Flying model aircraft


Flying models are usually what is meant by the term aeromodelling. Most flying model aircraft can be placed in one of three groups:

Free flight (F/F) model aircraft fly without any attachment to the ground.
This type of model pre-dates the efforts of the Wright Brothers [1] and other pioneers.

Control line (C/L) model aircraft use cables (usually two) leading from the wing to the pilot. A variation of this system is the Round-the-pole flying (RTP) model.

Radio-controlled aircraft have a transmitter operated by the pilot on the ground, sending signals to a receiver in the craft.

Some flying models resemble scaled down versions of piloted aircraft, while others are built with no intention of looking like piloted aircraft. There are also models of birds and flying dinosaurs. One company, Flying ThingZ of Stroudsburg, Pennsylvania, makes unusual offerings, produced from laser-cut corrugated plastic include a witch on a broomstick, a flying M1A2 Abrams tank, a flying race car and even a 2/3-scale flying lawnmower.

 

Construction

The construction of flying models is very different from most static models. Flying models borrow construction techniques from (usually vintage) full-sized aircraft (although models rarely use metal structures.) These might consist of forming the frame of the model using thin strips of light wood such as balsa, then covering it with fabric and subsequently doping the fabric to form a light and sturdy frame which is also airtight. For very light models, very thin paper can be substituted for fabric. Heat-curing plastic films ("heat shrink covering" or "solarfilm") can be ironed on — a hand-held iron causes the film to shrink and adhere to the frame. A hair dryer can also be used.

Other model construction techniques consist of using formers and longerons for the fuselage, and spars and ribs for the wings and tail surfaces. More robust designs may use solid sheets of wood to form these instead, or might employ a composite wing consisting of an expanded polystyrene core laminated with a surface veneer of wood, often obechi, which protects the core and provides strength. Such designs tend to be heavier than an equivalent sized model built using the traditional method, and would be much more likely to be found in a power model than a glider.

The lightest models are suitable for indoor flight, in a windless environment. Some of these are made by bringing frames of balsa wood and carbon fiber up through water to pick up thin plastic films, similar to rainbow colored oil films. The advent of "foamies," or craft injection-molded from lightweight foam and sometimes reinforced with carbon fiber, have made indoor flight more accessible to hobbyists. Many come ready-to-fly, requiring little more than attachment of the wing and landing gear.

Flying models can be built from scratch using published plans, or assembled from kits. Plans are intended for the more experienced modeller, since all parts must be sourced separately. The kit contains most of the raw material for an unassembled plane, a set of assembly instructions, and a few spare parts to allow for builder error. Assembling a model from plans or a kit can be very labour-intensive. In order to complete the construction of a model, the builder assembles the frame, covers it, and aligns the control surfaces.

To increase the hobby's accessibility to the inexperienced, vendors of model aircraft have introduced Almost Ready to Fly (ARF) designs. Compared to a traditional kit design, an ARF design reduces the amount of time, skill, and tooling required for assembly. The average ARF aircraft can be built with less than 4 hours of labor, versus 10-20+ for a traditional kit aircraft. More recently, Ready To Fly (RTF) radio control aircraft have all but eliminated assembly time (at the expense of the model's configuration options.) Among traditional hobbyist builders, RTF models are a point of controversy, as many consider model assembly as integral to the hobby. Brands associated with these types of aircraft include Great Planes, Hobbico, Carl Goldberg Products, Lanier RC, E-Flite, Hangar 9, GWS, HobbyZone and ParkZone Tower Hobbies.

 

Gliders

Gliders are aircraft with no attached powerplant. Model gliders are usually hand-launched or catapult-launched (using an elastic bungee.) The newer "discus" style of wingtip handlaunching has largely supplanted the earlier "javelin" type of launch. Other launch methods include ground based power winches, hand-towing, and towing aloft using a second powered aircraft. As gliders are unpowered, flight must be sustained through exploitation of the natural wind in the environment. A hill or slope will often produce updrafts of air which will sustain the flight of a glider. This is called slope soaring, and when piloted skillfully, radio controlled gliders can remain airborne for as long as the updraft remains. Another means of attaining height in a glider is exploitation of thermals, which are bubbles or columns of warm rising air created by hot spots on the ground. As with a powered aircraft, lift is obtained by the action of the wings as the aircraft moves through the air, but in a glider, height can only be gained by flying through air that is rising faster than the aircraft is sinking relative to the airflow.

Sailplanes are flown using available thermal lift. As thermals can only be indirectly observed through the reaction of the aircraft to the invisible rising air currents, pilots find sailplane flying challenging and rewarding.

Hang gliders come in two large categories: hang glider and paraglider. The default use of the term is for the stiffened-wing sort; the paraglider is fully flexible winged.

Walkalong gliders are light weight model airplanes flown in the ridge lift produced by the pilot following in close proximity. In other words, the glider is slope soaring in the updraft of the moving pilot.

From Wikipedia, the free encyclopedia.
All text is available under the terms of the GNU Free Documentation License.