This document is a case study report on winglets submitted by a student. It includes an introduction describing the purpose and contents of the report. The main body is divided into chapters that describe the history of winglets, how they work to reduce wingtip vortices and drag, their aerodynamic effects such as improving the lift distribution, and the importance of an elliptical lift distribution. Evaluation rubrics are also included.

1. A Case Study Report on
“WINGLETS”
Submitted by
Student name -AYUSH KUMAR
USN: 1NT19AE007
to
Mr. Prashant Manvi
Assistant Professor
Department of Aeronautical Engineering
Subject Name: Aircraft Performance
Subject Code: 18AE51
Academic Year: 2021-22
NITTE MEENAKSHI INSTITUTE OF
TECHNOLOGY
An Autonomous Institution Approved by UGC/ AICTE/ Govt. of
Karnataka.
Accredited by NAAC-UGC with "A+" grade, UG Programs,
Accredited by NBA (Tier-1), Affiliated to VTU, Belagavi.
Yelahanka, Bengaluru - 560 064, India.

2. Industrial Aerodynamics
Rubrics for Evaluation of the Case study
Student Name: 18AE51 Aircraft Performance USN: 1NT19AE007
Date:12/01/22
Knowledge and
Content
Inadequate Average Admirable Outstanding Score
4 6 8 10
Organization of
presentation
Hard to follow;
sequence of
information jumpy
Most of information
presented in
sequence
Information presented
in logical sequence;
easy to follow
Information
presented as
interesting story in
logical, easy to
follow sequence
Background content Material not
clearly related to
topic or
background
dominated seminar
Material sufficient
for clear
understanding but
not clearly
presented
Material sufficient for
clear understanding and
effectively presented
Material sufficient
for clear
understanding and
exceptionally
presented
Methods Methods too brief
or insufficient for
adequate
understanding or
too detailed
Sufficient for
understanding but
not clearly
presented
Sufficient for
understanding and
effectively presented
Sufficient for
understanding and
exceptionally
presented
Contribution of
work
Significance not
mentioned or just
hinted
Significance
mentioned
Significance explained Significance
exceptionally well
explained
Knowledge of
subject
Does not have
grasp of
information;
answered only
rudimentary
questions
At ease with
information;
answered most
questions
At ease; answered all
questions but failed to
elaborate
Demonstrated full
knowledge;
answered all
questions with
elaboration
Presentation Skills Mumbles and/or
Incorrectly
pronounces some
terms Voice is low;
difficult to hear
Incorrectly
pronounces some
terms Voice
fluctuates from low
to clear; difficult to
hear at times
Incorrectly pronounces
few terms Voice is
clear with few
fluctuations; audience
can hear well most of
the time
Correct, precise
pronunciation of
all terms Voice is
clear and steady;
audience can hear
well at all times
Graphics Uses graphics that
rarely support text
and presentation
Uses graphics that
relate to text and
presentation
Uses graphics that
explain text and
presentation
Uses graphics that
explain and
reinforce text and
presentation
Total Marks obtained out of 10
NITTE MEENAKSHI INSTITUTE OF TECHNOLOGY
(An Autonomous Institution under Visvesvaraya Technological University, Belgaum)
Yelahanka, Bangalore
Department of Aeronautical Engineering

3. Guide lines for preparation of Case study
report
1. Case study report should be typed neatly only on one side of the paper with 1.5 or double line spacing on a
A4 size bond paper (210x297 mm). The margins should be: Left – 1.25”, Right – 1”, Top and Bottom –
0.75”. Font: Times new Roman
2. Report to be submitted to concern faculty on or before 14th January 2022.
3. the report must contain
 Title page
 One Rubrics evaluation sheet per student in the format enclosed (with filled details)
 An Abstract (Synopsis)not exceeding 100 words, indicating salient features of the work.
 Table of Contents
 List of table & figures (optional)
 Chapters (to be numbered in Arabic) containing Introduction. Which usually specifies the scope
of work and its importance and relation to previous work and the present development. Main
body of the report has to be divided appropriately into chapters, sections and sub-sections.
 The chapters, sections and subscriptions may be numbered in the decimal form for e.g.
Chapter2, sections as 2.1, 2.2 etc., and sub-section as 2.2.3,2.5.1 etc.
 The chapter must be left justified (font size 16) followed by the title of chapter centered (font
size 18), section/subsection numbers along with their headings must be left justified with
section number and its heading in font size 16 and sub-section and its heading in font size14.
The body or the text of the report should have font size 12.
 The figures and tables must be numbered chapter wise for e.g.: Fig. 2.1 Block diagramof a serial
binary adder, Table 3.1 Primitive flow table, etc.
 The last chapter should contain the summary of the work carried, contributions if any, their
utility along with the scope for further work.
 Reference OR Bibliography: The references should be numbered serially in the order of their
occurrence in the text and their numbers should be indicated within square brackets for e.g.[3].
The section on reference should list them in serial order in the following format.
 For textbooks – A V. Oppenheim and R.W. Schafer, Digital Signal Processing, Englewood,
N.J., Prentice Hall, 3 Edition, 1975.
 For papers – Devid, “Insulations design to combat pollution problem”, Proc. of IEEE, PAS,
Vol. 71, Aug 1981, pp. 1901-1907.
 Only SI units are to be used in the report. Important equations must be numbered in decimal
form for e.g. V = IZ ………. (3.2)
All equation numbers should be right justified.

4. CONTANT:
1)HISTORY OF WINGLETS
2)How does it work?
3)Aerodynamic effects
4)What are wingtip vortices?
5)IMPORTANCE OF HAVING AN ELLIPITICAL
AIR DISTRIBUTION AROUND THE
WINGSPANE?

5. HISTORY OF WINGLETS:
Wingtip devices are intended to improve the efficiency
of fixed-wing aircraft by reducing drag.Although there are
several types of wing tip devices which function in
different manners, their intended effect is always to
reduce an aircraft's drag by partial recovery of the tip
vortex energy. Wingtip devices can also improve aircraft
handlingcharacteristics and enhance safety for following
aircraft. Such devices increase the effective aspect ratio of
a wing without greatly increasing the wingspan.
Extendingthe span would lower lift-induced drag, but
would increase parasitic drag and would require boosting
the strength and weight of the wing. At some point, there
is no net benefit from further increased span. There may
also be operational considerationsthat limit the allowable
wingspan .

7. How does it work?
Winglets reduce wingtipvortices, the twin tornados formed by the
difference between the pressure on the upper surface of an airplane's wing
and that on the lower surface. High pressure on the lower surface creates a
natural airflow that makes its way to the wingtipand curls upwardaround
it. When flow around the wingtips streams out behindthe airplane, a vortex
is formed. These twisters representan energy loss and are strong enough
to flip airplanes that blunder into them.
Winglets produce an especiallygood performance boost for jets by
reducingdrag, and that reduction could translate into marginallyhigher
cruise speed. But most operators take advantage of the drag reduction by
throttling back to normal speed and pocketing the fuel savings.
Several airliners use them. The Airbus A319 and A320 have very small upper
and lower winglets. The longer-range twin-engine A330 and four-engine
A340 have conventional winglets, as do Boeing 747-400s. Aviation Partners,
a Seattle, Washington company, has a new design it calls a "blended"
winglet. The BoeingBusiness Jet (opposite, top), a derivative of the Boeing
737, has a set of the firm's eight-foot winglets with a curvingtransition
from wing to wingletthat is characteristicof the company's design.
In 1976, shortly after an energy crisis sent fuel prices skyward, Richard
Whitcomb, a NASA aerodynamicist, publisheda paper that compareda
wing with a winglet and the same wing with a simple extension to increase
its span. As a basis for comparingboth devices, the extension and the
wingletwere sized so that both put an equal structural load on the wing.
Whitcomb showedthat winglets reduceddrag by about 20 percentand
offered double the improvement in the wing's lift-to-dragratio, compared
with the simple wingextension.

8. Aerodynamic effects:
The use of winglets leads to a splitting of the tip
vortex. The vortex is displaced and reappears in a
smallerform at the winglet tip. The smallervortex
has a lower rotational speed and less kinetic energy
and thus a reductionof the induced drag. As a result
of the damped induced drag, the influenceon the lift
decreases.Thus, as the drag decreases,the lift
distribution approaches the optimal elliptical
distribution.The damping of the vortex results in a
weakening of the dangerouswake vortices in the
near field of the aircraft. In additionto the effects
mentioned above, a winglet reduces the stall speed,
i.e. that speed which must at least be present in
order to generate usablelift.

9. What are wingtip vortices?
They're swirling tunnels of air that form on your wingtips. High-pressure air
from the bottom of your wing escapes around the wingtip, moving up
towards the lower pressure area on the top of the wing. This movement
creates a vortex or tunnel of air, rotating inwards behind the wing.
They're strongestwhen the air pressure difference betweenthe top and the
bottom of the wing is the greatest - which happens when you're generating
the most induced lift. This occurs when you're at high angles of attack.
During takeoff and landing, you're slow - so you're at a high angle of attack
and generating strong wingtip vortices.
When you're cruising at high altitudes, like a jet in the flight levels, the air is
thin. So, you need a high angle of attack to generate enough lift to stay
level, even though you're moving fast. Your wingtip vortices are stronger
here, too.

10. IMPORTANCE OF HAVING AN ELLIPITICAL AIR DISTRIBUTION
AROUND THE WINGSPANE?
Theoretically, the most efficient way to create lift is to generate it
in an elliptical spanwise distribution across the wing. There is no
inherent superiority to pure elliptical shapes, and wings with
other planforms can be optimized to give elliptical spanwise lift
distributions.
The basic elliptical wing shape also has disadvantages:
The almost uniform lift distribution of a constant-aerofoil section
elliptical wing can cause the entire span of the wing
to stall simultaneously, potentially causing loss of control with
little warning. To improve the stalling characteristics and give the
pilot some warning, designers use a non-uniform aerofoil. For
example, the wing of the Supermarine Spitfire was both thinned
towards the tips and twisted to give washout, reducing the load on
the tips so that the inner wing would stall first.

11. THANK YOU