The F-35, the fifth-generation American fighter, is, for many, the best combat aircraft in the world and an increasing number of countries are acquiring it for their armed forces, while Spain thinks about it, before taking a decision. However, what does seem clear is that the Spanish Navy needs the F-35B, the version capable of clearing and vertical landing, the only aircraft that could operate from the LHD Juan Carlos I to replace the obsolete Harriers that still service and that are at the end of their operational life.
But, Is the F-35 or F-35C really very different from the F-35B? It is, without a doubt, an aircraft with a very special engineering. Rolls Royce, manufacturer of the LiftSystem engine that powers these aircraft, explains that its “unrivaled performance comes in part from the latest in digital control and ventilation system technology to deliver responsive, precise and powerful short takeoff and vertical landing ( STOVL) with minimal impact on the overall weight of the airframe.”
The system is a descendant of the Pegasus engine, consisting of the Rolls-Royce LiftFan, driveshaft, three-bearing rotary module (3BSM, a thrust vectoring nozzle at the rear of the aircraft that directs engine exhaust to pass directly with reheat capability for forward flight or deflection down to provide lift) and roll struts. Let’s not forget that this manufacturer has been the industry leader in short takeoff and vertical landing (STOVL) technology for 60 years.
This engine’s driveshaft and clutch deliver up to 29,000 shaft horsepower from the main engine to the LiftFan, providing the conversion needed to take fighter aircraft from conventional flight to STOVL capabilities, which are those required by the Spanish Navy to ensure that the F-35B can land and take off from the deck of the Spanish aircraft carrier, since other types of conventional fighters do not have a sufficient taxiway due to the dimensions of the Juan Carlos I.
The key element, the so-called LiftFan, is capable of giving the engine a cold thrust of 20,000 poundsthanks also to a 50-inch diameter two-stage counter-rotating fan with world-leading hollow-blade disc technology.
When the F-35B was designed it was clear that the aircraft had to be supersonic capable and a suitable vertical lift system that would not compromise this capability was needed for the STOVL variant. This requirement was met by the Rolls-RoyceLiftSystem, developed through a $1.3 billion Systems Demonstration and Development (SDD) contract from Pratt & Whitney. This requirement was met on July 20, 2001.
Instead of using independent lift engines, like the Yakovlev Yak-38, or rotating nozzles for engine bypass air, like the Harrier, the “LiftSystem” has a shaft-driven lift fan, designed by Lockheed Martin and developed by Rolls-Royceand a thrust vectoring nozzle for the engine exhaust that provides lift and also it can withstand afterburning temperatures in conventional flight to reach supersonic speeds. The lift/propulsion system with its three-bearing rotary chute nozzle (3BSD) resembles the plans of the 1973 Convair Model 200 Sea Control Fighter more closely than the previous generation of STOVL designs to which the Harrier belongs.
The team responsible for developing the propulsion system included Lockheed Martin, Northrop Grumman, BAE Systems, Pratt & Whitney and Rolls-Royce, under the leadership of the US Department of Defense’s Office of the Joint Attack Fighter Program. Paul Bevilaqua, Lockheed Martin’s chief engineer for Advanced Development Projects, invented the lift fan propulsion system.
The US Department of Defense (DOD) awarded General Electric and Rolls-Royce a $2.1 billion contract to jointly develop the F136 engine as an alternative to the F135. The LiftSystem was designed for use with any engine. Following the termination of government funding, GE and Rolls-Royce finished further development of the engine in 2011.
Rolls-Royce managed the overall development and integration program in Bristol, UK, and was also responsible for the LiftFan, 3BSM and Roll Post turbomachinery designs. Rolls-Royce in Indianapolis provided the gearbox, clutch, driveshaft and nozzle and carried out the construction and verification tests for the LiftFan.
For vertical flight, 29,000 horsepower is transferred via an extension shaft on the engine fan using a clutch and bevel gearbox to a counter-rotating lift fan located forward of the engine. The fan airflow (low velocity unheated air) exits through thrust vectoring vanes at the bottom of the aircraft and balances lift from the rear nozzle. For lateral stability and roll control, bypass air from the engine is used at a roll post nozzle on each wing. For tilt control, the LiftFan inlet and exhaust nozzle areas vary while keeping total lift constant. Forward and reverse motion is controlled by tilting the 3BSM and the paddles in the LiftFan variable area paddle box nozzle.
By comparison, the maximum thrust of the Rolls-Royce Pegasus 11-61/F402-RR-408, the most powerful version used in the AV-8B, is 23,800 pound-force (106 kN). The weight of the AV-8B is about 46% of the weight of the F-35B.
“This power generates the necessary downthrust to allow ‘hover’ capability and vertical landing. An F-35B has what looks like a square door or opening in the top of the fuselage, behind the pilot and above the lift fan. , to maximize the downward airflow,” explains the Israel Military website.
The engineers explain that the enormous thrust, enough to propel the plane to speeds above the sound barrier, is the result of a fourfold process. Air ducts on either side of the nose “draw” air into the engine, the air being compressed before being ignited with gas, generating what looks like a controlled burst of fire coming out of the rear. The force generated through this process enables the aircraft’s speed, maneuverability and acceleration.
For all these reasons, the Navy considers that this aircraft is the only alternative to replace the vertical takeoff and landing Harriers aboard the “Juan Carlos I”, although they have the drawback of their high price.
But how is this multi-role combat aircraft that serves in some of the major Western armies, including the United States, the United Kingdom, Israel, Norway or Italy?
The F-35, manufactured by Lockheed Martin, is a fifth-generation, single-seat, stealth-capable aircraft developed under the Joint Strike Fighter program to replace the F-16, A-10, F/A-18 and AV- 8B in ground attack, reconnaissance and air defense missions. It was designed in three different versions: the F-35A for conventional takeoff and landing (CTOL), the F-35B capable of short takeoffs and vertical landings, which is what the Spanish Navy needs for its ship “Juan Carlos I”, and the F-35C which is a naval variant capable of operating on aircraft carriers.
Regarding the specific model that the Navy wants, the F-35B STOVL, currently serves in the United States Navy and the United Kingdom, having its bases at the Yuma (Arizona) and Beaufort (Arizona) air bases. South Carlonia), in the American case. The Italian Air Force has also incorporated some of these devices.
The F-35 is a single-engine, medium-weight fighter, similar to a smaller, more conventional, single-engine version of the heavy, twin-engine Lockheed Martin F-22 Raptor, and indeed both models share many common elements.
The STOVL F-35B version is designed to replace the second generation Harrier, which was the first operational vertical landing short takeoff aircraft, whose participation in the Falklands War in 1982 proved its effectiveness in carrier warfare operations. light.
The RAF and the British Navy will use this aircraft to replace the Harrier GR9 on their aircraft carriers, while the United States Marine Corps will use the F-35B to replace the AV-8B Harrier II and F/A-18. Hornet.
The F-35B is similar in size to the US Air Force’s F-35A, but lacks the autocannon, which is optional and must be transported externally in a container under the fuselage, since its place behind the cockpit is occupied in the F-35B by the vertical booster, an innovation that was one of the decisive factors in the selection of the winning design of the JSF program.
During design, two structures were used to test this version: the Lockheed X-35A (later to become the X-35B) and the larger X-35C. 55 One of the first demonstrations of the X-35’s capability was during flight tests for qualification in the JSF program, at LAS where the X-35B took off after a run of less than 150 meters, reached supersonic speed, and landed. vertically. An achievement that the Boeing model could not match.
The F-35B made its maiden flight on February 25, 2009, and on October 3, 2011, began its initial vertical landing tests on the deck of the LHD-type amphibious assault ship USS Wasp.5758
However, the plane, despite its characteristics, has received much criticism, among other things for its high cost, since the costs of the project skyrocketed. In fact, one of the biggest drawbacks of this plane, at least for Spain, is its high price, since each unit would cost between 90 and 130 million euros, not counting the engine, and the Navy would not buy more than a dozen devices. . For this reason, the Air Force is studying whether to join the purchase and also incorporate it into its fleet, with the fundamental objective of replacing the F-18.
Characteristics
Crew: 1 pilot
Length: 15.67m
Wingspan: 10.7m
Height: 4.33m
Surface alar: 42.7 m²
Weight empty: 13,300kg
Weight loaded: 22,470kg
Weight maximum to the takeoff: 31,800 kg
Plant motor: 1× Pratt & Whitney F135 turbofan with afterburner.
Push normal: 28,000 lbf (125 kN) thrust.
Internal Fuel Capacity: 8,382kg
Performance
Maximum operating speed (Vno): 2,205 km/h (1,370 MPH; 1,191 kt) (Mach 1.8)
Autonomy: 2,220 with internal fuel
Ceiling of flight: 18,288 m (60,000 ft)85
Thrust/weight: 0.87
Limit of supported forces: 9G
Armament
cannons: 1× General Dynamics GAU-22/A Equalizer 25mm caliber 4-barrel rotary gun, internally mounted with 180 rounds
Anchor points: 6 underwing pylons with a capacity of 6,800 kg and 2 internal holds with four pylons each with a total capacity of 8,100 kg to carry a combination of general purpose bombs: Mark 82, Mark 83 and Mark 84; cluster bombs: Mk 20 Rockeye II, with WCMD guidance capability; Paveway series laser-guided bombs; JDAM series satellite-guided bombs; GBU-39 Small Diameter Bomb; nuclear bomb B61
Air-to-air missiles:
Short-range: AIM-132 ASRAAM, AIM-9X Sidewinder and IRIS-T
Medium/long range: AIM-120 AMRAAM, MBDA Meteor (pending integration) and the future JDRADM (as of 2020)
Air-to-surface missiles:
Cruise missiles: AGM-154 JSOW, AGM-158 JASSM and SOM (Turkey)
Anti-tank missiles: Brimstone
JSM anti-ship missile
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