Project-1: Powertrain for aircraft in runways

Part A

1. Total weight of various types of aircrafts

Weights of different components computed to form the TakeOff Weight of Aircraft is shown in the above image. Various Aircrafts according to Maximum Takeoff Weight is shown in below table.

Type	MTOW [kg]	ICAO category
Embraer Phenom 100	4800	Light
de Havilland Hercules	7000	Medium
Cessna Citation CJ4	7761	Medium
Embraer ERJ 145	22000	Medium
ATR 72-600	22800	Medium
Bombardier Q400	28000	Medium
Bombardier CRJ700	33000	Medium
Douglas DC-4	33000	Medium
Bombardier CRJ900	36500	Medium
Douglas DC-6	44000	Medium
Embraer 190	48000	Medium
Douglas DC-6A	48600	Medium
Boeing 717-200HGW	55000	Medium
Airbus A220-100	59000	Medium
Airbus A220-300	65000	Medium
Boeing 737-600	66000	Medium
Boeing 377	67000	Medium
Airbus A320-100	68000	Medium
Boeing 737-700	70000	Medium
McDonnell-Douglas MD-83	73000	Medium
Boeing 727-200	78000	Medium
Airbus A321-100	83000	Medium
Boeing 737-900	85000	Medium
Boeing 720	104000	Medium
Boeing 707-120B	117000	Medium
Boeing 757-300	124000	Medium
Douglas DC-8-51	125000	Medium
Douglas DC-8-32	140000	Heavy
Airbus A400M	141000	Heavy
Airbus A310-200	142000	Heavy
Douglas DC-8-61	147000	Heavy
Boeing 707-320B	151000	Heavy
Airbus A310-300	157000	Heavy
Boeing 767-300	159000	Heavy
Airbus A300-600	163000	Heavy
Concorde	185000	Heavy
Boeing 767-300ER	187000	Heavy
Airbus A300-600R	192000	Heavy
Boeing 767-400ER	204000	Heavy
Lockheed L-1011-500	231300	Heavy
Airbus A330-300	242000	Heavy
Airbus A330-900	251000	Heavy
Boeing 787-9	254000	Heavy
McDonnell Douglas DC-10	256280	Heavy
Airbus A350-900	270000	Heavy
McDonnell Douglas MD-11	273300	Heavy
Airbus A340-300	276700	Heavy
Airbus A350-1000	308000	Heavy
Boeing 777-200LR	347450	Heavy
Boeing 777F	347800	Heavy
Boeing 777-300ER	351800	Heavy
Airbus A340-500	371950	Heavy
Boeing 747-300	377840	Heavy
Lockheed C-5 Galaxy	381000	Heavy
Boeing 747-400	396900	Heavy
Antonov An-124-100M	405060	Heavy
Boeing 747-400ER	412770	Heavy
Boeing 747-8	443613	Heavy
Boeing 747-8F	447700	Heavy
Airbus A380-800	575000	Heavy
Antonov An-225	640000	Heavy

2. Difference between ground speed and air speed

The aeroplane travels respect to a reference point at ground speed for a chosen ground reference point. The wind speed determines how far the air flows in relation to a reference point chosen on the ground. Both the speed has a magnitude as well as a direction. The airspeed, or relative velocity between the object and the air, is a crucial factor in the production of lift. From a ground location, airspeed cannot be determined directly; instead, it must be calculated out from ground speed and the wind speed.

Airspeed = Ground Speed - Wind Speed

3. Why is it not recommended to use aircraft engine power to move it on the ground at Airport?

• The thrust produced when an aircraft's engine starts up can easily damage the airport terminal, nearby ground vehicles, the jetbridge, luggage, and most critically, ground employees.
• Aircraft pushback and towing tugs are also used to facilitate general maintenance by ground staff.
• The flight deck's poor rear visibility forces pilots to occasionally rely on aircraft towing equipment for ground pushback.
• Without the aid of aircraft towing equipment, the majority of aircraft typically cannot travel backward. Pushback tugs are the sole option when pulling aircraft into hangars or away from the terminal building because aeroplanes are not constructed with a reverse option that pilots may employ for backward movement.

4. How an aircraft is pushed to runway when its ready to take off?

Pushback: occurs when tractors or tugs are used to push an airplane rearward away from the airport gate. A tug for an airplane will pull up just in front of the nose wheel as we get closer to takeoff. The tug may be a "wheel-lift" tug or it could be directly connected to the plane's nose gear with a tow bar. These tugs support the nose gear while lifting it up and then moving the aircraft. As a result, the tug driver has control over the plane's pushback direction.

Electric motors fitted to the aircraft's landing gear and pilot-controlled tugs are two examples of the new taxi technologies that are emerging. Both claim to lessen airport noise and conserve fuel.

5. Take off power, tyre design, rolling resistance, tyre pressure, brake forces when landing.

Take-off Power: The amount of power an engine is permitted to produce for a brief period of time during take-off is known as take-off power. Take-off power is typically only used for up to 5 minutes with reciprocating engines and up to 2.5 minutes with gas turbine engines. This could not always be the situation. The engine thrust is adjusted to a high "take-off power" level during take-off in order to place the aircraft to a safe height away from terrain and impediments, and the aircraft attitude is pitched up to maintain a certain speed.

Tyre Design: A plane's tyres are made to resist incredibly large weights during takeoff, landing, taxing, and parking. The number of wheels necessary for aircraft grows with the weight of the aircraft, since the weight of the airplane has to be distributed more equally. It is not required to carry a weight for an extended length of time while operating continuously, unlike a car or truck tyre. An aviation tyre, on the other hand, can operate at high speeds for a brief period of time when necessary and can also bear the heavy impact loads of landings. The tyre is made using carcass plies. They are also known as casing plies.

When retracted via landing gear, aircraft tyres must have enough room to accommodate tyre expansion and have a speed and load rating that has been certified. Tyre growth is an increase in tyre size brought on by high-speed centrifugal forces.

Rolling Resistace: Rolling resistance is the amount of effort per unit of vehicle weight needed to drive the vehicle at a steady, slow speed on level ground with little to no aerodynamic drag and without the use of any traction forces or brakes. The force restraining motion when a body rolls on a surface is known as rolling resistance, often referred to as rolling friction or rolling drag. It is mostly brought about by non-elastic effects, which means that not all of the energy required for the deformation (or movement) of the wheel, roadbed, etc., is restored when the pressure is released.

Tyre Pressure: An aviation tyre is made to support very large weights for a brief period of time. Nitrogen is typically used to inflate aircraft tyres in order to reduce the amount of expansion and contraction caused by the rapid variations in pressure and temperature that occur when the aircraft is in flight. Airliner aeroplane tyres can withstand pressures of up to 800 psi before exploding, according to tests. The typical operating pressure for aircraft tyres is high, up to 200 psi for commercial airliners and much more for business jets. Each of the twelve primary tyres of the Boeing 777-300ER weighs 120 kg, has a diameter of 134 cm (53 in), is inflated to 220 psi, and is replaced every 300 cycles while the brakes are replaced every 2000 cycles.

Brake forces when landing: By turning kinetic energy into thermal energy through friction between spinning and stationary discs found in braking assemblies in the wheels, aeroplane brakes are able to halt moving aircraft. This essential stopping function is provided by brakes during landings so that aircraft may stop within the runway's length. Moreover, they halt planes when a takeoff attempt is refused. 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 engine blast's path to reroute propulsive thrust in the opposite direction from the aircraft's motion.

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

Mass of Aircraft (`M_1`) = 5,75,000kg (Airbus A380)

Mass of Towing Vehicle (`M_2`) = 60,000kg (TLD TMX- 550)

Coefficient of rolling resistance of Aircraft (`mu_1`) = 0.04

Coefficient of rolling resistance of Towing Vehicle (`mu_2`) = 0.012

Frontal Area of Aircraft (`A_1`) = 110 `m^2`

Frontal Area of Towing Vehicle (`A_2`) = 5.23 `m^2`

Drag coefficient of Aircraft `C_(d1)`= 0.12

Drag coefficient of Towing Vehicle `C_(d2)`= 0.2

Air Density = 1.25 `(kg)/m^3`

Acceleration due to gravity (g) = 9.81 `m/s^2`

Speed of Tow/ Aircraft = 3kmph = 0.83mps

Rolling Resistance Force, Frr = `mu`M g

Rolling Resistance Force of Aircraft, `Frr_1 = mu_1 M_1 g`

= 0.04 x 575000 x 9.81

= 2,25,630 N

Rolling Resistance Force of Towing Vehicle, `Frr_2 = mu_2 M_2 g`

= 0.012 x 60000 x 9.81

= 7063.2 N

Drag Force of Aircraft, `Fd_1 = 1/2 rho A_1 C_(d1) V^2`

= 0.5x1.25x110x0.12x0.83^2

= 5.7 N

Drag Force of Towing Vehicle, `Fd_2 = 1/2 rho A_2 C_(d2) V^2`

= 0.5x1.25x5.23x0.2x0.83^2

= 0.45 N

Total Force required by tow for pull/ push the aircraft = `Frr_1 + Frr_2 + F_(d1) + F_(d2)` = 232699 N = 232.7 kN

Total Power required by tow for pull/ push the aircraft = Force x Velocity

= 232.7 x 0.83

= 193 kW

6B. Develop the model for the calculated force and power using Simulink.

7A. An electric powertrain with type of motor, it’s power rating, and energy requirement to fulfill aircraft towing application in Simulink.

From the below calculation, the power required by motor is 252.3kW. Hence a motor having capacity 580V, 261kW has chosen for the application.

Force required at wheels of Tow	F	232.7	kN
Power required at wheels of Tow	P	193	kW
Tire size of Tow		16.00R25
Tire Radius	r	700	mm
Torque at wheels of Tow	T = F x r	162.89	kNm
Gear Ratio	G	6	No.s
Transmission efficiency	Et	85	%
Motor Torque	Tm = T/ (Et x G)	31.94	kNm
Motor Efficiency	Em	90	%
Motor Power	Pm = P/ (Et x Em)	252.29	kW

Below showing is the simulink model of the electric drivetrain

Output result is showing below.

Rated power of 261kW achieved at Voltage 580V and Armature current 450A (580x450 = 261kW)

Duty cycle changes from 0 to 1 while speed varies from 0 to speed at Maximum Power.