design,analysis and fabrication of wing-in-ground effect vehcile

DESIGN OPTIMIZATION AND FABRICATION

OF A WING IN GROUND EFFECT CRAFT

(Sponsored by CERD, Govt. of Kerala)

A project report submitted in partial fulfillment of the requirements for the

award of the degree of Bachelor of Technology in Mechanical Engineering of

Mahatma Gandhi University

SUBMITTED BY

ANIL T.

ARAVIND R.

NIKHIL S. PILLAI

RAHUL VINOD

SUDHEESH KUMAR E.

ZAHIR UMMER ZAID

Under the Guidance of

Mr Antony J.K.

DEPARTMENT OF MECHANICAL ENGINEERING

2010-2014

RAJIV GANDHI INSTITUTE OF TECHNOLOGY

(GOVERNMENT ENGINEERING COLLEGE, KOTTAYAM)

DEPARTMENT OF MECHANICAL ENGINEERING

RAJIV GANDHI INSTITUTE OF TECHNOLOGY

GOVERNMENT ENGINEERING COLLEGE

KOTTAYAM– 686 501

Certificate

This is to certify that the report entitled “DESIGN OPTIMIZATION, FABRICATION AND

FEASIBILITY STUDY OF A WING IN GROUND EFFECT CRAFT” is a bonafide record of Graduate Project

presented by ANIL T (Reg. No. 10013661), ARAVIND R (Reg. No. 10013664), NIKHIL S PILLAI (Reg No.

10013689), RAHUL VINOD (Reg. No. 10013692), SUDHEESH KUMAR E (Reg No. 10013707), ZAHIR

UMMER ZAID (Reg No. 10013716) during the year 2013-2014. This report is submitted 1to Mahatma

Gandhi University, Kottayam in partial fulfilment of the requirements for the award of the degree of

Bachelor of Technology in Mechanical Engineering.

ANTONY J.K. CIBY THOMAS

Assistant Professor Professor and HOD

Dept. of Mechanical Engineering Dept. of Mechanical Engineering

RIT, Kottayam RIT, Kottayam

(Project Guide)

DESIGN OPTIMIZATION, FABRICATION AND FEASIBILITY STUDY OF A WING IN GROUND EFFECT CRAFT

RIT, KOTTAYAM i DEPT. OF MECHANICAL ENGINEERING,’10–‘14

ACKNOWLEDGEMENT

On the occasion of presenting the project report, we wish to express our deep and

profound feeling of gratitude towards a number of persons who have contributed to the

successful completion of our project.

First of all, we express our deep gratitude to Lord Almighty, the supreme guide, for

bestowing his blessings through each phase of our work.

We would like to thank Antony J.K. (Assistant Professor, Department of Mechanical

Engineering, RIT, Kottayam) for his consistent guidance and inspiration throughout our

project work. We would like to thank Manoj KumarM (Assistant Professor, Department of

Mechanical Engineering, RIT, Kottayam), Mr Graham Taylor (MBA, MCMI,

MIET Hypercraft Associates Ltd, 23 Wyndham Avenue, High Wycombe, Bucks HP13 5ER,

England), Shivprasad (HOD, Ship Technology Dept., CUSAT) and Mr Dileep (Professor,

Ship Technology, CUSAT) for their guidance and support.

We also express our heartfelt gratitude to Ciby Thomas (H.O.D Department of Mechanical

Engineering, RIT Kottayam) and Dr. K. P. Indiradevi (Principal, RIT Kottayam) for

rendering all possible help and support during our project.

Last but not the least we are grateful to the management, all the staff members of RIT

Kottayam for their cooperation and help extended during the course of our project. We would

also like to thank all our friends, family members for their encouragement, inspiration and

moral support without which this work would have never been possible.

Anil T

Aravind R

Nikhil S Pillai

Rahul Vinod

Sudheesh Kumar E

Zahir Ummer Zaid


RIT, KOTTAYAM ii DEPT. OF MECHANICAL ENGINEERING,’10–‘14

ABSTRACT

This project mainly encompasses through the design, analysis and fabrication of a

wing-in-ground effect craft. Starting with an introduction to the technology, the project

covers topics such as the design parameters of the hull, main wing, horizontal and vertical

stabilizers and the end plates along with the analysis reports for the same. Covered in more

detail are the fabrication techniques involved in the construction of the same. A brief

feasibility study of the technology considering the Chennai-Port Blair maritime route is

conducted. The project concludes with the challenges and the problems this new technology

might encounter as a new transport replacement in the market.

The WIG craft specified in this report corresponds to the International Maritime

Organization classification type A, and consequently, is designed to operate only within

ground effect. As a result, this type of aircraft is not confined by strict aviation standards, as

well as an increase in safety and usability.


RIT, KOTTAYAM iii DEPT. OF MECHANICAL ENGINEERING,’10–‘14

CONTENTS

TITLE PAGE NO.

1. INTRODUCTION 1

2. INITIAL DESIGN 4

3. HULL DESIGN 6

4. WING DESIGN 12

5. HORIZONTAL STABILIZER 26

6. VERTICAL STABILIZER 29

7. END PLATE 30

8. FABRICATION 31

9. ENGINE AND RELATED COMPONENTS 35

10. ELECTRIC AND ELECTRONIC UNIT 39

11. SCOPE OF WIG CRAFT 40

12. COST REPORT 45

13. ADVANTAGES AND OPPORTUNITIES 47

14. CHALLENGES AND LIMITATIONS 48

15. CONCLUSION 50

16. REFERENCE 52


RIT, KOTTAYAM iv DEPT. OF MECHANICAL ENGINEERING,’10–‘14

LIST OF FIGURES

FIGURE NO. DESCRIPTION PAGE NO.

FIGURE 1 EFFECT OF CL VALUE OF AIRCRAFT 2

FIGURE 2 VORTEX STRENGTH 3

FIGURE 3 PLAN PROVIDED BY GRAHAM TAYLOR 4

FIGURE 4 CATIA MODEL OF THE PLAN 5

FIGURE 5 PLAN OF HULL 7

FIGURE 6 HULL STRUCTURE 9

FIGURE 7 DROP TEST ON HULL 10

FIGURE 8 HULL MODAL ANALYSIS 11

FIGURE 9 AIRFOILS OPERATING IN STRONG GE AT LOW AOA 13

FIGURE 10 CL VS AOA 15

FIGURE 11 CD VS AOA 16

FIGURE 12 VELOCITY CONTOUR AT 130

AOA 16

FIGURE 13 AERODYNAMIC EFFICIENCY VS AOA 17

FIGURE 14 OPTIMUM AIRFOIL CONFIGURATIONS 19

FIGURE 15 STRUCTURE 20

FIGURE 16 EQUIVALENT ELASTIC STRAIN 21

FIGURE 17 EQUIVALENT ELASTIC STRESS 22

FIGURE 18 TOTAL DEFORMATION OF WING 23

FIGURE 19 MODAL ANALYSIS 24

FIGURE 20 WIG DESIGN 27

FIGURE 21 COUNTOUR OF STATIC PRESSURE OVER NACA0006 27

FIGURE 22 PRESSURE COEFFICIENT OVER NACA 0006 27

FIGURE 23 COUNTOUR OF STATIC PRESSURE OVER NACA16006 28

FIGURE 24 PRESSURE COEFFICIENT OVER NACA 16006 28

FIGURE 25 FINAL WIG DESIGN 31

FIGURE 26 FINAL DESIGN 38


RIT, KOTTAYAM 1 DEPT. OF MECHANICAL ENGINEERING,’10–‘14

Chapter 1

INTRODUCTION

Ground Effect is a phenomenon when a lift generating device, like a wing, moves

very close to the ground surface which increases the lift-to-drag ratio. Pilots of huge airplane

often experience the plane „bounces‟ off the runway in the presence of ground effect just

before touch down. This phenomenon that resulted in the aerodynamic efficiency of the

vehicles was first exploited by the Russians whom designed and build the first WIG craft

during the cold war.

1.1 Theory of Ground Effect Aerodynamics

When a wing approaches the ground, an increase in lift as well as a reduction in drag

is observed which results in an overall increase in the lift-to-drag ratio. The cause of the

increase in lift is normally referred to as chord dominated ground effect (CDGE) or the ram

effect. Meanwhile, the span dominated ground effect (SDGE) is responsible for the reduction

in drag. The combination of both CDGE and SDGE will lead to an increase in the L/D ratio

hence efficiency increases.

1.2 Chord Dominated Ground Effect (CDGE)

In the study of CDGE, one of the main parameters which one considers is the height-

to chord (h/c) ratio, h. The term height here refers to the clearance between the ground

surface and the airfoil or the wing. The increased in lift is mainly because the increased static



pressure creates an air cushion when the height decreases. This result in a ramming effect

whereby the static pressure on the bottom surface of the wing is increased, leading to higher

lift. Fig shows the difference between an airfoil without ground effect and with ground effect.

Theoretically, as the height approaches 0, the air will become stagnant hence resulting in the

highest possible static pressure with a unity value of coefficient of pressure.

Fig 1: Effect on the value of CL when an airfoil is in ground effect and outside ground

effect. LEFT: With ground effect CL=0.71. RIGHT: Without ground effect CL=0.558

1.3 Span Dominated Ground Effect (SDGE)

On the other hand, the study of SDGE consists of another parameter known as the

height to- span (h/b) ratio. The total drag force is the sum of two contributions” profile drag

and induced drag. The profile drag is due to the skin friction and flow separation. Secondly,

the induced drag occurs in finite wings when there is a „leakage‟ at the wing tip which creates

the vortices that decreases the efficiency of the wing. In SDGE, the induced drag actually

decreases as the strength of the vortex is now bounded by the ground. As the strength of the



vortex decreases, the wing now seems to have a higher effective aspect ratio as compared to

its geometric aspect ratio resulting in a reduction in induced drag.

Fig 2: Vortex strength of aircraft in flight 1) In ground effect 2) Without ground effect



Chapter 2

INITIAL DESIGN

It was very difficult to start the design of a craft right from the start. In the search for a

basic design structure, after many days of rigorous search, we came across a website called

the www.grahamktaylor.com.

We contacted Mr Graham K. Taylor (MBA, MCMI, MIET Hypercraft Associates

Ltd, 23 Wyndham Avenue, High Wycombe, Bucks HP13 5ER, England) who was

overwhelmed by the project and offered to send the basic plan packs which usually came

with a small fee, free of cost.

Fig 3: Plan provided by Mr Graham Taylor



Fig 4: CATIA model of the plan

The basic design came by airmail in the first week of January in an A1 sheet with a

full scale drawing and was the initial design for the project.

On close research, we found that though the hull structure was structurally strong it

couldn‟t minimize hydrodynamic resistance to a great extent.

Moreover the wing was flat which means it wasn‟t an aerodynamically viable one and

had to be replaced.

So it was decided to drop the canard configurations, elevators, replace the balsa wood

with proper substitutes, increase the aspect ratio to 2 from 1 and replace the electric motor

propulsion with engines.

The basic things we incorporated from the basic design into our final design were:

Propulsive unit positioning

Basic dimensions

End plate shapes

Augmented lift production by tilting the engines



Chapter 3

HULL DESIGN

One of the important design aspects in the project was that of hull. Since the craft is in

close proximity to water during flight and takes off and lands in water bodies, it was really

important to have a good solid hull design that would keep the craft afloat when in water. The

transitory phases of operation from rest through boating, planing or hovering through hump

speed and accelerating through take-off into ground effect flight all require minimum

hydrodynamic resistance so as to minimise installed power.

For a proper hull design, it was necessary to take the aid of experts in the field and

help was sought from the department of Ship Technology of Cochin University of Science

and Technology.

The head of the department Mr. Sivaprasad and Mr Dileep Kumar (Professor, Ship

Technology) gladly extended their support.

The design of the hull commenced with the computations to find the maximum

loading capacity of the craft. It was fixed to be around 8 kgs as per the instruction of the

professors, Hull Model No. TMB-4667 (Hard-chine boat, Lp/bpx=4.09) was selected (as the

hull shape was simpler and would easily suit to the demands of overcoming hump speed

faster) from the “Small craft Data sheets” by “Society of Naval Architects and Marine

Engineers, New York”.



Fig 5: Plan of hull

The hull design is a planing hull, with a low drag profile compared to others

researched. A planing hull operates by pushing water downwards and sideways as the hull

moves over the water surface, thus, creating a hydrodynamic lift force.

From the reference hull given, (whose length is around 8 feet), the block coefficient

was found to be around 0.587 from the body plan and the outboard profile.

Cb= / Lw Bw T

Where = Volume of Displacement at rest

Then the model of size 8 feet had to be dimensionally brought down to something that would

be around 1m for the model.

New Station Spacing = Model Station Spacing x L2/L1

Where L2= new length

L1= model length

The weight carrying capacity for a craft of 1m length and corresponding dimensions

were computed and was found to be around 5 kg which was way short of the required weight.



W=CbLwlBwlT

Where

W = Total weight of the body it can sustain

Cb = Block coefficient

Lwl = Length at waterline

Bwl = Breadth at waterline

T = Draft

= Density of water

In order to accommodate a weight of around 8 kg, the length was now proportionally

increased.

L23=L1

3*required weight/ obtained weight for a length of 1 m

Where L2 = new length

L1 = Initial computation length (1 m)

After certain iteration of the same sort, the following dimensions were fixed for the hull.



HULL Parameters

Craft : Tentative Parent for Planning Series

Type of Section Shape : Convex (Forward), Straight (Aft)

Maximum Length : ` 1.19 m

Maximum Breadth : 0.29 m

Breadth at Waterline : 0.24 m

Draft : 0.05 m

Projected Planning Bottom Area : 0.2816 m2

Weight Carrying Capacity : 8.4 kg

Fig 6: Hull structure



Fig 7: Drop test of hull. (From top) 1) Equivalent Strain 2) Equivalent Stress 3) Total

Deformation



Fig 8: Hull modal analysis

The fundamental mode of is 77.585 Hz, the hull would be safe until the exciting

frequency matches with this point or matches with the frequency of higher modes of

vibration. If the exciting frequency matches with this point resonance would take place,

leading to high amplitude of oscillations and damaging of the hull.

From the analysis it was confirmed that the hull has enough strength to endure the forces

generated during a sudden impact with the water surface.



Chapter 4

WING DESIGN

The objective of the wing design is to provide sufficient lift to the aerodynamic body,

also the wing should have a streamlined shape to reduce the drag force and the configuration

should be such that it provides maximum aerodynamic efficiency.

The wing design started with choosing the wing profile. For an aircraft flying in the

ground effect region the shape of lower side of the airfoil is very important. In many cases

designers opt for a flat lower side because a convex lower side may in certain situations lead

to suction at the lower side, either hydrodynamic or aerodynamic. A concave bottomed wing

section leads to very poor longitudinal stability. Based on the data collected, DHMTU airfoil

was found to provide maximum efficiency in the ground effect region as it is having a flat

lower portion and an S shaped camber line which is favourable for stability. To verify this

CFD analysis of the DHMTU profile was done and this was compared with the CFD analysis

of other NACA profiles which were commonly used. DHMTU 8-40-2-10-3-60-20-15 was

chosen as it has an appropriate nose radius which would lag the flow separation in strong

ground effect region. It was also found out that this airfoil has maximum aerodynamic

efficiency at 6 degree of angle of attack.



Fig 9: Airfoils operating in strong ground effect region at low AOA. LEFT: suction

effect is very high on a NACA 0015 profile, CL=-1.2. RIGHT: suction effect is very small

on a DHMTU, CL=-0.1.

Characteristics of DHMTU airfoil

It was found that the drag of the DHMTU decreases with decreasing altitude.

The DHMTU possesses superior L/D at low angles of attack when in ground effect.

Lift of a section increases as the proximity to the ground decreases.

The airfoil geometry was obtained from UIUC Applied Aerodynamics Group‟s website.

DAT files of various airfoils shape are available for free in their website, as DAT file is not

compatible for CATIA the designers used PROFSCAN software to generate a DXF file

which is compatible in CATIA. The CFD analysis was performed in ANSYS software.



4.1. CFD analysis for different airfoils at 6 degree angle of attack in ground effect

region (h/c=20%) at 30m/s

Comparison of DHMTU airfoil with other airfoils [5] used for ground effect vehicles

shows that, DHMTU has the maximum lift coefficient in the ground effect region and hence

it provides maximum lift to the vehicle.

AIRFOIL CL

DHMTU 0.778

GLENN MARTIN 2 0.734

CLARK Y 0.736

NACA 2412 0.73

NACA 16006 0.715

TABLE 1: CL values of different airfoils at 6 degree angle of attack in ground effect

region (h/c=20%) at 30m/s.

4.2. CFD analysis of DHMTU airfoil at different angle of attacks at 30m/s

Table 3 provides indication that as the AOA increases the value of CL increases up to

a certain point and later it decreases. The maximum value of CL is at 130 AOA and its value

is 0.9. It can be seen that the maximum value of aerodynamic efficiency is at 60 AOA and its

value is 13. The aerodynamic efficiency is high at low values of AOA.



AOA L/D

3 0.25 0.023 10.86

4 0.49 0.04 12.25

5 0.51 0.04 12.75

6 0.52 0.04 13

7 0.72 0.07 10.28

8 0.77 0.09 8.55

9 0.88 0.109 8.07

12 0.89 0.17 5.2

13 0.9 0.175 5.1

14 0.86 0.2 4.3

TABLE 2: Table of aerodynamic efficiency of DHMTU airfoil at different angle of attacks.

Fig 10: Cd vs A.O.A

It can thus be inferred that increase in the angle of attack increases the coefficient of drag as

well.

0

0.05

0.1

0.15

0.2

0.25

3 4 5 6 7 8 9 12 13 14

Cd

Angle of Attack

Cd vs A.O.A



Fig 11: Cl vs A.O.A

From the above graph, it can be inferred that Cl increases with an increase in the angle of

attack till 13o after which stalling occurs and the value of Cl starts decreasing.

Fig 12: Velocity Contour at 130

AOA

0

0.2

0.4

0.6

0.8

1

3 4 5 6 7 8 9 12 13 14

Cl

ANGLE OF ATTACK

Cl vs A.O.A



Fig 13: Aerodynamic efficiency VS AOA

From the above analysis it is clear that the maximum value of aerodynamic efficiency

is at 6 degree angle of attack. Therefore 6 degree angle of attack was chosen.

After fixing the wing profile and the angle of attack, the next thing that was calculated

was the surface area of the wing. Before that the shape of the wing was taken as rectangular

for the ease of fabrication.

L= ⁄

Lift force is equal to the weight of the WIG aircraft which is equal to 10*9.81=98.1N

The value of at sea level is 1.225kg/

V is the true air velocity which is 30m/s

is the coefficient of lift which depends on the airfoil shape and its angle of attack.

Considering the wing tip vortices effect was taken as 0.5.

S is the area of the wing surface which was calculated to be 0.363 sq meters.

0

2

4

6

8

10

12

14

3 4 5 6 7 8 9 12 13 14

L/D

RA

TIO

ANGLE OF ATTACK

L/D RATIO vs AOA



For a WIG aircraft the effective span increases due to incomplete vortices formation

as discussed earlier. So considering the geometric constraints, the aspect ratio was fixed as 2.

The small aspect ratio of the WIG aircraft provides maximization of efficiency of power

augmented take-off.

Aspect ratio=

=

So Chord=0.429m and Span=0.853m

4.3. CFD analysis for DHMTU airfoils at various heights above the sea level in ground

effect region at 6 degree angle of attack at 30m/s

It can be inferred from Table 4 that as the proximity to the ground increases the value of CL

and hence lift force increases.

h/c %

20 0.778

30 0.76

40 0.594

50 0.584

60 0.568

100 0.5

TABLE 5: Variation of with height in ground effect region



4.4 CFD analysis for DHMTU airfoil at various velocities.

It is indicated from the table that as the value of free stream velocity increase the

value of lift increases and that of drag reduces as the result the value of aerodynamic

efficiency increases.

VELOCITY(m/s) CL CD CL/CD

30 0.7617 0.0753 10.11

40 0.765 0.0745 10.26

50 0.767 0.0741 10.35

60 0.7685 0.0739 10.39

70 0.769 0.0736 10.47

80 0.7715 0.0734 10.51

90 0.7734 0.0735 10.52

100 0.7735 0.0733 10.55

120 0.776 0.0732 10.60

140 0.777 0.0728 10.67

TABLE 4: Variation of CL/CD with velocity in ground effect region

Fig 14: OPTIMUM AIRFOIL CONFIGURATION: CFD analysis of DHMTU airfoil at

60 AOA, V=30m/s, h/c=20%



4.5 WING STRUCTURE DESIGN

The objective of structure design was to provide sufficient strength to the wing so that

it doesn‟t buckle and flutter due to the forces acting on it. Three wing structures were chosen

and designed; model analysis and structural analysis were performed on all the three wings

and the optimum wing was chosen.

WING 1 WING 2 WING 3

WEIGHT 0.632 kg 0.613 kg 0.604 kg

NUMBER OF

SPARS

NPS 1/8 SCH 5 SDS NPS 1/8 SCH 5 SDS NPS 1/8 SCH 5 SDS

NUMBER OF RIBS 3 of 0.02 inch 2 of 0.02 inch 2 of 0.02 inch

TABLE 5: Different wing configuration.

1) 2)

3)

Fig 15: Structure 1) WING 1, 2) WING 2, 3) WING 3



1) 2)

3)

Fig 16: Equivalent Elastic Strain 1) WING 1, 2) WING 2, 3) WING 3



1) 2)

3)

Fig 17: Equivalent stress 1) WING 1, 2) WING 2, 3) WING 3



1) 2)

3)

Fig 18: Total deformation 1) WING 1, 2) WING 2, 3) WING 3



1) 2)

3)

Fig 19: Modal analysis 1) WING 1, 2) WING 2, 3) WING 3

It was determined from the above analysis that for efficient and strong designs the

spacing or ribs should lie around 50% of chord length as in design wing 1.

As weight of all three wings were approximately the same, wing 1 was easy to

fabricate and didn‟t flutter much even if its resonance frequency matches with the exciting

frequency. So wing 1 was chosen as the optimum wing.

Frequency of fundamental mode for wing 1 = 51.363 Hz



In an aircraft the exciting frequency is due to vortex shredding, which occurs in a

oscillating flows that takes place when a fluid such as air or water flows past a surface at

certain velocities, depending on size and shape of the body. In this flow, vortices are created

at the back of the body and detach periodically from either side of the body. The fluid flow

past the object creates alternating low pressure vortices on the downstream side of the object.

The object will tend to move towards the lower pressure zone. If this frequency matches with

the resonant frequency, large amplitude vibrations takes place leading to damaging of the

parts.

St = fL/V

St is the Strouhal number = 0.198(1-1/Re)

Re is the Reynolds number = =8.89*

is the = 1.798* Ns/

L is the chord length = 0.429m

V is the flow velocity = 30m/s

f=vortex shedding frequency which was calculated to be, = 14Hz

As the value of exciting frequency is very much far away from the fundamental frequency of

the wing so the wing would not go into resonance and hence it would be safe and no

fluttering would occur.



Chapter 5

HORIZONTAL STABILIZER

The main objective of designing the horizontal stabilizer is to trim the aircraft.

The centre of pressure of the main wing is at 0.33h/c as it is in the ground effect

region and that of the horizontal stabilizer is taken at the quarter chord point as it is outside

the ground effect region.

The centre of gravity of the WIG aircraft is 0.15m in front of the centre of pressure of the

main wing.

Main wing

Chord length = 0.429m

Span = 0.853m

Aspect ratio = 2

Horizontal stabilizer

Chord length = 0.255m

Span = 0.355m

Aspect ratio = 1.7



Fig 20: WIG Design

The centre of pressure of the horizontal stabilizer is at a distance 5*(distance of centre

of pressure of front wing from the centre of gravity). The lift force acting on the horizontal

stabilizer is 20N.

For horizontal stabilizer, for ease of fabrication symmetric airfoil profile is chosen. To

choose an optimum profile CFD analysis was done on some airfoils.

NACA0006

Fig 21: Contours of static pressure Fig 22: Pressure coefficient over a NACA0006



NACA16006

Fig 23: Contours of static pressure Fig 24: Pressure coefficient over a NACA16006

From the above analysis it is clear that in NACA16006 flow separation is delayed due

to delay in the adverse pressure gradient, hence NACA 16006 would have lower drag

compared to NACA 0006. Angle of attack was fixed as -6 degree, as aerodynamic efficiency

is maximum at this angle. for NACA 16006 at 6 degree angle of attack was found to be

0.5, considering the end effects for calculation it was taken as 0.4.

From L= ⁄

True air velocity was found to be 30m/s. The surface area was calculated to be 0.0907 sq.

meter.



Chapter 6

VERTICAL STABILIZER

The main objective to design a vertical stabilizer is to provide direction stability. For

the ease of fabrication the same airfoil was chosen i.e. NACA16006.The vertical stabilizer

was designed to have approximately half the area as that of the horizontal stabilizer. Height

of the vertical stabilizer was fixed as 0.192m. This value was taken considering the diameter

of propeller being mounted upon the horizontal stabilizer. The vertical stabilizer was made bit

curved from the front side to increase the supporting area for the engine mountings to be kept

over the horizontal stabilizer. The mean chord of the wig is 0.2725m.

6.1 Rudder and Elevator

The main objective of designing a rudder is to allow the pilot to control the yaw

motion of an aircraft. The rudder should have sufficient area to help the pilot to control the

yaw motion.

The elevator is designed to control the pitch of the WIG craft.

The rudder and elevator hinge line is positioned at 73% of vertical and horizontal stabilizer

chord respectively.



Chapter 7

ENDPLATES

The main purpose of endplates in WIG aircraft is to increase the ram effect. The ram

effect is due to the growth of the pressure difference below and above the vehicle, the

endplates become an effective means to hinder the leakage of the air from under the wing.

Characteristics of endplates

Use of endplates leads to noticeable augmentation of the effective aspect ratio.

The smaller the aspect ratio the more efficient are endplates.

The highest increase of the lift coefficient due to the endplate occurred when the

centre of the endplate coincided with the centre of the wing.

The endplate should be so designed that its bottom surface should be just touching the

water level.



Chapter 8

FABRICATION

Fig 25: Final wing design

8.1 Hull

The parameters of the hull have been as given in the previous section on hull design.

Fabrication of a hull is an intricate process and hence needs to be done in good

precision limits. As a result, it was initially proposed to fabricate the hull using fibre glass. As

a part of moving on, help was sought from Praga industries, Aroor who initially consented

and assured the fabrication with the same.



On further analysis, the project team and the industry decided to drop the idea of

complete fabrication in fibre glass due to the high cost incurred and the difficulty in making a

pattern and finally a die for a single piece of experiment which seemed impractical.

It was later decided to fabricate using plywood, as suggested by the MD of the

industry, who also promised to give us a coating of fibre glass to the model if the need arises.

But the complex shape of the hull and the related 3D curves made it a difficult task

for us to pursue the fabrication with plywood.

Finally, it was decided to continue with wood and the probable materials were

shortlisted. Keeping in mind the requirements of light weight, low cost, easy availability and

easy machinability the wood were shortlisted to mahogany.

Advantages of Mahogany wood

It is straight grained and free of voids and pockets

It has excellent workability and durability

It resist wood rot

Attractive appearance

Can be glued easily and can be finished and polished

The item was purchased with the help of a local carpenter who has would assist in the

machining of the wood into the required shape. Two lumps of wood of 5 inch by 5 inch by 5

feet were purchased.

As per the plan, the entire hull design had to be divided into 14 different planes

incorporating side and top view with cross sectional view in each plane for fabrication. These

different views should collectively give the entire structure of the hull.



8.2: Wing

SL

NO

MATERIAL SPECIFICATIONS QUANTITY

1 Aluminium sheet 0.508 mm*500mm 2 m

2 Aluminium sheet 0.508 mm*500mm 0.4 m

3 Aluminium pipe Outer

radius:5.144mm

Inner radius:4.255mm

3 m

4 Wood-Mahogany

Table 6: Material requirement

Advantages of Aluminium over other materials:

Low Density of 2.7g/m^3

Relative high strength properties

Good thermal and electric property

High corrosion resistance

Technological effectiveness



It is decided to fabricate the wing using Aluminium sheet of thickness 0.508 mm. The

joining is done by riveting. The strengthening structure will also be constructed in

aluminium. The ribs will be made by cutting airfoil shape in aluminium sheet of 0.508 mm

thickness. The holes are drilled for connecting spars. There will be two spars connecting the

ribs. The spars are made up of aluminium pipes of outer radius 5.144 mm and inner radius

4.255 mm. The free space between the ribs and spars are filled with thermo coal. The wing is

attached to the hull by screwing the spars at the platform at the centre of hull. The end plates

are made up of wood (Mahogany) and screwed to the outer rib.



Chapter 9

ENGINES AND RELATED COMPONENTS

The power-plant for the craft was selected on the basis of the thrust produced by it when

coupled to the propeller of specified pitch and diameter. The nitro-fuel model IC engines

were preferred over the electric motors for the following reasons:

comparatively higher power-output (available power ratings of the electric motors

were insufficient )

operating cost (market survey confirmed that even though the motor cost was lower,

the battery was expensive)

weight ( mechanical leverage over the heavy batteries )

To select the IC engine and a suited propeller, it was required to fix the thrust essential

for the craft. As the estimated dead weight of the craft was about 8 kg, it was decided to have

a thrust of 8kg to overcome the different types of drag that the craft experiences which

includes hydrodynamic drag, the planning mode-GEZ transition drag and the aerodynamic

drag, thus assuring a completely effective propulsive unit. The combined thrust of the three

IC engines should overcome all of the above cited drag, so each engine-propeller

combination should at least possess a thrust of 2.66 Kg. For deciding on the IC engine it was

required to decide on the manufacturer based on the criteria of cost, weight and simplicity of

the design and operation. Many RC flying-clubs were contacted for getting acquainted with

the various engine manufacturers and it was decided to contact the Super-Tigre company,

based in Illinois, US. The different categories of engines were again compared and the 2-



stroke engines were selected for their superior power-to-weight ratio and operational

simplicity over the 4-stroke engines. There were a total of 10 engines available from the

company for aero-applications. Three engines, namely GS 40, GS 45 and GS 75,were

selected for comparison and performance study based on its application. The possible power-

plant configurations were as cited below:

Two GS 40 engines as bow-thrusters and one GS 75 engine as the main propulsive

unit.

Two GS 45 engines as bow-thrusters and one GS 45 engine as the main propulsive

unit.

The power-plant configuration was selected by the determining the static thrust parameter for

various engine-propeller combinations. The static thrust (the thrust produced at zero air-

speed) was initially decided to be determined using the following equation:

However as the multitude of the inputs required were not available and the calculation

which related the thrust with the power output of the engines rendered additional complexity

to the procedure, it was decided to devise an alternative method. Different soft wares were

available for calculating the thrust from a particular engine-propeller combination; a well-

regarded software, the Static Thrust Calculator was used to determine the thrust for all the

engine-propeller combinations specified by the manufacturer.



The STC software required the following inputs:

Propeller diameter and pitch

Propeller type (Manufacturer-dependent)

No. of blades

Operating RPM

Air temperature and density

The calculation yielded the thrust produced from the combination and the horse-power

required producing that much of thrust, so for each engine-propeller combination it was

required to counter-check whether the calculated „required horsepower‟ was within the rated

horsepower of the engine.

This required-horsepower parameter helped in confining the propeller selection criterion

to a small range of propellers for each engine. For example, the GS 75 engine produced 3.22

kg of thrust @ 2.2 hp when a 10X8 propeller was used and produced 3.5 kg thrust @ 2.4 HP

when a 11X8 propeller was used.

By calculating and comparing the thrust and required horsepower parameter the second

power-plant configuration was confirmed given our geometric constraints and thrust

parameters and expenditure. The GS 45 engine was rated 1.5 HP @ 16000 rpm and the

propeller was a 10X6 APC W standard, the engine-propeller combination yielded 3.33kg

thrust @ 1.48 HP with an estimated flying speed of 90kph.

The RFQ was placed for the engines and accessories and the company acquainted an

affordable package, consolidating the total cost at INR 15,800/- .



Fig 26: Final design



Chapter 10

ELECTRICAL AND ELECTRONIC UNITS

This aircraft is a scale down model and the control is carried out through a radio

control unit. There are total five servomotors in this system for controlling the throttle

openings of three engines, rudder and to actuate the front engine platform tilting mechanism.

The five channel radio control unit of 300 meter range (Including transmitter, receiver) for

controlling these servomotors is purchased as a readymade unit and the servomotors with

control unit of required specifications are also purchased. A 6V rechargeable DC battery is

used to power these motors, control system and receiver. The servomotors are linked with

rudder and carburettor through simple linkages and the servomotor controlling the engine

angle is connected to engine platform through a reduction gear mechanism. The system is

tuned according to convenience of the operator.

The specifications of electrical and electronic units:

Throttler servo: Hitec HS311, 3.5 kg.cm,0.11 sec/60 deg @ 6V

Rudder servo: Hitec HS485B, 6.41 kg.cm,0.18/60 deg @ 6V

Tilter servo: Hitec HS5565MH Digital Programmable Servomotor(metal

gear),11kg.cm,o.11s/60 deg @ 6V

Hitec Optic 5 channel transmitter and receiver



Chapter 11

SCOPE OF WIG CRAFT

12.1 Civil applications

According to a preliminary analysis, there exist encouraging prospects for developing

commercial ekranoplans to carry passengers and/or cargo, to be used for tourism and leisure

as well as for special purposes, such as search-and-rescue operations.

12.1.1 Search-and-rescue operations

An analysis of existing means of rescue on water shows that surface ships are unable

to come to the place of disaster quickly enough, while airplanes cannot perform effective

rescue operations because the airplanes cannot land close to a sinking ship. Even most

modern seaplanes have both lower payload and seaworthiness as compared to the

ekranoplans. The GE search-and-rescue vehicle „„Spasatel‟‟ is under construction at

„„Volga‟‟ plant in Nizhniy Novgorod.

12.1.2 Global Sea Rescue System

There is a worldwide concern to develop effective rescue measures on the high seas.

Experience shows that it is very difficult if not impossible to provide timely aid at wreckages

and ecological disasters at sea. Use of seaplanes is often limited because of unfavorable

meteorological conditions, whereas use of helicopters is restricted to coastal areas. Until now,



the main means of rescue (salvage) on water has been ships finding themselves accidentally

near the disaster area and hardly suitable for this purpose.

12.1.3 Other civil applications

Transportation of non-standard commercial payloads of large sizes and weights,

Search-and-rescue operations of large scale,

Transportation of perishable goods in quantity throughout the world,

High-speed luxury transportation,

Rapid response to international market fluctuations.

12.2 Naval application

Analysis of known projects and future naval applications have confirmed that the

above listed properties of ekranoplans together with their high surprise factor due to speed,

low radar visibility, sea keeping capability, payload fraction comparable to similar size ships,

dash speed feature and capacity to loiter afloat in the open ocean make them perfect multi-

mission weapons platforms which can be deployed forward and operate from tenders.

Naval ekranoplans can be used as strike warfare weapons against land and seaborne

targets, launch platforms for tactical and strategic cruise missiles, aircraft carriers and

amphibious assault transport vehicles. Easy alighting at moderate sea states makes it possible

to utilize ekranoplans as antisubmarine warfare planes capable of effectively deploying

hydrophones or towed arrays. They can also be used in a wide variety of reconnaissance and



transport roles. WIG effect vehicles could adapt themselves to an operational concept of

anchorages all over the world to maintain a forward posture.

12.2.1 Anti-surface warfare

Sustained sea-level operations of ekranoplans would reduce the horizon-limited

detection ranges of defending airborne early warning systems, significantly reducing warning

time. If the defender has no airborne early warning assets, mast height ship radars would not

see the ekranoplan until it almost reached its target.

From operational and tactical viewpoints, the ekranoplan has incontestable advantages

versus any other missile-carrying platform, in particular

Ekranoplan speeds exceed by an order of magnitude those of conventional surface

ships. Unlike aircraft, the ekranoplan is not tied to airports or aircraft carriers and can

be depressively based in any coastal area,

Unlike aircraft, the ekranoplan is less visible, flies in immediate proximity to the

water surface, and has large combat payloads. Due to its additional capability to

conduct flight operations far from the underlying surface, the ekranoplan can perform

self-targeting for larger ranges.



12.2.2. Anti-submarine warfare

The ekranoplan would be an effective platform for anti-submarine warfare (ASW),

being capable to detect, localize and destroy submarines at long ranges from their base. Its

significant payload capability would allow it to carry numerous sonobuoys, torpedoes and

mines. The ekranoplan could operate in a sprint-drift mode, alighting only to dip its sonar.

12.2.3. Amphibious warfare

The speed, payload and low-altitude cruising capabilities of the WIG would enable

devastating surprise assaults. The major difficulty with PAR-WIG amphibious operations is

the actual landing of men and equipment. Since reduced structural weight is a key factor

enabling efficient WIG flight, the vehicle cannot be reinforced to allow beaching without

deterioration of its cruise performance.

12.2.4. Sea lift

Ekranoplans are expected to be quite effective in providing a sealift function.

However, as shown by some estimates, in order to reliably brave high sea states, a trans-

oceanic WIG would need to be very large, at least 900 gross weight tons. Even so it is

estimated that one such WIG could deliver more cargo farther than three 300-ton C-5 aircraft-

and do this while using 60% less fuel.



12.2.5. Nuclear warfare

The performance characteristics of the WIG would make it suitable as a launch

platform for tactical and strategic cruise missiles. Its sea skimming cruise capability would

allow it to exploit gaps in low-altitude radar coverage. Furthermore, its sea loiter feature

would give it a flexibility not found in conventional strategic bombers. In fact, in a crisis, the

WIGs could deploy to mid-ocean and alight on the surface to maximize their survivability.

12.2.6. Reconnaissance and Patrol

Maybe, the weakest mission application for large WIGs would be in reconnaissance

or patrol. The limiting horizon resulting from low-altitude operation would greatly reduce

radar or signal intercept range, and therefore area coverage, to the point where it might not

represent a cost-effective use of the platform. Even in the strike warfare posture against ships,

WIGs would require targeting information from other platforms.



Chapter 12

COST REPORT

The expenses incurred as of date (for purchase, excluding transport and other petty charges)

NO PRODUCT DESCRIPTION QUANTITY EXPENSES(RS)

SuperTigre GS-45 Dual BB ABC w/Muffler 3 16000

1 Servomotors 6 6800

2 Carpentry and tool charges 5000

3 Wood- Mahogany 5 cubic feet 4900

4 Starter Motor (Tower Power Deluxe 12V starter

motor)

1 2400

5 Model engine fuel( 15 % nitro fuel) 4 litres 2400

6 Araldite gum 750 gm 1200

7 Tower Power Glow Plug 3 1100

8 Master Air screw Fibre glass propeller 9.5 X 6 inch 3 890

9 Engine Mount 3 800

10 Propeller spinner cone (2-inch Blazer spinner) 3 780

11 Fuel Filter 3 700

12 Aluminium sheet 0.5 mm gauge – 0.45 kg

0.3 mm gauge – 0.45 kg

630

13 Square fuel tank 3 610

14 Fuel tubing 3 520



17 Aluminium pipe 19 mm dia, 4 m length

15 mm dia, 8 m length

350

18 Paint 2.5 litres 300

19 M seal 500 gm 100

20 Bolts and screw 0.9 kg 90

TOTAL : 45570



Chapter 13

ADVANTAGES AND OPPORTUNITIES

As the craft will not be operated at high altitudes, the fuselage (or cabin) of the craft

need not be constructed for pressurization, as for commercial aircraft.

The WIG can be operated across shallows and does not need marked channels by

water depth or pre-designated navigation routes. Tidal conditions are also no problem

if a slipway and hard standing terminal apron is used.

Low visibility for radar and other electronic devices.

High payload capability compared to conventional vessels.

drag is very low once the craft has taken off from the water surface into ground effect,

enabling much higher cruise

Speed higher than other marine vehicles, and also a smaller speed loss during

operation over waves.

High fuel efficiency, low environmental emissions and low weight.

The specific fuel consumption SFC is improved for WIG compared with other high-

speed marine craft due to the ability to cruise at a much lower proportion of total

installed power.

The economic efficiency of WIG can compete with an airplane. At short range, the

lower fuel requirement for WIG can be translated into higher payload.



Chapter 14

CHALLENGES AND LIMITATIONS

Aerodynamic stability and control within very fine limits due to its proximity to the

water surface.

The challenge of designing a configuration of main hull, lifting wing(s) and

stabilizing surfaces to give minimum drag in all the modes from floating, possibly

hovering, through planing, to flying in ground effect.

To fly at a steady clearance height.

Varied operating conditions from low-speed waterborne operation, transitions to

planing and take-off, followed by ground effect operating mode and out-of-ground

effect mode for some special craft.

Speeds of up to 400 knots at low operating altitude, wave impact, take-off and landing

loads as well as bird strike all have to be taken into consideration in the design

process. Take-off and

Landing operations in rough water at speeds from 50 kph up to 150 kph involve

hydrodynamic forces much larger than experienced by all except the fastest marine

craft.

Obtaining reliable data during testing phase of the craft.

Due to the low-level flight, turbulence levels are high, particularly when flying over

rough water.

Rotating the complete propulsion unit imposes significant structural design challenges

especially with multiple units installed side-by-side. The dynamic loads due to gust or



water impact induced by the large mass of the propulsion units cantilevered outboard

can be difficult to handle, especially when they are mounted on rotating mechanism.

There are no WIG commercial service routes operated so far, even though the WIG

has been successfully operated and tested for more than 30 years.

Will require area outside normal navigation channels suitable for a water runway of

1,000–2,000 m in length and 500 m in width for take-off.

The collision risk for WIG is higher than that of conventional high-speed craft

because of its very high speed and operation essentially at ground level, so the

navigation equipment installed such as radar has to be responsive, precise, light and

reliable.

Setting up operations with a WIG service will require considerable vision on the part

of the operator and careful training of personnel.

For successful and safe commercial operations, the route of an established service

should be designated as a WIG route and documented on charts so that ships would be

warned of the presence of these high-speed craft.



Chapter 15

CONCLUSION

The most optimum wing configuration for the ground effect vehicle was obtained.

The research conducted so far shows that DHMTU airfoil is having superior lift performance

when compared to other airfoils. This might be due to the flat lower portion of the airfoil and

a S shaped camber line which provides stability in the ground effect region. It has also been

observed that as the proximity to ground increases that value of CL increases and hence lift

force increases, this is due to the increase in ram effect ie the amount of air trapped beneath

the airfoil increases hence increasing the difference between the amount of air below and

above the airfoil also there is reduction in drag of the airfoil due to span dominated ground

effect. The drawback of DHMTU is that out of ground effect it doesn‟t offer high lift as it

does in ground effect region contrary to this the value of CL for NACA 2412 out of ground

effect is 0.8 and in ground effect it was found out to be 0.72, same was the behaviour of other

airfoils. It was also observed that for small value of AOA at very high ground effect region

(h/c<=0.1) airfoil having convex bottom surface, there is occurrence of suction effect at the

bottom portion of the airfoil; it was also observed that the suction was not so high for

DHMTU airfoils. It was also observed that the DHMTU offers superior aerodynamic

efficiency at low AOA and has the maximum aerodynamic efficiency at 60 AOA. It was also

observed that the value of aerodynamic efficiency increases as the velocity of airflow

increases.

WIG is a transport technology that can deliver different craft with operating speeds

anywhere from 80 kmph up to 600 kmph and one where craft size can also be significantly



larger than aircraft. It has been rightly over 4 decades since the advent of the largest WIG

ever build- Caspian Sea Monster, the largest aircraft at the time.

But this hasn‟t now spawned into a great industry already. But the new century had

brought in hopes for the technology with Boeing too entering into the arena with its Pelican

project. A large-scale WIG development would be very capital intensive and so require major

government funding if it were to succeed, just as the Russian Ekranoplan development in the

1970s and 1980s. That program died when the government funding was unable to be

continued.

One requirement WIGs have taken some time to respond to is wave height capability.

While cruising, wave height is not so much of a problem, but if you can only take off and

land in rather small waves, it becomes quite difficult to plan long journeys where the seas

will exceed the landing criteria. Creating a very large model will cause a series of problems

such as air compression under the main wing in strong GEZ, aero-elasticity of the structure,

structural vibration, etc.

In order to get the WIG into commercial operation, a good deal of equipment,

facilities and regulations will need to be designed and agreed as standards, such as special

ground equipment, allocated air navigation zones close to terminals, agreed methods for

collision avoidance with marine craft and new safety codes for operation. Since the WIG is a

mixture of aviation, shipbuilding and air cushion industry technology, including both

aerodynamics and hydrodynamics, some novel problems will continue to be encountered as

craft designs evolve. In spite of all these, we fervently hope that this technology would one

day pioneer a new dawn into the maritime transport industry and this concept would one day

ply in the waters and would be a viable transport replacement for fast and large freight and

human transport.



REFERENCES

1. Kirill V. Rozhdestvensky, Wing-in-ground effect vehicles, Progress in Aerospace Sciences

42 (2006) 211–283

2. H.H. Chun, C.H. Chang, Longitudinal stability and dynamic motions of a small passenger

WIG craft, Ocean Engineering 29 (2002) 1145–1162

3. Liang Yun, Alan Bliault, Johnny Doo, WIG Craft and Ekranoplan, Ground Effect Craft

Technology, Springer Science+Business Media, LLC, 233 Spring Street, New York,

NY 10013, USA

4. F.Pérez-Arribas, Parametric generation of planning hulls, Ocean Engineering 81(2014)89–

104

5. Lawrence Benen, General resistance test of a stepless planning Hull with application to a

Hydrofoil configuration, August 27, 1965

6. Russell Barnes, Interpreting Line Drawings for Ship Modelling

7. E. P. Clement “Small Craft Data Sheet” SNAME BULLETIN 1-23 (1963)

8. Kyoungwoo Park and Juhee Lee, Influence of endplate on aerodynamic characteristics of

low-aspect-ratio wing in ground effect, Journal of Mechanical Science and Technology 22

(2008) 2578~2589

9. H. Wang, C. J. Teo, B. C. Khoo, C. J. Goh, Computational Aerodynamics and Flight

stability of Wing-In-Ground (WIG) Craft, Procedia Engineering 67 ( 2013 ) 15 – 24

10. Sang-HwanLee, JuheeLee, Aerodynamic analysis and multi-objective optimization of

wings in ground effect, Ocean Engineering68 (2013)1–13

11. M.R. Ahmed, S.D.Sharma, An investigation on the aerodynamics of a symmetrical airfoil

in ground effect, Experimental Thermal and Fluid Science 29 (2005) 633–647



12. Sungbu Suh, KwangHyo Jung and Ho Hwan Chun, Numerical And Experimental Studies

On Wing In Ground Effect, International Journal of Ocean System Engineering 1(2) (2011)

110-119

13. A.C. Kermode, Mechanics of Flight (Pearson Higher Education, 2012)

14. John D. Anderson, Introduction to Flight (Tata McGraw Hill, 2010)

design,analysis and fabrication of wing-in-ground effect vehcile

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