Aerodynamics for Naval Aviators
Instructions:-
Explain how to read the following diagram, again assuming you are trying to instruct someone unfamiliar with the material. You can utilize annotations in the diagram (diagram also uploaded as a picture into your team’s files section and available as Fig. 1.13, p. 31, in “Aerodynamics for Naval Aviators”) or even screen-capture/-record a full instructional presentation video or Powerpoint if you like. The choice of instructional style is yours, but make sure to highlight all main points for understanding the presented information.
As a minimum, address the following:
– Stall conditions (e.g., CLmax; Associated AOA)
– Glide conditions (e.g., associated, AOA, resultant glide ratio)
– L/D (e.g., value, associated AOA)
Soltion
Aerodynamics for Naval Aviators
The optimization of drag and lift characteristics ensures the design of an effective airfoil shape depending on the mission of an aircraft. Understanding the changes occurring in flowing air past the wing and the influence of the airfoil shape on the lift and drag is critical. Reading the airfoil data is essential to understanding lift-drag ratios.
The reading is simple but requires close attention to details. First, the equation for calculating drag is; D = CDqS, where D is the drag in lbs, CD is the drag coefficient, q is the dynamic pressure, and S is the wing surface area (U.S. Navy Naval Air Systems Command; Hugh Harrison Hunt, 2016).
In reading the chart, understanding the CL, CD and L/D (lift-drag ratio) is necessary. Taking the reading for specific angles of attack using the drag and lift data gives the proportions of CD and CL whose division CL/CD gives the lift-drag ratio (L/D). The L/D as plotted against the angle of attack shows an increase of L/D to its maximum and a decrease.
The CL curve shows the lift-coefficient.
The CD curve represents the drag coefficient, while
The L/D curve is the ratio of CL to the CD.
The CL and CD give dimensionless.
CL reading shows that at zero AoA, Lift is zero but Drag is .0200 as shown on the CD scale.
To read the CL max, mark a point on the highest point of the CL and take the AoA of that point by making a straight line downwards to the AOA scale. In this graph, the CL Max shows an AoA of 20. While a straight line from the maximum value of CL gives a 1.5 on the CL scale. The stall conditions of CL give an AoA of 20.8 and a CL measure of 1.22.
Reading the L/D shows that at zero AoA, L/D is zero while the maximum L/D stands at AoA of 6. Moreover, taking the stalled reading of L/D requires making a straight line downwards to the AoA X-axis, which gives 18.6.
At L/DMax the glide range is at maximum power-off (Hurt, 1965).
References
Hurt, H. H. (1965). Aerodynamics for naval aviators. University of Southern Carolina: Naval Airs Systems Command. Retrieved from https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/media/00-80T-80.pdf
U.S. Navy Naval Air Systems Command; Hugh Harrison Hunt. (2016). Aerodynamics for Naval Aviators: NAVWEPS 00-80T-80. New York: Ravenio Books.