Exam1 Flashcards
What is an aircraft
A device that us used, or intended to be used, for flight according to the current Title 14 of the Code of Federal Regulations (14 CFR) part 1. General aviation aircraft are certified under 14 CFR part 23.
Light Sport Aircrafts
- Not designed to FAA standards, designed for low cost aircraft demands
- One motor, max 2 seats, fixed-pitch propellor, unpressurized cabin
Pitching
- Lateral Axis ( cat paws )
- Controlled by elevator
Rolling
- Longitudinal Axis (barrel roll)
- Controlled by ailerons
Yawing
- Vertical Axis (tea cup spin)
- Controlled by elevator (rudder)
Nose down force is a result of…
weight acting through the CG. Independent of airspeed.
Nose UP force is a result of …
the elevator and its dependance on airspeed
If the CG is to far forward …
then the nose-up force produced by the tail is to small and its difficult to raise the nose to flare during landing
Fuselage
center body. Holds crew/passengers/cargo
Wings
Attached to fuselage and main lifting surfaces
Empennage
Tail of aircraft which is attached to fuselage. Incorporates vertical and horizontal stabilizers and control surfaces.
Powerplant
whether a prop or a jet, always just an airprop
Landing gear
supports plane on the ground
Struts
Minimize structural requirements of high wing aircraft
What are wings made of?
Ribs (vertical) and stringers (horizontal)
What do wings support?
Ailerons and flap control surfaces
What material are wings made of?
- Smooth thin stressed metal or fabric skin.
- Airflows over the skin of the wing to produce lift
What other things can the wings accomodate?
Fuel tanks and retracted landing gear.
Empennage
Includes fixed and moveable horizontal and vertical control surfaces
Empennage vertical control surfaces
vertical stabilizer (top fin) and moveable rudder (top fin’s flap)
Empennage horizontal control surfaces
horizontal stabilizer and moveable elevator
Trim Tabs
A moveable elevator control surface.
Allows pilot to achieve zero stick force ( hands off ) level flight
What is alternate design for a horizontal stabilizer ?
Stabilator
Landing gear
- Tricycle is the most popular
- Trail draggers (like snow skis) > floats > retractable landing gear (allows plane to fly faster, but you have to remember to put them down)
Powerplant parts (4)
Includes engine, engine frame, propeller, and aerodynamic cowl
Where are jet engines
Often under wing or over wing pods
Powerplant definition
Air pumps. Creates a reward stream of air to push the plane forward. Newtons 3rd law.
Types of aircraft construction
- Truss, efficient but lack a stream lined shape. Good for bridges.
- Monocoque, use formers (hollow discs on the inside) , bulkheads (disc attached to the fuselage), and a stressed skin.
- Semimonocoque use formers, bulkheads, stringers and stressed skins.
Performance Instruments
- airspeed indicator
- altitude indicator
- altimeter indicator
- turn coordinator
- heading indicator
- vertical speed indicator
Control Instruments
- manifold pressure gauge
- altitude indicator
- tachometer
Navigation Instruments
- allows the AC to navigate point-to-point over the earth
- Glide slope data allows plane to land/takeoff in reduced visibility (in addition to a horizontal plane)
Air is a …. and the properties are …
FLUID!
Viscosity/Friction/Density/Pressure
What chemical elements make up the atmosphere
Nitrogen/oxygen/other gases
Atmospheric pressure, sea level
14.7 psi.
1 Hg per 1000 ft.
Pressure Altitude
altitude where the wieght of the atm. is 29.92 Hg
Find PA by setting altimeter to 29.92.
Window at 3’oclock position on the altimeter is called the kolsman window
Density Altitude
- Pressure altitude corrected for non-standard temp
- used to calculate aircraft performance
- higher density of air (lower density altitude) increases aircraft performance
How does an increase in pressure affect density altitude?
Lower DA
How does a decrease in temperature affect density altitude?
Lower DA
How does a increase in humidity affect density altitude?
Higher DA
Newtons Laws
1: A body at rest remains at rest
2: If a force hits a body the resulting acceleration is inversely proportional to the mass of the body and directly proportional to the applied force.
3. Equal and opp reaction
Bernoulli’s Principal
As flow speeds up, pressure goes down.
Airfoils have curved upper surface so the distance over the top is longer than the distance under the bottom
Continuity!
What is continuity
when the stream lines of a flow split over the shape , the must rejoin at the end of the shape.
Since the distance over the top is longer, the top stream must travel faster (lower pressure)
Wing Lift
pressure difference between top and bottom of wing
Airfoil Term: Leading Edge
rounded edge the divides the stream lines above and below the airfoil
Airfoil Term: Trailing Edge
Pointed shape where the stream lines rejoin after passing over and under the wing
Airfoil Term: Chord Line
straight line from the leading edge to the trailing edge. Chord is the width of the wing.
Airfoil Term: Mean Camber Line
curved line from the leading edge to trailing edge that is halfway between edges
Airfoil designs
check screen shot
Which airfoil has an abrupt stall and used for high performances AC
Laminar flow airfoil
AOA in accordance with the airfoil
angle between the chord and the free stream airflow in the front of the wing. Lift produced by the wing increases with AOA
Pressure Distribution and Behavior
Small neg AOA: balances pressure above and below wing, results in 0 lift
Small pos AOA: pressure on bottom higher than top and produces lift
How to get critical AOA
Increasing AOA increases lift until critical AOA is reached
Whats a stall
abrupt decrease in lift, not an absence.
When airflow separates from the upper surface of the wing.
Always occurs at the same AOA
Wing tip vortices
Air flow below the wing to wrap about the wing tip to the top of the wing. This rotating circulation is the wing tip vortex
How to avoid wing tip vorticies
land higher and longer than the preceding AC
Four forces of flight
- Lift: airflow around the wing
- Weight: downward pull of gravity
- Thrust: forward force that pull AC through the air
- Drag: backward, retarding force which limits speed of airplane
Drag
- Created when smooth air is disturbed
- Opposite direction of flight
- Opposes thrust and limits forward speed
- Induced or parasite
Parasite Drag
- When airspeed doubles, parasite drag doubles
- 3 Forms of parasite drag. Form/Interference/Skin Friction
Form/Profile Drag
Drag produced by an objects shape
Interference drag
generated by the mixing of airflow streamlines between airframe components such as the wing and the fuselage
Skin Friction drag
frost or ice, aluminum is bumpy under magnification
Induced Drag
- byproduct of lift
- occurs whenever a moving object redirects the airflow coming at it
Controls: Stick and Rudder
Traditional cable/pulley/spring/bell crank controls
Primary Flight Controls
rudder petals and control column are connected to rudder/ailerons and elevator by cables, bell cranks and springs.
Helicopter primary flight controls
Cyclic: controls AOA of rotter disc
Collective: controls AOA of rotter blades
Anti-torque petals: controls the force from the tail rudder
Aircraft control surfaces
- Alerions control roll
- Elevator/Stabilator control pitch
- Rudder controls yaw
- All controls must be used together for coordinated flight
Adverse Yaw
if pilot controls the alerions to bank right and the right wing produces more lift and drag. Unbalanced forces!
Elevator
- controls pitch
- pitch changes are the result of changing the force that the tail produced to counteract the pitch up tendency of the wing
Canards
AC with twin turboprop engines with a fixed t-tail
- good for yaw control
Yaw Control: Rudders and V-Tails
- Rudder is connected to vertical stabilizer and deflects to the right and left to induce yaw in the opp direction
- V-tail converts traditional rudder and elevator inputs into the V-tail surface. Produces less drag.
Wing Flaps
Change the shape of the wing to increase lift at low speeds
Leading Edge Devices
High lift devices can be added to the edge of the wing. Fixed slats/moveable slats/leading edge flaps/leading edge cuffs
Spoilers
High drag devices. Smaller ACs use speed brakes to avoid shock cooling the engine
Trim Tabs
Helps the pilot get back to level flight with zero stick force. Like the little weight on a doctors scale
Engine
- produces thrust to propel AC
- reciprocating and turboprop engines work in combination with a propeller to produce thrust
- Turbojet and turbofan engines produce thrust directly
Propeller
Converts mechanical energy to thrust
Adjustable-Pitch Propellers
Constant speed propellers optimize the blade angle to produce the highest thrust for every altitude, airspeed and power setting
Manifold pressure
measure of the power being produced
When both the manifold pressure and RPM needs to change, avoid over stressing the engine by:
- Power setting decreased: Reduce the manifold pressure before reducing RPMs
- Power setting increased: Increase RPM first and then manifold pressure
Induction
Air from combustion enters through an intake port on the front of the cowl
What are carburetor induction systems
carburetor induction systems mix fuel with air just before the engine intake ports
What are fuel injection systems
fuel injection systems mix with air just before of injects fuel into the cylinder
Float Carburator Systems
Prone to icing because of ideal gas law, PV=NRT.
Designed to operate at a FULL RICH mixture at sea level
Carburetor Icing
Float type carburetors are prone to icing due to the heat absorbed by fuel vaporization and decrease in air pressure. Conditions <70 and >80 humidity
Fuel injection advantages
- reduction in evaporative icing
- better fuel flow
- faster throttle response
- Precise mixture control
- Better fuel distribution
- Easier cold weather starts
Fuel injection disadvantages
- Hot starts are an issue
- Vapor lock (liquid fuel turns to vapor before it gets to the carburetor)
- restart after fuel starvation
Superchargers
engine air-driven pump or compressor that provided compressed air to the engine to provide additional pressure (weight of air) to the engine so it can produce additional power
Turbosuperchargers
Engine exhaust driven pump or compressor the provides compressed air to the engine to provide additional pressure (weight of air) to the engine so it can produce additional power
Allows engine to produce sea level power up to the critical altitude
Ignition
AC’s use dual magneto systems. Magnetos are direct engine driven devices that generate a high voltage magnet and distribute it to the spark plugs.
Oil Systems Benefits
- Lubrication of the engine’s moving parts
- Cooling of the system by reducing friction
- Removing heat from cylinders
- Providing a seal between the cylinder walls and pistons
- Carrying away contaminants
Key metrics for oil systems
pressure, temperature and volume
Engine cooling systems
cooling by oil and airflow, cowl flaps are used to increase airflow
What is an important lagging indicator?
Oil temperature
Exhaust systems
On each side of engine, be careful of carbon monoxide
Starting System
most aircrafts have automatic starters, can be supplied by external plug
Combustion
fuel air mixture burns in a predictable way while driving the piston down the cylinder
What causes detonation
- wrong fuel grade
- operation at higher temps and low RPM
- high power settings and a lean mixture
- Extended ground operations or long climbs during which cylinder cooling is reduced
what is detonation
uncontrolled ignition that can occur when the cylinder is on the up stroke
FADEC
Fully automatic digital engine control.
removes need for pilot to control fuel-air mixture
Turbine Engines
Air enters the front and leaves the back at a greater velocity. Difference is thrust, thrust is converted to mechanical
Types of turbine engines
- turbojet
- turboprop
- turbofan
- turboshaft
Turbine Instruments: Engine pressure ratio
measures difference between intake and exhaust pressure
Turbine Instruments:
Exhaust Gas Temperature
measures operating temp within engine
Turbine Instruments: Torquemeter
Measures the power output in psi, % or ft-lbs
Turbine Instruments: N1 and N2 Indicator
Rotational speed of the low pressure compressor presented in % of limit
Performance Comparison: Brake Horsepower
actual horsepower delivered to the shaft
Performance Comparison: Net Thrust
thrust produced by turbojet or turbofan engine
Fuel Systems
gravity feed is most common with high wing ACs.
Most ACs have 2 fuel pumps ( engine driven and 2 speed electrical)
Most have fuel selectors and notoriously bad fuel gauges
What allows the pilot is inject fuel into the cylinders for starting?
manual fuel primer
AVGAS comes in what grades
80 - 100 - 100LL
Jet fuel comes in 3 grades
JET A - JETA-1 - JETB
Reasons for fuel contamination
- Inadequate preflight check
- Servicing AC with improperly filtered fuel
- Storing aircraft with partially empty tanks
- Lack of proper maintenance
Heating Systems
- Fuel Fired heaters
- Exhaust heating systems
- Combustion heater systems
- Bleed air
Electrical Systems
- Alternator/generator
- Battery
- Master/battery switch
- Alternator/generator switch
- Bus bar, fuses, and circuit breakers
- Voltage regulator
- Ammeter/load meter
- Associated electrical wiring
Power consumers
- Position light
- anti-collision/landing lights
- Taxi Lights
- cabin lights
- instrument lights
- radio
- turn indicator
- fuel gauges
- stall warning system
- pilot heat
- starting motor
Position Lights colors
Red-left
Green-right
Hydraulic System parts
- reservoir
- hand, electrical, or engine driven pump
- filter
- selector valve that control direction of flow
- pressure relief valve
- actuator
Landing Gear Tricycle Benefits
Better breaking and visibility and resistant to ground looping
Conventional (tail wheel) Landing gear disadvantages
subject to ground loop - loss of lateral stability
Fixed and retractable landing gear
Fixed: simpler and stronger
Retractable: complex and reduces parasite drag and consumes fuselage volume
Pressurization benefits
Allows operation above 12,500 ft with O2
Instrumentation: Cabin/differential pressure indicator
cabin rate climb/descent
Oxygen Systems
Required at 12500 ft (30 min) and always above 14000
Oxygen bottles are a fire concern
Oxygen Delivery Systems
Oxygen masks/cannula`
Airfoil anti-ice systems
Heated leading edge
Windscreen/propeller anti-ice
Pilot Static Instruments: Altimeter
Aneroid wafers expand and contract relative to a reference pressure
airspeed indicator
measures difference between static and dynamic pressure
Inclinometer
depicts yaw. Step on a ball to coordinate a turn
wing will always stall at the critical AOA independent of:
weight, bank angle, temp, density altitude, CG
what is the difference between density altitude is and density in the atmosphere.
The density altitude is the altitude relative to standard atmospheric conditions at which the air density would be equal to the indicated air density at the place of observation. … In hot and humid conditions, the density altitude at a particular location may be significantly higher than the true altitude.
