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MSRSAS - Postgraduate Engineering and Management Programme - PEMP

Performance, Stability and Control

ii

Declaration Sheet

Student Name Sumit Kumar Malik

Reg. No BZB0413004

Course M. Sc. [Engg.] in Aircraft Design Batch Part-Time 2013.

Batch PT-2013

Module Code ACD2509

Module Title Aircraft Performance, Stability and Control

Module Date 11thOct. 2014 to 06thDec. 2014

Module Leader Mr. M. Sivapragasam

Declaration

The assignment submitted herewith is a result of my own investigations and that I have

conformed to the guidelines against plagiarism as laid out in the PEMP Student

Handbook. All sections of the text and results, which have been obtained from other

sources, are fully referenced. I understand that cheating and plagiarism constitute a

breach of University regulations and will be dealt with accordingly.

Signature of the student -sd- Sumit Kumar Malik Date 06th Dec. 2014

Submission date stamp(by ARO)

Signature of the Module Leader and date Signature of Head of the Department and date


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iii

Abstract

____________________________________________________________________________

Aircraft performance, Stability and Control module gives us an insight about how to evaluatethe performance of an aircraft in steady state in detail. The module also teaches how to control

the Performance by the use of trims in order to active the desired Stability of the aircraft and

also gives us various parameters which are used to limit of the flight envelope based on various

standard performance parameters like Wing loading, thrust to weight ratio, coefficient of drags

etc.

Part A of the assignment is to critical examine the traditional metrics are insufficient for

analyzing the combat capability of a fighter aircraft with respect to that of the new agility

metrics. It gives a summary of classification of agility metrics and the key parameters in these

metrics with actually improve the agility of a fighter plan in a combat scenario. It also describes

how the aircraft designer achieves this enhanced agility right from the starting of designing a

new aircraft.

Part B of the assignment is to develop a Matlab code, which is attached in the appendix,

which intern will be used to calculate the performance parameters. The code is used to evaluate

the performance parameters of an aircraft like it should be able to evaluate power required,

power available, maximum velocity, stall velocity, turn rate, radius of turn, longitudinal

stability, endurance and range of jet and propeller driven aircrafts. The program evaluate all the

above performance parameters considering the steady state environment by varying typical

parameters like wing loading, thrust to weight ratio individually and together at different

altitudes and generates the surface plots which are compared with thexxxaircrafts published

results.

Part C of the assignment is to use the same code which is developed for part B and then it

will be used to evaluate the performance of the yyyfighter aircraft. And then comment on the

performance obtained by using the code and the actual performance which are published by the

aircraft manufacturer. It should be noted here that a few of the performance parameters are not

published by aircraft manufacturer so they are assumed and the assumption and its rational are

mentioned wherever this short of assumptions are main in this part are used.


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iv

Contents____________________________________________________________________________

Declaration Sheet ................................................................................................................... ii

Abstract ................................................................................................................................. iii

Contents ..................................................................................................................................iv

List of Tables ........................................................................................................................... v

List of Figures ........................................................................................................................vi

List of Symbols .................................................................................................................... vii

1.

Agility ............................................................................................................................. 8

1.1. Traditional metrics for performance: .......................................................................... 8

1.2.

Agility metrics classification: ..................................................................................... 8

2. Matlab Code .................................................................................................................. 11

2.1

Performance Parameters: .......................................................................................... 11

2.2 Power Required: ........................................................................................................ 11

2.3

Power Available: ....................................................................................................... 11

2.4

Maximum Velocity: .................................................................................................. 11

2.5 Stall Velocity: ........................................................................................................... 13

2.6

Range of Jet engine aircraft: .................................................................................... 13

2.7 Range of Propeller driven engine aircraft: ............................................................... 13

2.8

Endurance of Jet engine aircraft: ............................................................................. 13

2.9 Endurance of Propeller driven engine aircraft: ........................................................ 13

2.10

Rate of climb: ............................................................................................................ 13

2.11 Glide performance: ................................................................................................... 14

2.12

Takeoff field length: .................................................................................................. 14

2.13 Landing field length: ................................................................................................. 14

2.14

Turning rate: .............................................................................................................. 14

2.15 Turn radius: ............................................................................................................... 14

2.16

Longitudinal static stability: ...................................................................................... 14

3. Performance Comparison ............................................................................................. 15

3.1

Range of Jet engine aircraft: ..................................................................................... 15

3.2

Range of Jet engine aircraft: ..................................................................................... 16

3.3 Endurance of Jet engine aircraft: .............................................................................. 16

3.4

Rate of climb: ............................................................................................................ 16

3.5 Glide performance: ................................................................................................... 16

3.6

Takeoff field length: .................................................................................................. 16

3.7 Landing field length: ................................................................................................. 16

3.8

Turning rate: .............................................................................................................. 163.9 Turn radius: ............................................................................................................... 16

3.10

Effect of varying W/S and T/W on turn and take off performance: ......................... 16

3.11 Longitudinal static stability from wing and tail: ....................................................... 16

References ............................................................................................................................. 18

References 29

Bibliography 31

Appendix-Matlab program with pictures 33


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v

List of Tables

____________________________________________________________________________

Table No. Title of the table Pg.No.

Table 1.1 ,POIJhgfhhg Error! Bookmark not defined.

Table 2.1 djfhdslfiudlfbdfiufid Error! Bookmark not defined.

Table 3.1 jfhdliufgdfdiugfpfid 16

Table 4: Error! Bookmark not defined.


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vi

List of Figures

____________________________________________________________________________

Figure No. Title of the Figure Pg.No.

Figure 1.1 serersedtytrhd Error! Bookmark not defined.

Figure 2.1 fdghgfh Error! Bookmark not defined.

Figure 3.1 ffjghfdiguhfdiugh 17

Figure 4: Error! Bookmark not defined.

< The Figure numbers have to be based on the chapter number>


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vii

List of Symbols

____________________________________________________________________________

Symbol Description Units

A Current Ampg Acceleration due to gravity - 9.81 m/s

V Voltage Volts

W

T

S

POP

t90CCT

DST

TV

deg

PSM

Weight

Thrust

Reference surface

Density

Power Onset Parameter

Time to roll through 90 deg.

Combat Cycle Time

Dynamic Speed Turn

Thrust Vectoring

Degree

Post Stall Maneuverability

Kg

N

m2

Kg/m3

< Arrange in alphabetical order>


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PART-A

CHAPTER 1

1. Agility1.1.Traditional metrics for performance:

Traditionally combat was dominated by quick sustained turns and the design parameters were

governed by Thrust/Weight (T/W) ratio. This was the traditional means of evaluation performance

which mostly limited to steady state performance even for the fighter planes. But with the

development of modern weapon systems, which requires real-time point-lock-disengage type of

maneuvering, it becomes more important to develop highly unsteady performances, which is

essential in order to remain ahead in a combat situation. One event which brought agility metrics to

the attention of combat analysts was the superior performance of F-86 in Vietnam war against

Soviet MiG-15. On paper with the tradition way of calculating the performance in combat situation

MiG-15 was superior to that of Americans F-15 but actually F-15 proved to be superior in combat

and later it was found that is because of the better agility metrics of the F-15.

Agility is defined as the second time derivative of the steady state variables which are used

for the measure of the performance. Just to be more explicit on the definition.

1.2.Agility metrics classification:

There are mainly two ways of classifying the agility metrics, the first one is based on the measures

of merits used for evaluating maneuvering capabilities and the second way to classify is based on

the timescales of these maneuvers. Firstly maneuvers can be classified into three classes based on

the axis about which these maneuvers are carried out. They are axial: along the velocity vector,

longitudinal: rotation of the velocity vector in the pitching (symmetry) plane and Lateral: rotations

about the velocity vector mainly which is roll.

And based on the timescale of the maneuver we have again three types of agility metrics. They are

Transient: maneuvers analysed are of timescale of 1 to 3 seconds, Functional: Maneuvers that last

for a little longer time typically 10 to 20 seconds and Potential: Largely independent of time and

mainly consists of maneuvers which are not with quick transitions during combat.

Table 1.1 Agility metrics [1]

Table 1.1 shows the classification on the basis of motion axis like longitudinal, lateral and axial

axis and the agility metric which comprises of the transient and functional agility. Some of the

parameters like POP, CCT, t90 etc. used in this agility metric are discussed below.


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Average Pitch Rate:This metrics is used to analyze the pitch agility of an aircraft. It is defined as

the time-averages integral of pitch rate for a given maneuver.

t90: This metric measures the time required for an aircraft to roll through 90 degree starting from

zero initial bank. The input commanded for this maneuvering is a full lateral stick in the directionof the roll. Time required to roll through 90 degree is obtained for different Mach numbers and

angles of attack for different aircrafts in order to compare.

Power Onset Parameter (POP): This metric measures the combined effects of the both the aircraft

thrust and engine spool time, which denotes the time taken by the aircraft engine to bring about the

required change in thrust.

Combat Cycle Time (CCT): It is defined as the time taken to complete the maneuver of 180 deg

heading change and then return to the same Mach number. It evaluates the sum of five time periods

which consists of the individual maneuvers have been tabulated in Table 1.4, along with the inputs

needed to obtain them. It may be noted that CP is the corner point, where the aircraft attains the

maximum instantaneous turn rate.

Table 1.1: CCT Metric []

Figure 1.1: ConceptualCCT Plot []

Thrust vectoring role in improving the agility of a fighter aircraft: Its been evident that TV and

PSM improves the chances of winning in a head to head combat by improving the agility metrics of

the aircraft. From table 1.4 shows CCT metric starts from the point at which aircrafts roll to N zmax.

Therefore the aircrafts turns along Nzmaxand CLmax curves until the pointing margin, to the assumed

stationary adversary aircraft, becomes less than the maximum angle of attack. At this point the

aircraft pitches up to maximum post-stall angle, and points to the adversary for a firing which

marks the end of the maneuver. This metric is used to evaluate the time to complete the maneuver.

The F-18 configs. were tested by them using the above metric: standard configuration with No TV,

AOA for ITR of20deg. And maximum AOA of 30 deg, advanced configuration with TV and AOA

for maximum ITR of 20 deg and maximum AOA of 70 deg. And super-advanced configuration


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with TV and AOA for maximum ITR of 35 deg and maximum AOA of 70 deg. For F-18 the stall

AOA is around 35 deg. The metric was evaluated for a variety of initial Mach number and altitude

combinations together. As expected, the advanced aircraft showed better agility as compared to the

standard configuration because of the added advantage of the post stall maneuvering and activationof TV. The time to complete the maneuver was lesser for the advanced aircraft, especially at higher

initial altitudes, which constitutes a significant advantage. The turn diameter was smaller and the

turn rate was higher as well. Although it was found that the short indicates that PSM provides

significant advantage in combat when it is used for short periods of time. Longer periods of PSM

may lead to greater energy losses, which is detrimental to the performance of the aircraft.

Another demonstration of the advanced capability of TV and PSM was observed when the X-31

was tested against the F-18 in combat scenarios. TV was provided for pitch as well as yaw control

in X-31. X-31 actually has an inferior T/W ratio as compared to the F-18. Further, the maximum

turn rate is lesser than that of the F-18. PSM, however, provided X-31 with a better pointing ability.

The winning maneuver of the X-31 was mostly what is called the Helicopter Attack Maneuver,

wherein the X-31 yawed rapidly in order to point at the adversary which was turning around it. The

yaw control for this maneuver came from the yaw thrust vectoring.

Agility metrics can be used to improve existing designs, by suggesting changes that can be

readily made in the baseline configuration. The baseline configuration can be designed using

some traditional rules such as high T/W, low W/S, etc., and they can be flight tested to get the

necessary data for agility evaluation. Design for agility, among other things, involves efficient

aerodynamics and configuration, adequate control power, and a sound, robust FCS.


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PART-B

CHAPTER 2________________________________________________________________________________

2. Matlab Code2.1Performance Parameters:

This part of the assignment is to develop a matlab code and with that code we need calculate the

performance parameters of XXX. Aircraft and then analyse the difference between the calculated

parameters and the published parameters found from the various public domain published

performance parameters of the aircraft. The code generated is attached to the appendix at the end of

this report.

2.2Power Required:

For steady state of the aircraft the power required should be able to compensate the total drag of the

aircraft, which means power required is equal to total drag in steady state. Power is the product of

thrust and velocity which is given in below.

2.3Power Available for Propeller aircraft:

Thrust available for a propeller driven aircraft is highest at zero velocity called the static thrust and

decreases with an increase in flow velocity (V). The thrust rapidly decreases as V approaches to

speed of sound or sonic speed. This is because the propeller tips encounter compressibility issue

along with the formation of shock waves. It is because of this reason propeller driven aircraft are

limited to low subsonic speeds.

Where is the propeller efficiency and is the shaft power from the piston engine.And we also know that

Where is the thrust available and is the free stream velocity. From the above equation thrustavailable can be calculated.

2.4Power Available for Jet aircraft:

For subsonic speeds of an aircraft the thrust available of a jet engine propelled aircraft is nearly

remains constant with the speed of free stream air

2.5Maximum Velocity:

The maximum velocity of an aircraft is calculated by equation (3) and for steady level flight

and for flight at Vmax, the thrust available is at its maximum value. i.e max


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---------Eq. (3)

From equation 3 we can conclude the following:-

Vmax increase as max / W increases. Vmax increase as W/ S increases.

Vmax decreases as CD0and/or K increases.


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2.6Stall Velocity:

At a given altitude the velocity at which an aircraft stalls is determined by both C Lmaxand the wing

loading. For steady level flight

-------------------------Eq.(4)Hence,

--------------------------

Eq(5)

When the max is inserted in equation(5) the corresponding value of is the stalling velocity.

--------------------------Eq(6)

Table 2.1 CLmax /cos(lambda)

max achieved by high-Lift devices on finite wings and also can be calculated by using table 2.1,

if , sweep back angle of the quarter-chord line, is known.

2.7Range of Jet engine aircraft:

2.8Range of Propeller driven engine aircraft:

2.9Endurance of Jet engine aircraft:

2.10 Endurance of Propeller driven engine aircraft:

2.11 Rate of climb:

Rate of climb (R/C) depends on the raw power in combination of the weight of the aircraft. The

higher the thrust, lower the drag and the lower the weight, the better climb performance.

= --------------------------Eq(6)Figure 2.1 gives the excess power available for the propeller driven aircraft and the jet propelled

airacraft by using the graphical approach. And figure 2.2 gives the graphic way to interpret the

values for Vmaxand (R/C)max.


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Figure 2.1 Excess Power []

Figure 2.2 Variation of rate of climb with velocity at a given altitude []

2.12 Glide performance:

When power required is more than the available for a flying aircraft or in case of engine failure

instead of climbing the aircraft start descending an aircraft will be gliding. The equilibrium glide

velocity value depends on the altitude and wing loading.

--------------------------Eq(6)

2.13 Takeoff field length:

2.14 Landing field length:

2.15 Turning rate:

2.16 Turn radius:

2.17 Longitudinal static stability:


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PART-C

CHAPTER 3________________________________________________________________________________

3. Performance Comparison Range of Jet engine aircraft:

Simulation may be addressed as prudence for ones views and action, which can help in better

handling of a given situation in real time with less trouble and preparedness. The need for

simulation of any given action of mankind to meet the challenges of the century is growing at a

considerable rate. Some of the major areas of simulation intervention for better planning and

execution of the projects are:


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Military operation

Natural resource harvesting (Dam construction, Mining, Nuclear plant erection)

Manufacturing

Health services

Transportation

Space exploration

Telecommunication

Service operations (Banks, Hotels etc)

Emergency / natural disaster planning etc.

Simulation can be as simple as a mathematical model or complex computer software. Most of the

operational models are dynamic, discrete-change and stochastic, which invariably need a computing

facility to see the result within a given time. One of the main drawbacks of any simulation is one

cannot obtain exact answer but can obtain only approximate answer.

3.2Range of Jet engine aircraft:

3.3Endurance of Jet engine aircraft:

3.4Rate of climb:

3.5Glide performance:

3.6Takeoff field length:3.7Landing field length:

3.8Turning rate:

3.9Turn radius:

3.10 Effect of varying W/S and T/W on turn and take off performance:

3.11 Longitudinal static stability from wing and tail:

Table 3.1 ,POIJ

Table 3.1 jfhdliufgdfdiugfpfid


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Figure 3.1 ffjghfdiguhfdiugh


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References

________________________________________________________________________________

1. Robert N. Lussier. (2008) Management Fundamentals, 4thEdition, Southwestern CollegePublishing, Thomson Learning.

2. Stephen Robbins and Mary Coulter. (2004)Management, 8thEdition, Prentice Hall.3. Gareth R. Jones and Jennifer M. George. (2007) Contemporary Management,

5thEdition, McGraw-Hill.

4. Robbin Stephen and DeCenzo David. (1995)Fundamentals of Management, Prentice HallPublishers.

5. Kinicki and Williams Irwin. (2008)Management, McGraw Hill.6. Decenzo David and Robbin Stephen A. (1996)Personnel and Human Reasons

Management, Prentice Hall of India.

7. J.A.F. Stoner, Freeman R. E and Daniel R Gilbert. (2004)Management, 6th Edition, PearsonEducation.

8. Fraidoon Mazda. (2000)Engineering Management, Addison Wesley.


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Guideli nes for wr iting the report

1. Inserting a table

Table 1.1 Properties of Air at Low Pressure [Ref.]

T (K) h (J/kg) p (atm) u (J/kg) (J/kg K)

[Note: the table should be centered w.r.t the page width. Use suitable units]

Referring to a table in the text:

The data is tabulated as shown in Table 1.1.

[Note: Please do not write as As shown belowor As shown above]

2. Inserting a figure, a photo or screen shot

Figure 2.1 Machining Process [Ref.]

Referring to a figure in the text:

The machine is shown in Figure 7.1

[Note: Please do not write as As shown belowor As shown above]

Figure

Title of the table should be at the top of the table and be left justified with ref to table

Title of the Figure should be at the bottom

of the figure and be left justified. The

reference must be quoted.

The figure should be sufficiently large and

legible. It should be centered w.r.t the page


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Figure 7.1 The Wonder Machine [2]

3. Quoting the references in the text

According to Kestin[5], the science of thermodynamics is a branch of physics. It describes

natural processes in which changes in temperature play an important part. Such as the

..

4. A chapter should always start on a new, right side page.5. The Bibliography section should be after the References.6. The Appendix if any should be the last section in the report.

[5].. reference number;

this should be quoted in the

References.

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