Chapter 5 operation of systems Flashcards
4 main control surfaces
- Elevators— control the movement of the plane about its lateral axis. PITCH
- Ailerons— controls the airplanes movement about its long. Axis
- Rudder— controls movement of the plane about its vertical axis. YAW
- Trim Tabs— are small, adjustable hinged surface on the aileron, rudder, or elevator control surfaces. Labor saving devices allow pilot to release manual pressure on the primary control
Flight controls operated
Flight control surfaces are manually actuated through the use of either rod or cable system. Control wheel actuated the ailerons and elevator, rudder/braked pedals actuate the rudder
Flaps fucntion
Moveable panels on the inboard trailing edges of the wings. Are hinged so that they may extend downward into the flow of air beneath the wings to increase both lift and drag. Permits slower airspeed and a steeper angle of descent during landing approach. Also shorten takeoff distance
Landing gear system
Consist of tricycle system utilizing two main wheels and a steerable nosewheel. Turbulence spring steel main gear struts provide main gear shock absorption, nose gear shock absorption is provided by combination air/oil shock strut
Braking system
Hydraulically actuated disc-type brakes are utilized on each main gear wheel. Hydraulic line connects each brake to a master cylinder located on each pilot;s rudder petals. By applying pressure to the top of either the pilot’’s or copilot’s set of rudder pedals, the brakes may be applied
Hydraulic fluid
Mineral based hydraulic fluid(MIL-H-5606) odor similar to penetrating oil and dyed red
Steering on ground
Nose wheel steering through simple system of mechanical linkage connected to the rudder pedals. When rudder petal depressed, spring loaded bungee(push pull rod) connected to the pivotal portion of a nosewheel strut will turn the nosewheel
What engine does plane have
Horizontally opposed four-cylinder, overhead-valve, air cooled carbureted engine
4 strokes occur in cylinder
Intake- piston starts its downward travel causing intake valve to open and the fuel air mixture to be drawn into the cylinder
Compression— beings when the intake valve closes, and the piston starts moving back to the top of the cylinder. This phase of cycle is used to obtain a much greater power output from the air mixture once its ignited
Power—begins when the fuel air mixture is ignited which causes tremendous pressure increase in the cylinder and forces the piston downward away from the cylinder head, creating the power that turns the crankshaft
Exhaust— is used to purge the cylinder of burned gases and beings when the exhaust valve opens, and the piston starts to move toward the cylinder head once again
SUCK, SQUEEZE, BANG, BLOW
Carburetor
Process of mixing fuel and air in the correct proportions so as to form a combustible mixture. Vaporizes liquid fuel into small particles and mixes it with air. It measures the airflow and meters fuel accordingly
Carburetor heat system
Carb. Heat valve (controlled by pilot) allows unfiltered heated air from a shroud located aroun an exhaust riser or muffler to be directed to the induction air manifold prior to the carburetor. Carburetor heat should be used anytime suspected or known carb. Icing conditions exist
What change occurs when applying carb heat
Introduction of heated air into the carb. Will result in a richer mixture. Warm air is less dense, resulting in less air from the same amount of fuel. Use of carb can cause a decrease in engine power of up to 15%
Throttle function
Allows pilot to manually control the amount of fuel/air charge entering the cylinders. This in turn regulates the engine speed and power
Mixture control
Regulates fuel-to-air ratio. All planes incorporate mixture control, which the fuel/air can be controlled by the pilot during flight. Prevents the mixture from becoming too rich at high alts, due to decreasing air density. Lean mixture during cross country to conserve fuel and provide optimum power
Fuel injection system
Injects fuel directly into the cylinder or just ahead of the intake valve
- Engine driven fuel pump- provides fuel under pressure from the fuel tank to the fuel/air control unit
- Fuel/air control unit- meters fuel based on the mixture control setting and sends it to the fuel manifold valve at a rate controlled by the throttle
- Fuel manifold valve- distributes fuel to the individual fuel discharge nozzles
- Discharge nozzles- located in each cylinder head, these inject the fuel /air mixture at the precise time for each cylinder directly into each cylinder intake port
- Auxiliary fuel pump - Provides fuel under pressure to fuel/air control unit for engine starting and/or emergency use
- Fuel pressure/flow indicators - measures metered fuel pressure/flow
Ignition system the plane has
Engine ignition is provided by 2-engine driven magnetos, and two spark plugs per cylinder. Completely independent of the electrical system. Magnetos are engine-driven self contained units supplying electrical current without using an external source of current.
Two main advantages of dual ignition
A. Increased safety in case one system fails the engine may be operated on the on the other
B. More complete and even combustion of the mixture, and consequently, impr9ved engine performance I.e. the fuel/air mixture burn toward the center
Fuel system type
Gravity feed. Flows from two wing fuel tanks to a fuel shutoff valve and on the ‘on’ position allows it to flow thru. The fuel is mixed with air and then flows into the cylinders thru the intake manifold tubes
Purpose of fuel tank vents
Fuel level in an aircraft fuel tank decreases,, a vacuum would be created within the tank which eventually result in a decreasing fuel flow and finally engine stoppage. Replaces fuel with outside air, prevents vacuum
Fuel pump
These plans do not have fuel pump
Fuel type
Fuel grade used is 100LL and color blue
Manual primer
Primer’s main function is to provide assistance in starting the engine. The primers draws fuel from the fuel strainer and injects it directly into the cylinder intake ports. Results in quicker, more efficient engine start
Electrical system
28 volt, direct current system powered by an engine-driven 60 amp alternator and 24 volt battery
Circuits
Are protected from an overload condition by either circuit breakers or fuses or both. Same function as fuses except when overload, circuit breakers can be reset
Electrical system provides power for
Radio Turn coordinator Fuel gauges Pitot heat Landing light Taxi light Strobe lights Interior lights Instrument lights Position lights Flaps (maybe) Stall warning system Oil temperature gauge Electric fuel pump
Ammeter
Indicates the flow of current in amperes, from the alternator to the battery or from the battery to the electrical system with the engine running and master switch on, ammeter will indicate the charging rate to the battery. If off-line and is no longer functioning or electrical load exceeds output of the alternator. Indicates discharge
Voltage regulator
Device which monitors system voltage, detects changes, and makes required adjustments in the output of the alternator to maintain regulated system. Does it a low and high RPM
Generator/alternator voltage output slightly higher than battery voltage
The difference in voltage keeps the battery charged, 12 volt battery would be supplied with 14 volts
Cabin heat
Fresh air, heated by an exhaust shroud, is directed to the cabin through a serious of ducts
How is temp controlled in cabin
Controlled my mixing outside air(cabin air control) with heated air (cabin heat control) in a manifold near the cabin firewall. This air is then ducted to vents located on the cabin floor
5 basic functions of aircraft engine oil
Lubricates- the engines moving parts
Cools- the engine by reducing friction
Removes- heat from the cylinders
Seals- provides a seal between the cylinder walls and pistons
Cleans - by carrying off metal and carbon particles and other oil contaminants
How carb icing occurs
Vaporization of fuel, combined with expansion of air as it passes thru the carb, causing sudden cooling of mixture. The temp of air passing through the carb may drop as much as 60F within a fraction of a second. Water vapor is squeezed out by the cooling and if temp in carb reaches 32F or below, moisture will be deposited as frost or ice inside the carb
Indication of carb icing
In fixed pitch plane, first indication is loss of RPM
Controllable pitch, drop in manifold pressure
Method in determine carb ice has been eliminated
When heat is first applied will be drop in RPM and if ice is present there will be a rise in RPM (usually with engine roughness) and when carb heat is turned off RPM will rise to a setting greater than that before application of heat and engine should run more smoothly
What conditions are favorable for carb icing
When temps are below 70F and the relative humidity is above 80%. But because of sudden cooling that takes place in carb icing can occur even with temp as high as 100F and humidity as low as 50%
Anti icing equipment
Prevents ice from forming on certain protected surface.
Examples: heated pitot tubes and static ports, carb heat, heated fuel vents, prop bladed with electrothermal boots, and heated windshields
Deciding equipment
Removes ice that has already formed on protected surfaces. Pneumatic boots on the wing and tail leading edges
How decking system works
Upon actuation, boots attached to the wing leading edges inflate with air from pneumatic pump to break off accumulated ice. After few seconds of inflation they are deflated back to their normal position with vacuum assistance
Detonation
Is uncontrolled explosive ignition of the fuel/air mixture within the cylinders combustion chamber. Causing excessive temp and pressure which, if not corrected, can quickly lead to failure of the piston, cylinder, or valves. Can also cause engine overheating, roughness, or loss of power. Detonation is characterized by high cylinder head temperatures and most likely occur at high power settings
Operational causes of detonation
A. Using lower fuel grade
B. Operating with extremely high manifold pressure in conjunction with low RPM
C. Operating the engine at high power settings with an excessively lean mixture
D. Extended ground operations or steep climbs where cylinder cooling is reduced
What action should be taken if detonation is suspected
A. Ensure that proper grade of fuel is used
B. Keep the cowl flaps in full open position while on ground
C. Use an enriched fuel mixture, as well as a shallow climb angle, to increase cylinder cooling during takeoff and initial climb
D. Avoid extended, high power, steep climbs
E. Develop habit of monitoring the engine instruments to verify proper operation according to procedures established by the manufacturer
Preignition
When fuel/air mixture ignites prior to the engines normal ignition event resulting in reduced engine power and high operating temp. Premature burning usually caused by a residual hot spot in the combustion chamber, often created by a small carbon deposit on a spark plug, cracked spark insulator or other damage in the cylinder that causes a part to heat sufficiently to ignite the fuel/air charge.
Can cause severe engine damage, because the expanding gases exert excessive pressure on the piston while still on its compression stroke
