by a hydraulic jack connected to the carriages by an A frame. The Visor, like the nose has an up-lock fitted, but his held in the down position by hydraulic pressure.