Best rate of climb speed occurs where the difference between available engine power and required power for level flight is greatest; this is max excess power. In a turbine, at slower speeds, available power will increase with speed at a faster rate than required power, so best rate of climb speed will be slightly greater than minimum power speed. Minimum sink rate occurs at the minimum power required to sustain flight speed, this gives best loiter time, max endurance.
Best angle of climb speed occurs where max thrust minus drag is greatest. Thrust does not vary much with speed, so max climb angle is obtained near minimum drag speed. Minimum glide angle will occur when the weight component acting in the direction of flight will just balance drag, for the most efficient operation this occurs at the minimum drag speed, that is where the least amount of weight is acting in the direction of flight. As stated minimum drag speed is the same as minimum glide angle which is the same as best angle climb speed. Minimum glide angle will give the greatest horizontal distance.
- confusing isn’t it.
