V/STOL TECHNOLOGIES

Innovation offers needed lift for the rotorcraft of tomorrow

Strong commitment to R&D and inspired concepts are key to advancing the forefront of vertical lift capability.

By Don Van Dyke
ATP/Helo/CFII, F28, Bell 222
Fellow of the Royal Aeronautical Society


Eurocopter X3 (X-Cube) is an experimental compound helicopter under development and intended to fly at speeds exceeding 220 kts.

Consider today's AgustaWestland AW101. Its configuration is not vastly different from that of the Sikorsky SH3 Sea King, which predates it by 40 years. Notwithstanding the Bell Boeing V22 tiltrotor, the speed of most military and commercial helicopter designs has not changed significantly since the Vietnam war.

Since helicopters are the most mechanically complex systems currently flying, this evolutionary development was usually adopted because it bears less risk than revolutionary change.

However, rotorcraft companies tend to keep a close hold on information about future concepts. Traditional models for close control of intellectual capital and data may well be our Achilles' heel as we become more dependent on the open source collaborative workplace that has stimulated explosive growth in Internet-based industries.

The key to innovation is openness and access to disparate ideas and state-of-the-art tools.

Significant innovations have gone into these aircraft at the component level, resulting in greater safety, efficiency and performance. But innovation is broader than technology and, more importantly, is critical to economic prosperity.

Safety goals

Despite small safety performance gains, the damning verdict delivered at the latest Intl Helicopter Safety Seminar (IHSS) is that global helicopter operators are nowhere near on-track to meet the accident-rate reduction target set in 2005.

The Intl Helicopter Safety Team (IHST), hopeful that the objective can still be achieved, concluded that 2011 marked the transition from data gathering and policy development to the policy implementation stage. Beyond this point, safety deliverables could reasonably be expected to show results.

Detailed regional analysis of helicopter accidents across the world shows that rotary-wing crashes happen for much the same reasons.

The top global industry problems are the lack of a risk management culture at operator level and poor pilot judgment when an accident situation develops. At least part of the answer may lie in enhancing situational awareness, reducing crew workload and improving crashworthiness.

Operating goals

Sikorsky X2 technology demonstrator, now succeeded by the S97 Raider high-speed scout and attack helicopter.

Historically, vertical flight has required a compromise be­tween hover performance and forward speed. Desired helicopter attributes include good hover efficiency, low speed controllability, reduced downwash, hover endurance and speed.

Its operational focus is to serve markets not served by airplanes while improving safety and security. Operators need quantum gains in performance, including greater cruise speed, greater range, improved lift and enhanced agility.

Market needs and drivers

Sikorsky X2 technology demonstrator, now succeeded by the S97 Raider high-speed scout and attack helicopter.

Much of the current global fleet is over 30 years old, including a number of 1970s helicopters still flying. Irrespective of market growth, an important and sustainable element in the market is just about replacing the aging helicopters still in operation.

Although there has been a downturn in recent years, OEMs have been running at full capacity with reduced staff, particularly in the civil market. Rolls-Royce is confident of long-term growth over the next 10 years until 2020.

Its recent market outlook up­date —Rolls-Royce Market Overview: 10-Year Helicopter Industry Market Forecast, 2011–2020—predicted turbine rotorcraft deliveries to reach more than 16,400 units over the period, split between a civil market of 10,300 civil helicopters valued at some $38 billion and 6100 military helicopters valued at $108 billion.

The business helicopter market is driven by speed, range and size. In addition to normal market growth, as emerging-country markets develop, an underlying demand will be generated by replacement.

Market drivers include the global economy, wealth creation, utilization, backlogs, preowned aircraft market, new aircraft programs, market accessibility and climate change.

Edge of innovation—printing a flyable aircraft

BLR Aerospace FastFin reshaped vertical fin.

Printing an aircraft direct from a computer may sound far-fetched but, in Aug 2011, the University of Southampton, England, announced it had flown the first 3D printed unmanned air vehicle (UAV)—a possible precursor to the way future products are designed and manufactured.

Additive manufacturing is defined as the process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing such as traditional machining. This net shape capability only makes what is needed—no more, no less.

To create a stronger object that can withstand higher loads and stresses, an electron beam can be used in place of a laser to melt the powder particles completely. Because 3D printing involves no cutting or grinding of metal, it offers vast design freedom.

This is huge for aircraft designers, since some of the best ideas in aviation have involved designs which proved too pricey and tough to make. The Vickers Supermarine Spitfire, for example, was among the most maneuverable fighter aircraft of WWII because its wings were of an ultralow-drag elliptical design. But it was a nightmare to produce, requiring complex machinery and production expertise.

With 3D printing, designers can go back to pure forms and explore airflow mathematics without being constrained to straight lines to keep costs down.

The following survey of aerospace innovation is neither comprehensive nor complete. It simply highlights certain promising areas which may spark further creative thought, particularly among those who may not have come across these opportunities previously.

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