'John Farley', 'Engines' and other worthies have mentioned this aspect of how the F-35B will VL on two columns of air (I recall the Farley InfraRed photo - those relevant posts are excellent IMHO) but I do not recall this snippet being on the forum.
The Ultimate Fighter? Air & Space magazine, February 2012 By Richard Whittle
The Ultimate Fighter? | Military Aviation | Air & Space Magazine
"...Now the F-35B can hover or land on two columns of air, one hot, one cold (by thermodynamic standards), and each moving fast enough to provide about 18,000 pounds of lift. Two far smaller streams of exhaust funnel down ducts to a small nozzle under each wing called a roll post, providing roughly 2,000 more pounds of lift apiece plus side-to-side balance and control. Unlike the Harrier, whose pilot has to manipulate the aircraft’s stick, throttle, and controls to swivel the nozzles by hand, the F-35B has flight control computers to do all the work of balancing the airplane atop its thrust.
Part of the lift fan’s genius is that it allowed designers to put the F-35’s engine at its rear, the best placement in a non-STOVL aircraft as well, says Paul Park, who left Lockheed last year after three decades but previously led the team of engineers who determined the outer shape, internal arrangement, and other major aspects of the F-35. Having two equally powerful columns of vertical thrust is yet another big advantage in a STOVL plane, Park adds, for in designing such an aircraft, “the number-one challenge is not just the lift, it’s getting the vertical lift balanced around the weight.” That’s why the Harrier’s engine is in the center of the fuselage, he says.
The cool air coming from the F-35B’s lift fan also “shields people around the airplane from the hot exhaust in the back,” Park says, and helps prevent the engine from ingesting its hot exhaust, which could cause it to stall...."