Exam 1 Flashcards
Ch. 1-5
The fulcrum is at one end of the lever and the weight or resistance to be overcome is at the other end, with effort applied at some point between.
Third-Class Levers
Meaning to occupy space
Volume
What are the advantages of a wet sump system, compared to a dry sump?
A wet sump is attached to the bottom of the case, it is integral and complete, requiring no external parts and fittings to complicate installation and maintenance
No second (scavenge) pump is required
Chance of oil pump failure us reduced
This system can be operated in much colder ambient temperatures w/o concern that the oil congeal in the external lines
quantity which is useful when describing matter, especially when in the liquid or gaseous state
Density
Newton 3rd law
for every action there is an equal and opposite reaction
has neither a definite volume nor a definite shape.
gas
What is the relationship between aviation grade number and SAE numbers for lubricating oil?
Society of Automotive engineers divides all oils into groups according to viscosity at either 130F or 210F
Whagt forces are used to feather a propeller?
Centrifugal force
Resistance to motion is greatly reduced if an object is mounted on wheels or rollers
Rolling Friction
Prevents the escape of gas past the piston during engine operation
Compression Ring
Has a definite volume, but they take the shape of the containing vessel.
liquids
measure of the inertia of a body, and therefore is a measure of the quantity of matter associated with the body
Mass
Liquid cooled and air cooled with even number of cylinders. two in-line banks generally 30-60 degrees apart
V-type Engine
Work/Time
Power
What distinguishes a liquid from a gas?
Liquid has a definite volume, but they take the shape of the containing vessel. Gases not only take the shape of the containing vessel, but they expand and fill the vessel, no matter what it’s volume
The useful output of all aircraft powerplants is the
Force thrust
A feathered propeller will have a blade angle of approximately how many degrees?
90%
four-stroke cycle is?
Intake, compression, power, exhaust
The indicated horspower minus the brake horsepower
Friction Horsepower
What is the function of an augmenter tube?
Provide additional cooling airflow, especially for low speed, high power conditions (Climb)
How does opening cowl flaps affect engine cooling? Cabin cooling?
Open cowl flaps increase cooling over the engine and through the oil cooler
Hot and cold airflow into the cabin is reduced in most single engine installations due to reduced aur pressure inside and in front of the cowling when the cowl flaps are open
a force that results from the characteristic of particles of matter that causes attraction or pull on other particles of matter
Gravitation
Prevent leakage of gas pressure from the combustion chamber and reduce to a minimum the seepage of oil into the combustion chamber
Piston Ring
What is Force X Distance
Work
How are the cylinder walls lubricated in a typical opposed engine?
Oil sprayed from the crankshaft and crankpin bearings
How does the cowling contribute to the engine cowling?
Designed to force air over the cylinder cooling fins
The foundation of an engine.
Crankcase
The rate of doing work or the terms of work accomplished per unit of time
Power
Value of pressure of the standard day atmosphere at sea level
29.92 In of mercury
76 cm of mercury
- 7 psi
- 25 mb
34 ft of water
Basic components of a aircraft propeller
Blade Tip. The maximum reach of the blade from the center of the propeller hub.
Leading Edge. That part of the blade nearest the boat, which first cuts through the water.
Trailing Edge. That part of the blade farthest from the boat
Cup
Blade Face
Blade Back
Blade Root
Inner Hub
List three types of aircraft engine oils
Straight mineral oils-often used in reciprocating engines after overhaul
Ashless dispersant oil-usually replaces mineral oil after the piston rings have seated, as evidenced by decreased oil consumption
Synthetic oil
a substance which changes its shape easily and takes the shape of its container
Fluid
With a fixed RPM, does the propeller blade angle of attack increase or decrease as airspeed increases?
Decreases
What is the ‘flash point’ of a liquid?
Determined by laboratory tests that show the temperature at which a liquid will begin to give off ignitable vapors (flash) and the temperature at which there are sufficient vapors to support a flame
Used for timing of the valves. For a reciprocating to operate properly, each valve must open at the proper time, stay open for the required length of time, and close at the proper time
Valve-Operating Mechanism
Basic parts of a reciprocating engine
Crankshaft
Cylinders
Pistons
Connecting Rods
Valves
Valve-operating mechanism
Crankcase
List and describe 4 forces which act on an operating propeller.
Centrifugal: Outwards from the hub
Torque Bending: Twist, opposite rotations
Thrust Bending: Blades Bend Forward
Aerodynamic Twisting: Rotational Force about the center of pressure that tends to lower the blade angle
Define ‘propeller blade angle.’
The angle between the chordline of the blade and the plane of rotation
Portion of the engine in which the power is developed
Cylinder
Rotates at one-half the crankshaft speed
Camshaft
The amount of engine life obtained while maintaining the desired reliability
Durability
the power delivered to the propeller for useful work.
Brake Horsepower
power developed in the combustion chambers without reference to friction losses within the engine
Indicated Horsepower
List two types of engine lubrication (oil) pumps. WHich one is on all aircraft reciprocating engines?
Dry sump
Wet sump-> all aircraft reciprocating engines
When a resistance is overcome by a force acting though a measurable distance
Work
What component(s) in the governor oppose the force of the speeder spring?
Flightweight and the pilot valve
What is the ‘cloud point’ of a liquid?
Helps indicate suitability
The temperature at which its wax content, normally help in solution, begins to solidify, and separate into tiny crystals causing oil to appear cloudy or hazy
Characteristic of matter that resists change in motion(velocity and direction)
Inertia
What are the four states of matter?
Solids, Liquids, Gases, and Plasma
provides a place for combustion of the fuel/air mixture and to give the cylinder more heat conductivity for adequate cooling
Cylinder heads
Has a definite volume and a definite shape
Solid
The distance the piston moves from one end of the cylinder to the other
Stroke
List all the useful functions of lubricating oil within the engine
Reduces friction
Cushion between metal parts
Absorbs heat from the parts
Reciprocating engines are especially dependent on the oil for cooling
Seal between the piston and the cylinder wall
Reduces abrasive wear
Cleansing the engine
The fulcrum at one end: the effort is applied at the other end
Second-Class Levers
The link which transmits forces between the piston and the crankshaft
Connecting rods
Consists of a row, or rows of cylinders arranged radially about a central crankshaft
Radially Engine
What are the differences between inertia and momentum?
Inertia: a property of matter by which it continues in its existing state or rest or uniform motion in a straight line unless that state is changed by an external force
Momentum: the quatntity of motion of a moving body, measured as a product of it’s mass and velocity
On a shot-field takeoff, what can the pilot do to reduce FHP and thus increase BHP and THP?
the break horse power at full throttle to over come any slight FHP
List five functions of aircraft engine oil
Absorbs heat
Cools the engine
Seals
Reduce abrasive wear
Cleanses the engine
A comparison of the weight of the substance to the weight of an equal volume of distilled water at a specified temperature
Specific Gravity
Define ‘propeller angle of attack.’
The angle between a line drawn along the face of the propeller blade and a line scribed by the plane of rotation
Two banks of cylinder opposite each other with a crankshaft in the center. Low weight to horsepower ratio. Its comparative free from vibration
Opposed or O-type Engine
Acts as a moving wall within the combustion chamber
Piston
Genreal requirements for all engines
efficiency, economy, and reliability
Three kinds of friction are?
Static, Dynamic, and Rolling
Define effective and geometric pitch of a propeller.
Effective: the distance it actually advances
Geometric: distance a propeller should advance in one revolution
Made up of very hot ionized gas
Plasma
The ability to do work
Energy
The resistance to motion offered by an object sliding over a surface
Dynamic(Sliding) Friction
Newtons 1st Law
Objects at rest will remain at rest
name commonly used for the gravitational force of attraction between the earth and a body(mass) near the earth
Weight
Joins the piston to the connecting rod
Piston Pin
What kind of lever is your forearm
3rd Class
What is the most effective propeller angle of attack for take off?
15%
What kind of lever is a hydraulic wobble pump handle?
3rd Class
List and define all types of propellers
Fixed-Pitch Propeller- The blade is generally not changed after the propeller is built
Ground-Adjustable Propeller-The pitch or blade angle can be changed when the propeller is not turning
Controllable-Pitch Propeller-permits a change of blade or angle while the proppeler is rotating
Constant-Speed Propeller-designed to automatically change its blade pitch to allow it to maintain a constant RPM, irrespective of the amount of engine torque being produced or the airspeed or altitude at which the aircraft is flying.
Reverse-Pitch Propeller-acontrollable propeller in which the blade angle can be changed to a negative value during operation
Feathering Propeller-controllable propeller having a mechanism to change the pitch to an angle so that forward aircraft motion produces a minimum windmilling effect on a “power-off” propeller
Tractor Propeller-mounted on the up-stream end of a drive shaft in front of the supporting structure
Pusher Propellers-mounted on the downstream end of a drive shaft behind the supporting structure
Define ‘propeller slip.’
The difference between geometric and effective pitch
Examples to know
The fulcrum is located between the effort and the resistance
First-Class Levers
Regulates thickness of the oil film on the cylinder wall
Oil Control rings
The result of the engine and the propeller working together
Thrust Horsepower
Briefly outline the difference in operation for a light single engine and multi-engine aircraft propeller system.
Single: constant speed, non-feathering
Multi: constant speed, feathering
Newtons 2nd law
When forces act upon a body, the momentum of the body can be changed
The section to which the connecting rod is attached
Crankpin
Four type of reciprocating engines
In-line, Opposed, V-type, and Radial
What 3 energy forms does the recipricating engine utilize or convert?
Chemical
Heat
Mechanical
Why is viscosity important when selecting a lubricant?
Resistance of oil to flow
Generally has even # of cylinders, small frontal area and better adapted to streamlining
In-Line Engines
The ability to convert fuel into heat energy then into mechanical energy by the flow of some fluid mass through the engine
Heat Engine
The resistance of an oil to flow
Viscosity
Under what conditions would a dry sump system be advantageous, over a wet sump?
During radial engings because oil cannot be carried inside the engine itself
During inverted flight
What is the difference between satic and dynamic balancing?
Static: a propeller suspended by a drawstring
Dynamic: Electrical machine w/ vibration analysis of the aircraft
What kind of lever is the A/C control yoke withr espect to aileron movement
2nd Class
any device with which work may be accomplished. transforms energy
Machine
The backbone of the reciprocating engine. Tranforms the recipricating motion of the piston and connecting rod into rotary motion for the rotation of the propeller
Crankshaft
Define thermal shock.
Occurs when engine parts that are operating at high temperatures are quickly cooled
What are the differences between a two position and a ground adjustable propeller?
Ground Adjustable: operates as a fixed pitch propeller; can only be changed whent he propeller is not turning
Two-position controllable propeller: Permits a change of blade pitch, or angle, while the propeller is rotating
The force necesary to start the body moving slowly
Static(Starting) Friction
