How did WWI biplane and triplane wings generate lift?

[ruko]

A plane works because of Bernoulli's principle the air flows faster on top
because of the shape of the wing thus creating a low pressure on top
and the high pressure on the bottom of the wing pushes the plane up , I mean yes it can climb by moving the aileron's .

OK, if it's wing shape resulting in less pressure on top than on the bottom, then how do they fly upside down? Ailerons do not control up and down movement. Elevators do that.

 

[Doggy Darb]

I was looking for information about biplanes when I can upon this forum.

There are a few reasons biplanes were popular during WWI. As we all know from the drag equation, drag increases with speed. At 100mph, drag is much lower than at 1200mph let alone 200mph, which was the speed being achieved when monoplanes became popular in combat. Lower drag forces resulting from lower speeds meant that it was not unpractical to add the additional drag of a second wing in exchange for the lift and agility it provides. Triplanes fell from favor because they restricted vision. As mentioned before, multiple wings are made into a truss. If you've ever seen any of these aircraft, you will be astonished that they are more like furniture than any vehicle you are familiar with. Monoplanes were better suited to endurance flights as they lacked the structure to withstand radical maneuvers and stunt flying.

Pressure differentials do play a part in lift. A wing is a baffle. Think of how water skis work; that is how a wing works. The air under the wing is exerting a pressure directly to the wing. If there is no angle of attack, there is normally not enough lift to generate flight. Ailerons, elevators, stabilators, elevons, flaps, and air brakes all work off of the same principle. They redirect the flow of air. Flaps generate more drag because they redirect air more radically, but they direct air downwards. This allows for slower speeds to generate sufficient lift. The force vector is more vertical. Stabilizers are horizontal in order to counter the moment that the wing imparts on the aircraft. If the stabilizer has the same angle of attack that the wing has, the aircraft would never leave the runway.

Airplanes fly upside down by "diving" up while inverted. The elevating mechanism is directing air upwards, driving the tail section down. This counters the downward velocity the aircraft would otherwise have. If an aircraft is inverted and no other control is exerted, the aircraft loses altitude.