Powertrain for Aircraft in runways

AIM :

1. To list out the total weight of various types of Aircrafts.

2. To make difference between Ground Speed and Air Speed.

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

4. To explain about how an aircraft is pushed to runway when its ready to take off.

5. To explain take off power, tyre design, rolling resistance, tyre pressure, brake forces when landing.

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

7. To Calculate Power and Energy requirement to fulfill aircraft towing application and to estimate the duty cycle range to control the aircraft speed from zero to highest and to draw the Electric Powertrain Block Diagram.

STUDY - 1 :

Aircraft Gross Weight :

The Aircraft gross weight is the Total aircraft weight at any moment during the flight or ground operation. An aircraft's gross weight will decrease during a flight due to fuel and oil consumption. An aircraft's gross weight may also vary during a flight due to payload dropping or in-flight-refuelling. At the moment of releasing its brakes, the gross weight of an aircraft is equal to its takeoff weight. During flight, an aircraft's gross weight is reffered to as the en-route or in-flight-weight.

An aircraft's gross weight is limited by several weight restrictions in order to avoid overloading its structure or to avoid unacceptable performance or handling qualities while in operation. Aircraft gross weight limits are established during an aircraft's design and certification period and are laid down in the aircraft's type certificate and manufacturer specification documents.The absolute maximum weight capabilities of a given aircraft are referred to as the structural weight limits. The structural weight limits are based on aircraft maximum structural capability and define the envelope for the CG charts (both maximum weight and CG limits). An aircraft's structural weight capability is typically a function of when the aircraft was manufactured, and in some cases, old aircraft can have their structural weight capability increased by structural modifications.

Maximum Design Taxi Weight (MDTW) :

The maximum design taxi weight (also known as the maximum design ramp weight (MDRW)) is the maximum weight certificated for aircraft manoeuvring on the ground (taxiing or towing) as limited by aircraft strength and airworthiness requirements.

Maximum Design Take-Off Weight (MDTOW) :

MDTOW is the maximum certificated design weight when the brakes are released for takeoff and is the greatest weight for which compliance with the relevant structural and engineering requirements has been demonstrated by the manufacturer.

Maximum Design Landing Weight (MDLW) :

The maximum certificated design weight at which the aircraft meets the appropriate landing certification requirements. It generally depends on the landing gear strength or the landing impact loads on certain parts of the wing structure.

The MDLW must not exceed the MDTOW.

Maximum Design Zero Fuel Weight (MDZFW) :

The maximum certificated design weight of the aircraft less all usable fuel and other specified usable agents (engine injection fluid, and other consumable propulsion agents). It is the maximum weight permitted before usable fuel and other specified usable fluids are loaded in specified sections of the airplane. The MDZFW is limited by strength and airworthiness requirements. At this weight, the subsequent addition of fuel will not result in the aircraft design strength being exceeded. The weight difference between the MDTOW and the MDZFW may be utilised only for the addition of fuel.

Minimum Flight Weight (MFW) :

Minimum certificated weight for flight as limited by aircraft strength and airworthiness requirements.

List of Various types of Aircraft's and its Weights :

The Various types of Aircraft's are listed below with,

MTOW - Maximum Take-Off Weight,

MLW - Maximum Landing Weight,

TOR - Take Off Run (SL, ISA+15°, MTOW),

LR - Landing Run (SL, ISA+15°, MLW)

Type	MTOW [kg]	MLW [tons]	TOR [m]	LR [m]	ICAO category	FAA category
Antonov An-225	640,000	591.7	3500		Heavy	Super
Scaled Composites Model 351 Stratolaunch	589,670		3660		Heavy	Super
Airbus A380-800[1][2][3]	575,000	394	3100	1930	Super	Super
Boeing 747-8F	447,700	346.091	3100	1800	Heavy	Heavy
Boeing 747-8	443,613	306.175	3100		Heavy	Heavy
Boeing 747-400ER	412,770	295.742	3090		Heavy	Heavy
Antonov An-124-100M	405,060	330	2520	900	Heavy	Heavy
Boeing 747-400	396,900	295.742	3018	2179	Heavy	Heavy
Lockheed C-5 Galaxy[4][5][6]	381,000	288.417	2530	1494	Heavy	Heavy
Boeing 747-200[7]	377,840	285.7	3338	2109	Heavy	Heavy
Boeing 747-300[7]	377,840	260.32	3222	1905	Heavy	Heavy
Airbus A340-500[8]	371,950	240	3050	2010	Heavy	Heavy
Airbus A340-600[8]	367,400	256	3100	2100	Heavy	Heavy
Boeing 777F	347,800	260.816	2830		Heavy	Heavy
Boeing 777-300ER	351,800	251.29	3100		Heavy	Heavy
Boeing 777-200LR	347,450	223.168	3000		Heavy	Heavy
Boeing 747-100[7]	340,200	265.3			Heavy	Heavy
Airbus A350-1000	308,000	233.5			Heavy	Heavy
Boeing 777-300	299,370	237.683	3380		Heavy	Heavy
Boeing 777-200ER	297,550	213	3380	1550	Heavy	Heavy
Airbus A340-300[8][9]	276,700	190	3000	1926	Heavy	Heavy
McDonnell Douglas MD-11	273,300	185	2990	1890	Heavy	Heavy
Airbus A350-900	270,000	175	2670	1860	Heavy	Heavy
Ilyushin Il-96M	270,000	195.04	3115	2118	Heavy	Heavy
McDonnell Douglas DC-10	256,280	183	2990	1890	Heavy	Heavy
Boeing 787-9[10]	254,000	192.777	2900		Heavy	Heavy
Boeing 787-10[10]	254,000	201.849			Heavy	Heavy
Airbus A340-200[8][11]	253,500	181	2990		Heavy	Heavy
Ilyushin IL-96-300	250,000	175	2600	1980	Heavy	Heavy
Airbus A330-300[12][13]	242,000	185	2500	1750	Heavy	Heavy
Airbus A330-200[12][13]	242,000	180	2220	1750	Heavy	Heavy
Lockheed L-1011-500	231,300	166.92	2636		Heavy	Heavy
Boeing 787-8[10]	228,000	172.365	3300	1695	Heavy	Heavy
Lockheed L-1011-200	211,400				Heavy	Heavy
Ilyushin IL-86	208,000	175			Heavy	Heavy
Boeing 767-400ER	204,000	158.758	3414		Heavy	Heavy
Airbus A300-600R[14]	192,000	140	2385	1555	Heavy	Heavy
Boeing 767-300ER	187,000	136.08	2713	1676	Heavy	Heavy
Concorde	185,000	111.1	3440	2220	Heavy	Heavy
Airbus A300-600[14]	163,000	138	2324	1536	Heavy	Heavy
Boeing 767-300	159,000	136.078	2713	1676	Heavy	Heavy
Airbus A310-300[14]	157,000	124	2290	1490	Heavy	Heavy
Vickers VC10	152,000	151.9			Heavy	Heavy
Boeing 707-320B[15]	151,000	97.5			Heavy	Heavy
Boeing 707-320C[15]	151,000	112.1			Heavy	Heavy
Douglas DC-8-61	147,000				Heavy	Heavy
Airbus A310-200[14]	142,000	123	1860	1480	Heavy	Heavy
Airbus A400M	141,000	122	980	770	Heavy	Heavy
Douglas DC-8-32	140,000				Heavy	Heavy
Douglas DC-8-51	125,000				Medium	Large
Boeing 757-300	124,000	101.6	2550	1750	Medium	Large
Boeing 707-120B[15]	117,000	86.3			Medium	Large
Boeing 757-200	116,000	89.9	2347	1555	Medium	Large
Boeing 720B[16]	106,000	79.5			Medium	Large
Boeing 720[16]	104,000	79.5			Medium	Large
Tupolev Tu-154M	104,000	80			Medium	Large
Tupolev Tu-204SM	104,000	87.5	2250		Medium	Large
Convair 880	87,500				Medium	Large
Boeing 737-900	85,000	66.36	2500	1704	Medium	Large
Boeing 737-900ER	85,000	71.35	2804	1829	Medium	Large
Boeing 727-200 Advanced[17]	84,000	70.1			Medium	Large
Airbus A321-100[18]	83,000	77.8	2200	1540	Medium	Large
Boeing 737-800	79,000	65.32	2308	1634	Medium	Large
Boeing 727-200[17]	78,000	68.1			Medium	Large
McDonnell-Douglas MD-83	73,000	63.28			Medium	Large
Boeing 727-100[17]	72,500	62.4			Medium	Large
Boeing 727-100C[17]	72,500	62.4			Medium	Large
McDonnell-Douglas MD-90-30	71,000	64.41	2165	1520	Medium	Large
de Havilland Comet 4	70,700				Medium	Large
Boeing 737-700	70,000	58.06	1921	1415	Medium	Large
Airbus A320-100[18]	68,000	66	1955	1490	Medium	Large
Boeing 737-400	68,000	54.9	2540	1540	Medium	Large
de Havilland Comet 3	68,000				Medium	Large
Boeing 377	67,000				Medium	Large
Boeing 737-600	66,000	54.66	1796	1340	Medium	Large
Airbus A220-300	65,000	57.61	1890	1494	Medium	Large
Hawker Siddeley Trident 2E	65,000				Medium	Large
Airbus A319[18]	64,000	62.5	1850	1470	Medium	Large
Boeing 737-300	63,000	51.7	1939	1396	Medium	Large
Boeing 737-500	60,000	49.9	1832	1360	Medium	Large
Airbus A220-100	59,000	50.8	1463	1356	Medium	Large
Airbus A318[18]	59,000	57.5	1375	1340	Medium	Large
Boeing 717-200HGW	55,000	47.174	1950		Medium	Large
Douglas DC-7	55,000				Medium	Large
de Havilland Comet 2	54,000				Medium	Large
Boeing 717-200BGW	50,000	46.265	1950		Medium	Large
de Havilland Comet 1	50,000				Medium	Large
Douglas DC-6A	48,600				Medium	Large
Douglas DC-6B	48,500				Medium	Large
Embraer 190[19]	48,000	43	2056	1323	Medium	Large
Caravelle III	46,000				Medium	Large
Fokker 100	46,000	39.95	1621	1350	Medium	Large
Douglas DC-6	44,000				Medium	Large
Avro RJ-85	42,000	36.74			Medium	Large
Handley Page Hermes	39,000				Medium	Large
Embraer 175[20]	37,500	32.8	2244	1304	Medium	Large
Bombardier CRJ900[21]	36,500	33.345	1778	1596	Medium	Large
Embraer 170[22]	36,000	32.8	1644	1274	Medium	Large
Bombardier CRJ700	33,000	30.39	1564	1478	Medium	Large
Douglas DC-4	33,000				Medium	Large
Vickers Viscount 800	30,400				Medium	Large
Bombardier Q400	28,000	28.01	1219	1295	Medium	Large
Bombardier CRJ200	23,000	21.319	1918	1479	Medium	Large
ATR 72-600	22,800	22.35	1333	914	Medium	Large
Saab 2000	22,800	21.5	1300		Medium	Large
Embraer ERJ 145	22,000	19.3	2270	1380	Medium	Large
ATR 42-500	18,600	18.3	1165	1126	Medium	Small
Saab 340	13,150	12.93	1300	1030	Medium	Small
Embraer 120 Brasilia	11,500	11.25	1560	1380	Medium	Small
BAe Jetstream 41	10,890	10.57	1493	826	Medium	Small
Learjet 75[23]	9,752	8.709	1353	811	Medium	Small
Pilatus PC-24[24]	8,300	7.665	893	724	Medium	Small
Embraer Phenom 300[25]	8,150	7.65	956	677	Medium	Small
Beechcraft 1900D	7,765	7.605	1036	853	Medium	Small
Cessna Citation CJ4[26]	7,761	7.103	1039	896	Medium	Small
de Havilland Hercules	7,000				Medium	Small
Embraer Phenom 100	4,800	4.43	975	741	Light	Small

STUDY - 2 :

Difference between Air speed and Ground speed :

There are two different types of speeds when talking about airplanes,

---> Ground Speed

---> Air Speed

While ground speed is the airplane’s speed relative to the surface of the Earth, airspeed – at least true airspeed – is its speed relative to the air it is flying in.

As mentioned above, true airspeed is simply the speed at which an aircraft is moving relative to the air it is flying in. As such, it’s 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. One thing that should be noted here is that it’s its horizontal rather than vertical speed – an aircraft climbing completely vertically would have a ground speed of zero.

In other words, while airspeed is what determines whether there is enough airflow around an aircraft to make it fly, ground speed is what determines how fast an aircraft will get to its destination.

The relationship between airspeed and ground speed is fairly simple. Ground speed is simply the sum of airspeed and wind speed.

If the aircraft is flying in the same direction as the wind is blowing, the aircraft experiences tailwind, and its ground speed is higher than its airspeed. On the other hand, if the wind is blowing against the direction the aircraft is traveling in, the aircraft experiences headwind, and its ground speed is lower than its airspeed.

Fig : Relative Velocity - Aircraft Reference

Aerodynamic forces are generated by an object moving through a fluid (liquid or gas). A fixed object in a static fluid does not generate aerodynamic forces. To properly define the relative velocity, it is necessary to pick a fixed reference point and measure velocities relative to the fixed point. In this above fig, the reference point is fixed to the ground, but it could just as easily be fixed to the aircraft itself. It is important to understand the relationships of wind speed to ground speed and airspeed.

Wind Speed :

For a reference point picked on the ground, the air moves relative to the reference point at the wind speed. Notice that the wind speed is a vector quantity and has both a magnitude and a direction.

Ground Speed :

For a reference point picked on the ground, the aircraft moves relative to the reference point at the ground speed. Ground speed is also a vector quantity so a comparison of the ground speed to the wind speed must be done according to rules for vector comparisions.

Air Speed :

The important quantity in the generation of lift is the relative velocity between the object and the air, which is called the airspeed. Airspeed cannot be directly measured from a ground position, but must be computed from the ground speed and the wind speed. Airspeed is the vector difference between the ground speed and the wind speed.

Airspeed = Ground Speed - Wind Speed

Fig : Air Speed vs Ground Speed

On a perfectly still day, the airspeed is equal to the ground speed. But if the wind is blowing in the same direction that the aircraft is moving, the airspeed will be less than the ground speed.

STUDY - 3 :

Taxiing (rarely spelled taxying) is the movement of an aircraft on the ground, under its own power, in contrast to towing or push-back where the aircraft is moved by a tug. The aircraft usually moves on wheels, but the term also includes aircraft with skis or floats (for water-based travel).

An airplane uses taxiways to taxi from one place on an airport to another; for example, when moving from a hangar to the runway. The term "taxiing" is not used for the accelerating run along a runway prior to takeoff, or the decelerating run immediately after landing, which are called the takeoff roll and landing rollout, respectively.

During taxi operation, aircraft burns a lot of fuel, generates large quantity of emissions and the engine in the process of taxiing is exposed to damage due to Foreign Object Damage (FOD). This results in huge operational and maintenance cost as well as carbon emission tax which are all at the expense of the airline. The major disadvantages of using aircraft engine power is,

- Fuel Consumption,

- Wear and Tear on the engine,

- Unnecessary jet blast and noise.

Although many aircraft are capable of moving themselves backwards on the ground using reverse thrust (a procedure referred to as a powerback), the resulting jet blast or prop wash might cause damage to the terminal building or equipment. Engines close to the ground may also blow sand and debris forward and then suck them into the engine, causing damage to the engine. A pushback is therefore the preferred method to move the aircraft away from the gate.So, it is not recommended to use aircraft engine power to move it on the ground at Airport.

STUDY - 4 :

In aviation, pushback is an airport procedure during which an aircraft is pushed backwards away from an airport gate by external power. Pushbacks are carried out by special, low-profile vehicles called pushback tractors or tugs.

Closer to departure, an aircraft tug will park right in front of the nose wheel. The tug might be directly attached to the plane's nose gear with a tow bar, or could be a "wheel-lift" tug. By using Pushback tug or tractor an Aircraft is pushed to runway when its ready to takeoff.

Fig : Pushback Tug with Aircraft and Remotely controlled aircraft tug

Fig : Pushback tug moves the Aircraft

Pushbacks at busy aerodromes are usually subject to ground control clearance to facilitate ground movement on taxiways. Once clearance is obtained, the pilot will communicate with the tractor driver (or a ground handler walking alongside the aircraft in some cases) to start the pushback. To communicate, a headset may be connected near the nose gear.

Since the pilots cannot see what is behind the aircraft, steering is done by the pushback tractor driver and not by the pilots. Depending on the aircraft type and airline procedure, a bypass pin may be temporarily installed into the nose gear to disconnect it from the aircraft's normal steering mechanism.

Once the pushback is completed, the towbar is disconnected, and any bypass pin removed. The ground handler will show the bypass pin to the pilots to make it clear that it has been removed. The pushback is then complete, and the aircraft can taxi forward under its own power.

STUDY - 5 :

Take off Power :

Takeoff is the phase of flight in which an aerospace vehicle leaves the ground and becomes airborne.For aircraft that take off horizontally, this usually involves starting with a transition from moving along the ground on a runway. Takeoff is the opposite of landing.

For light aircraft usually full power is used during takeoff. Large transport category (airliner) aircraft may use a reduced power for takeoff, where less than full power is applied in order to prolong engine life, reduce maintenance costs and reduce noise emissions. In some emergency cases, the power used can then be increased to increase the aircraft's performance. Before takeoff, the engines, particularly piston engines, are routinely run up at high power to check for engine-related problems.

For example, small piston engine airplanes use full power for takeoff as a rule. But jet airliners may use less than full power, but enough power for a safe takeoff. This is known as “flex” thrust, or “assumed temperature”. Boeing aircraft have a system which reduces takeoff thrust by a certain percentage.

Tyre Design :

An aircraft tyre is designed to withstand extremely heavy loads while landing, take off, taxing and parking. Carcass plies are used to form the tire. They are sometimes called casing plies. An aircraft tyre is constructed for the purpose it serves.

- They support the weight of an aircraft while it is on the ground.

- It also provides the necessary traction for braking and stopping of an aeroplane.

- Tyre also helps to absorb the shock of landing and provide cushioning the roughness of takeoff, roll-out, and taxi operations.

Unlike an automobile or truck tyre, it does not have to carry a load for a long period of continuous operation. However, an aircraft tyre absorbs the high impact loads of landing and also it’s operating at high speeds for a short time when required.

Fig : Design and Construction of Aircraft tyre

Some of the technical aspects of aircraft tyre is,

Retreading – Retreading is methods of restoring a worn tyre by renewing the tread area or by renewing the tread area plus one or both sidewalls. Repairs are included in the tyre retreading process.

Load Rating – Load rating is the maximum permissible load at a specified inflation pressure.

Ply Rating – Ply Rating is used to identify the maximum recommended load rating and inflation pressure for a specified tyre. It is an index of tyre strength.

Speed Rating – The speed rating is the maximum takeoff speed to which the tyre has been tested.

Skid Depth – Skid depth is the distance between the tread surface and the deepest groove as measured in the mould.

Aircraft tyres must have an approved speed and load rating and have sufficient clearance when retracted through landing gear to allow for tyre growth. Tyre growth is the increase in the size of the tyre due to centrifugal forces at high speed.

Rolling Resistance :

Rolling resistance, sometimes called rolling friction or rolling drag, is the force resisting the motion when a body (such as a ball, tire, or wheel) rolls on a surface.

The "rolling resistance coefficient" is defined by the following equation,

`F=C_(rr)*N`

where,

F - Rolling resistance force,

`C_(rr)`- Dimensionless rolling resistance coefficient or coefficient of rolling friction (CRF),

N - Normal force, the force perpendicular to the surface on which the wheel is rolling.

Tyre Pressure :

Aircraft tires generally operate at high pressures, up to 200 psi (14 bar; 1,400 kPa) for airliners, and even higher for business jets. In addition, the pressure in the bottle or tire-servicing cart can be as high as 3,000 psi.

Because of the high pressures and extreme temperatures at which aircraft tires operate, they do not hold air perfectly. In fact, an aircraft tire can lose up to 5 percent of its pressure in 24 hours and still be perfectly serviceable.

Large aircraft tires are filled with nitrogen not air. Air is a combination of gasses that at low atmospheric temperatures and pressure can turn to ice inside the tires or under high temperatures and pressures even explode.

Fig : Tire Pressure Maintenance

Brake force when Landing :

Aircraft brakes stop a moving aircraft by converting its kinetic energy to heat energy by means of friction between rotating and stationary discs located in brake assemblies in the wheels. These disc brakes alone are not enough to bring the airplane to a safely controlled standstill though. To slow down as quickly as possible and to maximize the function of the wheel brakes, jet airplanes also commonly use thrust reversers and flaps. These systems are engaged after the wheels of the airplane touch the runway during landing.

Modern aircraft use two different braking systems to do this: the spoilers and the thrust reversers. The interesting thing here is that both of these systems are controlled by a computer. As soon as the wheels are put on the ground, the spoilers fully activate themselves. These spoilers are actually flaps which are located on the end of the wings. They function to reduce the aerodynamic lift and increase the drag.

These flaps are an important factor in the braking system because, without them, the friction of the wheels will not be enough for efficient braking. The second system, the reversers, are located in the engines and can be activated, so the exhaust of the engine is redirected forward, as opposed to backward. These reversers also help in reducing the amount of stress the wheels have to tolerate. And although they are controlled by the computers, in the case of an emergency, the pilots are prepared to take over manually.

STUDY - 6 :

Calculating force and power required to push / pull an aircraft by a towing vehicle.

Input :

The TPX-200 is a towbarless aircraft tractor especially designed for push back operation and short distance maintenance towing on aircraft up to 250 tons, including:

• Airbus A318/A319/A320/A321, A300/A310, A330/A340-300, A350, MD80/MD90, DC9, DC10, MD11
• Boeing B717, B737, B727, B757, B767 B787, B777

The TPX series have a unique cradle design with a central articulation between front and rear chassis preventing jack-knifing situations. The driver is perfectly aligned with NLG and very close to the cradle to perform safe operations. Its failsafe and fully automated loading and unloading cycle is unmatched in its simplicity and security.

Like all TLD tractors, the TPX series are efficient in design (2WS, 2WD) simplifying operational and maintenance tasks while offering the best TCO of comparable tractors.

Fig : TLD TPX-200 Towbarless Aircraft Pushback Tractor

Specifications :

Vehicle Maximum Speed - 22kmph,

Weight - 12000 kg,

Fig : Boeing 737-500

Formula :

For Calculating Friction Force :

`F_f=mu*m*g`

where,

`mu`- Co-efficient of rolling resistance(0.012),

`m` - mass(kg),

Mass(m) = Mass of Aircrfat(m1) + Mass of Pushback Tractor(m2)

= 12000+60000

m = 72000 kg.

g - Acceleration due to gravity 9.81 m/s^2.

For Calculating Drag Force :

`F_d=0.5*rho*C_d*A*v^2`

where,

`F_d`-Drag Force(N),

`rho`-Density (`1.225 (kg)/m^3`),

`C_d`-Co-efficient of Drag(0.02),

A - Frontal Area(`m^2`),

A = Width of the Aircraft * Height of the Aircraft

= 28.88 * 11.13

A = 321.43 `m^2`

`v^2`- Velocity(Let us Consider Towing vehicle running at a Velocity of 17kmph(4.7 m/s)),

Calculation :

Calculation of Friction Force :

`F_f=mu*m*g`

`F_f=0.012*72000*9.81`

`F_f=8475.84 N`

Calculation of Drag Force :

`F_d=0.5*rho*C_d*A*v^2`

`F_d=0.5*1.225*0.02*321.43*(4.7^2)`

`F_d=88.75 N`

Calculation of Total Force :

`F_(te) = F_f+F_d`

`F_(te)`= 8475.84 + 88.75

`F_(te)`= 8564.59 N

Calculation of Torque (T) :

T = `F_(te)` * r

= 8564.59*0.5715

T = 4894.66 Nm

Calculation of Power(P) :

`P = F_(te)*v`

= 8564.59 * 4.7

P = 40.253 kW

Result :

Force required to Push / Pull an aircraft by a TLD TPX-200 Towbarless Aircraft Pushback Tractor is 8564.59 N.

Power required to Push / Pull an aircraft by a TLD TPX-200 Towbarless Aircraft Pushback Tractor is 40.25 kW.

STUDY - 7 :

Calculation of Energy :

Power is the amount of energy transferred or converted per unit time. The formula that links the Energy and Power is,

E = P * t

where,

E - Energy(J),

P - Power(W),

t - time(sec).

From Study-6 we obtained the required Power to Push/Pull an Aircraft(Boeing 737-500) by TLD TPX-200 Towbarless Aircraft Pushback Tractor.

Power (P) = 40.25 kW,

Let us consider time taken for towing an aircraft as 5min(300 sec), From that we can find the required Energy to Push/Pull an aircraft by an towing Vehicle.

E = P * t

E = 40250 * 300

E = 12.075 kJ.

For Converting kJ to kWh divide by 3600,

E = 12075/3600

E = 3.354 kWh.

Calculating Duty Cycle Range :

For Calculating Duty Cycle,

Duty Cycle(D) = Output Power (`P_o`) / Input Power (`P_i`)

We already know the Output Power(Required Power for towing an aircraft is `P_o`=40250 W) and for calculating the Input Power, let us assume Voltage(480V) and Current(110A)

Input Power (`P_i`) = Voltage * Current

`P_i` = 480 * 110

`P_i` = 52800 W

Therefore,

`D=P_o/P_i`

`D=40250/52800`

`D=0.7623`

D = 76.23%

Block Diagram of Electric Powertrain :

Fig : Block Diagram of Electric Powertrain

Result :

---> 40.25 kW Power and 3.354 kWh Energy is required to fulfill the aircraft towing application.

---> Duty Cycle range is 76.23% for a 480 V Battery to control the aircraft towing Speed from 0 to 17 kmph.