Fly Lah!

can angle of incident be change during flight?

No, On fixed-wing aircraft, angle of incidence is the angle between the chord line of the wing where the wing is mounted to the fuselage and the longitudinal axis of the fuselage. The angle of incidence is fixed in the design of the aircraft by the mounting of the wing to the fuselage.

Cheers

But Angle of Attack can be changed? Right?

michyiki wrote:But Angle of Attack can be changed? Right?

Yes, it can be changed when you pitch the Aircraft up or down. Its the angle between the chord line and the relative air flow of the aerofoil.

The definitions given by Maverick are what we expect as basic answers from students. However angle of incidence as per the stated definition is also named "rigging incidence" it is the basic angle between the wing and the longitudinal axis as per the design. But when you extend the flaps some are considering that there is a change in the angle of incidence as they make the difference with "rigging incidence" and "incidence", however this is an advanced stage and may conduct to confusion for students, so I suggest to stick to the basics.
The two basic parameters for flying are the angle of Attack and the speed as both are factors in the formula of Lift. When you change your "attitude", your A of A varies.
It is important to make the difference between "Attitude", Angle of Attack and incidence.
Good Studies

Hey thanks for elaborating further on the topic. I admit that I'm just still a student even though I've already graduated. I'm always happy to learn new things about aviation.. It keeps me on my toes..

Cheers & Thanks Again Terengganu01!

Air flow above the aerofoil flows from wingtip to the root while air flow below the aerofoil flows from the root to the wingtip, right?

Then wat about the vortex? How does vortex form? Is it flowing at the top of the aerofoil?

Thx for answering~

good Michyiki,

As you say air flow on the upper surface has a component of speed "inward", and on the lower surface"outward". The difference of pressures (high pressure on the lower surface, low pressure on the upper surface - see Bernouilli) at the tip create a trend of air flow from lower surface to upper surface, so a movement of air flow from down to up rolling around the tip. This is what is creating the vortices. Winglets are working on this and a "positive drag" is get back from winglet effect: winglets reduce the drag.
However there is an important torque on the winglets and structural reinforcements are required.
Good studies
Terengganu01

Thx for the explanation So it means that the upwash creates circulation whereby vortex are created from the root to the tip of the wing. If winglets are created to reduce the drag, the effect of vortex from the winglet will be cancelled or continue exist as vortex or turbulence? Learning planes apart with winglets and without winglets, is it necessary to build winglets at the tip of the airplane? And the design of the winglets will alter the vortex produced?

Thanks for the answering and Sorry if some of the statements is wrong

The winglets will reduce the drag but does not cancel the effect of the vortex in total but reduces it in size..
It is not necessary to build winglets but it does help economize fuel consumption. That's the main reason why they developed the winglets..