HH-53 Super Jolly Green Giant Vietnam

The US Air Force ordered 72 HH-53B and HH-53C variants for Search and Rescue units during the Vietnam War, and later developed the MH-53J Pave Low version for Special Operations missions.

The large green airframe of the HH-53B earned it the nickname "Super Jolly Green Giant". This name is a reference to the smaller HH-3E "Jolly Green Giant", a stretched variant of the H-3 Sea King, used in the Vietnam War for combat search-and-rescue (CSAR) operations. The US Air Force regarded their Sikorsky S-61R/HH-3E "Jolly Green Giant" long-range CSAR helicopters favorably and was interested in the more capable S-65/CH-53A. In 1966, the USAF awarded a contract to Sikorsky for development of a CSAR variant of the CH-53A.

The HH-53B, as it was designated, featured:
- A retractable in-flight refueling probe on the right side of the nose
- Spindle-shaped jettisonable external tanks with a capacity of 650 US gallons (2,461 L), fitted to the sponsons and braced by struts attached to the fuselage
- A rescue hoist above the right passenger door, capable of deploying a forest penetrator on 250 feet (76 m) of steel cable
- Armament of three pintle-mounted General Electric GAU-2/A 7.62 mm (.308 in) six-barreled Gatling-type machine guns, with one in a forward hatch on each side of the fuselage and one mounted on the tail ramp, with the gunner secured with a harness
- A total of 1,200 pounds (540 kg) of armor
- A Doppler navigation radar in the forward belly
- Early HH-53Bs featured T64-GE-3 turboshafts with 3,080 shaft horsepower (2,297 kW) each, but these engines were later upgraded to T64-GE-7 turboshafts with 3,925 shaft horsepower (2,927 kW). Five crew were standard, including a pilot, copilot, crew chief, and two pararescuemen.

The HH-53B was essentially an interim type, with production quickly moving on to the modestly improved Air Force HH-53C CSAR variant. The most visible difference between the HH-53B and HH-53C was that the HH-53C dispensed with the fuel-tank bracing struts. Experience with the HH-53B showed that the original tank was too big, adversely affecting performance when they were fully fueled, and so a smaller 450 US gal (1,703 L) tank was adopted in its place. Other changes included more armor and a more comprehensive suite of radios to improve communications with C-130 tankers, attack aircraft supporting CSAR actions, and aircrews awaiting rescue on the ground. The HH-53C was otherwise much like the HH-53B, with the more powerful T64-GE-7 engines.

A total of 44 HH-53Cs were built, with introduction to service in August 1968. Late in the war they were fitted with countermeasures pods to deal with heat-seeking missiles. As with the HH-53B, the HH-53C was also used for covert operations and snagging reentry capsules, as well as snagging reconnaissance drones. A few were assigned to support the Apollo space program, standing by to recover an Apollo capsule in case of a launchpad abort, though such an accident never happened.