VTOL HISTORY AND CONCEPTS

(Most or this information in this VTOL article has been collected form wikipedia.org, and is as such free to reuse)

History of vertical take off and landing aircrafts that are not helicopters

In 1928, Nikolai Tesla received patents for an apparatus for aerial transportation. Tesla called it the "Flivver". It is one of the earliest examples of VTOL aircraft.

In late World War II, German designers studied the possibility of a VTOL aircraft, the Heinkel Lerche, but the plan never got off the drawing board.

An early contribution to VTOL was Rolls-Royce's Thrust Measuring Rig ("flying bedstead") of 1953 . This led to the first VTOL engines as used in the first British VTOL aircraft, the Short SC.1 (1957) which used a 4 vertical lift engines with a horizontal one for forward thrust.

The idea of using the same engine for vertical and horizontal flight by altering the path of the thrust led to the Bristol Siddeley Pegasus engine which used rotating ducts to direct thrust over a range of angles. This was developed side by side with an airframe, the Hawker P.1127, which became subsequently the Kestrel and then entered production as the Hawker Siddeley Harrier though the supersonic Hawker Siddeley P.1154 was cancelled in 1965 .

The Harrier is often flown in STOVL mode which enables it to carry a higher fuel or weapon load over a given distance. The Indian Navy operates Sea Harriers mainly from its aircraft carrier INS Viraat. The United States Marine Corps, and the Italian and Spanish Navies use the AV-8 Harrier II, an advanced derivative of the Harrier. The Harrier II will be replaced in the air arms of the US and UK by a STOVL variant of the F-35 Joint Strike Fighter.

NASA has flown other VTOL craft such as the XV-15 research craft (1977), as have the Soviet Navy and Luftwaffe. Sikorsky tested an aircraft dubbed the X-Wing, which took off in the manner of a helicopter. The rotors would become stationary in mid-flight, and function as wings, providing lift in addition to the static wings. Boeing X-50 is a Canard Rotor/Wing prototype that utilizes a similar concept.

In the 1960s France developed a version of the Dassault Mirage III capable of attaining Mach 1. The Dassault Mirage III - V Balzac (not to be confused with the Mirage 5) achieved transition from vertical to horizontal flight in March of 1966 and reached Mach 1.3 in level flight a short time later.

The Soviet Yak-38 Forger was the Soviet Navy's VTOL aircraft for their light carriers, cargoships, and capital ships. It was developed from the Yak-36 Freehand experimental aircraft. Before the Soviet Union collapsed, a supersonic VTOL aircraft was developed as the Yak-38's successor, the Yak-141, which never went into production. The Yak-141, also called Yak-41 was further developed into the Yak-43.


A German V/STOL VJ101 "Starfighter" on display at the Deutsches Museum, Munich, Germany.In the 1960s and early 70s Germany planned three different VTOL planes. One used the F-104 as a base for research for a V/STOL aircraft. Although two models (X1 and X2) were built, the project was canceled due to high costs and political problems as well as changed needs in the Luftwaffe and NATO. The EWR VJ 101C did perform free VTOL take-offs and landings, as well as test flights beyond mach 1 in the mid- and late 60s. One of the test-aircraft is preserved in the Deutsches Museum in Munich, Germany. The others were the VFW-Fokker VAK 191 B light fighter and reconesaince plane[1], and the Dornier Do 31 E-3 (troop) transport[2], prototypes of the two can be seen at the Deutsches Museum branch at Oberschleißheim Airfield.

The Moller Skycar is a prototype personal VTOL aircraft -- literally, a "flying air vehicle" (PAV). It has, as of this date, never made the transition to level flight, nor has it ever flown with anybody on board.

Aircraft designed to operate in extraterrestrial environments often utilize VTOL. An example of this type of aircraft is the LLRV. Spacecraft typically operate in environments where runways or even a suitably flat surface for skids is nonexistent.


V-22



U.S. Marines jump from a V-22 Osprey, the first production tiltrotor aircraft.The V-22 Osprey is the world's first production tiltrotor aircraft, with one three-bladed proprotor, turboprop engine, and transmission nacelle mounted on each wingtip. The Osprey is a joint service, multimission, military tiltrotor aircraft with both a vertical takeoff and landing (VTOL) and short takeoff and landing capability (STOL). It is designed to perform missions like a conventional helicopter with the long-range, high-speed cruise performance of a turboprop aircraft. The FAA classifies the Osprey as a model of powered lift aircraft.


F-35B

The most spectacular demonstration of the JSF qualifying flight trials was the X-35B's STOVL demonstration where it took off in less than 500 feet, went supersonic, and landed vertically -- a feat that Boeing's entry was unable to achieve.[1]

The JSF program was created to replace various aircraft while keeping development, production, and operating costs down. This was pursued by building three variants of one aircraft, sharing 80% of their parts:

F-35A, a conventional takeoff and landing (CTOL) variant. F-35B, a short-takeoff and vertical-landing (STOVL) variant. F-35C, a carrier-based variant.

X-35B lift fan; the VTOL propulsion system is designed and manufactured by Rolls-Royce plcThe F-35B is the short-takeoff and vertical-landing (STOVL) variant aircraft. The F-35B is similar in size to the Air Force F-35A, trading fuel volume for vertical flight systems. Like the AV-8 Harrier II, guns will be carried in a ventral pod. Vertical flight is by far the riskiest, and in the end, a decisive factor in design.

Instead of lift engines, or rotating nozzles on the engine fan and exhaust like the Pegasus-powered Harrier, the F-35B uses an innovative shaft-driven Lift Fan, patented by Lockheed Martin and developed by Rolls-Royce. Somewhat like a turboprop embedded into the fuselage, engine shaft power is diverted forward via a clutch-and-bevel gearbox to a vertically mounted, contra-rotating lift fan located forward of the main engine in the center of the aircraft. Bypass air from the cruise engine turbofan exhausts through a pair of roll-post nozzles in the wings on either side of the fuselage, while the lift fan balances the vectoring cruise nozzle at the tail. This system is more similar to the Russian Yak-141 than previous STOVL designs, such as the Harrier with thrust vectoring.

Demonstrator X-35 aircraft flew in 2000. A production model first took flight on 15 December 2006.


About helicopter concepts and types


A spinning rotor makes torque that forces the aircraft to spin in the oppsite direction if this torque is not counteracted. The different types of helicopter constructions have the aim of hindering this to happen and also using the torque in a constructive manner when turning is wanted.

One way of chieving this controle is by having one main rotor and a tail rotor that controls the torque. By using different force from the tail rotor, the tail rotor force in combination with the torque can be used to let the helicopter turn in a wanted direction.

Another way of achieving torque controle is by having two main rotors, one at the front and another at the tail. Turning of such a helicopter is achieved by tilting the two rotors in opposite directions.

Still another way of controlling the torque and using it constructively, is by having two counterrotating rotors over each other. Such a helicopter is turned by letting one rotor spin faster than the other. Then the rotor will turn in the spinning direction of the slowest rotor.

The newest concept used commercially implieshaving the rotors at the end of two wings. Such an aircraft can be turned by tilting the rotors in opposite directions. By rotating the wings in flight, such an aircraft can transform the flight from helicopter flight to conventional flight once being in the air and moving forwards.


About helicopter history

The helicopter is the commercially most successful VTOL concept. Here is a summary of the history of the helicopter.

Since 400 BC, the Chinese had a bamboo 11flying top that was used as a children's toy. Eventually, this flying top toy made it to Europe and is depicted in a 1463 European painting. Pao Phu Tau was a 4th-century book in China describing some of the ideas inherent to rotary wing aircraft. In 1493, Leonardo da Vinci first sketched a semi-practical machine, named in his "Codice Atlántico", that could be described as an "aerial screw".

The word "helicopter" (hélicoptère) was coined in 1861 by Gustave de Ponton d'Amécourt, a French inventor who demonstrated a small steam-powered model. Ján Bahýl, a Slovak inventor, developed a helicopter model powered by an internal combustion engine that in 1901 reached a height of 0.5 meters. On May 5, 1905 his helicopter reached 4 meters in altitude and flew for over 1500 meters.

In 1906, two brothers, Jacques and Louis Breguet, began experimenting with airfoils for helicopters and in 1907, those experiments resulted in the Gyroplane No.1. Although there is some discrepancy about the dates, sometime between 14 August and 29 September 1907, the Gyroplane No. 1 lifted its pilot up into the air about two feet (0.6 meters) for a minute. However, the Gyroplane No. 1 proved to be extremely unsteady and required a man at each corner of the airframe to hold it steady. For this reason, the flights of the Gyroplane No. 1 are considered to be the first manned flight of a helicopter, but not a free or untethered flight. That same year, fellow French inventor Paul Cornu designed and built a helicopter that used two 20-foot (6-meter) counter-rotating rotors driven by a 24-hp (18-kW) Antoinette engine. On November 13, 1907, it lifted its inventor to 1 foot (0.3 meters) and remained aloft for 20 seconds. Although this flight was smaller in its achievement than that of the Breguet brothers, it was greater in accomplishment being that it was the first true free flight with a pilot. The Cornu helicopter would achieve a height of nearly 2 meters but also proved to be unstable and was abandoned after only a few flights.

In the early 1920s, Raul Pateras Pescara de Castelluccio, an Argentinian working in Europe, demonstrated one of the first successful applications of cyclic pitch.[10] His coaxial, contra-rotating, biplane rotors were able to be warped to cyclically increase and decrease the lift they produced; and the rotor hub could also tilt, both allowing the aircraft to move laterally without a separate propeller to push or pull it. Pescara is also credited with demonstrating the principle of autorotation, the method by which helicopters land safely after engine failure. By January 1924, Pescara's helicopter No. 3 was capable of flights up to 10 minutes. One of Pescara's contemporaries, Frenchman Etienne Oemichen, set the first helicopter world record recognized by the Fédération Aéronautique Internationale on 14 April 1924, flying his helicopter 360 meters (1,181 feet). On 18 April 1924, Pescara beat Oemichen's record, flying for a distance of 736m (nearly a half mile) in 4 minutes and 11 seconds (about 8 mph, 13 km/h) maintaining a height of six feet. Not to be outdone, Oemichen reclaimed the world record on 4 May when he flew his No. 2 machine again for a 14-minute flight covering 5,550 feet (1.05 mi, 1.692 km) while climbing to a height of 50 feet (15 meters). Oemichen also set the 1-km closed-circuit record at 7 minutes 40 seconds.

During this time, Juan de la Cierva was developing and introducing the first practical autogyro. In 1923, the rotorcraft that became the basis for the modern helicopter began to take shape, in the form of an autogyro.[13] Cierva discovered aerodynamic and structural deficiencies in his early designs that could cause his autogyros to flip over after takeoff. The flapping hinges Cierva designed allowed the rotor to develop lift equally on the left and right halves of the rotor disk. A crash in 1927 led to the development of the drag hinge.[13] These two developments allowed for a stable rotor system, not only in a hover, but in forward flight.

In 1922, Albert Gillis von Baumhauer, a Dutch aeronautical engineer, started studying VTOL rotor craft. His first prototype 'flew' ('hopped' and hovered really) on September 24, 1925, with Dutch Army-Air arm Captain Floris Albert van Heijst at the controls. The controls that Captain van Heijst used were Von Baumhauer's inventions, the cyclic and collective. Patents were granted Von Baumhauer by the British ministry of aviation on January 31, 1927, under number 265,272.

Soviet aeronautical engineers Boris Yuriev and Alexei Cheremukhin began experiments with the TsAGI 1-EA helicopter in 1931. A single rotor helicopter, with dual forward and aft anti-torque propellers, it reached an altitude of 605 meters (1,984 ft) on August 14, 1932 with Cheremukhin at the controls.[14]

The German Focke-Wulf Fw 61 was the first viable helicopter first flying in 1936. The Fw 61 broke all of the helicopter world records in 1937. Nazi Germany used helicopters in small numbers during World War II. Models such as the Flettner Fl 282 Kolibri synchropter were used in the Mediterranean Sea, while the Focke Achgelis Fa 223 Drache was used in Europe.

Mass production of the military version of the Sikorsky XR-4 began in May 1942 for the United States Army; this was used over Burma for rescue duties. It was also used by the Royal Air Force, the first British military unit to be equipped with helicopters being the Helicopter Training School, formed in January 1945 at RAF Andover with nine Sikorsky R-4B Hoverfly I helicopters.

The Bell 47 designed by Arthur Young became the first helicopter to be licensed (in March 1946) for certified civilian use in the United States. Two decades later the Bell 206 became the most successful commercial helicopter ever built with more hours and more industry records than any other aircraft in the world.

Reliable helicopters capable of stable hover flight were developed decades after fixed-wing aircraft. This is largely due to higher engine power density requirements than fixed-wing aircraft. Improvements in fuels and engines during the first half of the 20th century were a critical factor in helicopter development. The availability of lightweight turboshaft engines in the second half of the 20th century, pioneered by the Kaman K-225 synchropter, which first flew with gas turbine power late in 1951, led to the development of larger, faster, and higher-performance helicopters. Turboshaft engines are the preferred powerplant for all but the smallest and least expensive helicopters today.

Today the development of helicopters and related VTOL aircrafts goes towards designing small remote controle VTOL aircrafts that are furnished with surveillance and working tools of all kinds.