1. (DEEMED TO BE UNIVERSITY)
SCHOOL OF AERONAUTICAL SCIENCE
DEPARTMENT OF AERONAUTICAL ENGINEERING
HINDUSTAN INSTITUTE OF TECHNOLOGY AND SCIENCE PADUR, CHENNAI 603 103
MAY 2020
2. DESIGN OF TWIN ENGINE BUSINESS JET AIRCRAFT
AEB336 AIRCRAFT DESIGN PROJECT REPORT-I
Submitted by
GANESH NAGENDRAN â 17101001
VENKATA MAHESH REDDY â 17101002
DEEPIKA KUMARI â 17101003
CHIRAG GOYAL - 17101030
Under the guidance of
Mr. Elumalai
In partial fulfilment for the award of the degree Of
BACHELOR OF TECHNOLOGY
In
AERONAUTICAL ENGINEERING
3. Contents:
⢠Acknowledgement Slide - 5
⢠Abstract Slide - 6
⢠Dimensions of Various Aircrafts Slide -7
⢠Weight Configuration of Various Aircrafts Slide - 8
⢠Performance of Various Aircrafts Slide - 9
⢠Engine Configuration of Various Aircrafts Slide - 10
⢠Dimension Graphs of Various Aircrafts Slide - 11
⢠Weight Configuration Graphs of Various Aircrafts Slide - 12
⢠Performance Graphs of Various Aircrafts Slide - 13
⢠Engine Configuration Graph of Various Aircrafts Slide - 14
5. ACKNOWLEDGEMENT
First and foremost, we would like to thank the Almighty Lord for His presence and immense blessings through the project
work.
We wish to express my heartfelt gratitude to Dr R Asokan, Head of Department, School of Aeronautical Science for much of
his valuable support encouragement in carrying out this work.
We would like to thank my internal guide Mr. Elumalai, for continually guiding and actively participating in my project, giving
valuable suggestions to complete the project work.
We would like to thank all the technical and teaching staff of the School of Aeronautical Science, who extended directly or
indirectly all support.
Last, but not the least, we are deeply indebted to my parents who have been the greatest support while we worked day and
night for the project to it a success.
6. ABSTRACT
The business jets have a premium space in the aviation market. They range from small four-seated aircraft to converted huge
jumbo jets such as B 747. They vary in size and capacity. This report is about the design evaluation of a mid-sized business
jet for short range travel.
The main aim is to make a business jet that is comfortable and cost-effective within the design parameters as well as
technically efficient. The unique features of the aircraft include a canard and a ballistic parachute. The canards provide good
stall characteristics whereas the ballistic parachute stands as a backup in-case of an engine or any other failure. Thus, it acts
as a full proof back-up.
The report focuses on the aircraft design and business jets at the beginning. It comprises of a literature survey of about 20
existing medium business jets. The performance, specification and other parameters that are similar are compared and
analysed to finalize the ideal parameters for the aircraft. Weight estimation has been done to analyse empty weight, fuel
weight and overall take-off weight. Various airfoils are researched and analysed thoroughly to find an ideal airfoil and its
important parameters are calculated. The wing selection is done later as per the design demands.
Finally, performance graphs of the aircraft are drawn. This business jet is a 17-seater with a twin turbo-fan engine with a
cruising speed of 750mph.
15. ⢠Estimated Maximum Take-off Weight = 39000 lb = 17000 kg
⢠Estimated Fuel Weight Wf = Wf used + Wreserved
= 9867 lb = 4475 kg
⢠% Error = % Error = [{(WE ACT - WE TENT)/WE ACT } * 100]
= 1.3%
WEIGHT ESTIMATION
16. WING SELECTION
Selection of Number of wings: There are three types of wings that exist based on the
number of wings of an aircraft.
ďŹ Monoplane,
ďŹ Biplane,
ďŹ Triplane
Selected Type:
Monoplane. A monoplane is very efficient and less heavy than a biplane especially when the aircraft has higher cruise
speeds. The monoplane design eliminates lift induced drag and it also eliminates extra structural support mass needed to
support extra set of wings.
17. To support itself a wing has to be rigid and strong
and consequently may be heavy. By adding external
bracing, the weight can be greatly reduced. Two
types of wing support available: Cantilever and
semi-cantilever.
Selected Type:
Cantilever. The wings of most naval aircraft
are of all metal, full cantilever construction. The
wing can be fastened to the fuselage without the
use of external bracing, such as wires or struts. A
complete wing assembly consists of the surface
providing lift for the support of the aircraft.
Wing Support Wing Location
The wing may be mounted at various positions relative to the
fuselage:
ďŹ Low wing
ďŹ Mid wing
ďŹ Shoulder wing
ďŹ High wing
ďŹ Parasol wing
Selected Type:
Low Wing. A low wing enhances take off performance of
an aircraft. It lowers the drag of the aircraft as it a low wing
design has a lower cross-sectional area than a high wing design.
Low wing design is also lighter as the wing need not to be as
structurally reinforced as in a high wing design, struts are also
eliminated. The landing gear can be housed inside the wing box
0allowing more cabin space which is essential for a light
business jet. A low wing design also gives the aircraft more a
premium look which customers of business jets expect.
18. Tapper wings/Tapered Wings
Not all wings are rectangular. Another way to reduce drag while increasing strength is with a
trapezoid-shaped wing. Another name for this wing is a tapered wing. "To taper" means to make
something gradually smaller at one end.
Selected Type:
Tapper Wing. The wing is tapered at the end to avoid creation of high
vortices which causes drag and reduce the efficiency of the wing.
Dihedral
Anhedral
Selected Type:
Dihedral. Dihedral improves lateral (roll) stability of the aircraft. The placement of
wings at lowers side decreases the lateral stability to a small extent, this is to be
compensated by dihedral and additional lateral stability is to be provided, as for a civil
aviation aircraft stability is a desired feature.
Selection of Angle
19. Chime
Canards
Levcons
Selected Type:
Canard. The aircraft uses canard for pitch control. A lifting canard is used which distributes the load
between the wing and canard. The canard helps in allowing the aircraft to have apt centre of gravity and main
advantage of canard is its favourable stall recovery characteristics. The canard is of same profile as the wing and
is set at slightly higher angle of incidence than the wing such that during onset of stall the canard stall drops the
nose down and helping in stall recovery. The canard is also efficient than a conventional tail as it do not produce
downward force.
Auxiliary Control Surfaces
20. Airfoil Selection
Selection Criteria
⢠High Cl max.
⢠Low Cd min.
⢠High (Cl/Cd)max.
⢠Low pitching coefficient Cm.
⢠Stall Quality (Curve must be gentle not sharp).
⢠Thickness of Aerofoil.
⢠t/c selection
15 % to 18 % for low speed aircraft.
9 % to 12 % for high speed aircraft.
3 % to 9 % for supersonic aircraft.
21. Wing Setting Angle :
For Fighter ιset = 0° to 1°
For Commercial ιset = 3° to 5°
For Business Jet ιset = 2° to 4°
For our Business Jet, we set the value of ιset as 3°.
Wing Area (S): S = Max. Take-off Weight / Wing
Load = 25.45 m2
Aspect Ratio A.R: AR = b2 / S = 6.5
Chord Length c : c = b / AR = 1.97 m
Root Chord croot : 1.97 m
Tip Chord ctip : ctip = l * croot = 0.985 m
Mean Aerodynamic Chord MAC (Ä): Ä = [{(2/3)*cr
* (1+ l + l 2)/(1+ l )}] = 1.532 m
Structural Weight Volume : WF / ĎF = 1.774 m3
Chord Thickness Ratio (t/c) : 20% of wt. volume = (t/c) * Ä *
(0.5 * cr) * (0.5 * b)*1.5 = 0.03658
Root Thickness tr: tr = (t/c) * croot = 0.072
Tip Thickness tt: tt = (t/c) * ctip = 0.036
Wing Lift Coefficient CL : CL = [(2*WTO*g)/(Ď*v2
cruise*S)] = 0.2
Selected Airfoil
NACA 23024 is selected for wing root.
NACA 23012 is selected for wing tip.
22. TAIL PLANE SELECTION
⢠Conventional-Tail:
⢠Cruciform-Tail:
⢠T-tail:
⢠V-Tail:
⢠Triple-Tail:
⢠Twin boom:
⢠H-Tail:
⢠Tailless:
⢠Y-Tail:
Selected Type:
T-tail. Since T-tails keep the stabilizers out of the engine wake,
and give better pitch control. T-tails have a good glide ratio, and
are more efficient on low speed aircrafts.
23. LANDING GEAR SELECTION
Types
1. Fixed
2. Retractable
Selected Type:
Retractable. The retractability adds to
overall efficiency of the aircraft. The
retractable gear produces lower drag than
fixed ones and also permit aircraft to
cruise at high speeds.
Landing Gear Configuration
Single wheel landing Gear
⢠Bicycle
⢠Tricycle
⢠Quadricycle
⢠Multi-bogey
Selected type:
Tricycle. The Tricycle landing gear gives the
aircraft more stability than a unicycle or
bicycle landing gear and it also more
comfortable for occupants than tail draggers.
The tricycle is such that main landing gear
takes almost most of the force of landing.
This configuration is also less complex and
cheaper than fixed ones and also permit
aircraft to cruise at higher speeds.
24. FUSELAGE CONSTRUCTION
Construction Type:
⢠Monocoque
⢠Semi-Monocoque
⢠Geodesic Truss Construction
Selected type:
Semi-Monocoque Structure. Semi-Monocoque structure
offers higher strength to weight ratio than other forms of aircraft
structure. It distributes the load between the skin and the
structure it is lighter than the Monocoque aircraft structure and
it is most preferred aircraft structure.
25. ENGINE SELECTION
Types of Engine:
⢠Reciprocating
⢠Turbofan
⢠Turbojet
⢠Turboprop
⢠Ramjet
⢠Scramjet
⢠Pulsejet
⢠Turboshaft
Selected Type:
Turbofan. Turbofan engines are most efficient
aircraft engines for high subsonic speeds. They
are fuel efficient and have lower emission than
other types of jet engines. They also have less
acoustic signature, well within the current airport
standards.
26. Location of Engine
⢠Nose mounted
⢠Wing mounted Below the wing
⢠Above the wing
⢠Close to Fuselage
⢠Centre of the Wing
1. Tail mounted
2. Engine mounted
Selected Type: Engine Mounted. The twin
turbofan engine is mounted at the rear of the
aircraft and is buried inside the fuselage. This
eliminates and need for a wing pylon or other
external engine mounting fitting or extensions.
This in turn reduces cross sections of the
aircraft and also reduced the drag. The inline
engine mounting also eliminates the need to
have a nonzero thrust angle which prevents loss
of power due to engine thrust angle offset.
Number of Engines: Twin Engine
Thrust Value:
T = {Total Thrust (from graph) +10% of Total Thrust}/No. of Engines
T = (24000+24000*10/100)/2
T = 13200 Newton per engine
Total Thrust = 13200 * 2 = 26400 Newton
Selection of Engines
S.No Engines Maximum Thrust Weight
Specific Fuel
Consuption Length Diameter
KN Kg Kg/Kn/h m m
1 WILLIAMS FJ44-3A 26.6 243 91.39 1.22 0.58
2 PWJT15D 18.6 223.5 72.85 1.53 0.68
3 GE J610-6 27.6 211 98.91 1.3 0.45
Selected Type:
WILLIAMS FJ44-3A
28. LIFT AND DRAG CALCULATION
1. Lift calculation:
Lift during Takeoff L = (Ď*v2*s*CLmax)/2 = 6.82 KN
Lift during cruise L = 1/2 * Ď * v2 * s * Clmax =84.56 KN
Lift during Landing L =1/2 * Ď * v2 * s * Clmax =6.834 KN
2. Drag Calculation:
Drag during Take-off D = 1/2 * Ď * v2 * s * CD = 0.746 KN
Drag during cruise D = 1/2 * Ď * v2 * s * CD = 3.076 KN
Drag during Landing D = 1/2 * Ď * v2 * s * CD = 0.828 KN
PERFORMANCE CALCULATION
Rate of climb R/C = [(Pa - Pr)/W] = 57.07 m/s
Rate of sink R/S = [(2*W/Ď)1/2 * (CD/CL)3/2] = 7.6 m/s
Take-off distance sLO = [(1.21 * WTO) / (g * Ď *s * CLmax
* (T/W))] = 21678.41 m.
Landing distance sL =
[{(1.69*W2)/(g*Ď*S*CLmax*(D+Âľr(W-L)))}] = 521.5 m
29. CONCLUSION AND FUTURE WORKS
The preliminary design of twin engine business jet aircraft is done and the various design considerations and performance parameters
required are calculated and found out. The obtained design values are not necessarily a define reflection of the airplaneâs true and
conceptualized design, but the basic outlay development has been obtained.
The final design stays true to the desired considerations of the business jet aircraft that can provide high performance and considerable
reduction in run-way distance. Also, it has a considerable value of TSFC as well. This is no ideal design and is highly subjected to
improvisations and innovations to make the design as ideal as possible.
During the onset of our work we faced various phases of the project that made us understand how challenging the process of designing is so
as to make a perfect design. A lot of efforts have been put into this project and as much as we have learnt at the same time.
In the future the design elements will be put into more of tests. The structure of the aircraft will be more refined. Analysis of various
components of the aircraft will be performed. A finite element analysis (FEA) on aircrafts structure is to be done and various structural
materials and components will be undertaken to find ideal elements and material for aircrafts performance.
Computational fluid simulations will be conducted on the wings and the whole aircraft as well to further refine the design. The next step
would be wind tunnel testing of the aircraft at various flight regimes. Then the final structure and specification of the aircraft will be
finalized which will be ideal first prototype.
We will also be continuing the structural analysis in the next year in aircraft design project 2
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