Vertol V-43 / Piasecki H-21C (c/n WG7, formerly 83+07 of Heeresfliegertruppe / the German Army Aviation Corps), exhibited at Hubschraubermuseum Bückeburg (Bückeburg Helicopter Museum), June 2023.
In January of 1944, the American aviation engineer and rotorcraft pioneer, Frank N. Piasecki, signed a contract with the US Navy to develop a tandem-rotor transport helicopter.
On 7th March 1945, the rotorcraft, officially designated by Piasecki as PV-3 but commonly dubbed the Dog Ship, successfully performed its maiden flight. Within two years, the helicopter entered service with the US Navy, the Marine Corps and the US Coast Guard, where it was known as HRP-1 Rescuer (or just Harp).
The rotorcraft was the first from Piasecki´s series of successful tandem-rotor helicopters, known as ´flying bananas´, due to their characteristic silhouette. In 1949, an upgraded variant of the HRP-1 was developed and entered into service with the US Coast Guard as HRP-2 (company designation PV-17). At the same time, a smaller tandem-rotor helicopter known as HUP-1 (PV-18) was designed by Piasecki and delivered to the US Navy and the US Army. Depending on the branch of the US armed forces the rotorcraft was in service with, the aircraft was designated the Retriever, H-25 Army Mule or UH-25.
The fourth tandem-rotor design was initially developed in response to the US Air Force request for a high-altitude, Arctic rescue helicopter. Piasecki won the competition with his YH-21 prototype, able to carry up to fourteen troops or twelve stretchers, and designed to operate in cold weather environment with temperatures as low as -54°C.
On 11th April 1952, the YH-21 performed its maiden flight. The new rotorcraft was powered by single, Wright R-1820-103 Cyclone nine-cylinder radial engine, generating 1150 hp. The helicopter was equipped with two fully articulated, three-bladed counter-rotating rotors, and fixed, tricycle landing gear with additional floats to ensure the all-terrain operational capability.
Shortly after its maiden flight, the helicopter was ordered by the USAF and officially designated H-21 Work Horse (also spelled as Workhorse). Initially, the rotorcraft was produced in two different configurations – a search-and-rescue variant and an assault helicopter.
In the next few years, a few upgraded versions of the helicopter were developed. The first significant modernization was designated the H-21B and equipped with an upgraded 1425 hp Wright engine, autopilot and external tanks. The helicopter was able to carry up to twenty soldiers.
Initially, the H-21 helicopters entered service with the USAF and the Royal Canadian Air Force, and – due to their Arctic capabilities – were used at the Distant Early Warning Line radar installations in the Great North, Alaska, Greenland and Iceland.
The H-21 was also acquired by the French and Japanese armed forces, the Swedish Navy (designated there as Piasecki HkP1), the Army Air Corps of the West German Army, the US Army (designated H-21C Shawnee) and the Zairean Air Force.
Additionally, commercial variants of the rotorcraft were also designed and known as Model 44A, B and C.
Production of the H-21 was ceased in 1959. Until that time, more than 700 examples of the helicopter were manufactured.
Regrettably, the time when the H-21 entered the market was not very successful for Frank Piasecki himself. In 1956, he lost confidence among the major shareholders of the company and was forced to leave the enterprise he founded. Soon after, Piasecki Aircraft Corporation was re-branded Vertol. Finally, in 1960, the company was acquired by Boeing.
The German army aviation ordered thirty-two examples of the H-21C variant (later re-designated Vertol V-43). The helicopters were license-manufactured in Germany by Weser-Flugzeugbau GmbH in Bremen, and the first example was delivered to the Army Aviation Corps between 1957 and 1960.
In the German service, the V-43 was operated by the army aviation units based at Fritzlar, Celle, Bückeburg and Mending. In addition, one example of the civilian V-44B variant was also in service with the Bundeswehr, acquired from the Belgian airline Sabena. The German V-43s remained operational until the early 1970s, when they were retired and replaced by Sikorsky CH-53 Sea Stallion.
A few German V-43s are now being exhibited in aviation museums across the country. One of them, the example with WG7 construction number – which was in service with Heeresfliegertruppe as PA+202, QF+461, PX+336 and 8307 – is now part of rotorcraft exhibition at Hubschraubermuseum Bückeburg, the biggest helicopter museum in Europe (more information about the museum and its collection can be found in our article from August of 2023 – An incredible journey through rotorcraft history, from an aerial screw to the Mars Helicopter – Bückeburg Helicopter Museum).
