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HO3S Dragonfly

The HO3S-1 was the first Navy helicopter to replace fixed wing aircraft operating with the fleet. From the 1920s on, seaplanes were the aircraft carried aboard battleships and cruisers. In 1948 Sikorsky's newest production helicopter began to "supplement" the Curtiss SC-1s on board fleet cruisers. Before long, supplement became replace. By late 1949, the HO3S-1 had taken over; the seaplanes were gone.

Based on WW II experience with its initial R-4 (HNS-1) and the later R-5 (HO2S-1) and R-6 (HOS-1) helicopters, Sikorsky developed its first S models, S-51s, for commercial use in 1946. These were based on the R-5s, but were four-place rather than two-place, with a bench seat for three passengers behind the pilot's seat. The P&W R-985 Wasp Jr. was retained for power; the general configuration was similar but many improvements were incorporated.

The HOS-1 was a precursor to the HO3S-1, the first helicopter delivered to the Marine Corps in February 1948. The HO3S-1 helicopter was a minor modification of the Sikorsky commercial model S-51, which was, in turn, a larger modification of the Navy's H02S-1-a version in itself of the Air Force's R-5. A Wasp Jr. R-985-AN-5 450-horsepower engine turned a single three-bladed articulated rotor and torque compensating tail rotor. The blades of the main rotor could be folded back so that the helicopter could be transported by a cargo aircraft virtually anywhere. The aircraft could be equipped with dual controls and had accommodations for a pilot and three passengers. Originally, the helicopter weighed 3,788 pounds empty with a maximum take-off weight limited to 4,988 pounds. The model had a tricycle landing gear and differed from the standard commercial model by having an oil dilution system-needed for operation in cold weather-installed in addition to provisions for one 50-gallon fuel tank and a 300-pound capacity rescue hoist. Because of the limited instrumentation in the H03S, the aircraft was restricted to day flying, visual flight rules (VFR), and a maxium air-speed of 90 knots.

In September 1946 with Operation High Jump (the first postwar Antarctic expedition) coming up, four S-51s were ordered, to be used from High Jump ships. Only minor changes were made, principally the incorporation of an external auxiliary fuel tank and some coldweather modifications.

By January 1947, two had been ditched at sea but their overall effectiveness justified ordering two replacements in February. In April, procurement of 20 more was authorized for general fleet use, with changes to meet fleet requirements. Blade folding, an externally mounted hoist, and Navy radio gear were to be incorporated in production. Before deliveries began, 20 more were ordered. Ultimately, a total of 91 were delivered for Navy and Marine Corps use.

By the end of 1947 deliveries were being made to squadrons on both coasts and, following training, shipboard operations were under way in 1948. The concept of established squadrons furnishing one or two-plane detachments to the operating ships was soon standard. Later, as more were accepted, the H03Ss were evaluated by the Navy for plane guard duty, mail delivery, personnel transfer, and also as training aircraft.

Although the Marine Corps was hopeful of having helicopters operating in HMX-1 in January 1948, the first two Sikorsky H03S-ls did not arrive from VX-3 to the newly formed Marine Helicopter Squadron One at Quantico until 9 February 1948. February 9, 1948 marked the delivery of the first helicopters to the Marine Corps and that delivery changed the face of the Corps forever. The development of the helicopter coupled with that of the amphibian tractor is what made the Marine Corps what it is today. Helicopters gave Marines the capability for air mobility and assault from the sea. Ever since their introduction to the Marine Corps, helicopters have played an invaluable role in the mission of the Corps. The first helicopters were intended for utility use.

Three more reached the squadron by the end of the month having been ferried directly from the Stratford plant. As indicated in the CNO's Aviation Plan No. 57, Supplement No. 3, the full complement of six H03S-ls was not expected to be reached until 01 July 1949. In the same aviation plan dated 06 April 1947, it was indicated that only six HRPs were to be in the squadron's inventory by the same date. This announcement brought great disappointment to Marine Corps planners as they were expecting to have the complete complement of 12 transport helicopters by the July 1949 date.

The Marines' new H03Ss were primarily intended for utility use; however, the squadron at Quantico was not too concerned with the official mission description listed in the BuAer publications. The aircraft were first put to use in the training of the pilots and mechanics as an additional four officers and nine enlisted men had joined the squadron during January . The first mission of an operational nature, exclusive of training, was on 24 February when an H03S was used to lead a salvage party to an amphibious jeep ("Weasel") that had become mired in a creek.

While the H03S-1 retained its observation designation, its fleet use was almost entirely in the utility role, with early recognition of its value as a plane guard for carrier operations. By 1950, fleet use of the helicopter was well established and improved models were being developed.

With the outbreak of war in Korea, the HO3S-1 assumed a new role as a combat rescue helicopter. The observation squadron, VMO-6, was expanded in early July 1950 for deployment as a composite squadron by the addition of four HO3S-ls. With the addition of the helicopters, VMO-6 became the first squadron of its kind. The squadron sailed from San Diego, on 14 July 1950 on board the USS Badoeng Strait(CVE-116) bound for Korea. While newer helicopters were coming on the scene, Marine H03S-1s (and the Air Force H-s series "twins") successfully undertook the rescue of both downed aircrew and injured ground personnel. Although the HO3S-ls were performing a valuable service and were practically indispensible, the fact remained that they were not a suitable military helicopter due to their deficiencies in payload, range, flight instrumentation, and communication equipment.

Because of the deficiencies in the H03S-1, an improved prototype, the XHO3S-2, was developed during 1950. However, many of its improvements (such as all-metal, constantchord rotor blades replacing the tapered wood and metal ones) were derived from newer models, and production turned to these, with no more HO3Ss being built. Even so, the HO3Ss soldiered on with the fleet through most of 1954, and the last in shore-based service was not stricken until 1957.

Each of the HO3S-1G was fitted with a rescue hoist and the Coast Guard's Rotary Wing Development Unit based out of Elizabeth City, NC, experimented with a number of innovations that enhanced the helicopters' versatility, including a rescue basket and emergency flotation bags that were fitted around the landing gear. The size of the rescue basket, however, and the limited room within the HO3S's cabin precluded its use until the introduction of a larger helicopter. The team also developed a "Wobble Plate Stabilizer" which consisted of a small wing mounted on and behind the non-rotating portion of the wobble plate and served primarily as a means of trimming the inherent control forces and damping any displacements occurring during flight.

Based out of Elizabeth City and later New Orleans, among other air stations, the HO3S-1G demonstrated the helicopter's utility in search and rescue operations, eclipsing the role of fixed-wing amphibious aircraft. CDR Erickson, the Coast Guard's premiere supporter of rotary-winged aviation, along with his Rotary Wing Development Unit, used both the HO3S and the HTL-1 in many rescues that proved the value of this new type of aircraft for Coast Guard operations. Although their emphasis was on search and rescue, Erickson also demonstrated the helicopter's usefulness in combined cutter and helicopter operations, guiding ships through ice fields, conducting law enforcement patrols and the transportation of personnel and equipment.

This pioneering aircraft proved the value of rotary-winged aircraft to the service and even set a world record. On 6 April 1949, a Coast Guard HO3S-1G, CG No. 234, piloted by the ubiquitous LT Graham, completed the longest unescorted helicopter ferry flight on record. The flight took place from Elizabeth City, North Carolina to Port Angeles, Washington, via San Diego, California. The total distance of the flight was 3,750 miles and took 10 and a half days to complete and involved a total flight time of 57.6 hours. Steward was accompanied by Aviation Machinist Mate Robert R. McAuliff.

While the H03S-1 retained its observation designation, its fleet use was almost entirely in the utility role, with early recognition of its value as a plane guard for carrier operations. By 1950, fleet use of the helicopter was well established and improved models were being developed.

With the outbreak of war in Korea, the HO3S-1 assumed a new role as a combat rescue helicopter. While newer helicopters were coming on the scene, Marine H03S-1s (and the Air Force H-s series "twins") successfully undertook the rescue of both downed aircrew and injured ground personnel.

Because of the deficiencies in the H03S-1, an improved prototype, the XHO3S-2, was developed during 1950. However, many of its improvements (such as all-metal, constantchord rotor blades replacing the tapered wood and metal ones) were derived from newer models, and production turned to these, with no more HO3Ss being built. Even so, the HO3Ss soldiered on with the fleet through most of 1954, and the last in shore-based service was not stricken until 1957.



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