Umesh Kumar Meher

Multi functional, militarily capable, small flight vehicles.

size should be less than15cms. Reynold’s no < 10^5. For a Primarily intended and developed for

defence applications.

Keeps security personnel out of harms by providing situational awareness right down to platoon level.

Direct connectivity Can be individually controlled Can be used for a wide range of new

missions _ (even unthought before)

Reconnaissance Surveillance Defence

applications Weather forecast Wildlife study

&photography Crowd control

Targetting Border surveillance Traffic monitoring Tracking criminals

& illegal activities Biochemical

sensing Sesmic detection inspection of pipes

1. FLIGHT CONTROL

2. PROPULSION SYSTEM

3. COMMUNICATION SYSTEM

4. GUIDANCE&NAVIGATION

Completely different aerodynamics due to low Reynold’s number

Reynold’s no:= inertia force/viscous force Here viscous forces dominate while at high

Reynold’s no:’s inertia forces dominate Reynold’s no:=c/ Low reynold’s no: flights may have lift to

drag ratioof 5 to 10(conventional flights have these ratios 3 to 4 times higher)

Due to small size it needs to have high surface to volume ratios to generate the required thrust

Aspect ratio=WS/chord length ,or WS²/total wing area

Exact ratio depends upon the total weight The best aspect ratios usually lie between

1&2 Stability and control issues related to low

weight ,small moment of inertia ,wind gusts also needs to be addressed

                                                                                            

                                                          

Angle of attack shoud be 5-12° for good endurance.

If angle of attack <5, low aerodynamic efficiency

Endurance=/powerequirement For optimal endurance the mav shoud fly

at7° Hysterisis may occur (lift to drag ratio

different from normalwhen angle of attack differs)

Use strategies using MEMS to improve aero dynamic perfomance Create &install tiny sensors to dynamically adjust camber(curvature)and shape depending on instantaneous conditions miniature actuators can be used to move the control surfaces like rudders ailerons and flaps Flow character over the wings could be controlled by sensor arrays that detect shear stresses or fluid vortices Flexible mebranes or micro flaps to affect the flow as required

Flow seperation an be mitigated by air sution or absorption as required,(requires micro valve or pump),wallheat transfer or electro magnetic force as required

Exhausted air is directed out of the trailing edge to prevent flow seperation,which also inreases lift

Micro motors piezoelectricdevices magneto elastic ribbons are all alternatives for performing the actuator function in a flight control system

Processing these control systems may require soft computational techniques like fuzzy logic,neutral networks,genetical algorithms or knowledge based systems

Rotary wings, fixed wings, or alternate flapping& gliding wings could be employed Wing shape could be circular, elliptical, rectangular, Zimmerman or inverse Zimmerman Flapping &gliding and inverse Zimmerman proved to be most efficient Wing type depends on requirement Composite materials ,carbon fibre cloth strips, carbon fibre-balsawood sand witches are commonly used Single or double layer of carbon fibre cloth wetted with epoxy resin Balsa wood for frame and carbon fibre glass cloth for reinforcing critical areas like leading edges and wing tips is a super combination

Distend (fill) with air or gas

Application in UAV, military

To stow the wings

Can be launched from gun or aircraft

Can be packed to 1/10 of original size Low mass Low power requirements High reusability It can be steered, accelerated, and

decelerated in level flight. High stability and control High lift and slow landing speed

Experiment conducted using I 2000

It was launched from 800-1000 feet

Inflatable wings comes out in 1\3 sec

Successfully controlled the launch,flight and landing

by using piezoelectric by using piezoelectric materialmaterial

actuator can be quartz and substrate can be aluminum or steel

inflatable wings has smooth surface so low value of skin friction

Propulsion system alone consumes 90% of total power

Lithium alkaline batteries IC engines Pulse jet engines Micro jets Reciprocating chemical muscle Self consuming system Lithium battery that recharges using solar

energy and fuel cells are also future prospects

A video/still camera, various sensors ,a micro processor, transducers& an omni directional antennae are the major components

Challenges are small antennae, restriction of power available

Based on the application either cellular communication or satellite communication could be employed.

CCD cameras and IR sensors, nuclear, biological or chemical agent sensors, acoustic sensors could be used.

Completely autonomous navigation system needs to have the ability to use sensory data for on board processing thus avoiding obstacles. (complete dependence on remote is undesirable)

A combination of GPS+inertial sensing is ideal Geographical information system to provide a

map terrain for infrastructure would be great Pressure sensors acting as altimeters,

accelerometers, low drift gyroscopes and also systems capable of locating the mav ’s position with respect to the launch point form a part of the inertial navigation system

Micro Air Vehicles are a class of UAVs whose time has just about come. A confluence of key events is about to occur that will enable these versatile aircraft to have military effects disproportionate to their diminutive size. The supporting technologies are progressing rapidly to the point that first simple, short-duration missions will be possible, then with time, more varied and enduring applications. At the same time, the need for weapons that help achieve the Joint Chief of Staff vision for dominant maneuvering precision engagement, full dimensional protection, and focused logistics will be more pressing than ever. The military utility of MAVs in this context can only grow as they come closer to realizing their potential. At the start, microairvehicles could find application by providing localized imaging reconnaissance. Then as other key technologies mature, uses may expand to electronic warfare, nuclear, biological, and chemical agent warning, and battle damage assessment. Later still, we could see MAVs autonomously flying through air shafts reconnoitering deeply buried bunkers and reporting back to enable proper configuration of penetrating weapons. MAVs might then proliferate throughout the force structure becoming as much an —arrow in the quiver“ of the foot soldier as another round on the hardpoint of a fighter‘s wing.

Research paper “Death by a thousand cuts”micro air vehicles in the service of air force missions- by ARTHUR F HUBER,II LT COL USAF

http://mil.ufl.edu/~nechyba 2. Davis, W.R., "Micro UAV," Presentation to 23rd Annual AUVSI Symposium, 15-19

July, 1996.

Research paper by James M. McMichael Program Manager Defense Advanced Research Projects Agency

and Col. Michael S. Francis, USAF (Ret.) formerly of Defense Airborne

Reconnaissance Office MICRO AERIAL VEHICLE DEVELOPMENT: DESIGN, COMPONENTS,

FABRICATION, AND FLIGHT-TESTING Research paper by Gabriel Torres and Thomas J. Mueller

117 Hessert Center, University of Notre Dame Notre Dame, IN 46556 DESIGN AND DEVELOPMENT OF A MICRO AIR VEHICLE CONCEPT: PROJECT BIDULE Mr T. Spoerry1, Dr K.C. Wong School of Aerospace, Mechanical and Mechatronic Engineering University of Sydney NSW 2006

Aerodynamics for engineers:-John J. Bertin Mechanics of flight :-A.C Kermode Inflatable wing on aircraft article :-new scientist june 2001 www. nasa explores. COM\aerodynamics\inflatable wing Miller, Jay,, The X-Planes, Aero fax, Arlington, Texas, 1988 morphing of inflatable wing for UAV David Cardigan* and

Tim Smith† ILC Dover, Frederica, DE 19946 Innovative Wing Design Could Soar in Martian Skies

by benianntova Inflatable wing for high lift john H gleen research centre Ohio www.nastech.com/mechtech www.spaceref.com/newtech www.nasa.gov/aerodynamics www.nasa.gov/multimeadia

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