Search results
Results from the WOW.Com Content Network
This point of view has a problem: if suffice to take the angle for which the ray has a tangent point of lowest altitude. For instance with the case of a source at 5 km altitude, of nominal elevation angle −0.5-degree and the target is at 30 km altitude; the attenuation found by the boundary value method is 11.33 dB.
In these equations, g 0, M and R * are each single-valued constants, while ρ, L, T and h are multi-valued constants in accordance with the table below. The values used for M, g 0 and R * are in accordance with the U.S. Standard Atmosphere, 1976, and that the value for R * in particular does not agree with standard values for this constant. [2]
When a hovering rotor is near the ground the downward flow of air through the rotor is reduced to zero at the ground. This condition is transferred up to the disc through pressure changes in the wake which decreases the inflow to the rotor for a given disc loading, which is rotor thrust for each square foot of its area.
The 2-ray ground reflected model may be thought as a case of multi-slope model with break point at critical distance with slope 20 dB/decade before critical distance and slope of 40 dB/decade after the critical distance. Using the free-space and two-ray model above, the propagation path loss can be expressed as
g = acceleration due to gravity at the current location The pressure (force per unit area) at a given altitude is a result of the weight of the overlying atmosphere. If at a height of z the atmosphere has density ρ and pressure P , then moving upwards an infinitesimally small height dz will decrease the pressure by amount dP , equal to the ...
However, its units are traditionally referred to as g, because of the relation between load factor and apparent acceleration of gravity felt on board the aircraft. A load factor of one, or 1 g, represents conditions in straight and level flight, where the lift is equal to the weight.
The term "Kármán line" was invented by Andrew G. Haley in a 1959 paper, [20] based on the chart in von Kármán's 1956 paper, but Haley acknowledged that the 275,000 feet (52.08 mi; 83.82 km) limit was theoretical and would change as technology improved, as the minimum speed in von Kármán's calculations was based on the speed-to-weight ...
The environmental lapse rate (ELR), is the actual rate of decrease of temperature with altitude in the atmosphere at a given time and location. [6]The ELR is the observed lapse rate, and is to be distinguished from the adiabatic lapse rate which is a theoretical construct.