Project-1: Powertrain for aircraft in runways

Part-A

1. The aircraft gross weight is the total aircraft weight at any moment during the flight or ground operation.

For each flight, different weights are taken into account for several reasons.

Manufacturer's empty weight (MEW)
It is the weight of the aircraft "as built" and includes the weight of the structure, power plant, furnishings, installations, systems and other equipment that are considered an integral part of an aircraft. This excludes any baggage, passengers, or usable fuel.

Zero-fuel weight (ZFW)

This is the total weight of the airplane excluding the total weight of the usable fuel on board. As a flight progresses and fuel is consumed, the total weight of the airplane reduces, but the ZFW remains constant.

Operating empty weight (OEW)

It is the basic weight of an aircraft including the crew, all fluids necessary for operation such as engine oil, engine coolant, water, unusable fuel and all operator items and equipment required for flight but excluding usable fuel and the payload.

Payload

It is the carrying capacity of an aircraft. It includes cargo, people, extra fuel. In the case of a commercial airliner, it may refer only to revenue-generating cargo or paying passengers.

Maximum takeoff weight (MTOW)

This is the maximum weight at which the pilot of the aircraft is allowed to attempt to take off.

Regulated takeoff weight (RTOW)

Depending on different factors (e.g. flap setting, altitude, air temperature, length of runway), RTOW or maximum permissible takeoff weight varies for each takeoff. It can never be higher than MTOW.

Maximum landing weight (MLW)

This maximum weight at which an aircraft is permitted to land.

The following image depicts take-off weight components.

Type	MTOW [kg]	MLW [tonnes]
Antonov An-225	640,000	591.7
Scaled Composites Model 351 Stratolaunch	589,670
Airbus A380-800[1][2][3]	575,000	394
Boeing 747-8F	447,700	346.091
Boeing 747-8	443,613	306.175
Boeing 747-400ER	412,770	295.742
Antonov An-124-100M	405,060	330
Boeing 747-400	396,900	295.742
Lockheed C-5 Galaxy[4][5][6]	381,000	288.417
Boeing 747-200[7]	377,840	285.7
Boeing 747-300[7]	377,840	260.32
Airbus A340-500[8]	371,950	240
Airbus A340-600[8]	367,400	256
Boeing 777F	347,800	260.816
Boeing 777-300ER	351,800	251.29
Boeing 777-200LR	347,450	223.168
Boeing 747-100[7]	340,200	265.3
Airbus A350-1000	308,000	233.5
Boeing 777-300	299,370	237.683
Boeing 777-200ER	297,550	213
Airbus A340-300[8][9]	276,700	190
McDonnell Douglas MD-11	273,300	185
Airbus A350-900	270,000	175
Ilyushin Il-96M	270,000	195.04
McDonnell Douglas DC-10	256,280	183
Boeing 787-9[10]	254,000	192.777
Boeing 787-10[10]	254,000	201.849
Airbus A340-200[8][11]	253,500	181
Airbus A330-900	251,000	191
Ilyushin IL-96-300	250,000	175
Airbus A330-300[12][13]	242,000	185
Airbus A330-200[12][13]	242,000	180
Lockheed L-1011-500	231,300	166.92
Boeing 787-8[10]	228,000	172.365
Lockheed L-1011-200	211,400
Ilyushin IL-86	208,000	175
Boeing 767-400ER	204,000	158.758
Airbus A300-600R[14]	192,000	140
Boeing 767-300ER	187,000	136.08
Concorde	185,000	111.1
Airbus A300-600[14]	163,000	138
Boeing 767-300	159,000	136.078
Airbus A310-300[14]	157,000	124
Vickers VC10	152,000	151.9
Boeing 707-320B[15]	151,000	97.5
Boeing 707-320C[15]	151,000	112.1
Douglas DC-8-61	147,000
Airbus A310-200[14]	142,000	123
Airbus A400M	141,000	122
Douglas DC-8-32	140,000
Douglas DC-8-51	125,000
Boeing 757-300	124,000	101.6
Boeing 707-120B[15]	117,000	86.3
Boeing 757-200	116,000	89.9
Boeing 720B[16]	106,000	79.5
Boeing 720[16]	104,000	79.5
Tupolev Tu-154M	104,000	80
Tupolev Tu-204SM	104,000	87.5
Convair 880	87,500
Boeing 737-900	85,000	66.36
Boeing 737-900ER	85,000	71.35
Boeing 727-200 Advanced[17]	84,000	70.1
Airbus A321-100[18]	83,000	77.8
Boeing 737-800	79,000	65.32
Boeing 727-200[17]	78,000	68.1
McDonnell-Douglas MD-83	73,000	63.28
Boeing 727-100[17]	72,500	62.4
Boeing 727-100C[17]	72,500	62.4
McDonnell-Douglas MD-90-30	71,000	64.41
de Havilland Comet 4	70,700
Boeing 737-700	70,000	58.06
Airbus A320-100[18]	68,000	66
Boeing 737-400	68,000	54.9
de Havilland Comet 3	68,000
Boeing 377	67,000
Boeing 737-600	66,000	54.66
Airbus A220-300	65,000	57.61
Hawker Siddeley Trident 2E	65,000
Airbus A319[18]	64,000	62.5
Boeing 737-300	63,000	51.7
Boeing 737-500	60,000	49.9
Airbus A220-100	59,000	50.8
Airbus A318[18]	59,000	57.5
Boeing 717-200HGW	55,000	47.174
Douglas DC-7	55,000
de Havilland Comet 2	54,000
Boeing 717-200BGW	50,000	46.265
de Havilland Comet 1	50,000
Douglas DC-6A	48,600
Douglas DC-6B	48,500
Embraer 190[19]	48,000	43
Caravelle III	46,000
Fokker 100	46,000	39.95
Douglas DC-6	44,000
Avro RJ-85	42,000	36.74
Handley Page Hermes	39,000
Embraer 175[20]	37,500	32.8
Bombardier CRJ900[21]	36,500	33.345
Embraer 170[22]	36,000	32.8
Bombardier CRJ700	33,000	30.39
Douglas DC-4	33,000
Vickers Viscount 800	30,400
Bombardier Q400	28,000	28.01
Bombardier CRJ200	23,000	21.319
ATR 72-600	22,800	22.35
Saab 2000	22,800	21.5
Embraer ERJ 145	22,000	19.3
ATR 42-500	18,600	18.3
Saab 340	13,150	12.930
Embraer 120 Brasilia	11,500	11.25
BAe Jetstream 41	10,890	10.57
Learjet 75[23]	9,752	8.709
Pilatus PC-24[24]	8,300	7.665
Embraer Phenom 300[25]	8,150	7.65
Beechcraft 1900D	7,765	7.605
Cessna Citation CJ4[26]	7,761	7.103
de Havilland Hercules	7,000
Embraer Phenom 100	4,800	4.43

2.Is there any difference between ground speed and air speed?

Yes. ground speed and air speed are different.

Airspeed or real airspeed is an airplane's speed relative to the air it is flying in, whereas ground speed is an airplane's speed relative to the Earth's surface.Airspeed is also the speed at which the air is flowing around the aircraft’s wings.

Ground speed, on the other hand, is the aircraft’s speed relative to the ground. It is horizontal rather than vertical speed. Airspeed determines whether there is enough airflow around an aircraft to make it fly and ground speed is what determines how fast an aircraft get to its destination.

3.

The thrust produced when an aircraft's engine starts up can easily damage the airport terminal, nearby ground vehicles, the jetway, luggage, and most critically, ground employees. When pulling a huge aircraft, it's especially crucial to limit engine use because of how dangerously harmful their more potent thrust capabilities might be. Engine power can readily launch any loose objects into the air, convert even the smallest dust particles into dangerous projectiles, and produce debris that can harm multi-million dollar engines. In addition, aircraft engines use a lot of fuel and produce a lot of noise that can be dangerous for those on the ground. Therefore, using a pushback tug rather than operating the engines is more cost-effective and secure.

4.

Pushback, in the context of aviation, is an airport process in which an aircraft is propelled by external force away from an airport gate. Pushback tractors or tugs are specialised, low-profile vehicles used to perform pushbacks.

Although many aeroplanes are capable of using reverese thrust to propel themselves backwards on the ground, the jetblast or propwash may harm the terminal structure or its equipment. Engine damage can also result from engines that are close to the ground blowing sand and other debris ahead before being sucked into the engine. Therefore, pushing the plane back is the technique to get it out from under the gate.

In order to facilitate ground movement on taxiways, pushbacks at busy aerodromes are typically subject to ground control clearance. When the pushback is ready to begin, the pilot communicates with the tractor driver. Near the nose gear, a headset might be connected for communication.The pushback tractor driver controls the aircraft's steering instead of the pilots because they are unable to see what is behind the aircraft. The nose gear may temporarily be disconnected from the aircraft's usual steering mechanism by installing a bypass pin into it, depending on the kind of aircraft and airline policy.

The towbar is disconnected and any bypass pins are taken out when the pushback is finished. To demonstrate to the pilots that the bypass pin has been removed, the ground handler will display it to them. The aeroplane can then taxi ahead using its own power after the pushback is finished.

5.

TAKE OFF POWER

The aircraft transitions from being on the ground on a runway to flying in the air during takeoff. The aeroplane is stopped after taxing up to the runway's beginning. To look for engine-related issues, the engines are run at full power. The aircraft is then quickly accelerated until the required speed for takeoff is reached before the pilot releases the brakes. The takeoff speed varies according to the aircraft's weight, air density, and configuration. The distance from sea level and temperature of the atmosphere affect the air density. If the plane must take off, it must do so at the required takeoff speed, which is also influenced by the runway's length and slope.

The speed of takeoff varies with the air's movement. Because there is more air flowing over the wings when there is a headwind, the takeoff speed is substantially lower. The aeroplanes so typically take off against the wind. Typically, side wind is not desirable as it might affect the aircraft's stability. Jetliners typically take off at speeds between 240 and 285 km/h, and this speed is directly inversely proportional to the weight of the aircraft. Some aeroplanes struggle to produce enough lift during takeoff.

TYRE DESIGN

A tyre is a crucial element of an aircraft's safety system. Tires act as a cushion and assist in absorbing the impact of landing. Additionally, it gives the aircraft the traction it needs to halt and brake.The aircraft is built with the ability to resist very heavy weights during takeoff, landing, taxing, and parking. Due to the necessity for a more equitable distribution of weight, the number of wheels needed for an aircraft rises as its weight does.

ROLLING RESISTANCE

Rolling resistance is the force that resists the motion when the body rolls on the surface.

It is represented by,

F_rr = μ_r m g

Where ,

F_rr = rolling resistance force (N)

μ_r = coefficient of rolling resistance

m = Total mass of the vehicle (kg)

g = Acceleration due to gravity (m/s²)

TYRE PRESSURE

The design of aircraft tyres allows them to sustain severe loads for brief periods of time. Because the weight of the plane needs to be distributed more equally, the number of tyres needed for an aircraft rises as it gets heavier. The thread pattern of the aircraft tyre is made to be both effective for braking and to help with stability in strong crosswinds.

If the full amount of braking force is used during an emergency landing or aborted takeoff, tyres may become overheated. The fuses offer a safer failure mode that prevents the explosion of tyres by carefully deflating them, hence reducing damage to the aircraft and other objects. Up to 200 psi is the maximum operating pressure for aircraft tyres.

BRAKING FORCES WHEN LANDING

By converting kinetic energy into thermal energy through friction between spinning and stationary discs found in braking assemblies in the wheels, aircraft brakes assist in bringing a moving craft to a halt. These brakes provide crucial stopping friction during landing, allowing the aircraft to come to a halt within the runway's length. The aircraft brakes assist in stopping the vehicle before takeoff in the event of any technical difficulties.

By delivering varying degrees of braking power to the left and right-side brakes, aircraft brakes also stop motion of the aircraft when it is parked, control speed during taxing, and can assist in guiding the aircraft on the ground. Other braking systems, like as thrust reversers, air brakes, and spoilers, cooperate with aircraft brakes to stop a moving object. Thrust reversers are surfaces that are positioned in the course of the engine's jet blasts in order to divert the thrust in a way that complements the motion of the aircraft.

Part B:

6.A. With necessary assumptions, calculate the force and power required to push / pull an aircraft by a towing vehicle.

A towing vehicle is necessary to push/pull the aeroplane from the terminal gate. Towing vehicles need a lot of torque to draw or push an aircraft.

To determine the amount of force and power the towing vehicle needs to push or pull the aircraft, Rolling resistance, Acceleration force and Aerodynamic drag forces are taken into account.

B. Develop the model for the calculated force and power using Simulink.

7. A.

AIRCRAFT PARAMETERS

PARAMETERS	VALUES	UNITS
Mass of the aircraft	48500	kg
Coefficient of rolling resistance	0.03	--
Frontal area of the aircraft	85	M2
Final velocity of the aircraft	3	m/s
Initial velocity of the aircraft	0	m/s
Coefficient of drag of an aircraft	0.15	--
Acceleration time of the Towing vehicle	10	Seconds

TOWING VEHICLE PARAMETERS

PARAMETERS	VALUES	UNITS
Mass of the Towing vehicle	8000	kg
Coefficient of rolling resistance	0.013	--
Frontal area of the Towing vehicle	8	M2
Final velocity of the Towing vehicle	3	m/s
Initial velocity of the Towing vehicle	0	m/s
Coefficient of drag of the Towing vehicle	0.60	--
Acceleration of the Towing vehicle	10	seconds
Gear ratio	10

The towing vehicle must have a total power output of 97.02 KW and a total tractive force of 32341 N to push or pull the aircraft. The towing vehicle's necessary torque is calculated as

Tt = Ft _* r /G = 32341* 0.4 / 10= 1293.64 Nm

A motor is chosen based on its power rating, and a battery is needed depending on the amount of energy required and the duty cycle range to control the aircraft speed from zero to the highest.

The TECO IE2 electric induction motor is chosen because it meets the vehicle's requirements for power output and torque with a 110 KW output and 1420 Nm of torque at full load.

MOTOR SPECIFICATIONS

Output power – 110 KW, 150 hp

Full load speed – 740 rpm

Full load Efficiency – 94.5%

Full load current – 210A

Full load Torque – 1420 Nm

Rated voltage – 400V/50 Hz

The rated voltage is 400V and the current is assumed to be 280A. So, the input power of the motor is calculated as

P_{input =} 400 *280= 112000W=112kW

Poutput=97.02kW

d=97.02/112=86.6%

To calculate the energy required from battery pack for 10 minutes(10*60)

E = P_o * t= 97.02 * 600= 58212kJ

E = 58212kJ/3600= 16.17KWH

Powertrain model:

Block diagram:

B.

Calculation of force and power required to push/pull an aircraft
	Aircraft	Towing vehicle
Mass	48500	8000
Coefficient of rolling resistance	0.03	0.013
Acceleration due to gravity(ms-2)	9.81	9.81
Frontal area of an aircraft(m2)	85	8
Final velocity of the aircraft(m/s)	3	3
Initial velocity of the aircraft(m/s)	0	0
Coefficient of drag of an aircraft	0.15	0.6
Density of air(kg/m3)	1.225	1.225
Acceleration time (s)	10	10
ROLLING RESISTANCE FORCE	14273.55	1020.24
ACCELERATION FORCE	14550	2400
AERODYNAMIC DRAG FORCE	70.284375	26.46
Total Tractive force(N)	32340.53438
Power Required to push/Pull(kW)	97.02160313

Excel calculation file is attached for reference.