Well there are lots of references to this subject on the net but few actually lead anywhere (Mind you I have learned a lot about all other types of flaps, their purpose and useage)--this is about the only direct ref. so far:-- 'The flaps on a Maule airplane can be selected negative, which then gives the best lift:drag ratio at a higher airspeed.' And this--the tech. name is Reflex flaps although negative works:-- As you say Dozer more for Gliders though the Maule & Seamax have it as an option 'Speed mode (reflex). Flaps or both flaps and ailerons at a small negative (up) angle reduces lift and drag by reducing the natural camber of the airfoil. You go faster.'