F-35B - Swivel Nozzle
5:21 PM on Dec 09, 2011
This post is one in a series on the development of the F-35. Click here for a Flash graphic with system cutaways. Click on Read More to read the entire post on that system and check out next week's special coverage of the program in the Dec 12 edition of AW&ST.
The problem with the three-bearing swivel module (3BSM) between the engine and nozzle proved to be producing it. To vector 18,000lb of engine thrust by up to 95° in pitch and ±10° in yaw, three titanium casings must rotate relative to each other via ring bearings - two of them at 45°.
Graphic: Rolls-RoyceThe complex-geometry casings - which must be perfect circles when cut at 45° - proved difficult to produce and had to be brought in-house by lift-system supplier Rolls-Royce, which says they are now being manufactured reliability and on schedule. The bearings are driven by fueldraulic actuators and ring gears.
Flight testing uncovered vibration of the large underfuselage doors that open to allow deployment of the swivel nozzle. A stiffer back-up structure for the doors has been designed to avoid any limitations on flying.
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