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How is antenna drag calculated?
The drag coefficient of the antenna with the corresponding length can be calculated based on the wind load measured through the wind tunnel test. The drag coefficient and wind load of antennas with different lengths can be calculated by multiplying the drag coefficient by the end- effect factor.
How is antenna wind load calculated?
The generic formula for calculating wind load is F = A x P x Cd, where F is the wind load, A is the surface area of the antenna (usually given in square feet), P is the wind pressure (calculated from another formula) and Cd is the drag coefficient. …
How do you calculate tower loading?
or: T = 20.63 square feet (effective tower wind loading applied at the top). Thus, at 70 mph, the total force on the tower and antenna is K x (30 + 20.63) x 70 x 70, or K x 248,000. Similarly, at 90 mph, we get K x (10 + 20.63) x 90 x 90, or K x 248,000.
How do you calculate wind load?
Armed with pressure and drag data, you can find the wind load using the following formula: force = area x pressure x Cd. Using the example of a flat section of a structure, the area – or length x width – can be set to 1 square foot, resulting in a wind load of 1 x 25.6 x 2 = 51.2 psf for a 100-mph wind.
How are antennas used to improve aerodynamics in aircraft?
Antennas sticking out of an aircraft obviously increase profile drag, but the folks who design antennas have done a lot to improve aerodynamics: High performance aircraft can have antennas mounted inside of fiberglass components like wingtips, and flush-mounte antennas are available for transponders and DME equipment.
How is the drag of an antenna measured?
Drag is defined as: D = 1 2 C D ρ V 2 A Thus, say you have a 0.01 m wide antenna 0.25 m long, for an aircraft moving at 50 m/s. At sea level conditions, air density ρ = 1.225 k g / m 3.
Where are the communication antennas on an airplane?
Communication antennas Communication antennas are basic in operation. Each com transmitter has its own antenna, mostly for redundancy. They can be mounted on either the top or bottom of the aircraft, but each installation is susceptible to shadowing from the fuselage.
Why are two GPS antennas mounted on the fuselage?
A single nav antenna almost always feeds mulitple nav receivers and sometimes the glideslope as well. Therefore, a failure in the nav antenna system would cause multiple systems to malfunction. Two GPS antennas are mounted on top of this fuselage; an antenna for each receiver provides redundancy. Photo by Chris Rose.