15-03-2011, 09:09 PM
Morphing Aircraft Technology
&
New Shapes For Aircraft Design
V.Vikram
S6 Department of Mechanical Engineering
Mohandas college of Engineering and Technology
&
New Shapes For Aircraft Design
V.Vikram
S6 Department of Mechanical Engineering
Mohandas college of Engineering and Technology
Morphing Aircraft Technology and new techniques for aircraft design.pdf (Size: 236 KB / Downloads: 334)
Abstract
Morphing aircraft are multi-role aircraft that change their external shape substantially to adapt to a changing
mission environment during flight.2 This creates superior system capabilities not possible without morphing shape
changes. The objective of morphing activities is to develop high performance
aircraft with wings designed to change shape and performance substantially during flight to create multiple-regime,
aerodynamically-efficient, shape-changing aircraft.
Compared to conventional aircraft, morphing aircraft become more competitive as more mission tasks or roles are
added to their requirements. This paper will review the history of morphing aircraft, describe a recent DARPA
program, recently completed, and identify critical technologies required to enable morphing.
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. If 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.
Introduction
Even before the official beginning of controlled
human flight in 1903, radical shape changing aircraft
appeared and then disappeared, contributing little to
aviation. Clement Ader conducted flight experiments
in France as early as 1873 and proposed a wing
morphing design as early as 1890, as indicated in
Figure 6. He developed ideas for the future of
aviation for warfare beginning in the 1890’s and
described them in a short monograph published in
1909. He advocated three
basic types of aircraft as parts of future military air
fleets: Scouts, Bombers and Airplanes of the Line.
Consider his description of the general military
airplane and in particular, the Scout aircraft:
“Whatever category airplanes might belong to, they
must satisfy the following general conditions: their
wings must be articulated in all their parts and must
be able to fold up completely… When advances in
aircraft design and construction permit, the frames
will fold and the membranes will be elastic in order
to diminish or increase the bearing surfaces at the
wish of the pilot… The Scouts will be designed
according to their function…everything should be
sacrificed in the interest of speed and flying long
distances. Their wings will be bat-type or preferably
bird type, long and narrow, with the minimum of
surface and hence a heavy load for each square
meter. Moreover the wings will be adjustable, so
that in flight they can be reduced by a half or a
third or even less…Armament will be nonexistent or
very little…The real weapon will be speed.”
Morphed Designs
Makhonine’s telescoping wing had three major parts
that slid over each other to change the wing span and
area: in operation, this airplane changed wing span
162% (from 13 meters to 21 meters) while the wing
area changed 157% (from 21 to 33 square meters).
Pneumatic actuators provided the energy for
extension
and contraction. The wing loading was about 30
lb/square ft and the airplane was considered to be
underpowered, with a maximum speed of 186 mph
with the wings retracted and 155 mph with the wings
fully extended. Makhonine designed other successful
variable-geometry aircraft. His last, the MAK-123,
was first flown in 1947 in France and demonstrated
extension retraction of telescoping wings with no
adverse effects.
The variable sweep concept comes closest to the
present day morphing wing concepts as far as
objectives are concerned. The interest in variable
geometry wings in the 1950’s and 60’s arose because
of aerodynamically dissimilar mission objectives.
These objectives were:
• Long-range subsonic cruise or long0endurance on
station
• High supersonic speed interception and low-altitude
transonic strike
• Operation from limited length runways (or aircraft
carriers).
Morphing Materials
Synthetic Jets
• Synthetic jets covers a part of a wing.
• It replicates the effect of bird feathers.
• This makes the airplane more comfortable
and stable.
Microspheres
• Microspheres imitate the pores inside the
birds bones.
• Microspheres are injected in composite
materials and is heated to fuse them
together.
• It helps to achieve a light weight and strong
structure.
SMART MATERIALS
• Smart materials move according to
command.
• These materials responds to stimulus
like electricity, heat and magnetism.
• It regains it original shape.
Mas Program
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.
The MAS effort was an extension of activities that
began more than a decade ago with DARPA’s
development of smart materials and devices; this
effort was led by Dr. Robert Crowe, then a Program
Manager in the DARPA/Defense Sciences Office
(DSO). He followed this with demonstration projects
such as the Smart Wing Program, SAMPSON (an
advanced inlet morphing program), and the Smart
Rotor Program. The Compact Hybrid Actuator
Program (CHAP) was developed by Dr. Ephrahim
Garcia during his tenure as a DARPA Program
Manager.
Conclusion
The need of aircraft solutions
Morphing aircraft are distinguished by their ability to
change shape to respond to new environments that
are encountered as their missions unfold. It is fair to
ask “so what, how will that increase my military
capabilities?” The answer to that question requires
the questioner to accept several assumptions about
the future. The first assumption is that enemies of the
future will have a substantial, sophisticated air
defense composed of a variety of radar directed
weapons that can acquire and target airborne assets.
A second assumption is that the enemy of the future
will be adept at moving and hiding valuable assets,
making them harder to find and more difficult to
strike.
The answer to this problem is to develop systems that
can search, locate, target and attack both air and
ground targets, but can also survive and persist in the
face of a dedicated, high-tech enemy.
References
1. Aeronautics and Astronautics Department
Purdue University USA.
2. Official website of NASA