The Grumman HU-16 Albatross is a twin-radial-engined, amphibious flying boat that was designed and produced by American aircraft manufacturer Grumman. Originally designated as the SA-16 in USAF service and the JR2F-1 and UF-1 in USN and USCG service, respectively, it was redesignated as the HU-16 in 1962.
It was operated by a wide range of air services, including the United States Air Force (USAF), United States Navy (USN), United States Coast Guard (USCG), and Royal Canadian Air Force (RCAF). It was most commonly operated as a search-and-rescue (SAR) aircraft. Even after its retirement by multiple US-based military services, the Albatross continued to be operated by the military services of several other countries. The last military operator of the type was the Hellenic Navy of Greece, which withdrew its last examples in 1995.
Design and development The Hu-16 Albatross has its origins in a requirement issued by the USN for a new amphibious utility aircraft. Among the performance criteria stipulated was the need for it operate from snow and ice by the use of removable skis. The Hu-16, which was an improvement of the preceding Grumman Mallard, was designed in response; it was capable of landing in the open ocean if operationally required. Its deep-V hull cross-section and keel length enable it to land in the open sea. The Albatross was designed for optimal seas, and could land in more severe conditions, but required jet-assisted takeoff (JATO or simply booster rockets) for takeoff in seas or greater. The Albatross initially carried an APS-31A radar in a pod on the left wing, but this position meant the fuselage obstructed the radar's ability to search to the right of the flying boat, thus it was repositioned to the nose on later SA-16As.
The HU-16 Albatross is a high-wing, amphibious, flying boat. For land operations, retractable landing gear was installed; the main gear retracted into a well in the side of the hull, which would flood during water operations. Most of this water would be forced out through a hole in the rear bulkhead by the acceleration forces generated during the takeoff run. The nose gear was twin-wheeled and free-castering, thus no nose-wheel steering was possible. The nose gear compartment was sealed from the hull and would also partially flood during water operations; this compartment could be visually inspected from the flight deck via a compact window. For lateral stability during water operations, the Hu-16 was provisioned with tip floats. The underside of the flying boat was constructed using round-head rivets, while the remainder of the hull used flush rivets, instead.
The original model of the HU-16 was powered by a pair of Wright R-1820-76 nine-cylinder, two-speed supercharged, radial engines, capable of producing up to 1,450 hp, that drove a three-bladed constant-speed propeller. These propellers were electrically controlled and hydraulically actuated, and had an integrated oil cooler within the hub dome. One advantage of this arrangement was that propeller control was available on engine start without needing to wait for engine oil to warm. Both to improve manoeuvrability while on the water and to shorten its landing run, the propellers with reversible; JATO apparatus was also optionally fitted, enabling the type to conduct a relatively rapid takeoff run. Differential engine power was needed to achieve directional control on the water, as the air rudder was not effective at slow speeds with no water rudder present. Differential braking was relatively troublesome to accomplish. The majority of fuel was contained in wing tanks, while additional fuel could be stored within the tip floats, although the latter could not hold much fuel without rendering the HU-16 unable to operate from the water due to decreased buoyancy. Wing racks were commonly fitted for the carriage of bombs or drop tanks. When fully fueled (including the use of drop tanks), the HU-16 could cover 3,000 miles, enabling nonstop flights between Alaska and Japan.
The HU-16 was furnished with a fully reversible flight-control system, which comprised a combination of cables, pulleys, and pushrods. The rudder could be hydraulically boosted, although this was not required for normal flight and was typically only active while performing takeoffs and landings; it could also relieve pedal forces during single-engine flight. Electrically actuated trim tabs were present on the elevators, rudder, and left aileron, while the right aileron was furnished with a fixed tab, instead. The elevator trim tabs were controlled and actuated independently for redundancy. The flaps were electrically controlled, hydraulically actuated, and hydraulically balanced.
Any Hu-16 could be outfitted with the Triphibian conversion kit, which involved the fitting of a hydraulically actuated skid below the keel of the hull, along with compact outrigger skids onto purpose-built mounting tubes fitted to the floats and reinforcement of the keel. When fitted, the flying boat could directly land on ice and snow in addition to runways and bodies of water. This kit was not the only means of preparing the Hu-16 for winter operations; several of the USN's fleet were structurally reinforced for such purpose.
On 24 October 1947, the first prototype performed its maiden flight; shortly thereafter, the USAF placed its own order for the type, initially designated SA-16A, to perform air-sea rescue operations. The type was originally intended solely for military service, hence civil certification for the original model was not pursued. During the mid-1950s, the improved SA-16B, which featured increased wingspan, larger ailerons, and bigger tail surfaces, was developed. In 1957, the first early-build model was converted to this configuration. Despite these improvements, the flying boat's speed and altitude limitations were viewed as limiting its usefulness by the late 1960s.
Proposed new build Amphibian Aerospace Industries in Darwin, Australia, acquired the type certificate for the Hu-16. In December 2021, the firm announced that it planned to commence manufacture of a new version of the HU-16, which was scheduled to commence in 2025. Designated the G-111T, it is planned to be fitted with modern avionics and powered by a pair of Pratt & Whitney PT6A-67F turboprop engines; several configurations would be developed for different roles, including passenger transport, cargo haulage, SAR, coastal surveillance, and aeromedical evacuation.
Operational history United States services
Most Albatrosses were used by the USAF, primarily in the SAR mission role and initially designated as SA-16. The USAF used the SA-16 extensively in Korea for combat rescue, earning a reputation as a rugged and seaworthy craft. Later, the redesignated HU-16B (long-wing variant) Albatross was used by the USAF Aerospace Rescue and Recovery Service and saw extensive combat service during the Vietnam War. In addition, a small number of Air National Guard air commando groups were equipped with HU-16s for covert infiltration and extraction of special forces from 1956 to 1971. Other examples of the HU-16 made their way into Air Force Reserve rescue and recovery units prior to its retirement from USAF service.
The USN also employed the HU-16C/D Albatross as an SAR aircraft from coastal naval air stations, both stateside and overseas. It was also employed as an operational support aircraft worldwide and for missions from the former Naval Air Station Agana, Guam, during the Vietnam War. Goodwill flights were also common to the surrounding Trust Territory of the Pacific Islands in the early 1970s. Open-water landings and water takeoff training using JATO was also conducted frequently by USN HU-16s from locations such as NAS Agana, Guam; Naval Station Guantanamo Bay, Cuba; NAS Barbers Point, Hawaii; NAS North Island, California, NAS Key West, Florida; NAS Jacksonville, Florida; and NAS Pensacola, Florida, among other locations.
In July 1952, an SA-16 from the 58th Air Rescue Squadron rescued 32 survivors of a British Douglas DC-3 that had crashed in the Mediterranean Sea. The pilot, Capt. Kendrick U. Reeves, later received the Cheney Award for his actions.
In October 1957, an SA-16B flew to a position 120 nautical miles south-southeast from Sardinia to pick up a F-100 pilot. After recovering the pilot, takeoff was determined to be impossible due to damage from the landing, and the aircraft taxied 45 nautical miles towards Bizerte, Tunisia, before being taken in tow by a French Navy corvette for the remainder of the trip. This incident set the USAF's record for the longest taxi time from water to dry land.
As part of the International Ice Patrol in 1958 and 1959, USCG UF-2Gs dropped Mk 35 and Mk 36 incendiary bombs on icebergs.
On 24 May 1962, a USAF SA-16 was launched to assist in the recovery of the Aurora 7 space capsule and astronaut Scott Carpenter. Despite arriving on scene ahead of two USN Sikorsky SH-3 Sea King helicopters, the Albatross was instructed not to land by the recovery force commander due to concerns over its ability to take off again in heavy seas. A minor controversy later arose over whether the decision was motivated by interservice rivalry.
In February 1964, a USAF HU-16B sent to retrieve the nose cone of a missile fired from Cape Kennedy Air Force Station ran out of fuel after rough seas forced it to attempt to taxi back to land. As no nearby ships carried aviation gasoline, a fuel truck was lashed to the deck of the , the aircraft was refueled, and it was finally able to take off after five days on the ocean.
On 14 March 1966, an HU-16B, serial number 51-071, attempted a rescue of the crew of an F-4C that had ejected over the Gulf of Tonkin. After landing to pick up the pilot, the aircraft was struck by a mortar round fired from the nearby shore, killing the radio operator and seriously injuring the flight mechanic. The aircraft then sank, drowning the pararescueman, who was tethered to it. The pilot, copilot, flight mechanic, navigator, and both F-4 crew were later rescued by H-3 helicopters. The navigator, Captain Donald Price, was later awarded the Air Force Cross for his actions.
Three days later, on 17 March 1966, an HU-16 was involved in the recovery of Gemini 8.
The HU-16 was also operated by the USCG as both a coastal and long-range, open-ocean SAR aircraft for many years until it was supplanted by the HU-25 Guardian and HC-130 Hercules.
The final USAF HU-16 flight was the delivery of AF Serial No. 51-5282 to the National Museum of the United States Air Force at Wright-Patterson Air Force Base, Ohio, in July 1973 after setting an altitude record of earlier in the month.
The final US Navy HU-16 flight was made 13 August 1976, when an Albatross was delivered to the National Naval Aviation Museum at NAS Pensacola, Florida.
The final USCG HU-16 flight was at Otis Air National Guard Base in Cape Cod in March 1983, when the aircraft type was retired by the USCG.
Other operators
The Pakistan Air Force operated four SA-16As from 1958 to 1968, which it received under the Mutual Defense Assistance Act. No. 4 Squadron was equipped with them while based at Drigh Road Air Base. The SA-16s were used for maritime reconnaissance and coastal patrol during the 1965 War with India. At least one SA-16 was on patrol during the 17-day war, flying 14 missions in support of the Pakistan Navy. They were stored on 19 August 1968.