Mr. Hisao Hagiwara of Tokyo formed the Jiyu Koku Kenkyusho (Liberty Aeronautical Research Institute) in 1952 in order to develop a helicopter with a jet-driven main rotor.
The JKK completed the design and construction of its first prototype in August, 1952. It was a light single-seat aircraft with a two-blade rotor of 7.3m diameter. Troubles with the transmission system and jet-nozzles led to its abandonment before the end of the year. No greater success was achieved with the original 100mm pulse-jet engine, designed by Mr. Takeo Kimura to power the helicopter, because it proved difficult to ignite and its noise level was unacceptable. Subsequent prototypes have had ramjet engines.
Two of these prototypes, designated the JHX-2 and JHX-3, were completed in March and September, 1955 respectively. Two years later the JKK was disbanded, but Mr. Hagiwara has continued his work with technical assistance from the Civil Aeronautics Agency and the Tokyo Metropolitan Aeronautical Engineering School. The first result of this collaboration is the JHX-4 helicopter, described hereafter.
THE HAGIWARA JHX-4
First flown in late September, 1958, the JHX-4 is a single-seat light helicopter with a two-blade main rotor which is driven by tip-mounted ramjet engines.
The rotor turns at 600 rpm. No weight and performance details are available, except that the JHX-4 has an endurance of 30 minutes.
Jane's All the World's Aircraft, 1959-60
Commander31 wrote:Hagiwara JHX-4
Crew:†1, rotor diameter:†7.3m, height:†2.2m, length:†3.8m
Although relatively unknown the Kayaba Ka-1 autogyro deserves a special place in aviation history since it was the first armed machine of the autogyro/helicopter family to have been used operationally.
In the late thirties the Imperial Japanese Army began to show considerable interest in the use of the autogyro as an artillery spotter and in 1939 a Kellet KD-1A single-engined two-seat autogyro was imported from the United States. Powered by a 225hp Jacobs L-4M4 seven-cylinder air-cooled radial, the KD-1A featured an advanced version of the Kellet direct control rotor system. Unfortunately, shortly after its arrival in Japan, the aircraft was seriously damaged during flight trials at low speeds. The Kellet KD-1A had been damaged beyond repair, but the Japanese Army delivered the wreck to K.K. Kayaba Seisakusho (Kayaba Industrial Co Ltd), a small company doing autogyro research, with instructions to develop a similar machine.
At the request of the Koku Hombu the Kayaba engineering team developed a two-seat observation autogyro based on the Kellet KD-1A but modified to Japanese production standards. Designated Ka-1, this autogyro was powered by a 240hp Argus As 10c eight-cylinder inverted-vee air-cooled engine driving a two-blade propeller, and had a three-blade rotor. Completed in May 1941 at the Sendai (Miyagi Prefecture) plant of Kayaba, the first Ka-1 made its maiden flight at Tamagawa on 26 May, 1941. During its flight test programme the Ka-1 performed remarkably well, demonstrating its ability to take-off after running only 30m in still air. By running the engine at full power and holding the nose 15į up, the Ka-1 could hover and could also execute a full 360į turn while hovering. As maintenance in the field appeared to present less difficulty than anticipated the aircraft was placed in production for service with artillery units.
When shipping losses began to rise alarmingly the Japanese Army commissioned the light escort carrier Akitsu Maru, a converted merchant ship. The short take-off characteristics of the Ka-1 rendered it suitable for operation from this small vessel and accordingly a small number of Ka-ls were modified as anti-submarine patrol aircraft. As the load-carrying capability of the standard two-seat Ka-1 was too limited, the carrier-borne Ka-ls were operated as single-seaters and carried two 60kg depth-charges. In this role the Ka-ls operated over Japanese coastal waters and particularly over the Tsugara and Korean channels. At least one of these aircraft, the Ka-1 KAI, was tested with powder rockets on the rotor tips in an attempt to improve its load-carrying capability while another aircraft was fitted with a 240hp Jacobs L-4MA-7 seven-cylinder air-cooled radial. With Jacobs engine the type became the Ka-2.
R.J.Francillon "Japanese Aircraft of the Pacific War", 1970
The Japanese government, after acquiring and testing a†Kellett KD-1A autogyro in 1939, turned the aircraft over to the Kayaba Industrial Co, which subsequently built an inline-engined version of the aircraft as the†Ka.1. This was powered by a 240hp Kobe engine (licence version of the German Argus As.10C); the first†Ka.1 was flown on 26 May 1941 and eventually some two hundred and forty aircraft of this type were built. They were employed during World War 2 by the Imperial Japanese Army for artillery observation and cooperation duties, and by the Navy for coastal or carrier-based antisubmarine patrol carrying two 60kg bombs or depth charges. One†Ka.1 was modified for trials with small auxiliary rockets at the tips of the rotor blades.
K.Munson "Helicopters And Other Rotorcraft Since 1907", 1968
The Kayaba Ka-1 autogyro was based on an American design, imported to Japan in 1938. An autogyro is a hybrid of helicopter and airplane; while it has a rotor blade chopping overhead, it also has a propellor. Juan de la Cierva, a Spanish engineer, invented the concept and flew an autogyro over the English Channel in 1923. But the autogyro did not gain widespread acceptance.
The Army liked the craft's short take-off span, and especially it slow maintenance requirements. In 1941 production began, with the machines assigned to artillery units for spotting. These carried two crewmen: a pilot and a spotter.
In its ASW configuration, the spotter gave way to two depth charges. Ka-1 anti-submarine aircraft operated from shore bases as well as the two small carriers. They appear to have had one successful submarine sinking.
Had the Army and Navy been able to cooperate on the program, the Ka-1 could have been made devastatingly effective: the Navy had developed a precursor of what later navies would call "dipping sonar," perfectly suited to autogyro use.
American submarines eventually sank both of the carriers.
Sarah wrote:Kayaba "Ka"-Go (Ka-1):
Kayaba "Ka"-Go (Ka-1):
A little model/fan art thingy I found here...
Developed from the three-seat Bell 47G-3B, the KH-4 is a four-seat general purpose helicopter powered by a 201kW Lycoming TVO-435-B1A air-cooled engine. First flight Summer 1960. Apart from changes to cabin to accommodate extra passenger, and new supercharged engine, the KH-4 had a new instrument layout, modified control system and larger fuel capacity. A total of 338 built for civil and military customers between 1960 and 1975.
Jane's Helicopter Markets and Systems
Yippie Kai Yay, Mr. Falcon.
A.J.Pelletier "Bell Aircraft since 1935", 1992
At the beginning of the sixties, Kawasaki decided to develop a version of the three-seat†Bell Model 47G-3, with a stretched cabin to make room for two rows of seats. The first†KH-4 flew in August 1962 and received Japanese type approval on 9 November of that year. By the beginning of 1972, 193 of theKawasaki KH-4 had been built, 19 of which were assigned to the Japanese Army, 23 to the Thai armed forces, four to the South Korean armed forces and one to the Philippines.
G.Apostolo "The Illustrated Encyclopedia of Helicopters", 1984
Leela25 wrote:I cant help but notice you guys pass up the OH-1. Is it too common to add here?
I cant help but notice you guys pass up the OH-1. Is it too common to add here?
It is. The same goes to Mitsubishi's MH2000 I think.
As technology has advanced rapidly in recent decades, the cost of UAVs has fallen rapidly, and now corporations and universities all over the globe are working on various types of UAVs to perform tasks which were previously too expensive, in financial or human terms, to be considered.
Filming a volcanic eruption from close quarters, for example, is something people have simply not been able to do before now.The Yamaha RMAX helicopter is the most advanced commercially available UAV in the world right now.
Long known for its musical instruments and motorcycles, Yamaha's unlikely direction for diversification was the result of yet another Japanese Government initiative which supported the development of high technology to solve practical everyday problems.
Yamaha's development of utility-use unmanned helicopters began with a request in 1983 from the external branch of the Japanese Ministry of Agriculture, Forestry and Fisheries which was also in charge of agricultural aviation. They wanted an unmanned helicopter for crop dusting that could help reduce labor and costs in Japan's labor-strapped rice farming industry.
After extensive research and development efforts, Yamaha completed its first utility-use unmanned helicopter, the 'R-50' in 1987. It was the world's first unmanned helicopter for crop dusting with a 20 kg payload. Adoption at agricultural schools around the country began in 1988, and in 1991 the Ministry of Agriculture, Forestry and Fisheries of Japan passed guidelines for training in the use of the R-50 for crop dusting of rice paddies.
With this, Yamaha Motor began full-scale marketing of the R-50 helicopter, powered by a liquid-cooled, 2-stroke, 98cc, 12 hp engine. The helicopter enabled high-value crops in difficult-to-access paddy fields, often on very hilly land, to be sprayed with pesticides and specialised nutrients. In some cases this replaced labour which had been done by hand at extreme expense, or work done by manned full-scale helicopters which was equally as expensive but faster.
Once development was underway, the myriad applications for a low-cost aerial platform became obvious - aerial photography was suddenly possible at a fraction the cost of the conventional full-scale helicopter. Experienced helicopter pilots are very expensive to hire and remain in short supply despite the hourly rates they command.
By 1998, Yamaha had developed an entirely new machine based on the research work it had done over the previous seven years. The RMAX brought with it dramatic improvements in functionality and operability. Whereas the R-50 had been powered by a 98cc, 12 hp engine, the RMAX mounted a liquid-cooled 2-stroke, 246cc, horizontally-opposed twin-cylinder, crankcase reed valve intake engine rated at 21 hp.
The massive breakthrough of the RMAX though, was its Yamaha-exclusive flight attitude control system YACS, characterised by its vastly improved ability to hover stationary position, and that complete novices could fly the machine. Real helicopters are very hard to fly - we once heard it described as balancing on a golfball with your eyes closed and radio-controlled model helicopters are equally as difficult to fly, though they have the added advantage of not being life-threatening should you fail.
The Yamaha YACS system is such that if you stop all input from the pilot, the machine stops dead still and hovers in one spot. This further lowered the cost of operation (no need for highly-trained personnel), but combined with an almost complete lack of vibration and a range of other sophistications the machine was suddenly suitable for things which had not been possible before. For example, by adding a GPS, Yamaha found it could take very high definition photos from the same spot, time-and-again, over regular time frames, and measure crop growth very accurately.
This resulted in a further upgrade and in Q2, 2003, Yamaha released the 'RMAX Type II G' with the G short for Global Positioning System (GPS). Since then, Yamaha's domestic rival in the UAV market, Yammar, has begun selling RMAX Type II G on an OEM basis, giving the RMAX a virtual 100% market share.
Now the RMAX is not cheap by any standard but that of full-scale aviation. The absolute base-model airframe suitable for agriculture, with a single GPS and the ability to fly only within sight, and no more than five metres above the ground costs US$86,000. The Aerial Photography version can fly up to 100 metres above the ground and costs between US$150,000 and US$230,000. There's a flight research model specced for universities with manual only flight mode, which sells for US$120,000 and none of the base stations and other niceties.
Then there's the 'hamburger-with-the-lot': the fully autonomous R-Max package which includes the ground station, antennas, computers, monitors and two complete autonomous airframes and a four camera system. The price tag is US$1,000,000.00.
The completely autonomous version enables the 'pilot' to watch what's happening from all four cameras at once while the RMAX goes about the flight plan it has been programmed with from the controlling computer. If the operator sees something they want to look at closely, they can override the plan to get closer and then resume the original flight plan or program a new one.
Operating at 10% the hourly rate of a manned helicopter means a whole range of new applications can be found for this new airborne capability.
Some people see an enormous future for the RMAX in surveillance. Because it lands and takes off vertically and does so in a small footprint, it can be used as an auxiliary capability for coast watch vessels, enabling the coast watchers to look at what's happening on islands, up creeks, on the other side of vessels under observation, and to see over the horizon. It has enormous application for the sparying of high-value crops, aerial photography, perimeter control, and even to usage by fire-brigades so they can get a clear picture of what's happening around, for example, a large building which is on fire, or where the heart of a bushfire is.
Interestingly, Yamaha now sees an enormous future for autonomous vehicles and seacraft. The company is beginning to explore the marrying of autonomous control technologies with watercraft, and four-wheeled all-terrain vehicles, (areas in which it already has considerable expertise).
As our story on the DARPA Grand Challenge race for robots in last issue suggested, a successful implementation of this technology has the potential for very large orders from the military.
Right now, the RMAX is the finest example of a commercial autonomous aerial vehicle available. We suspect the bar will be raised rapidly over the coming decade.
-airfoil- wrote:Yamaha Motors R50 / RMax unmanned helicopter
Yamaha Motors R50 / RMax unmanned helicopter
1)†Yamaha RMax II (Agricultural)
2)†Yamaha RMax (photography)
3) Yamaha RMax Type 2
Commander31 wrote:It looks like different rotor configurations were tried. The one I have attached here does not have the protective ring around the rotors.
It looks like different rotor configurations were tried. The one I have attached here does not have the protective ring around the rotors.
Its missing the rings because its just a small-scale prototype.
Information from the following sources:-
1. Rich Nation, Strong Army - National Security And The Technological Transformation Of Japan. Richard J. Samuels, Cornell University 1994.
"In 1953, Itogawa Eizo and Horikoshi Jiro, two of Japans most distinguised wartime aircraft designers, helped form the Japan Helicopter Association with a grant from MITI (?) and the support of the Yomiuri Shimbun, a leading dailey newspaper. Their design, the Yomiuri Y-1, was powered by the wartime Kamikaze-3 engine. The project was abandoned when it failed to acquire U.S Patents for helicopter design."
2. The Aircraft Of The World. Green & Pollinger, Macdonald & Co. 1956.
"The first post-war Japanese helicopter designed for quantity production, the Yomiuri Y-1 powered by a 150 h.p Jinpu radial engine. It is anticipated that production will commence by mid-1956.
Max. speed, 96 m.p.h : Weights : No details available; Rotor diameter, 32ft. 10in. : Overall length, 40ft. 2in."
3. Flight 2nd November 1956.
"Tokyo Kikaika Kogyo Co. - Yomiuri Y-1, sponsored by one of the "Big Three" Japanese newspapers - The Yomiuri - This Bell-like two-seater is powered by a Hitachi Jinpu III seven-cylinder radial of 150 h.p.
Rotor diam. 32.8ft, empty weight. 1,166lb; gross weight. 1,650lb; max. speed 96 m.p.h; cruising range. 200mls."
The aircraft, registered JA7009 is still in existance at the Tokyo Metropolitan College Of Aeronautical Engineering. See http://sts.kahaku.go.jp/sts/detail.php?i__=&key=100710271012&APage=157
Much thanks, Ross! I'll try and add this one to the main site as soon as I can.