Sikorsky H-5

https://en.wikipedia.org/wiki/Sikorsky_H-5

The Sikorsky H-5, (initially designated R-5 and also known as S-48, S-51 and by
company designation VS-327) was a helicopter built by Sikorsky Aircraft
Corporation.

It was used by the United States Air Force, and its predecessor, the United
States Army Air Forces, as well as the United States Navy and United States
Coast Guard (with the designations HO2S and HO3S). It was also used by the
United States Post Office Department.

In December 1946, an agreement was signed between the British company Westland
Aircraft and Sikorsky to produce a British version of the H-5, to be
manufactured under license in Britain as the Westland-Sikorsky WS-51 Dragonfly.
By the time production ceased in 1951, more than 300 examples of all types of
the H-5 had been built.

The H-5 was originally built by Sikorsky as its model S-48, designated as the
R-5 by the United States Army Air Forces. It was designed to provide a
helicopter having greater useful load, endurance, speed, and service ceiling
than the Sikorsky R-4. The R-5 differed from the R-4 by having an increased
rotor diameter and a new, longer fuselage for two persons in tandem, though it
retained the R-4's tailwheel-type landing gear. Larger than the R-4 or the later
R-6, the R-5 was fitted with a more powerful Wasp Junior 450-hp radial engine,
and quickly proved itself the most successful of the three types. The first XR-5
of four ordered made its initial flight on 18 August 1943. In March 1944, the
Army Air Forces ordered 26 YR-5As for service testing, and in February 1945, the
first YR-5A was delivered. This order was followed by a production contract for
100 R-5s, outfitted with racks for two litters (stretchers), but only 34 were
actually delivered. Of these, fourteen were the R-5A, basically identical with
the YR-5A. The remaining twenty were built as the three-place R-5D, which had a
widened cabin with a two-place rear bench seat and a small nosewheel added to
the landing gear, and could be optionally fitted with a rescue hoist and an
auxiliary external fuel tank. Five of the service-test YR-5As were later
converted into dual-control YR-5Es. The United States Navy evaluated three R-5As
as the HO2S-1.

Several H-5Hs were converted in 1949 to a unique medical-evacuation role, with
casualty stretchers loaded sideways through blister-hatches on the side of the
fuselage. The back stretcher station was located just forward of the tail boom
and the main stretcher station was located behind the crew cabin. The forward
stretcher station could accommodate two casualties, who were accessible to the
medic in flight, while the back stretcher station handled only one, not
accessible to the medic during the flight. Very little information is known
about the operational use of this modification by the USAF, this being abandoned
shortly after tests in 1950.

The R-5 had been designated under the United States Army Air Forces system, a
series starting with R-1 and proceeding up to about R-16. In 1947 with the start
of the United States Air Force, there was a new system, and many aircraft, but
not all, were redesignated. The R-5 became the H-5. The United States Army broke
off with its own designation system in the 1950s, resulting in new designations
for its helicopter projects. In 1962 under the new tri-service system (see 1962
United States Tri-Service aircraft designation system), many navy and army
aircraft were given the low numbers. Under the 1962 system, the low H numbers
were given to new aircraft. For example, H-5 was given to the OH-5, a prototype
design which never entered Army service.


Role
Helicopter

Manufacturer
Sikorsky

First flight
18 September 1943

Introduction
February 1945

Retired
1957

Primary users
United States Air Force

United States Navy
United States Marine Corps


Produced
1944–1951

Number built
over 300

Developed from
Sikorsky R-4

Variants
Westland Dragonfly

During its service life, the H-5/HO3S-1 was used for utility, rescue, and mercy
missions throughout the world, including flights during Operation Highjump in
the Antarctic. While the extra power of the H-5 made it significantly more
useful than its R-4 and R-6 cousins, the H-5/HO3S-1 suffered, like most early
small tandem-seat single-rotor machines, from center of gravity problems. As a
matter of routine, the helicopter was equipped with two iron-bar weights – each
in a canvas case – one of 25 lb (11 kg) & one of 50 lb (23 kg). Flying with no
passengers, both weights were placed forward alongside the pilot. With three
passengers, both weights were normally placed in the baggage compartment.
However, in conditions of high ambient temperatures, which reduced lift due to
the lowered air density, all weights were jettisoned. If the weights could not
be recovered later, pilots on future missions were forced to utilize rocks or
other improvised weights next to the pilot after offloading three passengers, or
else travel at a very slow 25 knots (46 km/h; 29 mph).

The H-5/HO3S-1 gained its greatest fame during the Korean War when it was called
upon repeatedly to rescue United Nations pilots shot down behind enemy lines and
to evacuate wounded personnel from frontline areas. It was eventually replaced
in most roles by the H-19 Chickasaw. In 1957, the last H-5 and HO3S-1
helicopters were retired from active U.S. military service.

Specifications

General characteristics
Crew: two
Capacity: two stretchers in external panniers
Length: 57 ft 1 in (17.40 m)
Rotor diameter: 48 ft 0 in (14.63 m)
Height: 13 ft 0 in (3.96 m)
Disc area: 1,810 sq ft (168.2 m²)
Empty weight: 3,780 lb (1,718 kg)
Loaded weight: 4,825 lb (2,193 kg)
Powerplant: 1 × Pratt & Whitney R-985 Wasp Junior, 450 hp (335 kW)

Performance
Maximum speed: 92 knots (106 mph, 171 km/h)
Range: 313 nmi (360 mi, 580 km)
Service ceiling: 14,400 ft (4,390 m)

Climb to 10,000 ft (3,050 m): 15 min





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