• 02 Mar 2021 01:36 PM
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Piasecki Aircraft: Carrying on the Spirit of Innovation

By Robert W. Moorman
Vertiflite, March/April 2021

Frank Piasecki’s sons have picked up where their father left off in developing next-generation rotorcraft technology.

[Image on the Top: The Piasecki PA-890 electric slowed-rotor winged compound helicopter. (All images via Piasecki)]

Fred Piasecki, Chair and CTO (left), and John Piasecki, President and CEO.

Among the many luminaries in rotorcraft history, the name Frank Piasecki stands out alongside that of Igor Sikorsky. While Sikorsky flew America’s first successful helicopter in 1939, young Piasecki was close on his heels. In 1943, he became the second designer to fly a successful helicopter in the US (see sidebar).

Today, Piasecki Aircraft Corporation (PiAC), based in Essington, Pennsylvania, is led by two of Frank’s sons: Frederick Weyerhaeuser Piasecki, Chairman and Chief Technology Officer, and John Weyerhaeuser Piasecki, President and Chief Executive Officer.

While the iconic Piasecki Sr. is a hard act to follow, the company today is in good hands. “Given that military platforms tend to last half a century or more, hope for innovation depends on independent design houses that aren’t wedded to existing, long-term production programs,” observed Richard Aboulafia, Vice President of Analysis at Teal Group Corp. “Piasecki is the most important and experienced of these.”

Piasecki has a number of noteworthy programs under development for the US military and commercial customers.

PA-890 eVTOL
The PA-890 eVTOL all-electric vertical takeoff and landing (eVTOL) slowed-rotor winged compound helicopter is designed for multiple roles, including emergency medical services (EMS), on-demand mobility (ODM), on-demand logistics (ODL), personnel air transport and other commercial applications. Compared to a conventional helicopter, Piasecki claims the PA-890 eVTOL will reduce direct operations costs (DOCs) by 50%, emit zero emissions compared to a fossil-fuel-powered turbine aircraft and reduce noise significantly, which should enable public acceptance of rotorcraft in urban areas.

Noteworthy is the PA-890’s large, single-main rotor, swiveling tail rotor providing anti-torque and yaw control, and a variable incidence wing that tilts up to 90% to minimize download for better hovering. To transition to forward flight, the wing rotates to a horizontal position, “providing lift to offload the rotor, [while] the tail rotor swivels to provide efficient forward propulsion,” according to the company’s website. CEO John Piasecki said, “We adopted the slowed-rotor compound helicopter because it provides a great combination of good hover and forward flight performance that meets our customers’ needs and is the simplest and safest path to delivering that capability at the lowest cost.”

The PA-890 has both civil and military applications, with a projected range of 200 nm (370 km) and seating for five, including flight crew.

But the promise of lower DOCs is the chief selling point of the PA-890. “Reducing operating costs is the single most important goal for our customers,” said Piasecki. “Yes, creating a more environmentally sound aircraft is a noteworthy goal. But adoption will be significantly faster if you can reduce the DOCs.”

The overall configuration of the customer-driven PA-890 is being refined. Piasecki said, “We have entered into a number of confidential customer agreements, which provide a framework for us to collaborate on the product development to make sure that the aircraft has a viable market once it is certified.”

Regarding airworthiness certification by the US Federal Aviation Administration (FAA), “We have a clear path to FAA certification using the well-established Part 27 standard,” said Piasecki. “Our schedule is not yet public, but development plans call for flight testing within the next three years, and certification will follow on the FAA's timeline.”

ARES
The Aerial Reconfigurable Embedded System (ARES), an unmanned aerial vehicle (UAV) with a tilting twin ducted-fan configuration, is another noteworthy Piasecki program. ARES was a Defense Advanced Research Projects Agency (DARPA) project initiated in 2012 with Lockheed Martin as the prime contractor (responsible for developing the flight control software) and PiAC as lead subcontractor for air vehicle development. ARES successfully completed 30 hours of ground testing and was cleared for hover flight in 2019. However, funds were exhausted before getting to flight, leading DARPA and the US Marine Corps (USMC) to close the contract.

“Following extensive component, integrated system and ground testing of the ARES aircraft, DARPA and the USMC have decided to end further investment in the program due to significant cost growth and delays,” the Department of Defense (DoD) agency stated. “The program was a research effort that addressed technical risks for a future vertical takeoff and landing concept that would transition to fixed-wing forward flight. The investment provided risk reduction to potential future DoD programs by developing flight control software to manage complex configurations, and maturing a unique ducted fan approach to propulsion."

Undaunted, Piasecki Aircraft now runs the program and is continuing development with its own funding, plus Army and Air Force support. “We are developing the flight control system to get the aircraft to first flight with a proof-of-concept demonstrator,” said Piasecki. ARES could provide huge support for ground forces with its modular multi-mission capability, he said. PiAC’s approach to get to flight focuses on implementing fly-by-wire capabilities at a substantially lower cost, leveraging a modified commercial-off-the-shelf (COTS) approach. The CEO said a major announcement on the ARES program would soon be forthcoming.

ARES has a small landing footprint to enable shipboard and expeditionary operations in remote and rugged terrain. The UAV is designed to provide multi-mission command, control, communications, computers and intelligence (C4I); intelligence, surveillance and reconnaissance (ISR); and combat logistics support for combat operations.

ADAPT
In 2007–08, PiAC flew its X-49 "SpeedHawk" high-speed compound helicopter, a YSH-60 Seahawk airframe with wings and the company’s vectored thrust ducted propeller (VTDP), which was based on extensive flight testing the company had conducted in the 1960s. Piasecki accumulated 86 flight hours in 79 flights during the initial flight testing (see “X2, X3, S-97 and X-49: The Battle of the Compounds is Joined,” Vertiflite, Winter 2010). 

 

All testing was restricted to the standard Seahawk’s flight manual limitation of 180 kt (335 km/h), but the X-49A demonstrated up to a 42% increased speed at equivalent power, and as much as 50% reduction in vibration and fatigue loads. All contract technical objectives were achieved, the CEO said.

An important aspect of the X-49A program that has continued, Piasecki said, is the development of Adaptive Digital Automated Pilotage Technology (ADAPT) flight control technology. ADAPT is aimed at reducing pilot workload and providing automated trim and maneuver optimization, and damage-tolerant controls that can be reconfigured to keep the aircraft operating safely. The advanced technology can drive down operating costs and help the aircraft operate more efficiently. The program is currently developing control algorithms and architecture to allow application to a broad range of advanced VTOL configurations, which are being evaluated in iterative series of piloted simulation experiments and scaled flight tests. After validation in full-scale flight tests, the technology will be postured to transition into future programs for the Army and other military services, as well as commercial applications, like eVTOL.

Future Challenges
In a recent interview, Piasecki gave his big picture views on various topics involving the rotorcraft industry. On where the industry is headed, he said, “There is a convergence of three major developments. One is the advanced VTOL vehicle configurations that promise to raise the forward flight efficiency of vertical lift vehicles substantially. Another is the emergence of alternative energy sources to power rotorcraft. The third is the evolution of advanced flight controls, automation, sensing and cyber technologies that facilitate the implementation of these advanced systems into a broader network.

“Many of the missions [that] vertical lift is being asked to perform are straining the capabilities of conventional helicopters,” he said, such as expanding missions from the Army’s 200-km (108-nm) radius out to 400 km (216 nm) into hazardous near-earth environments. The ongoing development of advanced vehicle configurations and flight control autonomy, coupled with sensing/perception technologies will reduce pilot workload and have a synergistic effect on survivability and safety in military and civil sectors, he said.

Piasecki offered another cautionary note on flying headlong into the future: As exciting as the vision of eVTOL air taxis is, “that market does not exist presently,” he said. “We have a lot of work to do to ensure that the vehicle succeeds, which has nothing to do with the vehicle’s capability. The challenge lies with the airspace, regulatory obstacles and other factors.” VFS has also identified these issues as some of the key challenges.

On the related question of whether the FAA will allow for autonomous vertical flight aircraft operations, Piasecki said, “It won’t happen overnight. I think FAA’s crawl, walk, run approach toward autonomous vehicles is essential.”

The viability of autonomous aircraft “is not a technical question,” he said. “It’s a culture question. Society has to accept autonomous vehicles for them to succeed.” In time, autonomous vehicles will be approved for operation in defined corridors to minimize risks. One way to boost public confidence in autonomous operations, offered Piasecki, is to have a pilot onboard to serve in a supervisory and safety capacity.

On important advances not typically covered by the consumer press, Piasecki said: “Batteries have made tremendous progress in terms of capabilities, weight and energy density, but they are not there yet, and the time to achieve required levels of performance is an uncertainty that has to be managed.”

The interview turned to the complex subject of producing new aircraft in an era of rising materials and production costs. The biggest challenge to designing, certifying and mass-producing the next-generation fixed- and rotor-wing aircraft is having sufficient capital, patience and time. Piasecki was reflective when asked if it was possible to shorten the time it takes to bring a new aircraft to market, from concept to first flight to certification to delivery.

“The question you’re asking is fundamental and the biggest barrier to infusion of new technology and competition into the aerospace industry,” he said, adding that it takes a minimum of six years to develop new rotorcraft/VTOL — or double that time. “The Leonardo Helicopters AW609 tiltrotor has been in development for 25 years,” he said. It was originally unveiled in 1996 as the Bell Boeing BB609 and is expected to finally be certificated this year.

Piasecki added his views about the developer’s role in the development of new aircraft. The ideal design group, he said, should be small, agile and adaptive, with the ability to burn down risks efficiently while producing a viable solution.

“As part of any solution, you need to think about transitioning from design into a practical application,” he said. “We pride ourselves on practical innovation. We have the ability to innovate by creatively using proven technology, design and processes that are of inherently lower risk, in new ways that add value… What makes a good R&D [research and development] organization does not necessarily make for a good production entity.”

A Strong Heritage
On its website, PiAC describes itself as an “ideas company with a heritage of practical innovation in rotorcraft and UAV development.” While rotorcraft technology has advanced exponentially since Frank Piasecki founded the company, the basic goals of providing forward-looking rotorcraft designs have not. Like their pater familias before them, the two sons keep their focus on the future.

Delaware Valley, which encompasses areas of southeastern Pennsylvania, southern New Jersey, Delaware and the eastern shore of Maryland, is the cradle of rotary-wing development in the US. Piasecki Aircraft is a principal tenant in the Valley, along with Boeing, Leonardo’s AgustaWestland Philadelphia Company, and scores of suppliers.

Bob Beggs, co-founder and trustee of the American Helicopter Museum & Education Center in West Chester, Pennsylvania (and chair of the VFS History Committee), put the past and future of Piasecki Aircraft in perspective: “Frank Piasecki once said, ‘There’s a lot more to do. The future is bright. It’s yours. Be there!’ And I believe that John and Fred are taking Piasecki Aircraft into the future just as their father intended.”

Snapshot of Frank Piasecki

Born in Philadelphia in 1919, the son of an immigrant Polish tailor, Frank Nicholas Piasecki began his career in his teens, working for the Kellett Autogiro Corporation.

By 20, Piasecki had studied mechanical engineering at the University of Pennsylvania before earning a degree in aeronautical engineering from New York University’s Guggenheim School of Aeronautics, where he studied under rotary-wing aeronautics pioneer Dr. Alexander Klemin (it was Piasecki who instigated the VFS KIemin Award in 1951). Following graduation, Piasecki became a controls engineer for the Platt-LePage Aircraft Company, working on what would become the XR-1.

At the same time, Piasecki and his friend Harold Venzie formed the P-V Engineering Forum in 1941. Working out of a garage, they built the PV-2, a single-rotor helicopter with a conventional tail rotor. Piasecki flew it himself on April 11, 1943, becoming the second successful American helicopter designer. Later that year, he demonstrated the small helicopter for military leaders at National Airport in Washington, DC.

As his reputation grew, so too did Piasecki’s interest in larger helicopters. He designed the world’s first successful tandem rotor helicopter, the XHRP-X, which could lift larger loads. Supported by a US Navy contract, the XHRP-X made its first flight in March 1945, with the company founder again at the controls. The XHRP-X was the precursor to a long line of tandem rotor helicopters that became part of Boeing’s rotorcraft product line in 1960, including the Marines’ CH-46 Sea Knight and larger Army CH-47 Chinook, still in service today. Both aircraft played critical roles for the US since launched during the Vietnam War in the mid-1960s.

Piasecki’s later innovations included the Pathfinder ring-tail, high-speed compound helicopter (forerunner of the X-49) and the Sea Bat Unmanned Helicopter Drone. He was the recipient of 24 patents.

With his innovations came notoriety and awards. Piasecki was a founding member of the-then American Helicopter Society (now VFS) and its seventh president (1950–1951). He was the recipient of the 1980 VFS Klemin Award, given for notable achievement in rotary-wing aeronautics. In 1986, Piasecki received the National Medal of Technology from President Ronald Reagan and, in 2005, Piasecki was awarded the National Air and Space Museum’s “Trophy for Lifetime Achievement.”

Milestones

• 1940: Piasecki starts Piasecki-Venzie Engineering Forum
• 1943: First Flight of the PV-2
• 1945: First flight of the XHRP-X
• 1946: Company renamed Piasecki Helicopter Corporation
• 1947: First flight of the Piasecki HRP-1
• 1955: Piasecki Aircraft Corporation (PiAC) founded
• 1956: Frank Piasecki forced out of Piasecki Helicopter Corp, which is renamed Vertol
• 1958: First flight of the Piasecki VZ-8P AirGeep 1
• 1960: Boeing acquires Vertol
• 1962: First flight of the Piasecki 16H Pathfinder high-speed compound helicopter
• 1965: First flight of the Piasecki 16H-1A Pathfinder II high-speed compound helicopter
• 1986: First flight of the Piasecki Heli-Stat heavy-lift aircraft
• 2005: Company selected by US Army for two Future Combat Systems (FCS) UAV systems
• 2006: The FCS Class III UAV system contract is awarded to Piasecki, which flew the world’s first autonomous autogyro as part of that program. Also that year, the US Navy’s Naval Air Systems Command awards demonstration contract to Piasecki to validate the “Vectored Thrust Ducted Propeller” system
• 2007: First flight of the Piasecki X-49 compound
• 2008: Frank Piasecki passes
• 2016: Piasecki/Vertol/Boeing “Morton” site recognized as a VFS Vertical Flight Heritage site

About the Author
Robert W. Moorman is a freelance writer specializing in various facets of the fixed-wing and rotary-wing air transportation business. With more than 30 years of experience, his writing clients include several of the leading aviation magazines targeting the civil and military markets. He can be reached at rwmassoc325@gmail.com.