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Foamflyer's RC Airplanes
Making Sense of the Jargon

1/2A Small glow motors less than 0.15 cubic inches, including the popular .049's.

2s3p Nomenclature for lipoly batteries, two in series, 3 in parallel. Series increases voltage, parallel increases milliAmps.

2-Stroke An engine with two strokes per revolution. 2-Strokes are more powerful but noisier than 4-strokes, but have fewer moving parts and are less expensive.

4-Stroke An engine with four strokes per revolution. 4-strokes have more torque and are quieter than 2-strokes, but have more moving parts and cost more.

A/R/E/T/F/S Nomenclature for describing control functions on a plane. The order is unimportant. Ailerons, Rudder, Elevator, Throttle, Flaps, Spoilers.

AGL Above Ground Level. Altitude of a plane measured with the ground as zero.

Aircore Coroplast.

AM Amplitude Modulation, a form of radio frequency.

Angle of Attack The angle at which a wing moves through air, also seen as "AOA". Wings generate lift at particular AOA's depending on the airfoil. Flat-plate wings generate lift purely by AOA.

AP Aerial Photography, taking still or video pictures from a plane.

ARC Almost Ready to Cover, a mostly pre-built plane without covering.

ARF Almost Ready to Fly, a mostly pre-built plane.

AUW All Up Weight, the weight of the plane finished and ready to fly.

AWARF All Wood Almost Ready To Fly - a mostly pre-built plane made of balsa wood.

B1RD (Bee One Are Dee) A bird that is mistaken as an airplane, usually by little kids.

Barn Door Ailerons Ailerons with a large area compared to the rest of the wing.

BEC Battery Eliminator Circuitry - A function of most ESC's where battery voltage is monitored, allows the use of a single battery pack to operate the motor and radio system.

BL BrushLess motor.

BluCor Same as Fan Fold Foam. Foam product by Dow, well-suited as a construction material for model airplanes. Is actually used as floor insulation.

Brushless Type of electric motor that does not use brushes to conduct electricity inside. These motors are more powerful than brushed motors in part due to less friction.

C/10 Nomenclature for a charge rate, in this case 1/10th of the capacity.

C/A Cyano-Acrylate glue (super glue).

Can Motor An inexpensive ferrite motor.

Carbon Fiber Any number of extremely strong and lightweight products (tubes, rods, mats) for strengthening planes. See Composite Structures Technology.

Cartoon Scale Planes that have mis-proportioned dimensions in a comical way, but still fly.

cc Cubic Centimeters.

Cell A single unit of a battery pack.

CG Center of Gravity - The balance point of a plane.

Chord The length of an airfoil, the distance from the leading edge to the trailing edge, parallel to the direction of flight in most cases.

Ci Cubic inches. Sometimes seen as Cu. In.

CL Control Line. Used to be called "U Control". Flying a plane around in a circle with cables.

COG Same as Center of Gravity.

Coroplast A strong lightweight plastic material in varying thicknesses and colors used to strengthen planes. Is actually used in a number of applications, especially signs.

Crunchie Any plane (usually gliders) that are made from a hard molded material (plastic, fiberglass, carbon, etc).

Cu. In. Cubic inches. Sometimes seen as Ci.

DD Direct Drive - Spinning a propeller with a motor with no gearbox.

De-twigging Pulling sticks and branches out of a foam wing after a landing.

Depron A relatively strong lightweight foam. See Depron USA.

Discus Launch Method of throwing a glider, similar to throwing a discus. DLG's have pins or handles at one wingtip that allows this method of launch.

DLG Discus Launched Glider.

Down Thrust The downward angle of a motor, usually to adjust for the wing's angle of incidence or other misalignment. Downthrust is typically only 2 or 3 degrees.

DR Dual Rate control function on a transmitter, allows the setting of a "mild" and "wild" response.

DS Dynamic Soaring.

DSM Digital Spectrum Modulation, a frequency modulation, based on an optimized version of Direct Sequencing Spread Spectrum, DSM offers pure digital control providing an impenetrable radio link that's immune to all types of interference.

EDF Electic Ducted Fan. A small diameter propeller (fan) inside a duct, used in "jets".

Elapor Type of durable foam, similar to EPP, used in planes by Multiplex.

Elevons Control function combining elevator and ailerons, used on flying wings.

EPE Expanded PolyEthylene - A very resilient crush-proof foam similar to, but not as popular as, EPP.

EPP Expanded PolyPropylene - A very resilient crush-proof foam used in slope soarers and combat models.

EPS Expanded PolyStyrene - Styrofoam - An inexpensive easily-worked foam, lighter in weight but not as strong as EPP.

EPS Electric Power System.

ESC Electronic Speed Control.

Escapement Old mechanism used on early RC planes before servos.

EXP Exponential control function on a transmitter, allows a non-linear resonse.

Ferrite Iron, referring to iron magnets in an electric motor, as opposed to rare earth magnets. "A ferrite motor".

FF Free Flight - A plane having no radio control, with or without propulsion.

FFF Fan Fold Foam - Same as BluCor. Foam product by Dow, well-suited as a construction material. Is actually used as floor insulation.

Flapperons Control function combining flaps and ailerons.

Flutter An occilation in a control surface producing a characteristic buzzing sound, caused by sloppy linkages and/or too much airspeed. Will very quickly rip a model plane apart. You do not think to youself "cool sound" and try it again!

FM Frequency Modulation, a form of radio frequency.

Foamie Any plane constructed of foam.

Former A structural part of an airframe, like a wall or bulkhead inside the fuselage. Stringers help hold the formers in place and in alignment.

Full House Old term to describe a plane that had full control, such as throttle, ailerons, elevator, and rudder. Early RC planes only had rudder control which was not "Full House".

G Geared - Spinning a propeller with a gear reduction drive.

Gas Gasoline - Planes with gasoline-powered engines. Related old term is "Gas Job" for any plane with a gasoline-powered engine.

Glide Ratio The ratio of forward movement compared to downward movement. In other words, how well a plane glides! For example, if a glider flies forward one foot and loses 1 inch of altitude, the glide ratio would be 12:1.

Glow Internal cumbustion engines that use glow fuel and glow plugs.

GU11 (Gee-You-Eleven) A bird (gull) that is mistaken as an airplane, usually by little kids. There is also a "C" version of the GU11.

GWS Grand Wing Servo.

Hershey Bar Wing A wing with a constant chord, whose planform is rectangular, resembling a Hershey bar.

HLG Hand Launched Glider.

HOC Hot Off Charger - A battery pack in a peaked state.

IFO Indoor Flying Object available from WildRC.

Incidence The angle of the wing or stabilizer relative to the thrust line. Can be positive or negative.

IPS Indoor Power System - Designation for small motor / gearbox / prop systems by GWS.

Kv Essentially the RPM per volt rating of a motor. If the Kv is 3400, and you apply 12 volts to the motor, it would theoretically turn at 40,800 RPM.

LHS Local Hobby Store.

LE Leading Edge - The front edge of a wing or surface.

LG Landing Gear.

Li-ion Lithium-Ion batteries. Never charge li-ion or lipoly cells with a NiCd or NiMH charger!

Lipoly Lithium-Polymer batteries, the new technology - lots of miiliamps for very light weight, but at more cost. Never charge li-ion or lipoly cells with a NiCd or NiMH charger!

Lipo Same as Lipoly.

LVC Low Voltage Cutoff - The voltage of a battery pack at which the BEC will start.

MAC Mean Aerodynamic Chord - The average of the root chord and tip chord on a wing. Most airplanes must balance at 25% to 30% of the MAC.

mAh Milliamp-hours, the capacity of a cell or battery pack, how many milliamps (one-thousandth of an Amp) can be delivered in one hour.

Maiden The first flight of a new plane, as in maiden flight.

Mixing Mixing control functions together, as in mixing elevator and ailerons to make elevons. Mixing can be done electronically or mechanically.

MSL Mean Sea Level. Altitude of a plane (or elevation of a hill in this case) measured with sea level as zero.

NiCd Nickel-Cadmium batteries. Never charge NiCd or NiMH cells with a li-ion or lipoly charger!

NiMH Nickel Metal Hydride batteries. Never charge NiCd or NiMH cells with a li-ion or lipoly charger!

Nitro Nitromethane.

PCM Pulse Code Modulation, a form of radio frequency.

Pack Battery Pack.

Peak To Peak a battery pack, or get it to very full capacity.

Planform The shape of a wing when viewed from the top.

Prop Propeller.

Proportional Where the control surface moves the same distance as the control stick on the transmitter. Before proportional control most controls were either "on" or "off", meaning either neutral or full deflection. Also "Fully-Proportional".

PSS Power Scale Soaring. Slope planes with no motor that resemble full-size aircraft.

Puller A plane with the propeller in the front, sometimes referred to as "Tractor".

Pusher A plane with the propeller in the back.

Rare Earth Magnets Magnets in electric motors comprised of Cobalt and/or Neodymium, as opposed to iron. Rare earth magnets are much stronger than iron ones, so motors with these magnets are more powerful.

RC Radio Control - Controlling a plane with radio frequency (AM, FM, PCM).

Right Thrust The right angle of a motor, usually to adjust for motor torque. Right thrust is typically only 2 or 3 degrees. Multi-motor planes typically need a little right thrust, unless the propellers are counter-rotating.

ROG Rise (or Rotate) Off Ground - Taking off from the ground.

Root The airfoil near the center of a wing, which is bigger than the tip chord if the wing is tapered.

ROW Rise (or Rotate) Off Water - Taking off from water.

RPV Remotely Piloted Vehicle. In a sense, all RC planes are RPV's.

Ruddervators Control function combining rudder and elevator, like those used on V-tails.

Rx Receiver.

Safe Wing A wing modification developed by NASA to reduce stalls, consisting of an extended and "drooped" leading edge surface. Develops a vortex at the joint between the Safe Wing surface and the rest of the wing, which reduces tip stalling.

Ship Old term for any model plane.

Slimer A model airplane with an internal combustion engine.

Sloping Flying Slope Soarers.

Spoilerons Control function combining spoilers and ailerons.

SS Slow Stick - Popular slow flyer plane from GWS.

SS Slope Soaring.

Stab Stabilizer.

Stall When the wing loses lift, usually at low speed. A good plane design is one that will stall straight ahead rather than to the side (a tip stall).

Stall Strips A square or triangular block attached to the leading edge of a wing at the root (each side of the fuselage). At slow speeds, they cause the root of the wing to stall first, which helps prevent a tip stall.

Stick A plane using a stick as the fuselage, as in "Stick Plane". The stick could be balsa, hardwood, carbon, fiberglass, aluminum.

Stick & Tissue Method of plane construction.

STOL Short Takeoff or Landing - Planes designed for, or equipped with high-lift devices.

Stringer A structural part of an airframe, like rods running from the nose back to the tail (longitudinally).

Strip Ailerons Ailerons that run from near the fuselage of a plane all the way out to the wingtips.

Sturdiboard A craft material consisting of a thin piece of foam (similar to Depron), surfaced both sides with heavy paper. Normally too heavy by itself, the paper can be removed, leaving the foam.

Tailerons (also known as Televons) Control function of ailerons on the tail, or stabilizer of a plane.

TD Thimble Drome - Old name used by Cox for small 1/2A glow motors.

TE Trailing Edge - The back edge of a wing or surface.

Throw How far control surfaces move (ailerons, elevator, rudder) in either direction.

Thrust Line An imaginary straight line from the propeller shaft through the plane to the tail.

TIFO Trainer version of the Indoor Flying Object available from WildRC.

Tip The airfoil at the tip of a wing, which is smaller than the root chord if the wing is tapered.

Tiperon An aileron at the tip of a wing, rotating on a pivot. The entire outer surface of the wing panel becomes the aileron, from leading edge to trailing edge.

Tip Stall When a wingtip loses lift, usually at low speeds. A violent tip stall can result in a roll. You always want a wing to stall at the root first.

TLAR That Looks About Right - Building based on experience without taking actual measurements.

T-Tail A stabilizer mounted to the top of a fin, resembling the letter "T".

Turbine A jet engine (compressor).

Turtle Deck The curved area on the top of a fuselage, from cockpit to tail.

Tx Transmitter.

UAV Unmanned Aerial Vehicle. In a sense, all RC planes are UAV's.

UBEC A device that regulates voltage from a motor battery pack down to a lower voltage for the receiver and servos. UBEC is used on higher amp-rated ESC's that do not have BEC.

V-Tail Combining fins and stabilizer, resembling the letter "V". V-Tails use Ruddervators.

Vortex The spiralling air that forms from wingtips in flight, caused by unequal pressure on the top and bottom surfaces of the wing. Usually undesirable sources of drag, and not easily reduced or eliminated.

VTOL Vertical Takeoff or Landing - Planes designed to takeoff and land vertically, like helicopters.

Washout The downward angle or twist of wingtips. Washout is typically only 2 or 3 degrees. Washout can help prevent tip stalling at low speeds.

Whattmeter Device available from Astroflight that plugs in between the motor and battery. Displays battery amps, volts, and calculates watts. A very useful device for finding optimum power systems.

WL Wing Loading - How much weight the wing has to support, usually measured in ounces per square foot. Lower wing loadings fly slower, higher fly faster.

WOT Wide Open Throttle.

WS Wing Span - The distance from one wing tip to the other.

Zapping Charging a new cell with a sudden powerful burst of electric charge, which chemically reduces the internal resistance making it more efficient, a "zapped cell".


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by FoamFlyer