Airport Planning

L28: Aircraft Characteristics

Dr. Rajat Rastogi, Associate Professor

Lecture Outline

• Aircraft characteristics

• Influence of aircraft characteristics

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Aircraft Characteristics

• Engine Type and

Propulsion

• Size of aircraft

• Aircraft weight and

wheel configuration

• Minimum Turning

Radius

• Speed

• Minimum Circling

Radius

• Capacity

• Noise

• Vortices at tail ends

• Jet Blast

• Fuel Spillage7/18/2016 11:45 AM

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Engine Type and Propulsion

• Propulsion Type –

• Piston engine, Jet engine (Turbo jet, Turbo propulsion or

Ram jet) or Rocket engine

• Speeds: 500 km/hr, 800 km/hr, 1280 – 2400

km/hr, 4600 km/hr respectively

• Altitudes low, low to middle and high altitudes

• Ram jet is used in missiles and rocket engine is

used for outside atmospheric operations7/18/2016 11:45 AM

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Engine Type and Propulsion

• Specific Fuel Consumption – Fuel required to

create thrust of 1 lb

• Factors influencing:

• Weight of aircraft

• Altitude

• Speed

• Engine’s Bypass Ratio ????7/18/2016 11:45 AM

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Size of Aircraft

• Basic parameters -

• Fuselage length (from nose to tail),

• Gear tread (distance between main gears),

• Height (at tail),

• Tail width,

• Wheel base (distance between nose gear

and main gear) and

• Wing span (near main gear)

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Size of Aircraft

Tail width

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Aircraft Weight

• Operating Empty weight (OEW) - a

• Pay-load (PL) - b

• Zero-Fuel weight (ZFW) – c = a+b

• Maximum Structural Pay-load = (ZFW – OEW)>b

• Maximum Ramp Weight (MRW): Apron to

Runway end

• Trip Fuel Weight (TFW)

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Aircraft Weight

• Maximum Gross Take-off weight (MGTOW) - d

• Maximum Structural Take-off weight (MSTOW):

at sea level, Temp. 15oC, Standard Design

Wheel weight

• Maximum Structural landing weight (MSLW): e

Weight for which landing gear is designed

• Landing weight MSLW

• Tae-off weight MSTOW

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Aircraft Weight

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d

a (66-44%) b

24 – 16%

TFW

6 – 40%

Fuel Reserve (4-6%)

c

MRWe

Aircraft Wheel Configuration

• Aircraft weight and wheel configuration

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Minimum Turning Radius

• Angle of Rotation – Angle made by nose gear with

the axis of main gear while turning

• The maximum angle of rotation is around 50 – 60o

• Point of Rotation - The point of intersection of

axis of main gear and line through axis of steered

nose gear

• The line joining the centre of rotation and the tip

of farthest wing of the aircraft is known as the

minimum turning radius

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Minimum Turning Radius

• Minimum Turning Radius

• R = WB*Tan(90 - ) + t/2

• WB = Wheel Base

• = Steering angle

• t = Wheel track

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Minimum Circling Radius

• This is the radius in space required for the

aircraft to take a smooth turn. It depends

upon

• Type of aircraft

• Air traffic volume

• Weather condition

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Speed of Aircraft

• Air Speed

• Speed of aircraft relative to the medium

(i.e. air), depending upon air density

• Indicated speed – indicated by the

instrument on board

• This is around 2 percent lower than the true

speed at each 330 m (1000ft) above sea level

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Aircraft Speed

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Aircraft Speed

• Ground Speed

• Speed of aircraft relative to the ground

• Air speed = Ground speed (+/-) wind velocity

• Mach 1 ~ equivalent to speed of sound

• Speed of sound = 33.4 T0.5 miles per hr

• T = Temperature in degree Rankine

• 1 knot = 1 naum/h (1 nautm = 6080ft = 1.15

land mile)7/18/2016 11:45 AM

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Aircraft Speed

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Aircraft Speed - Performance

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• Do-Not Exceed speed (Vne)

• Design Maneuvering Speed (Va)

• Lift-off Speed (Vlo)

• Rotate Speed (Vr)

• Decision Speed (Vl)

• Stall Speed (Vso)

• Reference Landing Approach Speed (Vref)

• Vref = 1.3 * Vso

Aircraft Capacity

• Defined as the number of passengers and

amount of cargo it can handle

• Dependent up on

• Size and design of an aircraft

• Propulsive power of aircraft

• Speed of aircraft

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Aircraft Noise

• This is a big problem in the areas where

airports are quite near to the developed areas.

• Major sources of noise are

• Engine

• Machinery (prominent during landing)

• Primary jet (prominent during take-off)

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Aircraft Noise

• Disturbances are much more sever during

take-off than during landing

• Since the inception of the jet engines, the

noise has reduced due to technological

advancement

• Aircraft noise is less damaging than road

traffic noise ????

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Vortices at Tail Ends

• Vortices are made up of two counter rotating

cylindrical masses extending along the flight

path

• These are formed near the tail ends of the

wings or tail end of the aircraft

• The velocity of wind in these vortices may be

very high

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Vortices at Tail Ends

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Aircraft Jet Blast

• This is the blast that comes out of the jet

engine at the rear of the aircraft to provide it

force for movement

• Its severity depends up on

• Height of the tail pipe from the round

• Angle of the tail pipe

• Blast fences need to be erected to control

damage

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Fuel Spillage

• Spilling of fuel occurs when the engine is shut

down or is losing speed

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Influencing Aircraft Characteristics

• Engine Type and

Propulsion

• Size of aircraft

• Aircraft weight and

wheel configuration

• Minimum Turning

Radius

• Speed

• Minimum Circling

Radius

• Capacity

• Noise

• Vortices at tail ends

• Jet Blast

• Fuel Spillage7/18/2016 11:45 AM

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Engine Type and Propulsion

• Size of aircraft

• Speed of aircraft

• Length of runway

• Weight

• Carrying capacity

• Noise nuisance

• Circling radius

• Range

• Maintenance

facilities

• Blast pads, etc.

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Size of an Aircraft

• Load carrying capacity

• Facilities like size of apron, terminal area, etc

• Wing span – taxiway width, separation

between traffic lanes, size of gate, apron size,

width of hanger gate

• Length – widening of taxiway on curves, size of

apron, hangers, aircraft capacity, width of exit

taxiway

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Size of an Aircraft

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Chūbu Centrair International Airport

Asheville Regional Airport

Size of an Aircraft

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Size of an Aircraft

• Height – height of hanger gate, etc.

• Tail width – size of parking and apron

• Wheel base – minimum radius of

taxiway

• Gear tread – minimum turning radius

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Aircraft weight and wheel configuration

• Thickness of runway, taxiway, apron

• Distribution of load through wheels

• 5% on nose gear and rest on landing gears

• Generation of revenue

• Turning

• Stability

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Minimum Turning Radius

• Radius of taxiways

• Position in the landing aprons and hangers

• Path of nose and main gears

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Minimum Circling Radius

• Separation of two nearby airports

• Adjustment of timings of landing and take-off

aircrafts

• Airport capacity

• Zoning laws relating to height of an

obstruction (in turning zone area)

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Aircraft Speed

• Reduced journey times

• Increase in frequency of operations

• Broadening of air network

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Capacity and Range

• Facilities like processing terminals

• Passenger and baggage handling

• Cargo processing

• Need of equipments

• Size of apron

• Range proportional to Payload

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Noise

• Sleep disturbances, startle

• Annoyance

• Health risks, deafness, heart attack, etc

• Loss of Concentration, attentiveness

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Vortices at Tail Ends

• Hazardous to the following aircraft due to tail

vortices and wing vortices

• Tangential velocities ~ weight of aircraft and

inversely proportional to speed

• More intense when near the airport

• Stresses at the joints with fuselage

• Pressure on or under the wings producing lifts

or drags

• Wake-turbulence classification of aircraft7/18/2016 11:45 AM

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Jet Blast

• Inconvenience, discomfort or ever injury to

passengers

• Wake velocities and hot exhaust gas may harm

nearby aircraft (if directed towards it)

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Fuel Spillage

• Seriously affects the bituminous pavement

• Slip of wheels

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