|Year/Model:||1964 UH 34D|
|Power Plant:||1x Wright R-1820-84 radial engine, 1,525 hp|
|Rotar Diameter:||56 feet 0 inches|
|Length:||49 feet 9 inches|
|Height:||15 feet 11 inches|
|Gross Weight:||7,900 pounds (empty) 14,000 pounds (max with load)|
|Maximum Speed:||122 mph|
|Maximum Range:||215 miles|
|Service Ceiling:||9,500 feet|
|Crew:||2 plus 6,100 lbs|
|Status:||Static Display, Currently undergoing restoration|
|Owner:||Estrella Warbirds Museum|
Early development of the Sikorsky S-58 (H-34) helicopter was accomplished with company funds as a follow on for the S-55 (H-19) helicopter. It was twice as powerful as the S-55 and much more aerodynamic. It was marketed to the Navy and Marine Corps but the Navy chose the Bell HSL-1 helicopter and the Marines the S-56 (H-37) helicopter. Problems with both these programs led both customers back to Sikorsky to purchase over 1,000 S-58 helicopters in two configurations. The Navy Anti-Submarine Warfare (ASW) version SH-34J (HSS-1 and HSS-1N) was contracted for in June 1952. First flight was on March 8, 1954. A US Army order for the H-34A followed in 1955. Marines purchased a Utility version UH-34D (HUS-1) in 1957. During the following years, customers like the US Air Force, US Coast Guard, foreign militaries, and licensed production in France, Great Britain and Italy over 25 years swelled the number of S-58 Helicopters built to over 2,300 units.
The S-58 features a 56 foot 4 bladed main rotor and a 4 bladed tail rotor. Both main and tail rotor blades use the symmetrical NACA 0012 airfoil. The S-58 has a wind tunnel developed aerodynamic fuselage and a 4 bladed main rotor. Sikorsky chose a 4-blade rotor for the S-58 because it produced a lower blade loading compared to the 3-blade S-55 rotor and therefore would be able to fly faster before encountering blade stall. Another reason for the four blades was to reduce aircraft vibrations.
The S-58 (H-34) set a speed record of 141.9 mph on a 100 Kilometer closed course on July 12, 1956. Clam shell doors on the engine compartment allowed easy access for servicing as well as expediting engine changes. The all-metal fuselage utilized magnesium skins in certain areas as a weight saving measure. Corrosion and the fire hazard experienced with certain S-58 models discouraged further use of magnesium for airframe components by Sikorsky on subsequent models.
The conventional landing gear (main wheels in front, tail wheel in back) enhanced ground handling by greatly reducing the turning radius of the helicopter. The rear tail wheel also improved safety by making the tail wheel the first thing to hit the ground in a quick stop landing rather than the tail rotor blades. A manually folded main rotor and a folding pylon were provided to allow the helicopter to fit on aircraft carrier elevators.
The Navy SH-34J had dipping Doppler navigator, an AN/AQS-4/-5 dipping SONAR, and Automatic Stabilization Equipment (ASE), a helicopter autopilot system, which allowed the helicopter to achieve a hover and maintain position over the SONAR transducer without pilot assistance. The ASE equipment was a giant step forward for Anti-Submarine Warfare allowing missions at night and in low visibility conditions. Weapons carried included torpedoes (2), mines (2), or depth charges (2).
The Marine Corps and Army CH and UH-34 models carried 16 troops or 6 litters and a medical attendant. VH-34 models, operated by both the Army and the Marine Corps, were equipped with plush interiors, additional soundproofing, and air conditioning systems. Presidents Dwight Eisenhower and John Kennedy were transported in VH-34 helicopters. The Marine Corps took their UH-34D helicopters to Viet Nam in large quantities were they proved their worth as a tough and reliable machine.
The first flight of the S-58 was on March 8, 1954. Four prototype helicopters (XHSS-1) were built for testing. The first production SH-34G (HSS-1) flew on September 20, 1954. The SH-34G entered Navy service in August 1955. The first Army model CH-34A (H-34A) unit was operational in September 1955. The Marine model UH-34 D (HUS-1), a utility version of the S-58, entered service in February 1957.