Rob Coppinger, Flightglobal’s tech and space editor, is covering the AIAA Joint Propulsion Conference in Denver, and he reports:
Wing drop in high rate transonic turns is a problem because it results in a turn becoming a roll.
Because leading and trailing edge flaps may not be enough to counterthis phenomenon, the carrier variant F-35C will have a 4.5kg (10lb)spoiler added to the centre of its outboard wing for the test programme.
Lockheed currently believes the potential wing drop problem can be resolved with flight control software changes, but the spoiler will be added at least for the flight test phase.
Brig Gen David Heinz, F-35 program executive, told reporters on 3 June that the experience gained from the Boeing F/A-18E/F program had helped them resolve the wing drop issue for the F-35 in simulation. At the time, I interpreted Heinz’s statement as meaning such a wing fence or spoiler or would not be necessary, but that was an incorrect assumption on my part.
If you’re wondering how the spoiler will affect the F-35C’s radar cross section, Coppinger put that question to Lockheed executive JD McFarlan, who replied: “It has been designed to be LO [low observable, or stealth]-compliant”.