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Rotorcraft Pioneers - Volume 2 - Frank N. Piasecki

Posted 14 years 27 days ago ago by Admin


By Brad McNally - Frank Nicolas Piasecki was born in Philadelphia on October 24, 1919. From a young age he was fascinated with aviation and spent his spare time building models and reading aviation magazines. When he was seven years old his father paid for him to go flying with a barnstormer and he got his first ride in an airplane. In high school he was president of his school’s aero club and was able to gain an introduction into the Philadelphia aviation industry that few people his age could acquire. In 1936, at the age of seventeen, he was able get a ride in a Kellett KD-1 Autogiro (Spencer, 1998). This experience peaked Frank Piasecki’s lifelong interest in rotary wing flight. After graduating from high school he worked several entry level jobs at the Kellett Aircraft Corporation and the Aero Service Corporation. It was at the Aero Service Corporation where he was encouraged to attend engineering school. He started at the University of Pennsylvania’s Towne School of Engineering majoring in mechanical engineering but switched to New York University’s Guggenheim School of Aeronautics to finish his degree in aeronautical engineering (Spencer). While at the Guggenheim School he took a graduate level class in rotary wing flight which increased his interest in helicopters. 
After graduation he returned to the Philadelphia aviation industry working as a junior engineer for the Platt-Lepage Aircraft Company. While at Platt-Lepage he worked closely with noted aeronautical engineer Elliot Daland who would later join forces with Piasecki and play a significant role in developing several models of Piasecki helicopters (Brandt & Davies, 2007). Frank Piasecki then worked as an aerodynamicist for Budd Manufacturing. In 1940, while working at Budd Manufacturing he organized a group of his former engineering classmates at the University of Pennsylvania into the PV Engineering Forum. The “P” stood for Piasecki and the “V” stood for Venzie, as in Harold Venzie, a member of the forum and one of his classmates. This group was commissioned as an informal engineering collaboration that intended to develop products for commercial applications. Within its membership there was tremendous engineering, managerial and skilled trade talent (Brandt & Davies). Frank Piasecki’s excitement for the helicopter was so great and his belief in the group so strong that he persuaded the rest of the members to design and build their own model. The group faced a tall task as there had only been one successful American helicopter up to that time and it had been designed, built and flown by Igor Sikorsky and his team. The Sikorsky team had much greater resources and more fixed wing aircraft experience than the PV Engineering Forum did. In truth they had hardly any resources and very little fixed wing aircraft experience outside of Elliot Daland who Frank Piasecki had persuaded to join the group. This was but a minor hurdle in the mind of Frank Piasecki and it makes what the PV Engineering Forum was about to do even more extraordinary.
The team set about designing its helicopter. For the first year there were no paid employees, the members of the Forum worked nights and weekends designing and testing new ideas. The original helicopter plan was to the build the PV-1. This helicopter would have a main rotor, but in place of the tail rotor there would be a ducted fan to counteract torque (Spenser, 1998). This idea had a lot of merit and showed the tremendous foresight of Frank Piasecki and his group as it was a precursor to today’s NOTAR systems. However it was complicated and the forum members decided to shelve the PV-1 in order to develop the PV-2 which would be a tail rotor configured helicopter. The PV-2 was not without its own challenges, not the least of which was finding parts and pieces that could be bought with the meager budget that was available to build it. Frank Piasecki was as resourceful as he was determined and so it was that he and his team found parts ranging from a scrap fixed wing fuselage to a freewheeling clutch from a Studebaker to allow for autorotation in case of an engine failure. The PV-2’s Franklin engine was one of the few things that was bought new. Led by Frank Piasecki’s keen understanding of aerodynamics, the forum members developed a unique method to dynamically balance the rotor blades. Up until that time rotor blades had only been balanced statically allowing them to weigh the same but not giving them the same center of gravity. By dynamically balancing the blades they all had both the same weight and the same center of gravity. This dynamic balancing along with the unique blade design, developed by Piasecki and Daland, gave the PV-2 remarkable stability even in high winds which was something that had not been accomplished in a helicopter up to that time. This would be an important feature in future designs as it allowed scaling up the size of the blades for larger helicopters. On April 11, 1943 with Frank Piasecki at the controls, the PV-2 successfully lifted off of the ground for the first time making it only the second American helicopter to do so. Thus began a long line of successful Piasecki helicopters and the first of many test flights for Frank Piasecki. At the time of the PV-2’s first flight he had only 14 hours as a pilot, all in fixed wing aircraft (Spenser). In October of 1943 Frank Piasecki flew the PV-2 in front of a crowd of military and government officials at National Airport in Washington, DC in an effort to interest them in the helicopter and the PV Engineering Forum. It was one of the most important days of his life and largely due to his outstanding piloting ability it was a success. After the demonstration concluded a Civil Aviation Authority representative presented Frank Piasecki with his helicopter license, the first ever issued to someone without a fixed wing license.
The demonstration at National Airport put the PV Engineering Forum on the map. In 1944, the forum received a Navy contract on behalf of the Coast Guard to construct a transport helicopter. Successfully completing this task would be as difficult as building their first helicopter. To that point helicopters had little utility and were barely able to lift their own weight and that of the pilot. It was here that Frank Piasecki would leave his greatest mark on the history of the helicopter. There were many disbelievers who thought that a helicopter could not possibly be built that would be large enough or powerful enough to be used for transport purposes. Frank Piasecki accepted this challenge knowing full well that failure would set the helicopter back years if not decades but that success would propel it forward an equal amount. He chose a tandem rotor configuration knowing that two main rotors could cancel out each other’s torque effect and greatly increase lifting ability by eliminating the power requirement of a tail rotor. Thirteen months later, in March of 1945, with Frank Piasecki at the controls, the XHRP-X Dogship became the first successful tandem rotor helicopter (Frank N. Piasecki, n.d.). Frank Piasecki and his team had succeeded. The XHRP-X was capable of carrying three times the payload of any other helicopter, could carry 10 men excluding pilots and reached speeds of up to 110 mph. The tandem rotor design also eliminated some significant center of gravity problems prevalent in the single main rotor helicopters of the day. As World War II ended so did much of the U.S. Navy funding that was being put into helicopter development. In order to bring in private backing for the company Frank Piasecki was forced to turn over control. The PV Engineering Forum was reorganized into the Piasecki Helicopter Corporation in 1946. Frank Piasecki continued with the company as President and Chairman of the Board of Directors (Frank N. Piasecki). With new financial backing in place many improved tandem rotor versions followed including the XHRP-1 and XHRP-2 Flying Banana. The tandem rotor design became increasingly popular and starting in 1948, 339 XHJP/XHUP/H-25 models were delivered to the U.S. Army, U.S., Canadian and French Navies. The XHUP-2 was the first production helicopter with an autopilot permitting IFR and hands off flight (Helicopters, n.d.). The H-21 was arguably Piasecki Helicopter Corporation’s most successful design. It was developed for the U.S. Air Force and improved on the X-HRP2. With a slightly larger rotor head and more powerful engine the gross weight more than doubled from 7255 pounds to 14,700 pounds (Helicopters). Over 700 of these aircraft were produced for the U.S. and foreign militaries. It was used extensively by the French in the Algerian War and by the U.S. in the beginning of the war in Vietnam. In 1953, U.S. Air Force H-21s set world records for speed, 146.7 mph, and altitude, 22,110 feet. In 1956, a U.S. Army H-21 using in-flight refueling crossed the county non-stop in a record 37 hrs (Helicopters). On the next line of tandem rotor helicopters the Piasecki Helicopter Corporation scored more firsts and significantly pushed helicopter development forward once again. The first prototype YH-16 was developed for the U.S. Air Force and became the world’s first twin engine helicopter. The second prototype, the YH-16A, was the world’s first twin turbine helicopter. It first flew in 1953 and at the time was the world’s largest helicopter. It had a fuselage the size of most large airliners at the time and could carry up to 40 troops or three light vehicles with a range of 230 miles and a max speed of 146 mph (Helicopters). This would be the last major tandem rotor design built during Frank Piasecki’s time at Piasecki Helicopter Corporation. He left the company in 1955 following disagreements with the major shareholder, Laurance Rockefeller, over the use of profits for research and development. Today the Piasecki Helicopter Corporation is part of Boeing Rotorcraft Systems. The popular CH-46 Sea Knight and CH-47 Chinook tandem rotor helicopter models used extensively by the U.S. Armed Forces are direct descendents of the XHRP-X. 
Helicopters had come a long way since the PV-2 first flew in 1943, but Frank Piasecki wasn’t done yet. In the mid 1950s, following his departure from Piasecki Helicopter Corporation, Frank Piasecki and some of the other original founders of Piasecki Helicopter Corporation founded a new company called Piasecki Aircraft Corporation or PiAC. Starting with the PA-59K Flying Geep in the late 1950’s, PiAC began developing a series of aerial vehicles for the U.S. Army. The Flying Geep used two piston engine powered horizontal ducted rotors and was successfully flown in and out of ground effect at speeds up to 75 mph. It could also land and be driven like a car. Two later models, the PA-59N Sea Jeep and the PA-59H Air Jeep II were turbine powered versions with increased power. The Sea Jeep was successfully flown over water and operated from a ship at altitudes of up to 220 feet (Geeps, n.d.). Frank Piasecki’s incredible vision also led him into compound helicopter technology in the 1960’s.  In 1962, PiAC flew the world’s first shaft driven compound helicopter, the 16H-1 Pathfinder. This aircraft combined the vertical flight capability of the helicopter with the higher speed of fixed wing aircraft. To do this a wing was added to unload the rotor in forward flight. A tail-mounted ducted propeller with adjustable rudder vanes, also called a Ring-Tail, replaced the tail rotor to provide forward thrust during high speed operation and anti-torque during hovering and low speed operations. The 16H-1 reached speeds of up to 170 mph. An improved version, the 16H-1A Pathfinder II, first flew in 1965 and reached speeds of up to 225 mph (Compound Helicopters, n.d.). Currently PiAC is involved in several U.S. Army projects. One project is flight demonstrating a second generation Ring-Tail called a Vectored Thrust Ducted Propeller or VTDP on the X-49A. The X-49A, also known as the Speedhawk, is a U.S. Navy Seahawk helicopter that has been modified with lifting wings and has had the tail rotor replaced by a VTDP. This compound helicopter was first successfully flown in 2007 and the modifications allowed the helicopter to fly 50 percent faster, twice as far, with greater maneuverability, reduced vibration and fatigue loads, improved reliability and reduced life cycle costs (X-49A “Speedhawk”, n.d.). Two other PiAC Army projects focus on UAVs. The Future Combat System Unmanned Aerial Vehicle Project involves an autonomous UAV capable of taking off and landing on a ground vehicle. In 2006, as part of this project, PiAC completed the world’s first autonomous autogyro flight with its Air Guard UAV (Piasecki Completes World’s First Autonomous Autogyro Flight, 2006). Another PiAC Army UAV project is the Taurais, which is a UAV capable of being launched from a wing or bomb bay. Frank Piasekci passed away in 2008 at the age of 88, but Piasecki Aircraft Corporation continues today as a leading developer of vertical takeoff and landing technology. Two of Frank Piasecki’s children, John W. Piasecki (President and CEO) and Fred W. Piasecki (Chairman of the Board and Chief Technology Officer) are actively involved in the business which is still located in the Philadelphia area.
Frank Piasecki’s legacy is one of tremendous determination, vision, and entrepreneurial spirit. His belief in the abilities of the many talented people that he surrounded himself with enabled him to achieve some remarkable accomplishments. His extraordinary determination was a key ingredient in his team designing and building the second successful North American helicopter and accelerating the pace of helicopter development in the 1940s and 1950s. His incredible vision allowed him to pursue the heavy lift helicopter. The advancements his company made in the heavy lift arena proved to many disbelievers that a practical and useful helicopter capable of transporting large loads of people and cargo was possible. His entrepreneurial spirit founded two companies that still exist today. The heavy lift portion of Boeing Rotorcraft Systems continues to be a worldwide leader in heavy lift helicopters and Piasecki Aircraft Corporation continues to work on the cutting edge of rotary wing flight in unmanned aerial vehicle and compound helicopter technology. Over the course of his lifetime Frank Piasecki was awarded 24 patents for his revolutionary work (Frank N. Piasecki, n.d.). For his ground-breaking achievements and longevity in the rotorcraft industry he received many honors and awards including the Smithsonian Air and Space Museum’s Lifetime Achievement Award in 2005, the National Medal of Technology present by President Reagan in 1986 and the 1954 Mendel Medal for outstanding scientific work. He is also a member of the Army Aviation, National Aviation and Helicopter Foundation International Hall of Fame. Frank Piasecki’s career as a designer, builder and pilot of rotary wing aircraft spanned nearly 70 years from the infancy of the helicopter in the 40s to some of the most advanced work in hybrid helicopter designs in the 21st century, making him a true Rotorcraft Pioneer.           
Brandt, R. J., & Davies, W. J. (2007). The Piasecki H-21 Helicopter. North America: Trafford.
Compound Helicopters. (n.d.) Piasecki Aircraft Corporation Website Heritage of Innovation Tab. Retrieved January, 15 2010, from http://www.piasecki.com/
Frank N. Piasecki. (n.d.). Piasecki Aircraft Corporation Website. Retrieved August, 18 2009, from http://www.piasecki.com/
Geeps. (n.d.) Piasecki Aircraft Corporation Website Heritage of Innovation Tab. Retrieved January, 15 2010, from http://www.piasecki.com/
Helicopters. (n.d.). Piasecki Aircraft Corporation Website Heritage of Innovation Tab. Retrieved January, 15 2010, from http://www.piasecki.com/
Piasecki Completes World’s First Autonomous Autogyro Flight. (July, 2006). Piasecki Aircraft Corporation Website. Retrieved January, 16, 2010, from http://www. jasonthibeault.com/piasecki/pdfs/AirGuardCompletes1stAutonomousFlight.pdf
Spenser, J. P. (1998). Whirlybirds: A History of the U.S. Helicopter Pioneers. Seattle, WA: University of Washington Press
X-49A “Speedhawk”, (n.d.). Piasecki Aircraft Corporation Website. Retrieved January, 14 2010, from http://www.piasecki.com/