RC Glossary of Terms

BHP

Brake horsepower. A measurement standard used by manufacturers to help consumers compare engines. NOTE: BHP is measured at the maximum operating RPM of the engine, which may not be the RPM level at which your engine will provide maximum life and consistent performance.

Binding

Occurs when the friction at a joint is stronger than the linkage.

Binding Process

A proprietary combination of gyros, sensors, and software that helps to stabilize and control the heading of RC aircraft models.

Blind Nut:

(Also called a T-Nut) A pronged nut that is pulled into a surface such as wood so that it cannot turn when a bolt is tightened into it. Blind nuts are typically used in situations where it would be impractical to use a tool, such as pliers, to hold the nut while the fastener is being tightened.

Boundary Layer:

The thin layer of air immediately adjacent to a body moving through the air.

Buddy Box:

Training method utilizing two transmitter control boxes, linked together. The trainer radio has override control, which the instructor uses to take control when the trainee loses control or becomes disoriented.

Bulkhead

A vertical former inside a fuselage.

Butterfly

Also known as crow. A mix which activates up flaperons and down inner-most flaps for gliding speed control without spoilers or airbrakes. Crow (or butterfly) is only used for landing or perhaps for diving out of a thermal.

CA (cyanoacrylate):

A modern hobby adhesive that cures very quickly.

Cabane

A strut attaching a wing to the fuselage when the wing is above the fuselage such as biplanes and parasol aircraft.

Camber

If you draw a line through the center of the airfoil that's exactly half-way between the top and bottom surface, you get the mean airfoil line. Depending upon the airfoil, it can be straight or curved. This curve is called the "camber" of the airfoil. If it has a lot of curve, the airfoil is said to be "highly-cambered".

Canard

An aircraft having the horizontal stabilizer forward of the main wing rather than in the conventional position behind it. Canard aircraft are theoretically more efficient because both the horizontal stabilizer and the wing provide upward lift. The horizontal stabilizer of a conventional aircraft provides downward lift to stabilize the aircraft resulting in an overall decrease of the aircraft's total lift.

Carburetor

The part of the engine which controls the speed or throttle setting and lean/rich mixture via setting of the needle valve.

Center of Gravity (CG)

The balance point of a model airplane. For modeling purposes, this is usually considered the point at which the airplane balances fore to aft. This point is critical in regards to how the airplane reacts in the air. A tail-heavy plane will be very snappy but generally very unstable and susceptible to more frequent stalls. If the airplane is nose heavy, it will tend to track better and be less sensitive to control inputs, but will generally drop its nose when the throttle is reduced to idle. This makes the plane more difficult to land since it takes more effort to hold the nose up. A nose-heavy airplane will have to come in faster to land safely.

Center of Lift (COL)

The location on the top of the wing where the sum of all lifting forces is located.

Centrifugal loads

(propeller) are very predictable, given rotational speed and mass density distribution of a blade. Their contribution to total stress is relatively small.

CG

Center of Gravity. Describes a central point in a given body, where all weight is considered to be concentrated. A central balance point.

Chandelle

A very steep climbing turn where the airplane makes a 180° change of direction.

Channel

The number of functions your radio can control. Example: A 7-channel radio has 7 available servo slots used for separate control surfaces or switches. These channels can also be mixed on many radios, for such functions as collective, which increases pitch when throttle is increased.

Chicken Stick

A hand-held stick used to "flip start" a model airplane engine.

Chord

The "depth" of the wing, its distance from leading edge to trailing edge. One of the components used to determine wing area. May vary from root to tip.

Clevis

The Clevis is a small fastener at the end of a pushrod, usually made from nylon or metal, which connects the pushrod to the control horn. Clevises may frequently be referred to as links.

Collet

A slotted jaw that allows a limited range of bits to be placed in a tool such as a router, moto-tool, or pin vice.

Coning

This effect is the bending of the rotor or propeller blades when stressed.

Control Linkage

Any linkage transmitting servo movement to a control surface.

Control Surface

A movable surface such as elevator, rudder, and aileron.

Conventional Tail

A Conventional Tail is one with the stabilizer mounted directly on the fuselage and is the usual configuration of an aircraft. These are the simplest to construct and seem to be most popular.

Covering

The covering of an aircraft is the skin which is applied to the airframe, closing it in. On R/C aircraft, it is commonly a fabric or plastic film which is heat applied with an iron. Plastic covering, once applied, gives a durable, shiny finish and requires no further treatment. Fabric covering usually requires a layer of paint to finish it and make it resistant to the exhaust of the engine. Covering materials come on a roll and in many different colors and may be cut to rough shape before being ironed onto the airframe.

Cowl or Cowling

The large molded fairing around an engine. It serves two purposes: It helps the airflow go smoothly around the front of the airplane and also provides a proper path for cooling air around the engine.

Crab

When an aircraft flies at a sideways angle relative to the direction being traveled. Can be caused by a crosswind or may be flown intentionally to reduce altitude without increasing forward airspeed while on landing approach.