RC Glossary – About RC Airplanes

We’ve put together this rc glossary for your perusal. Refer to it anytime you hear a term or phrase that has to do with this hobby that you don’t understand.

Adjustable Travel Volume (ATV) -In order to help you set the control action on your plane the way you like, this lets you set the maximum travel of a servo to either side from its center position.

Adverse Yaw -This is the tendency of the airplane to yaw in the direction of the wing with the lowered aileron, which is the direction opposite the turn being performed. This is most pronounced at slow speeds and high angles of attack, such as during takeoff or when you’re trying to stretch out your landing. You can minimize this tendency by coordinating your turns using both the aileron and rudder controls.

Ailerons -The movable part of the trailing edge of the main wings extending from the wing tips in, either part or all the way to the fuselage. When you move the control stick to the left, the left aileron goes up forcing the left wing down and the right aileron goes down forcing the right wing up. This makes the airplane bank and therefore turn to the left and vise versa. One hint to check proper aileron direction of travel, just remember which ever way you push the control stick, that aileron should go up. If it doesn’t, flip the servo reversing switch on your radio and that should fix it.

AMA -Academy of Model Aeronautics. The official association for model aviators in the U.S.

Angle of Attack – The angle between the chord of the airfoil (wing) and the relative wind. For example as you pull back on the stick to climb, your angle of attack increases.

ARF -Almost ready to Fly. Models that come from the manufacturer with most of the construction already finished.

Buddy Box (Trainer System) -This is when you connect two compatible radios (transmitters) together with a special chord. Used by an instructor and a student. The instructor can take over control of your airplane if you get in a bind and need help to recover.

Boring Holes In The Sky -When you’re just out to have a ball flying, without planning out in advance what you’re going to do.

CA (Cyanoacrylate) -An adhesive used extensively in model building. Mostly used for wood models. Definitely not for Styrofoam. Cures quickly.

CG (Center of Gravity) -The point between the nose and the tail where the plane will balance. This is important because if the CG is too far aft, the plane will be unstable and will stall much easier. It could also be harder or impossible to recover from a stall. If the CG is too far forward, the stall speed increases. This could cause problems during takeoff or landing. It will also require a higher speed on takeoff before the plane will rotate.

Chicken Stick -A stick used to flip start an rc airplane engine by hand.

Clunk -A heavy, usually filtered fuel pickup in the fuel tank of your plane that keeps the fuel line in the fuel.

Control Horn -A bracket that is mounted on a part of the model where the pushrods are attached.

RC Glossary   About RC Airplanes

Control Linkage -Some type of connection between the servo and the control surface. Usually a pushrod.

Control Surface -The movable surfaces on the airplane that control flight such as ailerons, elevator and rudder.

Coupling (Control Mixing) -Electronically coupling two radio control channels together at the transmitter when only one channel is activated. A lot of giant scale models need a combination of rudder and ailerons to turn properly.

Dead Stick -When the engine quits running and you have to glide to a landing.

Differential Throw -This is the term used to describe when the ailerons are set up so that they don’t deflect as far down as they do up. This helps counteract adverse yaw.

Dihedral -The upward angle of the wings from the aircraft fuselage to the wing tips. The greater the dihedral, the more stable the airplane will be as it is always trying to center itself. (not a good thing if you’re into aerobatics)

Down Thrust -When the engine is mounted on the airplane at a slightly downward angle. This is used to overcome the tendency of airplanes with flat bottom wings, to climb.

Electric Starter -A hand-held electric motor, powered by a 12 volt battery that is used to start an rc airplane.

Electronic Speed Control (ESC) -An electronic module mounted in the airplane that controls the speed of an electric motor. (like a throttle)

Elevator -The movable part of the trailing edge of the horizontal stabilizer that controls the pitch of the airplane (climb and descent). If you pull back on the control stick, the elevators move up forcing the tail down. When the tail goes down the nose goes up and the airplane climbs. Inversely, if you push the stick forward, the opposite happens and the nose goes down causing the airplane to descend.

Endpoint Adjustment -This is a feature on some radios that allows you to adjust the length of servo travel in one direction. If your plane rolls faster one way than the other, this can fix the problem.

Epoxy -A high strength two part glue that consists of resin and hardener.

Expanded Scale Voltmeter (ESV) -A meter that allows you to read the voltage of either the transmitter battery pack or the onboard receiver battery pack.

Field Charger -A fast battery charger that is set up to work from a 12 volt battery like the one in your field box or your car.

Flaps -The section at the trailing edge of the main wings between the fuselage and the ailerons that can be lowered to produce more lift or more drag (depending on how far down they are lowered). These are usually found on more advanced models.

Flare -The part of the landing where the pilot increases the amount of back pressure on the elevator to slow the descent just before touchdown.

Flight Box -A box that makes it easier to carry all of your accessories to the flying field.

Flight Pack -All of the electronic equipment installed in the airplane such as receiver, battery pack, servos, switch harness and possibly electronic speed control.’

Flutter -When your elevator or ailerons begin to oscillate violently in flight. Sometimes this can be so severe that it can actually cause that particular control surface to break off in flight and cause your plane to crash. From the ground this sounds like a low pitched buzzing sound and means, “LAND IMMEDIATELY”. Too much slop in the pushrod connections and control horns or too much hinge gap can cause this.

Frequency Module -Small electronic devices that plugs into the transmitter and the receiver that control which channel number your system operates on.

Fuel Overflow Line -The line from the fuel tank to either the muffler pressure nipple (if it’s a pressurized system) or open to ambient pressure. Like the name implies, this is where the fuel will overflow when the tank is full when fueling.

Fuel Pick Up Line -The fuel line that goes from the fuel tank to the carburetor. It typically has a weight, sometimes called a clunk on the end in the fuel tank to keep the fuel line submerged at all times.

Fuselage -The main body of the airplane from front to back that the engine and wings are attached to.

Glow Plug -A small plug in a gas rc engine that ignites the fuel/air mixture. To start the engine an outside electrical source must be used to heat the filament of the glow plug, then when the engine is running, the glow plug is kept hot by the explosions in the engines cylinder.

Glow Plug Clip -A 1.2 volt battery that attaches to the glow plug for starting. Some of these can be plugged into the power panel on your field box if so equipped.

Grease it on -The term used when you make a nice smooth landing with no bounce.

Hit -When the receiver in your plane picks up a radio signal from another source which causes it to fly very erratically.

Horizontal Stabilizer -The horizontal wings at the tail. They provide pitch stability to the airplane.

Idle Bar Plug -A type of glow plug with a bar across the tip to keep raw fuel from being splashed onto the glow element.

Lateral Balance -The right to left or side to side balance of an airplane.

Leading Edge -The front edge of any wing or stabilizer.

mAh (Milliamp Hour) -The measure of a battery’s total capacity. The higher the number, the more charge a battery can hold and usually, the longer a battery will last under a certain load.

Needle Valve -The adjustment on a carburetor that you use to set the best fuel to air mixture. Some carburetors have separate needle adjustments to set Idle and max throttle.

NiCd -(Nickel Cadmium battery) These are rechargeable batteries that are typically used to power transmitters and receivers.

Nitro (Nitromethane) -A fuel additive that increases an engines ability to idle at low rpm and improves high speed performance.

One Point Landing -A hard crash.

Peak Charger -A charger that shuts off automatically when your battery is fully charged.

Pitch Axis -The airplane axis that is controlled by the elevator. (up and down)

Power Panel -A distribution panel that is mounted on a field box and connected to a 12 volt battery to control accessories like electric starters, glow plug clips and electric fuel pumps.

Programmable or Computer radios -Newer technology radios that have programmable features like preprogrammed maneuvers and multiple plane memory to name just a few.

Prop Pitch -Propellers are designated by two numbers. For example, 11 X 5 means that the props length is 11 inches from tip to tip and the prop will move forward 5 inches in one revolution.

Pushrods -Rigid wires or rods of various material that connect the servos to the control surfaces, throttle etc.

Re-Kitting Your Airplane -Another term for crashing or changing your plane back into a kit.

Receiver (Rx) -The electronic unit in the rc airplane that receives the signal from the radio (transmitter) and relays that signal to the servos through wires. The servos then control the flight control surfaces by the use of pushrods.

Roll Axis -The airplane axis that is controlled by the ailerons. (turns left and right)

RTF (Ready to Fly) -Models that come from the manufacturer almost completely assembled and include all of the components required for flight such as, plane, engine, flight pack and radio (transmitter).

Rudder -The movable surface at the trailing edge of the vertical stabilizer. This allows you to yaw the airplane left or right.

Servo -An electro-mechanical device that moves the control surfaces, throttle or other movable attachments usually through the use of pushrods. The servo receives its signal from the on-board receiver which receives its signal from the radio or transmitter.

Servo Output Arm -The removable arm or wheel that bolts to the output shaft of a servo and connects to the pushrod.

Servo Reversing -This is a feature on your transmitter that lets you reverse the direction the flight control etc. is moving in response to your movement of the controls on the radio.

Solo -Your first flight that ends in a successful landing without any outside help.

Spinner -The nose cone that covers the propeller hub.

Stuffing it in -Yet another term for a crash.

Stall -This is what results when you exceed the critical angle of attack of your model. For example, you’re trying to climb too steep for the forward airspeed of your plane and the wing stops producing lift. The airplane stalls and drops. You must get the nose down and establish forward flying speed again before impact.

Tachometer -A device that optically senses light impulses through a turning propeller and tells you the rpm.

Tail dragger -Type of landing gear. Two main wheels under the wings and a smaller wheel under the tail.

Tip Stall -When only one of your wing tips stalls causing that wing to drop suddenly. This can result in a crash if you don’t have sufficient altitude to recover.

Trainer Airplane -Any rc model airplane designed with the characteristics that make it more stable and easier to fly.

Trailing Edge -The rearmost edge of a wing or stabilizer.

Transmitter (Radio) -The box that the rc pilot holds which sends out signals to the airplane.

Tricycle Gear -Type of landing gear. Two main wheels under the wings and a steerable nose wheel.

Touch and Go -To land and then takeoff immediately without a stop.

Vertical Stabilizer -The part of the vertical tail that does not move. It’s purpose is to provide yaw stability.

Washout -An intentional twist in the wing. This causes the wing tips to have a lower angle of attack than the wing root. This can help prevent tip stalls.

Wheel Collar -The round retaining device that keeps the wheels on the axle.

Wing -The main airfoil on an rc airplane.

Wing Loading -The amount of weight per square foot that must be overcome to provide lift. Take the square inches of the wing and divide that number by 144 to obtain square feet, then divide the total weight in ounces, of the airplane by the wing area (in square feet).

Wing Root -The centerline of the wing where the left and right wing panels are joined.

Yaw Axis -The airplane axis that is controlled by the rudder.

Z-Bend -The Z shaped bend in the wire end of a pushrod that is used to attach the pushrod to a servo output arm.

Z-Bend Pliers -A special type of pliers used for making Z-bends.