Boeing is examining modifying the wing on the F/A-18E/F Super Hornet in an attempt to solve a wing-drop problem, having exhausted options to resolve this with software changes.
The problem is centred on what the company describes as "uncommanded sudden wing drops during manoeuvring flight" which have come to light during the flight-test programme.
Ronald Harney, the F/A-18E/F flight-test team leader, describes the wing drop as "the toughest problem to date, at the heart of the tactical manoeuvre envelope".
Harney, speaking at the HAS Fighter Conference in London on 29-30 September, said that the problem occurs when the aircraft is being manoeuvred at between Mach 0.8 and 0.9 with 8-10¹ angle of attack. Part of the impact of this is to "-make tracking tasks difficult", he says.
The US company has looked at leading- and trailing-edge flap scheduling changes, which has resulted in "some success". Leading-edge snag extensions are also being considered, while Boeing will also look at cambered leading-edge flaps, vortex generators and stall strips in an attempt to overcome the stability problem.
Boeing has five F/A-18Es in the flight-test programme, along with two F/A-18F two-seaters. Three non-flying airframes, one for static, one for fatigue and one for drop testing have also been manufactured as part of the test programme. A non-flying airframe being used for land-based carrier emergency-barrier tests was damaged in September when the barrier failed.
Source: Flight International
