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Model Aircraft Glossary



ConcordeOne of the most famous passenger aircraft of all time and the perhaps one of the most elegant of TSR 2fighters that never made it into production from the same stable.


Term describing the amount of play between gears, or gear mesh. If too loose, the gear can slip, or strip the teeth. Too tight, and excessive wear is caused.

B. A. Threads

Clearance and tapping drill sizes. more......

Ball Race

The inner or outer rings that form the tracks for the balls in a ball-bearing.

Balsa Wood

Balsa wood comes from the West Indian Corkwood tree (Ochroma lagapus). It is used in the construction of model aircraft as it is a very light and easily cut and formed. When selecting balsa wood it is important to consider the intended application as it varies considerably in density and hardness. more...


Weight carried by an aeroplane to increase the Wing Loading or adjust the centre of gravity.

Ball Link

Connection using a ball, and a link which rotates on the ball. Used to connect the servo to a control surface or lever.

See also: Servo.


A lighter than air craft. The Montgolfier brothers made the first flight in a hot air balloon in 1783.


A natural material with a great strength to weight ratio. It was used in the early construction of wings and fuselages.


A turn made in flight with one wing lip lower than the other.


In the early years of aviation pilots gave people rides in an aircraft and performed aerobatics for a fee. They were known as barnstormers.

Barry Smith

Acro AdvancedAcro Advanced

Base Load Antenna

A rigid, short antenna mounted to the model. Used to replace the longer receiver antenna.


A means of storing electrical power chemically.

Reference: Electrochemistry Glossary -

Battery Eliminator Circuitry (BEC)

Allows receiver to draw power from a main battery pack, eliminating the need for (and weight of) a receiver battery.

BB (Ball-Bearing)

This is used to designate that the crankshaft in an IC engine is supported by ball-bearings. Cheaper/smaller capacity engines normally have phosphor-bronze bearings. Ball-bearings allow an engine to run smoother and last longer.

Beam Mount

Engine mounting consisting of a plate or beams to which the engine is mounted by means of the lugs on either side of the crankcase.


The supports that are used to hold a rotating shaft in position. Small internal combustion engines such as those used to power model aircraft often use phosphor bronze for the main crank bearings. As well as holding the crankshaft in-line and reacting the thrust from the propeller they form a seal between the crankshaft and the crankcase so allowing the air-fuel mixture in the crankcase to be compressed (two-stroke engines).

Beaufort Scale

In 1805 Admiral Beaufort drew up a scale of wind strengths related to commonly observable phenomena. more......


Beech StaggerwingThe Beech 17 Staggerwing is one of the most beautiful biplanes ever built. It won a number of air races before being used by the USAAF as a personnel and utility transport during WWII.

If you would like to see more pictures our photographic library is available on

Bell X1

Bell X1On the 14 October 1947 the Bell X1 was the first aircraft to break through the sound barrier flown by Captain Charles E Yeager. The X1 was launched by a Boeing B29 at 30000 feet, once released the rocket motor was fired and it begun it's ascent to 42000 feet and 670 mph (Mach 1.015).

If you would like to see more pictures our photographic library is available on

Bell and Hiller

Control system used in helicopters. Changes pitch of blades in relation to their position via a swashplate. A flybar with paddles is used to gain responsiveness. The two systems are linked with Control Levers.


The pivoted wood, metal, or plastic arm which converts the motion of the control lines to up-and-down movement of the elevators in a control line model aeroplane.

See also: Servo.

Biconic Geometry

Two cone structure configuration.


What occurs when the friction at a joint is stronger than the linkage.


Pitts Special S1An airplane with two sets of wings, one on top of the other. Historically the biplane configuration was used as it improves the bending stiffness of the wing that was otherwise difficult to achieve in early monoplane designs.

Blade Balance

Rotor blades that are equal in weight will balance each other. Unbalanced (unequal in weight) rotor blades will cause model shake and instability in flight.

Blade Damper

A device (spring, friction, or hydraulic) installed on the vertical (drag) hinge to diminish or dampen blade oscillation (hunting) around this hinge.

Blade Flapping

The movement of the rotor blades in a vertical plane (up and down) due to their attachment to the rotor hub by a horizontal hinge.

Blade Incidence or Pitch

The blade angle of attack in reference to the rotor disk plane, or the angle from zero lift line to the plane of disk rotation.

Blade Loading

The load placed on the rotor blades of a helicopter, determined by dividing the gross weight of the helicopter by the combined area of all the rotor blades.

Bleriot, Louis

On 25 July 1909 Louis Bleriot crosses the English Channel from Baraques (nr Calais, France) to Dover Castle (England) in a Bleriot XI a distance of 231/2 miles in 36 minutes and 30 seconds winning the 1000 prize offered by the Daily Mail.

See also: Chronology of Flight.

If you would like to see more pictures our photographic library is available on

Blowdown Wind Tunnel

An open-circuit wind tunnel in which gas stored under pressure is allowed to expand through a test section to provide a stream of gas or air to test a model. The gas then escapes into the atmosphere or into an evacuated chamber. Test times are finite and usually last from a few seconds to minutes.


Boeing StearmanWilliam E. Boeing formed the Pacific Aero Products Corporation that on 26 April 1917 became The Airplane Corporation. Nowadays Boeing are known for their airliners, the 707 sparking the airliner revolution in 1958 when Pan American put it into service across the Atlantic.

If you would like to see more pictures our photographic library is available on


A wood tube or strip that extends rearward from the wings or from a short fuselage to support the tail surfaces.

Boundary Layer

The relative speed of airflow varies with the distance away from the surface. Right next to the surface there is no measurable relative motion. The thin boundary layer is slowed down by the presence of the surface.

Reference: Aerodynamics Glossary -

Bracing wire

Boeing Stearman - Bracing wires used to between wing planes.A solid steel wire used to support the structure of an airplane's wings or fuselage. Turnbuckles are often used to tension the wires. In the early days of aircraft design the biplane with bracing wires and struts was the strongest design. The disadvantage of bracing wires is drag. Although the wires may be small in diameter the drag of these is a significant percentage of the overall drag of the airframe.


Bristol F2b FighterThe Bristol F2B Fighter was a considerable fighter withstanding severe punishment. 5252 were built and served with 14 foreign air forces.

First flown: 9 September 1916

Engine: 275hp Rolls-Royce Falcon III V12, or any one of another 16 engines ranging in power from 120 to 400hp.

Dimensions: Wingspan 11.9 m , Length 7.9 m , Height 2.98 m

Performance: Maximum speed 125 mph , Service ceiling 20000 feet.

Armament: One 0.303in Vickers machine gun fixed on top centreline with synchronising gear, one or two 0.303in Lewis mounted on Scarff ring on rear seat, plus up to twelve 20lb bombs.

Bristol BoxkiteThis particular Boxkite is a replica that was originally made for the film "Those magnificent men in their flying machines". It is still flown by the Shuttleworth collection.

Bristol BlenheimBristol Blenheim a WWII light bomber. Initially designed as an executive transport aircraft carrying 6 passengers plus a pilot and designated Type 142. With retractable undercarriage and stressed skin it was capable of 240mph, outperforming all of the fighters in service with the RAF in 1935.

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The first aircraft produced by Bucker was the Jungmann that was first flown in 1934.

Bucker JungmannJungmann One of the great training aircraft.

Bucker JungmeisterJungmeister From the success of the Jungmann, Bucker decided to produce the Jungmeister at a new factory. Generally it is very similar to the Jungmann, but smaller making it very aerobatic. Jungmeister means young champion.

If you would like to see more pictures our photographic library is available on

"Buddy" Box

Two similar transmitters that are wired together with a "trainer cord." This is most useful when learning to fly -- it's the same as having dual controls. The instructor can take control by using the "trainer switch" on his transmitter.


A former within the fuselage used as internal support for longerons, sheet sides, stringers and so on. Open triangulated structures are often used in the rear section of a fuselage to reduce weight and so allow the centre of gravity to be achieved without adding ballast.


An elastic chord used to launch gliders. A number of different types of bungee are available with different characterisitcs.


A free-flight aircraft, either engine-assisted or a glider, which uses a quarter outside loop to effect the transition from climb or high-energy tow-launch into the glide, and thus maximise the possible altitude and hence duration.

Butterfly or Crow

A mix which activates up flaperons and down inner-most flaps for gliding speed control without spoilers or airbrakes.