Introduction

The flying wing concept, vertical tailless aircrafts in particular, dates back to more than 100 years in the history of human flight and its proponents advocated this design for better efficiency than other conventional designs. Hugo Junkers (US), an early enthusiast, patented the idea for a wing-only air transport in 1910. The Horten brothers (Walter and Reimar) in Germany used the same concept in developing their prototype Ho-229, during the later stages of World War II. The works of Ludwig Prandtl were instrumental for their design. Jack Northrop (US) demonstrated the same idea through his prototype YB-49 that later paved the way for Northrop Grumman in developing the B-2. It took the advent of fly-by-wire platform to coordinate the complex flight characteristics of B-2 and achieve a realistic flight of the stealth flying wing concept. A more advanced next generation B-21 is in the making.

An offshoot of flying wing concept is the blended wing body (BWB) design that originated with a futuristic study on advanced technology subsonic transport by NASA Langley Research Center and McDonnell Douglas (now Boeing), three decades back. In contrast to the flying wing design, the blended wing body design has a distinct looking fuselage and may or may not be tailless. The smooth shape of both designs produce very little drag, which means they are more fuel-efficient and probably fly faster than a conventional aircraft design using the same engine. Being said about the efficiency and the stealth characteristics of the flying wing or blended wing body designs, they lack the agility and maneuverability of modern day fighter aircrafts. Additionally, as they lack conventional stabilizing surfaces and the associated control surfaces, these designs in their purest form suffers from the inherent disadvantages of being unstable and difficult to control during stalling, in case the engine cuts out.

Even though the BWB design is often presented as a hypothetically efficient aircraft design for the future, there are many practical challenges to be overcome as a commercially viable design. Most of these drawbacks or challenges are due to the lack of tail section.  In view of that, Lockheed Martin proposed a Hybrid Wing Body (HWB) version with an addition of conventional T-Tail section. The BWB design is often viewed as design solely for high-capacity aircraft like Airbus A380, partially because of NASA’s original criteria of 800 passengers over 7000 nautical mile range at a Mach number of 0.85. However, this is not the case as the BWB design is successfully employed in several new generation unmanned combat air vehicles (UCAV). Northrop Grumman demonstrated the BWB concept in recent years through their unmanned combat air vehicle (UCAV) prototype X-47B. Other blended wing body type UCAVs under various stages of development are S-70 Okhotnik of Sukhoi, Skat of Mikoyan, Taranis of BAE systems and nEUROn of Dassualt Aviation.