Morphing aircraft are multi-role aircraft that change their external shape substantially to adapt to a changing mission environment during flight. Morphing poses several unique challenges when the wing loading is high. Very flexible materials are the designer’s first choice because they are easily reshaped. he current use of multiple aerodynamic devices (such as flaps and slats) represents a simplification of the general idea behind morphing. Traditional control systems (with fixed geometry and/or location) give high aerodynamic performance over a fixed range and for a limited set of flight conditions.

1. Design of Aircraft and Unmanned Aerial Vehicles
Name: Naga manikanta Kommanaboina
Master Science – Aeronautical Engineering
Kaunas University of Technology

2. Table of Contents
Introduction…………………………………………………………………..3
Benefits ………………………………………………………………………3
Morphing aircraft design features…………………………………………..3
The DARPA Morphing Aircraft Structures Program……………………..3
The MAS program had two primary technical goals………………………4
Morphing Aircraft Structures Design……………………………………….4
Morphing wing concept………………………………………………………4
1.Wing planform alternation………………………………………………………5
(a)Wing span resizing………………………………………………………………………………5
(b)Chord length change……………………………………………………………………………..5
(c)Sweep angle variation……………………………………………………………………………6
2.Out-of-plane transformation of the wing……………………………………….7
(a)Airfoil camber changing………………………………………………………..7
(i)Camber change by using internal mechanism………………………………………………… 7
(ii)Piezoelectric actuation for camber change……………………………………………………...7
(iii)Shape memory alloy actuation for camber change…………………………………………….7
3.Airfoil profile adjustment………………………………………………………..8
Morphing Skins……………………………………………………………….8
Lateral wing bending…………………………………………………………8
Wing twisting………………………………………………………………….9
Developments in wing morphing by authors………………………………..9
Changing Wing Area – Materials &
Actuators Selection & Mechanism Design…………………………………10
Conclusion…………………………………………………………………….10
References……………………………………………………………………..11
Image References……………………………………………………………..12

3. Morphing Aircraft Technology – New Shapes for Aircraft Wing Design
Introduction:
Morphing aircraft are multi-role aircraft that change their external shape substantially to adapt to a
changing mission environment during flight.
Morphing poses several unique challenges when the wing loading is high. Very flexible materials are the
designer’s first choice because they are easily reshaped
In the field of aeronautics, “shape morphing” has been used to identify those aircraft that undergo certain
geometrical changes to enhance or adapt to their mission profiles.
There is neither an exact definition nor an agreement between the researchers about the type or the extent
of the geometrical changes necessary to qualify an aircraft for the title “shape morphing”. There is not a
clear definition for an enabling “shape morphing” technology either.
However, there is a general agreement that the conventional hinged control surfaces or high lift devices,
such as flaps or slats that provide discrete geometry changes cannot be considered as “morphing
Benefits of Morphing
The current use of multiple aerodynamic devices (such as flaps and slats) represents a simplification of
the general idea behind morphing. Traditional control systems (with fixed geometry and/or location) give
high aerodynamic performance over a fixed range and for a limited set of flight conditions. Outside of this
range, these traditional systems can be neutral or negatively influence the aerodynamics and hence often
give lower efficiency. Conventional hinged mechanisms are effective in controlling the airflow, but they
are not efficient, as the hinges and other junctions usually create discontinuities in the surface, resulting
in unwanted fluid dynamic phenomena. Since 1920, airplanes have used devices that can increase the lift
during landing and takeoff (Ranken, 1985). Increases in aircraft weight and cruise speed and increases in
the wing structural stiffness to avoid multiple aero-elastic phenomena (divergence, flutter, etc.) have led
to the use of discrete control surfaces such as ailerons and flaps in place of wing twist. Only since the late
1970s have researchers seriously revisited concepts of variable wing shape. Most of this research was
based on two concepts, namely the active control of the curvature along the wingspan and the
implementation of flexible wings, able to exploit the aero-elastic forces to obtain the desired deformations
(wing shapes). Many studies have targeted the variation of the wing shape (Weiss, 2003; Sofla et al., 2010)
to achieve several objectives, such as the control of shock waves during transonic flight conditions, or the
control of turbulence, the wake (laminar flow separation), vortices, active control of flutter, etc.
(Stanewsky, 2001).
Morphing Aircraft Design Features:
Morphing aircraft design features reconcile conflicting mission requirements so that an aircraft can
perform several mission functions or roles.
These functions could be as simple as being able to use a small engine but land and take off from a short
length field.
These conflicting requirements make landing flaps appear on wings to increase area and lift coefficient at
low speed, despite the increased weight that they add to the system.
morphing devices are not added then the wing design is compromised so that the aircraft may do one thing
very well, but have problems executing other parts of the mission.
The Defense Advanced Research Projects Agency (DARPA)Morphing Aircraft
Structures Program:
These Morphing Aircraft Structures, developed under a DARPA program, are scheduled for testing in
early 2005. Morphing capability applied to a missile would enable efficient flight at multiple speeds and
altitudes without sacrificing performance as is currently the case when operating off the optimized cruise
point. Morphing wings is the first in a series of steps to permit a cruise missile to travel at high speeds to

4. a target area, loiter and then move to another target area, with speed changes from 0.3 Mach to 3.0 Mach.
The technology ultimately could be applied to other platforms and future air vehicles, manned and
unmanned. To facilitate such morphing structures, the integrated system design probes advanced
materials, actuators, sensors and electronics to create devices and adaptive structures that enable
significant in-flight vehicle shape change. These shape changes are more significant than those currently
found in flight vehicles, and, in turn, will enable new military capabilities such as those envisioned by
Raytheon.
It is one thing to draw a morphing wing design or to calculate shape changing wing performance. It is
quite another to conceive, design, build and operate shape changing designs, particularly when the
geometrical shape changes are large.
The MAS Program had Two Primary Technical goals:
1) To develop active wing structures that change shape to provide a wide range of aerodynamic
performance and flight control not possible with conventional wings.
2) To enable development of air vehicle systems with fleet operational effectiveness not possible with
conventional aircraft. This includes both Navy and Air Force operations.
Morphing Aircraft Structures Design:
The MAS missions considered by the three contractors were structured to provide general system
performance for:
1. Responsiveness – time critical deployment with the ability to respond to unpredictable crisis situations
•
2. Agility – the ability to attack fast moving air and ground targets.
3. Persistence – the ability to dominate large operational areas for long time periods
Morphing Wing Concept:
Morphing aircraft are flight vehicles that changes their shape to effect both a change in the mission of the
aircraft and to perform flight control without the use of conventional control surfaces or seams.
Aircraft constructed with morphing technology then it will able to fly multiple types of missions, to
perform radically new maneuver not possible with conventional control surfaces, to be more fuel efficient,
and to provide a reduced radar signature.
The key to morphing aircraft is the full integration of the shape to control in to the wing structure.
The wing morphing concepts can be classified into three major types
1.Plan form alternation,
2.out-of-plane transformation
3.airfoil adjustment

5. Fig 1. Morphing wing [Ref 1]
Fig 2. Classification of Shape Morphing Wing [Ref 2]
1.Wing planform alternation:
The wing planform can be reconfigured by the resizing of span and chord length, and by changing the
sweep angle
(a)Wing span resizing:
Telescopic structures have been extensively used for dramatic length change of the wing structure. The
morphing wing in the telescopic designs is sectioned longitudinally to form several segments with
reducing cross sectional
(b)Chord length change:
The chord length of the wing in conventional aircraft is resized by means of leading/trailing edge flaps,
which are usually moved by lead and screw actuation systems. Many of these devices are patented and
operational.

6. Fig 3. Wing Planforms [Ref 3]
(c) Sweep angle variation:
Pivoting of the wing so far has been the method of choice for the sweep change, or even for the shape
morphing, implemented in many successful and operational aircraft such as: Bell-X-5, F-111, F-14, and
B-1. All of the aerodynamic loads on the wing in those designs are supported by a pivoting mechanism.
Such a pivot is complex to build and install. It is heavy and needs elaborate maintenance
Fig 4. wing planform Alternation [Ref 4]
2.Out-of-plane transformation of the wing:
Another way of changing the aerodynamic behavior of the wing is by recasting the wing out of its original
plane.

7. Three types of such rearrangements are demonstrated. Smart materials usage for the shape morphing of
wing has been extensively explored through this approach.
(a)Airfoil camber changing:
Changing the airfoil camber is the most investigated approach of shape morphing. The airfoil camber can
be uniformly changed along the span in a similar manner to the rotation of the ailerons.
Alternatively, gradual changes of the airfoil camber along the span can create controllable twisting of the
wing. The necessary camber change is pursued either by the reconfiguration of the underlying structure
(e.g. ribs) or the morphing of the wing skin.
Here the following classification is used for the airfoil camber change methods:
(i) using internal mechanisms,
(ii) piezoelectric actuation
(iii) shape memory alloy actuation.
Fig 5. Morphing Wing with Corrugated Morphing Skin [Ref 5]
(i)Camber change by using internal mechanism:
Breaking the rib structure to finger-like sequential hinged segments is probably the most trivial concept
for changing the wing camber with many patents registered. The work by Monner et al. is a good
representative of this segmented rib concept In their design the ribs consisted of separate plate-like
elements which are connected by revolute joints that can be driven from one single point. Flexible skin
covered the airfoil in their design. The top and bottom skins could slide with respect to each other at the
trailing edge to allow larger displacement of the trailing edge.
(II)Piezoelectric actuation for camber change:
The stacks were mounted locally between two reacting “vertebrae” which provided the necessary arm to
convert the linear extension of the stack into local moments.
(iii)Shape memory alloy actuation for camber change:
Shape memory alloy was also a candidate actuating material for the DARPA Smart Wing program. Two
SMA linear actuators were connected to tip of a flexible trailing edge in their concept. The other ends
were connected to the top and bottom of the trailing edge spar in an antagonistic way . The contraction of
the actuators could bend the trailing edge respectively. Wang reports that the gained deformations were
not satisfactory because the ability of the actuator to displace the trailing edge tip was reduced as a result
of wasting of the shape memory recovery force due to the undesired in-plane compression of the center
sheet.
3.Airfoil profile adjustment:
Several researchers have explored the ways to alter the aerodynamic properties of the wing by the
reshaping of the airfoil profile
e airfoil shape could therefore be modified by the expansion or contraction of the actuators. They
constructed a model of an adaptive rib with 14 mechanical ball-screw actuators to demonstrate their shape-
control concept

8. Fig 6. Airfoil profile adjustment [Ref 6]
Morphing Skin
Most of the morphing technologies or concepts assume the existence of an appropriate flexible skin. The
design of flexible skins is challenging and has many conflicting requirements. The skin must be soft
enough to allow shape changes but at the same time it must be stiff enough to withstand the aerodynamic
loads and maintain the required shape/profile. This requires thorough trade-off design studies between the
requirements. In addition, the type of flexible skin required depends on the loading scenario and the
desired change in shape (one-dimensional or multi-dimensional). Therefore, the design of flexible skins
depends on the specific application.
Fig 7. Corrugated morphing wing section with upper skin and bottom flexible sheet. [Ref 7]
Lateral Wing Bending:
The main problem associated with their design was that the SMA had to be kept heated in order to carry
aerodynamic loads. There is no detail about reversibility of their actuator, that whether it could return to
the original shape.

9. Fig 8. Lateral wing bending [Ref 8]
Wing Twisting:
wing consisted of an elastic wing box structure (ABS plastic material) which was covered with an
elastomeric skin. The wing box is rigidly coupled to four concentric tubes, which are independently
attached to the wing at four locations along the span. The outer tubes pass through the inner ones and are
connected to servomotors at the wing root. The wing could be twisted by the arbitrary rotation of the tubes.
It was shown that the angle of attack envelope of a twisted wing was increased. Stanford et al. also
controlled the roll of a mini UAV by twisting its flexible wing. In their design torque rods ran laterally
toward the end of each wing and were allowed to freely twist within metal sleeves glued to the wing at
the leading edge. Both left and right rods were connected to a single servomotor which was housed on the
bottom surface of the win
Fig 9. Wing Twisting [Ref 9]
Developments in wing morphing by authors:
The shape morphingUAV projectat the Mechanicsand Aerospace DesignLaboratory(MADL) atthe Universityof
Toronto was launched in April 2008 with the support of DSO National Laboratories in Singapore

10. The SMA-actuated flexural structures can carry aerodynamic loads and undergo large shape changes
Fig 10. Light weight SMA actuated truss beam lifts a load about six times of the beams weight to a
distance of half of the beam span. [Ref 10]
CHANGING WING AREA – MATERIALS & ACTUATOR SELECTION &
MECHANISM DESIGN:
First, many new, novel materials, material systems and actuation devices have been developed during the
past decade. These developments allow designers to distribute actuation forces and power optimally and
more efficiently. Properly used, these devices reduce, weight compared to other, more established
methods.
Finally, missions today differ markedly from those a decade ago. We face both sophisticated and
unsophisticated adversaries.
Wing shape-changing concepts require actuators attached to internal mechanisms, covered with
flexible/sliding aerodynamic surfaces - with load transfer attachments between skin and skeleton. This
requires a distributed array of actuators, mechanisms and materials that slide relative to each other or skin
materials that stretch. Mechanism design requirements include the range of motion and concerns about
binding and friction as well as the effects of wing structural deformability under load and the control of
the actuator stroke under loads.
Actuator performance power and actuator force capability are essential to design success. The size, weight
and volume of the actuators are an important metric, as is range of motion, bandwidth and fail-safe
behavior.
Morphing designs may also benefit from geometrically flexible structural designs if the aeroelastic energy
from the airstream can be used to activate the shape changing and tabs can use aeroelastic control
approaches for maintaining shape. The wealth of new technologies available to the wing designer provides
intriguing design possibilities
Conclusion
This paper has reviewed new Morphing Aircraft Technology and – New Shapes for Aircraft wing design.
In general, any successful wing morphing scenario must overcome the weight penalty due to the added
actuation systems
any successful conceptual design for shape morphing of low speed/small aircraft should:
Undergo large geometry changes and Use smart materials for actuation
Use advanced light-weight composites for the fixed structure and the skin.

11. References
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Available at: https://arc.aiaa.org/doi/abs/10.2514/6.2007-1258.
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SUPERIOR TÉCNICO Universidade Técnica de Lisboa , October 2017 [online ] Available at :
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USA, http://www.dtic.mil/get-tr-doc/pdf?AD=ADA479821.
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[online] Available at: :
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Image References
[1].Fig[1] Morphing wing [2015] [image] Available at:
http://rrvi.iut.ac.ir/images/ResearchTopics/CompositeStructures/BiStable/image1.jpeg
[2].Fig[2] Classification of Shape Morphing Wing [image ] Available at :
https://www.researchgate.net/profile/Noor_Iswadi_Ismail/publication/305472016/figure/fig1/A
S:386164713377792@1469080250281/Fig-1-A-classification-for-shape-morphing-of-wing-
Sofla-et-al-2010.ppm
[3].Fig[3] Wing Planforms [image] Available at :http://www.dauntless-
soft.com/products/freebies/library/books/flt/chapter17/wing%20planform_files/imagehk0.jpg
[4].Fig[4] wing planform Alternation [image] Available at: https://ars.els-
cdn.com/content/image/1-s2.0-S0261306909004968-gr2.jpg
[5]Fig[5] Morphing Wing with Corrugated Morphing Skin [image] Available at :
https://img.youtube.com/vi/MwMsGgsfsZ4/mqdefault.jpg

12. [6].Fig[6] Airfoil profile adjustment [image] Available at
http://ascelibrary.org/cms/attachment/5506/32359/figure1.gif
[7] .Fig[7] Corrugated morphing wing section with upper skin and bottom flexible sheet [image ]
Available at :http://journals.sagepub.com/doi/full/10.1177/1045389X16642298
[8]. Fig[8]. Lateral wing bending [image] Available at:https://ars.els-cdn.com/content/image/1-
s2.0-S0261306909004968-gr3.jpg
[9].Fig[9] Lateral wing bending image] Available at :https://ars.els-cdn.com/content/image/1-
s2.0-S0261306909004968-gr3.jpg
[10].Fig [10] Light weight SMA actuated truss beam lifts a load about six times of the beams
weight to a distance of half of the beam span [image]Available at: https://ars.els-
cdn.com/content/image/1-s2.0-S0261306909004968-gr7.jpg