Project-1: Powertrain for aircraft in runways

1. Search and list out the total weight of various types of aircrafts.

   Type	MTOW [kg]	MLW [tonnes]	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	285.700	3338	2109	Heavy	Heavy
   Boeing 747-300[7]	377,840	260.320	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	265.300			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	213.00	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	50.80	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	12.930	1300	1030	Medium	Small
   Embraer 120 Brasilia	11,500	11.25	1560	1380	Medium	Small
   BAe Jetstream 41	10,890	10.570	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

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

Fig: refernce from https://www.grc.nasa.gov/

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 comparisons.

Airspeed

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.

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.

Examples

Suppose we had an airplane that could take off on a windless day at 100 mph (liftoff airspeed is 100 mph). We are at an airport with an east-west runway that is 1 mile long. The wind is blowing 20 mph towards the west and the airplane takes off going east. The wind is blowing towards the aircraft which we call a headwind. Since we have defined a positive velocity to be in the direction of the aircraft's motion, a headwind is a negative velocity. While the plane is sitting still on the runway, it has a ground speed of 0 and an airspeed of 20 mph:

The airplane starts its take off roll and has a constant acceleration a. From Newton's second law of motion, the ground speed V at any time t is:

and the distance d down the runway at any time is:

For a fixed length runway, this specifies the time to be used in the velocity equation. Let's assume that at 5000 feet down the runway, the velocity is 80 mph. Then the airspeed is given by

and the airplane begins to fly. Now another pilot, with exactly the same airplane decides to take off to the west. The wind is now in the same direction as the motion and this is called a tailwind. The sign on the wind speed is now positive, not negative as with the headwind. The acceleration along the ground is the same, so at 5000 feet down the runway, the ground speed is again 80 mph. The airspeed is then given by:

This airplane doesn't have enough airspeed to fly. It runs off the end of the runway!

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

"Taxiing" refers to the aircraft movement while on the ground under its own power. This term excludes the accelerating run before take-off and the decelerating run after landing.

To move an aircraft you need torque, lots of torque. A conventional car (even a Jeep) would be ultra underpowered to deliver so much amount of torque as needed to move a heavy jet. And that job is done by heavy vehicles having a high side wall ratio.
The jet engine used is generally not preferred as the primary thrust for taxiing because a large amount of fuel is wasted while the aircraft is still on the ground which could have been used for flying. Since the cost of fuel is one of the biggest expenses in the airline business, many companies are planning to switch to electric taxiing to save fuel and reduce emissions.There are 2 more important reasons,
i) If the high mounted engines are powered there is a huge risk of the jet blast which may affect the surrounding building and the environment.
ii) In case of low mounted engines are turned on there is a higher possibility of any gravel or other impurities lying in the ground may enter the engine and damage it.
Here is where Pushback trucks &Electric taxiing systems use electric motors fitted inside the wheels of the aircraft’s landing gear. Electric power is supplied to these motors by an on-board Auxiliary Power Unit (APU). This innovative new approach enables airplanes to move backward and forward solely under electric power. This way, aircraft can avoid reliance on main engines for traversing the airport taxiways while burning fuel unnecessarily.

4. How an aircraft is pushed to runway when its ready to take off?  Taking aircraft till runway is called taxiing of aircraft and for the accelerating run along a runway prior to takeoff, or the
   decelerating run immediately after landing, are called the takeoff roll and landing rollout, respectively.
   So, taxiing is done by generating thrust to propel the aircraft forward, from its propellers or jet engines. Reverse thrust for
   backing up can be generated by thrust reversers or reversible pitch propellers.
   After lining up on runway and cleared for take-off, the pilot will start to advance thrust by propelling fans or by operating jet
   engines. After spooling of engines it is safe to advance the thrust levers together to the position that will enable the engines to
   deliver the amount of thrust required for take-off. The required thrust should be attained before the aeroplane’s indicated air
   speed passes 80kts. The specified speed is typically 80 knots. Below this speed the take-off may be rejected for any reason.
   Lifting up is done when the wings are lifting the weight of the airplane off the surface. In most airplanes, this is the result of the pilot rotating the nose up to increase the angle of attack (AOA). The nose is raised to a nominal 5°–15° nose up pitch attitude to increase lift from the wings and effect liftoff. For most aircraft, attempting a takeoff without a pitch-up would require cruise speeds while still on the runway.

5.Learn about take off power, tyre design, rolling resistance, tyre pressure, brake forces when landing.

Take off power:  Take off is the phase of flight that aircraft leaves the ground and become airborne.  The power required to change the phase of aircraft is called take off power. 

Stages of Power: During take-off condition the pilots first increase the engine power to 40–60% N1, low-pressure compressor RPM on Boeing
aircraft, and 50% N1 on Airbus aircraft. After setting the engine stability, the pilots then either press the TO/GA switch, causing the thrust levers to automatically advance themselves to the appropriate power setting on Boeings or manually advance the thrust levers to the TO/GA detent on Airbuses and the engine speeds then increase to provide the computed takeoff power. The advantage of having such a system is the ability to reduce wear and tear on the engines by using only as much power as is actually required to ensure the aircraft reaches safe take-off speed.

Tyre Design: 

 An aircraft tire or tyre is designed to withstand extremely heavy loads for short durations. The number of tires required for aircraft increases with the weight of the aircraft, as the weight of the airplane needs to be distributed more evenly. Aircraft tire tread patterns are designed to facilitate stability in high crosswind conditions, to channel water away to prevent hydroplaning, and for braking effect.

Design and Construction of Aircraft tyre

Carcass plies are used to form the tire. They are sometimes called casing plies. An aircraft tyre is constructed for the purpose it serves.

1. They support the weight of an aircraft while it is on the ground.
2. It also provides the necessary traction for braking and stopping of an aeroplane.
3. 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.

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.

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.

All commercial aircraft tyres approved under FAA Requirement Technical Standard Order (TSO) C62. A TSO is a minimum performance standard for specified materials, parts, and appliances used on civil aircraft.

Rolling Resistance: Rolling resistance, sometimes called rolling friction or rolling drag, is the force resisting the motion when a
body rolls on a surface. The primary cause of pneumatic tire rolling resistance is hysteresis: A characteristic of a deformable
material such that the energy of deformation is greater than the energy of recovery. The rubber compound in a tire exhibits
hysteresis.
The force that resists the motion of a body rolling on a surface is called the rolling resistance or the rolling friction.
The rolling resistance can be expressed as
Fr = cW………………………………. (1)
where
Fr = rolling resistance or rolling friction (N, lbf)
c = rolling resistance coefficient - dimensionless (coefficient of rolling friction - CRF)
W = mag
= normal force - or weight - of the body (N, lbf)
m = mass of body (kg, lb)
ag = acceleration of gravity (9.81 m/s2, 32.174 ft/s2)
The rolling resistance can alternatively be expressed as
Fr = clW / r…………………………. (2)
where
cl = rolling resistance coefficient - dimension length (coefficient of rolling friction) (mm, in)
r = radius of wheel (mm, in)
Tyre Pressure: Tyre Pressure is generally defined as the amount of air inside a tire An aircraft tyre is designed to withstand
extremely heavy loads for short durations. The number of tires required for aircraft increases with the weight of the aircraft, as
the weight of the aeroplane needs to be distributed more evenly. Aircraft tire tread patterns are designed to facilitate stability in
high crosswind conditions, to channel water away to prevent hydroplaning, and for braking effect.
Each of the twelve Boeing 777-300ER main tires is inflated to 220 psi (15 bar), weighs 120 kg (260 lb), has a diameter of 134 cm
(53 in) and is changed every 300 cycles while the brakes are changed every 2000 cycles.
Aircraft tires generally operate at high pressures, up to 200 psi (14 bar) for airliners, and even higher for business jets. The main
landing gear on the Concorde was typically inflated to 232 psi (16.0 bar), whilst its tail bumper gear tires were as high as 294 psi
(20.3 bar). The high pressure and weight load on the Concorde tyres were a significant factor in the loss of Air France Flight
4590.

Brake Forces Landing: The brake unit is powered by the hydraulic system because stopping a 200-tonne aircraft landing at 180 mph (289.682 Kmph) requires a lot of braking force. During braking condition, an electrical signal is sent from the flight deck to hydraulic actuators near the main landing gear. Here, hydraulic fluid at 3,000 pounds per square inch is used to force the brake unit against the wheel, thus slowing it down.

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

The Figure shows the towing vehicle with aircraft.  The forces acting in the towing vehicle during landing of aircraft is 

F=Frr+Fad

where Frr : Rolling resistance force

           Fad: Aerodrag force.

P=F*V. watts.

Aircraft details:

Kerb Weight (Kg) = 57600

Payload (Kg) (Only for Boeing 737 Passenger + Bags) = 10400

Total Weight (Kg) (Boeing 737) = 68000

Coefficient of rolling resistance (μrr) = 0.007

Gravitational Force g = (m s-2) = 9.81

Air Drag Calculation Data:

Air Density (Kg/m3) (rho) = 1.25

Width (m) = 4.01

Height (m) = 3.76

Frontal Area a (m2) = 15.0776

Drag Coefficient (cd) = 0.026

Speed Kmph = 8

Towing Vehicle details:

Kerb Weight (Kg) = 569

Payload (Kg) (Only Driver) = 55

Total Weight (Kg) (AP8360) = 624

Coefficient of rolling resistance (μrr) = 0.001

Gravitational Force g = (m s-2) = 9.81

Air Drag Calculation Data:

Air Density (Kg/m3) (rho) = 1.25

Width (m) = 0.8255

Height (m) = 1.26365

Frontal Area a (m2) = 1.043143075

Drag Coefficient (cd) = 0.96

Speed Kmph = 8

Forces required to pull an aircraft by a towing vehicle

The rolling resistance for the aircraft can be calculated as

Fr = c mr ag 

where

Fr = rolling resistance (N, lbf)

c = rolling resistance coefficient

mr = rolling mass (kg, lbm)

ag = acceleration of gravity (9.81 m/s2)

The friction force for the towing machine can be calculated to

Ff = μ W

= μ mf ag 

where

Ff = frictional force (N, lb)

μ = friction coefficient

W = weight (N, lbf)

mf = friction mass (kg)

excel calulcator for that

7.Design an electric powertrain with type of motor, it’s power rating, and energy requirement to fulfill aircraft  towing application. Estimate the duty cycle range to control the aircraft speed from zero to highest. Make all   required assumptions. Prepare a table of assumed parameters. Draw a block diagram of powertrain. 

For calculation,

Change the velocity to 8 kmph or 4.97097 mph

Also enter motor input = 720 RPM

Drive Cycle Source block — FTP75 (2474 seconds)

From the above Graph, we get the following details for the aircraft towing application based on assumption data.

Motor Torque: 3.714 N-m

Motor Speed: 3.086 /s

Battery SOC (%): 2.853 / ks

Battery Current (A): 2.13e-46 A/s

Assumed data,

Boeing 737 data as an assumed parameter

Total Weight (Kg) (Boeing 737) = 68000

Payload (Kg) (Only for Boeing 737 Passenger + Bags) = 10400

Total Weight (Kg) (AP8360) = 624

Width (m) = 01

Height (m) = 76

Towing Speed Kmph = 8 at towing

Total Tractive Force (N) = 769931

Total Power at given speed (kW) = 37948874 kW

Motor rated RPM for towing machine = 720

Rolling Resistance Force (N) = 56

Air Drag Force (N) = 209930864

Drag Coefficient (cd) = 026

For Duty cycle calculation

If the assumed consider losses will be 75 % (0.75) for the duty cycle at voltage armature 750

Then,

Motor voltage = Armature voltage x Duty cycle

= 750 x 0.75

= 562.5 V

Therefore at 75% (0.75) duty cycle the voltage of motor terminal will be 562.5 V and here I used Boost Converter for plotting

Duty cycle by using assumed data.

Thus,

Input voltage amplitude is (Vin) = 562.5 V

Duty cycle (D) = 75% (0.75)

Voltage output (Vout)

128.849 / ms at 250.00 Hz

Slew Rate = 954.692 / ms