PPRuNe Forums - View Single Post - F-35 Cancelled, then what ?
View Single Post
Old 24th Dec 2016, 19:40
  #10037 (permalink)  
SpazSinbad
 
Join Date: Jul 2008
Location: Australia OZ
Age: 75
Posts: 2,581
Likes: 0
Received 52 Likes on 45 Posts
For 'airsound' one or two of these snippets have been posted - probably - on this thread already, albeit some years ago now and they do not specifically address the bin lid question, they demonstrate testing and fixes for these doors plus the STOVL MODES, sadly not described here.
F-35 Begins Year With Test Objectives Unmet [STOVL IAS Change] 04 Jan 2011 Graham Warwick
http://www.aviationweek.com/aw/gener...p22-279507.xml

“...unreliable upper lift-fan door actuator redesigned, and no problems were experienced in the last quarter, he says. Vertical landings, halted since September after the discovery of wear on auxiliary inlet-door hinges, are set to resume this month. McFarlan says some hinge components have been redesigned & operation of the lift-fan door rescheduled to reduce airloads on the auxiliary doors during semi-jet-borne flight.

The lift-fan door was programmed to open to 65 deg. below 120 kt., and to 35 deg. above that airspeed. But with the large door fully open, loads on the auxiliary-inlet doors behind it are reduced, so the schedule has been changed to keep the lift-fan door open 65 deg. up to 165 kt. during a short takeoff, he says...."
F-35B - Doors (Pt. 2) Graham Warwick 09 Dec 2011
http://www.aviationweek.com/aw/blogs...entId=blogDest

“Dorsal auxiliary air-inlet doors, which open in STOVL mode to increase mass flow into the engine & generate an additional 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.”
F-35 Flight Testing At Pax [excerpt] Eric Hehs 15 Oct 2012
F-35 Lightning II Flight Testing At NAS Patuxent River | Code One Magazine

"...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,” Faidley said....

...The team is also flying the B‑model in conventional mode but configured with various STOVL doors open. “The flight conditions mimic failure modes,” Faidley explained. “For example, we intentionally open the upper lift fan door after the engine nozzle has converted from STOVL to conventional flight mode.”

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.”...”

Last edited by SpazSinbad; 25th Dec 2016 at 00:32.
SpazSinbad is offline