The Structure of the Glider - Assignment Example

Engineering and construction: Glider Glider A glider is normally a unique type of aircraft without an engine. There are various kinds of gliders with the most common being paper gliders and Styrofoam toy or Balsa wood gliders; which are cheap vehicle for students to have a good time as they learn aerodynamics basics. Hang-gliders on the other hand are normally piloted aircrafts with cloth wings as well as minimal structure. However, some hang-gliders appear like kites that are piloted, whereas others look like maneuverable parachutes. For instance, sailplanes normally are gliders that are piloted and have typical aircraft parts, construction as well as flight control systems with no engine. Additionally, the Space Shuttle re-enters the earth’s atmosphere as a glider. In the early 1900s, the Wright Brothers also acquired invaluable piloting experience via a series of glider flights (Barnaby, 1930). A glider usually has got 3 forces acting on it while in flight in comparison with 4 forces that normally act on an aircraft that is powered. Both kinds of aircrafts are all subjected to drag, weight, and lift forces. For the powered craft, there is the engine thrust that opposes the drag; however, there is no thrust for glider. A glider must generate lift so as to oppose its own weight for it to fly. For lift to be generated, a glider ought to move via the air. A glider’s motion via the air produces drag. In the case of an aircraft that is powered, the drag is opposed by the engine’s thrust; however, the glider lacks an engine to produce thrust. With nothing to oppose the drag, a glider will rapidly slow down till it can no longer produce adequate lift to resist its weight, and falls down to the ground finally (Barnaby, 1930). For balsa gliders and paper airplanes, the aircraft is initially given velocity by way of throwing. However, big balsa gliders make use of catapult prepared from rubber bands plus a tow line to offer velocity as well as some preliminary altitude. For the hang-glider ,they usually start by running and jumping off from the side of a cliff or a hill so as to start going. On the other hand, most sailplanes and hang-gliders are towed uphill by an aircraft that is powered and then released so as to start gliding. The powered airplane pulling the glider uphill provides the glider with the required quantity of potential energy. It is this difference in potential energy that is traded by the glider from an altitude that is high to the one that is low, producing kinetic energy in the process, resulting in velocity for the glider. Normally a glider is at all times sliding relative to the air in which it is flying. A glider is usually designed to be extremely efficient, to slide at a very slow speed. If a pilot is able to find a pocket of air rising more rapidly than the glider is sliding, then it can in fact gain in altitude, increasing further its potential energy. During the early stages, gliders did not have a cockpit; pilot used to sit on a tiny seat situated just to the fore of the wing. Generally such gliders were referred to as primary gliders. These gliders normally were launched especially from hill tops even though they were able to do short hops on the ground as they were being towed by a vehicle. For gliders to fly more efficiently than primary ones, designs have been done that reduce drag. Currently, gliders are equipped with very narrow, smooth fuselages together with extremely narrow wings having an elevated aspect ratio as well as winglets. Majority of the early gliders were built using wood fastened with metal, stays as well as control cables. Later on, fuselages built of steel tube covered with fabric were joined to wood together with fabric wings for strength and lightness. Modern materials, for instance, Kevlar, fiber glass and carbon fiber have ever since been utilized together with computer-aided design so as to enhance performance. Glass fiber is especially used extensively due to its capability of providing a smooth external finish and high ratio of strength to weight, thus reducing drag. Additionally, drag has also been substantially reduced by additional aerodynamic shapes as well as retractable undercarriages. Some gliders are also fitted with flaps onto the wings’ trailing edges so as to reduce drag from the glider’s tail plane at any given speed (Pallis, 1999). With every passing generation of new materials together with the enhancements being done in aerodynamics, gliders’ performance has increased tremendously. A glide ratio is used in measurement of performance and a 30:1 ratio implies that when the air is smooth a glider is capable of travelling 30 metres while it loses just a single meter of height. Balsa wood gliders are most efficient because the wood’s ratio of strength –to-weight is quite suitable for flying. Balsa wood is also able to build gliders that fly in an entirely realistic manner. In addition, Balsa wood, absorbs vibration and shock well as well as can be cut easily, glued, and shaped with basic hand tools (Pallis, 1999). During the early days of glider builders normally utilized non-tapered, stubby and non-sweptback wings. Wing tails were rounded whereas tail sections generally were of a square outline, utilizing no airfoil, but square segments all through. Glider finishing was not regarded of any significance. Most gliders therefore had no finishing at all and sandpaper was rarely used (Weitner, 1938).All these factors had a major impact upon the gliders’ ability to fly and flights of 30 seconds were unlikely because 40 feet height were rarely achieved. Glider builders soon realized that to attain long range distances; gliders’ wooden surfaces had to be smoothened; something which considerably improved the glide. In spite of this, builders realized that what in fact was needed to achieve higher height was on the throw. Builders started experimenting with sweepback, various span moment arms, streamlined surfaces and fine finishes. All these factors turned the glider into a polished, sleek ship able of attaining 100 feet or more of height on launch, requiring great strength during construction. This great stress needed remarkably great strength especially where the wing was joined to the fuselage. This necessitated use of tough layer of cement. Experiments are still being conducted to discover the characteristics to utilize in designing the glider which finally will lead to the closest possible ‘ideal’ design (Pallis, 1999). It has been discovered that sweepback increases the height gained on throwing as well as all round stability, a feature that is being used in majority of current models. This characteristic brings the glider’s center of gravity backwards, presenting a more evenly distributed aft and fore weights; requiring only less weight for balancing purposes. For this sweepback to be obtained, the central section of half the wing of the glider is usually squared off. Measurement is done of around 5/8-inch alongside the edge trail towards the wing’s tip. A line is then drawn from this point to the apex of the right slant at the wing’s foremost edge; it is alongside this line normally, drawing of the cutting edge is done. There is replication of this process usually on the wing’s other half, thus finishing the entire operation. Cementing of the 2 halves is then done, forming an estimated 18 degree sweepback on every side. An arrangement such as this; between 3 and 4 inches of dihedral, normally, on a 20 inch wing proved to be the most efficient (Weitner, 1938). It is important to also note that it does not matter the length of the moment arm is to be employed. This is because both short as well as long moment arms are endowed with their advantages as well as disadvantages respectively. For instance, a disturbing force normally has a superior impact on an arm that is short as compared to one that is long. A long moment is slow to respond to stabilizing forces and thus loses its earlier advantage to a short one. However, on throwing, a glider with short moment arm recovers more rapidly due to stabilizing properties, whereas a longer moment ship usually attains more height before it finally recovers fully, going into a straight glide. For balsa wood gliders therefore it is up to the designer plus his experience to come up with the best length arm to be utilized on his/her ship (Weitner, 1938). References Brain, M., & Adkins, B. (2014). How Gliders Work. How stuff works , np. Federal Administration Handbook, Glider Flying Handbook, 2007, Sky horse Publishing Inc Jani, P. (1999). The Big Book of Air and Space Flight Activities. New York,NY: McGraw-Hill. Ralph, B. (1930). Gliders and Gliding:Design Principles,Structural Features,and Operation of Gliders and Soaring Planes. New York: Ronald Press Company. Walter, W. (1938). How To Improve Your Glider Flights. Model Airplane News , np. Read More