BLENDED WING BODYFUTURE OF AVIATION

PRESENTED BY:- ASIM KUMAR GHATAK V SEMESTER MECHANICAL ENGINEERING JSS ACADEMY OF TECHNICAL EDUCATION NOIDA

CONTENTS1. INTRODUCTION2. BRIEF HISTORY OF BWB3. HOW AEROPLANES FLY?4. SOME ORGANISMS WITH BWB5. DESIGN AND STRUCTURE OF BWB6. CONVENTIONAL AEROPLANES Vs. BWB7. ADVANTAGES AND DISADVANTAGES OF BWB8. FUTURE SCOPE AND CHALLENGES9. CONCLUSION10. REFERENCES

INTRODUCTION Blended Wing Body (BWB) aircraft

have a flattened and airfoil shaped body, which produces most of the lift, the wings contributing the balance.

A BWB aircraft is a configuration where the wing and fuselage are integrated which essentially results in a large flying wing

Theoretically it can carry up to 800 passengers at a Mach number of 0.85

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

The advantages of the BWB approach are efficient high-lift wings and a wide airfoil- shaped body.

This enables the entire craft to contribute to lift generation with the result of potentially increased fuel economy and range.

BRIEF HISTORY OF BWB

Northrop N1M “Jeep”, by Northrop Corporation, USA

The concept of Blended Wing body was introduced almost 27 years ago.

The idea was to build a new type of aircraft that would allow the aircraft to carry more passengers.

[1]

Horten Ho I by Horten Brothers, Germany

The BWB aircraft is not a fully novel concept because it was considered by Horten, Northrop, and others from the mid 1930s to the mid 1950s.BWB aircraft was previously called “Tailless Airplane” and “Flying Wing Aircraft”.

Turbojet powered Ho-229 flying wing aircraft the world's first turbojet-powered flying wing air- craft, the Ho-IX (Source: Military Factory).

The Northrop semi-flying wing aircraft 1928(Source: Smithsonian NASA Museum).

Northrop XB-35 piston-engined long-range bomber 1946 (Source: Virtual Aircraft Museum).The Northrop XB-35 aircraft, which came

into service in1946, is powered by four piston engines, each driving two contra-rotating four-blade pusher propeller through a long shaft and gear box.

The Northrop N-1 M Aircraft 1940( Source: Smithsonian NASA Museum).

The Northrop N-9M aircraft (Source: Smithsonian NASA Museum).

The N-9M was developed as a scaled mock-up of the proposed bomber. The N-9M is an18m span twin-engine aircraft with a take-off weight of 6326kg.

The D-8 tailless aircraft at the 1914 Farnborough airshow

‘B2-Spirit’ Stealth Bomber 1981( Source: Xairforces Military Aviation Society).

The first recorded tailless flying wing aircraft was the D-8 aircraft designed by John Dunne in1911

HOW DO AEROPLANES FLYLIFT

WEIGHT

THRUST DRAG

LIFT

DRAG

THRUST

WEIGHT

Lift is the force created by the interaction between the wings and the airflow. It always act upwards. Lift must exceed weight for flight.

This force acts in reverse direction to that of 'Thrust' and hinders forward motion. Drag is considered as a negative force.

This force is created by an aircraft's engine and is required for forward motion.

This force acts on an aircraft due to the interaction between the aircraft's body weight and Earth's gravity.

FL= CL*0.5*ρ*A*V2

FD= CD*0.5*ρ*A*V2

1

3

2

LIFT

4

6

5

BY BERNOULLI EQUATIONAND MAGNUS EFFECT

The wake of a Boeing 767 disrupts the topof a cumulus cloud and clearly shows thecounter-rotating trailing vortices.[2]

F L

F L

F L

F D

F D

F D

At large angles of attack (usuallylarger than 15°), flow may separatecompletely from the top surface of anairfoil, reducing lift drastically andcausing the airfoil to stall.

(a) 5°

(c) 30°

(b) 15°

(b) 15°

Aircraft Control Surfaces

FlapsAileronsSlatsRudderElevatorsFlaperonsElevonsSpoilersVortex GeneratorsWinglet

ORGANISMS THAT HAVE BLENDED WING BODY

MANTA RAY

GLIDING SMOOTHLY IN GOTHAM CITY

DRAG… WHAT IS IT?

THRUST. HUH..DON’T NEED IT

WEIGHT!!! DO I LOOK FAT TO YOU?..

PHYSICS DON’T APPLY TO KRYPTONIANS

DESIGN AND STRUCTURE OF BWB

Northrop Grumman B-2 Spirit Stealth bomber

First flight: July 17, 1989Length: 21 mWingspan: 52 m

DESIGN AND STRUCTURE OF BWB

[3]

[4]

[5]

VELA 2 baseline concept[6]

DESIGN AND STRUCTURE OF BWB

Cambridge MIT silent aircraft concept (Source: The Cambridge-MIT Institute). [7]

The ACFA BWB configurationThe project called Active Flight Control for Flexible Aircraft is the design of an innovative ultra efficient 450 passenger capacity BWB aircraft with highly swept back center-body and 2 podded turbofan engines [8]

DESIGN AND STRUCTURE OF BWB

CONCEPT OF WINDOWLESS AIRCRAFT[9]

BWB CONCEPTUAL SEATING ARRANGEMENT[10]

BOEING X48C PROTOTYPE (2011)[11]

CONVENTIONAL AEROPLANES VS BWB

Transformation of a 650m2 ball into a conventional and BWB aircraft [12]

PERFORMANCE COMPARISON BETWEEN A CONVENTIONAL AND BWB CONFIGURATION[14]

[13]

LIFT Vs WEIGHT DISTRIBUTION

[15]

[16][17]

NO WINDOWS!!!

Each seat will have a multifunctionalLCD screen on the seat in front of them. Aselector will allow the passenger to select from a number of views, including looking to the rear and straight down.It can be used as a cargo plane as it has large space and there is no problem of internal pressurization.

[18]

ADVANTAGES AND DISADVANTAGES OF BWBADVANTAGES :-Aerodynamics: The aerodynamic benefits of the BWB are derived from the integration of its ‘fuselage’ and wings to obtain ‘low wetted surface area to volume ratio’ and reduced interference drag. This lowers total drag and provides higher L/D ratio compared to conventional configuration

DOC- direct operating costs includes Fuel Landing fees Maintenance Annual inspection

[19]

Increase in the passenger capacity up to 800 Reduction in fuel consumption of the aircraft(burns 27%

lesser fuel) High L/D ratio due to a decreased relative wetted area(area

which is in contact with the external airflow) Favorable load distribution along the span Possible engine noise shielding 15% lower takeoff weight 12% lower empty operating weight 27% lower total thrust 27% lower fuel BURNED 20% higher L/D ratio as compared to conventional aircraft Lower production cost (lower production costs come from not

have as many tight bends so the manufacturing costs go down)

Lower fares Reduced airport/airspace congestion Improved safety

ADVANTAGES :-

ADVANTAGES AND DISADVANTAGES OF BWBDISADVANTAGES :-

High bending stresses resulting from the effect of pressure on the box-like shape of the BWB

High bending stress associated with a non-cylindrical pressure vessel.

typical aircrafts have a cylindrical shape which requires less strength and is easier to pressurize as opposed to the interior shape of a BWB.

[20]

Evacuating a BWB in an emergency could be a challenge. Because of the aircraft’s shape, the seating layout would be theatre style instead of tubular. This imposes inherent limits on exit doors. (90 seconds evacuation)

As engines are placed above the rear fuselage. Air safety authorities have expressed concern that in an accident they could become detached and their momentum carry them forwards so that they fall onto the passenger cabin.

“Bulging” at the outer surface will occur as the aircraft is pressurized. This will deform the elegant cruise airfoil shape that is being planned, so it has to be taken into consideration in the design.

The two decks also raised concerns over passenger safety in a crash situation where the upper deck could collapse onto the lower one.

As there will be no windows, people will feel air sickness. And by integrating a giant LCD in the partition wall might cause some people nausea.

The last issue was how to you handle 800 passengers as several terminals are not designed to handle that volume of humanity.

DISADVANTAGES :-

FUTURE SCOPES AND CHALLENGES

With the increase in population exponentially we cannot have a congested traffic in the mid air or an “Air Traffic Jam”. So we need some new innovation which can carry more passengers, have a small size and less pollutant and can integrate new thrust mechanisms like hybrid engines and produce less noise and take less runaway for take off and landing and terminal congestionWith these factors in consideration we can assume that by 2020 the world might see the BWB in their airport with its eye catching design and body like an UFO.

Challenges ahead Structural and material (structural – wingspan exceeds 262ft. Or 80m)& (Structures is

back to the pressurization issues and the integration issue revolves around making the structure clean enough to work aerodynamically and achieve the savings potential.)

Aero structural integration Aerodynamics Controls System integration Infrastructure

CONCLUSION The BWB is fuel efficient Less material required to produce the body Less complicated design Less noise High L/D ratio Carry more passengers Less size compared to conventional aircraft Aerodynamic design Less pollutant Can integrate new hybrid turbines AND turboprop fans From the conceptual point of view, the BWB design has been

demonstrated to be more attractive than the conventional aircraft. The flight features of small drag value and less engine thrust requirement

predict to perform with less noise emission, and make it a more environmentally-friendly vehicle.