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Monday, April 19, 2010

Designing an aircraft


Radio controlled model aircraft can be designed using some basic rules of thumb or more appropriately, design paramaters. These basic design parameters can be applied to a trainer or sport model. There are no complex or magic formulas to solve. These paramaters have been proven to work by a multitude of sport models that have been developed using these rules. A modeler who has built a few models and has gained some knowledge of common structures can design a plane that suits his individual needs.
Parameters Diagram


The design begins with selecting the size of engine that will be used. This will become the determining factor for the entire design. The wing area is first selected from the table.
Engine/Wing Area  
ENGINEWING AREA
.049200 - 250 sq. in.
.10250 - 350 sq. in.
.15300 - 450 sq. in.
.25400 - 500 sq. in.
.40500 - 700 sq. in.
.60600 - 850 sq. in.



After selecting the engine size and wing area, the next step is to determine the wingspan and wing chord that will give this wing area and an aspect ratio between 5:1 and 6:1. If .40 size engine is selected, the wing area will be 500 - 700 sq. in. To make things simple, and area of 600 sq. in. and a span of 60" is chosen. This will give a chord of 10" and an aspect ratio of 6:1. The rest of the design will be based on the chord length.
The next step in determining the configuration of the wing is selecting the airfoil according to the purpose of the model.
Airfoil Type  
AIRFOIL SHAPECHARACTERISTIC
Flat BottomSlow, docile, forgiving, poor inverted flight
Semi-symmetricalGood lift, penetration, aerobatic, and inverted flight
SymmetricalBest aerobatic and inverted flight



Programs can be downloaded that will draw one of a multitude of airfoils. Airfoils can also be plotted manually using the coordinate dimensions to draw points on the airfoil and drawing the curve of the airfoil using a French curve or flexible rule. The airfoil that is selected should have a thickness of 15% - 18% of the chord at 30% - 40% from the leading edge and should have a blunt leading edge for gentle stall characteristics. The wing incidence is normally set to 0°. The dihedral will be 0° - 3° with ailerons and 3° - 5° without ailerons. Finally, the type of ailerons that will be used is selected and the size determined according to the chord.
The fuselage length is now calculated using the 10" chord. The nose will be 10" - 15" and the tail will be 20" - 24". Taking the median dimension of these, the fuselage length will be 44 1/2" (12.5" nose + 10" chord + 22" tail). The engine thrust is usually set for 0° - 3° down and 0° - 3° to the right. The landing gear is selected as a matter of preference. A conventional landing gear is set even with the leading edge of the wing. The main gear of a tricycle landing gear is placed 1 1/2" behind the center of gravity. The width of either main gear is 1/4 of the wingspan.
The stabilizer area will be 20% - 22% of the wing area. The area for the 600 sq. in. wing would be 126 sq. in. nominal. The aspect ratio for the stabilizer is 3:1. Using a stabilizer chord of 6 1/2", the length of the stabiler would be 19 1/2" and the area would be 127 sq. in. The elevator is 20%; of the stabilizer area or 25 sq. in.
The fin is 1/3 of the stabilizer area and the rudder is 1/3 - 1/2 of the total fin area. For the current example, the total area of the fin would be 42 sq. in. and the rudder would be 21 sq. in.
The type of structure that is designed will depend on the use for which the model is intended and the personal preference of the builder. The slab sided fuselages are easier to build than the truss work structures but are also heavier and stronger in most cases. Foam wings are easier to build than built up wings but are heavier and more accurate. A little knowledge of structure goes a long way in the design of a model. In many cases, a modeler will design using the structural configuration of another model and simply change the appearance or the size of the model.


Flying Basics


You Can Fly an R/C Airplane!
For most people, the beauty of an airplane's design lies in its lines and curves. For the flier, however, the beauty of a design includes what that design can do. That feeling is as true for R/C (radio control) pilots as it is for pilots of full-size aircraft. Their differences—aircraft size, and the fact that R/C pilots remain on the ground—have very little impact on the way given designs perform. As a result, R/C hobbyists have been able to model and fly aircraft that range from the Wright Brothers' first plane to the magnificent Space Shuttle.
Aerodynamics:
To fly, an airplane's wing has to overcome gravity by developing lift greater than the weight of the plane. Since it can't do that standing still, airplanes use thrust...force directed backwards...to drive the wing forward through the air and generate lift. However, thrust has its own opposition to overcome in the form of drag—the resistance of the air to a body moving through it. If lift and thrust are greater than gravity and drag, you have the potential for flight...and fun Wing placement, for the most part, falls into two major categories—high wing design and low wing design. In a high wing design, the weight of the model is suspended below the wing. When the model tilts, the model's weight tries to return it to a level position. As a result, high-wing models tend to be more stable, easier to fly—and natural choices for trainers. A low-wing model is just the opposite. With its weight above the wing, it tends to be less stable—excellent for advanced fliers who want to perform rolls, loops and other aerobatic maneuvers Airfoil: If you face the wing tip of the plane and cut it from front to back, the cross section exposed would be the wing's airfoil. The Flat-Bottom Airfoil will develop the most lift at low speeds and helps return the model to upright when tilted. This is ideal for trainers and first-time pilots. A Symmetrical Airfoil's top and bottom have the same shape, allowing it to produce lift equally whether right side up or upside down and to transition between the two smoothly. This is recommended for advanced pilots. Lastly, a Semi-Symmetrical Airfoil is a combination of the other two and favored by intermediate and sport pilots. Wing Area/Wing Loading: Wing area is the amount of wing surface available to create lift. Wing loading is the weight that a given area of the wing has to lift and is usually measured in ounces per square foot. Generally, a light wing loading is best for beginners. The plane will perform better and be easier to control. Dihedral: Dihedral is the upward angle of the wings from the fuselage.Dihedral increases stability and decreases aerobatic ability.

Wing Thickness:
Wing thickness — measured from top to bottom — determines how much drag is created. A thick wing creates more drag, causing slower speeds and gentler stalls and is ideal for beginners. A thin wing permits higher speeds and sudden stalls — desirable for racing and certain aerobatic maneuvers.
Landing Gear Location:
Tricycle gear includes a nose gear and two wing (main) gears, making takeoffs and landings easier—ideal for beginners.
Choosing the Size of Your Plane
The "size" of a model plane generally refers to the size of engine, in cubic inch displacement, required to fly it successfully. The most popular sizes are 20 (requiring a .20-.36 engine), 40 (.40-.53 engine) and 60 (.60-.75 engine). Many other sizes are available, too, ranging from small, .049-powered craft up to massive, giant-scale models.
Most trainers fall into the 40-size category. That's because 40s are fairly stable, with enough heft to fly well in breezy conditions, but still small enough to be affordable for new hobbyists. Many 60-size trainers are also available, and offer the advantage of even greater stability—plus easier visibility once aloft—both due to their larger dimension.
 
Choosing Your Type of Plane
 
What first attracts many would-be pilots to the idea of R/C flying is the thought of controlling a blistering-fast ducted fan jet or wicked WWII war bird. And there's no better way to put a quick END to your flying career than to start with such a model They're simply not designed for anyone who hasn't yet developed sharp piloting skills. Model plane styles are available that duplicate virtually every kind of full-size aircraft. The best ones for the first-timers are, without question, trainers and trainer-like sailplanes. These are specifically engineered to fly slowly and smoothly. They'll keep you out of trouble—giving you time to acquire the skill and confidence You'll need for those jets and warbirds.

Engines

Model planes can use several different types of power sources. Electric models carry battery-powered motors to turn the propeller. Gliders or sailplanes ride on thermal air currents (some also have electric motors for quick launching to great heights). Most R/C models, however, are powered by glow engines.
The most economical are basic 2-stroke engines with brass bushings supporting the crankshaft. For a little more power, you might choose a 2-stroke that uses ball bearings to support the crankshaft. The ball bearings also extend the life of the engine, so you can continue using it to power future models. The cost, however, is nearly twice that of a bushing-equipped engine.
Finally, there's the 4-stroke glow engine—slightly less powerful than 2-strokes of the same size and higher priced, but offering more torque, swinging bigger props, using less fuel and sounding much more realistic.

Accessories

When you buy a model airplane, you'll probably also need to buy a number of additional, inexpensive accessory items to make it flight-ready (those items are listed under the Accessories Required links for the plane you choose). These parts are traditionally left out of kits because the appropriate sizes depend on your choice of engine; also, experienced hobbyists may have a brand preference or already keep those parts in their workshop. Required accessories often include the following:
Covering
The adhesive-backed, plastic or fabric "skin" that surrounds a model airplane's structure, applied by a process of heating and stretching.
Pushrods
Rods that link your radio system's servos to the parts of the model that those servos move. They're often made of wire or a firm piece of balsa, fiberglass, or plastic, with a clevis fastener at the end.
Control Horn
A bracket, mounted on a part of the model, where the pushrods are attached.
Hinges
Connect the moveable surfaces of a model to the main, static structure.
Foam Rubber
Used to cushion the on-board radio equipment to protect it from engine vibration.
Wing Seating Tape
Applied where the wing fits onto the fuselage, to cushion the wing and prevent exhaust oils from entering the fuselage.
Wheel Collars
Small metal collars, which keep the plane’s wheels, positioned correctly on the axle.
Wheels
Available in several styles, such as treaded, non-treaded, scale, and air-filled.
Spinner
Plastic or aluminum cone mounted at the "nose" of the plane to improve looks and aerodynamics.
Engine Mount
Reinforced structure, often made of nylon or aluminum, that allows your engine to be attached securely to the plane.
Fuel Tank, Tubing & Filters
The sized used depends on the engine you select; therefore, these often are not included with the model.
Engine Accessories
Propellers are usually not included with the engine or the plane; also, your engine may or may not come with a muffler and glow plug.
Field Equipment
Once y0ur aircraft is chosen, built and covered, there's only one thing left to do...fly it! To do that, you'll need what we refer to as "flight line equipment"—such as fuel, a fuel pump, engine starting equipment and a few other basic tools. Except for the fuel, most flight line supplies are one-time purchases. You can use them throughout your modeling career, with as many different models as you fly.
Most modelers go to the field equipped with the following, all stored in a "flight box" for easy transport:
Power Panel
The centralized power source for electrical field equipment
12V Field Battery
To supply power to the power panel
DC Charger
To recharge the 12V field battery

Glow Plug Clip
An electric device that gives your engine's glow plug the initial heat it needs to burn fuel
Fuel Pump
To move fuel from your gallon can or jug to the plane's fuel tank, available in hand-crank or electric-powered styles
Fuel Line, Filters & Cap Fittings
To connect your fuel to the pump, and the pump to the plane's fuel tank.

12V Electric Starter
A device for quick, easy engine starting, powered from the power panel (a small wooden dowel or "chicken stick" can also be used).
Miscellaneous Tools
Including a 4-way glow plug/prop wrench.
Glow plugs and propellers
It's always a good idea to carry extras...without a spare, you might be forced to stop flying early.
The glow fuel used for a model engines carries a percent rating, which indicates its nitro methane content. For trainer aircraft, 10% or 15% is recommended. Use a good quality fuel with a blend of castor oil and synthetic lubricants to protect your engine. Avoid "cheap" fuels, which sometimes attract moisture and cause engine parts to rust.

Saturday, April 17, 2010

Our Mission



Our Mission

Knowledge, hard work, commitment, honesty and understanding are some of many keys used for opening the Sphere of success. Being an aviation products related company, we provide quality equipments to make aero sport safer and reliable. Our mission is to encourage aero sport and make the Aeromodelling equipment availability easier, faster and at economical price. There are several enthusiast who need correct link, equipment, support and guidance to fulfill their fantasy of flying, we are behind them to support at every step and offer them all the required material, technology, knowledge, equipments, training, services and products. We are running On-Line Shopping for the same so that people from any part of country could order and purchase aeromodels to enjoy this hobby of Flying.

Our Vision

In technological era where every thing is as fast as a jet plane and as scattered as internet web, we are providing hi-tech flying toys, aeromodels, training, consultancy and services through our On-Line Hobby Shop where customers can get detailed knowledge look and feel of the product before purchasing. We hope more and more people around India will get to know and enjoy this hobby of flying by getting Aeromodelling products faster, easier and at pocket friendly prices at any part of this world. As Aeromodelling is picking up in India, anybody could have fun with miniature airplane which will really fly with controls in their hands. we are putting all our efforts by displaying products on net, informative emails, graphical presentation, web learning and training modules, flying video on demand, assistance, help, guidance and faster correspondence through our portal to make our vision a reality where every body can enjoy flying.


Company Profile

aeromodelling Hobbies is a team of aviation enthusiast developing aero sport related products since last 10 years, owned by Captain Nilesh Doshi (CPL from USA ). We are operating an Aerosports Club and perform Air-Shows & Aerosporting events. We are imparting aviation knowledge in schooling education and provide career consultancy in Aviation and related fields. We manufacture Aeromodelling products and supply them at economical rates to hobby flyers, Pilot training academy, flying schools, and several aeronautical, engineering and educational institutions. We are biggest importer of Aeromodelling equipments in India and major suppliers of Futaba Transmitters, Receivers, Radio sets, Servos, Fuel pumps, Glow Plugs, Flying Toys, O.S engines, RTF Model Aircrafts and kits. We have are selling our products through internet since last 5 years and operating e-commerce, web education, On-Line Shopping to ease and comfort our customers.