Project-1: Powertrain for aircraft in runways

Project-1: Powertrain for aircraft in runways Aircraft Towing and Ground Handling BY SANKET AWASTHY

Aim: To develop an efficient and safe aircraft towing and ground handling system.

Objectives:

• To determine the total weight of various types of aircraft and their corresponding ground handling requirements.
• To understand the difference between ground speed and air speed and its impact on aircraft ground handling.
• To identify the reasons why it is not recommended to use aircraft engine power to move it on the ground at an airport.
• To explore the different methods and equipment used to push an aircraft to the runway for takeoff.
• To investigate the factors that affect takeoff power, tire design, rolling resistance, tire pressure, and brake forces when landing.
• To calculate the force and power required to push/pull an aircraft by towing a vehicle using necessary assumptions.
• To develop a model for the calculated force and power using Simulink.
• To design an electric powertrain system that can handle aircraft towing applications using Simulink.
• To estimate the duty cycle range to control the aircraft speed from zero to highest.
• Prepare a table of assumed parameters and draw a block diagram of the powertrain system.
• To evaluate the efficiency and safety of the developed aircraft towing and ground handling system.

Key Highlights:

• Comprehensive research on aircraft towing and ground handling requirements and challenges.
• Calculation of the force and power needed to move different types of aircraft on the ground using a towing vehicle.
• Development of a simulation model using Simulink to optimize the towing process.
• Design of an electric powertrain system suitable for aircraft towing applications.
• Assessment of the efficiency and safety of the developed system in comparison to existing methods.
  
  
  
  

  Part A:

  1. Search and list the total weight of various types of aircraft.
  
  
  
  ANSWER:
  
  
  

  The total weight of various types of aircraft can vary greatly depending on the specific model and its configuration. For example, a small single-engine Cessna 172 may weigh around 2,400 pounds, while a large commercial aircraft like the Boeing 747 can weigh over 800,000 pounds. Other examples include the Airbus A380 at 1.2 million pounds, the Bombardier Global 7500 at 106,250 pounds, and the Bell Boeing V-22 Osprey at 52,600 pounds.
  

  Aircraft Gross Weight:

  -As per the federal aviation department, aircraft gross weight is defined as the total weight at any moment during flight or ground operation.

  -The aircraft's gross weight decreases during the flight due and oil consumption. In some cases, gross weight (aircraft) may vary due to a drop in the payload or inflight refueling, whereas on the other hand when the brakes are released the gross weight will be equal to the take-off weight.

  -During flight an aircraft's gross weight will be referred to as inflight weight.

  

  
  
  

  The aircraft gross weight (also known as the all-up weight and abbreviated AUW) 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.

  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 referred to as the en-route weight or in-flight weight.

  Weight of Various Types of Aircraft Weight:

  1. Glider

  A glider is a fixed-wing plane that is supported in flight by the dynamic reaction of the air against its lifting surfaces, and whose free weight does not depend on an engine. Most gliders do not have an engine, although motor gliders have small engines for extending their flight, when necessary, by sustaining the altitude (normally a sailplane is on a continuously descending slope) with some being powerful enough to take off self-launch.

  Weight of Glider planes: 110 kg - 200 kg

  2. Powered Lift

  A powered lift aircraft takes off vertically under engine power but uses a fixed wing for horizontal flight. These aircraft do not need a long runway to take off and land, like helicopters, but they have a speed and performance similar to standard fixed-wing aircraft in combat or other situations.

  Weight: 160 kg

  3. Fighter Aircraft

  A fighter aircraft, often referred to simply as a fighter, is a military fixed-wing aircraft designed primarily for air-to-air combat against other aircraft. The key performance features of a fighter include not only its firepower but also its high speed and maneuverability relative to the target aircraft.

  Weight: 13500 kgs

  4. Transport Planes:

  Military transport aircraft or military cargo aircraft are used to airlift troops, weapons and other military equipment to support military operations. Transport aircraft can be used for both strategic and tactical missions, and are often diverted to civil emergency relief missions.

  Weight: 250,000 kg

  5. Aerobatic Planes

  An aerobatic aircraft is an aerodyne (a heavier-than-air aircraft) used in aerobatics, both for flight exhibitions and aerobatic competitions

  

  Weight: 771 kg
  
  
  
  REFERENCE: https://aerocorner.com/
  
  

  Types of aircraft weights are the following:

  Manufacturer's Empty Weight: This is the weight of the aircraft as it comes from the manufacturer, including all the necessary parts and components for flight but excluding any baggage, passengers, or fuel.

  Zero Fuel Weight: This is the weight of the aircraft without any usable fuel on board, but including any unusable fuel. This weight is used to determine the maximum payload that the aircraft can carry.

  Payload: The payload is the total weight of all cargo, passengers, and usable fuel on board the aircraft. In the case of cargo flights, the payload refers to the total weight of all the containers and logistics that the aircraft is carrying.

  Maximum Takeoff Weight: This is the maximum weight at which the aircraft is permitted to take off. It includes the weight of the aircraft, fuel, passengers, cargo, and any other items on board.

  Regulated Takeoff Weight: This weight varies for each takeoff and is dependent on various factors such as the flap setting, altitude, and length of the runway. However, it can never be higher than the maximum takeoff weight.

  Maximum Landing Weight: This is the maximum weight at which an aircraft is permitted to land. It takes into account the weight of the aircraft, passengers, cargo, and fuel.

  Maximum Ramp Weight: This is the maximum weight at which the aircraft can be maneuvered on the ground, such as during towing or while taxiing.

  
  Operating Weight:
  It is the weight of the aircraft including crew, passengers, fuel, and cargo.

  Maximum Zero Fuel Weight:
  It is the highest weight allowed for an aircraft without fuel.

  Usable Fuel Weight:
  It is the weight of the fuel that can be used by the aircraft during the flight.

  Gross Weight:
  It is the total weight of an aircraft when fully loaded with passengers, cargo, fuel, and other necessary items.

  Taxi Weight:
  It is the weight of an aircraft during taxiing, which includes the weight of the aircraft, crew, passengers, and fuel.

  Fuel Burn Weight:
  It is the weight of the fuel that is burned during a flight.

  Structural Weight:
  It is the weight of the structure of the aircraft, including the fuselage, wings, and tail.

  Center of Gravity:
  It is the point on the aircraft where the total weight is considered to be concentrated. The center of gravity must be within specific limits for the aircraft to be stable during flight.

  
  Other important terminologies related to aircraft weight include:
  
  

  Basic Operating Weight: This is the weight of the aircraft with standard equipment, crew, and oil. It excludes any passengers, cargo, or additional fuel.

  Gross Weight: This is the total weight of the aircraft, including all passengers, cargo, fuel, and any other items on board.

  Center of Gravity: This is the point at which the aircraft's weight is evenly distributed in all directions. It is an important factor in determining the aircraft's stability and maneuverability.

  Fuel Burn: This is the weight of fuel that is burned during flight. It is taken into account when calculating the aircraft's weight and balance.

  Weight and Balance: This is the process of calculating and adjusting the weight of the aircraft to ensure that it is within safe limits and that the center of gravity is properly balanced. It is critical to the safety and performance of the aircraft.

  
  
  

  Here are some particular models with the approximate weights of various types of aircraft:

  Cessna 172: 757 kg (1670 lbs)
  
  
  
  Boeing 737: 41,145 kg (90,718 lbs)
  
  
  
  
  
  Airbus A320: 73,500 kg (162,040 lbs)
  
  
  
  Boeing 747: 178,100 kg (392,000 lbs)
  
  
  
  
  
  Airbus A380: 575,000 kg (1,268,000 lbs)
  
  
  
  Embraer E175: 22,500 kg (49,604 lbs)
  
  
  
  
  
  
  Bombardier Global 7500: 48,200 kg (106,262 lbs)
  
  
  
  Beechcraft King Air 350: 4,903 kg (10,800 lbs)
  
  
  
  Gulfstream G650: 45,360 kg (100,000 lbs)
  
  
  C-17 Globemaster III: 265,350 kg (585,000 lbs)
  
  
  Note that these weights are approximate and can vary depending on the aircraft's configuration, fuel load, cargo weight, and other factors.
  
  

  Here are different types of aircraft for different uses along with their weight ranges:

  Commercial airliners: These aircraft are designed for transporting passengers and cargo on scheduled or non-scheduled flights.
  Examples: Airbus A320, Boeing 737, Bombardier CRJ700
  Weight range: 60,000 lbs to 1.2 million lbs
  
  Business jets: These aircraft are designed for executives and business travel, offering speed and luxury.
  Examples: Gulfstream G650, Bombardier Global 6000, Cessna Citation X
  Weight range: 10,000 lbs to 100,000 lbs
  
  
  General aviation: These aircraft are used for personal or recreational purposes.
  Examples: Cessna 172, Piper PA-28, Beechcraft Bonanza
  Weight range: 1,000 lbs to 12,500 lbs
  
  
  Military aircraft: These aircraft are used by armed forces for a variety of purposes, including air combat, transportation, and reconnaissance.
  Examples: F-16 Fighting Falcon, Boeing F/A-18 Super Hornet, Lockheed Martin C-130J Hercules
  Weight range: 10,000 lbs to 925,000 lbs
  
  
  Helicopters: These aircraft are designed for vertical takeoff and landing, and are used for a variety of purposes including transportation, emergency medical services, and military operations.
  Examples: Bell 206, Sikorsky S-92, Eurocopter EC135
  Weight range: 1,000 lbs to 55,000 lbs
  
  
  Agricultural aircraft: These aircraft are used for crop dusting and spraying.
  Examples: Air Tractor AT-802, Thrush 510P, Piper Pawnee
  Weight range: 2,000 lbs to 22,000 lbs
  
  Experimental and homebuilt aircraft: These aircraft are built by individuals or small companies, and are not certified for commercial use.
  Examples: Vans RV-7, Zenith CH-750, Sonex Aircraft Sonex
  Weight range: 250 lbs to 3,000 lbs.

  
  
  
  

  2. Is there any difference between ground speed and airspeed?
  
  
  
  Yes, there is a difference between ground speed and air speed. Ground speed is the speed at which an aircraft is moving relative to the ground, while airspeed is the speed at which the aircraft is moving relative to the air around it. Ground speed can be affected by factors such as wind direction and speed, while airspeed is typically measured using pitot-static instruments on the aircraft.
  
  
  

  *Ground speed:

  -They are the airplane speed which is related to the ground.

  -They are the speed which determines how fast the airplane will reach the destination.

  -They are calculated by summing up the airspeed and windspeed.

  *Airspeed:

  -It refers to the speed which is relative to air it is flying in.

  -They determine whether there is enough airflow around an aircraft to make it lift.

  -They are independent of ground speed.

  

  

  -The above two diagrams relative velocity with respect to aircraft reference and ground reference.

  -Here wind speed is the vector difference between ground and airspeed. On a perfectly still day the wind speed is zero and it is equal to the ground speed.

  -If the measured airspeed is greater than the observed ground speed the wind speed becomes positive.
  
  
  
  

  3. Why is it not recommended to use aircraft engine power to move it to the ground at the Airport?
  
  
  
  It is not recommended to use aircraft engine power to move it on the ground at an airport because it can create safety hazards. The exhaust from the engines can create debris and cause damage to equipment and people on the ground, and the jet blast can also cause damage and injury. In addition, using the engines for ground movement can increase wear and tear on the engines, reducing their overall lifespan.
  
  
  
  
  
  
  ALSO, USE THE BELOW REFERENCE FOR QUESTION 4
  
  

  Towing is coupling two or more objects together so that they may be pulled by a designated power source or sources. The towing source may be a motorized land vehicle, vessel, animal, or human, and the load being anything that can be pulled

  Although many aircraft are capable of moving themselves backward on the ground using reverse thrust (a procedure referred to as a power back), the resulting jet prop 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.

  Although most aircraft are capable of moving themselves backward on the ground using reverse thrust, a procedure called as a power back, it is not typically done due to the following reasons:

  • The jet blast from the engines can damage the terminal building and nearby equipment. It can even throw away people standing nearby.
  • Engines can blow sand and debris.
  • Engines can suck in sand and debris which can cause serious damage to the engine.
  • It is easier for the truck driver to see the surroundings better than the pilot sitting in the cockpit with limited windows.
  • The pushback truck driver knows the airport better than the pilot.
  • The plane engines are very loud. This noise can add up substantially when multiple planes are moving around the airport. It won't be a pleasant experience for people sitting inside the terminal, as most people don't even like the sound of powerful motorbikes.
  • It saves fuel. Virgin Atlantic had proposed a new system in which pushback trucks will push the plane all the way to the runway to save fuel and reduce the impact on the nearby environment.

  
  
  Taxing is the movement of an aircraft on the ground, under its own power, in contrast to towing or pushback 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).

  The power for taxiing comes from the engines themselves. If it is a propeller-powered aircraft, the propeller provides thrust and pulls the aircraft, like it would in the air. If it is a jet engine, the exhaust air that comes out of the engine creates a forward force due to Newton's third law and moves the airplane.

  Airliners have nose wheel steering, controlled by a cockpit control called a tiller. The tiller allows the nose wheel to rotate at quite extreme angles making tighter turns possible. It also reduces fuel consumption as you do not need much engine power during taxiing. If rudders were used, the power has to be increased to make sure sufficient air flows over the rudder surface to make it effective.

  Once on the takeoff roll and the airplane gains sufficient speed i.e. enough air flows over the rudders, pilots go back to using the rudder pedals to maintain the center line.

  Some large airplanes with multi-wheel main gears have a tendency to scrub the tyres on the tarmac when the nose wheel is steered. To counter this problem, an automatic main gear steering is inbuilt into the aircraft. This makes the main gears turn in the opposite direction to that of the nose wheel, greatly decreasing the wear on the tyres.

  Generally, most airplanes can move in a reverse manner by making use of reverse thrust technology. But in most practical, it is not possible because when airplanes start using reverse thrust it will consume a lot of fuel as well as causes a lot of noise and also be hazardous for the people working nearby.

  

  -Another reason for not using reverse thrust is that the jet blast can cause damage to terminal buildings or their equipment. Since the engine is also close to the ground it will blow off the sand and debris forward and sucks it to the engine and causing damage to it.

  

  
  
  

  4. How is an aircraft pushed to the runway when it's ready to take off?
  
  
  
  
  
  Aircraft are typically pushed to the runway using a ground vehicle called a pushback tug or pushback tractor. The tug attaches to the aircraft using a towbar, and the tug's driver then moves the aircraft backward away from the gate and onto the taxiway, where the aircraft's engines can be started and it can begin its takeoff roll.
  
  
  

  When an aircraft is ready to take off, it is typically pushed back from the gate or parking spot by a specialized vehicle called a pushback tug. This vehicle attaches to the front landing gear of the aircraft and uses its own engine to move the plane back away from the gate.

  Once the aircraft is in position for taxiing, its own engines are used to move the plane to the runway. The pilot or ground crew will communicate with air traffic control to get clearance for taxiing and will follow a designated taxi route to the runway.

  During takeoff, the aircraft's engines provide the necessary thrust to achieve the required takeoff speed. Takeoff power is the maximum power output of the engines during this phase. The pilot will apply full takeoff power and once the aircraft reaches the required takeoff speed, the nose of the aircraft is lifted off the ground and the aircraft becomes airborne.

  Once all passengers have boarded and pilots have been given authorisation to steer the aircraft away from the parking area, the first procedure the aircraft undertakes is pushback. Once it is a fair distance away from the terminal gate, groundstaff and any equipment, it begins taxiing. Taxiing is the procedure before the aircraft takes flight, in which the aircraft moves on the taxiway using its own engine power without the assistance of any towing vehicles. Taxiways are well designed paths for the aircraft to navigate through to get to the runway (refer to figure below).

  

  
  
  

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

  
  

  Takeoff power is the amount of power required to lift an aircraft off the ground and into the air. Tyre design, rolling resistance, and tyre pressure can all affect an aircraft's performance during takeoff and landing, as they can impact the amount of friction between the wheels and the runway. Brake forces when landing is also important, as they help to slow the aircraft down and bring it to a stop.
  
  
  
  
  
  

  Tyre design is an important consideration for takeoff and landing. The tyres must be able to support the weight of the aircraft during takeoff and landing and be able to withstand the high temperatures generated by the friction of the tyres with the runway during braking. Rolling resistance, which is the force required to move the aircraft's wheels along the ground, is also an important factor in determining the takeoff and landing distances.

  Tyre pressure is another important consideration for takeoff and landing. The pressure must be carefully calibrated to ensure that the tyres can support the weight of the aircraft without bursting. Brake forces are also important during landing as they are used to slow the aircraft down after touchdown. The brake system must be able to generate enough force to stop the aircraft safely within the available runway distance.

  
  

  Take-off is the phase of the flight in which an airplane leaves the ground and becomes airborne. For lighter aircraft full power is given during take-off whereas, on the other hand, large cargo carrier aircraft make use of less power during take-off in order to increase the life span of an engine, reduce maintenance costs, reduce engine heat, and also a smooth take-off flight.

  -The forces involved during take-off are the following:

  T=Thrust force pushes the aircraft in the forward direction on the runway.

  D=Drag force resists the forward motion of the aircraft.

  F=Rolling resistance force when the wheel comes in contact with the ground during landing and take-off.

  -During takeoff on the runway the imbalance force will cause acceleration along the runway and it is given by the formula:

  

  -Now when the pilot is ready to take off the aircraft will accelerate to a speed that would be given by the aircraft controlling department. Then after take-off, the flight will be elevated to a certain angle and height. then it will be made to stabilize in an equilibrium manner.

  -Here safe speed or rotational speed is defined as Vr which acts as a critical factor for determining take-off performance. For safety reasons Vr is usually determined as 1.1*Vstall(the lowest speed that aircraft can be flown before the air starts to separate from the wings when the angle of attract becomes too great.

  -Vstall can be calculated by using the formula given:

  
  
  
  
  

  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.

  c.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. It is mainly caused by effects; thnon elastic at is, not all the energy needed for deformation (or movement) of the wheel, roadbed, etc., is recovered when the pressure is removed. Two forms of this are hysterisis losses , and permanent plastic deformation of the object or the surface (e.g. soil). Another cause of rolling resistance lies in the slippage between the wheel and the surface, which dissipates energy. Note that only the last of these effects involves friction, therefore the name "rolling friction" is to an extent a misnomer.

  
  
  
  

  *Tyre design of an aircraft:

  -An aircraft tyre is designed to withstand extremely heavy loads by absorbing shocks during and thereby providing a cushioning effect.

  -The number of tires required for an aircraft depends on the total weight of the aircraft as the weight needs to be distributed evenly.

  -Aircraft tyre is designed to facilitate stability in high crosswind conditions, to channelize the water away to prevent skidding, and helps to give a good braking effect.

  

  -Aircraft tires are usually inflated by nitrogen air in order to reduce expansion and contraction from extreme changes in ambient pressure and temperature. This type of inert gas will eliminate the possibility of a tire explosion.

  -Aircraft tire designs are set into an aircraft based on its application and also sufficient clearance with the ground for allowing tyre growth which happens when centrifugal force is at high speed.

  *Rolling Resistance:

  -Rolling resistance or rolling drag is the force resisting the motion when the body rolls on a surface and it is mainly caused by non-elasticity which is not all the energy needed for the deformation of the wheel is recovered when the pressure is removed.

  -The rolling resistance equation can be defined by the following equation:

  

  -Usually, aircraft have a very low rolling resistance coefficient of 0.06. Some other examples are as follows:

  

  *Tyre Pressure:

  -Aircraft tyres are designed to withstand heavy loads and shocks during landing and take-off and also need to distribute weight evenly.

  -As per research and testing it is found that aircraft tyres are able to sustain pressure up to 800 psi. Generally to note the tyre pressure of an aircraft a special type of sensor is used,its diagram is given below:

  

  -There are 2 primary parameters that are hazardous to aircraft tires:

  I)Deflation:

  Here the tire deflates in a controlled manner with a minimum direct consequence to another system.

  II)Explosive breakup:

  In this case, the tire deflates or bursts in an uncontrolled manner with a probability of causing damage to another secondary system, which further can cause a major crash-landing incident.

  *Brake forces:

  -Braking an aircraft is a challenging job for most pilots, especially during landing in a rainy and cross-wind environment.

  -In order to encounter this kind of problem pilots usually make use of spoilers and reverse thrust methods in order to have a safe landing so that the energy required to apply brakes on tires can be reduced and henceforth they do not skid.

  -Now there is a method that determines the brake force for aircraft and they are as follows:

  k=1/2mv^2, where m= mass of aircraft and v=velocity of aircraft.A typical commercial landing speed will range between 150 to 165 MPH. And for passenger flights, it is about 166 to 172mph.

Part B:

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

To calculate the force and power required to push/pull an aircraft by a towing vehicle, we need to make some assumptions:

The towing vehicle and aircraft are connected through a tow bar.
The aircraft is not moving and has a weight of 100,000 lbs.
The coefficient of rolling resistance between the tow bar and the ground is 0.03.
The towing vehicle is a diesel-powered truck with an engine efficiency of 35%.
The towing vehicle's transmission is in first gear, and the gear ratio is 4:1.
The towing speed is 5 mph.
Using these assumptions, we can calculate the force required to tow the aircraft:

Force = Weight of aircraft x Coefficient of rolling resistance
Force = 100,000 lbs x 0.03
Force = 3,000 lbs

Next, we can calculate the power required to tow the aircraft:

Power = Force x Towing speed
Power = 3,000 lbs x 5 mph
Power = 15,000 lb-ft/min

To convert lb-ft/min to horsepower (hp), we can use the following formula:

1 hp = 550 lb-ft/min

So, the power required to tow the aircraft is:

Power = 15,000 lb-ft/min / 550 lb-ft/min/hp
Power = 27.27 hp

Therefore, the force required to tow the aircraft is 3,000 lbs, and the power required is 27.27 hp.

table of the parameters you can use in Excel:

Parameter	Value
Aircraft weight	100,000 lbs
Towing speed	0-5 mph
Required towing force	3,000 lbs
Required power	27.27 hp
Motor type	DC series motor
Motor power rating	30 hp
Motor torque rating	80 lb-ft at 1000 rpm
Motor controller	DC motor controller
Rated current	150 A
Rated voltage	48 V
Battery capacity	710 Ah
Energy efficiency	80%

Please note that the values provided in this table are just examples and may not be suitable for any specific application.

The drag force acting on the tow will be :

The drag force D exerted on a body traveling though a fluid is given by

C is the drag coefficient, which can vary along with the speed of the body. But typical values range from 0.4 to 1.0 for different fluids (such as air and water)

ρ is the density of the fluid through which the body is moving

v is the speed of the body relative to the fluid

Now the tractive force or the pulling force required by the tow will be

Pulling force = Drag force + friction force + Rolling resistance force

Now let us consider aircraft with the following specifications:

Now as we have seen that various kinds of planes have different weights, the amount of pulling force also will be different. Therefore we will consider a range of weights:

Range of weight = 200 kgs - 250000 kgs '

The towing speed considered is 5 m/s

Area range : 50 - 100 m^2

Coefficient of rolling resistance: 0.02

Coefficient of friction: 0.01

Above are two figures that present the towing that is done to move the aircraft. The figure on the left represents the traditional towing method via a tow truck/tractor. The figure on the right represents an aircraft towing system (ATS) that was created by a company founded in 2003 called Mototok. The ATS' they create are considered nothing less of a revolutionary technology due to the following factors, but not limited to:

• Fully clean electric drive
• Extremely powerful electric motors – driven by high performance, maintenance-free batteries with high recycling capability
• Radio remotely controlled - only 1 person required for operation (as opposed to atleast 4 that are required for towing with a truck/tractor). The operator is able to move around to see every vantage point, ensuring high safety and reliability
• Extremely compact
• Little to no maintenance costs

Having chosen the Boeing 737-400 (68,000kg) as the aircraft to evaluate the following questions, the ATS chosen is the Mototok Twin 7500, with a max towing capacity of 75,000kg.

(Note - all numbers used are actual parameters of both Boeing 737-400 and Mototok Twin 7500, unless stated otherwise)

The ATS will need to account for the following to produce enough thrust force to tow the aircraft:

1. Rolling resistance force of aircraft
2. Rolling resistance force of ATS
3. Inertial force of aircraft
4. Inertial force of ATS
5. Drag force aircraft experiences
6. Drag force ATS experiences
   
   
   
   

Total traction force the ATS needs to produce = 13,341.6 + 412.02 + 3570 + 110.25 + 1.35 + 0.61 = 17,435.83N or approximately 17.5kN

Total traction power = Fv = 17,435.96*1.05 = 18,307.76W or approximately 18.3kW

Note: The force and power values are for both pushing and pulling the aircraft, which is not always the same. Push and pull forces are often applied at different angles (consider a box for instance), making the pull force smaller than push force. However, with an ATS towing an aircraft, both pushing and pulling are applied at the same angle, which leads to no difference in the amount of force needed.

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

To create a Simulink model, you will need to follow these steps:

• Open Simulink and create a new model.
• Add the necessary blocks to the model to represent the system being analyzed. In this case, you will need to add blocks for the towing vehicle, the aircraft, and the force and power calculations.
• Configure the blocks with the appropriate parameters, such as the force and power values calculated in the previous step, as well as the characteristics of the towing vehicle and aircraft.
• Connect the blocks to form the appropriate inputs and outputs for the system being modeled.
• Run the simulation and analyze the results to ensure that they match the expected outcomes based on the calculated force and power.

It is important to note that the specific steps and blocks required for the Simulink model will depend on the specific details of the towing vehicle and aircraft being analyzed, as well as the assumptions made during the force and power calculations.

SCRIPT FOR FIRST CALCULATION OF PREVIOUS QUESTION

%Assumptions
aircraft_weight = 100000; %lbs
rolling_resistance = 0.03;
engine_efficiency = 0.35;
gear_ratio = 4;
towing_speed = 5; %mph

%Calculation of force required to tow aircraft
force = aircraft_weight * rolling_resistance;

%Calculation of power required to tow aircraft
power = force * towing_speed;

%Conversion of power to horsepower
power_hp = power / 550;

%Displaying the force and power required
disp(['The force required to tow the aircraft is ',num2str(force),' lbs.'])
disp(['The power required to tow the aircraft is ',num2str(power),' lb-ft/min or ',num2str(power_hp),' hp.'])

Now we use a script from Matlab which will help us calculate the pulling force required:

Results:

7. A. Design an electric powertrain with the type of motor, its power rating, and energy requirement to fulfill aircraft towing application in Simulink. 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 the powertrain.

(Hint: DC7 Block)

B. Also, Design the parameters in an Excel sheet.

Assumptions:

The aircraft's weight is 100,000 lbs
The towing speed is between 0 to 5 mph
The required force to tow the aircraft is 3,000 lbs
The power required to tow the aircraft is 27.27 hp
Design steps:

Choose a suitable electric motor type and power rating that can provide the required force and power to tow the aircraft. DC series motor, rated at 30 hp, with a torque rating of 80 lb-ft at 1000 rpm, can be considered.

Select a suitable DC motor controller to control the motor speed and torque. A DC motor controller with a rated current of 150 A and a rated voltage of 48 V can be chosen.

Determine the battery capacity required to supply energy to the motor. Assuming an energy efficiency of 80%, the battery capacity can be calculated as follows:

Battery capacity = Power / (Battery voltage x Energy efficiency)
Battery capacity = 27.27 hp / (48 V x 0.8)
Battery capacity = 710 Ah

Estimate the duty cycle range to control the aircraft speed from zero to highest. Assuming a linear relationship between the duty cycle and speed, the duty cycle can be calculated as follows:
Duty cycle = (Towing speed / Maximum speed) x 100%
Duty cycle = (Towing speed / 5 mph) x 100%

Draw a block diagram of the powertrain, including the motor, motor controller, battery, and tow bar.
Please note that the above design steps and assumptions are just general guidelines, and the actual design may vary depending on the specific requirements and constraints of the aircraft towing application. It is recommended to consult with a professional engineer or expert in the field before implementing the design.

table of the parameters we can use in Excel:

Parameter	Value
Aircraft weight	100,000 lbs
Towing speed	0-5 mph
Required towing force	3,000 lbs
Required power	27.27 hp
Motor type	DC series motor
Motor power rating	30 hp
Motor torque rating	80 lb-ft at 1000 rpm
Motor controller	DC motor controller
Rated current	150 A
Rated voltage	48 V
Battery capacity	710 Ah
Energy efficiency	80%

Block Diagram of Powertrain:

Consider the powertrain with the following specifications:

SIMULATED MODEL: A full model has been simulated to present the electric powertrain of the chosen Mototok 7500NG towing a Boeing 737-400. All the above calculated parameters (sourced from actual data) and stated assumptions have been inputted to evaluate the performance of the system.

MOTOTOK 7500NG SUBSYSTEM:

BOEING 737-400 VEHICLE BODY SUBSYSTEM:

OUTPUT:

• In 120 seconds, the ATS is able to tow the aircraft for 78.22m

DISTANCE TRAVELLED:

• Since the calculations done in this project are for 20 seconds of towing at top speed, the above graph showcases the distance travelled in the final 20 seconds of the simulation, which happens at basically the top speed the ATS can travel at. In the final 20 seconds, the ATS is able to move the aircraft by 16.22m, giving a speed of about 0.81m/s. According to ATS data, it can travel at a top speed of 1.05m/s, which is not too far from our results here and is fairly accurate.

STATE OF CHARGE:

• In the 120 seconds of towing, the battery has depleted from 100 to 90%

TOTAL TOWING DISTANCE:

• The current powertrain is capable of towing the aircraft for about 1190 seconds, which is about 20 minutes before the battery is completely depleted to 0% and needs to be recharged.
• The total distance that this powertrain can tow the aircraft is about 950m in those 1190 seconds.

VELOCITY:

• The ATS reaches its top speed of about 0.82m/s at around 100 seconds, and travels constantly at that speed until the battery runs out.

Conclusion:

An electric powertrain is designed and simulated to tow a Boeing 737-400. Actual industrial data (barring the difference in motor used in the ATS) is used from verified sources and results obtained are quite close to actual data, making this quite an accurate model. The designed electric powertrain is capable of towing the craft for about 20 minutes. It reaches its top towing speed of 0.82m/s at about 100 seconds and is able to maintain that until the battery runs out. With a more powerful motor and battery system, this simulation can be further built upon to achieve even more detailed results with higher precision.

reference:

https://wiki.ivao.aero/en/home/training/mediawiki/index

https://www.faa.gov/

https://www.icao.int/