Aircraft Forces Quiz 1 PDF

**QUIZ 1** 1. 2. 3. 4. 5. **Forces Acting on an Aircraft :** **Thrust**: The forward force generated by the engine and propeller, pushing the aircraft forward. **Drag**: Resistance that opposes forward motion, divided into: **Induced Drag**: Produced by lift-generating parts like the...

**QUIZ 1** 1. 2. 3. 4. 5. **Forces Acting on an Aircraft :** **Thrust**: The forward force generated by the engine and propeller, pushing the aircraft forward. **Drag**: Resistance that opposes forward motion, divided into: **Induced Drag**: Produced by lift-generating parts like the wings. **Parasite Drag**: Non-lift-related drag, such as form drag and skin friction. **Lift**: Upward force that opposes weight, generated by the wing due to air pressure differences caused by the airfoil shape and angle of attack. **Weight**: Downward force due to gravity, pulling the aircraft towards the Earth. **2. Lift :** **Bernoulli's Principle**: Lift is generated as faster-moving air over the wing's curved surface creates lower pressure above, while slower air below maintains higher pressure, lifting the aircraft. **Newton's Third Law**: The action of deflecting airflow downwards results in an upward lift force. **Factors Affecting Lift**: Air density, velocity, wing surface area, and angle of attack. Higher velocity and larger wings increase lift. **3. Drag :** **Induced Drag**: By-product of lift, caused by wingtip vortices, more prevalent at slow speeds and high angles of attack. **Parasite Drag**: Increases with speed, consisting of form drag (caused by shape), skin friction, and interference drag (disturbance of airflow where parts meet). **Ground Effect**: Reduced drag near the ground as wingtip vortices are restricted. **4. Thrust :** Generated by propellers or jet engines, thrust overcomes drag to keep the aircraft moving forward. Adjusting thrust controls airspeed. **5. Weight :** Acts through the center of gravity, balancing the forces of lift. Improper weight distribution affects flight stability and performance. **6. Couples :** **Couples** are formed when forces like weight, lift, drag, and thrust act at parallel but separate points, causing turning moments. For example: Weight ahead of lift causes the nose to pitch down. Drag above thrust causes the nose to pitch up. **7. Design of the Wing :** **Airfoil Camber**: Affects lift, with deeper camber providing higher lift but more drag. **Planform**: The shape of the wing as seen from above (rectangular, tapered, elliptical, delta). Each shape affects lift production and stall characteristics. **Aspect Ratio**: The ratio of wingspan to chord length, influencing induced drag. Higher aspect ratios reduce drag. **Angle of Incidence**: The fixed angle between the wing chord line and the airplane's longitudinal axis, optimized for efficient cruising. **8. Axes of the Airplane :** **Longitudinal Axis (Roll)**: Controlled by ailerons, affecting banking and rolling movements. Lateral stability **Lateral Axis (Pitch)**: Controlled by elevators, affecting nose-up or nose-down movements. Longitudinal stability **Vertical Axis (Yaw)**: Controlled by the rudder, affecting left or right yaw movements. Directional stability. **9. Stability :** Stability is affected by weight distribution, design of the wing, and the location of control surfaces. **Dynamic Stability**: Refers to the aircraft's ability to return to steady flight after being disturbed. Poor balance between forces can lead to instability. **10. Effects of Propellers :** **Torque**: Propeller rotation causes a left-turning tendency counteracted by the rudder. **P-Factor**: Asymmetric thrust at high angles of attack causes yawing. **Slipstream**: Spiraling air from the propeller strikes the tail, causing yaw. This can be corrected with trim tabs or rudder. **11. Climbing and Gliding :** **Climbing**: Achieved by increasing the angle of attack and applying power. The airplane reaches equilibrium once a steady rate of climb is established. **Gliding**: With no engine power, the descent is controlled by the angle of descent and the balance of lift, drag, and weight. Best glide speed ensures maximum range. **12. Turns :** In a turn, lift is divided into vertical and horizontal components. The horizontal component acts as centripetal force, turning the airplane. The vertical component must be increased by pulling back on the controls to maintain altitude. **Spiral Dives :** **Definition**: A steep, descending turn with an excessive nose-down attitude, resulting in rapidly increasing airspeed and rate of descent. **Characteristics**: Excessive angle of bank. Rapidly increasing airspeed. Rapid descent. **Differences from Spins**: In a spiral dive, the airspeed continuously increases, whereas, in a spin, airspeed remains low and constant. **Dangers**: Risk of structural damage if airspeed limits are exceeded. High load factors during recovery can cause stress on the airframe. **Recovery**: 1\. Close the throttle to reduce power. 2\. Level the wings as quickly as possible. 3\. Ease out of the dive gently to avoid overstressing the aircraft. 4\. Resume straight and level flight. **Airspeed Limitations :** **V\_S (Stall Speed)**: Minimum speed at which the aircraft can maintain steady flight. **V\_A (Maneuvering Speed)**: Maximum speed for safe abrupt control deflection or operation in turbulence. This speed decreases with a reduction in aircraft weight. **V\_FE (Flaps Extended Speed)**: Maximum speed permissible with flaps extended. **V\_NO (Maximum Structural Cruising Speed)**: Maximum safe speed for normal operations, designed for structural integrity in turbulent air. **V\_NE (Never Exceed Speed)**: Maximum speed that the aircraft can safely operate in smooth air without risking structural failure. **Stalls :** **Factors Affecting Stalls**: **Weight**: A heavier airplane requires more lift, which leads to a higher angle of attack and an increased stalling speed. **Center of Gravity**: As the center of gravity moves forward, the stalling speed increases. **Turbulence**: Sudden changes in airflow can cause an abrupt increase in the angle of attack and induce a stall. **Turns**: During turns, the increase in load factor raises the stall speed. **Flaps**: Lower the stall speed by increasing lift but at the cost of higher drag. **Surface Contamination**: Frost or ice on the wings reduces the lifting ability and increases stall speed. **Stall Recovery**: 1\. Lower the nose to reduce the angle of attack. 2\. Increase airspeed by accelerating. 3\. Return to stable flight conditions. **Spins :** **Definition**: A spin is a condition where the aircraft enters autorotation after a stalled condition, characterized by simultaneous yaw, roll, and pitch about a spin axis. **Stages of a Spin**: **Incipient Spin**: From stall to the point where the spin becomes established. **Developed Spin**: The spin stabilizes with predictable rates of rotation and descent. **Recovery**: Initiating recovery actions to break the spin. **Recovery Procedure**: 1\. Idle power. 2\. Neutralize ailerons. 3\. Apply full rudder in the opposite direction of the spin. 4\. Push the control column forward to un-stall the aircraft. 5\. Once the rotation stops, neutralize the rudder and level the wings. QUIZ 2 **Pitot static instruments** Airspeed indicator Pitot and static source Altimeter Static source Vertical speed indicator Static source Pitot tube, three openings 1. Pitot source 2. Static source 3. Water drain **Altimeter** Pressure of atmosphere (up in altitude equals down in static pressure) **[Indicated Altitude]** - Reading on the altimeter when it is set to the current pressure **[Pressure Altitude]** - Reading on the altimeter when it is set to standard pressure **[Density Altitude ]** - Pressure altitude corrected for temperature **[True Altitude]** - Exact height above mean sea level **[Absolute Altitude ]** - Actual height above the earth\'s surface **Altimeter-pressor error** indicated altitude above sea level Pressure changes over the Horizontal distance Low = over reading High = under reading "from high to low look out below" Altimeter Temperature error Cold = lower true altitude Warm= Higher true altitude "from warm to cold look out below" **Altimeter errors** - Mountain effect error: Winds deflected around large, single mountain peaks, or through valleys, tend to increase speed = decrease in pressure - Can extend as far as 100 miles downwind of the mountains **Airspeed indicator** - Indicates how fast the aircraft is flying through the air - Measures the difference between dynamic (pitot) & static pressure  - **Indicated Airspeed (IAS)?** - Airspeed as read from the ASI - **Calibrated Airspeed (CAS)?** - IAS corrected for instrument and installation error - **True Airspeed?** - CAS corrected for density and temperature - The actual speed of the aircraft through the air - **Equivalent Airspeed (EAS)?** - CAS corrected for compressibility factor Density error density of the air depends on atmospheric pressure and temperature which both decrease with height. ASI is celebrated to the ICAO standard atmosphere 29.92 inches of mercury +15 degreases C Vertical speed indicator Rate in feet per minute Change in barometric pressure Static pressure Celebrated leak Lag a. Airspeed Indicator is the ONLY instrument attached to both pitot and static systems b. If **PITOT** system is blocked: - **Airspeed Indicator** - Over reads in a climb, under reads in a descent - **Altimeter** - No effect - **Vertical Speed Indicator** - No effect If **STATIC** system is blocked: - **Airspeed Indicator** - Under reads in a climb, over reads in a descent - **Altimeter** - Freezes at current reading - **Vertical Speed Indicator** - Stays at 0 **Gyroscopic Instruments** - It is a rotor, or spinning wheel, rotating at high speed in a universal mounting, called a gimbal, so its axle can be pointed in any direction. - What Gyroscopic Instruments are used in aircraft? 1. Attitude Indicator 2. Heading Indicator/Directional Gyro 3. Turn Coordinator - Gyroscopic Instruments can be powered by 1 of 3 sources a. Vacuum b. Positive Air Pressure pump c. Battery (electrical source) - Gyroscopic Instruments operate on two principles 1. Inertia a.k.a. Rigidity in Space 2. Precession **Rigidity in Space (Gyroscopic Inertia)** - Tendency of a rotating object to remain in its plane of rotation - This allows the spinning rotor to remain in place regardless of how the gimbal is moved around it **Gyroscopic Precession** - When a force is applied to a spinning gyroscope, it will react as though the force was applied 90^o^ away in the direction of rotation http://www.free-online-private-pilot-ground-school.com/images/gyro-precession.gif Attitude Indicator - Also known as the artificial horizon - Mounted horizontally and spins about its vertical axis - Provides the pilot with an artificial horizon as a means of reference when the natural horizon - It shows the pilot the relationship between the wings and nose of the airplane and the horizon of the earth. - **What gyroscopic property?** - Inertia (rigidity in space) - **Vacuum or electrical?** - Usually vacuum - Some are electrically driven **Attitude Indicator** - Shows the degrees of pitch (nose up/nose down) - Shows wing bank angle **Attitude Indicator Limitations** - **Vacuum?** - Requires at lest 4" of suction for the gyroscope to speed up to the operational speed - **Acceleration Error:** - A sudden acceleration may result in a slight "pitch up" on AI - A sudden deceleration may result in a slight "pitch down" on AI Heading Indicator - Mounted vertically & spins about its horizontal axis. - The spinning gyro wheel is mounted in an inner gimbal ring that is free to turn about the horizontal axis. - The inner ring is, in turn, mounted inside an outer gimbal ring. - The compass rose card on the face of the instrument is attached by a series of gears to the outer gimbal ring. As the airplane turns, the compass card rotates indicating a turn to the left or right. - Must be set to compass heading before flight - **What gyroscopic property?** - Inertia (rigidity in space) - **Vacuum or electrical?** - Usually vacuum May be electrical - **Precession Error** - Friction in the moving parts cause HI to "slow down" - Approximately 3 degrees every 30 minutes - **Apparent Precession (or Drift)** - Gyroscope is fixed in space - Earth rotates underneath, causing an apparent change in position - IMPORTANT: Pilot must check heading indicator against magnetic compass every 15 minutes Turn Coordinator - Operates by precession - Gyro is canted at 35 degrees to sense movements of roll and yaw White arc Asi Pitot static vent blockages Forces that act on the ball on an inclinometer Heading indicator over compass why? Errors with instruments in particular heading instrument Aircraft parked pressure changes Understanding turning pressure nob left is lower and right is higher Compass deviation Knowing about high to low pressure or cold to warm and when you don't adjust your altimeter over reading under reading Aerodynamics understanding the relationship of lift and the components of the lift equation Understand center of pressure center of gravity Overall lift force acts perpendicular to what When airplane is in equilibrium what stages of flight Angle of incidence, cord line, camber, Aspect ration high and low, how it effects induced drag Definition of drag and how speed affects it Angle of attack Boundary layer Stalls critical angle Lift and drag as it reaches a stall Calculate stall speed in a turn 60% bank Wash in wash out Describe rotation of wing tip vortices Know the procedure for following behind a large aircraft landing High and low level airspace How we select cursing altitudes and southern and northern airspace Switching altimeter in airspaces Calculate the pressure altitude 1=100f lower pressure higher altitude high pressure lower altitude Frequency prcedures Controlled and uncontrolled Knowing what you need to have flying in all your airspaces What you have to do if your radio fails in any given airspace Flying through class f airspace cya cyr Boundaries for class b airspace  - Ball indicator (inclinometer) indicates whether the aircraft is coordinated or slipping or skidding - "Step on the Ball" - These instruments are usually electrically powered - Operates by precession - Gyro is mounted vertically and rotates about its horizontal axis - Senses yaw only - Usually powered electrically Rate One" or "Standard" Turn - When the wing tip is aligned with the lower marking or needle is aligned with the left or right symbol (and ball centered) the aircraft is in a "rate one turn" - Rate One Turn: - Aircraft will turn 360 degrees in 2 minutes or 3° per second Angle of Bank and Rate One Turn - Recall: how does angle of bank and airspeed affect rate of turn? - The faster you go, the steeper the angle of bank required to maintain the same rate of turn - IMPORTANT: - The turn coordinator / turn and slip indicator does NOT show the specific angle of bank - How do we figure it out... - We want a rate of turn of 3^o^ per second - The higher the airspeed, the steeper the angle of bank to maintain this rate - Rule of Thumb: - **Required angle of bank = 10% of airspeed + 7** - Airspeed is 100 knots - Angle of bank for rate one turn = 10% of 100 + 7 - 10 + 7 - 17 degrees - Airspeed is 140 knots - 14 + 7 = 21 degrees - In both cases, turn coordinator / turn and slip indicator will indicate rate one turn Angle Of Attack Indicator - AOA indicators measure the angle between the chord line of the wing and the relative wind - As the aircraft wing angle reaches closer to the critical angle of attack, the sensor alerts the pilot of a potential stall - aircraft receive its angle information through a vane protruding into the relative airflow - GA AOA indicators rely on pitot and static information sent to an onboard computer How It Works: Angle of Attack Indicator Mach Indicator - A mach indicator provides a continuous indication of the ratio of an airplane\'s airspeed to the local speed of sound. - The mach indicator displays a fraction of the speed of sound. - Ex. 0.5 = half the speed of sound - 1.0 = speed of sound - Connected to both pitot and static sources - Speed of sound is dependent on the ambient temperature. - The warmer the temperature the fast the speed of sound - The colder the temperature the slower the speed of sound. Electronic Flight Instrument System (EFIS - An Electronic Flight Instrument System (EFIS) is a flight deck instrument display system in which the display technology used is electronic rather than electromechanical or mechanic - Modern EFIS will consist of two screens to display a range of instrumentation and information 1. Primary Flight Display (PFD) 2. Multi-Function Display (MFD) - The Primary Flight Display will show your standard 6 instruments a. Airspeed Indicator b. Attitude Indicator c. Altimeter d. Turn Coordinator e. Heading Indicator f. Vertical Speed Indicator - Some PFD can display other information such as AOA, traffic, and Nav/Com data - The Multi-Function Display will show other information such as: - Engine parameters - Moving maps - Terrain data - Weather data The Earth's Magnetism - The earth is a magnet - North and South magnetic pole - Creates a magnetic field that surrounds the earth - A compasses needle will be influenced by this magnetic field Compass Errors - Subject to the following errors: - Deviation - Northerly Turning Error - Acceleration Error Deviation - Compass is magnetic - Influenced by metal and electrical fields in the airplane - May not read exactly correctly depending on the direction the aircraft is pointing - Maintenance checks this every 12 months by calibrating the compass - Called "swinging" the compass Compass Calibration ("Swinging the Compass") - Conducted by maintenance personnel - Compass indication is compared to a known heading - deviation noted - "Known heading" provided by compass rose painted on airport apron or by highly accurate hand compass - Adjusting screws on compass to minimize the error - The angle through which the compass needle is deflected from the magnetic meridian is called deviation. Magnetic Dip - Earth's lines of force - At higher latitudes - Affect of centre of gravity of the system  Northerly Turning Error - Caused by centripetal and centrifugal forces - Most apparent on North and South headings - Commencing a turn from a heading of North = lag - Commencing a turn from a heading of South = lead Compass Errors -- Acceleration - When flying in an **Easterly** or **Westerly** heading, if the aircraft accelerates or decelerates, the compass will read incorrectly momentarily - **Acceleration Error (ANDS):** - **AN** (Accelerate-North) = Compass momentarily turns to the North - **DS** (Decelerate-South) = Compass momentarily turns to the South - **Canadian Airspace is divided in seven different classes** - **Each class of airspace has its own individual rules of access, flight regulations & ATC requirements** - **Only IFR flight is permitted.** - **Includes all controlled high level airspace between 18,000 feet ASL and FL600 inclusive.** - **It includes the Southern Control Area, Northern Control Area and Arctic Control Area.** - **Must use Standard Pressure Region procedures.** - **Require ATC Clearance to enter** - **Above FL600 is class E** - **An operational need exists to provide air traffic control to IFR aircraft and to control VFR aircraft.** - **All aircraft are subject to ATC separation** - **Includes all controlled low level airspace between 12,500 feet up to but not including 18,000 feet ASL.** - **Control zones and associated terminal control areas may also be classified as Class B.** - **A VFR flight plan must be filed to enter and two-way radio communication is required.** - **Controlled airspace wherein both IFR and VFR flights are permitted. VFR pilots must be cleared by ATC to enter.** - **ATC separation is provided between IFR traffic and as necessary between IFR and VFR traffic and upon request, between VFR traffic.** - **Terminal control areas and associated control zones may be classified as Class C.** - **Class C airspace becomes Class E when the ATC unit is not in operation.** - **Must have two-way radio communication and a Mode C transponder** - **Example: London's Control Zone** - **Controlled airspace wherein which both IFR and VFR flights are permitted.** - **ATC separation is provided for IFR traffic only.** - **Two-way radio communication is required before entering.** - **Terminal control areas and associated control zones may be classified as Class D airspace.** - **Class D airspace becomes Class E when the ATC unit it not in operation.** - **An operational need exists for controlled airspace but the requirements for Class A, B, C or D are not met.** - **Traffic separation is provided only to IFR flights.** - **No special requirements for VFR traffic.** - **Generally begins at 2,200 feet AGL, and extends up to, but not including, 12,500 feet ASL unless otherwise noted.** - **May start lower as indicated on a chart** - **Class E Airspace** - **Airspace of defined dimensions which activities must be confined because of their nature and within which limitations may be imposed on aircraft which are not part of those activities.** - **Restrictions may be permanent or temporary.** - **Classified as either** a. **ADVISORY** b. **RESTRICTED** - **CYA** - **Yes, but advised not to** - **CYR** - **No, unless you have permission from the user agency** - **Airspace that has not been designated Class A, B, C, D, E or F and within which ATC has neither the authority nor the responsibility for exercising control over air traffic.** - **Uncontrolled airspace** - **ATS units do provide flight information and alerting services** - **Airspace underneath class E airspace** - **Airspace below 18,000'** - **Areas where control is not required (little traffic)** - **Shown on a VFR map with a "Controlled Area Boundary"** - **The solid line side is the controlled side** FGU.4-14.jpg MID TERM EXAM White arc Asi Pitot static vent blockages Forces that act on the ball on an inclinometer Heading indicator over compass why? Errors with instruments in particular heading instrument Aircraft parked pressure changes Understanding turning pressure nob left is lower and right is higher Compass deviation Knowing about high to low pressure or cold to warm and when you don't adjust your altimeter over reading under reading Aerodynamics understanding the relationship of lift and the components of the lift equation Understand center of pressure center of gravity Overall lift force acts perpendicular to what When airplane is in equilibrium what stages of flight Angle of incidence, cord line, camber, Aspect ration high and low, how it effects induced drag Definition of drag and how speed affects it Angle of attack Boundary layer Stalls critical angle Lift and drag as it reaches a stall Calculate stall speed in a turn 60% bank Wash in wash out Describe rotation of wing tip vortices Know the procedure for following behind a large aircraft landing High and low level airspace How we select cursing altitudes and southern and northern airspace Switching altimeter in airspaces Calculate the pressure altitude 1=100f lower pressure higher altitude high pressure lower altitude Frequency prcedures Controlled and uncontrolled Knowing what you need to have flying in all your airspaces What you have to do if your radio fails in any given airspace Flying through class f airspace cya cyr Boundaries for class b airspace