Design, Fabrication and Testing Of Flapping Wing Micro Air Vehicle

K.P.Preethi et al. Int. Journal of Engineering Research and Applications www.ijera.com
ISSN: 2248-9622, Vol. 6, Issue 1, (Part – 3) January 2016, pp.133-150
www.ijera.com 133|P a g e
Design, Fabrication and Testing Of Flapping Wing Micro Air
Vehicle
K. P. Preethi Manohari Sai1
, K. Bharadwaj2
, K. Ravi Teja3
, Kalyan Dagamoori4
,
Kasiraju Venkata Sai Tarun5
, Vishnu Vijayan6
1,2,3,6
B.Tech Student, Department Of Aeronautical Engineering, MLR Institute Of Technology,
Dundigal, Hyderabad. INDIA.
4
B.Tech Student, Department Of Aeronautical Engineering, MLR Institute Of Technology and Management,
Dundigal, Hyderabad. INDIA.
5
B.Tech Student, Department Of Aeronautical Engineering, GITAM UNIVERSITY, Hyderabad. INDIA.
ABSTRACT:
Flapping flight has the potential to revolutionize micro air vehicles (MAVs) due to increased aerodynamic
performance, improved maneuverability and hover capabilities. The purpose of this project is to design and
fabrication of flapping wing micro air vehicle. The designed MAV will have a wing span of 40cm. The drive
mechanism will be a gear mechanism to drive the flapping wing MAV, along with one actuator. Initially, a
preliminary design of flapping wing MAV is drawn and necessary calculation for the lift calculation has been
done. Later a CAD model is drawn in CATIA V5 software. Finally we tested by Flying.
Keywords : Flapping wing mav, Ornithopter, Components of MEMS etc.
I. INTRODUCTION :
An ornithopter( from Greek ornithos "bird" and
pteron "wing") is an aircraft that flies by flapping its
wings. Designers tend to imitated by the flapping-
wing flight of birds, bats, and insects. Through
machines may differ in form, they are usually built
on the same scale as these flying creatures. Manned
ornithopter have also been, and some have
successful.Anornithopter is an aircraft that flies by
flapping its wings. Inspired by nature, we intend to
design our own ornithopters by studying the
kinematics and dynamics of flapping wing. Also, to
fabricate the remote controlled flapping wing MAV.
A gear box is needed to be constructed to bring
down the rpm to a reasonable value so that the wing
flapping frequency becomes 2-4 Hz. Next we need
harness the vertical velocity of the rotating gear
using the simple concept of simple harmonic motion.
In aircraft, tail is used for the pitch and yaw motion
whereas in ornithopter tail is used for pitch motion.
The ornithopter can be used for various kind of
spying and surveillance by fabricating better
construction material and gears.Ornithopter can be
used for military application, such as aerial
reconnaissance without alerting the enemies that
they are under surveillance as they can be resembled
into birds or insects.
1.1 History
The ancient Greek legend of Daedalus (Greek
demigod engineer) and Icarus (Daedalus's son) and
The Chinese Book of Han(19 AD) both describe the
use of feathers to make wings for a person but these
are not actually aircraft. Some early manned flight
attempts may have been intended to achieve
flapping-wing flight though probably only a glide
was actually achieved. , Leonardo da Vinci began to
study the flight of birds.
He grasped that humans are too heavy, and not
strong enough, to fly using wings simply attached to
the arms. Therefore he sketched a device in which
the aviator lies down on a plank and works two
large, membranous wings using hand levers, foot
pedals, and a system of pulleys.
Fig 1.1.1 Leonardo da Vinci's Ornithopter Design
The first ornithopters capable of flight were
constructed in France. Jobert in 1871 used a rubber
band to power a small model bird. Alphonse
RESEARCH ARTICLE OPEN ACCESS

Penaud, Abel Hureau de Villeneuve, and Victor
Tatin, also made rubber-powered ornithopters during
the 1870s. Tatin's ornithopter was perhaps the first to
use active torsion of the wings, and apparently it
served as the basis for a commercial toy offered
by Pichancourt c. 1889. Gustave Trouve was the first
to use internal combustion and his 1890 model flew
a distance of 70 metres in a demonstration for the
French Academy of Sciences. The wings were
flapped by gunpower charges activating a bourbon
tube.
1.2 Manned Flight
Manned ornithopters fall into two general categories:
Those powered by the muscular effort of the pilot
(human-powered ornithopters), and those powered
by an engine.
Otto Lilienthal in 1894, an aviation pioneer became
famous in Germany for his widely publicized and
successful glider flights. Lilienthal also studied bird
flight and conducted some related experiments. He
constructed an ornithopter, although its complete
development was prevented by his untimely death
on the 9th of August 1896 in a glider accident.
Fig. 1.2.1 Otta Lilienthal on August 16, 1894 with
his kleinerSchlagflügelapparat
AlexendraLippisch in 1929, a man-powered
ornithopter designed by him(designer of the Me163
Komet) flew a distance of 250 to 300 metres after
tow launch. Since a tow launch was used, some have
questioned whether the aircraft was capable of flying
on its own. Lippisch asserted that the aircraft was
actually flying, not making an extended glide.
(Precise measurement of altitude and velocity over
time would be necessary to resolve this question.)
Most of the subsequent human-powered ornithopters
likewise used a tow launch, and flights were brief
simply because human muscle power diminishes
rapidly over time.
Adalbert Schmid in 1942, made a much longer
flight of a human-powered ornithopter at Munich-
Laim. It travelled a distance of 900 metres,
maintaining a height of 20 metres throughout most
of the flight. Later this same aircraft was fitted with
a 3 hp (2.2 kW) Sachs motorcycle engine. With the
engine, it made flights up to 15 minutes in duration.
Schmid later constructed a 10 hp (7.5 kW)
ornithopter based on the Grunau-Baby IIa sailplane,
which was flown in 1947. The second aircraft had
flapping outer wing panels.
A team at the University of Toronto Institute for
Aerospace Studies , headed by Professor James
DeLaurier, worked for several years on an engine-
powered, piloted ornithopter. In July 2006, at the
Bombardier Airfield at Downview Park in Tronto,
Professor DeLaurier's machine, the
UTIASOrnithopter No. 1 made a jet-assisted takeoff
and 14-second flight. According to DeLaurier, the
jet was necessary for sustained flight, but the
flapping wings did most of the work.
Todd Reichert of the University of Toronto Institute
for Aerospace Studies, on august 2, 2010 has piloted
a human-powered ornithopter named Snowbird.
The 32-metre (105 ft 0 in) wingspan, 42-kilogram
(93 lb) aircraft was constructed from carbon fiber,
balsa, and foam. The pilot sat in a small cockpit
suspended below the wings and pumped a bar with
his feet to operate a system of wires that flapped the
wings up and down. Towed by a car until airborne, it
then sustained flight for almost 20 seconds. It flew
145 metres with an average speed of 25.6 km/h
(7.1 m/s). Similar tow-launched flights were made in
the past, but improved data collection verified that
the ornithopter was capable of self-powered flight
once aloft.
1.3 Applications for unmanned ornithopters
Practical applications capitalize on the resemblance
to birds or insects. He Colorado Division of Wildlife
has used these machines to help save the endangered
Gunnison Sage Grouse. An artificial hawk under the
control of an operator causes the grouse to remain on
the ground so they can be captured for study.
AeroVironment, Inc., then led by Paul B MacCready
( Gossamer Albatross)developed in the mid-1980s,
for the Smithsonian Institution, a half-scale radio-
controlled replica of the giant
pterosaur,Quetzalcoatlusnorthropi. It was built to
star in the IMAX movie On the Wing. The model
had a wingspan of 5.5 metres (18 feet) and featured
a complex computerized autopilot control system,
just as the full-size pterosaur relied on its
neuromuscular system to make constant adjustments
in flight.
Researchers hope to eliminate the motors
and gears of current designs by more closely
imitating animal flight muscles. Georgia Tech
Research Institute's Robert C. Michelson is
developing a Reciprocating Chemical Muscle for use
in micro-scale flapping-wing aircraft. Michelson
uses the term "entomopter" for this type of
ornithopter. SRI International is developing
polymerartificial muscles which may also be used
for flapping-wing flight.

1.4 Successful flapping wing MAVs
Percival Spencer constructed a series of engine-
driven ornithopters in the shape of a bird. They
ranged in size from a small 0.02-engine-powered
ornithopter to one with an eight-foot wingspan.
Spencer is also noted as a pioneer pilot and the
designer of the Republic Seabee amphibious
airplane. He also designed a toy, called the Wham-O
Bird, which introduced thousands of children to the
idea of mechanized flapping-wing flight.
Fig. 1.4.1 Wham-O Bird
Sean Kinkade'sSkybird, based somewhat on the
Spencer Seagulls and using a 0.15 methanol-fueled
engine, was an attempt at small-scale commercial
production of an RC ornithopter. Smaller, electric
versions were later offered. Unfortunately, many
would-be enthusiasts paid their money and never
received the product.
Fig. 1.4.2 Skybird
Several successful fabrication of flying birds
including hovering bird with wing span of 30cm to
100cm. The project, aims at taking this research
forward by building an autonomous, 1.5m wing span
flying bird which will carry a small camera as
payload and will able to take pictures for
surveillance.
Fig. 1.4.3 IIT Kanpur developed flapping wing
MAV
Robert Musters began a series of RC ornithopters
with foam, actively twisted wings. The appearance
of these ornithopters is close to that of a real bird
and they are being offered for use in bird control at
airports.
Fig. 1.4.4 Robert Muster's Ornithopter
II. LITERATURE SURVEY :
Alphonse Penaud, in 1870's performed a mechanical
flapping wing rubber powered model ornithopter in
France, which was documented and witnessed.
Alexander Lippisch also worked on ornithopters[1].
During 1990's The Project Ornithopter engine
powered piloted aircraft was which is base on the
techonolgy of the Harris/DeLaurier model. One of
the first successful attempts to develop bird- like
flapping flight was by DeLaurier[2].
The first MAVs were developed as early as WW-I in
the form of guided munitions later expanding their
roles into radio controlled target drones,
reconnaissance aircraft and glide bombs of the
modern day cruise missile[3]. The first radio
controlled(RC) aircraft flight in Germany 1936 led
the way to further refinement of small UAVs in post
war era. The air flow field in flapping wings can not
be assumed as steady. A large angle of attack would
lead to flow separation and turbulences too.
Obviously, there must be phenomena producing

extra lift. As was discovered with the development
of MEMS technology, the physics of the small are
different from that of the large (for example, friction
is more important than gravity) [4]. For MEMS
technology to progress, researchers had to develop a
new understanding of these physics, and develop
new techniques for overcoming and capitalizing on
them. This is the case with small scale, or low Re
aerodynamics today.
Fig. 2 Components of MEMS
2.1 Mechanics of Bird
Bird flight is one of the natural example of flapping
flight. For the birds, the feather on their wing s are
instrumental in their achieving flght, both the
prouslionand the efficient aerodynamics[5]. There
are two sets of feathers on a bird's wing, namely the
primary and secondary feathers. The primary
feathers are attached to the hard bones, and are
found on the hand section. Flight will be impossible
without the primary feathers. The secondary
feathers, which are inserted along the arm, which is
the inner wing, are responsible for lift. The bird is
able to enjoy much freedom of movement during
flight because of the wing’s ability to have its shape
altered, which is the result of each feather
functioning independently.
During flapping flight, the inner wing gives lift
whilst the hand section provides thrust [6] The inner
part of a bird’s wing remains relatively stationary
and acts as an aerofoil, producing lift and drag [7].
On the backstroke, which is the power stroke, the
primary feathers are linked together to produce a
near perfect aerofoil. Since the outer part of the wing
is more mobile, it can be twisted so that the wing
points into the airstream; as with all aerofoils, forces
are generated and maximum thrust and minimum
drag is obtained in addition to lift.On the upstroke,
the primary concern is to reduce drag. This is
achieved through different mechanisms for different
species of birds. On the smaller birds, the primary
feathers are separated, allowing air to pass through
and thus considerably reducing drag [6]. For the
larger birds or small but long-winged birds, their
wings are typically either flexed or partially closed
on the upstroke.
2.2 Experimental Studies
Wing Frequencies were observed in the field for 32
morphologically diverse bird species, representing
18 families and ranging in mass from 20g to nearly
5kg. A combination of multiple regression and
dimensional analysis was used to show that wing
frequency(f) may be estimated by:
)(08.1 3/14/112/13/1 
 Sbgmf
where m is the bird's body mass, g is the acceleration
due to gravity, b is the wing span, S is the wing area
and ρ is the air density[8].
An experimental study was conducted to assess the
aerodynamic benefits of flapping compared with
fixed soaring flight for the development of flapping
wing Micro Air Vehicle(MAVs). The time averaged
aerodynamic performance(i.e. a flexible nylon wing
and a very flexible latex wing ) were compared with
that of a conventional rigid wing to evaluate the
effects of skin flexibility of the tested wing son their
aerodynamic performance for flapping flight
application[9].
In the present, an experimental investigation was
conducted to assess the aerodynamics benefits of
using flexible membrane airfoil/wings for flapping
wing MAV applications. The time averaged lift and
thrust generated by flapping two flexible with
different skin flexibility were compared with those
of a conventional rigid wing to quantify the effects
of the skin flexibility of the tested wings on their
aerodynamic performances[9].
2.3 Computational Studies
Micro Air Vehicles (MAVs) by virtue of their small
size and maneuverability can provide an
indispensable vehicle for advance surveillance and
reconnaissance missions. MAVs by equirement are
compact with dimensions less than 15-20 cm and
flight speeds of around 10-15 m/s with gross takeoff
weights of 200g or less and which operate in the low
Reynolds number (10,000-100,000) regime. At these
low Reynolds numbers, the aerodynamic efficiency
(lift to drag ratio) of conventional fixed airfoils
rapidly deteriorates due to boundary layer separation
and early onset of stall[10].
Vortex wake effects were also accounted for in the
model that DeLaurier (1993a) developed. His
computational model for the unsteady aerodynamics
of root-flapping wing was based on the modified
7

strip theory approach, which made use of the
concept of dividing the wing into a number of thin
strips. This enabled the study of the wing as a set of
aerofoils next to one another by assuming no
crossflow between the strips or sections. Vortex-
wake effects were accounted for using modified
Theodorsen functions. In addition, this model
differed from previous work in that camber and
leading edge suction effects, as well as post stall
behaviour, were also accounted for. The analysis
was based on the assumptions that the flapping wing
is spanwise rigid, has high wing aspect ratio such
that the flow overeach section is essentially
chordwise, and that the wing motion is continuous
sinusoidal with equal times between upstroke and
downstroke. The model allowed the calculation of
average lift, thrust, power required and propulsive
efficiency of a flapping wing in equilibrium flight. A
numerical example was demonstrated to predict the
performance of a mechanical flying Pterosaur
replica, constructed by AeroVironment (1985), and
the results were presented.
Shyyet al. (2000) studied and reviewed the
computational model proposed by DeLaurier
(1993a). They performed computations for the
mechanical flying Pterosaur replica using a Matlab-
code developed based on the model and the results
are compared with those presented by DeLaurier.
They further investigated the performance of smaller
biological bird species, with results presented. They
also studied the effects of aerodynamic parameters
such as the flapping axis angle, maximum flapping
angle amplitude and dynamic twist of the wing, on
the performance of the biological flapping flight. In
addition, the authors developed an optimization
procedure for obtaining maximum propulsive
efficiency within therange of possible flying
conditions. However, flexing of the biological
wings, which tend to produce useful aerodynamic
benefits, have yet been incorporated since the model
used assumes that the wing is spanwise rigid.
KINEMATICS OF FLAPPING WING :
Human has a desire to fly like the flying biosystems
such as the insects and bird through engineering to
meet the motivational creativity and a hundreds of
years dream shown in Leonardo Da Vinci's drawing
of Otto Lilitenthal's gliders, to modern aircraft and
present flapping wing research.
3.1 Aerodynamics of Flapping Wing
Flapping aerodynamics is studied as an unsteady
aerodynamic flow. As for larger bird, the flapping
rate is low whereas for smaller bird and insects rate
is more due to highly unsteady aerodynamics and
lesser trailing vortices. Small birds and insects has to
work harder to producer the trailing vortices, to
increase the viscous flow regime. To enhance the lift
bird and insects has several other mechanisms are
been used such as Clap and Fling Mechanism Wake
Capture, Rapid Pitch Up and Delayed Stall[12].
Kinematics of Wing
The flapping wing motion ornithopters and
entomopters can have three basic motion with
respect to axis based on the kinematics motion of
wing and mechanism of force generation a) Flapping
, which is up and down plunging motion of the wing
. Flapping produces the majority of the bird's or
insect's power and has the largest degree of freedom.
b) Feathering is the pitching motion of wing and can
vary along the span. c) Lead-Lag, which is in-plane
lateral movement of wing[12].
Fig. 3.1.1 Moments on Wing
Flapping Wing Forces
Flapping motion involves two stage: the Down
Stoke, which provide the majority of the thrust and
the Up stoke which can also (depending on the birds
wing) provide some thrust. At some thrust at each
up-stroke the wing is slightly folded inwards to
reduce the energetic cost of flapping with flight .
Birds change the angle between the up stroke and
the down stroke of their wing. During the down
stroke of their wing. During the down stroke the
angle of attack is increased and is decreased during
the up stroke.
Fig 3.1.2. Forces acting on Flapping Wing

During the down stroke the total aerodynamic force
is tilted forward and has two components, lift and
thrust. During up stroke, the AOA is always positive
near the root but at the tip it can be positive or
negative depending on the amount of pitching up of
wing. Therefore, during up stroke the inner part of
wing produces aerodynamic force which is upward
but tilted backwards producing lift and negative
thrust. The outer region of the wings would produce
positive lift and drag if the AOA is positive. But if
AOA is negative then it will produce negative lift
but positive thrust [12]. Both cases are depicted in
the fig. 3.1.2.
3.2 Flapping Frequency
In the present research, Pennycuick has made some
observations in the flapping frequency which has
been considered. Pennycuick found out multiple
regression and dimensional analysis by conducting
an experimental studies on 32 morphologically
diverse bird species, representing 18 families, and
ranging mass from 20g to 5kg.The wingbeat
frequency is correlated by the following formula
)(08.1 3/14/112/13/1 
 Sbgmf
where m is the bird's body mass, g is the acceleration
due to gravity, b is the wing span, S is the wing area
and ρ is the air density[8].
The relationship between flight speed & the mass of
the bird can be given by from Pennycuide,
where m is
the mass of
the bird and
U is the flight
speed.
From Greenwalt computed statistical data,
54.316.1
lf
where, f is flapping frequency and l wing length(cm)
.
While Azuma showed the relation,
3
1
6
1
7.28)(
3.116)arg(




mbirdssmallf
mbirdself
where f is flapping frequency and m is mass of bird.
3.3 Aerodynamics Calculations
This procedure basically follows pitching-flapping
motion of rigid wing that is a structured adaptation
and simplification of the procedure adopted by
DeLaurier , Harmon, Malik et al. and Zakaria et al.
Fig 3.3.1. Front View of Flapping Wing
Flapping angle varies β as sinusoidal function. β and
its rate are given by following equations. The degree
of freedom of the motion is depicted in Fig. 3.
Flapping angle β varies as sinusoidal function. The β
angle and its rate and pitching angle θ are given by
)2(cos
)(
)(
2sin2)(
2cos)(
0
.
m ax







tf
B
ir
t
tftft
tft
where, 0
is the pitching motion , β(t) is the
flapping angle and )(
.
t is the flapping rate.
The horizontal and vertical components of relative
wind velocity as under:-
)))cos(...75.0())cos(.).(()sin(
))sin(...75.0()cos(
..
.


cirV
cUV
y
x


for horizontal flight, the flight path angle γ is zero.
Also
.
..75.0 c is the relative air effect of the
pitching rate
.
 which is manifested at 75% of the
chord length[13].
6
1
77.4 mU 

Fig.3.3.2 Side View of Flapping Motion
Fig. 3.3.3 Relative Flow of Air[12]
Now we can find out relative velocity, relative angle
between the two velocity components ψ and the
effective AOA as under:-
22
yxrel VVV  , )(tan 1
y
x
V
V
 ,
 eff
The section lift coefficient due to circulation (Kutta-
Joukowski condition, flat plate) is given by
effcl kCC sin)(2
The section lift can thus be calculated by:-
drcCVdL clrelc ...
2
1 2
 
which is to be integrated for entire wingspan. where
c and dr are the chord length and width of the
element of wing under consideration. The apparent
mass effect (momentum transferred by accelerating
air to the wing) for the section, is perpendicular to
the wing, and acts at mid chord, and can be
calculated as
The drag force has two components, profile drag
dDp and induced drag dDi. These are calculated as
under:-
drcCVdD
drcCVdD
direli
dprelp
..
2
1
..
2
1
2
2




Total section drag is thus given by:-
ipd dDdDdD 
Now, we have resolve horizontal and vertical
component of the forces given by:-


cos.coscos).sin(cos.sin
cos.cos).cos(cos.cos
dncchor
nccver
dDdNdLdF
dNdLdF


adding all the vertical and horizontal components of
forces will give the lift and thrust of the ornithopter
for that instance of time for which the calculations
are being done.
3.4 Flapping Wing in a Spring Mass System
Fig. 3.4.1 Canonical flapping configuration
consistent with our model; a single linear actuator
drives both wings symmetrically through an
(assumed) linear transmission, as viewed normal to
the stroke plane.
drrU
c
dNnc )5.0cos(
4
.....2






Fig. 3.4.2 Equivalent LP linear model used in our
analysis.
The system of the actutor and transmission wing
system of a flapping vehicleis an equivalent to one
degree of freedom(DOF) lumped parameters(LP)
linear model, characterized by effective mass,
stiffness and damping coefficients. Fig. 3.4.1 shows
a simplified flapping configuration with a single
power actuator driving two wings, and the
equivalent translational LP model. We assume that
the wings flap symmetrically in a horizontal stroke
plane, with peak-to-peak flapping amplitude . The
wings are coupled to the drive actuator through a
linear, lossless transmission with transmission ratio
T, where the time-varying flapping angle φ(t ) and
actuator displacement x(t ) are related by φ =
Tx.[13].
PROTOTYPE DESIGN AND FABRICATION :
The focus is shifted to design the MAV as gone
through the literature to enhance the knowledge of
the motion of flapping wings and how they generate
lift. Previous projects involving flapping wing
MAVs has provided a foundation from which MAV
can be design.
The process of design and modelling begans with a
basic idea of fabricating a flapping wing vehicle
capable of takeoff and landing , hover and horizontal
flight to achieve with this project. While literature
survey it has been decided that to mimick a bird
would be diffcult and unreasonable, for these
animals move in a very complex manner. Through
more research it is found out that elliptical shape
wing are designed more in previous flapping wing
MAVs due to its simpler aerodynamic shape and
theorical calculations.
4.1 Basic Flapping Wing Theory
Flapping flight is more complicated than flight with
fixed wings but stil the basic concept of
aerodynamics of fixed wing can be applied. The thin
membrane of flexible material can be sticked on the
leading edge and root chord of the wing. The thin
membrane are used for the wing is non-woven fibre
and cellos plastic.
According to the Ornithopter Design Manual
(Chronister, 1996) and Micah OHalloran (1998),
membrane wings generate positive lift and thrust
during the downstroke. However, during upstroke,
the lift becomes negative although thrust is still
positive. The material of the membrane is flexible.
Hence during downstroke, as shown in Fig. 4.1, air
is displaced downward and backward, causing the
membrane to be pushed upward andforward. The
direction of this force will produce lift and thrust.
Although the front of the membrane is glued to the
leading edge, the trailing end is allowed to swivel
within the limits of the flexible material. This will
cause the trailing edge to always lag behind the
leading edge. As a result, the membrane will become
positively cambered.
From fixed wing aerodynamics, the camber shape
will provide some additional lift as well.
Fig. 4.1.1 Wing Membrane Downstroke
During the upstroke, as shown in Fig. 4.2, the
reserve happens and the trailing edge is always
lower than the leading edge. The new direction of
force will provide thrust but negative lift.
Fig. 4.1.2 Wing Membrane Upstroke
Throughout the whole flapping cycle, the net force
will only be the thrust because the positive and
negative lift cancel each other out. In order to obtain
lift, the forces must be redirected by increasing the
pitch of the wing. In ornithopter’s design, this is
usually achieved using the tail. The tail is tilted
slightly upwards and this will cause the wing to
pitch up during flight (Fig. 4.1.3).

Fig. 4.1.3 Pitching of ornithopter to achieve net lift
4.2 Wing Design
One of important process of this project is wing
design and its development. The wing has semi-span
of 20cm having an half elliptical shape. The wing
has root chord of 18cm. The wing has an area of 565
sq.cm. The aspect ratio of wing is 2.22. The leading
edge and root of wing structure is been fabricated by
using balsa wood of 3mm thickness. Non-woven
fabric is using for wing membrane.
Fig. 4.2.1: Dimensions of Wing
Fig. 4.2.2: Wing Geometry
Fig. 4.2.3 Wing Layout
4.3 AIRFRAME
Airframe of the MAV has a length of 38cm. It is
made by fiber plastic. On the airframe, the gear
mechanism is mounted.
Fig. 4.3.1 Airframe Dimension
Fig 4.3.2 Airframe Structure

4.4 Flapping Mechanism
The main objective of flapping mechanism is to
convert the motor's rotary motion into flapping
motion. It is the most important component of the
MAV thus much research was done to assess the
many different designs available. Generally the
mechanism design is about the same to each other
with only slight modifications.
Types of Mechanism
Staggered Crank Design
The staggered crank design in Fig. 4.4.1 is the most
basic of the flapping wing design. The connector
rods are staggered in a measured distance and angle
to ensure that the left and right wing are flapping
symmetrically. This design is favoured by hobbyist
who wants to attempt to make their own Ornithopter
using household items. Modifications has to be made
so that the motor can be used instead of a rubber
band as its power source.
Fig. 4.4.1 Staggered Crank
Single Gear Crank
The single gear crank design in Fig. 4.4.2 taken from
University of California Biomimetic Millisystems
Lab, looks simple however it is more complicated
than it seems. Fig. 4.4.2 shows the wings at the same
level. The centre point where the connector rod and
the wing hinges are connected to each other has to
expand and contract as the mechanism flaps.
Contracting and expanding at a very high frequency
could result in component failure.
Fig. 4.4.2 Single Gear Crank
Dual Gear Crank Design
Fig. 4.4.3, taken from a published paper, shows the
dual gear crank design from similarly used in the
Festo'sSmartBird [10]. It features 2 gears that
controls each wing hinges separately. There are
different variation to the drivetrain design. The one
shown in Fig.4.4.3, uses the pinion wheel to drive
both the secondary gears. The secondary gears will
rotate in the same direction with each other. The
other design, has the pinion gear rotate the
secondary gear and this secondary gear to another
secondary gear. The secondary gears would rotate
counter clockwise to each other. This design is much
simpler to implement and reduce the wing symmetry
misalignment.
Fig. 4.4.3 Dual Gear Crank
Equation of Motion for Mechanism
Muller, gave few mechanism along with the
equation of the motion of the each of the
mechanism:
a) Direct Mechanism
Fig. 4.4.4 shows the direct mechanism in which the
wing is directly attached the motor. In this
mechanism, alternating the input signal does the
flapping of wing . The frequency and amplitude the
input signal does the flapping of the wings. The
flapping and amplitude are not predefined and can
be adjusted in this type of mechanism.
Fig.4.4.4 Direct Actuation
The equation of the motion is given as:
lFM dmw .
..


where, w is the moment of inertia of the wing
mM is motor torque
dF is aerodynamic drag force and
l is the characteristic length of the wing
b) Actuation with Mechanism
The mechanism is consists of four-bar linkage. The
amplitude is adjusted with length of the links and is
predefined as shown in Fig. 4.4.5. This design
doesn't need an alternating input signal.
Fig. 4.4.5: Actuation with Mechanism
The equation of the motor angle is:
FbMmm .)cos(
..
 
Where F is the force in the joint c
The equation of motion for the wing angle is:
FalFdw ).cos(.
..
 
The equation of motion for the four - bar mechanism
is given therefore as:
]))(sin.[.)
)sin(cos
cos
((.
)sincos(
)cos()cos(
1 2.
0
..






 owdm
o
ow
m
lF
a
b
M
a
c



c) Mechanism combined with torsional spring
This mechanism is same as mechanism in shown in
section b with a minor difference that there is a
torsional spring in the wing shown in Fig. 4.4.6. The
advantage of this system is that the amplitude of the
wing is amplified much more than the amplitude of
the bar-mechanism.
Fig. 4.4.6 Combined With Torsional Spring
The equation of the motion for the wing angle is
given as follows:
lFk dw .)(
..
 
The equation of motion for four-bar linkage is given
as:
))sin((.)
)sincos(
cos
(
..



 

 omm k
a
b
M
MAV's Gear Mechanism
Gear mechanism for MAV considered is dual crank
mechanism which slightly modified due to place
constraint in the airframe.
(a)

(b)
(c)
Fig.4.4.7 Gear Mechanism of MAV
In this mechanism the driving gear is attached to the
motor having a maximum speed of 6000rpm and
runs at the 1326kv. Then the driven gear is
connected to the one driven gear which mounted on
the 6mm diameter shaft along with it another gear is
mounted on shaft. Both the gear are installed with a
cranking shaft at a offset distance of 25mm from
center. On the crank shafts two control rods of
length 50mm are linked. The control rod length is
determine by practically by figuring out length
covered by the cranks from bottom to top or vice
verse. As the cranks are placed at the distance 25mm
from center then from top to bottom stroke length
will be 50mm.
RESULTS :
APPENDICES A: LIFT CALCULATIONS
Table A:1 shows the notation in the Table A:2.
B Semi span
βmax Maximum flapping angle
 Pitching angle
r(i) Distance along the span of the wing element i
Vx Horizontal velocity
Vy Vertical velocity
Vrel Relative velocity
 Relative angle
eff Effective AOA
Cl-c Lift coefficient due to circulation
C(k) Theodorsen Lift Deficiency
k Reducing frequency
C1 and C2 Constant
AR Aspect Ratio
dr Width of element
dLc Lift in element of width dr
Re ref. Reference Reynolds number
e Efficiency factor
Cf Skin friction coefficient
CDp Drag coefficient
Cdi Induced drag coefficient
dNnc Normal force
dFver Vertical components of force

Table A:2 below shows the data to calculate the lift distribution of flapping wing along the wing span of 40cm.
Flapping Rate Calculation Pitching Angle Calculation
βmax 30 B 27
t 2
.
 4
 12.5714286
Freq.  (t)
.
 (t) r(i)  (t)
.
 (t)
3 29.9982217 -0.2053155 0 0 0
3.05 24.0738299 -11.439679 2 -0.35721 -6.90139
3.1 8.94891702 -18.598589 4 -0.78956 5.01887
3.15 -9.5960873 -18.759739 6 -0.84444 33.75888
3.2 -24.473665 -11.633095 8 -0.24242 63.61543
3.25 -29.997913 0.2409597 10 0.917175 72.60709
3.3 -24.057577 12.392456 12 2.144212 44.72177
3.35 -8.9229322 20.104166 14 2.763063 -19.0882
3.4 9.62187367 20.242397 16 2.249784 -97.2557
3.45 24.4893979 12.525873 18 0.542205 -154.339
3.5 29.9975796 -0.2794552 20 -1.83757 -156.311
3.55 24.0413052 -13.347509 22 -3.93285 -88.0421
3.6 8.89694005 -21.610575 24 -4.73597 35.35916
3.65 -9.6476521 -21.724122 26 -3.65254 169.8133
3.7 -24.505111 -13.416313 28 -0.83841 257.5149
3.75 -29.997221 0.3208019 30 2.761195 251.0965
3.8 -24.025013 14.304836 32 5.723105 136.8316
3.85 -8.8709406 23.117812 34 6.708288 -53.8654
3.9 9.67342253 23.204913 36 5.052714 -251.455
3.95 24.5208031 14.304413 38 1.131019 -373.149
4 29.9968387 -0.3649997 40 -3.68804 -356.947
4.05 24.0087014 -15.264436 42 -7.51498 -191.06
4.1 8.84493378 -24.625872 44 -8.68 74.64053
4.15 -9.699185 -24.684766 46 -6.4503 342.206
4.2 -24.536475 -15.190171 48 -1.42004 501.2469
4.25 -29.996431 0.4120486 50 4.618096 473.8464
4.3 -23.99237 16.226305 52 9.308478 250.6955
4.35 -8.8189197 26.134754 54 10.65111 -97.7184
4.4 9.72493953 26.163676 56 7.845284 -442.089
4.45 24.5521275 16.073583 58 1.705473 -641.812
4.5 29.995999 -0.4619484 60 -5.55137 -601.779
Aerodynamics Calculation
U(m/s) 4
 6
c 13
Vx1 Vy1 Vrel
 .eff
3.840681 -0.27942 3.850832 -1 -1
34.60798 -22.032 41.02585 -0.91715 -1.27436
-41.5956 -109.906 117.5137 0.361374 -0.42819
-317.946 -435.521 539.2296 0.623087 -0.22136

-190.861 563.6379 595.0762 -0.32625 -0.56866
738.7738 107.0915 746.4954 0.999998 1.917173
482.8411 136.3703 501.7294 0.99832 3.142532
-86.0996 409.6362 418.5869 -0.20714 2.555919
-961.146 1247.213 1574.593 -0.6473 1.602485
-1011.6 -1384.66 1714.822 0.623421 1.165625
1926.308 -230.87 1940.094 -1 -2.83757
-794.547 -260.756 836.2402 0.995498 -2.93735
454.5446 -746.174 873.7198 -0.54354 -5.27951
1062.596 -2165.86 2412.484 -0.4547 -4.10724
-2437.56 2336.056 3376.22 -0.77925 -1.61765
1192.517 369.1771 1248.354 0.996877 3.758072
-922.987 391.1836 1002.461 -0.98231 4.740797
-279.399 1114.906 1149.382 -0.24549 6.462803
3026.018 3185.7 4393.799 0.739727 5.79244
-4301.11 -3423.21 5497.081 0.850083 1.981102
-2361.13 -524.031 2418.588 0.999756 -2.68828
2301.214 -528.117 2361.037 -0.99967 -8.51466
-641.205 -1515.51 1645.57 0.399536 -8.28047
-721.894 -4304.97 4365.079 0.166134 -6.28416
-6314.57 4646.851 7840.092 -0.87614 -2.29618
-6010.86 692.9622 6050.675 -1 3.618096
374.7405 667.5459 765.5377 0.508994 9.817472
1176.563 1942.986 2271.452 0.540982 11.1921
-5632.58 5517.021 7884.381 -0.77025 7.075033
-8105.17 -6011.97 10091.46 0.873621 2.579093
-5123.21 -877.958 5197.891 0.999983 -4.55139
Theodorsen lift Deficiency Factor Lift Calculation
AR 2.3 dr 1
K=f
C1 0.248918 C2 0.5166522
F G C(k) Cl_c c dLc
0.766741 -0.03965 0.7677659 -4.060903 0 0
0.766528 -0.03904 0.7675214 -4.613995 1 -0.00476
0.766325 -0.03844 0.7672882 -2.002608 2 -0.03388
0.76613 -0.03786 0.7670656 -1.058584 3 -0.56559
0.765945 -0.0373 0.7668529 -2.595718 4 -2.252
0.765768 -0.03676 0.7666496 4.5327389 5 7.735547
0.765599 -0.03623 0.7664551 -0.004524 6 -0.00418
0.765436 -0.03571 0.7662689 2.6623981 7 2.000085

0.765281 -0.03521 0.7660906 4.8130093 8 58.47219
0.765132 -0.03472 0.7659198 4.4245592 9 71.72272
0.76499 -0.03424 0.765756 -1.440903 10 -33.219
0.764853 -0.03378 0.7655988 -0.976074 11 -4.59879
0.764722 -0.03333 0.7654479 4.0581604 12 22.76989
0.764596 -0.03289 0.765303 3.9562263 13 183.3409
0.764475 -0.03246 0.7651638 -4.804322 14 -469.6
0.764358 -0.03205 0.76503 -2.780262 15 -39.8069
0.764247 -0.03164 0.7649012 -4.806011 16 -47.3311
0.764139 -0.03124 0.7647773 0.8588168 17 11.81366
0.764035 -0.03086 0.764658 -2.265186 18 -482.129
0.763935 -0.03048 0.7645431 4.4068217 19 1549.707
0.763839 -0.03011 0.7644323 -2.104329 20 -150.79
0.763746 -0.02975 0.7643256 -3.793399 21 -271.994
0.763657 -0.0294 0.7642226 -4.373396 22 -159.581
0.763571 -0.02906 0.7641232 -0.004689 23 -1.25852
0.763487 -0.02872 0.7640273 -3.593424 24 -3246.89
0.763407 -0.02839 0.7639347 -2.202498 25 -1234.72
0.763329 -0.02807 0.7638452 -1.837359 26 -17.1477
0.763254 -0.02776 0.7637587 -4.708362 27 -401.742
0.763182 -0.02745 0.7636751 3.4161055 28 3641.922
0.763111 -0.02715 0.7635942 2.5597088 29 4630.23
0.763044 -0.02686 0.763516 4.7371757 30 2351.805
Drag Calculation
Re ref. 105
dr 1
e 0.8
K 4.4
Cf 0.006999
CDp 0.030794
C Cdi dDi dDp dDdrag
0 2.851693 0 0 0
1 3.68139 0.003795 3.17E-05 0.003827
2 0.693505 0.011732 0.000521 0.012253
3 0.19378 0.103534 0.016453 0.119987
4 1.165125 1.010843 0.026716 1.037559
5 3.552867 6.063303 0.052553 6.115856
6 3.54E-06 3.27E-06 0.028488 0.028491
7 1.225755 0.920829 0.023134 0.943962
8 4.005815 48.66577 0.37411 49.03988

9 3.385303 54.87623 0.499175 55.37541
10 0.359027 8.277109 0.709934 8.987043
11 0.164749 0.776219 0.145086 0.921305
12 2.847842 15.97893 0.172782 16.15171
13 2.706573 125.429 1.427067 126.8561
14 3.991368 390.1372 3.009967 393.1472
15 1.336684 19.13822 0.440899 19.57912
16 3.994174 39.33584 0.303269 39.63911
17 0.127544 1.754457 0.423594 2.178051
18 0.887289 188.8531 6.554283 195.4074
19 3.358215 1180.953 10.82904 1191.782
20 0.765746 54.87123 2.206611 57.07784
21 2.488367 178.4207 2.207989 180.6287
22 3.307463 120.6858 1.123641 121.8095
23 3.8E-06 0.00102 8.265787 8.266808
24 2.232927 2017.596 27.82439 2045.42
25 0.838858 470.2647 17.26314 487.5278
26 0.583775 5.448261 0.287395 5.735656
27 3.833515 327.0953 2.627503 329.7228
28 2.017995 2151.391 32.82959 2184.221
29 1.133023 2049.513 55.70294 2105.216
30 3.880579 1926.541 15.2879 1941.829
Normal Force Vertical Force
U(m/s) 4 dFver
p 0.000163 -0.10877
-0.28958
0.151537
..
 (t)
..
 (t) dNnc -0.72475
0 10667.12 1.136517 -1.49895
-175.051 8848.184 0.932953 4.141026
-399.723 3397.842 0.32617 0.305786
-441.407 -3762.05 -0.45881 1.72753
-130.77 -9901.67 -1.1071 45.18228
510.3484 -12518.9 -1.33956 55.23078
1230.109 -10351.2 -1.03176 -17.3814
1633.535 -3956.46 -0.27596 -2.72668
1370.082 4394.675 0.643298 18.81993
339.9771 11516.63 1.355364 157.6248
-1185.85 14518.83 1.552161 -319.959
-2611.03 11970.82 1.120023 -20.5829
-3233.42 4555.698 0.198804 -24.8922

-2563.47 -5078.28 -0.8607 10.95422
-604.653 -13254.7 -1.62938 -341.264
2045.539 -16666.8 -1.77275 980.9589
4353.584 -13706.9 -1.19479 -78.4467
5238.189 -5195.18 -0.09148 -141.518
4048.572 5813.245 1.113273 -141.183
929.6338 15116.04 1.929581 -2.03951
-3108.59 18962.9 1.999761 -1994.46
-6493.61 15559.23 1.253083 -640.341
-7686.62 5874.509 -0.04923 -14.0393
-5852.26 -6599.95 -1.40326 -330.541
-1319.62 -17100.9 -2.25636 2510.864
4394.291 -21407 -2.2316 2853.084
9067 -17527.5 -1.29194 1219.874
10617.48 -6593.31 0.226561 Lift 122.1587
8001.328 7438.777 1.732906 Lift(N) 1.2215
1779.151 19209.6 2.610129
-5922.07 23999.25 2.466685
Fig. A.1 Lift distribution curve for flapping wing along span of 40cm
Fig.A.2 Drag distribution curve for flapping wing along span of 40cm.
-3000
-2000
-1000
0
1000
2000
3000
4000
0 10 20 30 40
Lift Distribution
Lift Distribution
-500
0
500
1000
1500
2000
2500
0 10 20 30 40
Cdi
dDi
dDp
dDdrag
Drag Distribution

CONCLUSION:
The goal of this thesis was to develop a MAV
capable of hovering flight. The focus was also in
the improvement in wing design and
controllability.These goals were fully reached. The
chosen mechanism for turning rotation of the DC-
motors into a flapping movement of the wings is
accurate and leads to error free functioning.
Through more than 300 tests the wings were
optimized in angle and chord length that yield to
enough lift generation for hover flight. In order to
achieve more lift generation the search space for
finding the optimal wing and mechanical
configuration can be extended by a smoother
discretization and including also the wing shape.
There were no improvements on the motors so far.
Many suppliers have the same size of DC-Motors
but with different parameters, such as velocity
constant. Also there should be a betterment in the
controllability by calibrating the motors and
reducing play in the structure.The gained
knowledge can be used for further improvements
and opens the way toward an autonomous flapping
wing MAV.In addition more improvements can be
done in the MAV such as adding a torsional spring
and improving the mechanical structure.In addition
there can also be the installation of a
microcontroller to increase its function capability.
REFERENCES
[1] Alexender, R. M., The U J and L of bird
flight , Nature(London), 1997.
[2] DeLaurier, J. D., An Aerodynamics Model
for Flapping Wing Filght. The
Aeronautical Journal of the Royal
Aeronautical Society April 1993, pp.125-
130.
[3] Mueller, T.J., Kellog, J.C., Ifju, P.G.,
Shkarayev, S.V., Introduction to the Design
of Fixed- Wing Micro Air Vehicles, AIAA
Education Series, AIAA, Reston, Virginia,
2007.
[4] Liu, C., Foundations of MEMS, Pearson
Prentice Hall, Upper Saddle River, New
Jersey, 2006.
[5] Freethy, Ron., How birds work: a guide to
bird biology. Blandford Press. 1982.
[6] Simkiss, K., Bird Flight. Hutchinson
Educational Ltd., London. 1963.
[7] Pennycuick. C. J., Predicting Wingbeat
frequency and wavelength of birds,
1989,J.exp biol.150,171-175.
[8] Hui hu, AnandGopakumar, Greg Abate,
Roberto Albertani, An experimental
investigation on the aerodynamics of
flexible membrane in flapping flight, 2009,
Aerospace Science and Technology
14(2010) 575-586.
[9] Mcmasters, J. H. and Henderson, M. L.
1980. Low Speed Single Element Airfoil
Synthesis. Tec. Soaring;2:1-21.
[10] Tay. W. B., Dynamics and Control of a
Flapping Wing Aircraft, M.E. Thesis,
National University of Singapore, 2003.
[11] Shyy, W., Lian, Y., Tang, J., Viieru, D.,
Liu, H., “Aerodynamics of Low Reynolds
Number Flyers.” ,Cambridge University
Press, New York, NY, 2008.
[12] Norberg, U.M., “Vertebrate Flight”,
Springer-Verlag,Berlin, 1990, pp. 166-179.
[13] Whitney. J. P and Wood. R. D., Conceptual
design of flapping wing micro air
vehicle,2011.
[14] Muller, T. J., Fixed and Flapping Wing
Aerodynamics for Micro Air Vehicle
Applications. Reston, VA: AIAA, 2001.

Design, Fabrication and Testing Of Flapping Wing Micro Air Vehicle

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