Yanghai Nan paper represented geometric similarity and comprehensive scaling law in wing performance estimation through statistical analysis. His works show the ranges of the wing performance of the lumped mass parameter and the ratio of the flapping wing MAVs. His results provide a simple but powerful guideline for the design of flapping wing MAVs and the morphology of the natural flyers. The lumped parameter had comprehensively studied and observed the relationship between the lumped parameter and the aspect ratios, the lumped parameter is inversely proportional, and the lumped parameter is independent of the body mass through geometric similarity analysis.
Then they defined the Pw “AR ratio and estimate the wing performance and aerodynamic performance.Shiva Prasad Uppu work is to determine the aerodynamic properties of the dragonfly airfoils in comparison to the traditional smooth NACA 2.5411 airfoils. At low speed, simplified dragonfly airfoils are analyzed and a 3D printed model is tested using the Six Component Strain Gauge and compared the result with the NACA 2.
5411 airfoils. At Low Reynold’s number, Aerodynamic performance is evaluated with the regular section. Both the Experimental and numerical work was Carried out Over the models at different wind speed. His Result shows a completely nonlinear behavior resulting in positive Aerodynamic forces. With his work, they resulted that Dragonfly airfoils have better Aerodynamic characteristics like high Cl and Cl/Cd. due to Corrugated Cross-section, Dragonfly airfoils has more Cd when compared to NACA 2.5411 but in return, it offers more lift due to its vorticesgenerated at the valley in the cross section and more lift generated when operated at the AOA.Jae Hyung Jang paper proposed a wing root control mechanism inspired by the drag “based-system of the dragonfly to control the angle of the attack. They designed a spatial four-bar linked based flapping mechanism using a 3D printer. In the aerodynamic analysis, when the wing root angle of 0o with the increased angle of attack of 30o, the drag based system reduced the amplitude of the force in the horizontal direction to approximately 0.15N and 0.1N in the downstroke and upstroke respectively in compared with lift based system. The measured forced showed that MAV with wing rotation mechanism flies more stable when hovering and with changing the wing root angle, the flight mode can be changed easily.Structural Analysis of a Dragonfly Wing(S.R. Jongerius & D. Lentink ” 2010)S.R Jongerius  shows resonant frequency of the flapping wing is tuned for carrying the aerodynamic and inertial load but they are not fully understood. His paper presented his work on the structural analysis of the dragonfly wing. They create a 3D scan of a dragonfly with a micro CT-scanner, which contains complete venation patterns including thickness variation throughout, and approximated the forewing architecture with efficient 3D Beam and shell and then determined the wing deformation and wings natural variation modes. As a result, from his computation, because of the structural asymmetric, deformation is larger in upstroke than downstroke. Also, found that, at vacuum, the natural frequency of dragonfly is 154 Hz and in Hovering flight 32.3 Hz. Thus, these structural properties and his aero elastically tailored wings of dragonflies inspire to design of more effective wings for MAVs and NAVs.Yu Chong Tai  developed the first electrically powered palm size ornithopter was flown for 9 seconds in October 1998, which powered by two 1- farad super capacitor as his first prototypes. The second prototype houses a small 3-gram rechargeable NI-Cad Battery and the best performance lasted 22 seconds. Moreover, they studied the flapping wing flight in the wind tunnel using wings developed by MEMS technology.The conventional way to construct the wing is to build the wing spars and its membranes from the light yet very strong materials. They first built the model using Carbon fiber rod with 750mm diameter as wing frames. Thin Mylar or thin paper glued to the carbon rods as the wing membranes. This method of constructing the wing is cumbersome and need to consider:1) Glue adds weight and wing becomes too heavy2) An identical set of wings are difficult to achieve unless molds are made for each fabrication3) It is costly, time-consuming and has low turnaround time.MEMS wing enables systematic research in term of repeatability, size control, weight minimization, mass production and fast turnaround time, in addition to this, a complicated structure such as dragonfly, butterfly, and beetles wing can be easily fabricated using photolithography technology. They have chosen the titanium alloy (Ti-6A1-4V) because of it’s lightweight, strong and can easily taper to vary the thickness of wing pars and titanium alloy is ductile allowing bending to create wing camber to improve performance. For wing membrane parylene – C, as1. It can be deposited directly onto titanium alloy at any desired thickness2. Its adhesion to titanium- alloy is excellent3. It is light and strong and can withstand high flapping frequency of more than 30 hertz without tearing4. It is a deposit at room temperature and yields a conformal coating. Based on simplicity, minimal weight, flapping symmetry, the design of C was implemented and built with a small DC motor with gearbox ratio of 22:1, which used to drive the transmission, which powered by 1.5 watts. The Wings ware mounted on the transmission system and several flapping tests were performed and can withstand more than 30 hertz of flapping without breaking or tearing.A high-quality low-speed wind tunnel with velocity uniformity of 0.5% and speed from 1m/s to 10m/s was operate taken using the low capacity 2-D force load cells.His result provides the following statements:1. The spanwise stiffness is an important factor in lift production in flapping wing2. The leading edge produce larger lift coefficient compared to those with flexible lading edges3. At the start of the downstroke, the flow stagnates at the leading edge of the wing.4. The stagnation line progressively moves to the upper surface of the wing thereby forming a leading edge vortex which continues to grow and its maximum size at about the middle of the downstroke and then starts the upstroke.5. Because of light and rigid nature, the real wing shows better wind tunnel test result than nature mimics Mems wings.6. The latest Microbat prototype was designed with battery powered with a radio control system which flown on 7 December 2000 for 42 seconds on its first flight.The key to the time limit of flight is due to the power sources, which remains an impotent issue.Benjamin J. Goodheart Aviation historians as tower jumpers often refer to the earliest of those to experiment with flapping wing devices. In keeping with his