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35 Cards in this Set
- Front
- Back
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Type of engines |
1. Piston engines - drives propellers - used in small aircraft (less than 5700kg)
2. Jet engines (gas turbines) - used in modern transport aircraft (typical 393000kg) |
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Propellers construction |
- consists of 2 or more blades attached to a central hub which is mounted on an engine crankshaft |
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Propellers blade |
have a - leading edge - trailing edge - tip - shank - face and back angel between the propeller |
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what is the blade angle and draw it |
angle between the propeller plane of rotation and the chord line of a propeller airfoil section |
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Pitch |
distance in inches that a propeller section will move forward in one revolution |
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pitch distribution |
gradual twist in the propeller blade from shank to tip |
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draw the propeller |
draw it |
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how does it produce lift |
by aerodynamic action and pulls aircraft forward |
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amount of lift depends on |
-airfoil shape -revolution speed of engine -angle of attack of propeller blade section |
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- fixed pitch propeller |
-pitch of propeller remains the same |
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most desirable angle of attack |
between 2 to 4. with any above 15 being ineffective |
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Piston engines construction |
- number of cylinders which pistons moves up and down - in each cylinder, fuel/air mixture is burned, heat energy causes gas to expand and drive the piston down the cylinder - piston connected by a rod to a shaft which it turns - connecting rod connect the top down motion of the piston into a rotary motion of the crankshaft which transmit power generated by the engine to the propeller - light aircraft with fixed pitch propeller and constant speed propellers have propellers directly coupled to the crankshaft (propeller shaft = crankshaft)
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draw the otto cycle |
1. induction 2. compression 3. expansion 4. exhaust |
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Jet engine types |
1. ram jet 2. pulse jet 3. rocket jet 4. gas turbine 5. turbo rocket
differs in the thurst provider and the way it convers energy into power for flight |
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when should use jet vs propeller type engine |
use propeller at speed below 450miles per hour because propulsive efficiency largely depends on fwd speed |
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difference between gas turbine engine and 4 stroke piston engine |
gas turbine -combustion occurs at constant volume - eliminates 3 idle strokes, enable more fuel to be burnt thus greater power for a given size engine
4 stroke piston engine - combustion occurs intermittently (only one stroke is utilized in the production of power others are for charging, compressing and exhausting) |
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draw the turbo jet engine |
draw it |
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draw the piston engine |
draw it |
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fuel system |
-store fuel and deliver it to the carburettor (or fuel injection system) in adequate quantites at the proper pressure under all normal flight condition - change of altitude - change of attitude - sudden acceleration - deceleration of engine |
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attitude |
orientation of aircraft relate to direction of travel |
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where is the fuel tank installed |
in the wing |
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fuel tank construction |
- sump and a drain point at the lowest - point of tank allow having Impurities (such as water) to gather, be inspected and drowned off - contains baffles to stop the fuel surging about in flight, esp with large attitude change / turbulence - top of fuel tank is vented to the atmosphere to allow atmospheric pressure to be retained in the tank as altitude is changed and fuel is used up - any reduced pressure (due to ineffective venting) in the tank could reduce rate of fuel flow to the engine and also caused fuel tank to collapse inwards - fuel vent should be checked in the preflight external inspection to ensure not blocked or damaged |
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draw the fuel tank |
draw it |
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when might the fuel volume be increased |
- can increase due to fuel in the tank warming up in the sun. -> causes space to expand |
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how is fuel fed to the airplane |
high wing aircraft -> gravity fed with a carburettor
low wing aircraft -> if no carburettor then electric boost pump assistance |
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describe the electric boost pump |
- prior to startup, electric auxillary boost bump is used to prime the fuel line and purge any vapour from fuel lines - once engine starts, engine driven mechanical fuel pump takes over - important that fuel strainer drain valve is checked closed during pre flight, if not closed, engine driven fuel pump may not be able to draw sufficient fuel into the engine - it is usual to have electric fuel pump switch on for critical manoeveuer such as take off and low level flying in case of mechanical failure |
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types of hydraulic system |
1. Jack or actuator |
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Jack or actuator |
- converts hydraulic pressure into mechanical energy and comprises of a cylinder in which is fitted a piston and piston rod or ram - 2 pipe connection - hydraulic fluid is fed under pressure from a control valve |
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draw undercarriage |
- fluid enter pipe connection on the left of jack - pressure of fluid exert force on piston moving undercarriage down by forcing piston and jack to right - fluid which is not under high pressure will exert on the right aka return fluid |
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resevoir |
- supplies a reserve of hydraulic fluid to compensate for minor leakage in the system and provides a storage space for the returning hydraulic fluid |
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pump |
driven by aircraft engine and simply termed the Engine Drive Pump (EDP) |
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control valve |
can be mechanically operated by the pilot or electrically operated |
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aircraft system powered by hydraullic |
1. rudder 2. elevator 3. aileron 4. flaps 5. speed brakes and group spoilers 6. auto pilots 7. normal / alternate brake 8. landing gear 9. nost wheel steering |
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hydrallic wheel brake system |
- disk brakes on the man wheels - hydrallically operated by toe brakes which are situated on top of the rudder pedals - left brake - slow down left main wheel - right brake - slow down right main wheel provides differential braking |
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draw the hydrallic wheel brake system |
- as toe brake is pressed, toe pressure transmitted by the hydralic fluid to a slave cylinder which closes the brake friction pad onto the brake disc - brake disc slows the rotation |
