Frank Piasecki, inventor of the big twin-rotor helicopter, the Chinook and the Sea knight, died on 11 February 2008 after a brief illness. He was one of the last surviving American aviation pioneers from an earlier era.

In 1943, he became the second American to build and fly a helicopter, after Igor Sikorsky's first flight in 1941. He was born 24 October 1919, in Lansdowne, Delaware County, of Polish parentage.

At age 88, Piasecki was chief executive of his firm Piasecki Aircraft Corp.

Piasecki and his wife, Vivian, raised seven children. Daughter Nicole Piasecki is president of Boeing's operations in Japan. Two sons, Frederick and John, are vice presidents of his company and are carrying on his work.

Piasecki was an accomplished violinist and a gifted amateur photographer.

The US Army's Chinook as well as the US Navy's Sea Knight are now built by the Boeing Co's Rotorcraft Division.

Chuck Allen, chief of Boeing Rotorcraft, called Piasecki "a visionary and an amazing designer. . . . He will always be remembered as a pillar of American aerospace history. His daring and courageous approach to vertical flight inspired years of advancements."
 
When Piasecki fell ill his chief test pilot, Steven A Schellberg, was in the air completing a key phase of testing of his latest invention - a ducted fan to replace a helicopter's vertical tail rotor that will increase speed and manoeuvrability.

"He's the father of Boeing Rotorcraft. We would not be where we are without his mind and entrepreneurial skills," J. Patrick Donnelly, Boeing's director of advanced rotorcraft, said in an October interview. "He struggles physically, but we still have conversations with him about our work. His mind is very fertile."

His friends and others described Piasecki as a demanding boss who refrained from holding grudges and even thanking those who stood up to him.

The Navy has only now begun replacing his Sea Knight with the V-22 Osprey, which takes off like a helicopter, then tilts its rotors to fly like an airplane.

But new models of the Army Chinook have received fresh transport and special operations missions and are also being pitched to the Air Force for search-and-rescue missions.

Boeing says Piasecki's creation, which was one of the most heavily used pieces of machinery in the Vietnam War of the 1960s, will keep flying well beyond 2030.

Piasecki gave up control of his first company to get funds to build the big factory in Morton, Delaware County, to mass-produce the tandem-rotor helicopter. Its name was changed from Piasecki Helicopter Co to Vertol Aircraft Corp., which Boeing acquired in 1960.

In 1955, Piasecki formed his current company, Piasecki Aircraft Corp, through which he went on to achieve a long list of firsts in expanding the capabilities of helicopters.

His new Speed Hawk seeks to change helicopter flight in several ways. While conventional helicopters achieve speed by tilting forward and counter the rotation of the horizontal main rotor with a small vertical tail rotor, both of which creates drag, Piasecki's ducted fan pushes the aircraft forward, thanks to fins that direct thrust to counter the main rotor's torque and keep it level.

The innovation gives it more speed and range without any loss of manoeuvrability.