Dixi188
I heard that the combined nozzle and reverser was a unique piece of aviation development.
The story I heard when I was an apprentice at Hurn was that, compared to the prototype multi finger nozzle and separate reverser, the production nozzle was:-
1. More efficient.
2. Lighter.
3. Simpler.
4. Cheaper to make and maintain.
Actually Rolls Royce always told me that the (new) Type 28 secondary nozzle was a bit of a dissapointment. Aerodynamically it was a far better interface with the wing from a drag point of view than the original design, but fell short of it's design promise in terms of performance. The design responsibility for the secondary nozzle system awarded to the French engine manufacturer SNECMA. They in turn farmed the whole manufacturing side off to STRESSKIN inc., a division of General Motors, and the air motor and electronic control unit were designed and built by Garret Airesearch in the US also.
The original secondary nozzle was 'freely floating, with no actuation; the thrust revereser itself was a pair of cascade doors, driven by an air motor. Tertary air doors opened at low speeds to admit ambient air into the nozzle anulus, instead of the eyelids of the later 'buckets'.
If you look at the diagram below you can see what a complicated animal the prototype powerplant was. The intake dump door (alternative name for spill door) was hinged both at the front AND the rear; either hinge mechanisms automatically releasing at specific Mach numbers. It was the mechanical nightmare that the diagram suggesrs.
Dude
