Rotary Aircraft History
Leonardo da Vinci, the great Italian artist-inventor, is accredited with having given, in the sixteenth century, the fundamental idea of the helicopter. He had drawn in his note-book models of helicopters which had air-screw or flying windmill revolving in a horizontal plane. He used the Greek word helix, meaning spiral or twist in connection with the idea of flight.
Leonarda Da Vinci conceived the idea of 'airscrew', as he called it, in 1480. However, the time for human flight came in late 1700s when the Montgolfier Brothers began going around France in balloons. After the balloon experiment, two winged aircraft captured the imagination of the dreamers. Among these were the ornithopters and the gliders. An ornithopter had wings that flapped like those of a bird. While ornithopters and gliders were receiving attention, other talented inventors were developing helicopter. Even though the original inspiration for helicopter came from the Chinese top, the development of the screw propeller for marine propulsion undoubtedly gave many helicopter designers a more current starting point. Helicopters, just as ornithopters, became successful small-scale models.
One of the early experimenters, Pontoon Amecout coined the word 'helicopter' from two Greek words- 'heliko' meaning 'spiral' and 'pteron' meaning 'wing'.
The initial development of helicopter was fraught with numerous technical problems with no viable solutions within the reach of available technology. Helicopters were viewed as objects of curiosity with very little practical use. However, the realisation of the ubiquitous nature of helicopters and the great strides in technology has seen the production and utilisation of helicopters increasing by leaps and bounds.
All the early models of helicopters were devoid of two essentials : a true understanding of rotor dynamics (incomplete until recently) and the availability of a powerful engine. The breakthrough came at the end of the nineteenth century with the invention of the internal combustion engine. It was then that they found the first of many great control problems- torque-the effect produced by the rotor to force the fuselage to rotate in the opposite direction of the engine.
The beginning of the twentieth century saw the designers experimenting and resolving many of the problems that appeared with each advancement. In 1907 the Frenchman Breguet made a 1000 1b rectangular helicopter which attained an altitude of 15 feet and flew a distance of 64 feet. This gyroplane flew for one minute on August 24, 1907 (some sources say September 29, 1907) in what is generally accepted as the first vertical flight. On November 13, 1907, the French pioneer, Paul Cornu lifted a twin rotored helicopter into air without any assistance from ground, for a few seconds. Another French, Etienne Oehmichen became the first pioneer to fly a helicopter in a closed circuit in 1924. It was a historic flight of seven minutes and forty seconds. Advances continued slowly but steadily.
The first successful helicopters made were the Focke-Wulf FW-61 which appeared in Germany in 1936. The first practical rotary wing aircraft developed in the United States was the Sikorsky Model VS-300, designed by Russian-born Igor Sikorsky in the late 1930s. In 1941, the Army ordered a similar model of the Sikorsky helicopter for use in observation, communication, and rescue work. Having proved their worth during World War II, rotary wing aircraft continued to develop at an accelerated pace throughout the 1940s and 1950s.
In spite of delays the Marine Corps had certainly not been relegated to a second rate competitor in the helicopter field, but, rather, was the leader. Each service desired the helicopter for performing missions peculiar to its own needs. The development of amphibious vertical assault techniques made the Marine Corps the leader in its own area of endeavor, as the vertical envelopment operation entailed practically all aspects of helicopter applications.
The main interest of the Navy, as it had been since 1943, was in obtaining a helicopter with sufficient hovering capability to perform antisubmarine warfare missions. Of secondary importance to the Navy was the need for the utility helicopter, which for the time was being filled by the Piasecki HUP-1.
The Army Field Forces had used small helicopters since 1947. Army helicopters were used for tasks similar to those performed by the "jeep." The Army too saw the advantages of larger lift helicopters for use in the movement of heavy artillery pieces, bridging material, and the tactical movement of combat troops.
After the Armed Services Unification Act of 1947, Air Force interest in helicopters was limited to the pursuit of a helicopter suitable for search and rescue services. Like the Air Force, the Coast Guard was also interested in a search and rescue helicopter and would most likely adopt one of the Navy' s designs to meet its requirement.
Throughout this period each service was required to settle for far less lift performance from helicopters than planners desired. The list of experimental helicopters on both the drawing boards and in the various stages of development was exceptionally long, with most of the experimental machines supposedly capable of satisfying the most demanding specification of the military planners. In the interlude, though, this meant that the existing helicopters had to fill roles for which they were not designed. They served as an "interim" machine for rescue, ASW, assault, liaison, observation, or for whatever tasks were necessary and could be performed .
|H-27||Piasecki||initially the designation for the second YH-16 w/T-38 turbine engines, redesignated YH-16A prior to the first flight in 1955.|
|H-28||Hughes||Designation assigned to the improved H-17 Model M-190-4A. None ever built.|
|H-29||McDonnell||Designation assigned to the 2-seat version of the H-20. The project was cancelled.|
|H-33||Bell||Original Army designation given to the XV-3 Convertiplane.|
|H-35||McDonnell||Original Army designation given to XV-1. Reserved for Navy use and then cancelled. Designation never utilized.|
|H-36||Bell?||Reserved for Navy use and then cancelled. Designation later assigned to a classified project, LONG EARS, a/c# 59-5926.|
|H-38||Reserved for Navy use and then cancelled. Designation later assigned to a classified project, SHORT TAIL.|
|H-40||Bell||The production models designated UH-1.|
|H-42||Hughes||Model 269, the YHO-2HU later the TH-55A Osage for the Army.|
|H-44||Reserved for Navy use and then cancelled. Designation later assigned to a classified project, BIG TOM.|
|H-45||secret Air Force FTD (Foreign Technology Division) project STEP CHILD.|
|H-49||Boeing-Vertol||briefly allocated in 1962 to a USAF Model 107 helicopter, then changed to XCH-46B.|
|H-69||skipped and will not be assigned.|
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