Glide:
The Glide ratio of an aircraft is the distance of forward travel divided by the altitude lost in that distance. The glide ratio is affected by all of the four fundamental forces that act on an aircraft in flight - lift, drag, weight and thrust. If all these factors remain constant, the glide ratio will not change. However, wind velocity is a very important practical influence on gliding distance over the surface. With a tailwind, the glide distance achieved will be increased because of increased ground speed whereas with a headwind, it will be reduced because of the consequently slower ground speed. Variations in aircraft weight do not affect the glide angle provided that the correct airspeed is flown. Since it is the lift over drag (L/D) ratio that determines the gliding range, weight will not affect it. The glide ratio is based only on the relationship of the aerodynamic forces acting on the aircraft. The only effect weight has is to vary the time the aircraft will glide for. The heavier the aircraft is, the higher the airspeed must be to obtain the same glide ratio. If two aircraft have the same L/D ratio but different weights and start a glide from the same altitude, the heavier aircraft gliding at a higher airspeed will arrive at the same touchdown point in a shorter time. Both aircraft will cover the same distance but the lighter one will take a longer time to do so. Drag will increase if the landing gear or flaps are extended and the airspeed will then decrease unless the pitch attitude is reduced. When pitch is reduced, the glide angle increases and the distance traveled will reduce. The best speed for range corresponds to an angle of attack which gives the best lift-to-drag ratio. Any change in the gliding airspeed will result in a proportionate change in glide ratio. At any speed, other than the best glide speed, the glide ratio will change. When descending at a speed less than the best glide speed, induced drag increases. When descending at a speed greater than the best glide speed, parasitic drag increases. In either case, the rate of descent will increase.
Climb:
Increasing the power by advancing the throttle produces a marked difference in the rate of climb. Climb depends upon the reserve power or thrust. Reserve power is the available power over and above that required to maintain horizontal flight at a given speed. Thus, if an airplane is equipped with an engine which produces 200 total available horsepower and the airplane requires only 130 horsepower at a certain level flight speed, the power available for climb is 70 horsepower. Although we sometimes use the terms "power" and "thrust" interchangeably, erroneously implying that they are synonymous, it is well to distinguish between the two when discussing climb performance. Work is the product of a force moving through a distance and is usually independent of time. Work is measured by several standards, the most common unit is called a "foot-pound." If a 1 pound mass is raised 1 foot, a work unit of 1 foot-pound has been performed. The common unit of mechanical power is horsepower; one horsepower is work equivalent to lifting 33,000 pounds a vertical distance of 1 foot in 1 minute. The term "power," implies work rate or units of work per unit of time, and as such is a function of the speed at which the force is developed. "Thrust," also a function of work, means the force which imparts a change in the velocity of a mass. This force is measured in pounds but has no element of time or rate. It can be said then, that during a steady climb, the rate of climb is a function of excess thrust.
