DEVELOPMENT OF A BLENDED WING CONFIGURATION

MAV

ByA.SATYA JAYANTH

(08Q91A2102)

ABSTRACT

Micro air vehicles “MAV” belong to a class of aircrafts currently with a maximum size of 300mm and are capable of operating at speeds of not less than 12m/s. MAV’s are expected to find applications in border patrol, visual surveillance etc. MAV’s are typically characterized by a low aspect ratio wing operating at low Reynolds's numbers (10^5 ~ 10^6). A camber plate MAV of 300mm wing span generates cl of 0.7-0.8, comparatively blended wing MAV generates cl of 1-1.3 this motivates the work to be carried out. This work contains the aerodynamic design, airframe modeling, production and development of a blended wing MAV.

WHAT IS BLENDED WING BODY?

Blended Wing Body (BWB) aircraft have a flattened and airfoil shaped body, which produces most of the lift, the wings contributing the balance.

BWB incorporates design features from both a futuristic fuselage and flying wing design.

NASA BWB (blending wing body)

X-48 AIRCRAFT

ADVANTAGES

Blended wing body has lift-to-drag ratio 50% greater than conventional airplane.

Efficient high-lift wings and a wide airfoil-shaped body.

Its fuel burn will be 27% lower than its conventional Airbus.

Take off weight 15% lower.

Empty weight will be 12% less.

It will only require three instead of four engines, and will match or exceed conventional performance, despite having 27% less thrust.

It is lighter.

More fuel efficient.

Requires far less power.

More aesthetic in appearance.

HISTORY ABOUT BLENDED WING CONFIGURATION

Stout Batwing first blended wing configuration… in 1926

Micro Air Vehicles (MAV)

Micro air vehicles belong to a class of aircraft currently designated with a class of size 300mm and are capable of operating at speeds of not less than 12m/s.

They are typically characterized by low aspect ratio.

MAV’s are a class of small light-weight aircrafts designed to operate in situations that are practically unsuitable for large aircrafts.

MAV’s are used for battlefield reconnaissance, visual surveillance, border patrol, air sampling for civil services.

STEPS INVOLVED IN DEVELOPMENT OF A BLENDED WING BODY AIRCRAFT

(MAV)

AERODYNAMIC STUDIES

The aerodynamics of the aircraft is greatly affected by airfoil, operating chord based Reynolds number, plan form shape and wingtip devices like winglets.

AIRFOIL SELECTION AND ANALYSIS

The number of airfoils are referred from various technical papers.

Performance studies on number of aircrafts indicated that GM78, J5012, MH45 are the three airfoils having better performance and meets the requirements of Blended wing MAV.

GM78

J5012

AIRFOIL AOA Cl/Cd Cl

GM78 7° 70% 1.2

J5012 7° 55% 0.7

MH45 7° 70% 1.0

This comparison of aerodynamic performances shows that the GM78 is the best suitable airfoil for a blended wing aircrafts.After that selection analysis is to be done.

PLANFORM DESIGN

Chosen plan form designs are

Fig.1 Fig.2 Fig.3

After the comparison of the performance analysis of the three plan forms the inverse Zimmerman plan form (fig.3) is chosen to be the best.

With and without winglet the graph of Cl and α is

STABILITY AND WINGLETS

Directional stability is associated with angular motion about the z-axis.

Vertical wing is the conventional mechanism for directional stability.

Winglets with 90° can help to reduce the induced drag.

Winglet sizing is done by vertical tail volume coefficient.

AIRFRAME AND SKIN PRODUCTIONFINAL ASSEMBLY AND FINAL TEST

Airframe is a skeleton of MAV and is prepared by the composites of Kevlar and Rohacell.

Using a technique named rapid prototyping is used in the mechanism of skin material.

Blended wing model is prepared for testing.

Blended wingMAV model

CONCLUSION

A light weight micro air vehicle as been developed through a systematic approach with a blended wing configuration.