Model Airplane News – August 2019

32 ModelAirplaneNews.com

GEAR GUIDE

ABC: Term that refers to the materials

used in the engine. An ABC engine is

one with an aluminum (A) piston that’s

fi tted inside a brass (B) sleeve that’s

chrome (C) plated.

Adverse yaw: Yaw generated when

the ailerons are used. Th e lifting wing

generates more drag, causing an

airplane to yaw (turn) out of the turn.

Aileron: Roll control surface.

Ampere (amp) (A): Standard unit of

electric current.

AoA (angle of attack): Angle diff erence

between the wing chord line and the

relative wind.

Base leg: Portion of the landing

pattern 90 degrees to the fi nal

approach.

Battery eliminator circuit (BEC):

Circuitry that allows the battery that

runs the motor to also power the

receiver and the servos.

Brushed motor: Older, traditional type

of electric motor where brushes make

contact between the rotor and the

stator.

Brushless motor: Popular electric

motor now used to power RC electric

aircraft. More powerful than traditional

brushed motors.

Capacity: Measure of how long you

can draw a specifi ed current from a

battery. Measured in amp hours (Ah)

or, more commonly for the scale of

equipment used for electric fl ight, in

milliamp hours (mAh).

Climbout: Gain in altitude after takeoff.

Con rod: Short for “connecting rod.”

Connects the piston to the crankshaft.

Crosswind leg: Portion of the traffi c

pattern that’s 90 degrees to the

runway and directly opposite of the

base leg.

Current: Flow rate of electrical energy

measured in amps.

Dihedral: Upward angle of the two

wing panels relative to the fuselage.

Contributes to the model’s roll stability.

Doublers: Items glued to the inside of

the fuselage sides to add strength in

specifi c, high-stress areas.

Downwind leg: Portion of the traffi c

pattern that is fl own in the opposite

direction of the wind. Th e downwind

leg is directly opposite the upwind leg

and parallel to the runway.

Drag: Force that acts to slow down

the airplane.

Elevator: Pitch control surface.

Engine case: Main body of the engine.

Final approach: Upwind portion of

landing pattern after base leg and just

before fl are and landing.

Firewall: Engine is attached to this

part, and sometimes the model’s

nosewheel is also secured to it.

Flare: Gradual increase in pitch angle

to bleed off excess airspeed just

before landing.

Formers: Internal vertical structures

that support the sides and give the

fuselage its strength and rigidity.

Fuel mixture: Mixture of air and fuel

drawn into the engine through the

carburetor.

Fuselage: Main body of the airplane.

All the other parts and components

are attached to it. Th e fuselage houses

most of the airborne radio equipment

and the powerplant.

Gravity (G-force): Force that pulls

down on the model, measured in Gs

or G-forces.

Head: Part on top of the engine that is

usually bolted in place. At its center is a

threaded hole for the glow plug.

Heading: Actual direction the model

travels over the ground, not the

direction the model is pointing.

Horsepower (hp): Measure of the rate

of work—33,000 pounds lifted one

foot in one minute, or 550 pounds

lifted one foot in one second. Exactly

746 watts of electrical power equals

one horsepower.

Leading edge (LE): Very front edge of

the wing. It is rounded to allow the air

to fl ow easily over both the top and

bottom surfaces.

Lift: Th e force exerted on the top of a

moving airfoil as a low-pressure area,

which causes a wing to rise.

LiPo: Term that stands for “lithium-

ion polymer.” Th e most modern kind

of battery pack that’s used in electric

aircraft.

Longeron: Long, sticklike part that

runs from nose to tail. It supports and

strengthens the fuselage structure.

mAh (milliamp hour): Measure of a

battery’s total capacity. Th e higher the

number, the more charge a battery

can hold and, usually, the longer a

battery will last under a certain load.

Main spar: Part that gives the wing its

longitudinal strength. It runs from the

wing root (middle of the wing) all the

way to the tip.

Ni-Cd: Abbreviation for nickel-

cadmium battery cells.

NiMH: Abbreviation for nickel-metal-

hydride battery cells.

Pitch: One of the three axes in fl ight,

this specifi es the vertical action or the

up-and-down movement.

Port: Channel or opening inside the

engine that guides and transfers

the fuel and air mixture from the

crankcase to the combustion

chamber. Opened and closed by the

piston’s up-and-down motion.

Power: For electric models, this is a

product of voltage and amps, and it is

measured in watts.

Rib: Part that gives the wing its

cross-section shape; the shape is also

known as an “airfoil.” It is this shape

that generates the lifting force that

allows airplanes to fl y.

Roll: One of the three axes in fl ight,

this specifi es the action around a

central point.

rpm (revolutions per minute): Th e

number of times an object completely

rotates (360 degrees) in one minute.

Rudder: Part that controls the model’s

yaw (nose-left and nose-right move-

ment). Defl ecting the rudder swings

the nose left or right while in fl ight.

Rudder input also steers the model on

the ground while taxiing and is used

to correct a fl ight condition known as

“adverse yaw.”

Sleeve: Inside cylinder lining that

houses and guides the piston. It is

a separate piece from the engine

case and has openings or ports

cut into its side. Th ere are some

engine designs that do not have a

separate sleeve.

Stall: Sudden loss of lift when

the angle of attack increases to a

point where the fl ow of air breaks

away from a wing or airfoil, causing

it to drop.

Stringer: Similar to a longeron but is

typically small and used to support

the model’s covering, which gives the

fuselage its shape.

Taxi: Travel across the ground.

Th rust: Force that pulls (or pushes) a

model forward. Th rust is created by

the propeller as the engine or motor

spins it. A propeller has an airfoil-

shaped cross-section.

Torque: Twisting force created by the

engine spinning a propeller. Th e force

acts in the opposite direction of the

rotating propeller.

Trail edge (TE): Th e tapered, most aft

edge of the wing. More shapely and

smaller than the LE to help the air

passing over and under the wing to

come back together with a minimum

of drag or turbulence.

Trim: Secondary transmitter controls

to adjust the amount of rudder,

elevator, and throttle.

Upwind leg: Portion of the traffi c

pattern that is fl own into the wind.

Th e upwind leg is directly opposite

the downwind leg and parallel to

the runway.

Voltage (V): Unit of electromotive

force that, when applied to con-

ductors, will produce current in the

conductors.

Watt (W): Th e amount of power

required to maintain a current of

1 ampere, at a pressure of one volt,

when the two are in phase with each

other. One horsepower is equal to

746 watts. Watts are the product of

volts and amps.

Wing: Part that produces lift.

It consists of several parts and

subassemblies.

Wing saddle: Part of the fuselage that

the wing rests upon. Th e wing saddle

is usually also the main opening for

access to the radio equipment.

Wingtip: Part at the very end of the

wing panel. Mostly cosmetic.

Ya w : One of the three axes in fl ight,

this specifi es the side-to-side

movement of an aircraft on its vertical

axis, as in skewing.

GLOSSARY OF AVIATION TERMS

Air Age Media ....................................... 30

APC ............................................................ 20

Atomik RC .............................................. 23

Bat-Safe .................................................. 22

Blade ........................................................ 20

Byron Originals .....................................27

DLE Engines .......................................... 22

E-flite ...................................................16–17

FMS ......................................................16–17

FrSky RC .................................................. 22

Graupner ..................................20, 23–24

Hangar 9 ..................................................19

Krill Models ............................................19

Marine Jet USA ............................. 22, 27

Morgan Fuel .......................................... 28

Pilot-RC.....................................................19

PowerBox Systems............................ 24

Rage R/C .......................................... 16, 18

Ram RC Models ................................... 26

Seagull Models .....................................19

Skymaster USA .....................................18

Southwest Systems ..........................27

Spektrum ........................................22, 24

Sullivan Products ....................... 26, 28

Tru-Turn ................................................... 23

VQ Warbirds ............................................18

Warbird Pilots ...................................... 26

Wildcat Fuels ........................................ 28

Wing Tote................................................ 30

Xoar and Falcon ................................... 23

BRAND INDEX