Winglets increase an aircraft's operating
efficiency by reducing induced drag
at the tips of the wings
Winglets increase the fuel efficiency of aircraft that have them.
Winglets are not absolutely required but many planes have winglets added to improve the aerodymanic efficiency of the wing.
to reduce drag
They are called winglets, the main function of the winglets is to reduce drag. Reducing drag increases speed and decreases fuel consumption, thereby extending range and saving money.
Thrust vectoring. The winglets are there for stability - if they were to try placing ailerons on the winglets, they'd likely be unable to withstand the force exerted on them by the missile moving at speeds of over Mach 2.
If this is in reference to winglets, they increase effective wing square area and thus add lift and can increase gliding or (Power off) range without materially adding drag.l That is the explanation I got from a museum official who is also a Glider Pilot, and winglets are common on advanced gliders.
I can't think of any cathedral-wing aircraft that DO use winglets. Spanwise flow on a cathedral wing would be flowing 'uphill' (inward) and would be interrupted by the fuselage.
The winglets work by reducing drag created by the vortices that are generated by a plane's wingtips. Aviation Partners Boeing estimates that its blended winglets for the 767-300ER will save up to 6.5 percent on fuel consumption, or a savings of roughly 500,000 gallons of jet fuel per aircraft per year for operators with the longest average sector lengths and highest aircraft utilization rates.
These are called winglets. They reduce drag therefore increase lift.
PUT THE WINGS UPWARD BEND THE ELEVATORS UP PUT SOME WINGLETS
Winglets descrease induced drag (drag from the production of lift) created by wing-tip vortices, simply turbulent airflow off the edge of the wing. So they do increase handling characteristics and fuel efficiency because of the increase in lift and decrease in drag. Hope this helped!
Winglets were invented in the 1950's by a Richard Whitcome. Answer: The man's name was Whitcomb, and he proposed it in the '70s (after the oil crisis). But he didn't invent them, he "simply" refined a previous idea from Hoerner (which WAS in the '50s), although the idea in one form another goes back even further (Lanchester, 1897).