Guys,
Just thought it might be helpful if I made a further post on this STOVL ski jump stuff.
LO is quite right in that the powered lift system on the F-35B can't vector all the thrust aft like the Harrier does. That's part of the trade off in getting your main propulsion engine located at the rear of the aircraft, where it really belongs for a fighter/strike type aircraft.
The lift fan can vector aft to around 50 degrees: on the X-35 there was a sort of 'pram hood' device that gave further aft vectoring - however, this was replaced in development by a much lighter 'vane box' device (UK designed) which still gave enough aft vector to meet the requirements. These were a set distance for a flat deck STO, and another shorter distance for a ski jump launch. The launch weight was driven by a defined operational scenario. J
The roll posts deliver around 2000 pounds thrust each in balanced operation, but they are turned off during the STO run and switched back on just before launch. This facility was suggested by a very talented RN FAA air engineer, and gratefully adopted during the weight saving programme. Another excellent Brit contribution.
The point overall is that the F-35B meets all its STO requirements, as well as its short landing targets. And it's a much heftier bird than the Harrier - over 55000 pounds off the ramp.
Happy to keep this sort of stuff coming as long as it helps. Do let.me know when I start boring people.
Best regards as ever to young and talented navy aircraft engineers
Engines
Last edited by Engines; 25th Apr 2014 at 17:19.
Reason: Clarification