Tiltrotor and other V/STOL for future urban aviation
While large airports will always exist, flight to city centers is inevitable.
By Ken Solosky
ATP/Helo/CFI Chief Pilot, Newark Police Av Unit
Futuristic scene from Washington DC showing the tiltrotor concept fully operational. Some manufacturers see the 200-mile mission as the proving ground for VTOL aircraft.
Transportation between major cities has always been a major headache. Railroads require considerable land, capital resources and intensive maintenance. Cars and trucks are heavy polluters and jam highway systems designed 60 years ago for far fewer and much slower cars.
The traffic jams of New York and Los Angeles have become infamous. Even Hollywood capitalized on LA’s traffic jams in the 1993 film Falling Down, starring Michael Douglas, which started with him walking away from his car stuck in freeway traffic.
Congestion in the form of traffic jams costs millions of dollars in lost time, productivity and wages annually. Several years ago, Bell Helicopter concluded that vertical lift would be the leading technology to meet future transportation needs between major cities.
Recognizing that many cities around the world fall on a radius of about 200 miles, and given the growing scarcity of land needed for runways and airports, vertical-lift technology seemed the obvious answer to this critical need.
New York and Washington DC-206 miles apart-and London and Paris-213 miles-are just 2 examples of major metropolitan areas that could be served by fast, efficient, reliable vertical-lift technology.
Even NASA has weighed in on the issue and supports vertical-lift technology as the most efficient transportation system for trips of approximately 200 miles. Today this 200-mile mission is carried out primarily by conventional helicopters.
BA609 performs at the 2007 Paris air show. Bell/Agusta has more than 80 orders for its civil tiltrotor. Certification is expected in 2011.
All manufacturers are represented in the missions flown-in the corporate world the Sikorsky S76 is hugely popular, although Bell and Eurocopter maintain a strong presence. Conventional helicopters do have several limitations.
They are currently aerodynamically limited in speed, due in part to the intractable problem of retreating blade stall. Helicopters have fairly limited range and often have a small useful load, and they must also fly at relatively low altitudes.
Considering that today most major metropolitan airports are operating at or above capacity, and that the mere suggestion of additional runways raises environmental, noise and cost issues, it is no wonder that “alternative” technologies are being investigated.
Factoring in air traffic control considerations, it’s clear that the current system has reached a logjam and that a long-term fixed-wing solution appears unlikely.
Research into tiltrotor technology is hardly new. Bell Helicopter actually began testing the technology in the late 1940s and flew its XV3 from the mid-1950s until 1966. This early research proved the basic concept-tiltrotors could fly.
In 1955 the Bell XV3 became the first tiltrotor aircraft ever flown. Bell’s research with the XV3 not only proved the concept but was later applied extensively to the XV15 program.
Bell saw the tiltrotor as solving the limitations of conventional helicopters and bringing the advantages of fixed-wing aircraft such as speed, range and useful load. In the late 1970s and early 80s, the US military resurrected the idea of an aircraft that could operate as both helicopter and airplane in order to help them fulfill a wide variety of missions.
The failed Iranian hostage rescue in 1980 was one pivotal event. This mission brought home to the military the limitations of helicopters specifically, the mission posed a challenge in terms of its fairly long range for helicopters, while speed and refueling considerations in the desert contributed to the mission failure.
The Bell/Boeing V22 program was born. Its civilian cousin, the Bell/Agusta BA609, was to follow in the mid-1990s. Unfortunately, logistical problems still abound for the long-term and continuous support of tiltrotors-in most major cities today there are precious few heliports in existence that could support continuous landings and takeoffs of tiltrotors.
For example, in New York City, of the 3 operating heliports, it appears that only JRB (Downtown Manhattan/ Wall St, New York NY) could support currently proposed civil tiltrotor aircraft. A question exists as to whether heliport operators can be convinced to expand their facilities to accommodate tiltrotors without any assurance that they will ever come in sufficient numbers to justify their renovation costs.
Price of the aircraft itself has also been a factor. Although Bell/Agusta has never formally announced a sticker price, original projections and estimates placed the price at approximately $10–12 million.
Bell XV15 lifts off at Dryden Research Center in California. The XV15 served as a major research and development platform and was directly instrumental in the development of the USMC V22 Osprey.
Since those projections and estimates are nearly a decade old, the price will certainly have risen. Bell/ Agusta claims to have more than 80 orders for its BA609 tiltrotor, which is slated for certification in 2011.
Another factor that has affected the entire tiltrotor concept is the extensive media coverage of accidents of the V22 Osprey during operational testing. Many critics were quoted as claiming the technology was fundamentally unsafe.
Then-Vice President Dick Cheney was also a critic. He proposed eliminating the V22 program, citing cost and operational difficulties. Although it appears that Boeing/Bell/Agusta have surmounted the issues and causes of these early accidents, the negative publicity is likely to remain in the minds of corporate flight managers and the public for some time.
Looking into tomorrow
Obviously, the cost of this technology will play a considerable role in the development, acceptance and use of tiltrotor aircraft. Given the state of the worldwide economy, it is safe to say that both manufacturers and aircraft operators will examine research and development carefully, as well as manufacturing costs.