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Discussions on bio-mimicking MAVs intend to have a streamlined body for

reducing the drag and increasing the associated aerodynamic forces. However, the

power source is the battery and not the biological contractile oxidative muscles. It is

not possible to use flight muscles for the production of power as in real insects. The

flight muscles of insects, birds and bats are more sophisticated and more complicated

in their cellular structure, attachments and the functions. Although a number of exper-

iments have been carried out for the synthesis of artificial muscles, it has not been

possible to achieve control on their contraction and relaxation as it happens in biolog-

ical systems. There is a superior feedback control systems acting in milli-seconds,

regulated by neuronal mechanisms and structural characteristics.

Following are some of the specific and necessary aspects for different MAVs,

which share common characters between them:

1.

Weight Range—20 to 250 gm for the Bird-mimicking MAVs and 100 mg to

60 gm for Insect Mimicking MAVs.

2.

Size—The maximum size can be about 40 cm (400 mm)—that would represent

the wing span for bird model MAVs and 5–6 cm (50–60 mm) for insect model

MAVs.

3.

Aspect Ratio—Range 2–3.

4.

Wing design—Copying the membranous wing of insects is easier than to copy

the wings of birds and bats, which are highly complex in their structure. Insect

wings are made up of chitin, a polysaccharide amine thin membrane. These

wings can develop differential aerodynamic forces during up and down stroke

movements. The flapping of wings in biological insects and birds is possible

due to aeroelastic properties of different components of the flexible wings and

wing joints.

5.

Lift to Drag (L/D) Ratio—This is relatively low for such models.

6.

The maximumspeed attainedbythesefliershastoberestrictedto30–40km/hr

(approximately 8–10 m/s). There is quite a possibility that these light MAVs

might be carried away backward and lose their way if there is a gust wind,

flowing in the opposite direction.

7.

The suggested wingbeat frequency can be restricted to be in the range of 10–

20 cps, keeping in view the bio-acoustic sound levels, which are significant in

bio-mimicking designs.

8.

Inaninsectfliertheproximalareaofthewing,whichisattachedtothethoraxby

an elastic hinge is broader and thicker leading to a distal membranous area. The

proximal area develops required lift; the distal area helps in the contribution

of thrust and the wing tip in the development of induced drag due to vortices.

The shape of the wing may be chosen to be roughly rectangular or elliptical.

These aspects in general require careful study while selecting the wing shape

and structure for bio-mimicking MAVs.

9.

MAVs have a serious problem of landing and takeoff as compared to the natural

fliers. It may be possible to adopt the landing and takeoff system similar to the

Perching Mechanisms of natural fliers. This perching action is being practiced