Have you ever thrown a Frisbee? It flies because of four forces. These same four forces help an airplane fly. The four forces are lift, thrust, drag, and weight. As a Frisbee flies through the air, lift holds it up. You gave the Frisbee thrust with your arm. Drag from the air made the Frisbee slow down. Its weight brings the Frisbee back to Earth again.
You see them everyday: airplanes, jets, and helicopters, soaring, zooming, and even roaring through the skies. We may take flight for granted; yet, knowing the science behind it gives us a better understanding of the marvels of air travel.
Wings keep an airplane up in the air, but the four forces are what make this happen. They push a plane up, down, forward, or slow it down.
The Four Forces of Flight Keep This Plane Aloft
The way the four forces act on the airplane make the plane do different things. Each force has an opposite force that works against it. Lift works opposite of weight. Thrust works opposite of drag. When the forces are balanced, a plane flies in a level direction. The plane goes up if the forces of lift and thrust are more than gravity and drag. If gravity and drag are bigger than lift and thrust, the plane goes down. Just as drag holds something back as a response to wind flow, lift pushes something up. The air pressure is higher on the bottom side of a wing, so it is pushed upward.
See the following video paying attention to the technical vocabulary used here:
An airplane uses taxiways to taxi from one place on an airport to another; for example, when moving from a hangar to the runway. The term \”taxiing\” is not used for the accelerating run along a runway prior to takeoff, or the decelerating run immediately after landing, which are called the takeoff roll and landing rollout, respectively.
Taxiing is the movement of an aircraft on the ground, under its own power, in contrast to towing or pushback where the aircraft is moved by a tug. The aircraft usually moves on wheels, but the term also includes aircraft with skis or floats (for water-based travel).
A taxiway is a path for aircraft at an airport connecting runways with aprons, hangars, terminals and other facilities. They mostly have a hard surface such as asphalt or concrete, although smaller general aviation airports sometimes use gravel or grass.
Most airports do not have a specific speed limit for taxiing (though some do). There is a general rule on safe speed based on obstacles. Operators and aircraft manufacturers might have limits. Typical taxi speeds are 20–30 knots (37–56 km/h; 23–35 mph).
When taxiing, aircraft travel slowly. This ensures that they can be stopped quickly and do not risk wheel damage on larger aircraft if they accidentally turn off the paved surface. Taxi speeds are typically 30 to 35 km/h (16 to 19 kn).
Takeoff is the phase of flight in which an aerospace vehicle leaves the ground and becomes airborne. For aircraft traveling vertically, this is known as liftoff.
For aircraft that take off horizontally, this usually involves starting with a transition from moving along the ground on a runway. For balloons, helicopters and some specialized fixed-wing aircraft (VTOL aircraft such as the Harrier), no runway is needed.
The operation of increasing the altitude of an aircraft. It is also the logical phase of a typical flight (the climb phase or climbout) following takeoff and preceding the cruise. During the climb phase there is an increase in altitude to a predetermined level. The opposite of a climb is a descent.
Cruise is a flight phase that occurs when the aircraft levels after a climb to a set altitude and before it begins to descend. Cruising usually takes the majority of a flight, and it may include changes in heading (direction of flight) at a constant airspeed and altitude.
For most passenger aircraft, the cruise phase consumes most of the aircraft\’s fuel. This lightens the aircraft and raises the optimum altitude for fuel economy. For traffic control reasons it is usually necessary for an aircraft to stay at the cleared flight level. On long-haul flights, the pilot may ask air traffic control to climb from one flight level to a higher one, in a maneuver known as step climb.
Commercial or passenger aircraft are usually designed for optimum performance at their cruise speed (VC). Combustion engines have an optimum efficiency level for fuel consumption and power output. Commercial or passenger aircraft are usually designed for optimum performance at their cruise speed (VC). Combustion engines have an optimum efficiency level for fuel consumption and power output.
A descent during air travel is any portion where an aircraft decreases altitude, and is the opposite of an ascent or climb. Descents are part of normal procedures, but also occur during emergencies, such as rapid or explosive decompression, forcing an emergency descent to below 3,000 m (10,000 ft) and preferably below 2,400 m (8,000 ft), respectively the maximum temporary safe altitude for an unpressurized aircraft and the maximum safe altitude for extended duration.
Intentional descents might be undertaken to land, avoid other air traffic or poor flight conditions (turbulence, icing conditions, or bad weather), clouds (particularly under visual flight rules), to see something lower, to enter warmer air, or to take advantage of wind direction of a different altitude, particularly with balloons.
Normal descents take place at a constant airspeed and constant angle of descent (3 degree final approach at most airports). The pilot controls the angle of descent by varying engine power and pitch angle (lowering the nose) to keep the airspeed constant.
A landing maneuver in which a significant component of the prevailing wind is perpendicular to the runway center line.
In aeronautics, the final approach (also called the final leg and final approach leg) is the last leg in an aircraft\’s approach to landing, when the aircraft is lined up with the runway and descending for landing. In aviation radio terminology, it is often shortened to \”final\”.
The final approach (also called the final leg and final approach leg) is the last leg in an aircraft\’s approach to landing, when the aircraft is lined up with the runway and descending for landing.
This is the last part of flight. The fact of an aircraft arriving on the ground.
PAPI: precision approach path indicator: a visual aid that provides guidance to help a pilot during final approach.
APRON: the area of an airport where aircraft are parked, unloaded or loaded, refueled, boarded or maintained.