User:Acmenconi/sandbox

= Air Brakes (aeronautics) =

Introduction
An air brake is a panel conforming the shape of an aircraft that can be opened with hydraulic pressure in order to create drag, similar to spoilers which are on the edges of the aircrafts wings and open in an upward position forcing the plane towards the ground. Air brake used in any circumstance when the aircraft needs to reduce its airspeed, however spoilers are only able to be opened when the airplane is approaching the runway and about to touch down. Lift dumpers, a type of air brake, is mounted on the top of a fuselage. When the panel is opened, it acts as a small spoiler, gently pushing the aircraft down. The air speed reducing devices found on the wings of aircraft, often called flaps have several different uses and designs. Most all flaps provide some amount of lift in addition to drag either for taking off or for keeping the nose up when landing. The slotted and fowler flaps are “both designed to physically increase the overall surface area of the wing, literally making the wing bigger”. In slotted flaps, there are at least one open gap or slot in between the actual fixed wing of the aircraft and the adjustable flap. With these types, air passing underneath the wing of the aircraft is allowed to escape up through the slot due to the position of the flap tilting down. This directional flow of air and the extra surface area underneath the wing causes slight downforce pressure as well as reduced airspeed. Used more temporarily and for lower amounts of time than typical flaps, spoilers are similar to those seen on race cars. Spoilers are essentially an upside-down wing or lip causing downforce and drag. Spoilers on aircraft are only used when landing, not in midair, often with conjunction of slotted flaps. Together the flaps and spoiler disrupt the smooth flow of the wind and force it up and down across different surfaces protruding from or through the wing, causing a large amount of wind resistance and drag reducing overall air speed, acting as an airbrake.

History
For several decades, almost ever sense the fixed wing aircraft was invented, man strived to make these craft faster than before. A universal goal for all manufacturers for some time, was reaching the speed of sound. Apart from an engine that could propel an aircraft upwards of 740 miles per hour and keeping the plane from breaking apart by the stress, one of the main concerns was keeping the plane in stable flight and being able to return to normal flying speeds with a stronger breaking system. The air brake systems used in the 1930’s was again simple flaps manually controlled by a lever in the cockpit and mechanical devices running through the wings, however, in order for speed brakes to work at a speed of 740 miles per hour, the brakes must be mounted on the fuselage for better wing control, and must be operated through some kind of dampener or hydraulic system so the piolet could physically pull a lever to create an excessive amount of wind resistance. The concept of fuselage mounted air brake or speed brakes spread throughout the 1930s, eventually being seen more in the 1940s. In the 30s, pilots were thought to land with their nose at a 45-degree angle for short landings. With this method, “the drag or resistance is increased by 300 percent, and the distance required to land is cut down to one third of the usual stopping distance”. An alternate way to drastically reduce speed was developed without causing the pilot to lose sight of what is ahead of him. The new air braking systems was an additional wing mounted brake on the wings that opened in two directions at the same time. This wing mounted design produced more drag than the conceptual fuselage design at the time resulting in a quicker reduction in air speed. This allowed the surface area of using flaps for landing to be increased 100 percent. This also allowed the pilot to be able to see the landing strip in front of his aircraft due to there being less of a need to tilt upward at a 45-degree angle at close to stalling speeds. The rate of deceleration and foot pounds of force applied to each brake is dependent upon where the brake is located. Upper and lower surface flaps located along the wings provide the steadiest curve comparing force applied and deceleration rate, however, experience much more stress at theoretical higher speeds. Spoilers on the wings experience less force, but do not reduce the speed of the aircraft at higher speeds. Brake plates mounted upon the fuselage of an aircraft experience much more force applied per square inch but also reduce the speed of the aircraft much faster at higher speeds when used with some wing mounted assisting brake. With panels mounted along the body of the plane, the actual brake plates are allowed to be made thicker to experience the greater amount of force applied to them. This piece also reveals different deceleration rates at a vertical dive with air speeds just under 300 miles per hour at different air brakes opened to different angles at different altitudes. The issue is, theoretically at higher altitudes, air brakes will be less and less useful as simply creating more surface area on the aircraft will still not have enough air resistance due to the thinner atmosphere. According to their technology at the time, the drag coefficient for a vertical drive at 40,000 feet or above is too much for a simple air brake to handle. In pre 1950s British research, the different shapes of air brakes and flaps being tested produced different drag patterns. The use of two flaps per wing on military fighter aircraft, one of which opening up and the other opening down, will allow the most rapid deceleration while control of the plane is maintained. Having flaps open up creates a downforce in addition to reducing air speed, pushing the plane towards the ground, similarly having flaps only open downward pushed the nose of the aircraft into the air. Having air brakes on the wings both opening up and down, cancels out the opposite up and down forces creating resistance only forcing the craft to decelerate. At this time, different styles of brake panels were being experimented with for newer jet aircraft. A flat platted panel would provide the most air resistance thus reducing the air speed the fastest, however, the amount of stress and pressure on that plate is greatly increased, and not suitable at the time for high speed flights. At high levels of speed seen from a jet aircraft, these forces could be too much for the brakes to handle. Additionally, with no air passage through the brake panels, the slightest change in air pressure or turbulence could through off the balance of the craft. With slotted or perforated brake plates, the distortion of air flow is greatly reduced, and the aircraft therefore has a higher level of control when braking at high speeds at the cost of the rate of deceleration. The plates with the most open space allows the most control and least amount of air flow disturbance. This leaves different brake plate options for different aircraft with different design purposes and usage.

Scientific Principles
Principles such as plotting semi-empirical relations in order to estimate aircraft component parasite drag are necessary for developing and understanding the physical properties behind flight. Essentially, everything on the aircraft is taken into consideration for its size, surface area and amount of drag created. Everything from the location and size of the jet engines, to the shape of the fuselage, to wings and winglets and flaps are all noted, and equations are derived to develop an idea on the drag being created. Specifically, on the subject of air brakes and the intentional act of reducing air speed, slotted fowler flaps are examined, and a graph is constructed on the angle degree in which the flaps are tilted and the amount of lift and drag created by the distortion in the direction of air flow. Additionally, to reduce air speed, “whether in combat or landing, flat plates are used which are attached to the fuselage and shaped to its geometric contour when retracted”. In the circumstance of air brakes used during subsonic flight, the equation for drag would be CDπ_brake=1.2-2.0 (with an average of 1.6).

Technology
There are several styles of wing-based flaps and spoilers found on today’s aircrafts that greatly resemble some of the first air speed brakes invented. Slotted and fowler flaps are “both designed to physically increase the overall surface area of the wing, literally making the wing bigger”. In slotted flaps, there at least one open gap or slot in between the actual fixed wind of the aircraft and the adjustable flap. With these types, air passing underneath the wing of the aircraft is allowed to escape up through the slot due to the position of the flap tilting down. This directional flow of air and the extra surface area underneath the wing causes slight downforce pressure as well as reduced airspeed. Spoilers are often used in larger aircraft and used more temporarily and for less amounts of time than typical flaps as they are designed to not only slow the craft down, but it creates downforce pushing the plane towards the ground. Spoilers are essentially an upside-down wing where the length on the top of the wing exceeds that of the bottom, resulting in the high air pressure on top of the spoiler to push down towards that of lower air pressure underneath. Lips are also used for the air running across the top of a wing to be forced further up, creating more drag and also pushing the plane closer to the ground. Spoilers on aircraft are only used when landing, not in midair, often with conjunction of slotted flaps. Together the flaps and spoiler disrupt the smooth flow of the wind and force it up and down across different surfaces protruding from or through the wing, causing a large amount of wind resistance and drag reducing overall air speed, acting as an airbrake.