Project-1: Powertrain for aircraft in runways

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

Answer:-

Manufactures's empty weight(MEW):-

It is known as Manufacture's Weight Empty (MEW) or Licensed empty weight.It is the weight of the aircraft "as built" and includes the weight of the structure,power plant,furnishing,installations,systems and other equipment that are considered an integral part of an aircraft,excluding any baggage,apssengers,or uasable fuel.

Zero-Fuel weight (ZFW):-

This is the total weight of the airplane and all its contents but excluding the total weight of the usable fuel on board.As a flight progresses and fuel is consumed,the total weight of the airplane reduces,but the ZFW remains constant.

Maximum zero fuel weight (MZFW):-

It is the maximum weight weight allowed before usable fuel and other specified usable agents are loaded.

Operating empty weight(OEW):-

It is the basic weight of an aircraft including the crew,all fkuids necessary for operation such as engine oil,engine coolant,water,unsable fuel and all operator items and equipment required for flight but excluding usable fuel and the payload.

Payload:-

It is the carring capacity of an aircraft.It includes cargo,people,extra fuel,In the case of commerical airliner,It may refer only to revenue-generating cargo or paying passengers.

Maximum takeoff weight (MTOW):-

This is the maximum weight at which the pilot of the aircraft is allowed to attempt to take off.

Regulated takeoff weight (RTOW):-

Depending on different factors,RTOW or maximum permissable takeoff weight varies for each takeoff.It can never be higher than MTOW.

Maximum landing weight (MLW):-

This maximum weight at which an aircraft is permitted to land.

Maximum ramp weight (MRW):-

It is the maximum weight authorized for maneuvering an aircraft on the ground.It is also called maximum taxi weight(MTW).

Aircraft gross weight:-

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

The following image depicts takeoff weight components.

Here is a list of total weight of different types of vehicles.

Aircraft Weight List

NAME	MAKE	EMPTY WEIGHT(Kg)	MAXIMUM TAKEOFF WEIGHT (Kg)
AIRLINERS
Airbus A320	Airbus	42595	79015
Boeing 747-8i	The Boeing Company	220128	447696
Boeing 777-30	The Boeing Company	159570	299370
AIR FREIGHTER
Antonav Mriya 225	Antonov	285000	640000
Antonov 124 Rusian	Antonov	181000	402000
C-5M	Lockheed Martin	172365	381018
Boeing C-17 Globemaster III	The Boeing Company	128140	265352
JETS
Cessna Citation CJ4	Textron Aviation inc.	4663	7761
Cessna Cilitation Longitude	Textron Aviation inc.	10705	17917
FIGHTER JETS
F22 Raptor	Lockheed Martin	19700	38000
F16 Falcon	General Dynamics	9207	21772
Sukhoi Su 57	Komsomolosk on Amur Aircraft Plant	1850	29270
TURBOPROPS
TBM 930	Daher	2097	3370
Cessna 208	Textron Aviation Inc.	2145	3629
Beechcraft king Air 350i	Textron Aviation Inc.	4500	7485
PROPELLER AIRCRAFT
SR22	Cirrus Aircraft	5000	7498
Xcub	Cub Crafters	2680	5070
DA40 (NG)	Diamond Aircraft	4374	6221
HELICOPTERS
Apache 64	Boeing Defense,Space & Security	6838	10432
Mi 35M	Rostvertol	8500	12000
Chinook CH	Boeing Rotorcraft Sysytems	11148	22680

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

Answer:-

• Ground speed is defined as Aircraft relative speed to the surface of earth.
• Air speed is defined as the relative speed of the airplane to the speed of the air in which it is flying.
• Air speed 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.it can be said as,

Ground speed=Air speed+Wind speed

(or)

Air speed=Ground speed-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 travelling in,The aircraft expreiences headwind,and its ground speed is lower than its airspeed.

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

Answer:-

Although Aircrafts can use the engine to move around in the airport but it is not recommended to use aircraft engine power.Here are some reasons why,

• Line of sight:-On moving the aircraft,the pilot need to steer it.The pilot sitting in the cockpit has his eye level at around 5.5m above ground,which creates a big blindspot a head of him.So,for moving on the ground,planes do not use engine power and rely on towing crew.
• Reverse Gear:- Unlike vehicles on the ground,planes don't have reverse gear.So,to get to the runway from the airport gates,they need assistance of pushback tractos.
• Safety Hazard:- Even thiugh airplanes can use engine thrust to move in airport,it has some serious disadavantages.The thrust of the engine is very loud and it has the caoacity to damage the airport buildings.Also they can suck any debris or sand into the engine which can potentially damage the engine.
• Fuel Efficiency:- Aircraft burns too much fuel and responsible for huge amount of pollution.The aviation fuel is also not cheap.So,to save some cost and fuel,it is recommended not use engine power in airport.Some airlines also suggesting the use of tractors all the way to the run way.

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

Answer:-

The process of pushing an aircraft backwards away from its parking position,Usually from at an airport gate by external vehicles is called pushback.The vehicles used for this purpose is called pushback tractors or tuhs.They are powerful and low profile.

Even though many aircrafts now a days can move backwards but they don't do so,as it has adverse effects both on the aircrafts and people nearby.Hence,pushback is preferred to handle aircraft on ground.

When the people and baggage is loaded in the plane,the pushback tugs faciliate their movement to taxiway or runway.Once the pilot gets clearance,he then communicates with the tractor driver to start the pushback.the tug may directly arrach the planes gear with the help of the tow bar,or it could be a wheel lift tug.In towrbar-less process,they scoop up the nose of the landing gear & lift it off the ground.This removes the complexity of maintaing a towbar on ramp and also saves time of connecting and disconnecting towbars.

The stopping is done by the pushback tugs.Once the push back is complete,the plane then approach the runway using the taxiways using its own power.

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

Answer:-

Take off Power:-

It is defined as the amount of power that an engine is allowed to produce for a limited period for take-off.Take off power with respect to reciprocating engines,means the brake horse power that is developed under standard sea level condiations,And under the maximum condiations of crankshaft rotational speed and engine manifold pressure approved for the normal takeoff,and limited in continues use to the period of time shown in the approved engine specification and with respect to turbine engines,means brake horsepower that is developed under static condiations at a specified altitude and atmospheric temperature,and under the maximum condiations of rotor shaft rotational speed and gas temperature approved for the normal takeoff,abd limited in continuoes use to the period of time shown in the approved engine specification.

Tyre Design:-

The aircraft tyres are designed to withstand extremely heavy loads while landing,takeoff,taxing,and parking.With increase of the weight of the aircraft,more number of tyres are required to evenly distribute the weight.

Design and Construction of aircraft tyre:-

Carcass plies also known as casing piles are used to form the tyre.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 stooped of an aeroplane.
• Tyre also helps to absorbthe shock of landing and provide cushioning the roughness of take-off roll-out,and taxi operations.

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

Rolling Resistance:-

Rolling resistance is the force that resists the motion of a body when it rolels on a surface.It is mainly caused ny mom-elastic effects,That is ,not all the energy needed for deformation of the wheel,roadned etc.,is recovered when the preasure is removed.The rolling resistance force is given by-`Frr=murr*mg`

Where ,

`murr`= Coefficent of rolling resistance,

m=mass of the body,

g=gravitational constant.

Tyre pressure:-

Air craft tires usually operate at high preasurees,upto 200 psi(14 bar,1400kPa) fpr airlines,and even higher for business jets.The main landing gear on the Concorde was inflated to 232 psi(16.0bar),while its tail bumper gear tires were inflated at high pressure of 294 psi.

Aircraft tires are usally inflated at high preassure to sustain the heavy loads during take-off,landing,taxing and parking.the tires are inflated with nitrogen to minimum expansion and contraction from ectreme changes in ambient temperature and pressure experienced during flight.They are typically made of nylon,and more recently a varienty known as armid.

Brake Force when landing:-

Stopped an aircraft landing at over 150 mph speed is not easy task.Aircraft rely on braking sysytems for safe landing on runways.For example an Airbus320 weighing around 75 tones,has a landing speed of 150 ti 160 mph.After touching the ground the aircraft must push their brakes cautiously to bring it to halyt.

Braking aircrafts is archived by:

1. Wing Spoilers:-Most aircrafts use their wing spoilers to assists braking while landing.the spouilers are extendable flaps at the ends of wings.Pilots raise the spoilers to decceleration upon reaching the runway and kept raised till the plane comes to hait.The raised spoilers increases drag that slows down the plane.

2.Disc brakes:- Aircraft also has disc braking systems just like vehicles in the ground.By design,disc brakes are static and they don't rotate with the rotor of landing gear.The disc braking system consistes of a pair of callipers that,When engaged squeezes the pads against the rotors of the landing gear,It slows down wheels,Which in turn reduces speed of the aircraft to reach a halt.Disc brakes are an essential componet of aircraft.

3.Reverse Thrust:-Many jet airplanes use reverse thrust for braking during landing.It reverse the direction of engine thrust.Generally thrust projects air out of the rear to move the plane forward.So in order to stop,thrust is projected out in the front.This is very effective is slowing down the aircraft after touch down.

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.

Answer:-

A).

To calculate the force and power required to push or pull an aircraft by a towing vehicle,fallowing assumptions are made-

Let, a Boeing n747-8i is being towed by a towuing vehicle at a speed of 6 mph.

For,Boeing 747-8i

Gross vehicle weight,m1=447696 Kg

`mu=0.013`(general value for asphalt/tarmac)

Height=19.5 m

Width=6.1 m

Drag co-effeicent,

Cd=0.031

For the Towing vehicle,

Gross vehicle weight,

m2=40000 Kg,

`murr`= 0.013

Cd=0.5

Operating speed,

v=6 mph=2.683 m/s

Using these parameters total force and power is calculated below.

Force and Power Calculate of Traction Tug

A	Rolling Resistance Calculation	Boeing 747-8i
	Total Weight of aircraft	447696
	Total weight of Towing vehicle	40000
	Gravitational constant	9.81
	Co-efficient of Rolling Resistance	0.013
	Total Rolling Resistance force(N)	62195.87088
B	Air Drag Force Calculation
	Air Density (kg/m3)	1.225
	Width(m)	6.1
	Height(m)	19.5
	Frontal area (m2)	118.95
	Air drag co-efficient for Aircraft	0.031
	Air drag co-efficient for Towing vehicle	0.5
	Operating speed (mph)	6
	Operating speed(m/s)	2.683333333
	Total Air drag Force (N)	278.5571509
	Total Tractive Force(N)	62474.42803
	Toatal Tractive Power (Push/Pull) KW	167.6397152

Note:-

Hill climb force is not calculated as most airport are pretty much flat surfaces.

So,The total tractive force is 62474.42 N or 62.474 kN.And to perform push/pull of the aircraft at 6 mph speed the tractive power of the towing vechile should be 167.64 KW.

B).

A simulink Model is created to for calculation of force and power of an Towing vehicle.All the data are assumed as done in the above question 6 A.Block diagram of the model is added below.

Upon enetering the data similiar results are archived as above calculations.

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.

Answer:-

A).

To design the powertrain for towing operation,Similar condiations are considered as discussed in the above queastion.

The total tractive power force to push/pull the aircraft,Fte=62474.42 N

Total tractive power at operational speed of 6 mph,Pte=167.64 KW

Now,Lets assume the radius of tyres of the pushback tug is,r=0.765 m

Gear ratio,G=8,

Transmission efficiency,`mum=92%,`

Therefore,The total torque at the wheels would be=Fte*r=62474.42*0.765=47792.9 Nm

So,Motor torque = Wheel torque/`(G*mut)=(47792.9/(8*0.9))=6638 Nm`

If we consider motor with 92% efficiency,Then the total power required would be=`(Pte)/(mum)`=167.64/0.92 = 182.2KW

Speed of the motor=(power/torque)=(182.2*1000/6638)*9.5493 rpm=262 rpm

Assuming the towing process lasts for 20 miniutes(0.33 hr)then,total energy consumption = 182.2*0.33=60.7 KWh

So,looking at the fig,We can use a 3 phase induction motor of rating 200 KW

The diagram of the model is shown below:-

Therefore,An induction motor with 200KW rated capacity can be used for this purpose.Also,for energy we can use 75 KWh battery packs that are seen in the EVs(mostly tesla vehicle).

Block diagram of powertrain:-

B).

The designed parameters in below is shown;

Force and Power Calculate of Traction Tug

A	Rolling Resistance Calculation	Boeing 747-8i
	Total Weight of aircraft	447696
	Total weight of Towing vehicle	40000
	Gravitational constant	9.81
	Co-efficient of Rolling Resistance	0.013
	Total Rolling Resistance force(N)	62195.87088
B	Air Drag Force Calculation
	Air Density (kg/m3)	1.225
	Width(m)	6.1
	Height(m)	19.5
	Frontal area (m2)	118.95
	Air drag co-efficient for Aircraft	0.031
	Air drag co-efficient for Towing vehicle	0.5
	Operating speed (mph)	6
	Operating speed(m/s)	2.683333333
	Total Air drag Force (N)	278.5571509
	Total Tractive Force(N)	62474.42803
	Toatal Tractive Power (Push/Pull) KW	167.6397152
	Motor efficiency	0.92
	Wheel radius of the Tug(m)	0.765
	Gear ratio	8
	Transmission efficiency	0.9
	Torque N.m	47792.93744
	Motor torque(Nm)	6637.907978
	Req.tractive power (to be produced) KW	182.2170818
	Speed of the motor (rpm)	262.1376471