Lockheed Martin X-35
Encyclopedia
The Lockheed Martin X-35 was an experimental aircraft developed by Lockheed Martin
for the Joint Strike Fighter Program
. It was declared the winner over the Boeing X-32
and went on to enter production in the early 21st century as the F-35 Lightning II
.
The Joint Strike Fighter evolved out of several requirements for a common fighter to replace existing types. The actual JSF development contract was signed on 16 November 1996. 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.
The first is the F-35A, a conventional takeoff and landing
(CTOL) variant. It it is the smallest and lightest version, and is intended primarily to replace the U.S. Air Force's aging F-16 Fighting Falcon
s and A-10 Thunderbolt II
s. This is the only version with an internal gun, the GAU-22
. This 25 mm cannon is an upgrade from the 20 mm M61 Vulcan
carried by USAF fighters since the F-104 Starfighter
. Deliveries were slated to begin in 2011. The F-35B is the short-takeoff and vertical-landing
(STOVL) variant slated to replace the U.S. Marine Corps
AV-8 Harrier IIs and F/A-18 Hornet
s, and Royal Air Force
/Royal Navy
Harrier GR7/GR9s beginning in 2012. The Royal Navy will use this to replace its Harrier GR7s and the RAF replace its Harrier GR9s. The U.S. Marine Corps will use the F-35B to replace both its AV-8B Harrier IIs and F/A-18 Hornets with a design similar in size to the Air Force F-35A, trading fuel volume for vertical flight systems. Like the Harrier, guns will be carried in a pod. Vertical flight is by far the riskiest, and in the end, a decisive factor in design. Lastly, the F-35C, a carrier
-based variant, will replace the "legacy" F/A-18 Hornet
s and serve as a stealthy complement to the F/A-18E/F Super Hornet
. It will have a larger, folding wing and larger control surfaces for improved low-speed control, and stronger landing gear for the stresses of carrier landings. The larger wing area provides increased range and payload, achieving much the same goal as the much heavier Super Hornet. The U.S. Navy plans to purchase 480 JSF, with deliveries scheduled to start in 2012.
The primary customers and financial backers are the United States and the United Kingdom. Eight other nations are also funding the aircraft's development and will decide in 2006 or later whether or not to purchase it. Total program development costs, less procurement, are estimated at over US$
40 billion, of which the bulk has been underwritten by the United States.
There are three levels of international participation. The United Kingdom is the sole 'Level 1' partner, contributing slightly over US$2 billion, about 10% of the development costs. Level 2 partners are Italy
, which is contributing US$1 billion, and the Netherlands
, US$800 million. At Level 3 are Canada
, US$440 million; Turkey
, US$175 million; Australia
, US$144 million; Norway
, US$122 million; and Denmark
, US$110 million. The levels generally reflect the financial stake in the program, the amount of technology transfer and subcontracts open for bid by national companies, and the priority order in which countries can obtain production aircraft. Israel
and Singapore
have also joined as Security Cooperative Participants.
. In June 1994, Lockheed, which had merged with Martin Marietta
to form Lockheed Martin
, revealed that it had entered into a collaborative relationship with Yakovlev
on their bid for the Joint Advanced Strike Technology competition, consisting of the purchase of design data from the Russian company; according to Jane's All the World's Aircraft 2000-2001 this was data from the cancelled Yak-141 program which employed a similar propulsion system. Although helmet-mounted display systems have already been integrated into some fourth-generation fighters
such as the JAS 39 Gripen
, the F-35 will be the first modern combat aircraft in which helmet-mounted displays will replace a head-up display
altogether.
Instead of lift engines or rotating nozzles on the engine fan like the Harrier, the F-35B uses an innovative shaft-driven Lift Fan
, patented by Lockheed Martin employee Paul Bevilaqua
, 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. The F-35B powerplant effectively acts as a flow multiplier, much as a turbofan
achieves efficiencies by moving unburned air at a lower velocity, and getting the same effect as the Harrier's huge, but supersonically impractical main fan. Like lift engines, this added machinery is dead weight during flight, but increased lifting power increases takeoff payload by even more. The cool fan also reduces the harmful effects of hot, high-velocity air which can harm runway pavement or an aircraft carrier deck. Though risky and complicated, it was made to work to the satisfaction of DOD officials.
During concept definition, two Lockheed airframes were flight-tested: the Lockheed X-35A (which was later converted into the X-35B), and the larger-winged X-35C. Both the Boeing X-32
and X-35 power plants were derived from Pratt & Whitney's F119, with the STOVL variant of the latter incorporating a Rolls-Royce Lift Fan module.
The contract for System Development and Demonstration (SDD) was awarded on 26 October 2001 to Lockheed Martin, whose X-35 beat the Boeing X-32
.
Steven F. Udvar-Hazy Center
, near Washington Dulles International Airport
in Virginia.
Following the end of the competition, the X-35C was transferred to the Patuxent River Naval Air Station Museum in St Mary's county, MD where it reposes near the X-32B STOVL prototype.
Lockheed Martin
Lockheed Martin is an American global aerospace, defense, security, and advanced technology company with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta in March 1995. It is headquartered in Bethesda, Maryland, in the Washington Metropolitan Area....
for the Joint Strike Fighter Program
Joint Strike Fighter Program
Joint Strike Fighter is a development and acquisition program intended to replace a wide range of existing fighter, strike, and ground attack aircraft for the United States, the United Kingdom, Canada, and their allies. After a competition between the Boeing X-32 and the Lockheed Martin X-35, a...
. It was declared the winner over the Boeing X-32
Boeing X-32
The Boeing X-32 was a multi-purpose jet fighter in the Joint Strike Fighter contest. It lost to the Lockheed Martin X-35 demonstrator which was further developed into the F-35 Lightning II.-Background:...
and went on to enter production in the early 21st century as the F-35 Lightning II
F-35 Lightning II
The Lockheed Martin F-35 Lightning II is a family of single-seat, single-engine, fifth generation multirole fighters under development to perform ground attack, reconnaissance, and air defense missions with stealth capability...
.
Development
The Joint Strike Fighter evolved out of several requirements for a common fighter to replace existing types. The actual JSF development contract was signed on 16 November 1996. 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.
The first is the F-35A, a conventional takeoff and landing
CTOL
CTOL is an acronym for conventional take-off and landing, and is the process whereby conventional aircraft take off and land, involving the use of runways. The aircraft will taxi along the runway until its rotation speed is reached, then climb into the air...
(CTOL) variant. It it is the smallest and lightest version, and is intended primarily to replace the U.S. Air Force's aging F-16 Fighting Falcon
F-16 Fighting Falcon
The General Dynamics F-16 Fighting Falcon is a multirole jet fighter aircraft originally developed by General Dynamics for the United States Air Force . Designed as an air superiority day fighter, it evolved into a successful all-weather multirole aircraft. Over 4,400 aircraft have been built since...
s and A-10 Thunderbolt II
A-10 Thunderbolt II
The Fairchild Republic A-10 Thunderbolt II is an American single-seat, twin-engine, straight-wing jet aircraft developed by Fairchild-Republic in the early 1970s. The A-10 was designed for a United States Air Force requirement to provide close air support for ground forces by attacking tanks,...
s. This is the only version with an internal gun, the GAU-22
GAU-12 Equalizer
The General Dynamics GAU-12/U Equalizer is a five-barrel 25 mm Gatling gun-style rotary cannon. The GAU-12/U is used by the United States, Italy and Spain, which mount the weapon in their fighter jets such as the AV-8B Harrier II, airborne gunships such as the Lockheed AC-130, and land-based...
. This 25 mm cannon is an upgrade from the 20 mm M61 Vulcan
M61 Vulcan
The M61 Vulcan is a hydraulically or pneumatically driven, six-barreled, air-cooled, electrically fired Gatling-style rotary cannon which fires 20 mm rounds at an extremely high rate. The M61 and its derivatives have been the principal cannon armament of United States military fixed-wing aircraft...
carried by USAF fighters since the F-104 Starfighter
F-104 Starfighter
The Lockheed F-104 Starfighter is a single-engine, high-performance, supersonic interceptor aircraft originally developed for the United States Air Force by Lockheed. One of the Century Series of aircraft, it served with the USAF from 1958 until 1969, and continued with Air National Guard units...
. Deliveries were slated to begin in 2011. The F-35B is the short-takeoff and vertical-landing
STOVL
STOVL is an acronym for short take off and vertical landing.This is the ability of some aircraft to take off from a short runway or take off vertically if it does not have a very heavy payload and land vertically...
(STOVL) variant slated to replace the U.S. Marine Corps
United States Marine Corps
The United States Marine Corps is a branch of the United States Armed Forces responsible for providing power projection from the sea, using the mobility of the United States Navy to deliver combined-arms task forces rapidly. It is one of seven uniformed services of the United States...
AV-8 Harrier IIs and F/A-18 Hornet
F/A-18 Hornet
The McDonnell Douglas F/A-18 Hornet is a supersonic, all-weather carrier-capable multirole fighter jet, designed to dogfight and attack ground targets . Designed by McDonnell Douglas and Northrop, the F/A-18 was derived from the latter's YF-17 in the 1970s for use by the United States Navy and...
s, and Royal Air Force
Royal Air Force
The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...
/Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
Harrier GR7/GR9s beginning in 2012. The Royal Navy will use this to replace its Harrier GR7s and the RAF replace its Harrier GR9s. The U.S. Marine Corps will use the F-35B to replace both its AV-8B Harrier IIs and F/A-18 Hornets with a design similar in size to the Air Force F-35A, trading fuel volume for vertical flight systems. Like the Harrier, guns will be carried in a pod. Vertical flight is by far the riskiest, and in the end, a decisive factor in design. Lastly, the F-35C, a carrier
Aircraft carrier
An aircraft carrier is a warship designed with a primary mission of deploying and recovering aircraft, acting as a seagoing airbase. Aircraft carriers thus allow a naval force to project air power worldwide without having to depend on local bases for staging aircraft operations...
-based variant, will replace the "legacy" F/A-18 Hornet
F/A-18 Hornet
The McDonnell Douglas F/A-18 Hornet is a supersonic, all-weather carrier-capable multirole fighter jet, designed to dogfight and attack ground targets . Designed by McDonnell Douglas and Northrop, the F/A-18 was derived from the latter's YF-17 in the 1970s for use by the United States Navy and...
s and serve as a stealthy complement to the F/A-18E/F Super Hornet
F/A-18E/F Super Hornet
The Boeing F/A-18E/F Super Hornet is a twin-engine carrier-based multirole fighter aircraft. The F/A-18E single-seat variant and F/A-18F tandem-seat variant are larger and more advanced derivatives of the F/A-18C and D Hornet. The Super Hornet has an internal 20 mm gun and can carry air-to-air...
. It will have a larger, folding wing and larger control surfaces for improved low-speed control, and stronger landing gear for the stresses of carrier landings. The larger wing area provides increased range and payload, achieving much the same goal as the much heavier Super Hornet. The U.S. Navy plans to purchase 480 JSF, with deliveries scheduled to start in 2012.
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
40 billion, of which the bulk has been underwritten by the United States.
There are three levels of international participation. The United Kingdom is the sole 'Level 1' partner, contributing slightly over US$2 billion, about 10% of the development costs. Level 2 partners are Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
, which is contributing US$1 billion, and the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
, US$800 million. At Level 3 are Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, US$440 million; Turkey
Turkey
Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...
, US$175 million; Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, US$144 million; Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
, US$122 million; and Denmark
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
, US$110 million. The levels generally reflect the financial stake in the program, the amount of technology transfer and subcontracts open for bid by national companies, and the priority order in which countries can obtain production aircraft. Israel
Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...
and Singapore
Singapore
Singapore , officially the Republic of Singapore, is a Southeast Asian city-state off the southern tip of the Malay Peninsula, north of the equator. An island country made up of 63 islands, it is separated from Malaysia by the Straits of Johor to its north and from Indonesia's Riau Islands by the...
have also joined as Security Cooperative Participants.
Design
Elements of the F-35 design were pioneered by the F-22 RaptorF-22 Raptor
The Lockheed Martin/Boeing F-22 Raptor is a single-seat, twin-engine fifth-generation supermaneuverable fighter aircraft that uses stealth technology. It was designed primarily as an air superiority fighter, but has additional capabilities that include ground attack, electronic warfare, and signals...
. In June 1994, Lockheed, which had merged with Martin Marietta
Martin Marietta
Martin Marietta Corporation was an American company founded in 1961 through the merger of The Martin Company and American-Marietta Corporation. The combined company became a leader in chemicals, aerospace, and electronics. In 1995, it merged with Lockheed Corporation to form Lockheed Martin. The...
to form Lockheed Martin
Lockheed Martin
Lockheed Martin is an American global aerospace, defense, security, and advanced technology company with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta in March 1995. It is headquartered in Bethesda, Maryland, in the Washington Metropolitan Area....
, revealed that it had entered into a collaborative relationship with Yakovlev
Yakovlev
The Yak Aircraft Corporation is a Russian aircraft designer and manufacturer...
on their bid for the Joint Advanced Strike Technology competition, consisting of the purchase of design data from the Russian company; according to Jane's All the World's Aircraft 2000-2001 this was data from the cancelled Yak-141 program which employed a similar propulsion system. Although helmet-mounted display systems have already been integrated into some fourth-generation fighters
4th generation jet fighter
Aircraft classified by the United States government as fourth-generation jet fighters are those in service approximately from 1980 to 2010, representing the design concepts of the 1970s....
such as the JAS 39 Gripen
JAS 39 Gripen
The Saab JAS 39 Gripen is a lightweight single-engine multirole fighter manufactured by the Swedish aerospace company Saab. It was designed to replace the Saab 35 Draken and 37 Viggen in the Swedish Air Force...
, the F-35 will be the first modern combat aircraft in which helmet-mounted displays will replace a head-up display
Head-Up Display
A head-up display or heads-up display is any transparent display that presents data without requiring users to look away from their usual viewpoints...
altogether.
Instead of lift engines or rotating nozzles on the engine fan like the Harrier, the F-35B uses an innovative shaft-driven Lift Fan
Rolls-Royce LiftSystem
The Rolls-Royce LiftSystem is an innovative propulsion system designed for use in the STOVL variant of the F-35 Lightning II developed during the Joint Strike Fighter Program...
, patented by Lockheed Martin employee Paul Bevilaqua
Paul Bevilaqua
Paul Bevilaqua is an aeronautics engineer at Lockheed Martin in California. In 1990, he invented the lift fan for the Joint Strike Fighter F-35B along with fellow Skunk Works engineer Paul Shumpert.-Life and career:...
, and developed by Rolls-Royce. Somewhat like a turboprop
Turboprop
A turboprop engine is a type of turbine engine which drives an aircraft propeller using a reduction gear.The gas turbine is designed specifically for this application, with almost all of its output being used to drive the propeller...
embedded into the fuselage, engine shaft power is diverted forward via a clutch-and-bevel gearbox to a vertically mounted, contra-rotating
Contra-rotating
Contra-rotating, also referred to as coaxial contra-rotating, is a technique whereby parts of a mechanism rotate in opposite directions about a common axis, usually to minimise the effect of torque. Examples include some aircraft propellers, resulting in the maximum power of a single piston or...
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. The F-35B powerplant effectively acts as a flow multiplier, much as a turbofan
Turbofan
The turbofan is a type of airbreathing jet engine that is widely used for aircraft propulsion. A turbofan combines two types of engines, the turbo portion which is a conventional gas turbine engine, and the fan, a propeller-like ducted fan...
achieves efficiencies by moving unburned air at a lower velocity, and getting the same effect as the Harrier's huge, but supersonically impractical main fan. Like lift engines, this added machinery is dead weight during flight, but increased lifting power increases takeoff payload by even more. The cool fan also reduces the harmful effects of hot, high-velocity air which can harm runway pavement or an aircraft carrier deck. Though risky and complicated, it was made to work to the satisfaction of DOD officials.
During concept definition, two Lockheed airframes were flight-tested: the Lockheed X-35A (which was later converted into the X-35B), and the larger-winged X-35C. Both the Boeing X-32
Boeing X-32
The Boeing X-32 was a multi-purpose jet fighter in the Joint Strike Fighter contest. It lost to the Lockheed Martin X-35 demonstrator which was further developed into the F-35 Lightning II.-Background:...
and X-35 power plants were derived from Pratt & Whitney's F119, with the STOVL variant of the latter incorporating a Rolls-Royce Lift Fan module.
Evaluation
On 20 July 2001, to demonstrate the X-35's unique capability (compared to the X-32), the X-35B STOVL aircraft took off in less than 500 feet (152.4 m), went supersonic, and landed vertically.The contract for System Development and Demonstration (SDD) was awarded on 26 October 2001 to Lockheed Martin, whose X-35 beat the Boeing X-32
Boeing X-32
The Boeing X-32 was a multi-purpose jet fighter in the Joint Strike Fighter contest. It lost to the Lockheed Martin X-35 demonstrator which was further developed into the F-35 Lightning II.-Background:...
.
Aircraft on display
The X-35A was converted into the X-35B for the STOVL part of the competition. It now resides at the National Air and Space MuseumNational Air and Space Museum
The National Air and Space Museum of the Smithsonian Institution holds the largest collection of historic aircraft and spacecraft in the world. It was established in 1976. Located in Washington, D.C., United States, it is a center for research into the history and science of aviation and...
Steven F. Udvar-Hazy Center
Steven F. Udvar-Hazy Center
The Steven F. Udvar-Hazy Center is the Smithsonian National Air and Space Museum 's annex at Washington Dulles International Airport in the Chantilly area of Fairfax County, Virginia, United States....
, near Washington Dulles International Airport
Washington Dulles International Airport
Washington Dulles International Airport is a public airport in Dulles, Virginia, 26 miles west of downtown Washington, D.C. The airport serves the Baltimore-Washington-Northern Virginia metropolitan area centered on the District of Columbia. It is named after John Foster Dulles, Secretary of...
in Virginia.
Following the end of the competition, the X-35C was transferred to the Patuxent River Naval Air Station Museum in St Mary's county, MD where it reposes near the X-32B STOVL prototype.
Specifications (F-35)
Some information is estimated.