Challenge

Project-1: Powertrain for aircraft in runways

PPrathamesh Shriramchandra Joshi21 Jan 2023

Part A:

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

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

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

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

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

Part B:

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

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

7. A. Design an electric powertrain with type of motor, it’s 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 powertrain.

(Hint :DC7 Block)

B. Also, Design the parameters in excel sheet.

NOTE:

Provide your Matlab code in the answer body itself.Paste the Screenshots of answer/plots/etc. in the answer body
upload relevant files (excel, txt, mat, .xlm, .m whatever required).
Add proper comments to the code wherever required for justification.
Plagiarism (copy) will result in 0 grading (if beyond 70%). The TSE might ask on-the-spot questions to determine if the submission is yours or Not.

There are many factors that lead to efficient and safe operation of aircraft. Among these vital factors are proper weights and balance control.

The maximum allowable weight for an aircraft is determined by design considerations. The manufacturer provides the aircraft operator with the empty weight of the aircraft and the location of its empty weight center of gravity (EWCG) at the time the certified aircraft leaves the factory.

The maximum design taxi weight or maximum design ramp weight (MDRW) is the maximum certificated design weight for aircraft ground manoeuvres as limited by aircraft strength and airworthiness requirements.

maximum taxi weight (MDTW OR MTW):

The difference between the maximum taxi/ramp weight and the maximum take-off weight (maximum taxi fuel allowance) depends on the size of the aircraft, the number of engines, APU operation, and engines/APU fuel consumption, and is typically assumed for 10 to 15 minutes allowance of taxi and run-up operations.

maximum design take off weight (MDTOW OR MTOW) :

The maximum design takeoff weight is the maximum certificated design weight for takeoff run as limited by aircraft strength and airworthiness requirements.

maximum design landing weight (MDLW OR MLW) :

The Maximum design landing weight is the maximum certificated design weight for landing limited by aircraft strength and airworthiness requirements. It generally depends on the landing gear strength or the landing impact loads on certain parts of the wing structure.

MDTW>MDTOW>MDLW

air craft gross weight :

It is the total aircraft weight at any moment during the flight or ground operation. This decreases during flight due to fuel and oil consumption.

The gross weight of the wehicle is gives in the maximum take off weight of the vehicle

The total weight W of the aircraft is simply the sum of the weight of all of the individual components.

W = w(fuselage) + w(wing) + w(engines) + w(payload) + w(fuel)

various types of aircrafts. :

There are a number of ways to identify aircraft by type. The primary distinction is between those that are lighter than air and those that are heavier than air.

lighter than air :

Aircraft such as ballons, nonrigid and dirigibles are designed to contain within their structure a sufficient volume that, when filled with a gas lighter than air (heated air, hydrogen, or helium), displaces the surrounding ambient air and floats, just as a cork does on the water. Balloons are not steerable and drift with the wind.

hot ballons are mostly around 70kg of weight without passengers.

Heavier than air :

This type of aircraft must have a power source to provide the thrust necessary to obtain lift. These are usually a flat-surfaced structure, often with a stabilizing “tail,” attached by a bridle to a string that is held in place on the ground. Lift is provided by the reaction of the string-restrained surface to the wind.

Heavier than air aircraft, or aerodynes, include autogyros, helicopters and gyrocopters, and conventional fixed-wing aircraft (aeroplanes).

Helicopters can weigh from 600 lb/275 kg all the way up to 123,400 lb/56,000 kg .

Another type of unmanned aircraft is the unmaned aerial vehicle (UAV), commonly called drones or sometimes remotely piloted vehicles (RPVs). These aircraft are radio-controlled from the air or the ground and are used for scientific and military purposes.

Typically helicopters weights vary from 270kg to 50000 kgs.

civil aircrafts :

All nonmilitary planes are civil aircraft. These include private and business planes and commercial airliners.

Private aircraft are personal planes used for pleasure flying, often single-engine monoplanes with nonretractable landing gear.

They can be very sophisticated, however, and may include such variants as: “warbirds,” ex-military planes flown for reasons of nostalgia, ranging from primary trainers to large bombers.

The below are the diffrenrt air crafts and their weights :

Aircraft	Empty Weight	Max Fuel Weight	Max Cargo Weight	Max Gross Takeoff Weight
Antanov AN-225	628,000 lbs 285,000 kg	661,400 lbs 300,000 kg	417,000 lbs 190,000 kg	1,411,000 lbs 640,000 kg
Airbus A380-800	611,000 lbs 277,000 kg	560,000 lbs 254,000 kg	185,000 lbs 84,000 kg	1,268,000 lbs 575,000 kg
Boeing 747-800	485,300 lbs 220,100 kg	427,400 lbs 194,000 kg	295,000 lbs 134,000 kg	987,000 lbs 447,700 kg
Airbus A340-500	370,000 lbs 168,000 kg	386,300 lbs 175,000 kg	119,000 lbs 54,000 kg	820,000 lbs 372,000 kg
Boeing 777-300ER	370,000 lbs 168,000 kg	320,800 lbs 145,500 kg	148,000 lbs 67,100 kg	776,000 lbs 352,000 kg
Boeing 787-10	299,000 lbs 135,500 kg	223,500 lbs 101,500 kg	126,300 lbs 57,300 kg	560,000 lbs 254,000 kg
Boeing 737-900	98,500 lbs 44,700 kg	53,100 lbs 24,000 kg	44,600 lbs 20,200 kg	187,000 lbs 85,000 kg
Airbus A320-100	93,900 lbs 42,600 kg	48,700 lbs 22,100 kg	44,000 lbs 20,000 kg	150,000 lbs 68,000 kg
Embraer 190	63,500 lbs 28,800 kg	28,600 lbs 13,000 kg	28,800 lbs 13,100 kg	106,000 lbs 48,000 kg
Gulfstream G650	54,000 lbs 24,500 kg	48,200 lbs 21,900 kg	6,500 lbs 3,000 kg	100,000 lbs 45,200 kg
Bombardier CRJ900	48,160 lbs 21,850 kg	19,600 lbs 8,900 kg	6,075 lbs 2,760 kg	80,500 lbs 36,500 kg
Bombardier Q400	39,300 lbs 17,800 kg	11,700 lbs 5,300 kg	18,700 lbs 8,500 kg	62,000 lbs 28,000 kg
Learjet 75	13,900 lbs 6,300 kg	6,060 lbs 2,750 kg	2,900 lbs 1,300 kg	21,500 lbs 9,700 kg
Cessna Citation CJ4	10,300 lbs 4,700 kg	5,800 lbs 2,650 kg	2,200 lbs 1,000 kg	17,200 lbs 7,800 kg
Beechcraft King Air B100	7,100 lbs 3,200 kg	3,200 lbs 1,450 kg	4,150 lbs 1,900 kg	12,000 lbs 5,400 kg
Diamond DA50 RG	3,200 lbs 1,450 kg	340 lbs 155 lbs	1,250 lbs 560 kg	4,400 lbs 2,000 kg
Beechcraft Bonanza G36	2,500 lbs 1,150 kg	450 lbs 200 kg	850 lbs 385 kg	3,660 lbs 1,660 kg
Cessna 206H	2,200 lbs 990 kg	520 lbs 235 kg	1,150 lbs 520 kg	3,600 lbs 1,630 kg
Sirrus SR22	2,250 lbs 1,000 kg	485 lbs 220 kg	950 lbs 430 kg	3,600 lbs 1,630 kg
Cessna 172R	1,700 lbs 770 kg	380 lbs 170 kg	560 lbs 255 kg	2,425 lbs 1,100 kg

Ground speed :

Ground speed is how fast an airplane is traveling, relative to a fixed point on the ground. Think of it this way: Ground speed is how fast an airplane's shadow would move across the land. If there's a strong wind pushing an aircraft, that's reflected in the ground speed.

air speed :

Airspeed, in contrast, is how fast an airplane is really flying strictly under its own power, which is calculated by subtracting the wind speed from the ground speed

The aircraft operates on both ground as well as in the air so we need to obsreve how these speeds are related.

The ground speed and air speed are usually depend on the wind speed.if the wind speed changes these speeds may change.

if we consider there is no wind speed then the air sped is equal to the ground speed .

If the wind is flowing in the same direction of the flight then (air speed < ground speed ) so air speed =ground speed -wind speed.

If the wind is flowing in the opposite to direction of the flight then (air speed > ground speed ) so air speed =ground speed+wind speed.

Taxiing :

Taxiing refers to the movement of an airplane while on the runway

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.

Although many aircrafts moves in back ward using reverse thrust as a result

The jet blast or prop wash might damage the terminal billding and other eqiuipment .

Engine close to ground may aliso damage the engine.

THis may cause the huge damage to the aircraft.

Thats why pushback trucks are provided for the backword movement of crafts in airports.

A push back truck lifts the front wheel of the aircraft .

Their (push back truck )role is to move the aircraft away from the parking area .

During high power engine running damage can occur itself to the aircraft

It is easier to the truck driver to to see the outside and drive the vehicle compared to the pilot.

The push back driver konows well about the airport compred to pilot.

The another main thing is it saves the huge fuel for such a small thing

These may damge the aircrafts which are next to it in reversing by it self.

Huge risk of jet blast and sourrounding buildings,

The aircraft is in parking place before it goes to the runway the thing is when it needs to fly it needs to come back to the runway to fly.

The aircraft can itself move backwords although it is risky for the aircraft and the sourroundings it useses the towing system.

Towing :

The forward movement of an aircraft, usually with engines off, using the power of a specialised ground vehicle attached to or supporting the nose landing gear. It may occur for the movement of both in service and out of service aircraft.

Before the aircraft to be towed is moved, a qualified person must be in the flight deck to operate the brakes in case the tow bar fails or becomes unhooked. The aircraft can then be stopped, preventing possible damage.

Towing aircraft can be a hazardous operation, causing damage to the aircraft and injury to personnel, if done recklessly or carelessly. ... The aircraft can then be stopped, preventing possible damage. Some types of tow bars available for general use can be used for many types of towing operations.

After the vehicle is taken to run way it uses taxing to move the aircraft on the runway.

Taxiing :

Taxiing refers to the movement of an airplane while on the runway

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.

Take off power :

Take is the situation where the vehicle leaves ground and enters into the air.

Initially the aircraft runs on runway for tipical time reach the max speed and to get into the air.

The more power is required to take off but the thing we should consider the engine performance for better operation and life .

On take-off, in order to position the aircraft to a safe height away from terrain and obstacles (i.e. a flight path of maximum height and minimum ground distance desired), the engine thrust is set to a high ‘take-off power’ setting (although this is not necessarily full power) and the aircraft attitude is pitched up to maintain a specific speed (usually in the region of V2 + 15kts).

Once the ‘safe height’ is reached the engine thrust can therefore be reduced to a more appropriate (i.e. efficient) setting and the aircraft flight path can be changed to a more appropriate (i.e. efficient) flight path.

In order to achieve that described above and also to provide minimum noise disturbance to the area surrounding the airport, regulatory procedures require aircraft to fly one of the two profiles given below during every departure.

Tyre design :

When it comes to saftey tyres are one of the most important components of aircraft.
They help to absorb the shock of landing and provide cushioning. It also provides the necessary traction for braking and stopping of an aircraft.
An aircraft tyre is designed to withstand extremely heavy loads while landing, take off, taxing, and parking.
The number of wheels required for aircraft increases with the weight of the aircraft, as the weight of the aeroplane needs to be distributed more evenly.

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

The carcass ply is comprised of thin textile fiber cables that are bonded into the rubber. These fiber cables are largely responsible for determining the strength of the tire.

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.

some of the techincal asspects of the air craft tyre :

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.

Tube or tube less : Tubeless tyres are more advantageous over tube-type. There is no longer the use of tube-type tyre in recent aviation. Nowadays all airliners are using tubeless tyres. Tubeless that are meant to be used without a tube has the word TUBELESS on the sidewall of the tyre.

Rolling resistance :

as we know that the force offered to the tyre .This is the force offred to the tire of the aircraft.

It depends upon the tire pressure ,tire material ,temparature around the tyre,structure of the tyre.

we that the force required to overcome the rolling resstance is given by

Frr=μrr*m*g

where,

μrr=coeficient of rolling resistance

m=mass on the tire

g=gravitational constant

Tire pressure :

The amount of air inside the tyre is known as tire pressure .

Tyre pressure makes a major role vehicle dynamics .

If the tyre pressure is less the rolling resistance force applied on the vecle will be more .

μrr=coeficient of rolling resistance

as the tire pressure decrese the μrr will increse this will increse the rolling resistance force so it leads to more energy requirement.

So the vehicle can't achive the high speed . and it tyres can't sustain the total weight of the vehicle.

coming to the aircrfts these should withstand for high load weight and high speeds on runway .

The typical airliner tire can handle a 38-ton load. It can meet the ground 500 times before needing a re-tread, a refresh it can take on seven times in its life.

Brake forces when landing :

As the aircraft lands with high speed it requires huge amount of force.

This speed should be controlled by suitable brakes withot damage or effects .

Brakes work by dissipating energy as heat through the action of friction. An aircraft wheel rotating at speed possesses a large amount of kinetic energy. By contacting the wheel with a semi-metallic or ceramic brake pad, an enormous amount of heat is generated as a result of the friction between the two contacting surfaces.

The large frictional forces generated during braking cause the pads to wear and so careful inspection and maintenance of the system is required to ensure the brakes continue to operate as designed.

Brakes are usually hydraulically actuated, but in some cases may be operated through a mechanical actuation system.

Traditionally, brakes are fitted to the upper half of the rudder pedals and are actuated through the pilot applying pressure to the top of each pedal. This toe-brake configuration is widely used and allows the pilot to apply differential braking by varying the pressure applied on each toe brake.

Many smaller light sport aircraft do not make use of toe brakes, preferring to use a simpler single lever mechanism.

There are several types of brakes for aircraft :

Disc brakes :

Disc brakes are the most common braking system in use today and consist of a disc which rotates with the wheel and a stationary brake calliper which actuates onto the disc to affect a braking force. The calliper is the name given to the assembly that contains the brake pads and piston(s). The pads are connected to the piston which actuates under hydraulic pressure applied either through a toe brake or a brake lever in the cockpit.

Expander tube brakes :

An older technology used predominantly on aircraft manufactured between 1930 and 1950, expander tube brakes are a low-pressure braking system that has now largely been replaced by disc brakes. The basic design consists of a lightweight frame attached to the outer section of a rubber tube. The frame and tube sit inside a wheel drum and a number of brake blocks are attached to the frame which provides the braking surface. The rubber tube is inflated during braking which pushes the brake pads onto the inside of a wheel drum, generating the friction necessary to slow the aircraft.

To propell any vehicle we need to overcome several opposite forces acting on the same vehicle .

The actual forces acting on the vehicle varies from place to place.

Let us consider the regular runway the oposite forces are acting to propel the vehicle are

Rolling resistance force (Frr)

and aerodynamic drag force.(Fad)

there is no grade so hill climbing force (Fhc)is neglected.

The sum these forces is actual or total force (Fte) to overcome to propel the vehicle.

Frr=mgμrr;

Fad=1/2*ρACdv^2;

where,

m-mass of the vehicle(kg)

g-gravitational constant.(kg/m^2)

μrr-rolling resistance

ρ-air density(kg/m^3)

A-frontal area(m^2)

Cd-aero drag coefficient

v-velocity of the vehicle(m/s)

Fte=Rolling resistance force (Frr)+aerodynamic drag force.(Fad)

Fte=mgμrr+1/2*ρACdv^2

assume any vehicle(aircraft ):

some of the asumptions are :

mass of the aircraft (ma)=24500kg;

mass of the towing vehicle=10000kg;

gravitational constant(g)=9.81m/s^2;

rolling resistance(μrr)=0.05;

air density(ρ)=1.5kg/m^3;

frontal area (A)=10m^2;

aero drag coefficient(Cd)=0.4+0.2=0.6;

velocity(v)=21.6km/hr=6m/sec

Frr=mgμrr

=(24500+10000)*9.81*0.05

=16922.25N

Fad=1/2*ρACdv^2

=0.5*1.5*10*0.6*6^2

=162N

Fte=mgμrr+1/2*ρACdv^2

=16922.25N+162N

=17084.25N

force required to pull or push the vehicle Fte=7909.9488N

torque at the wheels =force *radius

=17084.25*0.2(tire radius=0.2m)

=3416.85Nm

power required to pull the vehicle;

we know;

power(p) =force *velocity

=Fte*v

=17084.25*6

=102505.5watts

=102.505kw

The power required to propell the vehicle is 102.505kw.

6b.The model for the calculated force and power using Simulink :

The following are the equations modeled in simulink

Frr=mgμrr;

Fad=1/2*ρACdv^2;

Fte=mgμrr+1/2*ρACdv^2

power(p) =force *velocity

The simulink is one of the best tool for doing mathamatical model calculations .

The model consists of differnet blocks like constant ,gain ,product, squre ,dispaly blocks.

constant block : This block is used to declare the diffrent input like

m-mass of the vehicle(kg)

μrr-rolling resistance

ρ-air density(kg/m^3)

A-frontal area(m^2)

v-velocity of the vehicle(m/s)

Gain block : This block is multiply the input with the gain value.

This block is used for

g-gravitational constant.(kg/m^2)

Cd-aero drag coefficient

Display : which results the output of the equations ie, forces and power.

Tags : Used to tag the data between the blocks.(goto &from)

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

Here i assumed the rafale fighter aircraft

motor selection for the power train :

Based on some of the parameters i selected the dc machine for the power train

power rating, and energy requirement to fulfill aircraft towing application :

From the forces acting on the vehicle we calculated the power required the vehicle.

The power required to propell the vehicle is 102.505kw.

This power is the output power of the motor.

In order to select the power rating of the machine we need to consider the efficiency accepct .

Because the machine consists of different types of losses .

we know that

input power =outpower +losses in machine

efficiency (η)= outpower/inputpower

let us assume the machine efficiency is 85%

then the input power is calculated as

inputpower =outpower/efficiency (η)

=102.505kw/0.85

=120.59kw

From this we can select a 120kw dc motor is sufficient for the powerr train.

If we consider the particular motor to operate for a 1hr then the energy for the machine is given by

energy =power *time =120.59*3600

=434.124kwh or 434124wh

Duty cycle range to control the aircraft speed from zero to highest Block diagram of powertrain :

To operate the machine at high speed the it needs max power the duty cycle will be

duty cycle=outpower /input power

=102.505/120.59

=0.85%

Block diagram of powertrain :

The power train block diagram maainly consists of ;

battery

motor

motor controller

power coverter

transmission

Assumed parameters :

Here i assumed the rafale fighter aircraft ;

parameter	assumption
mass of the aircraft (ma)	24500kg
mass of the towing vehicle	10000kg
rolling resistance(μrr)	0.05
air density(ρ)	1.5kg/m^3
frontal area (A)	10m^2
aero drag coefficient(Cd)	0.6
velocity(v)	21.6km/hr=6m/sec
gravitational constant(g)	9.81m/s^2