The Hiller YH-32 Hornet (company designation HJ-1) is 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 Hiller Museum identifies the YH-32A, named the Sally Rand, as the first helicopter gunship.

The Hiller HOE-1 became the first production ramjet helicopter, and the Army and Navy flew a small number of these aircraft for a short time to test and evaluate the technology.

The Hiller HJ-1 Hornet was an early attempt to build a jet-powered helicopter using ramjets, with work beginning in 1948. Before that there had been experiments with the XH-26 Jet Jeep tip rotor pulse jets.The HJ-1 ramjet tipped rotor propels the rotor and the aircraft. Unlike a conventional helicopter, this mechanically simple design avoids the need for a tail rotor.

Unfortunately, the tip speeds on helicopter rotor blades are subsonic, and ramjets are inefficient at subsonic speeds due to low compression ratio of the inlets. Therefore, the Hornet suffered from high fuel consumption and poor range. Also, the vehicle suffered from low translational speeds, and the ramjet tips were extremely noisy. In the event of power loss, autorotation was found to be difficult due to the drag from the ramjet nacelles.

The vehicle exhibited powerful lifting capacity, and there was some hope for military uses, but the high noise, poor range, and high night-time visibility of the ramjet flames failed to attract sales.

The first Hiller Hornets were not ready for delivery until late 1954, due to Hiller certificating the aircraft to Civil Aviation Authority standards rather than military specifications.

Variants

HJ-1
Company designation, one prototype.
YH-32
United States Army, Similar to HJ-1 with two small v-shaped stabilizers, 14 built (2 prototypes and 12 production aircraft).
YH-32A
Two YH-32s modified for trials as an armed helicopter.
XHOE-1
Three HJ-1s for evaluation by the United States Navy in 1951.

Number built   18.

The Hughes XH-17 "Flying Crane" was the first helicopter project for the helicopter division of Hughes Aircraft Company. The XH-17, which had a two-bladed main rotor system with a diameter of 134 feet (41 m), still holds the world record for flying with the largest rotor system. It was capable of flying at a gross weight of more than 50,000 pounds (23,000 kg), but proved too inefficient and cumbersome to be mass-produced beyond the prototype unit.

The XH-17 was a heavy-lift rotorcraft that was designed to lift loads in excess of 15 metric tons. To speed construction, parts of the XH-17 were scavenged from other aircraft. The front wheels came from a North American B-25 Mitchell and the rear wheels from a Douglas C-54 Skymaster. The fuel tank was a bomb bay-mounted unit from a Boeing B-29 Superfortress. The cockpit was from a Waco CG-15 military glider and the tail rotor from a Sikorsky H-19 Chickasaw was used for yaw control.

In the late 1940s, Hughes developed an interest in helicopters. In August 1947, helicopter manufacturer Kellett sold his design for the giant XH-17 Sky Crane to Hughes, who commissioned the development of the XH-17 Flying Crane research vehicle. In 1948, the XH-17 began to take shape. The giant helicopter was tested in Culver City, California over a three-year period beginning in 1952. The XH-17 flew in 1953 at a gross weight in excess of 50,000 pounds (23,000 kg). It still holds the record for flying with the world's largest rotor system. Only one unit was built, since the aircraft was too cumbersome and inefficient to warrant further development.

The propulsion system was unusual. Two General Electric J35 turbojet engines were used, sending bleed air up through the rotor hub. The blades were hollow, and the hot compressed air traveled through the blades to tip jets where fuel was injected. In flight, the main rotor spun at a sedate 88 revolutions per minute, less than half the speed of typical helicopter rotors. Since the rotor was driven at the tips rather than the hub, little torque compensation was required, mostly due to friction in the main rotor bearing. Thus, the XH-17 had a very small tail rotor compared to its main rotor. This drive system was inefficient, limiting the test aircraft to a range of only 40 miles (64 km).

The Hungaro Copter is a Hungarian helicopter produced by Hungaro Copter Limited of Verpelét, an affiliate of the Steel Riders Limited company. The lead engineer for the design was Farkas Gábor. The aircraft is supplied as a kit for amateur construction.

The aircraft was designed to comply with the European microlight aircraft rules. It features a single main rotor and tail rotor, a single-seat enclosed cockpit with a fairing, or an open cockpit without a windshield, skid landing gear and a four-cylinder, four stroke 135 hp (101 kW) Subaru EJ22 or 160 hp (119 kW) Subaru EJ25 automotive conversion engine. The six-cylinder 125 hp (93 kW) D-Motor LF39 powerplant has also been used.

The aircraft fuselage is made from welded steel tubing. Its two-bladed rotor has a diameter of 7.0 m (23.0 ft). The aircraft has a typical empty weight of 300 kg (661 lb) and a gross weight of 430 kg (948 lb), giving a useful load of 130 kg (287 lb).

The construction time from the supplied kit is estimated as 300 hours.

The I.P.D BF-1 Beija-Flôr (English: Humming Bird) was a two-seat light helicopter designed by Henrich Focke.

The BF-1 was built by the aircraft department of the Brazilian Research and Development Institute Instituto de Pesquisa e Desenvolvimento (IPD) (formerly the CTA - Centro Técnico Aeroespacial), using a design of Henrich Focke. It was a conventional three-bladed single rotor helicopter, powered by a 225 hp (168 kW) Continental E225 piston engine, mounted in the nose. The tail unit included a small vertical dorsal fin with a horizontal stabilizer on the starboard side. Two inter-meshing tail rotors, each inclined at 45°, provided pitch and yaw control.

Three prototypes were built, the first flying on 1 January 1959, but the type did not enter production.

The Irkut A-002 is a three-seat, pusher configuration autogyro developed in Russia through the 2000s by the United Constructor Bureau for Light Aircraft team of the Irkutsk Aircraft Production Association (IAPO) "Irkut" as the first independent product. Take-off is possible when wind speed exceeds 8 m/s, otherwise a running start of up to 15 m is necessary. The riveted covering is made of duralumin. The first produced consignment consisted of five autogyros. The A-002M is a further development.

The A-002 has an enclosed, streamlined cabin accessed by large, windowed side doors. The two front seats have dual control, and there is a third seat behind. The fully enclosed, pusher-configuration flat-four AviaSmart engine is situated behind the cabin with a pair of cooling air intakes above its roof. The propeller thrustline is at cabin roof height. The two-blade rotor is mounted on a tall streamlined pylon at the rear of the cabin. In flight the rotor is undriven, but it can be spun up by the engine for jump starts made with no take-off run. Without this spin-up, take-off requires a run of 30 m (98 ft).

The A-002 has composite tail surfaces mounted on a short boom joined to the bottom of the cabin/engine pod. The fin carries a mass- and horn-balanced rudder and an all-moving tailplane at ⅓ fin height. The A-002 has a fixed, wide track tricycle undercarriage with main wheels on cantilever spring legs.

The first flight was on 6 July 2002. Production of five A-002s began in August 2002, but production was halted for further development and no deliveries were made until 2004,. Several revisions were made, including much-enlarged engine air intakes and the addition of endplate fins to the tailpane. The maximum take-off weight (MTOW) of the A-200 increased from 900 to 950 kg (1,980 to 2,090 lb), and both the rotor and fuselage were significantly extended. The more recent A-002M upgrade further raised the MTOW to 1,030 kg (2,270 lb). There have been tests of four- and six-bladed propellers.

In 2005 the autogyro project participated in the Russian Innovation Contest where it was declared that at least 150 units should be sold to pay back the project. In 2006 a renewed version with an AviaSmart engine and a new extended main rotor was named A-002M. In 2008 it was declared about the certification of such autogyro type that year according to the actual aviation rules[clarification needed], however, even by 2012 the certificate has not been received yet. In 2010 they published a specification for a heavier version of A-002M at higher cost. The possibility of jump take-off remained, but it is not considered regular any more due to enhanced load on the bearing structure. It was also reported about developing of the unmanned version. One case of the autogyro's experimental operation by the IrkutskEnergo company in 2006 is known; no further cooperation with this company was reported.

By late 2003 twenty A-002s had been ordered by Susuman Susumanzoloto OAO, a mining company which had received two, and by Irkutskehenergo OAO, which had received another two for power-line inspections. Five had been delivered by 2007.

Variants

A-002    (Specifications below)
Original version.
A-002M
Heavier upgrade, specification released 2010.

It was primarily used for aircraft firefighting and rescue in the close vicinity of air bases, but was later used as a short range overland search and rescue aircraft during the Vietnam War. 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.

In 1947 Anton Flettner, a German aviation engineer, was brought to New York in the United States as part of Operation Paperclip. He was the developer of Germany's Flettner Fl 282 "Kolibri" (Hummingbird), a helicopter employing the "synchropter" principle of intermeshing rotors, a unique design principle that dispenses with the need for a tail rotor. Flettner settled in the US and became the chief designer of the Kaman company, where he designed new helicopters using the synchropter principle.

The Huskie had an unusual intermeshing contra-rotating twin-rotor arrangement with control effected by servo-flaps. The first prototype flew in 1947 and was adopted by the US Navy with a piston engine. In 1954, in an experiment by Kaman and the US Navy, one HTK-1 was modified and flew with its piston engine replaced by two turbine engines, becoming the world's first twin-turbine helicopter. The Air Force later adopted a version with one turboshaft engine: HH-43B and F versions.

This aircraft saw use in the Vietnam War with several detachments of the Pacific Air Rescue Center. During the war, the two-pilot HH-43 Huskie flew more rescue missions than all other aircraft combined, because of its unique hovering capability. The HH-43 was eventually replaced by newer aircraft in the early 1970s.

For details of the 23 variants, click here.

It is optimized for external cargo load operations, and is able to lift a payload of over 6,000 pounds (2,722 kg), which is more than the helicopter's empty weight. An unmanned aerial vehicle version with optional remote control has been developed and evaluated in extended practical service in the war in Afghanistan.

After being out of production for more than a decade, in June 2015 Kaman announced it was restarting production of the K-MAX due to it receiving ten commercial orders.[1] The first flight of a K-MAX from the restarted production took place in May 2017 and the first new-build since 2003 was delivered on July 13, 2017 for firefighting in China.

The K-MAX series is the latest in a long line of Kaman synchropters, the most famous of which is the HH-43 Huskie. The first turbine-powered helicopter was also a Kaman synchropter.

The K-1200 K-MAX "aerial truck" is the world's first helicopter specifically designed, tested, and certified for repetitive external lift operations and vertical reference flight (Kaman received IFR Certification in 1999), an important feature for external load work. The K-MAX can lift almost twice as much as the Bell 205 using a different version of the same engine. The aircraft's narrow, wedge-shaped profile and bulging side windows give the pilot a good view of the load looking out from either side of the aircraft.

For more detail on development and operational history, click here.

The Kamov Ka-22 Vintokryl (rotor-wing, or literally, (air)screw-wing) (Cyrillic:Камов Ка-22 Винтокрыл) (NATO reporting name: Hoop) was a rotorcraft developed by Kamov for the Soviet Air Force. The experimental transport aircraft combined the capabilities of a helicopter for vertical take-off and landing with those of a fixed-wing aircraft for cruise. The Ka-22 carried a large payload, having a hold comparable in size to the Antonov An-12. Eight world records for altitude and speed were set by the Ka-22 in its class, none of which have since been broken.

In order to increase the effective range of a helicopter, Kamov designer Vladimir Barshevsky drew up a design for a helicopter with wings and an aeroplane propulsive system. In 1954 a proposal was agreed to produce three Ka-22s. The programme was delayed and on 28 March 1956 prototypes 2 and 3 were cancelled. The Ka-22 first lifted from the ground on 17 June 1959, and made its first untethered flight on 15 August 1959. Serious control difficulties were encountered, leading to orders being postponed until the problems were solved, and in July 1960 an order was received to manufacture three more Ka-22s.

The Ka-22 was in essence a fixed-wing aircraft with rotors fitted above the wing tips. An engine was mounted on each wing tip, with drive to both a four-bladed tractor propeller and a four-bladed main rotor. The original prototype was powered by 5,900shp Kuznetsov TV-2VK engines, although these were later replaced by the 5,500shp Soloviev D-25VK. The fuselage contained three-seat cockpit above the glazed nose and a main cargo area large enough to contain 80 seats or 16.5 tonnes of cargo. The entire nose could swing open to starboard for loading bulky items. In helicopter mode, the propeller drive was disconnected, and the flaps were lowered to 90 degrees. In fixed-wing mode, the lifting rotors were free to windmill, and the aircraft was controlled by the ailerons and tail surfaces. The twin-wheel landing gear was fixed.

During its short operational history, a total of eight world records were set by the Ka-22, piloted by D.K. Yefremov and V.V. Gromov. On 7 October 1961, with spats over the wheels and a fairing behind the cockpit, a class speed record was set at 356.3 km/h. The spats and fairing were then removed and on 24 November 1961 a payload of 16,485 kg was lifted to 2,557 m.

On 28 August 1962, while on an intermediate stop during a ferry flight to Moscow for acceptance testing, Ka-22 01-01 rolled to the left and crashed inverted, killing the entire crew. The cause was found to be the starboard rotor collective pitch control linkage, and further inspection found that two of the other three Ka-22s suffered from similar problems. Subsequently, in order to improve stability and control, a complex differential autopilot was installed. This sensed attitude and angular accelerations, and fed into the control system.

On 12 August 1964, while involved in Soviet Air Force testing, 01-03 was destroyed. The aircraft entered an uncontrolled turn to the right, and in efforts to correct the Ka-22 pitched into a steep dive. The order was given to abandon the aircraft, and three of the crew survived, but Col S.G. Brovtsev, who was flying, and technician A.F. Rogov, were killed.

After this, the Ka-22 was abandoned, with the Mil Mi-6 having already taken on the heavy helicopter role. Eventually the two surviving machines, 01-02 and 01-04, were scrapped. The Ka-22 was only seen once by western observers during the Cold War during an Aviation Day display in Moscow on 9 July 1961.

The Kamov Ka-26 (NATO reporting name Hoodlum) is a Soviet light utility helicopter with co-axial rotors. It looks like it has twin turbine engines in nacelles on each side of the body, but they are radial engines with turbofans for cooling.

The Ka-26 entered production in 1969 and 816 were built. A variant with a single turboshaft engine is the Ka-126. A twin-turboshaft–powered version is the Ka-226. (All the Ka-26/126/128/226 variants are code-named by NATO as "Hoodlum").

The fuselage of the Ka-26 consists of a fixed, bubble-shaped cockpit containing the pilot and co-pilot, plus a removable, variable box available in medevac, passenger-carrying and crop duster versions. The helicopter can fly with or without the box attached for flexibility.

It is powered by two 325 hp (239 kW) Vedeneyev M-14V-26 radial engines mounted in outboard nacelles.

The Ka-26 is small enough to land on a large truck bed. The reciprocating engines are more responsive than turboshaft engines, but require more maintenance. It runs mostly at 95% power in crop dusting with usually excess payload, leaving little reserve power for emergencies. Due to frequent overloads, the interconnect shaft joining the two engines is prone to breakage and requires frequent inspection.

The standard instrumentation of the Ka-26, like larger naval Kamovs, may be overkill for civilian or crop dusting use. The 18-dials cockpit panel masks a part of the right-downwards view, needed to avoid telephone and power lines at low altitudes. The instrument panel may be simplified to retain the six main dials. As there is a low rotor clearance at the aircraft front, it is approached from the rear when the rotors are turning.

Due to the limitations of the Ka-26, USSR and Romania agreed under the Comecon trade to build a single-turboshaft engine version, the Kamov Ka-126, with better aerodynamics and range.

The Ka-26 is eminently useful for civil agricultural use, especially crop dusting. The coaxial main rotor configuration, which makes the Ka-26 small and agile, also results in a delicate airflow pattern under the helicopter, providing a thorough, yet mild distribution of chemicals onto plants. The Ka-26 is often used to spray grape farms in Hungary, where conventional "main rotor and tail rotor" layout helicopters would damage or up-root the vine-stocks with their powerful airflow.

Hungarian Kamov operators claim that coaxial rotors of the Ka-26 creates an airflow which allows well-atomized pesticides to linger longer in the air, causing more of the residue to settle underneath, rather than on top of, the leaves. This results in a more efficient distribution of pesticides, as most pests and parasites do not live on the top side of foliage. Additionally, the coaxial vortex system is symmetrical, allowing the distribution of the pesticide to be more uniform, without the side currents induced by the tail rotor, making it easier to avoid contaminating adjacent non-crop areas.

In some Warsaw Pact armies, the Ka-26 was used only in the light paratroop or airborne role, but not the civilian agricultural role[citation needed]. In the military role, its slow (150 km/h) cruise speed compared with the Mi-2 (220 km/h) limits effective general-purpose military use, although its shorter length (7.75 m) compared with the Mil Mi-2 (11.9 m) and smaller rotor diameter (13 m vs. 14.6 m) are advantageous for military operations in an urban area. Its operational range is also greater than the Mil-2.

On 30 June 2020, Moldovan police and prosecutors closed down an illegal factory producing unlicensed copies of the Ka-26. The factory had a production line with ten air frames in various stages of completion that were intended for sale to clients in former Soviet countries.

Variants

Ka-26 Hoodlum-A
One- or two-crew utility light helicopter, powered by two 325-hp (239-kW) VMK (Vedeneyev) M-14V-26 radial engines. 850 built.
Ka-26SS
NOTAR technology testbed for the Ka-118 fitted with tail jet beams.
Ka-126 Hoodlum-B
One- or two-crew utility light helicopter, powered by one 720-shp (537-kW) OMKB "Mars" (Glushenkov) TVD-100 turboshaft engine. First flown in 1986, built and developed by Industria Aeronautică Română in Romania. 2 prototypes and 15 series helicopter built.
V-60
A prototype light armed escort helicopter based on the Ka-126.
Ka-128
One prototype, powered by a 722-shp (538-kW) Turbomeca Arriel 1D1 turboshaft engine.
Kamov Ka-226
Six- or seven-seat utility helicopter, powered by two 450-shp (335-kW) Rolls-Royce (Allison) 250-C20R/2 turboshaft engines.

Variants include the Ka-29 assault transport, the Ka-28 downgraded export version, and the Ka-32 for civilian use.

The helicopter was developed for ferrying and anti-submarine warfare. Design work began in 1969 and the first prototype flew in 1973. It was intended to replace the decade-old Kamov Ka-25, and is similar in appearance to its predecessor due to the requirements of fitting in the same hangar space. Like other Kamov military helicopters it has coaxial rotors, removing the need for a tail rotor. Ka-32 variants, e.g. the Klimov-powered Ka-32A11BC, have been certified for commercial operations throughout the world, notably in Canada and Europe.

Ka-32s are used for construction of transmission towers for overhead power lines, as it has somewhat higher lift capacity than the Vertol 107. In Canada, the Ka-32 is used for selective logging as it is able to lift selective species vertically.

For more details, click here.

The Ka-32 is the civilian variant of the military Ka-27 anti-submarine helicopter. It is used in many countries, notably in Canada and Europe. Like other Kamov military helicopters it has coaxial rotors, removing the need for a tail rotor.

Ka-32A11BC multipurpose helicopters have been successfully operated in Portugal for over five years. In 2006, KAMOV JSC won the tender for the supply of Ka-32A11BC firefighting helicopters, to replace Aérospatiale SA 330 Pumas, which have very high operating costs.

Over 240 Ka-32 have been built as of 2019 and have been exported to more than 30 countries; South Korea operates some 50 Ka-32s.

The Ka-32A11BC features a high power-to-weight ratio and ease of handling, owing to its coaxial rotor design. The rotors' diameters are not restricted by the presence of a tail rotor and associated tail boom; this facilitates maneuvering near obstacles and helps assure exceptional accuracy when hovering in heavy smoke and dust conditions. The Ka-32A11BC may be equipped with the Bambi Bucket suspended fire-fighting system of up to five tons capacity. The service life has been extended to up to 32,000 flight hours.

Ka-32s are used for construction of transmission towers for overhead power lines, as it has somewhat higher lift capacity than the Vertol 107. In Canada, the Ka-32 is used for selective logging as it is able to lift selective species vertically.

Variants.

Ka-32A
     Civil transport helicopter. Initial production version.
Ka-32A1
     Fire fighting helicopter, equipped with a helicopter bucket.
Ka-32A2
     Police version, equipped with two searchlights and a loudspeaker.
Ka-32A4
     Special search and rescue, salvage and evacuation version.
Ka-32A7
     Armed version developed from the Ka-27PS.
Ka-32A11BC
     Canadian, Chinese, European-certified version with Klimov TV3-117MA engines and Glass Cockpit. Used by Pegasus Air Services, Indonesia.[20]
Ka-32A12
     Swiss-registered and approved version.
KA-32C
     Little-known custom version.
Ka-32M
     Projected development with 1839kW TV3-117VMA-SB3 engines. Probably replaced by the Ka-32-10 project.

Ka-32S
     (Helix-C) Maritime utility transport, search and rescue helicopter, fitted with an undernose radar.

Ka-32T
     (Helix-C) Utility transport helicopter, with accommodation for two crew and 16 passengers.
Ka-32K
     Flying crane helicopter, fitted with a retractable gondola for a second pilot.

Specifications below are for the Ka-32A variant.

The Kazan Ansat is a Russian light, multipurpose helicopter manufactured by Kazan Helicopters.

Kazan Helicopters in Kazan, Tatarstan, Russia has been one of the main Russian manufacturers of helicopters of the Mikhail Mil bureau design. In the 1990s management realized that there would be a need for light helicopters in Russia, as the fleet of standard Mi-2s was getting older, and the design itself became obsolete. The Mi-2 was the lightest helicopter in large-scale use in the former USSR, despite being larger than most light Western helicopters. At first Kazan Helicopters wanted to develop a helicopter based on the AS 350 Ecureuil in cooperation with Eurocopter, but it failed. As a result, in 1993 Kazan Helicopters organized its own design bureau in order to create a new helicopter (the bureau was officially certified by the Russian authorities in January 1997, designer Valery Dvoeglazov). The helicopter was named Ansat (meaning "light", "simple" or "easy" in the Tatar language).

In 2017–2018, the helicopter has been certified for operation under extremely cold and high temperatures from minus 45°С to plus 50°С, during a series of ground and flight testing. In January 2019, on the basis of trials conducted at Mount Elbrus in 2018, the Federal Air Transport Agency certified the increase in take-off/landing altitude of the Ansat from previous 1,000 m to 3,500 m and approved the helicopter for high-altitude operations. Ansat helicopter optional Emergency Floatation System certified in March 2020. Since May 2020, a specially-adapted medical version is used to transport patients with the novel coronavirus in Russia. In December 2020, the first flight of the modernized Ansat-M took place. The installations of a winch with a lifting capacity of up to 272 kg and an external sling for carrying oversized cargo and extinguishing fires were certified in April 2021.

The Ansat is of a classic construction. It takes a pilot and 10 passengers (one of them sits next to the pilot). The fuselage has a pair of doors in pilot's cab, and a pair of upwards and downwards opening side doors in transport compartment. After the seats have been removed, it can take 1000 kg of cargo inside. On external hook, it can take 1300 kg of load. It is powered with two PW207K turboshaft engines, which produce 630 shp each. It features a four-blade main rotor and two-blade tail rotor.

For more information on the history, procurement, variants and derivatives, click here.

The Kellett XR-8 (later redesignated XH-8) was a helicopter built in the United States during World War II. It was a two-seat machine intended to demonstrate the feasibility of a twin-rotor system and, while it accomplished this, it also demonstrated a number of problems that prevented further development of this particular design.

The successful demonstration of the Sikorsky VS-300 had the USAAF favoring the helicopter over the autogiro as an approach to rotary-winged flight. Realizing this, the Kellett Autogiro Corporation made a proposal to the USAAF on 11 November 1942 for the development of a twin-rotor helicopter that would eliminate the need for a tail rotor and its attendant loss of power. Initially discounted on theoretical grounds, the proposal was re-examined in the light of tests done with models by the Army's Experimental Engineering Section, and was accepted on 7 January the following year. This was followed on 11 September with a contract for nearly $1,000,000 to build two prototypes with the three-bladed rotors contained in Kellett's proposal, along with an alternative two-bladed system.

The resulting aircraft had a stubby, egg-shaped fuselage with a single tail-fin and tricycle undercarriage. Two seats were enclosed side-by-side behind an extensively-glazed nose and the two rotors intermeshed with one another, offset by 12½°. The fuselage construction was of steel-tube, skinned in sheet metal and fabric, and the rotor blades were built of plywood ribs and skin attached to steel tubes. The intermeshing rotors quickly earned it the nickname "eggbeater".

The first flight took place on 7 August 1944 with Kellett chief test pilot Dave Driscoll at the controls. A lack of directional stability was discovered, and was corrected by the addition of two extra tail fins. A far more serious problem was discovered on 7 September, when it was found that a blade from each rotor had collided while the aircraft was in flight. The Air Force therefore ordered Kellett to design a new, rigid rotor system for the XR-8.

In the meantime, the two-bladed rotor system was trialled on the second prototype, beginning in March 1945. This proved immediately unworkable, with severe vibration that was prohibitively difficult to resolve. Similarly, it became apparent that the rigid rotor system was going to require extensive redesign of the aircraft, and this effort was dropped as well.

On 23 January 1946, the XR-8 was accepted for service trials with its original, non-rigid rotors in place. However, the program was canceled almost immediately, and the prototype was eventually handed over to the National Air and Space Museum where it remains in 2008.

The Konner K1 is an Italian helicopter designed and produced by Konner Srl of Amaro, Friuli. The aircraft is supplied complete and ready-to-fly.

The K1 was designed to comply with the European Class 6 microlight helicopter rules. It features a single main rotor and tail rotor, a two-seats-in side-by-side configuration enclosed cockpit with a windshield, skid landing gear and a 250 hp (186 kW) Konner TK-250 turboshaft engine.

The aircraft fuselage is made from carbon fibre. Its three-bladed rotor has a diameter of 6.80 m (22.3 ft). The aircraft has a typical empty weight of 290 kg (639 lb) and a gross weight of 450 kg (992 lb), giving a useful load of 160 kg (353 lb). With full fuel of 140 litres (31 imp gal; 37 US gal) the payload for the pilot, passengers and baggage is 31 kg (68 lb).

The Konner TK-250 turboshaft engine includes full FADEC control that uses only three positions: stop, idle and flight. The powerplant weighs only 50 kg (110 lb) and will burn JP-1, JP-4, diesel fuel or biodiesel.

The design has an electrical power system to aid autorotation in the event of main engine loss in flight.

The Kopter AW09 (formerly the Marenco Swisshelicopter SKYe SH09 and Kopter SH09) is the Leonardo Helicopter Division's five-to-eight seat, single-engine multirole helicopter which is currently under development at Kopter’s facilities. It is a clean-sheet design amongst a market sector dominated by decades-old airframe designs.

The first prototype P1 first flew on 2 October 2014. P2 in February 2016, P3 during November 2018. There have been ongoing delays in first flight of prototypes and TC/commercial deliveries deadlines.

The first prototype P1 first flew on 2 October 2014. P2 in February 2016, P3 during November 2018. There have been ongoing delays in first flight of prototypes and TC/commercial deliveries deadlines.

On 8 April 2020, Italian manufacturer Leonardo announced the closing of the acquisition of Kopter Group AG (Kopter) from Lynwood (Schweiz). The purchase price consists of $185 million, plus earn out. At the time Kopter employed 320 people.

On 21 April 2021 Leonardo rebranded the SH09 single-engine helicopter as the AW09.

The SH09 is a light-medium helicopter, initially intended to be powered by a single Honeywell HTS900 turboshaft engine. It uses a shrouded fenestron tail rotor and the main rotor features a five-bladed bearingless hub; the shrouded tail rotor has a wider diameter and a thinner chord in order to increase airflow, while design aspects such as a narrow tail boom, swept-back tips on the main rotor blades, and the shrouded tail rotor offer reduced noise. The HTS900 is rated at 1,020-shaft-horsepower, and was intended to provide improved performance in hot and high conditions.

The monocoque fuselage is made from composite materials and is equipped with sliding side doors on either side along with a rear clamshell door; it incorporates a series of floor-mounted windows between the pilots' seats for additional vertical visibility. Some of the composite materials used have been produced using out of autoclave composite manufacturing from suppliers such as TenCate and Gurit. According to Marenco, inspiration for the fuselage's design was drawn from the automotive industry. It has been stated that the firm has sought to introduce the cabin volume of medium-sized twin-engine helicopters to the single-engine market.

The SH09 is offered with various different layout configurations. The standard option provides two pilot seats forward and four passenger seats aft, all adjustable fore/aft and up/down. In a high density configuration, five seats are installed in the rear position along with two more passenger seats inline with the pilot's own, which loses the option of the floor window. The use of Kevlar-threaded crashworthy fuel tanks, which are built into the wall and floor of the cargo hold, freed up space to allow for fully adjustable passenger seats in the cabin. The cargo hold is sized to accommodate 10 items of baggage, while the fuel tanks are sized to provide for an endurance of nearly five hours. The rear clamshell door and high-mounted tail boom were designed for air ambulance applications.

For more details of development, design and operational history, click here.

The Layzell Cricket is a single-seat autogyro produced in the United Kingdom for homebuilding, although it was first produced in the early 1970s fully factory-built. It was a typically minimalist design, featuring a pilot's seat semi-enclosed within a fairing, and a pusher engine and large tailfin located aft of the rotor mast. Forty-three of the original Crickets were built by Campbell Aircraft, with the type enjoying a brief revival in 2001 when it was marketed in kit form by Mike Concannon of Cricket Gyroplanes, before reaching production again in 2005 by Layzell Gyroplanes as the Mk.6.

The type remained in production by Layzell through 2011, although by July 2012 the company website had been removed from the internet.

The LCA LH 212 Delta is a two-seat Italian piston engine ultralight helicopter first flown in 2010.

Though strong similarities between the Delta and another Italian helicopter, the 1989 DF Helicopters DF334, have been noted, it is not clear if there are direct relationships between either the machines or their makers. The Delta made its first flight after eight years of development.

The Delta has a standard pod and boom layout, the latter high set, slender and braced with a narrow angle V-form strut pair to its halfway point from bottom of the pod. It has a short span tailplane with small endplate fins raised above the boom on a swept, high aspect ratio fin, forming a T-tail. The tail rotor, mounted on the starboard side of the boom, has its two blades protected from ground strikes by a long, curved tubular bumper.

The pod seats two side-by-side behind a full clear forward transparency. Its skin is carbon fibre over a titanium alloy tube frame. Tandem controls are fitted, with two sets of anti-torque pedals and a T-shaped cyclic control centrally mounted on a console; the single collective pitch lever is placed between the seats. A governor sets the throttle in the absence of pilot input and trim is applied electrically. Small baggage can be stored in under seat lockers. Cabin access is through forward hinged doors in each side. A 84.5 kW (113 hp) Rotax 914 turbocharged, liquid cooled, flat four piston engine with narrow rectangular cheek radiators is mounted behind the seats and partly exposed at the rear, driving a two blade main rotor. The helicopter lands on skids, transversely braced by a pair of airfoil section struts and positioned below the pod on two pairs of similar outward leaning struts, producing a skid track of 1.585 m (5 ft 2 in).

The first flight was in 2010 and marketing began in September 2011 at the Blois international ultra light show. A year later eleven flyaway examples had been built. A kit build version is planned. Number built:  11 by September 2012.

Founded as VPM in 1976 by Vittorio Magni, this company developed the single-seat MT5 and two-seat MT7 gyrocopters. It was renamed Magni Gyro in 1996 and currently produces a range of ultralight autogyros, including the open-cockpit single-seat M 18 Spartan and two-seat M 14 Scout and M 16 Tandem Trainer. In total, around 300 examples were active at the beginning of 2002. The M 20 and M 21 are in development, but the M 19 is not expected to enter production.

MAGNI M 16 TANDEM TRAINER

The M-16 Tandem Trainer is a single engine, two seats in tandem, open cockpit autogyro. It features a pod and boom fuselage with sweptback tailplane and triple fins; rudder on central fin only. The structure is Chrome-alloy 4130 steel; TIG welded: glass fibre pod. It has tricycle undercarriage.  The power plant is one turbocharged 84.6kW Rotax 914 UL flat-four with electric starter, driving a ground-adjustable pitch, three-blade, carbon fibre pusher propeller. Fuel in integral cockpit seat/tank of epoxy/glass fibre, capacity 50 litres.

It was the first light twin-engine helicopter in the world, and the first rotorcraft that could perform aerobatic maneuvers such as inverted loops. The Bo 105 features a revolutionary hingeless rotor system, at that time a pioneering innovation in helicopters when it was introduced into service in 1970. Production of the Bo 105 began at the then-recently merged Messerschmitt-Bölkow-Blohm (MBB). MBB became a part of Eurocopter in 1991, who continued production of the type until 2001. The Bo 105 was formally replaced in Eurocopter's product range by the newer Eurocopter EC135.

The Bo 105 has a reputation for having high levels of maneuverability; certain variants have been designed for aerobatic maneuvers and used for promotional purposes by operators, one such operator in this capacity being professional pilot Aaron Fitzgerald, flying for Red Bull. During the 1970s, the Bo 105 was known for having a great useful load capacity and higher cruise speed than the majority of its competitors. The Bo 105 was known for possessing steady, responsive controls and a good flight attitude.

Perhaps the most significant feature of the Bo 105 is its rotor blades and rotor head. The rotor system is entirely hingeless, the rotor head consisting of a solid titanium block to which the four blades are bolted; the flexibility of the rotor blades works to absorb movements typically requiring hinges in most helicopter rotor designs. The rotor blades are made from reinforced-plastic glass-fiber composite material; the flexibility of the main rotor allows for active elements other than rotor pitch changes to be removed, greatly simplifying maintenance and extending blade lifespan. The reliability of the advanced rotor system is such that, in over six million operating hours across the fleet, there was a total of zero failures (as of 1991).

Besides the two pilots, the cabin can be configured to accommodate up to three passengers on a single rear bench, which can be removed to make room for cargo or a stretcher, which can be loaded and unloaded via the large clamshell doors located at the rear of the fuselage.

For more details of the development, design, operational history, and 29 variants, click here.

Specifications below are for the Bo 105CB light observation, utility transport version. 

The design featured a belt clutch and a transmission which could be engaged to spin the rotor blades to high speed before take-off to produce short takeoff runs. A lever on the rear cockpit wall would select the drive position for the transmission. A single "spin-up lever" on the cockpit left side would then be pressed downward, operating as a collective pitch control to put the blades into flat pitch while simultaneously tensioning the belt clutch. The rotor could be spun to over 500 rpm before takeoff, well above the normal flight range (typically 425 rpm). Release of the spin-up lever would disengage both the clutch and the transmission, while placing the blades into flight pitch. After a very brief takeoff run (typically 25 to 200 feet, depending upon load and winds) adequate flight airspeed would be attained, while the rotor speed decayed to the normal flight range. The rotor was not engine-driven in flight. A strong spring resisted accidental depressing of the spin-up lever while airborne. Dual controls were provided for all functions except the spin-up lever, which was accessible only from the left seat. The aircraft enjoyed nimble handling with light control forces, but suffered from a shallow climb gradient.

The rotor system (hub and blades) is very similar to that found on the early versions of the Hughes 269 / Schweizer 300 series helicopters. The primary difference is in the twist of the blades (or lack thereof), optimized for autorotation in the case of the J-2.

In 1974, the rights were bought by Aero Resources, who planned to return the Super J-2 to production, but could not find a market for the aircraft and no more were built.

The McCulloch Model MC-4 was an American tandem-rotor helicopter and was the first helicopter developed by McCulloch Aircraft Corporation, a division of McCulloch Motors Corporation.[1] It was evaluated by the United States Army as the YH-30 and the United States Navy as the XHUM-1.

The MC-4 was a larger version of the earlier HERC JOV-3 tandem-rotor helicopter and was developed by the McCulloch Aircraft Corporation. The JOV-3 was developed by Jovanovich when he headed the Helicopter Engineering and Research Corporation. The JOV-3 first flew in 1948. In 1949, Jovanovich moved to the McCulloch Motors Corporation, where an enlarged helicopter, the MC-4, first flew in March 1951. It was followed by a similar MC-4C and three evaluation helicopters for the United States Army (as the YH-30). The MC-4C was slightly larger than the MC-4. When the MC-4C was certified in 1953, it was the first tandem-rotor helicopter to be certified in the United States for commercial use. Three examples were evaluated by the United States Army as the YH-30, but the Army's evaluation showed the helicopter to be underpowered.

The YH-30 had a steel tube framework with a light metal skin, A single 200  hp Franklin piston engine was horizontally mounted amidships and powered two intermeshing tandem rotors. It had a fixed-wheel tricycle landing gear with a castering nosewheel.

No civil or military orders were received and Jovanovich formed his own company, the Jovair Corporation, where he modified the MC-4C as a prototype for a four-seat private helicopter designated the Sedan 4E. The Sedan 4E was powered by a 210 hp Franklin 6A-335 engine. A version with a turbocharged engine was designed as the Sedan 4ES and a more basic Sedan 4A for agricultural use. By 1965 a small number of Sedan helicopters were built. In the early 1970s, McCulloch regained the rights to the helicopter designs.

Variants

McCulloch MC-4
Prototype with a 165 hp Franklin engine, two built, one for evaluation by the United States Navy.
McCulloch MC-4A
Variant for evaluation by the United States Navy as the XHUM-1, two built.
McCulloch MC-4C
Prototype with a 200 hp Franklin engine, one built and an additional three for United States Army evaluation as the YH-30.
Jovair Sedan 4E
Production civil four-seat version powered by a 210 hp Franklin 6A-335 engine.
Jovair Sedan 4ES
Sedan with a turbocharged 225 hp Franklin engine.
Jovair Sedan 4A
Simplified agricultural version.

Military designations

YH-30
Military version of the MC-4C, three built. (Specifications below)
CHUM-1
Two MC-4As for evaluation by the United States Navy, later redesignated HUM-1.

The McDonnell 120 Flying Crane, also V-1 Jeep, was a lightweight utility flying crane helicopter designed and built by the McDonnell Aircraft Corporation during the 1950s. The open frame fuselage supported the three gas-producers and main rotor mast, with a small single-seat cockpit in the nose, which was originally open, but later enclosed.

McDonnell had been interested in the flying-crane concept from just after the war, investigating rotors driven directly by ramjets and compressed air tip jets on the McDonnell XH-20 Little Henry, the cancelled McDonnell 79 Big Henry and the McDonnell XV-1 high-speed compound helicopter.

The expected advantages included:

• inherent angle of attack stability
• increased inherent pitch and roll damping
• greatly improved dynamic helicopter stability
• ability to start and stop in high winds;
• no need for tracking and no dampers required
• no possibility of mechanical instability or ground resonance;
• very low vibration
• low maintenance due to absence of highly loaded bearings, reduction gears, shafting, and anti-torque rotor
• automatic rotor speed control.

McDonnell started development of a private-venture flying crane helicopter in December 1956, progressing rapidly with a mock-up in January 1957 and the first of two prototypes flying on 13 November 1957, piloted by John R. Noll. The airframe of the Model 120 was very simple, comprising a welded steel-tube open structure, with the three-bladed main-rotor mast and gas-producers attached without covering. Rotor drive was by compressed air rotor-tip jets, fed by three 200 hp (149 kW) gas power AiResearch GTC 85-135 gas-producers.

The Model 120 was only ever intended to carry loads under-slung or attached directly to cargo hooks on the underside of the top fuselage beam, including specialised pods. Although aimed at the US Army the Model 120 was also evaluated by the US Navy at the Naval Air Test Center (NATC), NAS Patuxent River, in September 1959. The Model 120 experienced powerplant problems initially, but demonstrated an excellent load to weight ratio of 1.5:1, but despite the proven performance no orders were forthcoming and cancellation of the project in February 1960 signalled the end of McDonnell's helicopter aspirations. Only two examples were built.

The MD 500 was developed from the Hughes 500, a civilian version of the US Army's OH-6A Cayuse/Loach. The series currently includes the MD 500E, MD 520N, and MD 530F.

The successful Hughes 500/MD 500 series began life in response to a U.S. Army requirement for a Light Observation Helicopter (LOH). Hughes' Model 369 won the contest against competition from Bell and Hiller. The subsequent OH-6 Cayuse first flew in February 1963.

The 500 series design features shock-absorbing landing skid struts, a turboshaft engine mounted at a 45-degree angle toward the rear of the cabin pod, a fuel tank cell under the floor and the battery in the nose. The engine exhaust port is located at the end of the cabin pod underneath the tailboom. It has a short-diameter main rotor system and a short tail, giving it agile control response and is less susceptible to weather-cocking.

Manufactured under licence by Breda Nardi Costruzioni Aeronautiche SpA as the Breda Nardi NH-500D.

For more details of the civilian version, click here. For details of the military MD 500 Defender, click here.

Specifications below are for the 500C variant.

Designed in the early 1990s by McDonnell Douglas Helicopter Systems, it is currently produced by MD Helicopters. There have been two models, the original MD 900, and its successor, the MD 902.

In January 1989, McDonnell Douglas Helicopters officially launched the development of the Explorer, initially referred to as MDX. The Explorer was the first McDonnell Douglas helicopter to incorporate the NOTAR system from its initial design. McDonnell Douglas partnered with Hawker de Havilland of Australia to manufacture the airframes. 10 prototypes were built with seven being used for ground tests. McDonnell Douglas Helicopters became a launch customer for Pratt & Whitney Canada's PW200 series of engines, with an exclusive agreement to power the first 128 Explorers with two PW206As.

The MD Explorer features the NOTAR anti-torque system, with benefits including increased safety, far lower noise levels and performance and controllability enhancements. Instead of an anti-torque tail rotor, a fan exhaust is directed out of slots in the tail boom, using the Coandă effect for yaw control. Boeing retains the design rights to the NOTAR technology despite selling the former McDonnell Douglas civil helicopter line to MD Helicopters in early 1999. The Explorer also features a bearingless five blade main rotor with composite blades, plus carbonfibre construction tail and fuselage.

The MD900  is used extensively in police ans air ambulance rolls. The aircraft in the photo above, G-SASH, is operated by the Yorkshire Air Ambulance and is featured in the Foxtel TV program Air Ambulance.

For details of the development and 6 variants, click here.