Showing posts with label
Module 13 Aircraft Aerodynamics.
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Showing posts with label
Module 13 Aircraft Aerodynamics.
Show all posts
1. Basic Aerodynamics
- Lift is the upward force that opposes weight.
- Drag is the air resistance acting opposite to motion.
- Thrust moves the aircraft forward.
- Weight acts downward through the center of gravity.
- The four main forces on an aircraft are lift, weight, thrust, and
drag.
- Bernoulli’s principle explains lift as pressure difference.
- Newton’s third law also contributes to lift generation.
- The wing’s shape is called an air foil.
- Angle of attack is the angle between chord line and airflow.
- When angle of attack exceeds the critical angle stall occur.
2. Flight Controls
- Primary flight controls are ailerons, elevators, and rudder.
- Ailerons control roll about the longitudinal axis.
- Elevators control pitch about the lateral axis.
- The rudder controls yaw about the vertical axis.
- Secondary flight controls include flaps, spoilers, and trim tabs.
- The secondary Flt Control Flaps increase lift and drag for landing
and takeoff.
- Slats delay airflow separation and prevent stall.
- Spoilers destroy lift and assist braking.
- Trim tabs reduce pilot control effort.
- Fly-by-wire systems use electrical signals instead of cables.
3. Aircraft Structures
- The fuselage houses crew, passengers, and cargo.
- The wing generates lift and supports fuel tanks.
- The empennage includes the tailplane and fin.
- The horizontal stabilizer provides pitch stability.
- The vertical fin provides directional stability.
- The landing gear supports aircraft on the ground.
- Semi-monocoque structure uses frames, stringers, and skin.
- Composite materials are strong and lightweight.
- Stress is internal resistance to external load.
- Fatigue is caused by repeated loading cycles.
4. Powerplant Systems
- The powerplant provides thrust.
- Turbofan engines are used in most modern airliners.
- A propeller driven through a reduction gearbox in Turboprop engines.
- The compressor increases air pressure.
- The combustion chamber mixes air with fuel and burns it.
- The turbine extracts energy to drive the compressor.
- The exhaust nozzle accelerates the gases for thrust.
- The accessory gearbox drives engine accessories.
- FADEC controls engine parameters automatically.
- Engine fire extinguishing systems use halon or clean agents.
5. Landing Gear Systems
- The landing gear absorbs landing shock loads.
- Main and nose gear support the aircraft on the ground.
- Oleo struts use oil and air for shock absorption.
- Retraction and extension are powered hydraulically or electrically.
- Uplocks and down locks secure gear position.
- Proximity sensors indicate gear position.
- Anti-skid systems prevent wheel lockup.
- Brake fans help in cooling brakes.
- Nose wheel steering is hydraulically or electrically operated.
- Tires are nitrogen inflated to prevent fire risk.
6. Hydraulic Systems
- Hydraulics transmit force using pressurized fluid.
- Pascal’s law governs hydraulic pressure transmission.
- Typical operating pressure is 3000 psi.
- Hydraulic pumps supply system pressure.
- Reservoirs store hydraulic fluid.
- Filters remove contamination.
- Accumulators store pressure energy.
- Relief valves protect against overpressure.
- Actuators convert pressure to movement.
- Skydrol is a commonly used phosphate ester hydraulic fluid.
7. Pneumatic and Air Systems
- Pneumatic systems use compressed air.
- Air can be supplied from the APU, engines, or ground source.
- Pneumatics power de-icing, pressurization, and engine start.
- Check valves prevent backflow.
- Pressure regulators control system pressure.
- Safety valves prevent overpressure.
- Air cycle machines condition the cabin air.
- Bleed air is tapped from compressor stages.
- Leak detection systems monitor pneumatic ducts.
- Isolation valves control system routing.
8. Electrical Systems
- The electrical system provides power to aircraft components.
- Power sources include generators, batteries, and external power.
- AC and DC systems are both used in modern aircraft.
- The constant speed drive maintains generator frequency.
- The busbar distributes electrical power.
- Circuit breakers protect against overloads.
- Relays and contactors control heavy current circuits.
- Batteries provide power during engine start.
- Inverters convert DC to AC power.
- TRUs convert AC to DC.
9. Air Conditioning & Pressurization
- Cabin pressurization maintains a comfortable atmosphere.
- Outflow valves control cabin pressure.
- Cabin altitude should not exceed 8,000 feet.
- Air conditioning controls temperature and humidity.
- Air cycle machine cools bleed air using expansion.
- Recirculation fans improve air distribution.
- Temperature controllers regulate cabin zones.
- Pressure relief valves prevent over pressurization.
- Safety valves protect structure during decompression.
- Cabin pressure differential must stay within structural limits.
10. Flight Instruments & Avionics
- The pitot-static system provides airspeed, altitude, and VSI data.
- Pitot tube measures dynamic pressure.
- Static port measures atmospheric pressure.
- Altimeter displays height above sea level.
- Airspeed indicator shows speed relative to air.
- Vertical speed indicator shows rate of climb or descent.
- Attitude indicator shows aircraft pitch and roll.
- Heading indicator shows aircraft direction.
- Radio altimeter measures height above ground.
- Flight data recorder and CVR record flight information for safety.