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40 Years Retrospective: Power and Vision

By James T. McKenna | August 1, 2007
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Evolution, not revolution, describes the change in vertical-lift technology since 1967. The pace has satisfied no one. But there have been significant changes, perhaps none more important than the advent of the turbine engine and IFR flight in helicopters.

LOOKING BACK OVER THE LAST 40 YEARS OF ROTORCRAFT development, it is not hard to sort out the most significant technological advances. There are not that many from which to choose.

Since Rotor & Wing published its first monthly issue in January 1967, the rotorcraft industry almost universally has focused on finding more efficient ways to work with the equipment it has than in working out means of leapfrogging those capabilities. As many an observer will remark, the history of this industry has been one of evolution rather than revolution. That evolution, however, has been rather slow. Glacial might be a more accurate description.


Therefore, the technological barriers well known in 1967 — in the form of physical limits on helicopter speed and political and social barriers on its broader acceptance as a safe, friendly, and efficient means of transportation — remain before us.

Piasecki Aircraft just over a month ago began flight tests of its XH-49A SpeedHawk compound helicopter aimed at solving the speed question. Sikorsky Aircraft hopes to fly its X-2 technology demonstrator by year’s end with the same goal in mind. That’s about where Lockheed was when we first started publishing. It first flew its AH-56A Cheyenne compound helicopter in October 1967. The U.S. Army would cancel the program within a year because of stability problems.

Likewise, the combination of fixed-wing and rotary-wing flight capabilities promised by the NASA/U.S. Army/Bell Helicopter XV-15 program and the subsequent Bell/Boeing V-22 and Bell/Agusta BA609 have to be fulfilled. The V-22 is only now going into combat, and the civil BA609 is still years away from certification and entry into service.

There was a lot of talk back then of helicopters in every garage, figuratively speaking. But rotorcraft were noisy things and less reliable than airplanes. Plans for a national network of heliports in the United States never came to pass, and skepticism about the aircraft that would use them was one reason, among many others.

Our first issue was timed to coincide with the Helicopter Assn. of America’s annual convention in Palm Springs, Calif. That event included a panel discussion on the prospects for the helicopter in the corporate aviation market. The consensus of that panel, Francis McGuire writes in his contemporary history for that group’s successor, the Helicopter Assn. International, was that "the helicopter’s reliability and lack of IFR capabilities still made it unsuitable for corporate operations."

"By the time the January 1967 Helicopter Assn. of America convention rolled around, the helicopter world was agog with new technology developments," McGuire writes in that book, "Helicopters: 1948-1998."

There was talk of steam-powered aircraft, from a number of precincts. Bill Lear was developing a steam engine that "uses a secret fluid rather than water and would be rated at 300 hp." Thermodynamics Systems of Newport Beach, Calif. fitted a 150-shp steam engine on a Hughes 300.

In surveying industry leaders and experts about the most significant technological advances of the last 40 years, the top contenders — widespread use of turbine engines and instrument flight capability — don’t quite fit into that four-decade time frame. Sud-Est, after all, had introduced the turbine-powered Alouette 2, in 1955. At the 1967 show where R&W debuted, the aircraft on display included Bell Helicopter’s newest JetRanger models and Fairchild-Hiller’s FH1100 — turbine-powered all. By that time, operators in the North Sea had long been IFR-capable helicopters.

Still, acceptance of the turbine and the successful fight to gain instrument flight rule (IFR) certification for helicopters in the United States top our list of the most significant advances, technically speaking. Others on the list piggyback quite a bit on the phenomenal advances in computing capability since the mid-1960s, those being avionics systems, full-authority digital engine controllers, and simulation and flight training devices. The last is related to another noteworthy advance: the effort to improve rotorcraft safety. Last, but far from least, is the broad and growing use of composites in rotorcraft structures and components.

Underlying all of those, however, is one that is not so apparent because it is generally viewed as a political development: the formation of the European Union. That federation pooled the funding of its member nations, which now number 27, and tamed somewhat the competing interests of national industries. Perhaps most importantly in our respect, it united those nations in a common plan to target and fund research and development in critical technologies, among which is vertical flight. Those plans are now in their sixth iteration.

That investment has come as the United States has starved its rotorcraft industry of R&D funding for years.

This is one of many reasons why Eurocopter and AgustaWestland have made major gains in U.S. markets in recent years. Most notably among these was AgustaWestland’s win as the airframe partner of the VH-71A presidential helicopter contract. Eurocopter’s victories included a contract to provide EC120s to the U.S. Customs and Border Patrol and EC145s to the U.S. Army.

The disparity in R&D funding is portentous for the future, since both China and India, the most populous nations, want to expand their rotorcraft markets to take full advantage of the aircraft type’s unique capabilities and lesser infrastructure requirements relative to those of fixed-wing fleets. They will come to U.S. or European manufacturers to do that. European manufacturers have made major advances in both China and India in the last few years.

After it introduced the Alouette 2, Aerospatiale predecessor Sud-Est quickly proved the capability of the airframe-engine combination by breaking the world helicopter altitude record. It entered production in 1956 in a five-seat version and became a highly popular helicopter.

Bell’s Jet Ranger, first flew in January 1966 and was FAA type-certificated in October of that year. It also was highly popular for offshore oil and other duties and became, with its variants, one of the most successful commercial helicopters. The five-seat Model 206A was powered by a 317-shp Allison 250 C18.

By 1968, Bell was projecting that the growing penetration of the helicopter market by newer, turbine-powered aircraft could lead to annual sales of $200 million within five years, compared to $58 million in 1967.

As evidence of the turbine’s acceptance, Garrett-AiResearch fitted a TSE36-1 220-shp engine on a Hughes 269A in 1967 and Enstrom Helicopter was intrigued enough to order a production quantity for its F-28A in 1968. The 150-200-hp range was the only one remaining that hadn’t been taken over by turbines.

At the time, there were nearly 2,000 civil helicopters flying in the United States, 85 percent of which were powered by piston engines in the 150-250-hp range. The U.S. Army had 800 piston-powered primary trainers in its fleet or on order.

Turbines offered comparable power at one-fourth the weight of a piston engine, although fuel consumption could be considerably higher. But the trade-off was worth it for more and more operators.

By 1971, the Los Angeles Police Dept. concluded "jet-powered helicopters would not only be economical for regular police patrols," we reported, "but would provide several important advantages."

These included better response time and the ability to cover a larger response area. That led the department to adopt an all-turbine patrol fleet for its Air Support Div. in March 1975, with 10 Bell 206Bs.

The breakthrough into the world of single-pilot IFR represented "the removal of one of the last major barriers to realizing the full potential of commercial helicopters," we noted.

We attributed that breakthrough to the team of Vought Helicopter and Sperry Flight Systems, which gained certification of the Gazelle as the first single-pilot, singe-engine helicopter.

The battle for approval of IFR operations in the United States was a protracted and trying one.

A 1972 test program at NASA’s Langley Research Center using a Vertol 107 had demonstrated that a helicopter could be flown entirely on instruments to a zero-zero landing, with no intervention by a pilot.

By that time, IFR operations were commonplace among fixed-wing commercial operations, but not so for their rotary-wing counterparts. This was due in large part to the FAA’s insistence that helicopters carry the full complement of IFR equipment that fixed-wing aircraft did.

In the mid-1970s, Petroleum Helicopters, Inc. protested that an aircraft the size of a Bell Helicopter 212 ought to be allowed to operate under IFR with two pilots, especially in light of all the avionics it was required to carry under Federal Aviation Regulations (FAR) Part 29. PHI’s pressure prompted the FAA to issue Special SFAR 29, which allowed two-pilot IFR operations under Part 29 without requiring the aircraft to have an IFR system installed under a supplemental type certificate.

PHI’s success motivated other operators, which flew aircraft certificated under FAR Part 27, to push the FAA for similar approval. National Mines Corp. of Lexington, Ky. led that charge, which culminated in the FAA extending SFAR 29 for two years under a -2 amendment to cover aircraft certificated under both Part 29 and Part 27.

By 1980, when that rule went into effect, there were 14 helicopter configurations certificated in the United States for IFR flight. These included the Aerospatiale SA341 Gazelle, SA360 Dauphin, and SA365C Dauphin 2; the Agusta A109A; the Bell 212 (in dual- and single-pilot configurations) and the Bell 206L and L-1 with a Collins autopilot, Boeing Vertol’s BO105C and Model 107, Sikorsky’s S-58T, S-61, and S-76.

To get a sense of how far the helicopter avionics field has come, consider a 1977 FAA survey of communications, navigation, and radar equipment in civil helicopters. It found that less than 31 percent of the civil fleet had any communications equipment (vs. nearly 18 percent for the general aviation fleet as a whole), roughly 25 percent carried transponders (vs. about 50 percent for the GA fleet), and practically no civil helicopter had area navigation capability or weather radar (98 percent lacked RNAV and 99.8 percent had no radar).

If rotorcraft were to penetrate into the corporate and similar markets, that would have to change.

"Expanded use of RNAV seems a natural progression," an executive at Bendix Avionics told R&W in 1979, "since helicopters are not limited to airport operations."

So much has been achieved in avionics advancements, we’ll focus on just one aspect.

In the early 1980s, a new acronym began creeping into the jargon of professional pilots — EFIS, for electronic flight instrument system. As we said in 1990, "it signaled an explosion of change."

What started out as an electronic version of the electromechanical attitude indicator and horizontal situation indicator, such as the Collins EFIS-86 and -74, have evolved into suites of highly capable tools for helping pilots manage their aircraft systems and their situational awareness. What one user said of such systems in 1990 is more true today: "These systems have such an abundance of capabilities that pilots need to take time with the handbooks to learn how to use them."

Among the latest iteration of the EFIS is Chelton Flight Systems FlightLogic, which provides basic navigation cues, but also integrates terrain awareness and warning and "highway-in-the-sky" situational awareness capabilities for the pilot.

Another by-product of general advances in computing capability that has benefited rotary- and fixed-wing aviators alike is the full authority digital engine controller (FADEC). This device automated the monitoring of critical limits on engines, improved the management of fuel consumption and engine performance, and increased the safety of flight operations.

The FADEC is a computer that receives signals from sensors on the engine and in the fuel system and applies a logic laid out by engine designers to optimize the powerplant’s performance. It schedules fuel consumption, records start parameters, prevents overtemps, and may abort a start to prevent damage to the engine. In emergency conditions, it can give the pilot all the power available from a good engine.

Pilot training has been a great beneficiary of computing advances, which have made full-motion simulators more capable and effective devices and improved the value of instruction that can be done in fixed-base flight training devices (for instance, by generating much more realistic visual scenes and cues). They’ve also given instructors more capabilities. Aerosimulators of Belgium, for example, markets a flight training device that tracks a trainee’s eye movements inside and outside the cockpit, giving the instructor a precise track of his scan.

The HAA 1967 convention that marked the birth of R&W was marred by a tragedy when an Alouette 2 on a demonstration flight crashed into a mountain at 7,500-ft. elevation, killing two of the three people on board. Our pages are replete through the years with recognition that steps needed to be taken to improve helicopter safety in general and that of emergency medical service and offshore operations in particular.

Recent efforts in the United States to reverse EMS accident rates mirror ones undertaken in the mid-1970s and mid-1980s. The efforts have slowly taken route and spurred the development of terrain awareness and warning systems and, in the case of offshore operations, more survivable aircraft designs. Today, offshore operators are taking the lead in safety efforts, driven by their customers to acquire more capable aircraft, enhance the communications and navigation information available to their crews, and provide those crews with more in-depth and focused levels of training.

Highlights of Manufacturer Milestones Since 1967

1967: First flight of the Sud-Aviation (Aerospatiale) Gazelle prototype, a five-seat helicopter. Originally designed to meet a French army requirement for an observation helicopter, the Gazelle was the result of research to develop a more modern version of the Alouette 2, the helicopter that helped launch the turbine era... Lockheed’s AH-56A compound helicopter makes its first flight.

1968: Hughes begins delivery of the Hughes 500 series... A new Bell JetRanger air ambulance makes its public debut at the Indianapolis Speedway during the Indy 500.

1969: The U.S. Army cancels the Lockheed AH-56A Cheyenne compound helicopter program... The U.S. Army/Bell YH-40 research compound helicopter becomes the first rotorcraft to exceed 300 mph. It achieves a level-flight speed of 274 kt.

1970: Sud-Aviation becomes Société Nationale Industrielle Aerospatiale (SNIAS) by merging with French Nord Aviation and SEREB. In 1984, SNIAS begins operating under the name Aerospatiale... Kamov’s Ka-26 debuts at a Western event, appearing at the Hanover, West Gemany air show.

1971: The MBB BO105 receives FAA certification in April, the first such certification of a German helicopter... Sikorsky tests a new rotor system called the advancing blade concept in NASA’s Ames Research Center wind tunnel in California.

1972: Jean Boulet sets the world record for helicopter altitude with a SA315B Lama, reaching 12,422 m (40,810 ft). The record still stands... Lockheed’s AH-56A Cheyenne compound helicopter is again killed by the U.S. Army.

1973: Industry veteran Frank Robinson founds Robinson Helicopter Co.... Igor Sikorsky dies on Oct. 26 at the age of 83.

1975: Agusta A109 receives FAA certification. Known for its speed and performance, the A109 was the first light twin with retractable wheeled landing gear designed for the corporate VIP... Sikorsky’s YUH-60A Utility Tactical Transport Aircraft System, under development for the U.S. Army, makes its first flight... The Agusta A109A debuts at the NBAA show in New Orleans.

1976: Bell Helicopter is acquired by Textron... The Hughes 500D makes its first flight... Aerospatiale unveils the new single-turbine AS350.

1977: Bell XV-15 tilt rotor research aircraft takes first flight in May.

1977: The Sikorsky S-76 makes its first flight in March. Designed to carry as many as 12 passengers for offshore oil transport, the S-76 also is targeted at the corporate and VIP markets. In the early 1980s, the S-76 claimed several world records for point-to-point travel between Boston and New York City

1979: U.S. Coast Guard awards contract for short-range recovery helicopters to Aerospatiale. The contract for the HH-65A Dolphin marks the first time a non-U.S. helicopter manufacturer receives a government contract.

1979: Sikorsky shuts down S-62 and S-64 production lines. In 1992, Erickson buys the rights to the S-64 Type Certificate.

1979: F. Lee Bailey sells his interest in Enstrom Helicopter Corp., which he bought in 1970. Under his tenure, Enstrom developed the F-280C, which was later named by FORTUNE Magazine as one of the 25 best factory-made products in the United States.

1980: European Helicopter Industries (E.H. Industries) is formed by Westland Helicopters and Agusta SpA to produce a large helicopter for both military and civil markets. The result is the three-engine EH101.

1981: First flight of a NOTAR system-equipped helicopter, developed by Hughes Helicopter, takes place in December.

1981: Hiller Aviation Inc. buys rights to the five-place FH-1100, which was first introduced in 1965 for the military,, from Fairchild Industries and begins production for the commercial market.

1982: Boeing Vertol delivers the first production CH-47D Chinook to the U.S. Army.

1983: Hughes Helicopters sells rights to the Model 300 to Schweizer Aircraft Corp., bringing that company into the helicopter market for the first time... Bell Helicopter and Boeing Vertol submit joint proposal for Bell-Boeing Tilt-Rotor for the Pentagon’s JVX program, precursor to the V-22... The Westland WG-30 receives FAA certification and begins operations for Los Angeles’ AirSpur airline.

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