angle of attack


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angle of attack

[′aŋ·gəl əv ə′tak]
(aerospace engineering)
The angle between a reference line which is fixed with respect to an airframe (usually the longitudinal axis) and the direction of movement of the body.
(mining engineering)
The angle in a mine fan made by the direction of air approach and the chord of the aerofoil section.

Angle of Attack

 

the angle between the direction of trans-lational motion of a body and some characteristic direction on the body. The characteristic direction may be, for example, a chord of an airplane wing or the axis of symmetry of a projectile or a rocket.

angle of attack

angle of attackclick for a larger image
Angle of attack is the angle between the wing chord plane and the relative air flow.
The acute angle between the chord line and the relative airflow. Often referred to as an angle of incidence—which it is not. The angle of attack should not be confused with the pitch angle or attitude of aircraft, which are angles relative to the horizontal while the angle of attack is in respect to the relative airflow. It is referred to also as alpha (α).
References in periodicals archive ?
The system was designed on an axis, on which the gear responsible for changing the angle of attack of the hydrofoil is mounted.
By comparing the mean pressure distribution (Figure 14) at angle of attack [alpha] = 165[degrees], it is observed how the URANS results modify the mean base pressure to provide a better accuracy compared to experimental data on [c.sub.l] and [c.sub.d].
For the grids with solidity b/t < 0.5, the effect of hysteresis occurs when angle of attack i' exceeds the critical value [i.sub.KP] by 10-20%, which is in this case during transition of the grid from supercritical modes of flow to subcritical (non-separated) angles of attack due to which the initial non-separated flow is recovered.
9-10, as for an angle of attack of -8[degrees] the NACA 4421 airfoil has a flow separation in the upper surface at 0.72 based unit chord position but the flow separation disappears for every modified airfoil.
To keep the same exit pressure, there is more requirement of pressure at any axial locations while using the vortex generator and it increases with the increase in the angle of attack. The pressure difference for the wing at 20[degrees] is 10.79 % more as compare to the plain duct.
Moreover, the values of [C.sub.L] changed with the thumb position at angles of attack of 0[degrees] and 45[degrees], although at an angle of attack of 90[degrees] the values of the different thumb positions were identical.
Frink makes the angle of attack issue easy to solve for the operator with the use of a manual adjustment telescopic moldboard brace.
This "canard" would mimic a dragonfly's technique by sharply shifting its angle of attack to generate vortices to order.
The angle of attack indicator is what determines how much the plane's nose is tilted.
A preliminary report on the Lion Air Flight 610 accident blamed it in part on a faulty angle of attack sensor that triggered the MCAS system and automatically forced the plane's nose down.
After all, what single word, if any, concisely describes what happens when air flows over an airfoil at low angles of attack but then separates and stops flowing as that angle of attack exceeds a specific value?
For UAVs with flying wing configurations that are difficult to be controlled in the longitudinal direction, ground effects exert significant influences on manipulation design for safe take-off, therefore, in view of UAVs with medium-aspect-ratio flying wing configurations, it is necessary to study the characteristics of ground effect during take-off and find accurate relationships between longitudinal aerodynamic characteristics with height from the ground, take-off velocity, and angle of attack.