level turn & pull-up maneuver - cdeep-iit bombay

AE-705 Introduction to Flight Lecture No 14 Capsule-07

AE-705: Introduction to Flight

Level Turn & Pull-up Maneuver

Udit VohraAerospace Engineering Department

PEC University of Technology,

Chandigarh


LAYOUT

• Coordinated Turn

• Turning flight parameters

• Fastest turn

• Tightest turn

• Turning in vertical plane


LETS FLY IN A LOOP

Watch the video carefully


Watch the water level during the turn !


COORDINATED TURN

How do they do that ?


1. Constant Altitude

2. Banking of the a/c in horizontal plane

3. No tangential acceleration

4. Turn without a sideslip

5. Coordination b/w Ailerons and Rudder

Coordinated Turn

Use of Rudder in

a turn … why ??

Rudder for

yaw and

ailerons to roll

we will see that later on

coordinated turn.mp4

coordinated turn 2.mp4


UNCOORDINATED TURN

skid

skidding.mp4


Adverse Yaw

The reason why we use rudder in a turn

http://www.boldmethod.com/learn-to-fly/aerodynamics/the-aerodynamics-of-a-turn-in-an-airplane/

Adverse Yaw.mp4


TURNING FLIGHT EQUATIONS


Equations of motion

ϕ

ϕ

L

W

LCosϕ = W ----(1)

LSinϕ = mV2

R----(2)

(2) / (1)

Tanϕ =V2

Rg

n = L

W( load factor)

n = 1 Cosϕ = Secϕ


Turning Flight Parameters

Banking Angle

Φ = Cos−1( 1 n)

Related to turn rate

Steady coordinated turn is

not possible without

banking the a/c

Load Factor (n)

n = L

W

Depends on aircraft design

parameters

Represented in g’s


turn radius

mV2

R=

WV2

g R=

W n2 − 1

R = V2

g n2−1

Turn Radius

depends on V and n

R

R


Turn rate

ω = dθ

dt=

V

R

ω = g n2−1

V

Turn Rate

depends on V and n

ω

ω

Degrees travelled per secSimilar to Angular Velocity


Effect of bank angle

Pilot’s Handbook of Aeronautical Knowledge

Bank angle in a turn results in:

• Higher rate of turn

• Smaller radius of turn

• Higher loading on the wings

• Higher stall speed


Fastest turn

• Max. turn rate

• Measure of a/c’s maneuverability

• Depends on a/c design parameters

V should be min

n should be max

Sustained turn rate when

• Thrust/weight

• Wing loading

• Aspect Ratio


Tightest turn

• Min turn radius

• Measure of maneuverability

• Depends on design parameters

V should be min

n should be max

What is Vmin and nmax ??

What are constraints on nmax

Find out yourself !

Report on Moodle

Instantaneous turn rate when

• Thrust/weight

• Wing loading

• Altitude


Continue..

http://people.clarkson.edu/~pmarzocc/AE429/AE-429-12.pdf


http://people.clarkson.edu/~pmarzocc/AE429/AE-429-12.pdf


Instantaneous & Sustained turn

• Dogfight are generally dependent on rate of turn

• Aircraft which can turn faster will get into an

advantageous firing position quickly

ITR is a measure of how quickly an aircraft is able

to turn at the beginning of the turn

The turn rate which can be maintained for a period of

time is called the STR (Sustained turn rate)

Instantaneous turn 1.mp4

Instantaneous turn 2.mp4

instantaneous turn 3.mp4


Tejas vs. F-16

v/s

Which one is better

and how?

What do you think ?


Continued..

https://www.quora.com/search?q=instantaneous+turn+of+an+aircraft

Depends on wing

loading & Thrust to

weight ratio

Tejas wing loading: 247

kg/m²

F-16C Block 50 wing

loading: 431 kg/m²

Lesser the wing

loading more will be

the ITR


At horizontal plane STR, ITR > STR

the LCA outperforms the F-16A/B at high Mach numbers

and the F-16C/D under all Mach number regimes.

http://thebetacoefficient.blogspot.in/2015/04/lca-tejas-versus-f-16-in-combat-part-i.html


Tejas v/s F-16

T:W is favorable for the F16, though the difference is smaller

(1.09 v/s 1.07 )

STR of F-16 > Tejas at slower speeds (< M = 0.65)

Tejas dominates at speeds greater than 0.65

• Dogfights generally happen at M > 0.65

• @ M < 0.65 Tejas = F-16


Outcome of a dog-fight is difficult to predict

because it depends on

• the pilot,

• the initial positions of the aircraft

• the aircraft specs.

Tejas will dominate the F-16 in a majority of engagements

based on the aerodynamic characteristics

Made in INDIA


TURNING IN VERTICAL PLANE

Source: https://giphy.com/


Turning in Vertical plane

• Aerobatic and combat a/c maneuvers

• Required during takeoff and landing

turning in vertical plane.mp4


Pull-Up Maneuver

Flight along a curved path with altitude increasing

Fr = L – W = W( n - 1)

Fr= mV2

R

R =V2

g(n−1)

ω = g(n−1)

V

pull up and pulling out of a dive.mp4


Dive Pullout

Part of descent flight

pilot_handbook_2016.pdf

• During this nose-down attitude,

the AOA and the airspeed

• The smooth flow of air over the

wing begins again, lift returns,

and the aircraft begins to fly

again.

pulling out of a dive.mp4


Team Assignment No 4

Design and Fabrication of a Glider


Design a Glider for max. Range & Endurance

Launch from third floor of Foyer in LHC

No limit on material, or dimensions

Best of two launches for each Team

Technical Report to be submitted

Relative Scoring Scheme (to be announced)

Glider Design Competition


Location of the Competition


Example


Professional flyers

How do birds turn during a flight ?

Aerodynamics of Avian Flight

No Ailerons No vertical tail

../../../../../../AA_NTU/acads/first sem/MA4878_UAV/lectures/06_MA4878_FlappingWingAerodynamics.pptx

level turn & pull-up maneuver - cdeep-iit bombay

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