- So far the lift is concerned, it increases as we increase the angle (provided the air speed remains constant) but only up to certain limit; after this it begins to fall off.
- The actual amount of lift given by wing when this maximum limit is reached varies with shape of aerofoil section.
- Most of the wings, whatever their aerofoil shape and whatever the air speed, reach their maximum lift at about 15deg to 20deg.
- After certain angle the wing loses its lift and drag dominates. This phenomenon is called stalling.
- Aspect Ratio is a measure of how long and slender a wing is from tip to tip.
- The Aspect Ratio of a wing is defined to be the square of the span divided by the wing area and is given the symbol AR.
- The formula is simplified for a rectangular wing, as being the ratio of the span to the chord length as shown on the figure below.
10. Wing Dihedral
- Wing Dihedral refers to the angle of wing panels as seen from the aircraft's front view.
- Dihedral is added to the wings for roll stability; a wing with some Dihedral will naturally return to its original position if it is subject to a briefly slight roll displacement.
- Most large airliner wings are designed with Dihedral.
- On the contrary the highly maneuverable fighter planes have no Dihedral.
- In fact, some fighter aircraft have the wing tips lower than the roots, giving the aircraft a high roll rate.
- A negative Dihedral angle is called Anhedral.
|See the Dihedral of 5 deg in the above given Izicraft-400 trainer aircraft.|