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The FAA states "The height–velocity diagram or H/V curve is a graph charting the safe/unsafe flight profiles relevant to a specific helicopter. As operation outside the safe area of the chart can be fatal in the event of a power or transmission failure it is sometimes referred to as the dead man's curve."
The speed to fly is the optimum speed through sinking or rising air mass to achieve either the furthest glide, or fastest average cross-country speed. [1] Most speed to fly setups use units of either airspeed in kilometers per hour (km/h) and climb rate in meters per second (m/s), or airspeed in knots (kn) and climb rate in feet per minute (ft ...
The corresponding maximum range condition is the maximum of C L 3/2 /C D, at C L 2 = 3.C D0 /K, and so the optimum speed is 244 km/h (152 mph). The effects of the approximation C L0 = 0 are less than 5%; of course, with a finite C L0 = 0.1, the analytic and graphical methods give the same results.
Graphs of C L and C D vs. speed are referred to as drag curves. Speed is shown increasing from left to right. The lift/drag ratio is given by the slope from the origin to some point on the curve and so the maximum L/D ratio does not occur at the point of least drag coefficient, the leftmost point. Instead, it occurs at a slightly greater speed.
Should be attained by a gross height of 400 ft (120 m). [10] V A: Design maneuvering speed. This is the speed above which it is unwise to make full application of any single flight control (or "pull to the stops") as it may generate a force greater than the aircraft's structural limitations. [7] [8] [9] [11] V at
For instance a Cessna 150 at 2,500-foot (760 m) altitude and 90-mile-per-hour (140 km/h) speed needs about 60 horsepower (45 kW) to fly straight and level. The C150 is normally equipped with a 100-horsepower (75 kW) engine, so in this particular case the plane has 40 horsepower (30 kW) of extra power.
At maximum weight it has a V Y of 75 kn (139 km/h) indicated airspeed [4] providing a rate of climb of 721 ft/min (3.66 m/s). Rate of climb at maximum power for a small aircraft is typically specified in its normal operating procedures but for large jet airliners it is usually mentioned in emergency operating procedures.
The logarithmic term with weight ratios is replaced by the direct ratio between / = where is the energy per mass of the battery (e.g. 150-200 Wh/kg for Li-ion batteries), the total efficiency (typically 0.7-0.8 for batteries, motor, gearbox and propeller), / lift over drag (typically around 18), and the weight ratio / typically around 0.3.