aircraft power plant system

7/27/2019 aircraft power plant system

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POWER PLANT/ENGINE

(ATA 71)

Engine Integration for MostCivil Transport

A. Wing-mounted (below the wing)

> Medium & Large Jet Airplane

B. Fuselage-mounted (at the back offuselage) > Small Jet Airplane


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Considerations:

C.G. range: B requires 30% (MAC), 10% higher than A.

Wing weight: A lower, but more complex.

Engine accessibility: A is better

Flow around wing: A disturbing

HLD: A less efficient and complex.

FOD: B is better

Nose wheel spray: A is better

Thrust reverser: A influence slats, B influence rudder.

Ground handling damage: B is better

Take-off rotation angle: B is better due to c.g. position.

Effect of in-advertent in-flight deployment of thrustreverser: B is better (flow around leading edge).

Becoming a trend for jet airplane (medium & large)

Engine Integration


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Airworthiness Requirements


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Airworthiness Requirements

25.903 Engines.(a) Engine type certificate.(1) Each engine must have a type certificate and must meet theapplicable requirements of part 34 of this chapter. (lihat fuel syst)(2) Each turbine engine must comply with one of the following:

(i) Sections 33.76, 33.77 and 33.78 of this chapter in effect onDecember 13, 2000, or as subsequently amended; or(ii) Sections 33.77 and 33.78 of this chapter in effect on April 30, 1998,or as subsequently amended before December 13, 2000; or(iii) Comply with 33.77 of this chapter in effect on October 31, 1974,

or as subsequently amended prior to April 30, 1998, unless thatengine's foreign object ingestion service history has resulted in anunsafe condition; or(iv) Be shown to have a foreign object ingestion service history insimilar installation locations which has not resulted in any unsafe

condition.


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Airworthiness RequirementsThrust Ratings

FAR 33.7(c) For turbine engines, ratings and operating limitations areestablished relating to the following:(1) Horsepower, torque, or thrust, rpm, gas temperature, and time for

(i) Rated maximum continuous power or thrust (augmented);(ii) Rated maximum continuous power or thrust (unaugmented);(iii) Rated takeoff power or thrust (augmented);(iv) Rated takeoff power or thrust (unaugmented);(v) Rated 30 minute OEI power;

(vi) Rated 2 1/2 minute OEI power;(vii) Rated continuous OEI power; and(viii) Rated 2-minute OEI power;(ix) Rated 30-second OEI power; and(x) Auxiliary power unit (APU) mode of operation.


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OperatingEnvelope


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Gasturbine is a volumetric machine


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Engine limiters


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Influence of O.A.T. on N1


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Background of Thrust Requirements

Take-off length (Table 1)

OEI performance (Rocky Mountains, Table 2)

Climb performance (Table 3, Fig. 5)

Cruise speed (Table 4) Idle rating:

flight: bleed air press, anti icing

approach: min 3.2% climb gradient after 8s. ground: max. thrust during taxi, no frequent

braking (6-7% Take-off thrust).


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Background of Thrust Requirements

Table 6.1 Take-off length


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Background of Thrust RequirementsTable 2 OEI performance


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Fig. 5Background of

ThrustRequirements

Climbperformance

(mass in 1000 lb,transition due toCAS and Mach Nr)


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Background of Thrust RequirementsTable 4 Cruise speed


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GTE Thermodynamic Cycle


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GTE Type

Turbofan

Turbojet Turboprop


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GTE: Turbofan Engine

Turbofan = Gas Generator + Fan

Bypass Ratio

h

c

m

m

B

Total Thrust:hcTTT

Low B < 2Medium 2 < B < 3High B > 3

Aft-Fan

Forward-Fan

Turbine blade extension

Bolted to the compressor

Driven by free turbine

Connected to reduction gear


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GTE: Turbofan Engine

Principles of Operation:

the basic principles of theturbofan engine operation issimilar to that of the turbojet,except in turbofan engine someof the air do not enter theengines core


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Exhaust

Consists of a jet-pipe and a thrustreverser.

When thrust reverser stowed: good engine performance

no extra base drag good engine noise attenuation

When thrust reverser deployed: no effect on operating limits good reverser performance in ground

roll good aircraft directional stab. & control no exhaust or FO ingestion


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Exhaust


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Exhaust


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Exhaust


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Noise

ICAO Annex 16, Chapter 3 Noise Regulation:Three measurement stations:

- 2000 m before beginning of runway(approach)

- 450 m aside of the runway - 6500 m after take-off roll (fly-over)

As a function of A/C weight

(B747 stage 3, Fo-28 stage 2) NAP: Noise Abatement Procedure (flight path

optimization)


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Noise Level

N i L l


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Noise Level

N i S t


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Noise Spectrum


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Noise Suppression


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Starting

Possible power sources:- Electrical motor (up to 4000 shp or 5000 lbs)

- Hydraulic motor (helicopters)

- Turbine (military)- Jet fuel starter (mini gas turbine, military)

- Hydrazine turbine motor (military)

- High pressure air turbine (200 bar)- Low pressure air turbine (2-4 bar)

> 40 pax, requires air turbine starter


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Starting


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Starting


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Starting

Subject to be considered:

- Start time (torque charact., accessory drag,starting envelope, max start time, shock

limit, available pressure) :- Clutch disengagement/reengagement speed

- Crash engagement

Restart capability

Windmill: From 20000 ft, requires no morethan 5000 ft for restarting


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StartingEnvelope


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Auxiliary Power Unit (APU)


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APU

A ili P U it (APU)


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Auxiliary Power Unit (APU)

Fuel Control


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Fuel injection system


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Oli Cooling System

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