7 March 1945

Flying without it’s fabric covering, the XHRP’s tubular steel structure is clearly visible. (Piasecki Aircraft Corporation)

7 March 1945: At Morton Grove, Pennsylvania, Frank Nicholas Piasecki, founder (along with Harold Venzie) of the P–V Engineering Forum, made the first flight of the PV-3, a prototype for the first successful tandem rotor helicopter. The United States Navy designated the new helicopter XHRP-X. Two additional prototypes, designated XHRP-1, Bu. Nos. 37968 and 37969, were ordered. The original aircraft, a proof-of-concept aircraft, made its final flight in May.

Because of the arrangement of the fuselage, which allowed vertical clearance between the fore and aft rotors, the helicopter was popularly known as “the Flying Banana.” Internally, like many engineering test aircraft, the XHRP-X was called “the dog ship.”

Frank Piasecki was the first pilot to be licensed by the C.A.A. as a helicopter pilot (who had not previously held an airplane license).

Frank Nicholas Piasecki with the PV-3 (XHRP-X) prototype. (Piasecki Aircraft Corporation)

The PV-3 was designed to be flown by two pilots and be capable of carrying 10 passengers. The fuselage was 47 feet, 2 inches (14.376 meters) long. Each of the three-bladed rotors were 41 feet (12.497 meters) in diameter. The overall height was 13 feet, 11 inches (4.242 meters). The helicopter had an empty weight of 4,279 pounds (1,941 kilograms), and gross weight of 6,420 pounds (2,912 kilograms). The helicopter had fixed tricycle landing gear with castering wheels.

The PV-3 was powered by an air-cooled, supercharged, 971.930-cubic-inch displacement (15.927 liter) Continental-built Wright Whirlwind (R-975), a nine-cylinder radial engine rated at 450 horsepower, mounted in the rear fuselage. A transmission transferred power from the engine to two driveshafts running along the top of the fuselage, to remote gearboxes, which in turn, drove the two main rotors. The rotors turned in opposite directions with each canceling the torque effect of the other. No tail (anti-torque) rotor was required, as in single-rotor helicopters. Without a tail rotor, which can absorb as much as 30% of the engines’ power, all the power can be put directly into lift and thrust, making the aircraft much more efficient.

The helicopter had a cruise speed of 100 miles per hour (161 kilometers per hour) and maximum speed of 110 miles per hour (177 kilometers per hour). Its range was 300 miles (483 kilometers).

P–V Engineering Forum PV-3 proof-of-concept prototype in out-of-ground-effect hover. (Piasecki Aircraft Corporation)

The XHRP-1 was ordered into production as the HRP-1 and HRP 2. They were operated by the U.S. Marine Corps and U.S. Coast Guard. Including the prototypes, 28 of the helicopters were built.

The “Flying Banana” concept was later seen in the Piasecki H-21 Work-Horse, which first flew in 1952.

Piasecki CH-21B Workhorse, 51-15857, at the National Museum of the United States Air Force. (U.S. Air Force)

The Boeing CH-47F Chinook, which is currently in production, is a direct descendant of Frank Piasecki’s PV-3.

The 100th Boeing CH-47F Chinook was delivered to the United States Army in August 2013. (Boeing)

© 2019, Bryan R. Swopes

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7 thoughts on “7 March 1945

  1. Hi Brian, thank you for putting these daily archive posts together – it’s the highlight of my morning to view these. Awesome job, please know that your efforts are appreciated by a great many folks. Joel

  2. I concur with Joel. This site is my first read of the day. And I very much appreciate the accuracy and completeness. I can only imagine the amount of research it takes to produce this content.

        1. Thank you, Jerry. It’s too late to write an article today, but perhaps I could back-publish it. I appreciate your bringing it to my attention.

  3. Mr. Swopes, I thought you might want to see this from the New York Times. I found it while trying to pin down a date for Piasecki’s helicopter license.

    The short version is, Piasecki’s helicopter license was a not a first. But it was a first for someone who did not already own a fixed-wing license.

    It is stated in the correction at the bottom.

    https://www.nytimes.com/2008/02/15/business/15piasecki.html

    “A correction was made on March 4, 2008: An obituary on Feb. 15 about Frank Piasecki, a pioneer in helicopter design, misstated the significance of the helicopter license he was issued by the federal government on Oct. 20, 1943, when he arrived in Washington to demonstrate his first helicopter. It was the first helicopter license issued to someone who did not already have a license to fly a fixed-wing aircraft; it was not the first government-issued helicopter license. (C. L. Morris, the chief test pilot for Igor Sikorsky, another helicopter pioneer, had received the first helicopter license, in March 1942.)”

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