According to the Museum’s website (which also provides technical specifications):

The HH-43 was developed from the earlier HOK-1 for the U.S. Navy and Marine Corps. The first prototype flew in 1953. The intermeshing rotor configuration eliminated the need for a tail rotor. Also, by substituting a gas turbine engine for the reciprocating engine of the earlier model, and mounting it above the cabin, it was possible to carry up to 10 passengers in the space previously occupied by the engine.

The Navy had used helicopters for “Plane Guard” duties during carrier operations to pick up flyers who ditched or crashed. The “Huskie,” however, was the first helicopter to be used by the U.S. Air Force for that purpose. The HH-43 saw use in Vietnam, known informally as “Pedros” because of their radio call signals, with Air Rescue and Recovery Squadrons. From 1966 to 1970, the Huskies saved more lives in combat, 888, than any other USAF helicopter.

Equipped with a fire suppression kit, Huskies on rescue alert could be airborne in about a minute and could reach crash sites before ground vehicles arrived. By spreading foam and by using its powerful downdraft it could open a path for rescuers to reach crash victims.

The HH-43 was retired from active service in the early 1970’s, replaced by the Sikorsky HH-3 Jolly Green Giant.

Taken with a Sony RX-100 M3.

According to the Museum’s website (which also provides technical specifications):

THIS AIRCRAFT IS ON LOAN FROM THE NATIONAL NAVAL AVIATION MUSEUM, PENSACOLA, FLORIDA

The Seasprite is a ship-based helicopter with anti-submarine and anti-surface threat capability, including over-the-horizon targeting. It was also used for search and rescue missions. It was designed to be a fast, all-weather utility craft for the U.S. Navy.

Taken with a Sony RX100 M3.

According to the Museum’s website (which also provides technical specifications):

Gift of Frank J. Pacheco

Designed and developed by Sikorsky Aircraft and converted to this configuration by Doman Helicopters, this U.S. Army Air Force R-6A is one of about 200 produced by Nash-Kelvinator just before the end of World War II.

The conversion is the work of Glidden Doman who worked on the development of the R-6 at Sikorsky. Doman Helicopters began working in Stratford in 1946, designing a system meant to simplify the rotor head, reduce stress on the rotor blades, and greatly reduce forces on the controls. The Air Force Propeller Laboratory aided the effort by loaning this aircraft, and after the Doman-funded first flights in 1947, contracted a flight test stress measurement program which confirmed the success of the new rotor system.

This hingeless rotor design that was developed is driven by a constant-velocity universal joint making it free to tilt relative to the fuselage without causing any stress or vibratory effects. The blades, increased in diameter by two feet from the standard R-6, are so well balanced that fingertip control forces were enjoyed without any servos. The hingeless rotor concept was adopted by many designers some 40 years later.

Taken with a Sony RX100 M3.

According to the Museum’s website (which also provides technical specifications):

Gift of William Gallagher, Nancy C. Gallagher, T. Scott Gallagher and Nancy Gallagher Jones

Built in Danbury, Connecticut by Doman Helicopters Inc., this helicopter was FAA certificated and delivered to the U. S. Army in 1955. The design evolved in consultation with Army pilots from the ‘MASH’ medical evacuation activity after they flew a previous Doman experimental helicopter that had a very similar layout. It was the second of two aircraft, designated YH-31s, that were purchased by the Army and it was flown extensively at Fort Rucker and by the Navy at the Patuxent River Test Center. Then it was repurchased from the Navy and used by Doman in its commercial efforts.

It features the sealed, rigid and hingeless rotor system pioneered by Doman, and is powered by a 400 hp supercharged Lycoming engine that is cooled by exhaust ejectors rather than a fan. That feature increased its useful payload by about 800 pounds.

A total of only three craft were built, and this is the only surviving example.

Taken with a Sony RX-100 M3.

According to the Museum’s website (which also provides technical specifications):

Courtesy of the United States Coast Guard

The HH-52/S-62 was the forerunner of a new generation of turbocopters and was the world’s first true amphibious helicopter. It was designed to operate from land, water, snow, ice, mud, swamp and tundra. This helicopter was one of 99 similar craft built for the U.S. Coast Guard with its role as a search and rescue and general utility craft. The “Seaguard” was a workhorse for the Coast Guard and they were based on Coast Guard cutters, icebreakers and air stations until they were retired in 1989. HH-52’s were credited with saving over 15,000 souls on their 25 years of service. This aircraft was stationed at the Detroit Coast Guard Air Station.

As the S-62A, it was the first turbine rotorcraft to be granted FAA approval for commercial use.

Taken with a Sony RX-100 M3.