|(Not a demand for a cash payout for having coffee spilled on you by the stewardess in bumpy conditions)
Came across a discussion on Reno Racers where one design had the main spar too far back; the area in front of the main spar was big enough for the wing to be 'divergent' when flexing up and down in bumpy air. This meant the wing exaggerated bumps by flexing and 'flying' even more than it should.
Flex leads to shortened life on a metal skinned structure, but our fixed wings tend to be fabric over a steel or alloy tube frame; wing-warping is now regarded as old-fashioned and generally something to be dismissed as a pre first world blind alley, but you can't help wondering if the needs of even a modern microlight could make use of it?
The attached poor sketch tries to explain; by allowing the rear lift struts a little motion in response to bumps, the wing 'stress relieves' itself in rough air. You can engineer this pretty simply using a rocker beam at the base of the rear pair of lift struts. The problem is that the ailerons would then also 'fly' the wings in the opposite direction you want when operated, so you'd die.
This then led to the proposal that by the joystick actually be used to bias the rear rocker mounting, so that the wing would twist progressively along its length, rather like a propeller does. You get to dump all those fiddly cables and pulleys running around the cabin, and instead just have one ruddy great stiff tube along the middle of the cockpit floor to move the rocker beam for roll control.
Might be useful on aircraft such as the Skyranger, could then be feasible for the wing to fold back easily without undoing cables?
Sadly the flow of cranky ideas didn't stop there....
That centre rear pivot bearing supports half the weight of the aircraft, 225kilos for us and only half that on an SSDR. Enabling the rear centre pivot to rise and fall, against that weight, means you can vary the angle of incidence of the wing itself. This makes flaps, slow/fast flight and all sorts of other dodges possible, although losing the washout in slow flight would need expert input at the design stage.
So rugged, simple, easy to design and just possibly lighter than having flaps, ailerons and thier associated cables and pulley in the cabin and wing.
Wonder why no one has done it? Or have they?
"The young man knows the rules but the old man knows the exceptions”...Oliver Wendell Holmes