A glider is defined as heavier than air aircraft supported in the air by dynamic air reactions against its lifting surfaces. Normally, its free flight does not depend on an engine. Most of the gliders do not have engine, though the motor gliders have engines meant for extending their flight when requires and some are powerful allowing them to take off. Because of their specialized use, gliders are quite different from powered airplanes. This is made obvious by several characteristics. One is the completely different arrangement of the landing gear, a result of the lightweight of the aircraft and the absence of a propeller. Others are that the pilot’s seat is located toward the front for center-of-gravity reasons, the wing span is always considerable, and the fuselage and other components are well streamlined to obtain the maximum aerodynamic efficiency balsa wood gliders also known as Styrofoam, are inexpensive vehicles for learning individuals or students to have fun while learning aerodynamics (Mangio, 2010, p. 218).
Goal of Gliders
The various purposes of gliders differ greatly. Some are designed to mainly to descend. The most common include the sailplanes, these gliders exploit the meteorological phenomena to maintain or gain height. Gliders are mainly used in sports known as air sports of gliding, paragliding and hand gliding. They are also used for spacecraft recovery and even in warfare in the past. The most common purpose of gliders is toys such as balsa wood glider and the paper plane.
Requirements of Gliders
There are various requirements that one must have in order to fly as written by (George, 1992), the candidate should be in a position to exhibit the necessary level of capability for the original issue of the Cloud flying support. Proficiency can be demonstrated by either candidates holding PPL or higher licenses and, within the previous 5 years, an Instrument meteorological conditions rating or instrument rating qualify for the automatic issue of a Cloud flying endorsement valid for a period of 5 years. A satisfactory proficiency check is required, covering a reasonable perceptive of the rules that of the air, presentation considerations of the major flight instruments pertinent to apparatus flying, factors in human performance, performance of the aircraft, and the ability to demonstrate the following during flight;
- Satisfactory levels of control during cloud entry, maneuvering whilst in cloud, and exit from cloud
- Satisfactory levels of situational awareness and navigation.
Restrictions of Gliders
According to researchers, one is considered as part of a flight crew hence aviation rules and regulation apply. One must drink alcohol before gliding or suffer from previous evening. Moreover, donation of blood, minor illnesses and drugs may make the glider unfit to fly and one should seek medical advice. Persons under the eighteen years of age must inform their parents about the project. The weather can also affect a flight by postponing until when recommended for flight. The weather conditions include low cloud, rain, poor visibility and strong wind. The following are conditions that restrict a glider. These include:
- Blackouts from any cause
- Ear disease
- Defective vision
- Severe head injury
- Recurrent fainting or giddiness
- Diabetes of any form
- High blood pressure
- Kidney stones
- Psychiatric disorders
Stability and Range of Gliders
An airplane has longitudinal, lateral, or directional stability if it returns to its original attitude when disturbed by external forces from its straight-and-level flight by newly generated involuntary forces without the intervention of the pilot. Static stability is experienced when spontaneous forces acting on the airplane will re-establish the conditions that were originally upset by outside forces. While returning to its original setting, it is possible that the point of equilibrium is passed, thus beginning a number of oscillations. These oscillations may decrease or increase in amplitude. If the oscillations decrease at a fast rate, it means that the plane possesses not only static stability but also dynamic stability. An airplane requires static stability and dynamic stability to reduce any oscillations. The components for stability and maneuvering are the entire tail section and the ailerons. The tail section is usually characterized by a fixed portion and by a movable one used for maneuvering, in other words, for changing the plane’s attitude or correcting accidental variations. The ailerons are used for lateral maneuvering or to re-establish lateral stability.
Balsa Glider Construction Below is a basic set of instructions for the building of common balsa wood gliders. As illustrated by (De, 2003), the construction begins with selecting the type of wood for the wing, tail, fin and the fuselage. For the wing, select a medium grain sheet made of balsa wood 1/4" (6mm) sheet. Look for nice 'clean' wood. Look along the edge of the sheet or at the length of the wood to see if it is straight. Preferred is quarter grain, quarter cut wood recommended for the wings, fin and tail. Stiffness of the quarter grain wood is a major benefit of using the material. Use medium weight type for the tail and fin if you can obtain it otherwise insist on medium straight grain. While constructing the fuselage, try to use a hard grade type of wood to build the fuselage.
Before building any model, copy the plan and use the image to offer guidance when building. Slowly, cut out the main images from the copy of the plan and use these image shapes as templates as marked parts of the wood. Cut out the wing shape from the balsa wood, using a razor blade, thin the wing from the center to the tip. Mark the highest point onto the wing. Position a piece of plastic on the wing joint. Get rid of the plastic strips once the glue dries (Krishanderan, 2007, p. 11).
When building the balsa fuselage, create a thin rear end to minimize weight. Use glue to build, laminate the fuselage parts and to fix the pivot side plates. Put fiberglass reinforcing after glue dries. Cut out the parts neatly, then feather the edges down. Apply glue on the fin and tail. Cyano is preferred for wood-to-wood joints. Apply a coat of two-part fuel to waterproof the model. Tail feathers and wing tips should be lightly strayed with fluorescent orange paint. A proficiency check is required. In addition, covering an adequate understanding of the appropriate rules of the air is necessary. Therefore, before building any model, copy the plan and use the image to offer guidance when building. Slowly, cut out the main images from the copy of the plan, and use these image shapes of templates as marked parts of the wood. Notably, Most of the gliders do not have engine, though the motor gliders have engines meant for extending their flight when requires and some are powerful allowing them to take off.
Mangio, A. L. (2010). Flying Wing Optimization.
Krishanderan, K., & Vasudhevan, K. (2007). Design of model glider (Doctoral dissertation, University Malaysia Pahang).
De Weck, O. L., Young, P. W., & Adams, D. (2003). The Three Principles of Powered Flight: An Active Learning Approach. In 2003 ASEE Annual Conference & Exposition: Staying in Tune with Engineering Education.
George, L. (2007, April). Engineering 100: An Introduction to Engineering Systems at the US Air Force Academy. In System of Systems Engineering, 2007. SoSE'07. IEEE International Conference on (pp. 1-6). IEEE.