For 'Engines' some more F-35B 'Doors of Perception' trivia....
F-35B - Doors (Pt. 2) by Graham Warwick Dec/9/2011
Blogs
“Dorsal auxiliary air-inlet doors, which open in STOVL mode to increase mass flow into the engine & generate an add-itional 7,000lb of vertical thrust, were found to flutter in semi-jetborne flight, causing premature hinge wear. The initial fix was to modify operation of the large lift-fan door forward of the auxiliary inlet to stay fully open to higher airspeed on short take-offs to ‘shelter’ the clamshell doors. Instead of closing to the 35° mid position at 125kt the aft-hinged lift-fan door now stays fully open at 65° to 170kt on take-off, & begins to open to 65° at 160kt on approach to landing.”
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F-35 Flight Testing At Pax [excerpt] By Eric Hehs 15 October 2012
Code One Magazine: F-35 Flight Testing At Pax
"...The test team at Pax is also exploring the maximum speed end of the STOVL portion of the flight envelope, which is 250 knots. “The buffet and noise is significant when we have the upper lift fan door all the way open, which is an angle of sixty-five degrees, at that speed [250 knots],” Faidley said....
...Some of the flight test aircraft have special software that allows the pilot to override the standard control laws that actuate the various doors and nozzle angles. The flight control laws for the STOVL variant have six modes that are associated with specific actuations. Mode 1 defines conventional flight. Mode 4 defines STOVL. The other four modes define transitional states between the two primary modes.
“If a pilot loses a hydraulic system in Mode 2, we know that the doors associated with STOVL flight will be positioned a certain way,” Faidley explained. “We are seeing how well the airplane flies in those conditions.”...”