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VSTOL AIR CRAFTS: Dream Of Aviation Industry



VTSOL fighter aircraft

Mankind has always been inspired by birds. Its dream of soaring through the skies has always enlivened its brilliant minds to build a flying machine. The growth in this Sector was unparalled with golden age of ideas and innovation in design from 1918 to 1939. The aviation sector became an industry when mass production started in 1939 and ever since both, design and production has flourished exceedingly.

Aircrafts are completely integrated into human development cycle with its usage varying from providing food supplies to its usefulness in war, not to mention the large airline sector that transports thousands of people across the world. Despite its revolutionizing part in warfare and transport, aircrafts have a limitation of requiring large runways for landing and takeoff, thus reducing its access only to places where these facilities are available. Especially during a war situation, access to even the remote areas is crucial. The helicopters were a solution to this problem but it was a compromise between speed and accessibility. This gave birth to the Idea of VSTOL Aircrafts.


VSTOL, which is abbreviation for VERTICAL/SHORT TAKEOFF LANDING has been worked upon for quite some time now. The failure of the Iran hostage rescue mission in 1980 demonstrated to the United States military a need for "a new type of aircraft, which could not only take off and land vertically but also could carry combat troops, and do so at speed." The U.S. Department of Defense began the Joint-service Vertical take-off/landing Experimental (JVX) aircraft program in 1981, under U.S. Army leadership. The Department of defense pushed for contractors to form teams. Bell partnered with Boeing Vertol. The Bell Boeing team submitted prototype on 17 February 1983. This was the only proposal received and a preliminary design contract was awarded on 26 April 1983. Since then research has been done vigorously to manufacture an aircraft which can fulfill VSTOL requirement along with the necessary functions for war time. However, this hasn’t been easy; there have been several glitches and incidents which have caused several design overhauls. This has resulted in a considerable cost increase of the project. After years of hard work, first VSTOL aircraft went into mass production in 2005, ‘BELL BOEING V-22 OSPREY’

The Boeing V-22 Osprey is a multi-mission military tilt rotor aircraft. It is takes-off and lands vertically like a helicopter, while its cruise speed is similar to propelled aircraft. The Osprey is powered by two Rolls-Royce AE 1107C Liberty turboshaft engines, delivering 6 150 shaft horsepower each. It has maximum speed of 500 km/h and range of 690 kilometers.

Boeing V-22 VTSOL

V-22 is a predominantly a cargo aircraft with restricted rules of engagement. With the nacelles pointing straight up in conversion mode at 90° the flight computers command the aircraft to fly like a helicopter, with cyclic forces being applied to a conventional swashplate at the rotor hub. With the nacelles in airplane mode (0°) the flaperons, rudder, and elevator fly the aircraft like an airplane. This is a gradual transition and occurs over the rotation range of the nacelles. The lower the nacelles, the greater effect of the airplane-mode control surfaces. The nacelles can rotate past vertical to 97.5° for rearward flight.


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Harrier


The V/STOL aircraft that has been widely used in warfare is non other the the Harrier. Called the Jump Jet, Harrier came into service in the 1970's. It was first developed by the British and later variants were introduced by efforts from the Americans. The Aircraft was a major success in the Gulf war. With capabilities of taking off and landing in small areas, the aircraft almost removed the need for large strips but it had limitations.

The aircraft takes off using nozzles that can change vectors to produce short lifts as shown in the animation


The aircraft was continuously improved, with Boeing being the most active company in it. After taking part in the Iraq war, the aircraft is set to see the end of its carrier and its successor, the F-35 Lockheed Martin Lighting II

The other VSTOL aircraft that is through its design phase, currently close to mass production is the Lockheed Martin F-35 Lightning II.

F-35 VTSOL LOCKHEED MARTIN

The aircraft comes in three variants
§ F-35A, conventional takeoff and landing (CTOL) variant.
§ F-35B, short-take off and vertical-landing (STOVL) variant.
§ F-35C, carrier-based CATOBAR (CV) variant.

In October 2011, two F-35B VTOL aircraft conducted three weeks of initial sea trials aboard USS Wasp (LHD-1), logging more than 28 hours of flight time including 72 short take-offs and 72 vertical landings.

The F-35 has a maximum speed of over Mach 1.6. With a maximum takeoff weight of 60,000 lb. (27,000kg) and its main engine is the Pratt & Whitney F135. The STOVL versions of both power plants use the Rolls-Royce Lift System, patented by Lockheed Martin and developed and built by Rolls-Royce. The Lift System is composed of a lift fan, drive shaft, two roll posts and a "Three Bearing Swivel Module" (3BSM is a thrust vectoring nozzle which allows the main engine exhaust to be deflected downward at the tail of the aircraft. The lift fan is near the front of the aircraft and provides a counter-balancing thrust using two counter-rotating blisks. it is powered by the engine's low-pressure (LP) turbine via a drive shaft and  earbox. Roll control during slow flight is achieved by diverting unheated engine bypass air through wing-ounted thrust nozzles called Roll Posts. Like lift engines, the added lift fan machinery increases payload capacity during vertical flight, but is dead weight during horizontal flight. The cool exhaust of the fan also reduces the amount of hot, high-velocity air that is projected downward during vertical takeoff, which can damage runways and aircraft carrier decks.


F-35 VTSOL

The F-35 has been designed to have a low radar cross section primarily due to the shape of the aircraft and the use of stealthy materials used in construction, including fiber-mat. Unlike the previous generation of fighters, the F-35 was designed with a shape for low-observable characteristics.  F-35 is not only radar stealthy, but it also has infrared and visual signature reduction incorporated.

VSTOL Technology is still in its development phase and is surely going to revolutionize aviation industry.

3 comments:

  1. No mention of the Harrier http://en.wikipedia.org/wiki/Harrier_Jump_Jet

    ReplyDelete
  2. Thank you for the bringing it to our attention...
    We have updated the post and included Harrier

    ReplyDelete
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