Glossary of Terms
Glossary of Terms |
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Term describing style of flying which is characterised by the performance of very specialised aerobatic manoeuvres below the model's normal stall speed. Examples include torque rolls, "walk in the park", harriers, hangers, etc.
Slang abbreviation for flip flop flying. Similar to 3D, but without the finesse.
Number describing degrees in an arc. A 360 represents one full turn through an axis. A 360 turn, for example, is a flat turn where the aircraft does not roll its wings but rather just 'slides' through 360 degrees turning on rudder only.
82 deciBell (Average) This is the maximum recommed noise level measured with a sound meter at 7m from the engine at full throttle see "How to Noise Test a Model Aircraft (The BMFA way)" Noise is measured on a logarithmic scale (I bet when you were in school you thought you'd never use log scales in "real life") so a reduction of 3dB(A) is roughly half the noise!
These letters are used to describe the type of piston and cylinder used in some engines. Aluminium piston. Brass cylinder liner. Chrome coating on the surface of the brass cylinder liner.
A type of plastic often used for vacuum formed components such as cowlings.
American version of ARTF
A Kit where most of the hard and time consuming work has been done in the factory. All of the building and covering of the fuselage, wings and tail plane are done for you, all that is left to be done is join the wings, glue in the tail assembly, install the engine, and radio equipment. This type of kit is becoming very popular and the quality is improving all the time. Having said that I still find ARTF kits with the wrong incidence set on either the wing or the tail plane.
A Kit where most of the wood work has been done in the factory. Most of the building of the fuselage, wings and tail plane are done. You have to cover all parts, join the wings, glue in the tail assembly, install the engine, and radio equipment. This is a good type of kit as you have a lot of the long and tedious work done for you, but you have the choice of making your model aircraft stand out by applying some snazzy colour scheme. This type of kit is not very popular, most people want the speed and convenience or ARTF kits.
High-end feature which adjusts to bring full servo potential within the limits of bind-free servo travel. Ideal for throttle control, or for more effective braking in gas racing.
Allows separate adjustments of maximum servo travel to both sides of neutral. Helps tailor outputs for different control styles.
The BMFA operate a scheme where you are tested to show your level of skill in flying a model aircraft. The first level is known as an "A Certificate". To take the test is free and generally someone in your club will hold an "Examiners Certificate" so talk to them and ask them what is involved in obtaining an "A Cert." Most reputable clubs insist that learners are supervised by and experienced pilot with an "A Certificate" or greater. An "A Cert." is relatively easy to get and just shows you have basic control over your model aircraft and that you are not a danger to people or property.
A turn in the direction opposite to that introduced by the ailerons, caused by the drag of the down-going aileron exceeding the turning moment introduced by the up-going aileron.
A general term to describe a type of aircraft and/or a style of flying that incorporates any manoeuvre that would not be used by a full sized aircraft in normal flying.
The cross-section shape of a wing taken at right angles to the wing span., Also known as the wing section or rib section.
"After Run" is a special oil that should be used in your engine after you have finished flying for the day. It is specially designed to protect your expensive engine from rust and corrosion. It is essential you use "after run" when using fuel with a high "nitro" content as nitro causes corrosion. With the engine stopped open the carburettor of your engine and drop some (see bottle for recommended amount) after run down into the carb, and flick the engine over 6-10 times to ensure the after run covers the inside of the engine. See "caring for your engine"
Because the downward travel of the aileron causes more drag then the up travel, sometimes it is necessary to have a lower amount of travel in the downward direction compared to the upward direction. The differential can be set up either mechanically of electronically in a programmable computer transmitter. The extra drag of the downward moving aileron can in some aircraft cause a "yaw" effect making rolls look untidy, by reducing the downward travel you will get better looking more axial rolls from your aircraft.
Hinged control surfaces located on the trailing edge of the wing, one on each side, which provide control of the aircraft about the roll axis. The control direction is often confusing to first time modeller For a right roll or turn, the right hand aileron is moved upward and the left hand aileron downward, and vice versa for a left roll or turn.
Twin elevator servos plugged into separate channels used to control elevator with the option to also have the 2 elevator servos act as ailerons in conjunction with the primary ailerons.
An aerodynamic control which can be extended to increase drag and slow down an aircraft. Often used on model aircraft to control/increase descent rates. On some aircraft the air brakes are used in conjunction with the ailerons for lateral control at low speeds where the ailerons become ineffective.
The shape of the wing when looking at its profile. Usually either flat bottomed or symmetrical
The time spent actually flying your model aircraft.
Horizontal tail surfaces which do not have a separate elevator. The whole surface moves as one to give pitch control.
A device for measuring wind speed.
Angle of the wing chord line in relation to the longitudinal axis of the fuselage. This should not be confused with the "Angle of Attack".
The angle that the wing penetrates the air. As the angle of attack increases so does lift, up to a point (and drag) if the angle of attack is too high the plane stalls.
The ratio of the wingspan to the wing's chord (depth). For gliders this number will be larger than sport planes, which will generally be larger than a "jet" style aircraft.
An aircraft that flies by the lift generated by free wheeling rotating wings set "windmill" fashion above the fuselage. The forward motion of the autogiro provides the force to keep the rotors turning so unlike a helicopter an autogiro cannot hover.
Allows receiver to draw power from a main battery pack, eliminating the
need for (and weight of) a receiver battery.
To save the aircraft from loosing control and crashing, when at the end of
the flight the voltage of the battery falls to a set level the BEC cuts the
power to the motor but still supplies power to the receiver and servo's allowing
the aircraft to be brought in for a "dead stick" landing. This feature
is only found in ESC's (Electronic Speed Controllers) which are used to control
the speed of electric motors.
Connection using a ball, and a link which rotates on the ball. Used to connect the servo to a control surface or lever. These are more resistant to wear then a standard "clevice" and are "slop" free
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.
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.
Connection using a ball, and a link which rotates on the ball. Used to connect the servo to a control surface or lever.
A short rigid, aerial mounted to the model. Used to replace the longer standard receiver aerial.
A battery checker is a small electronic device that has a row of green, amber and red LED's on it. It is used to check the condition of the battery that is used to power the receiver and servo's. You need the read the manufactures instruction very carefully so you understand fully what it is indicating. It is best to fit a battery checker onboard and get used to checking it regularly. The reason why it is best to fit one on your aircraft as opposed to using an external one is that the voltage of the battery falls slightly when put under load (i.e. when the servo's are working) and this gives you a much better idea to the condition of the battery. A battery can read "OK" when the receiver is not switched on and no servo's connected, but can read "low" when every thing is connected, switched on and all servo's are moving, in this condition DON'T fly, recharge your receiver battery. I highly recommend that you fit an onboard battery checker on all your models., Is the destruction of your pride and joy and the loss of all that money not worth an extra tenner?
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.
What occurs when the friction at a joint is stronger than the linkage.
Having fun flying, without any pre-determined flight pattern.
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.
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 if the aircraft is too low or in a dangerous attitude by using the by using the "trainer switch" on his transmitter.
A very strong former within the fuselage used to mount the enging or electric motor
An elastic chord used to launch gliders. A number of different types of bungee are available with different characterisitcs.
Also known as crow. A mix which activates up flaperons and down innermost flaps for gliding speed control without spoilers or air brakes.
An instant type glue that is available in various viscosity's (Thin, Medium, Thick, and Gel). These glues are ideal for the assembly of wood aircraft and other materials. NOTE: Most CA glues will dissolve foam although new "Foam Safe Cyno" is available sometimes referred to as "Odourless Cyno" If you're not sure always test it on a scrap piece first. Commonly known as "Super Glue"
For modelling purposes, this is usually considered the point at which the aircraft balances fore to aft. This point is critical in regards to how the aircraft reacts in the air. A tail-heavy plane will be very snappy but generally very unstable and susceptible to more frequent stalls. If the aircraft 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 aircraft will have to come in faster to land safely. The CG should always be checked on every new model and only when the fuel tank is empty.
The spot where the lift of a wing (or wings) is said to centre.
The point on the upper surface of a wing. Relative to the chord. Where the lift can be said to centre.
The strut assembly at the centre section of a biplane or Parasol
monoplane.
The curvature of the wing or horizontal tail, from the leading edge to the trailing edge.
An aeroplane designed to fly with its tailplane in front of the wing, it also refers to a forward horizontal stabiliser. Some aircraft have canards in addition to a conventional horizontal stabiliser on the tail.
The part of the engine which controls the speed or throttle setting and lean/rich mixture via setting of the needle valve.
A nitrocellulose varnish like liquid used to shrink fabric onto a frame. Care should be taken to carefully read manufacturers instructions and work in an open environment as the fumes can become very overpowering.
The frequency number used by the transmitter to send signals to the receiver. If radios transmit on the same frequency, or channel, glitching will occur in the active receiver on that channel. This is due to conflicting signals sent by the two transmitters. Flying sites should have a frequency control system to ensure that only one radio operates on any given channel at one time. This is usually a board with some type of marker for each channel. If the marker is not available, someone else is using that channel. Do not use your radio unless you are sure you are the only one on the frequency. Click here for a full listing of 35Mhz channels used in the UK for model flying
The number of functions your radio can control. Eg: an 8 channel radio has 8 available servo slots used for separate control surfaces or switches. These channels can also be mixed on many radios.
The plug receptacle of the switch harness into which the charger is plugged to charge the "Receiver Pack". A "Battery Checker" can also be plugged into it to check battery voltage between flights. If you are not using an onboard battery checker (I highly recommend that you do fit a battery checker on all your models) It is advisable to mount the charge jack in an accessible area of the fuselage so a battery checker can be used without removing the wing.
Device used to recharge batteries and usually supplied with the radio if Ni-Cad batteries are included.
A stick used to "flip start" a model airplane engine and hence save your fingers from getting caught in the propeller when the engine starts or backfires.
The width of a wing or tailplane from front (leading edge) to back (trailing edge).
A small plastic or metal clip that is used to connect either a pushrod or closed loop connections to either the servoe arm or a control horn
A set up using two wires. One is pulled for one direction, the other is pulled for the other normally used on the rudder of aircraft and provides positive control.
A fuel tank where the fuel pickup (the "clunk") is at the end of a flexible tube. Gravity ensures that the clunk is always at the bottom, enabling fuel to be collected whatever the orientation of the fuel tank.
Usually refers to a type of structure made with layers of fiberglass or fiberglass-like materials such as carbon fibre. The materials are called composites.
Two propellors on the same axis rotating in opposite directions. It is a convenient method to increase power for a given propellor diameter.
An arm fastened to a control surface to which is connected the control rod.
Parts of an aircraft that are activated by the pilot or servos (in the case of a radio-controlled model) to change the airflow around the surfaces of the aircraft. The changes in airflow cause the aircraft to roll, pitch, or yaw.
Is a 360° turn without using the ailerons just rudder. Control line aircraft go round in circles with their wings horizontal or flat, they dont bank.
In a conventional servo, the motor has a steel core armature wrapped in wire that spins inside the magnets. In a coreless design, the armature uses a thin wire mesh that forms a cup that spins around the outside of the magnet eliminating the heavy steel core. A coreless motor does not have magnets as standard servo motors do, so they have a smoother, more constant, and stronger action. Regular servo motors have either 3 or 5 magnets (poles) which when the armature is between these, the servo motor is at its weakest.
A specially shaped nose to enclose an engine.
Also known as butterfly. A mix which activates up flaperons and down innermost flaps for gliding speed control without spoilers or air brakes.
A component used to determine the operating frequency of a Radio Transmitter or Receiver. The frequency or Channel of R/C equipment can be changed by plugging in the appropriate crystals.
An instant type glue that is available in various viscosity's (Thin, Medium, Thick, and Gel). These glues are ideal for the assembly of wood aircraft and other materials. NOTE: Most CA glues will dissolve foam although new "Foam Safe Cyno" is available sometimes referred to as "Odourless Cyno" If you're not sure always test it on a scrap piece first
High-end convenience feature which allows control/adjustment of servo function without sending signal through receiver. Requires optional DSC cord.
A reference line or point from which measurements are taken.
A term used to describe unpowered flight (glide) when the engine stops.
Markings come in many different forms and are normally provided with the kit.
An aircraft with a wing of a triangular planform, the base of the triangle forms the trailing edge.
This type of charger will eliminate the guesswork. When the battery is full it "peak", this type of charger detects this "peak" and then switches to a trickle charge, which will not damage the battery pack.
Slang term for the condition in which the model is set up to fly smoothly and predictably. This is the state where the mechanics and electronics work together to produce the best performance.
Diesel engines can offer a lot in terms of power to weight ratio and the ability to turn a large propeller.
Because the downward travel of the aileron causes more drag then the up travel, sometimes it is necessary to have a lower amount of travel in the downward direction compared to the upward direction, the differential can be set up either mechanically of electronically in a programmable computer transmitter. The extra drag of the downward moving aileron can in some aircraft cause a "yaw" effect making rolls look untidy, by reducing the downward travel you will get better looking more axial rolls from your aircraft.
The upward "V" angle of the wings when viewed from the front expressed in degrees i.e. 4°
An electronic component which only allows current to flow one direction. Protects a transmitter against reverse polarity or power surges during charging.
A wheeled frame that a model sits on to effect a take-off. The dolly either remains on the ground or drops off almost immediately.
The slight tilting down of the engine or propeller thrust line to exert a slight downward pull under power.
In the circuit flying parallel with the runway in the opposite direction to take-off, i.e. going in the same direction as the wind.
A type of receiver that converts the incoming frequency through two intermediate stages. It allows the receiver to be much more sensitive only to the channel it is using and blocks out external frequencies. This is what helps the receiver to be very narrow-band, in other word it's a good feature.
A switch on the transmitter that can bet set so that the ailerons, elevator and/or rudder can have reduced movement making the aircraft less sensitive. Lower movements/rates are better for learners, who tend to over control.
A small diameter multi-bladed fan, operated at high rpm inside a tube or duct. The ejected air provides thrust in the same way as a jet engine. The fan can be powered by an glow engine or an electric motor.
ESC's are only used in aircraft which are powered by electric motors and are used to control the speed of electric motor(s).
Hinged control surface located at the trailing edge of the horizontal stabiliser, which makes the aircraft climb or dive. Pulling the transmitter elevator control stick back, toward the bottom of the transmitter, makes the elevator move in an upwards direction, which causes the aircraft to climb, and vice versa to dive.
An elevator split into 2 halves which can be operated independently so that the same control surfaces can be used to control the roll of an aircraft as well as the pitch. Often seen on Flying Wings and Delta planform models.
Used to apply flaps along with elevators to increase lift, allowing aircraft to fly at slower speeds, make tighter loops or turns, etc.
A two part glue that is extremely strong. It is generally available in 5 minute, 30 minute and 1 hour formulas. The longer it takes to set the stronger it is (i.e. 1 hour is stronger the 5 minute) Used for critical places in the aircraft where high strength is necessary.
Offers servo travel that is not directly proportional to stick travel. Control response is milder below half-stick, but becomes increasing stronger as stick travel approaches 100%. Great for aerobatics and trouble situations. Makes highly aerobatic aircraft smother to fly around stick centres
Frequency Modulation. This describes the mode of transmission of radio signal from transmitter to receiver. 35 Mhz radios use FM modulation.
A safety feature which sets servos to a pre-set position if the signal is lost or interrupted. Additionally, battery fail-safe is a safety feature which brings the throttle servo down to idle as a warning that the receiver battery's voltage is getting dangerously low. This feature is generally only available on "high-end" radios and the manufactures instructions should be read thoroughly and understood before using as incorrect set up could be dangerous.
A streamlined cover over a joint or around angular parts of an aircraft intended to reduce drag.
A box used to hold and transport all equipment used at the flying field, electric starter, battery, tools, etc.
A rounded contour used at the junction of vertical and horizontal surfaces on an aeroplane, to reduce air resistance.
A fast battery charger designed to work from a 12-volt power source, such as a car battery, and used to charge the Ni-Cad's for either your transmitter or receiver.
The non-moving surface that is perpendicular to the horizontal stabiliser and provides yaw stability. This is the surface to which the rudder attaches.
The last phase of a flight when lined up with the runway during the landing approach.
A strong bulkhead immediately behind the engine on a powered aeroplane.
The movement of two aileron servos, both in the same direction at the same time, acting as flaps. If mixed with elevators gives very tight loops.
Hinged control surface located at the trailing edge of the wing inboard of the ailerons (near the fuselage). The flaps are lowered to produce more lift from the wing, allowing a slower take off and landing. Flaps are often found on scale models, but not on trainers.
The point during the landing approach in which the pilot gives an increased amount of up elevator to smooth the touchdown of the airplane. Ground effect may result in the aircraft remaining airborne for longer than expected.
Is a 360° turn without using the ailerons just rudder. Control line aircraft go round in circles with their wings horizontal or flat, they dont bank.
A box used to hold and transport all equipment used at the flying field, electric starter, battery, tools, etc.
The battery that is used to power the receiver, and servos. The flight pack is generally of the rechargeable Ni-Cad or Ni-Mh
A phenomenon whereby the elevator or aileron control surface begins to oscillate violently in flight. This can sometimes cause the surface to break away from the aircraft causing a crash. There are many reasons for this, but the most common is excessive hinge gap or excessive "slop" in the push-rod connections and control horns. If you ever hear a low-pitched buzzing sound, reduce throttle and land immediately.
An aeroplane with a fuselage shaped like a boat. For operation off water.
This is a general term which groups together all the moving or working surfaces i.e. Ailerons. Elevators Flaps (if fitted) and Rudder.
A very strong former within the fuselage used to mount the enging or electric motor.
The tips of the wing are forward of the leading edge at the root of the wing. There are many problems with this design, one being torsional stability resulting in flutter. The advantage is an almost unstallable aircraft.
This is generally referred to as the system that is used at the flying field so that a transmitter on the same frequency is not turned on as an aircraft that is preparing to fly or is actually flying. There are several types, so find out what system is used and follow it faithfully as you don't want to be "shot down" or to shoot a fellow flyer down.
"Fun Fly" refers to a type of model aircraft that has been specially designed for very slow 3D type of manoeuvres, generally not very pretty, but good "fun to fly" They have short, stubby but thick wings. They are built very light and have very large moving surfaces with lots of movement, good for "prop hanging".
The body of an aircraft that has the wing, horizontal stabiliser and fin attached to it.
Although practical model jet engines have been around since the early 1980's it has only been in the past few years that home construction has become viable. Careful design has made simple home construction possible using basic tools and a small centre lathe. Purchased items can feature self starting and automatic shutdown. They generally run on "Jet A1" (same fuel as Jumbo jets use!) or domestic Parafin.
A term given to a 12V DC sealed lead acid rechargeable battery that is commonly used to power either your electric starter or flight/field box.
A latticework or basket-weave construction, a good example of this is the rear fuselage construction of the Welligton WWII brithish bomber.
A momentary loss of signal by the receiver making the model twitch, this generally only happens when the model is low and far away. Glitches can also be caused by interference generated on the aircraft. When two metals touch a small amount of electrically generated noise sometimes referred to as RFI is produced, and this can affect the performance of the receiver. Never use metal clevices on engines that have metal throttle arms for this reason.
The heat source for igniting the fuel/air mixture in the engine. When starting the engine a battery is used to heat the filament. After the engine is running, the battery can be removed. The wire filament inside the plug is kept hot by the "explosions" in the engine's cylinder. See next heading and "Idle Bar" plug.
A rapid circular rotation of a model on the ground, usually performed while taxying or during take off. Taildragger aircraft are particulalrly suceptible to this as they are sensitive to crosswinds.
Small strengtheners fixed at points of heavy stress in an aircraft’s structure, normally triangular in shape.
A gyro is an electromechanical, or electronic device which aids in the control of an R/C model. The gyro senses motion in one axis, and directs the servo to counter that motion. The sensor, which can be a mechanical gyroscope, or an electronic piezo crystal, detects unwanted movement. The gyro then instructs the servo to counter for that motion. At all times, the radio commands will override the gyro command. The level of control the gyro had is adjusted by the GAIN setting. Mechanical Gyro: uses a mechanical gyroscope (similar to the child's toy) to sense movement. Piezo Gyro: uses a piezo crystal to sense movement.
This describes a type of Gyro which senses rotation, and maintains direction. This is accomplished by sensing the rate of motion, and the time of motion, then compensating for the distance. While this sounds complicated, the effect is that if you have the model dialed in, and point the nose north, with a heading hold gyro on the yaw axis the model will continue to face north until you command it to yaw. See also Heading Lock. This is not recommended for aircraft use while in flight due to the requirement to use YAW (rudder) command to turn the model. Often used for ground use only for perfect take off and landing runs.
Slang term for Heading Hold Gyro.
The horizontal tail surface at the back of the fuselage which provides pitch stability to the aircraft.
A General term for glow, diesel or petrol burning engines
This is a setting on the transmitter which limits the throttle minimum. Particularly useful for 3D style of flying.
The angle, relative to the fuselage datum, at which a wing is set.
Resistance of a wing to forward movement due to disturbance of the surrounding air and related to the lift produced by the wing.
Flying up-side-down
A very light paper, usually made from rice straw, used for covering some free-flight aircraft.
Although practical model jet engines have been around since the early 1980's it has only been in the past few years that home construction has become viable. Careful design has made simple home construction possible using basic tools and a small centre lathe. Purchased items can feature self starting and automatic shutdown. They generally run on "Jet A1" (same fuel as Jumbo jets use!) or domestic Parafin.
A fixture or form for holding parts together for assembly. A jig is normally used where a series of parts need to be assembled in the same way a number of times. However, when constructing a fuselage a jig may be used to ensure alignment from front (engine mounting position) to rear (tail surfaces mounting position).
Accelerates the curing of all "Cyno" glues, helps with gap filling and hard-to-bond- surfaces - Smells awfull!
This is where the flow over the top and under the wing meet at the trailing edge with no abrupt change in direction.
This is checked to make sure that the left hand side of the aeroplane is the same weight as the right hand side when viewed from the top. A rough check of the lateral balance can be carried out by holding the tip of one blade of the propellor (when it's pointing vertically) and the top of the fin. Add lead to either side to get the model to balance.
A wing designed such that the air flow over it is laminar at zero to small angles of attack. In Laminar flow the adjacent layers of air flowing over the wing do not mix.
The axis extending through the centre of gravity of an aircraft and parallel to the wing surfaces.
Ailerons give lateral control allowing the aircraft to be rotated around its lateral axis.
The front edge of the wing or stabiliser.
The sum of all the aerodynamic forces acting on an aircraft at right angles to the flight path. When the aircraft is in steady level flight the lift is equal and opposite to the weight of the aircraft. Wings create lift.
An aircraft that uses the shape of its body to generate lift instead of using wings.
An aerobatic manoeuvre which combines extreme roll pitch and yaw changes to produce a violent movement of the aircraft. The name is derived from a Polish word which describes the effect of too much liqueur spirit.
The main fore-and-aft strips in a fuselage.
An aircraft with a single set of wings mounted at or near the bottom of the fuselage.
The unit of radio frequency. i.e. 35Mhz means that the signal oscillates 35 million times per second, in other word the signal rises and falls 35,000,000 times every second - That's a lot!
A cellulose lacquer solution poured onto the surface of a tank of water to form an extremely thin film used for the covering of F1D and other types of free-flight indoor aircraft.
Allows a single input to control the operation of two or more servos. Simplifies routine flying and allows more involved manoeuvres, great for intermediate and advanced fliers. For example, Flap-to-elevator mixing: Most models will change pitch upon deploying flaps (some will climb; others dive). After test flying the model and determining the direction and amount of elevator throw required to correct for this change, a pilot may set a flap-to-elevator mix to compensate. Once the mix is operating properly, when the modeller gives flap control, the radio automatically also gives the proportional amount of elevator throw, keeping the model flat and straight.
A specialised lever which has three or more pivots. The length between pivots will determine the proportion of the mix between two or more linkages.
A removable unit is used in most computer radios, containing all frequency control equipment, including the crystal and all tuned components.
The distance between the point at which a force is applied and the point of action of the force. For example, the distance between the Centre of Gravity and nose, or Centre of Gravity and tail.
A form of fuselage construction with rounded exterior and very little internal structure in which the skin carries virtually all stresses.
An aircraft with only one wing.
This is a general term which groups together all the moving or working surfaces i.e. Ailerons. Elevators Flaps (if fitted) and Rudder.
American word for exhaust.
A radio with a 20 Khz band width. All Futaba radios produced 1992 or later and all Futaba FM and PCM radios ever produced are narrow band.
The part of the engine which is used to control the mixture at the "Top End" to achieve maximum revs.
Rechargeable batteries which are typically used to power transmitters and receivers. If not properly cycled regularly they develop a "memory" and think they have a smaller capacity then they actually have. A battery with a short memory can be returned to it's normal state by several discharge/charge cycles. Ni-cad can be charged up to 600 times, but this is dependant upon many variables like charge current, discharge current, temperature etc.
Rechargeable batteries which can used to power receivers. Unlike Ni-Cad batteries they do not develop a "memory". For the same electrical storage capacity normally expressed in mAh (milli Amp/Hour) a Ni-Mh battery is smaller and lighter. With every good side there is always a bad side (Luke Skywalker/Darth Vader), Ni-Mh batteries cost more, can not deliver high current compared to Ni-Cad's, can be tricky to charge and must be used immediately after charging.
A fuel additive which makes a model engine idle smother and more reliably as well as providing more power at maximum revs. It is actually less combustible than Methanol. Methanol makes up the largest percentage of model fuel. So why does nitro give more power? Well the addition of Nitromethane allows more fuel into the combustion chamber of the engine, which gives a bigger "bang" which in turn gives more power. The down side is that the engine has to run on a richer fuel/air setting which means you tank of fuel won't last as long. Another down side is that the more nitro a fuel contains the more it costs. It is also thought to be corrosive to the internal parts of an engine making the use of "after run" essential. Ideal nitro content varies from engine to engine. Refer to the engine manufacturer's instructions for best results. Nitro content in fuel is indicated by the percent of the fuel, i.e."5%" indicates 5% Nitromethane per volume.
A nose over is when due to long grass, binding wheels or just the characteristics of the model (e.g. WWI models and Spitfires are well known for this) the aircraft comes to rest on it's nose or even flips onto it's back during take off or landing.
The supporting structure at the the very front of the aircraft to support the front of the engine, normally used with big four stroke engines.
A shock absorbing system used in undercarriages.
An aeroplane that flies by flapping its wings like a bird.
PCM systems use digitally encoded signals to minimise interference and provide
today's most advanced RC control. This feature can be dangerous if not set
up correctly, please see the BMFA
Warning about PCM fail safes.
Pulse Position Modulation. Another term for "FM".
Described at first as the "Guardian Angel". On 19th August 1913 Pegoud was the first person to descend on a parachute in Europe.
An aeroplane in which the wing is mounted above the fuselage on struts.
A particular style of aircraft that has been specially designed to fly a set type of aerobatics. These type of aircraft generally are of the 60 size and larger. Competition aircraft normally are around 2 meter wing span, have deep fuselages and 1.40, 4 stroke engines, needless to say they are at the more expensive end of the hobby but are a dream to fly.
A style of flying encouraging large, very precise and smooth manoeuvres.
The point at which a battery will no longer accept a charge, and converts the energy to heat. This is damaging to the battery pack, and potentially hazardous. It is recommended to use a "Delta Peak Charger" when charging any Ni-Cad batteries
This type of charger will eliminate the guesswork. When the battery is full it "peak", this type of charger detects this "peak" and then switches to a trickle charge, which will not damage the battery pack.
The aircraft's up/down attitude is controlled by the elevator and is referred to as the pitch. Pitch is illustrated by holding the aircraft at each wing tip. Raising or lowering the nose is the pitch movement. This is how the climb or dive is controlled.
Sheet-wood covering accomplished by glueing thin flat wood strips side by side on a fuselage.
Sheet wood made by glueing together two or more very thin layers of wood with the grain of adjacent layers at right angles.
A form of dihedral in which there are one or more changes of dihedral in each wing panel.
12-volt distribution panel that provides correct voltage for accessories like glow-plug clips, fuel pumps and electric starters. Usually mounted in a field/flight box and connected to a 12-volt "Gel Cell" battery.
A pre-flight check should be carried out every time you visit the field, it includes amongst other things a "radio check", making sure the engine, propellor, spinner, wheels (if fitted) and flying surfaces are all secure. Flying surfaces must also be checked to make sure they are moving in the right direction. If you are not sure how to perform all these checks, ask a fellow flyer, I'm sure they will be willing to help.
An assembly of radially disposed blades with an airfoil shape that when rotated in air produce thrust.
An assembly of radially disposed blades with an airfoil shape that when rotated in air produce thrust.
Props are designated by these two numbers, for instance 10 - 6 (often pronounced 10 by 6). The first number is the prop's length, 10". The second number is the pitch or angle of the blades. The 6 represents the distance the propeller will move forward in one revolution, in this case 6".
A set up using two wires. One is pulled for one direction, the other is pulled for the other normally used on the rudder of aircraft and provides a more positive movement.
A plane in which the engine is mounted ahead of the propeller, so that the propeller pushes instead of pulls.
A water based type of adhesive.
Abrievation for "Radio Controlled"
An engine design where the cylinders are designed symmetrically around a central crankshaft and hence radiate out.
A moulded plastic or metal mount which is fastened to the mounting lugs of an engine and then bolted directly to the engine bulkhead or firewall.
A type of jet engine with very few moving parts which consists of a specially shaped tube open at both ends in which air is compressed purley from the forward speed. The addition of fuel and this being then ignited increases the volume of air. Note that ramjets only operate above certain speeds.
A measure of the speed with which an airplane rotate around its long axis, or roll. This is normally measured in degrees per second.
A switch on the transmitter which changes the amount of movement of a control surface when the stick is moved.
A tool for making holes bigger.
The radio unit in the aircraft which receives the transmitter signal and tells the servos which direction, what speed and where they should stop.
A reversal of the camber on a flying surface. Often used on flying wing or delta planform aircraft.
This is the vibration frequency of a rotating or moving object. When the resonance of many parts of a machine are in synch, the whole machine will vibrate at a greater rate. This can cause vibration damage. Resonance can cause difficulties in an aircraft, particularly when using a anti-vibration mount with an improperly balanced propeller/spinner where the engine is vibrating at one frequency and the propeller at another. Vibration can also cause the airframe to resonate causing at best extra noise and at worst failure in the airframe causing a crash.
When the undercarriage folds up into the wing, normally only used on scale aircraft and "pattern" aircraft which can be operated either mechanically via a special "retract servo" or pneumatically via a valve which is operated via a standard servo
Slang for retractable undercarriage.
Specifically used for mechanical retracts. It is a powerful non-proportional servo which only moves 180 degrees. That is to say this servo is either "off" (gear up and fully locked) or "on" (gear down and fully locked). No ATV, EPA, or AST adjustments can be made on these servos because they are not proportional. The linkage must be set up properly to allow this servo to operate at its full range and do its job.
The cross-section shape of a wing, from leading to trailing edge.
The aircraft axis controlled by the ailerons. Roll is illustrated by holding the aircraft by the nose and tail. Dropping either wing tip is the roll movement. This is used to bank or turn the aircraft. Many aircraft are not equipped with ailerons and the Roll and Yaw motions are controlled by the rudder. This is one reason why most trainer aircraft have a larger amount of dihedral.
The part of a wing where it meets the fuselage.
An air cooled engine whose cylinders, arranged like the spokes of a wheel, rotate around a fixed crankshaft. The fuel is supplied to the engine through the crankshaft and the engine normally exhausts straight out the top of the cylinder. This arrangement was used with early engines as the mass of the engine was used as the flywheel allowing the engine to run smoothly.
Hinged control surface located at the trailing edge of the vertical stabiliser, which provides control of the aircraft about the Yaw axis and causes the aircraft to Yaw left or right. Left rudder movement causes the aircraft to Yaw left, and right rudder movement causes it to Yaw right.
Mix used to counteract undesirable roll which often happens with rudder input, especially in knife edge, also called roll coupling.
Abbreviation for receiver.
Ultra light, solid-state components which offer greater vibration resistance and reliability.
American word for a glider
The electromechanical device which moves the control surfaces or throttle of the aircraft according to commands from the receiver. It's the device which does the physical work inside the aircraft.
Reverses the rotation of a servo with the flip of a switch. Adds ease and flexibility during installation.
The removable arm or wheel which bolts to the output shaft of a servo and connects to the push-rod. Careful positioning of the holes in the output arms will allow you to produce a mechanical differential effect for airlerons or even throttle control where more precision is required around the idle setting.
This radio feature allows you to install the servos where they can give the best pushrod routing without concern about the direction of servo rotation. When your installation is complete, turn on your radio and check each channel. If a channel operates opposite of its intended direction, a simple flick of a switch corrects the problem.
The direction of flight is at an angle to the fore aft axis of the aircraft.
Offsetting the propeller thrust line, so there is a slight sideways pull. Side thrust is used to counteract the effects of the torque of the engine. The courser the pitch of the propellor used, the more side thrust is needed.
A device used to reduce noise from the exhaust side of an engine.
The reason for a crash due to another person turning on a transmitter on the same frequency as a flying aircraft causing loss of control of the flying aircraft and subsequently the inevitable crash.
Slats are used on the leading edge of a wing to improve lift. They help the formation of a smooth boundary layer over the leading edge allowing the wing to operate at a higher angle of attack before seperation occurs.
The column of air pushed rearward by a rotating propeller; it always moves faster than the aeroplane itself.
Unwanted, excessive movement in a control system. Often caused by a hole in a servo arm or control horn that is too big for the push-rod wire or clevis pin. This condition allows the control surface to move without transmitter stick movement. Also, see flutter.
No, not a legless reptile but a flexible pushrod consisting of a plastic or braided metal wire inner, inside a plastic sleeve.
Combines rudder, elevator and aileron movement to cause the aircraft to snap or spin on the flip of a switch.
A plastic film that is used to cover models, it has a heat sensitive glue on the back which sticks to the balsa wood. It also shrinks when heat is applied giving that bright shiny drum like finish. It is fuel proof against glow fuel but not petrol or diesel
A very thin plastic film that is used to put markings and patterns on models, it has a sticky back. It also shrinks when heat is applied. It is fuel proof against glow fuel but not petrol or diesel
Your first totally unassisted take off, flight and a controlled landing.
Spanwise load-carrying members of a wing or tail.
The rapid rotation of an aircraft after it has stalled. In order to recover the aircraft it is necessary to first increase the airspeed so that the flying surfaces are no longer stalled.
An ever-tightening downward corkscrew flying path.
The characteristic of an aeroplane that permits high-speed banked turns without diving to the ground.
The nose cone which covers the hub of the propeller. Check that the spinner does not touch the propeller blades as this may result in the propeller blades wearing and possibly failing. Remember a large spinner will result in less effective propeller area and a reduction in engine cooling.
Controls which can be deployed into the airflow to "spoil" the lift. Usually found on gliders and used to aid landing.
A surface that is used to stabilise the aircraft during normal flight e.g. the tail fin and tailplane. Other designs such as a V-tail may be used to provide both pitch and yaw stability.
The tendency of an aeroplane to return to level flight, after having been disturbed by an upsetting force.
What happens when the angle of attack is too great to generate lift regardless of airspeed. (Every airfoil has an angle of attack at which it generates maximum lift, the airfoil and aircraft will stall beyond this angle). A stall can be recognised by a sudden uncontrolled drop of a wing at slow flying speed, this drop of a wing is often followed by a spin if not caught quickly.
The time spent actually flying your model aircraft.
Short Take Off and Landing. Describes an aircraft with special high-lift devices to keep the take off or landing run as short as possible.
Light, lengthwise fuselage strips intended more to give the desired shape than to add strength.
Ailerons consisting of simple strips along the full length of the wing trailing edge.
This is a trim function on many computer radios, allowing minor trims inputs to be stored electronically in the transmitter so when a different model is selected from the transmitter's memory this model will fly true when the trims are set to their centre position.
The leading and trailing edges of a wing are angled backwards to reduce drag at high speeds.
Is the name given to the small electrical switch and wires that is installed in the aircraft to turn the receiver on and off.
Arrangement where the tailplane is mounted on top of the fin.
A small adjustable surface on wing or tail surfaces, used to make small trim changes.
An optical sensor designed specifically to count the speed of a turning propeller and display it as RPM (Revs Per Minute)
An aircraft which has an undercarriage arrangement where the mainwheels are under the wing with smaller wheel at the tail end of the fuselage. The aircraft sits on the ground with a nose-high attitude.
A mixture of elevators and ailerons. On a delta wing the elevators and ailerons are mixed and known as elevons. However, as well as normal ailerons the tailplane horizontal surfaces may be mixed to form elevators and ailerons and hence enhancing the normal roll control provided by the ailerons.
A fixed angular fixture use to support the tail end of an aircraft on the ground instead of a wheel.
An airplane with wings of similar size mounted one in front of the other, on pretty much the same level.
A stiff pattern for marking the outlines of pieces to be cut from sheet wood or metal.
A rising column of relatively warm air.
With a tail dragger there is an art in landing with all three wheels touching the ground at the same time.
The programming function of the radio which allows throttle operation to be adjusted to meet the modeller's specific needs at various points along the throttle movement. Particularly useful with 2-stroke engines in providing linear throttle response at the various points of throttle application.
The propulsive force developed by a driven propeller or jet engine
An imaginary line drawn along the propeller shaft and extending rearward through the aeroplane.
The outboard end of one wing stops developing lift, causing the plane to roll suddenly in the direction of the stalled wing. This situation is not fun when you are only a few feet off the runway trying to land.
Rudder used when an aircraft is flying on its side (knife edge) to keep the flight path horizontal.
The force which causes rotation. When viewed from the front a propellor rotates in an anticlockwise rotation, the airframe then wants to turn in a clockwise direction.
An aerobatic manoeuvre that uses the torque reaction to accelerate the rate of roll of an aircraft.
Landing and taking off without a pause. Useful to practise when learning to fly.
The rearmost edge of the wing or stabiliser.
A model designed to be inherently stable and fly at low speeds, to give first-time flyers time to think and react as they learn to fly.
This is the unit that you hold that sends radio waves to the receiver the aircraft which in turn tell s the servos what to do which gives control of the aircraft.
When model takes off for the first time, there is no way of knowing exactly
what's going to happen, some models will climb, while others may want to dive,
some will try to turn left, others right. Some models will be doing both at
the same time on the first flight.
It doesn't mean that there is anything wrong with the model, but these minor
differences must be "trimmed out" for the model to fly straight
and level. That's why a new model's first flight is best done by an experienced
model pilot. Someone whose reflexes are already conditioned to anticipate
the model's actions and instantly make the right move to counteract it and
save your new pride and joy.
An undercarriage arrangement where the main wheels are set under the wing just behind the center of gravity point, with the third wheel positioned under the nose just behind the engine. The aircraft sits on the ground with the fuselage level.
The two stroke engine has been the main stay of powered model aircraft for a number of years due to the high power to weight ratio. The main downfall of the two-stroke engine is the high fuel consumption. The basic construction, operation and general notes on starting, running and maintaining are all included within this section.
Abbreviation for transmitter.
Ultra High Frequency.
The concave curve on the underside of some aerofoils.
The wheel and strut assembly that supports an aeroplane at rest on the ground and during take-off and landing.
Used on a V-tail model to have two servos operate two control surfaces that act as both rudder and elevator.
A tube reduced in diameter at its centre. Air flowing through it is speeded up by the change in shape.
The non-moving surface that is perpendicular to the horizontal stabiliser and provides yaw stability. This is the surface to which the rudder attaches.
Very High Frequency.
Air from the high pressure region under the wing flows to the low pressure region above the wing when generating lift, the result are vortices. This reduces the effective lifting area of the wing and generates drag. If the wing span was very very long the loss due to this flow from bottom to top would be very low and the induced drag very low. This is why high aspect ratio wings are used where low drag and high lift is required e.g. gliders.
Twist incorporated in wing tips to raise the leading edge, to give more incidence at the tip than at the root. Generally not a desirable condition as it makes aircraft tip stall easily.
An intentional twist in the wing, causing the wing tips to have a lower angle of attack than the wing root. In other words, the trailing edge is higher than the leading edge at the wing tips. Washout helps prevent tip stalls.
American version of "Wheel Spats"
Designed to reduce the drag of fixed undercarriages by providing an aerodynamic shroud over the top section of the wheels.
The main lifting surface of an aircraft.
Expression for the weight per unit wing area of a model. Thermal gliders might have a wing loading of around 10 or 12 ounces per square foot. Large scale power models may be over 24 ounces per square foot.
The chord-wise cross section of a wing. Since the first days of flight wing sections have been continually changing and optimised for different aspects: lift, drag, low speed, high speed, strength.....
The distance from wing tip to wing tip
The earliest form of roll control was produced by warping the whole wing. Raising the trailing edge of the right hand wing and lowering the trailing edge of the left hand wing will result in the aircraft rolling to the right.
This is a general term which groups together all the moving or working surfaces i.e. Ailerons. Elevators Flaps (if fitted) and Rudder
The rudder on an aircraft controls yaw,moving the rudder left or right causes the nose to move to the left or right, this movement is referred to as "yaw".
A simple Z-shaped bend in the wire end of a pushrod, which is used to attach the pushrod to a servo output arm. When using a z-bend to link to the throttle arm on the engine carburettor care should be taken to avoid metal to metal links as these can result in radio interference.
An inexpensive plier type tool used for easily making perfect Z-bends.