| Kent County Aero Modelers Hints & TipsKent County Aero Modelers Hints & Tips |
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Radio controlled aircraft modeling is one of the most exciting hobbies available. It involves many interests, disciplines, and skills. Some of these are aerodynamics, electronics, mechanics, drafting and design, composite material construction, and woodworking, and these are in the airplane alone. There are many other fields of interest in the hobby of aircraft modeling; far too many and too varied to try to list. Many people find that many new skills must be learned before they are ready to begin to learn to fly. The hobby is constantly changing as new technology is developed. A new modeler may become frustrated at times but certainly not bored. A beginner should understand the basic concepts of flight. The theories behind the physics of flight are covered in many volumes of books. There are different and sometimes conflicting theories and arguments as to how airplanes fly, but the one accepted principle is that lift is generated as a result of the air pressure on the bottom of the wing being higher than the air pressure on the top of the wing.
The Lift Diagram shows some of the basic terms relating to a wing section. These terms are common to R/C flight. Airfoil - The cross section of the wing Angle of Attack - The angle between the chord line and the relative direction of flight Chord Line - The line between the leading edge and the trailing edge of the airfoil Direction of Flight - The relative direction of the wing in relation to still air Leading Edge - The most forward edge of the wing Trailing Edge - The most rearward edge of the wing There are four (4) primary forces that act on an aircraft in flight; thrust, lift, drag, and weight. Thrust is the force applied by the combination of engine and propeller acting to pull the aircraft forward. Drag is the resistance against the aircraft by the force of the air against the forward facing surfaces. Weight is caused by gravity. In order for a constant speed to be maintained, thrust and drag must be equal. In order for a constant altitude to be maintained, lift and weight must be equal.
Lift increases as the velocity of the air passing over the wing increases or as the angle of attack increases as long as the flow of air over the wing remains smooth. Actual flight is attained when the force of the lift equals weight. An aircraft pivots about three (3) axes; the yaw or vertical axis controlled by the rudder, the pitch or lateral axis controlled by the elevator, and the roll or longitudinal axis controlled by the ailerons. It can pivot about any one of these individually or in combination based on the control surfaces that are moved and the direction of the movement.
Quite often a person has an interest in model airplanes and visits a local flying field just to observe. He sees all types of airplanes from trainers to pattern planes to scale World War II fighter planes. His interest is piqued by all the fabulous looking models. He thinks, "I have to have one of those Mustangs." He immediately sets out trying to find a P-51 model to begin his modeling hobby. This is a serious mistake. Many hours of training and practice are involved before a beginner has the ability to handle the more advanced models. A beginner must realize the dedication that is required to gain the ability to fly the type of model that initially spawned his interest. He must begin the hobby with a basic trainer and progress through different levels of models until his goal is reached. A trainer is a specific type of model aircraft that is designed to be stable in flight. This means that it has an inherent ability to correct itself and overcome the rotational forces applied so that it regains straight and level flight. Most trainers are designed to that they remain stable in slow flight so that they are easy to land.
The Basic Trainer diagram shows the components of a common trainer. Aileron - The moveable portion of the wing which causes a change about the roll axisCowling - The part of the fuselage which covers the engine Engine - A 2 - cycle reciprocating machine which provides the motivational power Elevator - The moveable portion of the horizontal stabilizer which causes a change about the pitch axis Fin - Properly known as vertical stabilizer which provides stabilization about the yaw axis Fuselage - The main body of an aircraft that holds the components and cargo Landing Gear - The supporting structure of an aircraft including landing gear struts and wheels Propeller (Prop) - The combination of blades which provide thrust Rudder - The moveable portion of the vertical stabilizer which causes change about the yaw axis Spinner - Covering over the propeller hub Stabilizer - Properly known as horizontal stabilizer which provides stabilization about the pitch axis Wing - The horizontal surfaces which provide the lifting forces There are certain criteria that a trainer should have in order to be satisfactory for a beginner. A trainer that meets these guidelines will give the beginner excellent service without the frustration that can occur with an inappropriate model. With proper instruction, the beginner can progress quickly to his solo flight and on to the novice stage and still get years of sport flying from the trainer. There are several trainers on the market that meet and far exceed the guidelines. These range from the most basic kit to beautiful Almost Ready to Fly (ARF) models and Virtually Ready to Fly (VRTF) complete with engine and radio. There are a lot of considerations when choosing a trainer but the two most basic are time and money. A trainer built from a kit has the advantage of being less expensive in some cases. It gives the builder the pleasure of building, the option of color and trim scheme, and the knowledge of the structure to perform repairs. The biggest disadvantage is the time required to construct the model when the beginner would rather be learning to fly. Another disadvantage in some cases is the emotional attachment the builder develops having spent many hours on his creation. The big advantage of the ARF models is that they can be assembled in a matter of a few hours and the beginner can be ready to start his flying lessons. The disadvantages are the cost, the unknown structure that is sometimes weak, and the fixed color scheme. Most ARF models perform as well or almost as well as any kit built model on the market. Any beginner who purchases an ARF model should get an experienced modeler to check the model before assembly is started. An experienced modeler can point out areas that may need to be reglued or reinforced. There are several models that are widely accepted as being the best in the field although there is disagreement as to which is the "All Time Best". The list is not an all-inclusive but includes those that are most widely accepted and therefore are most widely recommended by novices and seasoned veterans of the hobby. Some of the trainers are also available in .20 and .60 size but the .40 is the most widely accepted.
Most if not all of the models listed have been reviewed by one of the major model magazines. A beginner can get information from these reviews that may help in deciding which model to buy and the areas of assembly that need special attention. Regardless of the amount of advice that the beginner gets from experienced modelers, the final decision is the beginner's. The choice of a model is an individual choice and all the pros and cons must be weighed. Each person must decide which model is pleasing in appearance and performance and which one will meet his needs. The final consideration should be that the model should be considered disposable. Many trainers are destined for the junk pile when it has served its purpose. |
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