WEALTH CREATION AN AIRCRAFT LIKE NO OTHER Testing an aircraft that is the size of the Airlander in private is impossible, so the first test flight in August 2016 was watched by a crowd of onlookers at the former RAF station in Cardlington, Bedfordshire, which is home to the craft © Hybrid Air Vehicles INGENIA ISSUE 71 JUNE 2017 27 AN AIRCRAFT LIKE NO OTHER WEALTH CREATION The Airlander made headlines when it embarked on its first test flight in August 2016 as the world’s largest aircraft. Science writer and broadcaster Geoff Watts talked to Chris Daniels, Head of Partnerships and Communications at Hybrid Air Vehicles Limited, and David Burns, Airlander’s Chief Test Pilot, about the engineering that helped it reach this stage and plans for the craft’s future. AIRLANDER: A BRIEF HISTORY Airlander 10’s manufacturer, Hybrid Air Vehicles (HAV), was set For more than a century, above the weaknesses that up by Roger Munk in 2007. Its first customer was the US Army airships of various kinds have have eventually sunk so many who needed an unmanned aerial surveillance craft for use in been seeking a sustainable previous forays into this most Afghanistan. The craft had to be able to fly for long periods, and commercial role. So far, no eye-catching form of transport. at altitudes of up to 20,000 feet, out of range of local weaponry. venture has lasted indefinitely, HAV was to asked complete its part in the $500-million-dollar but now, British company programme in the extraordinarily short period of 25 months. It Hybrid Air Vehicles (HAV) is UNUSUAL DESIGN did so, and a successful test flight of what was then called the confident that it has found the Seen from the side, Airlander HAV 304 took place in New Jersey, USA, on 7 August 2012. It was way forward. New materials, looks like most other craft of to be the only such outing. Defence budget cuts and the US new technologies, and most its kind. However, the view government’s increasing determination to get out of Afghanistan importantly, new thinking from any other angle reveals it led to the demise of the programme. By the time it was axed, $300 have combined to produce to be quite different. It has an million had already been spent. From the back, the Airlander resembles three sausages that have been squashed together, an arrangement that creates an aerodynamic shape, which is assisted the newest breed of airships: a oval rather than round cross- HAV saw its chance. The company had a proven craft for which by two top fins and two lower fins – one of which can be seen before it was attached to the hull © Hybrid Air Vehicles 92-metre craft called Airlander section, while it resembles a the development costs had been paid, but for which the US Army 10. Its capacity for landing pair of fat sausages pressed no longer had a use. There being no competing bids, HAV was AIRSHIPS BY TYPE mode of flight. While traditional metres of fabric made up of anywhere without large side to side when viewed from able to buy the craft back for a mere $301,000, virtually scrap airships, almost by definition, multiple layers of three materials: Airships or dirigibles numbers of ground staff and, the front. When seen from the value, and less than it cost to dismantle it, roll it up, and ship it have relied on their inherent Vectran, a fibre spun from a Any powered aircraft that is steerable, and inflated with a gas if necessary, staying airborne rear, those two sausage shapes across the Atlantic. On arrival in Cardington in December 2013, it buoyancy, Airlander is slightly liquid crystal polymer and often lighter than air. for weeks at a time offer clear have morphed into three. was repaired, reassembled and reinflated. Some 500 modifications heavier than air and its default used in high-performance sails; advantages in performing all This configuration creates an later, and with the support of private investors and grants from the Blimp direction of free movement is Mylar, a tough polyester film sorts of tasks. aerodynamic shape and the UK government, Airlander 10, as it was now called, was ready for A powered, steerable, lighter-than-air vehicle with no rigid not up but down. Only when in to ensure that the envelope Unusually, Airlander forward movement of the craft its first test flight. internal structure. Its shape is a consequence of the pressurised motion does it generate the lift (structure) is helium-tight; and combines the features of generates lift. gas within it. it needs to start rising. Airlander Tedlar, a vinyl fluoride polymer traditional airships with others The origins of this innovative airships and headed the design a clutch of key hurdles. These Semi-rigid airship combines the cost efficiency with good resistance to weather derived from heavier-than- design lie with the late Roger team responsible for the R100, a ranged from the use of An airship incorporating a limited rigid frame, typically a keel, to of an airship, with some of and chemicals. These materials air machines. Not all its lift is Munk, a British engineer born craft that had intended to offer stronger and lighter plastics support it and distribute loads. the performance virtues of an were heat-welded to form a provided by the buoyancy of in the late 1940s, who became mail and passenger services and composite materials to the Rigid airship aircraft. single thin, flexible yet remarkably the gas within its hull: up to 40% fascinated by airships and to the countries of the British introduction of more advanced An airship with a shape fully defined by a complete internal Unlike most of its large tough sheet. Delivered to the is a product of its aerodynamic then set out to find a way of Empire but was grounded after a flight control systems. framework. predecessors, Airlander has no manufacturing site in rolls, it was shape. It is this innovation in making them a mainstream flight to and from Canada in the Over the years, Munk tackled internal framework. Its shape cut to shape before the individual Hybrid airship aeronautical engineering, its transport system. One of Munk’s 1930s. Sir Barnes told Munk that them all. His key insight was derives entirely from the pressure sections were assembled by An airship that relies on aerodynamics as well as the gas within it hybrid status, that HAV believes inspirations was Sir Barnes Wallis the future success of airships the feature that sets Airlander of the gas within its hull, which heat-welding. Most existing to provide lift. will allow Airlander to rise CBE FRS, who had worked on would depend on overcoming apart from its predecessors: its comprises some 7,000 square airship hulls have been made out 28 INGENIA INGENIA ISSUE 71 JUNE 2017 29 AN AIRCRAFT LIKE NO OTHER WEALTH CREATION found themselves teaching the simulator rather than vice-versa. The experience of a take-off is of polyester, which can stretch not unlike that of an ordinary when subject to pressure, but the aircraft but in slow motion, and material used to construct the Airlander has four ballonets (seen in yellow), or air-filled balloons, within its hull. These serve to maintain the helium in as with large sea-going ships, Airlander is more resilient. the hull at a constant pressure difference with respect to the outside air. At ground level the ballonets, which are made the response to adjustments of of the same material as the outer fabric and connected via four vents to the exterior, occupy up to a third of the volume Weight and strength are of the craft. As the craft rises and the outside air pressure falls, the helium expands, expelling air from the ballonets, the controls is not instantaneous. key factors when making the while on descent the reverse happens. The movement of air into the ballonets is aided by large fans set in the openings Four 325 horsepower turbocharged engines with variable pitch propellers power the Airlander. They are lighter than Although Airlander can choice of any components for to the exterior © Hybrid Air Vehicles engines that were used for previous generations of airships and the absence of a rigid interior framework means that they need to be attached directly to the fabric structure of the craft © Hybrid Air Vehicles operate anywhere from the an airship, not just for envelope valves that normally allow the to nil) in natural gas. Although be anticipated. The remaining tropics to the Arctic, it is not of the hull. HAV used Forward helium to move freely between helium is a finite resource, HAV two engines, each mounted polyester fibres encased in a The avionics are as advanced Using a pair of skids running wholly immune to weather Composites to make many them, but can be closed if insists – in spite of occasional on the conical rear tips of the durable black polymeric sheath. as those of any modern aircraft, lengthwise beneath it, the craft conditions. Its 30 tonnes of of the larger components of required to isolate individual claims to the contrary – that we hull, are supported by forward- At speeds of up to 30 knots, but adapted to take account of a can land on any surface. Pilots weight give a stability that Airlander’s rigid structures. The sections. In contrast with the are not yet in imminent danger running carbon composite the craft is mostly steered by very different mode of flight. The can practise this and other allows it to function even in carbon and glass composites high-tech materials science of running short of it.