model aircraft

 

  • [6] V-1 flying bomb type Pulsejet engines have also been used as they offer more thrust in a smaller package than a traditional glow-engine, but are not widely used due to
    the extremely high noise levels they produce, and are illegal in some countries.

  • Flyers can now also use single-use model rocket engines to provide a short, under 10 second burst of power.

  • Flying models borrow construction techniques from full-sized aircraft although the use of metal is limited.

  • Flying models[edit] A free-flight hand-launched glider Generally known collectively as aeromodelling, some flying models resemble scaled down versions of full scale aircraft,
    while others are built with no intention of looking like real aircraft.

  • Static display models Static model aircraft cannot fly, and are used for display, education and are used in wind tunnels to collect data for the design of full scale aircraft.

  • Control[edit] Flying model aircraft are generally controlled through one of three methods • Free flight (F/F) model aircraft are uncontrolled other than by control surfaces
    that must be preset before flight, and must have a high degree of natural stability.

  • Compressed CO2 may also be used to power an expansion engine to turn a propeller.

  • Ducted fans are popular with scale models of jet aircraft, where they mimic the appearance of jet engines but they are also found on non-scale and sport models, and even lightweight
    3D-flyers.

  • For a more mass market approach, foamies, injection-molded from lightweight foam (sometimes reinforced) have made indoor flight more accessible and many require little more
    than attaching the wing and landing gear.

  • Desktop model airplanes may be given to airport, airline and government officials to promote an airline or celebrate a new route or an achievement..[1] Scale Static model
    aircraft are primarily available commercially in a variety of scales from as large as 1:18 scale to as small as 1:1250 scale.

  • Power sources[edit] Typical rubber powered model having the rubber band (hidden in the fuselage) tightened by turning the propeller backwards, here being done with a handcrank
    Powered models contain an onboard powerplant, a mechanism powering propulsion of the aircraft through the air.

  • Some can be very large, especially when used to research the flight properties of a proposed full scale aircraft.

  • Aerodynamic research and mock-ups Models are made for wind tunnel and free-flight research tests and may have components that can be swapped to compare various fittings and
    configurations, or have features such as controls that can be repositioned to reflect various in flight configurations.

  • [3] • Control line (C/L) model aircraft use strings or wires to tether the model to a central pivot, either held by hand or to a pole.

  • The reduced size affects the model’s Reynolds number which determines how the air reacts when flowing past the model, and compared to a full sized aircraft the size of control
    surfaces needed, the stability and the effectiveness of specific airfoil sections may differ considerably requiring changes to the design.

  • They may be built using any suitable material, which often includes plastic, wood, metal, paper and fiberglass and may be built to a specific scale, so that the size of the
    original may be compared to that of other aircraft.

  • They are available for both electric and liquid-fuelled engines, although they have only become common with recent improvements in electric-flight technology.

  • Very rarely, some electric motors are designed with a sufficiently high torque and low enough speed and can utilize direct-drive as well.

  • Flying models construction may differ from that of static models as both weight and strength are major considerations.

  • Electric power now predominated with park-flyer and 3D-flyer models, both of which are small and light, where electric-power offers greater efficiency and reliability, less
    maintenance and mess, quieter flight and near-instantaneous throttle response compared to gas engines.

  • Rubber[edit] The oldest method of powering free flight models is Alphonse Pénaud’s elastic motor (or extensible motor) of 1871, essentially a long rubber band that is twisted
    to add tension, prior to flight.

  • Internal combustion[edit] “Giant scale” 18 feet 6 inches (5.64 m) wingspan Lockheed C-130 Hercules radio control flying model powered with four internal combustion engines.

  • Larger outdoor model gliders are usually radio-controlled gliders and hand-winched against the wind by a line attached to a hook under the fuselage with a ring, so that the
    line will drop when the model is overhead.

  • Traditionally, the radio signal directly controlled servos, however, modern examples often use flight control computers to stabilize the model or even to fly it autonomously.

  • 1:72 was popularized in the US during the Second World War by the US War Department after it requested models of commonly encountered single engine aircraft at that scale,
    and multi-engine aircraft in 1:144th scale.

  • From World War I through the 1950s, static model airplanes were also built from light weight bamboo or balsa wood and covered with tissue paper in the same manner as with
    flying models.

  • A model aircraft can now be fitted with four electric ducted fans for less than the cost of a single jet turbine, enabling affordable modelling of multi-engine aeroplanes.

  • Also using ground-based power winches, hand-towing, and towing aloft using a second powered aircraft.

  • Full-scale static engineering models are also constructed for production development, often made of different materials from the proposed design.

  • Electrical power began being used on models in the 1970s, but the cost delayed widespread use until the early 1990s, when more efficient battery technologies, and brushless
    motors became available, while the costs of motors, batteries and control systems dropped dramatically.

  • The pitch is the distance that the propeller would advance if turned through one revolution in a solid medium.

  • The first electric models used brushed DC motors and nickel cadmium (NiCad) rechargeable cells which gave flight times of 5 to 10 minutes, while a comparable glow-engine provided
    double the flight-time.

  • Rocket engines are sometimes used to boost gliders and sailplanes and the earliest purpose-built rocket motor dates back to the 1950s.

  • Ready To Fly (RTF) radio control aircraft are also available, however model building remains integral to the hobby for many.

  • Small jet turbine engines are now used in hobbyist models that resemble simplified versions of the turbojet engines found on commercial aircraft, but are not scaled-down as
    Renold’s numbers come into play.

  • Aircraft manufacturers and researchers make wind tunnel models for testing aerodynamic properties, for basic research, or for the development of new designs.

  • These engines are inexpensive, and offer the highest power-to-weight ratio of all glow-engines, but are noisy and require substantial expansion chamber mufflers, which may
    be tuned.

  • Many model makers would create models from drawings of the actual aircraft.

  • For wind tunnel research, it is sometimes only necessary to make part of the proposed aircraft.

  • Resin kits are made in forms similar to those used for limited run plastic kits, but these moulds are usually not as durable, which limits them to smaller production runs,
    and prices for the finished product are higher.

  • A kit contains the necessary raw material, typically die- or laser-cut wood parts, some moulded parts, plans, assembly instructions and may have been flight tested.

  • Steam is even older than rubber power, and like rubber, contributed much to aviation history, is now rarely used.

  • Propellers generate thrust due to lift generated by the wing-like sections of the blades, which forces air backwards.

  • The aircraft then flies in circles around that point, secured by one cable, while a second provides pitch control through a connection to the elevator.

  • four-stroke cycle glow engines, whether using poppet valves or more rarely rotary valves are more fuel-efficient, but deliver less power than similar two-stroke engines.

  • Three methods are used to transfer energy to the propeller: • Direct-drive systems have the propeller attached directly to the engine’s crankshaft or driveshaft.

  • Airlines used to order large scale models of their aircraft to supply them to travel agencies as a promotional item.

  • Non-flying models are also termed static, display, or shelf models.

  • Using it efficiently is one of the challenges of competitive free-flight rubber flying, and variable-pitch propellers, differential wing and tailplane incidence and rudder
    settings, controlled by timers, can help to manage the torque.

  • Speed flying is divided into classes based on engine displacement.

  • Government restrictions in some countries made rocket-propulsion rare but these were being eased in many places and their use was expanding, however a reclassification from
    “smoke producing devices” to “fireworks” has made them difficult to obtain again.

  • Some manufacturers made 1:18th scale aircraft to go with cars of the same scale.

  • It is now possible to power most models under 20 lb (9.1 kg) with electric power for a cost equivalent to or lower than traditional power sources.

  • Walkalong gliders are lightweight model airplanes flown in the ridge lift produced by the pilot following in close proximity.

  • Owning or operating a turbine-powered aircraft is prohibitively expensive and many national aeromodelling clubs (as with the USA’s Academy of Model Aeronautics) require members
    to be certified to safely use them.

  • Construction[edit] Extremely light F1D-class indoor-flight model with microfilm covering Flying model of a WW1 Royal Aircraft Factory S.E.5a with foam flying surfaces, from
    a kit.

  • Older models often did not conform to an established scale as they were sized to fit the box, and are referred to as being to “Box Scale”.

  • Static models range from mass-produced toys in white metal or plastic to highly accurate and detailed models produced for museum display and requiring thousands of hours of
    work.

  • To increase line tension, models may be built or adjusted in various ways.

  • F2D – CL Combat[edit] CLASS F2D – Control Line Combat Model Aircraft – Two pilots compete, with four mechanics in the pit.

  • These engines can incorporate speed controls and multiple cylinders, and are capable of powering lightweight scale radio-controlled aircraft.

  • Model aircraft are divided into two basic groups: flying and non-flying.

  • To increase the hobby’s accessibility, some vendors offer Almost Ready to Fly (ARF) models which minimize the skills required, and reduce build time to under 4 hours, versus
    10–40 or more for a traditional kit.

  • Normally the model is flown in a circle and controlled by a pilot in the center holding a handle connected to two thin steel wires.

  • Home manufacture of model aircraft engines is a hobby in its own right.

  • [2] Ready-made desk-top models include those produced in fiberglass for travel agents and aircraft manufacturers, as well as collectors models made from die-cast metal, mahogany,
    resin and plastic.

  • There are contest categories for control line models, including Speed, Aerobatics (AKA Stunt), Racing, Navy Carrier, Balloon Bust, Scale, and Combat.

  • The design of brushless motors also means less internal friction, as there is no requirement for brushes to be in contact with any rotating parts.

  • Much like quadcopters, this has now extended to all flight controls.

  • For larger models (usually powered and radio controlled) heat-curing or heat shrink covering plastic films or heat-shrinkable synthetic fabrics are applied to the model.

  • The first hobbyist-developed turbine was developed and flown in the 1980s but only recently have commercial examples become readily available.

 

Works Cited

[‘0. Scott Mayerowitz, AP Airlines Writer (18 March 2015). “Airline world’s tiny secret: infatuation with model planes”. USA TODAY.
1. ^ “Building a 1948 Model Airplane Kit”. www.jitterbuzz.com.
2. ^ “Model Flying Machines”. geocities.com. Archived
from the original on 28 October 2009.
3. ^ Testing Commercial Rubber – R.J. North, Model Aircraft magazine, Feb 1961
4. ^ “Archived copy”. Archived from the original on 29 June 2008. Retrieved 23 October 2007.
5. ^ AMA. “AMA Documents – Turbines”.
AMA. Retrieved 5 October 2012.
6. ^ “MAS.865 2018 How to Make Something that Makes (almost) Anything”. fab.cba.mit.edu. Retrieved 21 January 2022.
7. ^ Keith Lawes. “The Rotating Cylinder Valve 4-stroke Engine (SAE Paper 2002-32-1828)” (PDF).
Archived from the original (PDF) on 12 November 2011. Retrieved 3 January 2012.
8. ^ “National Miniature Pylon Racing”. nmpra.net. NMPRA. Retrieved 6 July 2015.
2. RCadvisor′s Model Airplane Design Made Easy, by Carlos Reyes, RCadvisor.com, Albuquerque,
New Mexico, 2009. ISBN 9780982261323 OCLC 361461928
3. The Great International Paper Airplane Book, by Jerry Mander, George Dippel and Howard Gossage, Simon and Schuster, New York, 1967. ISBN 0671289918 OCLC 437094
4. Model Aircraft Aerodynamics,
by Martin Simons, Swanley: Nexus Special Interests, 1999. 4th ed. ISBN 1854861905 OCLC 43634314
5. How to Design and Build Flying Model Airplanes, by Keith Laumer, Harper, New York, 1960. 2nd ed., 1970. OCLC 95315
6. The Middle Ages of the Internal-Combustion
Engine, by Horst O. Hardenberg, SAE, 1999. ISBN 0768003911 OCLC 40632327
7. Model Airplane Design and Theory of Flight, by Charles Hampson Grant, Jay Publishing Corporation, New York, 1941. OCLC 1336984
8. Pulling Back the Clouds, by Mike Kelly,
Limerick Writers’ Centre Publishing, Ireland, 2020. ISBN 9781916065383

Photo credit: https://www.flickr.com/photos/pr1001/3485767306/’]