The Kaman HH-43 Huskie is a helicopter developed and produced by the American rotorcraft manufacturer Kaman Aircraft.[1] It is perhaps most distinctive for its use of twin intermeshing rotors, having been largely designed by the German aeronautical engineer Anton Flettner.
First flown on 21 April 1953, the HH-43 went into production and was operated by several military air services, including the United States Air Force, the United States Navy and the United States Marine Corps. It was primarily intended for use in aircraft firefighting and rescue in the close vicinity of air bases, but was extensively deployed during the Vietnam War. It was used as a search and rescue platform, having often been enhanced with makeshift modification and new apparatus to better suit the tropical conditions. It was also sold on export to several other countries and also commercially. In its day it set many aviation records in its class, and was first helicopter to experiment with twin-turbine engines even though early designs used piston engines. By the 1970s it was getting replaced by newer designs in military service, typically bigger and higher performance. Many of the helicopters have made their way to the civilian market and museums.
Under the aircraft designation system used by the U.S. Navy pre-1962, Navy and U.S. Marine Corps versions were originally designated as the HTK, HOK or HUK, for their use as training, observation or utility aircraft, respectively. The Air Force Version was the H-43A, however after 1962 the designation system was consolidated, and that became the HH-43A, and the H-43B, the HH-43B. HUK-1 beacme UH-43C, HOK-1 became OH-43D, and HTK-1 became TH-43E.
Development
HOK-1 prototype, 1953
In 1947, the German aeronautical engineer Anton Flettner was brought to the United States as part of Operation Paperclip.[2] He was the developer of the two earlier synchropter designs from Germany during the Second World War: the Flettner Fl 265 which pioneered the synchropter layout, and the slightly later Flettner Fl 282Kolibri ("Hummingbird"), intended for eventual production. Both designs used the principle of counter-rotating side-by-side intermeshing rotors, as the means to solve the problem of torque compensation, normally countered in single–rotor helicopters by a tail rotor, fenestron, NOTAR, or vented blower exhaust. Flettner remained in the United States and became the chief designer of the Kaman company.[3] In this capacity, he designed numerous new helicopters that used the Flettner double rotor.
On 21 April 1953, the first prototype, referred to by the manufacturer as the K-225, made its maiden flight. It was later adopted by the United States Navy as the HTK-1, by which point it was outfitted with a single Lycoming O-435flat-six piston engine, producing 240hp (180kW). During 1954, for an experiment jointly conducted by Kaman and the U.S. Navy, a single HTK-1 was modified and flown with its piston engine having been replaced by a pair of Boeing T50-BO-2turbine engines totaling 380hp (280kW), becoming the world's first twin-turbine helicopter in the process.[4]
Subsequently, a much more powerful Pratt & Whitney R-1340 Waspradial piston engine, capable of producing 600hp (450kW), powered for the far heavier HOK-1, HUK-1, and H-43A versions for the United States Marines, U.S. Navy, and the United States Air Force, respectively. The U.S. Air Force also opted to procure two models that were powered by a single Lycoming T53turboshaft engine: the HH-43B with 860hp (640kW) and the HH-43F with 825hp (615kW).[5] The HH-43B variant established several world records for helicopters in its class during the early 1960s, including for rate of climb, altitude, and distance traveled.[6]
Design
The twin intermeshed rotors of this design
Flight control on the HH-43 was primarily effected by a series of servo-flaps, or large tabs, that was located on the trailing edge of each rotor blade; the actuation of these flaps[how?] would cause the rotors to warp and thus cause the helicopter to either rise or descend as desired.[6] The rotor blades were composed of laminated wood; these restricted the aircraft's use in heavy rains as it could cause blade delamination.[7] There was no conventional tail rotor; its absence gave the rotorcraft a somewhat unusual look.[8] The contra-rotating twin rotors posed a particular hazard on the ground; crews were instructed to avoid approaching or departing the vehicle from the sides, but to instead advance or leave the vehicle from the front, as the blades would be at their highest at this position.[9] Warnings that reinforced this instruction were usually painted on the sides of the pylons which supported the rotor heads.
The interior of the T53 turbine powered HH-43 was divided in two somewhat cramped compartments, the cockpit at the front and an aft crew compartment, which were connected by a small opening that was too narrow for most personnel to pass through (the original radial piston powered versions lacked the aft compartment).[10] Dependent on the mission being performed, the aft compartment would be used to house firefighters, medics, mechanics, and/or rescued personnel; folding sidewall-mounted seats were provided for up to four personnel in this space, while the cockpit normally housed the pilot and co-pilot alone. In a typical configuration, a pair of clamshell doors would be fitted that could open up into the aft area of the rear compartment; in tropical conditions, these doors would often be removed to help cool the interior; in such a configuration, an aft net would be installed to prevent any personnel from falling out of the aircraft. No weapons mounts were officially approved, but some improvised arrangements did see the use of a Browning Automatic Rifle at the aft ramp position.[11]
On the exterior of the rotorcraft, a motorised hoist that was typically used for rescue missions was commonly fitted; control of the hoist was normally exercised from within the aft compartment, but the pilot could also directly control the hoist via the cyclic stick. For rescues at sea, a padded sling, nicknamed the 'horse collar', was fitted to the end of the hoist to aid in retrieval operations.[10] Due to unsatisfactory performance in the field, other devices were usually fitted, including the wire basket "Stokes litter" and a heavy "forest penetrator".[12]
Operational history
USMC OH-43D carries drums, 1956A USAF Huskie aids a practice firefighting operation at Cam Ranh Bay Air Base, Vietnam in 1968
The HH-43 Huskie was procured by the U.S. Air Force; the first H-43As were delivered to the service in November 1958 while the first H-43Bs were accepted in June 1959.[6] The U.S. Air Force primarily procured the type to perform local base rescue operations and to fight aircraft fires. For the latter capacity, the H-43 was commonly outfitted with an airborne fire suppression kit that hung beneath it; this kit, which was developed at Wright-Patterson AFB, weighed only 1,000 pounds yet could output almost 700 gallons of fire-fighting foam. Huskies were usually capable of reaching crash sites before ground vehicles could, saving often-critical time in the rescue.[6] During 1962, the USAF opted to change the H-43 designation to HH-43 to reflect the rotorcraft's role as a rescue vehicle. The HH-43F was the last model delivered to the U.S. Air Force, these differed from earlier models primarily by engine and rotor modifications that produced greater lift.[6]
The Huskie was deployed overseas during the Vietnam War; several detachments of the Pacific Air Rescue Center, the 33d, 36th, 37th, and 38th Air Rescue Squadrons, and the 40th Aerospace Rescue and Recovery Squadron operated the type. Personnel came to commonly refer to the aircraft by its call sign "Pedro". Early on, the rotorcraft's limited range proved to be a hindrance to operations; some crews resorted to an improvised additional fuel tank housed within the aft compartment, increasing fuel capacity by roughly 75 percent.[13] During the conflict, the HH-43 flew more rescue missions than all other rotorcraft combined, largely due to its unique hovering capability; between 1966 and 1970, the type performed a total of 888 combat rescue, comprising 343 aircrew rescues and 545 non-aircrew rescues.[6] The type was also occasionally used as a firefighting vehicle in the theatre as well.[14] Noting the shortcomings of the HH-43, the procurement of newer aircraft, such as the Sikorsky CH-3C and HH-3E, was accelerated; their arrival in quantity supplanted the type and saw its being entirely replaced during the early 1970s.[15][16]
Variants
HH-43AHH-43B Huskie in museumOH-43D Huskie in 1960HH-43F (K-600)
three-seat production version powered by a 240hp (180kW) Lycoming O-435-4 flat-six piston engine for the United States Navy,[19][20] later became TH-43E, 29 built
XHTK-1G
one example for evaluation by the United States Coast Guard
HTK-1K
one example for static tests as a drone
XHOK-1
prototype of United States Marine Corps version, two built
HOK-1
United States Marine Corps version powered by a 600hp (450kW) R-1340-48 Wasp radial piston engine; later became OH-43D, 81 built
In addition to those on static display and the airworthy example at the Olympic Flight Museum, many H-43s are still in use with private owners.[citation needed]
Overall a significant number are in museums, but individual versions can be quite rare. For example, only of two of the 18 USAF HH-43A survived, but neither is on display.[31]
A HH-43B on display at Hubschraubermuseum Bückeburg, Germany
58-1841 – HH-43F on static display at the Military Firefighter Heritage Display at Goodfellow Air Force Base in San Angelo, Texas. It is incorrectly painted with Air Force Serial Number 58-1481. This Huskie was a ground trainer (circa 1962–1976) at Sheppard Air Force Base, so it retained the square-tail empennage that was removed from almost all other Huskies after repeated rotor strikes in heavy winds. After being sold by the military, but before arriving at its current location, it was on display at the Pate Museum of Transportation in Cresson, Texas.[46]
The Kaman SH-2 Seasprite is a ship-based helicopter originally developed and produced by American manufacturer Kaman Aircraft Corporation. It has been typically used as a compact and fast-moving rotorcraft for utility and anti-submarine warfare missions.
The Sikorsky SH-3 Sea King is an American twin-engined anti-submarine warfare (ASW) helicopter designed and built by Sikorsky Aircraft. A landmark design, it was one of the first ASW rotorcraft to use turboshaft engines.
The Westland Whirlwind helicopter was a British licence-built version of the U.S. Sikorsky S-55/H-19 Chickasaw. It primarily served with the Royal Navy's Fleet Air Arm in anti-submarine and search and rescue roles. It was also exported to other countries, and the Whirlwind was succeeded by the turbine powered Westland Wessex which was developed from the H-19/Whirlwind. The helicopter was made in many variants using a variety of radial (piston) and turbine engines.
Kaman Corporation is an American aerospace company, with headquarters in Bloomfield, Connecticut. It was founded in 1945 by Charles Kaman. During the first ten years the company operated exclusively as a designer and manufacturer of several helicopters that set world records and achieved many aviation firsts.
The Sikorsky H-19 Chickasaw is a multi-purpose piston engined helicopter that was used by the United States Army and United States Air Force. It was also license-built by Westland Aircraft as the Westland Whirlwind in the United Kingdom. United States Navy and United States Coast Guard models were designated HO4S, while those of the U.S. Marine Corps were designated HRS. In 1962, the U.S. Navy, U.S. Coast Guard and U.S. Marine Corps versions were all redesignated as H-19s like their U.S. Army and U.S. Air Force counterparts.
The Piasecki H-21 Workhorse/Shawnee is an American helicopter, the fourth of a line of tandem rotor helicopters designed and built by Piasecki Helicopter. Commonly called "the flying banana", it was a multi-mission helicopter, capable of being fitted with wheels, skis or floats.
The Hiller YH-32 Hornet was an American ultralight helicopter built by Hiller Aircraft in the early 1950s. It was a small and unique design because it was powered by two Hiller 8RJ2B ramjet engines mounted on the rotor blade tips which weigh 13 lb (5.9 kg) each and deliver an equivalent of 45 hp (34 kW) for a total of 90 hp (67 kW). Versions of the HJ-1 Hornet were built for the United States Army and the United States Navy in the early 1950s.
The Sikorsky H-34 "Choctaw" is an American piston-engined military helicopter originally designed by Sikorsky as an anti-submarine warfare (ASW) aircraft for the United States Navy. It has seen extended use when adapted to turbine power by the British licensee as the Westland Wessex and Sikorsky as the later S-58T.
The Sikorsky HH-52 Seaguard was an early amphibious helicopter designed and produced by American helicopter manufacturer Sikorsky Aircraft. It was the first of the company's amphibious rotorcraft to fly.
The Sikorsky R-4 is a two-seat helicopter that was designed by Igor Sikorsky with a single, three-bladed main rotor and powered by a radial engine. The R-4 was the world's first large-scale mass-produced helicopter and the first helicopter used by the United States Army Air Forces, the United States Navy, the United States Coast Guard and the United Kingdom's Royal Air Force and Royal Navy. In U.S. Navy and U.S. Coast Guard service, the helicopter was known as the Sikorsky HNS-1. In British service it was known as the Hoverfly.
The Flettner Fl 282 Kolibri (Hummingbird) is a single-seat intermeshing rotor helicopter, or synchropter, produced by Anton Flettner of Germany. According to Yves Le Bec, the Flettner Fl 282 was the world's first series production helicopter.
The Westland WS-51 Dragonfly helicopter was built by Westland Aircraft and was an Anglicised licence-built version of the American Sikorsky S-51.
The Saunders-Roe Skeeter is a two-seat training and scout helicopter that was developed and produced by British manufacturer Saunders-Roe ("Saro") of Cowes and Southampton, in the United Kingdom.
An intermeshing-rotor helicopter is a helicopter with a set of two main rotors turning in opposite directions, with each rotor mast mounted with a slight angle to the other, in a transversely symmetrical manner, so that the blades intermesh without colliding. The arrangement allows the helicopter to function without a tail rotor, which saves power. However, neither rotor lifts directly vertically, which reduces efficiency per each rotor.
The Kaman K-MAX is a helicopter with intermeshing rotors (synchropter) designed and produced by the American manufacturer Kaman Aircraft.
The Sikorsky S-61R is a twin-engine helicopter used in transport or search and rescue roles. A developed version of the S-61/SH-3 Sea King, the S-61R was also built under license by Agusta as the AS-61R. The S-61R served in the United States Air Force as the CH-3C/E Sea King and the HH-3E Jolly Green Giant, and with the United States Coast Guard as the HH-3F, nicknamed "Pelican".
The Bell 47J Ranger is an American single-engine single-rotor light helicopter manufactured by Bell Helicopter. It was an executive variant of the highly successful Bell 47 and was the first helicopter to carry a United States president.
The Kaman K-225 is an American experimental helicopter developed by Kaman Aircraft. One example was modified to become the world's first gas turbine-powered helicopter.
Classic Rotors is a flying aviation museum specializing in helicopters and other rotorcraft, located at the Ramona Airport in Ramona, California, United States.
References
Citations
↑ Wragg, David W. (1973). A Dictionary of Aviation (firsted.). Osprey. p.148. ISBN9780850451634.
Chiles, James R. (2007). The God Machine: From Boomerangs to Black Hawks: The Story of the Helicopter. New York, US: Bantam Books. ISBN978-0-553-80447-8.
Francillon, René J. (1997). McDonnell Douglas Aircraft since 1920: Volume II. London, UK: Putnam. ISBN0-85177-827-5.
Frawley, Gerard (2003). The International Directory of Civil Aircraft, 2003-2004. Fyshwick, Canberra, Act, Australia: Aerospace Publications Pty Ltd. p.155. ISBN1-875671-58-7.
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
