Helicopter Hkp1 – The real ”banana”


A new way to fly

At the end of the Second World War (1939-1945) several manufacturers had started to work seriously on the development of helicopters. One of these was the Piasecki company that in 1949 showed off its H-21 ”Workhorse” to the US Air Force. This was a twin-rotor helicopter, a concept that the company had been working on since 1944. The peculiar appearance of these helicopters led to them being popularly called ”Flying Bananas”.

The H-21 was brought out as a rescue helicopter suitable for arctic climates, and this probably influenced how it operated in various areas of the world. It first flew in April 1952 and the first orders rapidly followed.

Piasecki’s design with two rotors turned out to exhibit several advantages, probably the greatest being the ability to lift heavy loads or carry many people. In 1956 the company changed its name to the Vertol Corporation. Vertol is a contraction of the terms Vertical Take off and Landing, which fits a helicopter company admirably. Boeing bought up the company in 1960, which resulted in the Boeing Vertol name, and the H-21’s new name became the Vertol 44.

A preserved U.S. Air Force H-21. Photo by Peter Langsdale.

The helicopter goes to war

Helicopters proved their worth during the Korean War from 1950 to 1953, mainly in the fields of transportation, rescue and carrying wounded. However the H-21 received its baptism by fire in 1956 as a result of the war in Algeria, where French troops used these helicopters in large numbers, not just for transport but also in battle. The H-21 was however considered by the French to be rather clumsy and vulnerable in its role as an attack helicopter, being better suited as a troop transport, protected by smaller helicopters which could carry out an initial attack before H-21s could land and disembark soldiers.

When the Vietnam War broke out the H-21 was also present, and demonstrated that it was not well suited to operation in tropical conditions, due to its having been developed for the cold arctic. In addition, it was relatively slow and both the crew and controls were very vulnerable to fire from ordinary hand-held weapons. Some of the American Army’s first casualties in what would become known as the Vietnam War occurred when an H-21 was shot down in July 1962. By 1965 all the CH-21 helicopters had been withdrawn from active service in Vietnam.


The predecessor

The H-21, or as it was called after its manufacturer had changed its name, the Vertol 44, would fly in many places and many different countries. Its heavy-lift capability and large transport capacity made it popular enough for over 700 to be built. Boeing Vertol therefore continued to develop new helicopters based on the twin tandem rotor design. The first was the CH46 Sea Knight (known in Sweden as the HKP 4) followed by the powerful CH47 Chinook that is still in production and has outlived many proposed replacements,

Both of these helicopters still clearly show traces of their origins with their predecessor and sometimes are also called ”banana helicopters”. Nevertheless, there is only one real ”Flying Banana”!