Alternate P1127 / Kestrel / Harrier layout

[PMN1]

Could the P1127 and therefore the Kestrel and Harrier have had the layout of the P.1216 design including the removable boom weapons modules and if so, how would that have affected its performance and later STOVL development?

 

[Mike Pryce]

The P.1216 needed carbon fibre to make it work - the torsion loads from the outboard tailplanes on the booms and inner wing were the main reason.

The Hawker P.1132 was looked at in the late 1950s, including a 'conventional' (i.e. Sea Vixen-like) twin boom layout with a tailplane between them.

However, it was only through experience of using the Harrier that the issues of the single rear fuselage became apparent.


Glad the book is of interest!

 

[PMN1]

The P.1216 needed carbon fibre to make it work - the torsion loads from the outboard tailplanes on the booms and inner wing were the main reason.

The Hawker P.1132 was looked at in the late 1950s, including a 'conventional' (i.e. Sea Vixen-like) twin boom layout with a tailplane between them.

However, it was only through experience of using the Harrier that the issues of the single rear fuselage became apparent.


Glad the book is of interest!

What did the look at the Sea Vixen like layout conclude?

 

[red admiral]

What did the look at the Sea Vixen like layout conclude?

It's quite difficult to have a swepth tailplane in that situation so I suspect the main issue would be having a lower Mcrit for the tailplane than the wing with consequent control issues. However, given Sea Vixen could go supersonic in a dive and Venom wasn't too bad, I would think M0.85/0.90 might be achieveable, at which point you've got massive drag increase from the large engine intake anyway.

I doubt that CFP was essential to making the inidvidual tailplanes of the P.1216 work, alu would simply add structural mass and reduce fuel and payload. Ok for a modern ~25,000lbf Pegasus, but not the 13,000lbf of the Kestrel/Harrier I era.

 

[Mike Pryce]

Although P.1132 was drawn before the P.1127 flew, a Sea Vixen tail would have major problems in transition as the induced downwash from the vectored nozzle jets would affect it, limiting control authority. Transition is the really hard part of V/STOL.


On the P.1216 the tailplanes were outboard largely to avoid the effects of the jet downwash. CFC was necessary to make the boom/tail layout work as the tailplanes and fins caused asymmetric twisting on the booms and inner wings, which aeroelastic tailoring from CFC could counter at an acceptable weight.