taxa_subida e curva

8/13/2019 Taxa_subida e Curva

1/22

G.Le

ng,M

EDept,NUS

4:C

limband

TurnPerformance

orhownim

bleistheaircraft?


2/22

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ng,M

EDept,NUS

Therateofclimb(R

OC)

T

herateofclim

b(ROC)istherateat

w

hichanaircraftincreasesitsaltitude

Climbrecords

h(km)time(s)

ROC(m/s)


3/22

G.Le

ng,M

EDept,NUS

Clim

bmodel

:flightpath(climb)angle


4/22

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ng,M

EDept,NUS

Resolvingforcesparallelandperpendicular

toflightpath

(velocityV)

TDW

sin

=

mdV/dt

LWco

s

=

mVd/dt

Theclimbrateisthen

d

h/dt

=

Vsin

=

or

(TD)V

=


5/22

G.Le

ng,M

EDept,NUS

T

heclimbequa

tion

(TD)V

=

dh/dt

+d[V

2/(2g)]/dt

W


6/22

G.Le

ng,M

EDept,NUS

Specificenergy

Thequantityo

ntherhsofth

eclimbequationcanbewrittenas:

dh/dt

+d[V

2/(2g)]/dt

= =


7/22


8/22

G.Le

ng,M

EDept,NUS

Example:

F104P

sc

urves

Howto

flyfrom

energy

stateAto

stateB

asfastas

possible?

A

B

Sou

rce:NASATND6398


9/22

G.Le

ng,M

EDept,NUS

C

ompariso

nF4H-1v

sF15A

F4H-1

2xJ79-GE-2Aturbojets

thrust

=2x10

,350lb(2x4,693kg)

MTOW

=

54

,600lb

(24,761kg)

T/W

=

F15A

2xF100-PW-100turbofan

thrust

=

2x25,0

00lb(2x

11,2

50kg)

MTOW

=

5

6,000lb

(25,200kg)

T/W

=


10/22

G.Le

ng,M

EDept,NUS

Ene

rgy-Mane

uverabilit

yTheory

DevelopedbyU

SAFColJohn

BoydatGeorgia

Te

chin1962

Th

esis:

Pr

ovedthattheF-4couldnotoutturnaMiG

-21

ex

ceptatlowaltitudeandhigh

speed

E-

Mtheorywas

appliedtothe

designofthe

F1

5andF16

USAF

ColJohnBoyd

1

927-1997


11/22


12/22

G.Le

ng,M

EDept,NUS

S

ustainedlevelturn

model

Lcos

=

Lsin

=

Resolving

forcesinthev

erticaland

horizontaldirections

L

:

:bankangle

d/dt:turnrate

W=

mg


13/22

G.Le

ng,M

EDept,NUS

D

efinetheload

factorn

=

L/W

=

1/cos

(n>

1)

Dividingthe2

forceequations

V/gd/dt

=

tan

= =


14/22

G.Le

ng,M

EDept,NUS

Theturnequationis:

d/dt

=

(g/V)(n2

-1)

Theturnradiusis:

R

=

V/d/dt

=

V2/(g(n2-1))


15/22

G.Le

ng,M

EDept,NUS

E

xample:

Turnenvelope


16/22

G.Le

ng,M

EDept,NUS

Exercise:

Per

formance

estimation

AssumingAhasacornervelocityof450ktsat

aloadfactorof8,whats

thetu

rnradiusand

turnrate?

AssumingBisflyingatthesame

speed,whatstheloadfactorandturn

ratef

orB?


17/22

G.Le

ng,M

EDept,NUS

Tu

rnatmax

imum

loadfactor

Question:Whatsthe

bankangle?


18/22

G.Le

ng,M

EDept,NUS

lo

adfactorn=

bank

angle=

airspeedV

=

450kts=

450*0.5151

=

232m/s

tu

rnrate

= = = =

turnradius

=

V/turnrate

=


19/22

G.Le

ng,M

EDept,NUS

RA

=

V2/(g(nA

21

))

RB

=

V2/(g(nB

21))

loadfactornB

= =

turnrate

= =


20/22

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ng,M

EDept,NUS

Comparisonofturn

rates


21/22

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BottomLine

Highturnrat

esrequirehighloadfactors

Notes:


22/22

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EDept,NUS

V-n

Diagram

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