AE-705: Introduction to Flight Takeoff & Landing by Hemashree Kakar Mechanical Engineering Department RTU Kota AE-705 Introduction to Flight Lecture-18 Capsule-09
Take-off and Landing AE-705 Introduction to Flight Lecture-18 Capsule-09
TAKE-OFF AE-705 Introduction to Flight Lecture-18 Capsule-09
AE-705 Introduction to Flight Lecture-18 Capsule-09
For an aircraft to lift off the ground Lift > Weight Aircraft velocity > Stalling Velocity Lift-off Velocity (V LO ) Usually, V LO > 1.15 V stall AE-705 Introduction to Flight Lecture-18 Capsule-09
PHASES DURING TAKE-OFF AE-705 Introduction to Flight Lecture-18 Capsule-09
Phases Ground Screen Height (15 m) Transition Climb run L V A T D μ R Climb W Ground run Transition Take-off distance V A > V TO A = Nose wheel lift off speed ≈ 0.85 V TO V AE-705 Introduction to Flight Lecture-18 Capsule-09
Estimation of take-off performance The take-off distance(s) and the time (t) taken for it Distance covered and Distance covered and Distance covered and time taken during ground time taken during time taken during climb run transition phase phase AE-705 Introduction to Flight Lecture-18 Capsule-09
Distance covered and time taken during ground run L R T D μ R W and time taken (t 1 ) is given by : AE-705 Introduction to Flight Lecture-18 Capsule-09
Various speeds during Take-off Run V 2 V mu V LO V r V = 0 V mc V 1 V s 15 m AE-705 Introduction to Flight Lecture-18 Capsule-09
V s = Stall Speed speed in steady level flight at W = W TO C L = C LTO Flaps Configuration of the Slats Depends upon: plane Lift-control devices AE-705 Introduction to Flight Lecture-18 Capsule-09
V mcg V mc : Minimum control speed V mca Starboard engine fails Yaws to the starboard Apply port side rudder Below a certain speed there simply is not enough aerodynamic force generated by the rudder to produce the correcting yaw. This velocity is called V mc. Aircraft balanced Counter moment produced AE-705 Introduction to Flight Lecture-18 Capsule-09
V mu : Minimum unstick speed Speed which defines the point at which the aircraft could take off if the maximum possible rotation angle were reached. This maximum angle would occur if the tail of the plane were to actually scrape the ground. V mu AE-705 Introduction to Flight Lecture-18 Capsule-09
Distance covered (s 2 ) and time (t 2 ) taken during transition phase Work done by engine = Work done in overcoming drag + Increase in KE Time taken (t 2 ) in transition AE-705 Introduction to Flight Lecture-18 Capsule-09
The height attained during transition phase Hint: can be obtained by treating the flight path as part of a circle AE-705 Introduction to Flight Lecture-18 Capsule-09
Distance covered (s 3 ) and time (t 3 ) taken during climb phase Screen Height (15 m) Climb Time taken (t 3 ) in climb phase Take-off distance = s 1 + s 2 + s 3 Take-off time = t 1 + t 2 + t 3 AE-705 Introduction to Flight Lecture-18 Capsule-09
Take-off run as accelerating force Acceleration force as Thrust 1) Afterburner 2) Rocket Assisted Take-off 3) Catapult Takeoff AE-705 Introduction to Flight Lecture-18 Capsule-09
Needs longer Apply brakes and stop the plane runway Or take-off distance Continue to fly with one engine increase inoperative and take-off AE-705 Introduction to Flight Lecture-18 Capsule-09
The speed of aircraft in this condition is called Decision Speed (s stop ) decision speed = (s stop ) one engine failure s stop : Distance taken to stop AE-705 Introduction to Flight Lecture-18 Capsule-09
The strength of the wing- Aircraft flying close to tip vortices decreases the ground The downwash and hence induced drag are reduced h = height of the wing above the ground b = wingspan Ground Effect AE-705 Introduction to Flight Lecture-18 Capsule-09
AE-705 Introduction to Flight Lecture-18 Capsule-09
Phases of Landing Final approach Steady descent Flare Flight path tends to horizontal Float Main wheel touches the ground (V y ≤ 4 m/s) Roll Nose wheel lowers to touch the ground Brakes not applied Screen Height (15 m) Ground run Decelerates to come to halt Brakes applied V = 0 V = V L A Touch down V = V T = 0.9 V A D μ R Roll Flare Final W approach Ground run (s g ) Float Airborne distance(s) Landing distance (s 1 ) AE-705 Introduction to Flight Lecture-18 Capsule-09
Estimation of Landing Distance Braking System Acceleration (a) -1.22 m/s 2 Simple -1.52 m/s 2 Average -1.83m/s 2 Modern -2.13 to 3.0 m/s 2 Airplanes with modern braking system and reverse thrust on reverse pitch propellers AE-705 Introduction to Flight Lecture-18 Capsule-09
LD as wing loading (W/S) LD as wing loading (W/S) LD as wing density ( ρ ) LD as wing density ( ρ ) AE-705 Introduction to Flight Lecture-18 Capsule-09
How to decrease landing distance ? Reverse thrust Arresting gear Drag parachute Spoilers AE-705 Introduction to Flight Lecture-18 Capsule-09
FLAP SETTINGS DURING TAKE-OFF AND LANDING AE-705 Introduction to Flight Lecture-18 Capsule-09
High C Lmax decreases Take-off run and Landing distance Take-off C LTO C D s TO C LTO V TO s TO Optimum C LTO and corresponding flap setting Lowest Take-off run AE-705 Introduction to Flight Lecture-18 Capsule-09
Landing C LL C D s TO C LL V A s TO C LL = C Lmax and corresponding flap setting Lowest Take-off run AE-705 Introduction to Flight Lecture-18 Capsule-09
(C Lmax ) TO = 0.8 (C Lmax ) L Takeoff Flap setting is lower than Landing Flap setting Take off Flap: 20 - 40 deg Landing Flap: 40 – 60 deg AE-705 Introduction to Flight Lecture-18 Capsule-09
Just before final approach to land HOLDING STACKS @ AIRPORT AE-705 Introduction to Flight Lecture-18 Capsule-09
HOLDING STACKS Typical Arrival patterns • Busy airports / times • Extra Fuel carried • Regulatory requirement • 60 to 75 minutes • ~ 800 km Usual Actual APPROACH PATHS Massive changes needed Massive changes needed • • Usually due to weather Usually due to weather • • Extra Fuel carried One Example • • Extra Fuel carried Navigational Reserves • • Navigational Reserves • AE-705 Introduction to Flight Lecture-18 Capsule-09
Use of Holding Stacks during bad weather AE-705 Introduction to Flight Lecture-18 Capsule-09
Most difficult and dangerous flight operations ! X-WIND TAKEOFF & LANDING AE-705 Introduction to Flight Lecture-18 Capsule-09
with no wind No crosswind at all with an exact headwind with an exact tailwind In all other conditions there is a cross wind AE-705 Introduction to Flight Lecture-18 Capsule-09
Let angle between wind direction and runway = 70° Let wind velocity = 30 Knots Crosswind = 28 Knots Ignore the zigzag pattern of wind velocity (red) http://www.experimentalaircraft.info/flight-planning/aircraft-performance-41.php AE-705 Introduction to Flight Lecture-18 Capsule-09
Vertical Take-off and Landing (VTOL) Vertical lift is achieved by counter rotating propeller blades housed inside a duct. Mainly used in Military Aircraft AE-705 Introduction to Flight Lecture-18 Capsule-09
low fuel efficiency slow safety speed limited application of VTOL in personal aircraft high cost of operation high noise per levels passenger mile AE-705 Introduction to Flight Lecture-18 Capsule-09
Look at this and imagine what would happen if one of the engines suddenly stopped working Airbus A350 https://www.quora.com/Why-arent-VTOL-technologies-used-in-airliners AE-705 Introduction to Flight Lecture-18 Capsule-09
Now look at this and imagine what would happen if one of the engines suddenly stopped working Bell Boeing V-22 Osprey (VTOL) https://www.quora.com/Why-arent-VTOL-technologies-used-in-airliners AE-705 Introduction to Flight Lecture-18 Capsule-09
Future Scope AE-705 Introduction to Flight Lecture-18 Capsule-09
Magnetic Levitation Area of benefit Values Weight 9.3% saving for take-off weight, 18.1% for total fuel weight Fuel consumption 79.6% reduction for take-off, 8.2% for the en- route, 60% for the LTO Emissions at the airport region decreasing by 58% CO2, 60% NOX for LTO Noise at the airport region in reduction by 64% for take-off, 19.7% for landing terms of area affected Sustainability increasing by 8.75% Cost-benefit- total cost savings total cost savings per cycle 1.579,26 € per cycle http://www.gabriel-project.eu/ AE-705 Introduction to Flight Lecture-18 Capsule-09
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