Airframes, Engines and Systems Flashcards
Airspeed Indicator
Instruments tells the pilot at wich speed the aircraft is flying through the air
Attitude Indicator
Also called the Artificial Horizon, this
gyroscopic instrument tells the pilot if the
aircraft is in a nose high or nose low attitude, and or if the aircraft is banked to the left or to the right.
Altimeter
The Altimeter indicates at what height the
aircraft is compared to sea level.
Vertical Speed Indicator
his instrument tells the pilot if the aircraft is
climbing or descending, and if so, at what
speed in feet per minute.
Heading Indicator
This gyroscopic instrument is used like a
compass, but it is more precise and more
stable during climbs, descents and turns.
Turn Coordinator
In a turn this gyroscopic instrument gives the
pilot an indication of the rate of turn, how
long it will take to turn 180°.
It also includes the ball, that shows whether
or not the flight is coordinated (symmetrical).
Tachometer
This instrument allows the pilot to precisely
set the engine RPM.
VOR
The VHF Omnidirectional Range is a radio
navigation instrument.
● Its Course Deviation Indicator (CDI) gives
the pilot an indication on the position of the
aircraft in relation to a ground station.
● The VOR is the primary system used to
define airways.
ILS
The Instrument Landing System is a very
sensitive VOR that also includes vertical, glide
slope information.
● It is used for precision approaches when
landing in poor weather conditions.
ADF
● The needle of the Automatic Direction Finder always points towards the ground station on which frequency the receiver is operating, acting like an “artificial North pole”.
● This radio-navigation instrument is also
called a radio-compass.
GPS / GNSS
● Global Positioning System / Global Navigation Satellite System
● Uses a satellite constellation and a database to pinpoint the
airplane’s position anywhere in the world.
Transponder
● Whenever it is interrogated by a RADAR the Transponder
sends back a 4 digit code, along with altitude information if operating in Mode C.
● This allows Air Traffic Controllers to identify the aircraft displayed as echoes on their RADAR screens.
Three types of airframes?
- Truss
- Semi-Monocoque or Stressed Skin
- Composite
What is a Truss?
● A fuselage that is usually made up of
steel or aluminum tubes, which are
welded or bolted together in the shape
of a truss design.
● The strength of this design comes from
the steel truss tubes.
● The truss may be covered with metal,
fabric or composite materials for
aerodynamic purposes.
What is a Semi-Monocoque?
● This airframe consists of a series of formers (or bulkheads) held together by stringers running lengthwise.
● The frame is wrapped tightly with a skin that is called Stressed Skin.
● It is called stressed skin because the airframe loads pass through
the aircraft skin, unlike in a truss design, where the loads travel through the internal frame of the aircraft.
● The majority of aircraft manufactured today are of this type of airframe.
What is a Monocoque?
● If the stringers are eliminated, then we would have a Monocoque type of airframe.
● Like Semi-Monocoque, it also employs Stressed Skin.
What is Composite pros?
● This is one of the newer types of construction and is frequently used in homebuilt aircraft and some new designs such as Cirrus, and Diamond Aircraft.
● Allows for smooth, compounded curved
construction.
● It makes use of materials such as Fiberglass, Carbon Fiber, or Kevlar.
● Composites are stronger and somewhat lighter than metal and do not have fatiguing problems like metal.
What is Composite cons?
● Cons
➢ Composites have their own set of problems such as heat deterioration and internal damage from impact that does not show externally.
➢ More expensive than aluminum.
➢ Also, metal structures will permanently deform before they break, giving warning of overstress, whereas composite structures generally will not give warning of overstress and will break suddenly.
What are the two main types of landing gear configuration?
➢ Tricycle － These aircraft have a nose wheel.
➢ Conventional － These aircraft have a tail wheel and are often called taildraggers.
● Either one of these configurations can be fixed or retractable.
Advantages of the Tricycle Gear?
● Advantages over Conventional gear:
➢ Does not nose over as easily.
➢ Better directional stability on the ground.
➢ Visibility over the nose while taxiing is better.
➢ Overall ground handling is easier.
Advantages of the Conventional Gear?
● Advantages over tricycle:
➢ Propeller clearance is increased.
➢ Landing gear experiences less parasite drag.
➢ Better suited for rough and unimproved runways as the main gear takes most of the load.
➢ Less damage to the plane if the wheel gives out!
Retractable Gear
● Gear that either folds or tucks away into the wings or fuselage.
● Retractable gear results in a huge reduction in parasite drag and noise by making the aircraft more streamlined.
● Several methods are used to retract the gear: electric motor, hydraulic pump, or manually operated.
➢ If an electric motor or hydraulic pump is used a manual backup for gear extension is also available for in an emergency.
● Disadvantages
➢ More complicated to maintain
➢ You can forget that it is up!
3 types of Main Gear?
● Split axle
● Spring steel cantilever
● Single Strut
What type of brakes do we have?
● Most aircraft are fitted with hydraulic disc brakes similar to those found on automobiles, however, unlike an automobile there is a right and left brake system.
➢ This is known as differential braking.
Pros of the Differential braking?
● Having brakes that operate in this manner allows the pilot
greater control and a much tighter turning radius on the ground.
What are flaps?
● Flaps are devices installed on the wing to increase the lift and drag of the wing by increasing the camber of the wing and some types wing area.
5 types of flaps?
➢ Plain flap
➢ Split flap
➢ Slotted flap
➢ Fowler flap
➢ Combo flaps
Particularity of soft or rough airstrips for the tire?
low pressure tires
What are flaperons?
● A flaperon is a type of aircraft control surface that combines aspects of both flaps and ailerons.
● In addition to controlling the roll or bank of an aircraft, as do conventional ailerons, both flaperons can be lowered together to
function similarly to a dedicated set of flaps.
What are cowl flaps?
● On high performance piston engine
powered aeroplanes adjustable openings
called cowl flaps are incorporated into the
cowling to control the amount of cooling
air circulating around the engine.
● During high power settings, such as
during takeoff and climb, the forward
airspeed of the aeroplane is low and
engine power is high.
Horizontally Opposed Engine
● These are the most common type of reciprocating, air-cooled four-stroke, piston engines used in general aviation aircraft.
● Use even number of cylinders and has a small frontal area giving low parasite drag.
What are the keys part of the piston engine?
- Cylinder
- Intake valve
- Exhaust valve
- Piston
- Spark plug
- Crankcase
- Connecting rod
- Crankshaft
Radial Engines
● These are round shaped,
air-cooled, reciprocating piston
engines that have an odd number
of cylinders in each row.
● Large frontal area giving lots of
parasite drag.
● Expensive to maintain.
Two-Stroke or Four-Stroke
Engines?
● There are two basic types of piston engines:
➢ Two-stroke
➢ Four-stroke
● Most certified aviation and automotive engines are four-stroke engines.
● Many Ultralights use two-stroke engines.
Four-Stroke Cycle
➢ Intake
➢ Compression
➢ Power
➢ Exhaust
Intake Stroke
● The first stroke of the piston.
● The intake valve is open, and the exhaust valve is closed, while the piston moves downward.
● This develops a vacuum in the cylinder.
● This vacuum then pulls the fuel and air mixture into the cylinder through the open intake valve.
Compression Stroke
● The second stroke of the piston.
● The intake and exhaust valves are closed as the piston moves upward.
● This will compress the mixture of fuel and air, increasing its total density.
● The compression allows this mixture to reach its maximum potency.
Power Stroke
● The third stroke of the piston.
● Both valves are still closed, initially.
● Prior to the piston reaching top dead centre, the spark plug fires, and this ignites the compressed fuel and air mixture.
● The mixture burns and expands, forcing the piston downward.
● Prior to bottom dead centre the exhaust valve opens, leads.
● The linear (up and down) motion of the piston is then converted to rotational motion by the crankshaft, through the connecting rod.
Exhaust Stroke
● The fourth stroke of the piston.
● The exhaust valve opens as the intake valve remains closed.
● The piston moves upward, forcing the burned gasses out of the cylinder through the exhaust valve.
● The intake valve will then open just prior to the piston reaching top dead centre, leading; and the exhaust valve will remain open, lagging, to help improve engine performance.
2 Methods of Cooling?
● Most certified piston-powered aircraft are air cooled by multiple fins on the crankcase and cylinders.
● Some piston engines are liquid cooled… WarBirds like the P51 Mustang, and some trainers like the Katana.
● This allows better control of the engine temperature, but is heavier and more complex, with the water jacket, radiator, pumps, and coolant.
What is a Magneto?
● An aircraft magneto is an engine driven electrical generator (independent of the aircraft’s alternator/battery) that uses
permanent magnets and coils to produce high voltage to fire the spark plugs.
● Aircraft magnetos are used in piston aircraft engines and are known for their simplicity and reliability.
Why do we have 2 Magnetos?
● Aircraft piston engines are designed with two independent ignition systems, made up of two spark plugs per cylinder.
➢ The left magneto fires one plug per cylinder, while the right magneto fires the other.
● This arrangement produces a smoother and more complete combustion of the fuel/air mixture while also providing ignition redundancy in the event one magneto should fail.
● Turning the mag switch OFF causes a short circuit (called grounding) of the magneto coil that prevents it from working.
➢ The wire that does the grounding is called a P-lead.
● By selecting the RIGHT magneto the left magneto is grounded and when selecting the LEFT magneto the right is grounded.
➢ The run-up check proves that each ignition system operates without help from the other one.
● The BOTH position of the mag switch removes the ground from both magnetos, and the engine uses the full dual system.
What is the reason for no RPM drop during the run-up?
● No drop in RPM during run-up could be an indication of a broken P-lead.
➢ You check this yourself by bringing the engine to idle RPM and placing the ignition switch to OFF momentarily.
● If the P-lead is broken the engine will continue to run. (mags are still “LIVE” not grounded when shut down.) MUST KNOW
● If the P-leads are good, the engine will begin to quit, placing the mag switch back to BOTH before the prop stops turning the
engine will restart and continue to run.
● Another cause for little or no RPM drop could be improper magneto timing.
Purpose of the Exhaust System?
● Used to reduce noise and take pollution away from the cabin area.
● By placing a shroud around the muffler it can be used to provide cabin heat. Caution!
➢ Due to the possibility of leaks in the exhaust system, careful inspections are required.
➢ Carbon monoxide poisoning is possible!!!
➢ If you smell exhaust, turn off the cabin heat.
What are the Ancillary Controls?
● These controls are also known as the auxiliary controls.
➢ Mixture Control
➢ Carburetor Heat Control
Basics on Mixture Control
● A rich mixture is lots of fuel and a lean mixture is reduced fuel.
● The fuel/air ratio is regulated with the mixture control.
➢ This adjusts the proportion of fuel/air by weight and is approximately 1:15 for a chemically correct mixture.
➢ 1:14 is the best power mixture
Why leaning the mixture?
➢ Save fuel
➢ Increase the efficiency of the engine
➢ Decrease the chance of spark plug fouling
➢ Keeps the combustion chamber clean which decreases the possibility of pre-ignition
