User:Steve7c8/sandbox

The cruiser programme of the Minotaur-class and completing the Tiger-class was suspended in 1947, due to lack of immediate threat and the austerity budget imposed by the Labour government and to allow reconsideration of cruiser design. It was thought that a vessel derived from the US Navy's Mitscher-class destroyer destroyer leaders would be sufficient for the limited interim threat perceived from Soviet surface forces. Nevertheless, design work on the Minotaur continued, and the Korean War and arrival of the Soviet Union's 13600 LT Sverdlov-class cruiser saw the Naval staff put cruiser options before the UK Cabinet in 1951. The options presented were:


 * (1) A fully designed Minotaur (1951) cruiser with five 6" twin Mk 26 turrets but AA armament halved to four twin, 3"/70 mounts
 * (2) Mk 3 broad beam Dido cruiser with four 4.5" twin Mk 6 turrets
 * (3) Immediate restart of Tiger class with Mk 24 turrets in A & B and Mk 6 twins in X and Y, likely similar to the final offer to complete the class for the RAN in mid 1945.

The decision was to complete the Tiger to (1948 with Mk 26 twin, 6 inch and 3/70 armament and the alternatives for a new cruiser alternative to the Tiger in November 1954 were the C17, small cruiser of 10,000 ton light with 3 twin Mk 26 6 inch and four Mk 11 L/70 or a new Tiger sized cruiser with a cruiser destroyer armament of two twin 5/56 in a Tiger sized turrets and two twin L70 with cruiser armour and AD/AW processing. The evidence of the size and development difficult of developing rapid fire 5 inch guns of acceptable weight and reliability,however meant in 1955 it was decided to limit cruiser guns options for missile cruisers to the new twin 6 inch a 3/70 and this resulted in the several missile cruiser designs that received staff approval in 1956/7 being similar in dimensions to the Minotaur (1947) and !1951) proposals with two twin Mk 26 6 inch in A and B position and 2-4 twin 3/70 turrets and L/70 light AA. A Minotaur size hull and armour was seen necessary by the staff for major Pacific and Indian Ocean carrier escorts with long range endurance, stores and workshops and Modern guns and missiles combining, surface and AA guns, 3D 984 radar and a viable large Seaslug, armoured magazine for 48 Seaslug missiles 16 nuclear missiles (RAF Bloodhound & USN Terrier AA missiles had special variants) ,. However, First Lord Earl Mountbatten after Suez 'debacle', in 1956 saw 'no use' for Cruisers and closed the RN cruiser design department in April 1957 Mountbatten had always favoured smaller GM Destroyers for Seaslug and vetoed nuclear weapons as impractical for AA on political and escalation grounds. The cruiser department became the new nuclear submarine design unit.

Program origins
The F-35 was the product of the Joint Strike Fighter (JSF) program, which was the merger of various combat aircraft programs from the 1980s and 1990s. One progenitor program was the Defense Advanced Research Projects Agency (DARPA) Advanced Short Take-Off/Vertical Landing (ASTOVL) which ran from 1983 to 1994; ASTOVL aimed to develop a Harrier Jump Jet replacement for the U.K. Royal Navy and the U.S. Marine Corps (USMC). Under one of ASTOVL's classified programs, the Supersonic STOVL Fighter (SSF), Lockheed Skunk Works conducted research for a stealthy supersonic STOVL fighter intended for both U.S. Air Force (USAF) and USMC; a key technology explored was the shaft-driven lift fan (SDLF) system. Lockheed's concept was a single-engine canard delta aircraft weighing about 24000 lb empty. ASTOVL was rechristened as the Common Affordable Lightweight Fighter (CALF) in 1993 and involved Lockheed, McDonnell Douglas, and Boeing.

In 1993, the Joint Advanced Strike Technology (JAST) program emerged following the USAF's Multi-Role Fighter (MRF) and U.S. Navy's (USN) Advanced Fighter-Attack (A/F-X) programs cancellations. MRF, a program for a relatively affordable F-16 replacement, was scaled back and delayed due to post-Cold War defense cuts easing F-16 fleet usage and thus extending its service life as well as increasing budget pressure from the F-22 program. The A/F-X, initially known as the Advanced-Attack (A-X), began in 1991 as the USN's follow-on to the Advanced Tactical Aircraft (ATA) program for an A-6 replacement; the resulting A-12 Avenger II was cancelled due to problems and cost overruns in 1991. In the same year, the termination of the Naval Advanced Tactical Fighter (NATF), an offshoot of USAF's Advanced Tactical Fighter (ATF) program, to replace the F-14 resulted in additional fighter capability being added to A-X, which was then renamed A/F-X. Amid increased budget pressure, the Department of Defense's (DoD) Bottom-Up Review (BUR) in September 1993 announced MRF's and A/F-X's cancellations, with applicable experience brought to the emerging JAST program. JAST was not meant to develop a new aircraft, instead developing requirements, maturing technologies, and demonstrating concepts for advanced strike warfare.

As JAST progressed, the need for concept demonstrator aircraft by 1996 emerged, which would coincide with the full-scale flight demonstrator phase of ASTOVL/CALF. Because the ASTOVL/CALF concept appeared to align with the JAST charter, the two programs were eventually merged in 1994 under the JAST name, with the program now serving the USAF, USMC, and USN. JAST was subsequently renamed the Joint Strike Fighter (JSF) in 1995, with STOVL submissions by McDonnell Douglas, Northrop Grumman, Lockheed Martin, and Boeing. The JSF was expected to eventually replace large numbers of multi-role and strike fighters in the inventories of the US and its allies, including the Harrier, F-16, F/A-18, A-10, and F-117.

International participation is a key aspect of the JSF program, starting with United Kingdom participation in the ASTOVL program. Many international partners requiring modernization of their air forces that deployed the F-16 and F/A-18 were interested in the JSF. The United Kingdom joined JAST/JSF as a founding member in 1995 and thus became the only Tier 1 partner of the JSF program; Italy, the Netherlands, Denmark, Norway, Canada, Australia, and Turkey joined the program during the Concept Demonstration Phase (CDP), with Italy and the Netherlands being Tier 2 partners and the rest Tier 3. Consequently, the aircraft was developed in cooperation with international partners and available for export.

Concept Definition Phase
Boeing and Lockheed Martin were selected in early 1997 for CDP, with their concept demonstrator aircraft designated X-32 and X-35 respectively; the McDonnell Douglas team was eliminated and Northrop Grumman and British Aerospace joined the Lockheed Martin team. Each firm would produce two prototype air vehicles to demonstrate conventional takeoff and landing (CTOL), carrier takeoff and landing (CV), and STOVL. Lockheed Martin's design would leverage the work on the SDLF system conducted under the ASTOVL/CALF program. The key aspect of the X-35 that enabled STOVL operation, the SDLF system consists of the lift fan in the forward center fuselage that could be activated by engaging a clutch that connects the drive shaft to the turbines and thus augmenting the thrust from the engine's swivel nozzle. Research from prior aircraft incorporating similar systems, such as the Convair Model 200, Rockwell XFV-12, and Yakovlev Yak-141, were also taken into consideration. By contrast, Boeing's X-32 employed direct lift system that the augmented turbofan would be reconfigured to when engaging in STOVL operation.

Lockheed Martin's commonality strategy was to replace the STOVL variant's SDLF with a fuel tank and the aft swivel nozzle with a two-dimensional thrust vectoring nozzle for the CTOL variant. This would enable identical aerodynamic configuration for the STOVL and CTOL variants, while the CV variant would have an enlarged wing in order to reduce landing speed for carrier recovery. Due to aerodynamic characteristics and carrier recovery requirements from the JAST merger, the design configuration would settle on a conventional tail compared to the canard delta design from the ASTOVL/CALF; notably, the conventional tail configuration offers much lower risk for carrier recovery compared to the ASTOVL/CALF canard configuration, which was designed without carrier compatibility in mind. This enabled greater commonality between all three variants, as commonality goal was still very high at this stage of the design. Lockheed Martin's prototypes would consist of the X-35A for demonstrating CTOL before converting it to the X-35B for STOVL demonstration and the larger-winged X-35C for CV compatibility demonstration.

The X-35A first flew on 24 October 2000 and conducted flight tests for subsonic and supersonic flying qualities, handling, range, and maneuver performance. After 28 flights, the aircraft was then converted into the X-35B for STOVL testing, with key changes including the addition of the SDLF, the three-bearing swivel module (3BSM), and roll-control ducts. The X-35B would successfully demonstrate the SDLF system by performing stable hover, vertical landing, and short takeoff in less than 500 ft. The X-35C first flew on 16 December 2000 and conducted field landing carrier practice tests.

On 26 October 2001, Lockheed Martin was declared the winner and was awarded the System Development and Demonstration (SDD) contract; Pratt & Whitney was separately awarded to develop the F135 engine for the JSF. The F-35 designation, which was out of sequence with standard DoD numbering, was allegedly determined on the spot by program manager Major General Mike Hough; this came as a surprise even to Lockheed Martin, which had expected the "F-24" designation for the JSF.

System Development and Demonstration


As the JSF program moved into the SDD phase, the X-35 demonstrator design was modified to create the F-35 combat aircraft. The forward fuselage was lengthened by 5 in to make room for mission avionics, while the horizontal stabilizers were moved 2 in aft to retain balance and control. The diverterless supersonic inlet changed from a four-sided to a three-sided cowl shape and was moved 30 in aft. The fuselage section was fuller, the top surface raised by 1 in along the centerline to accommodate weapons bays. Following the designation of the X-35 prototypes, the three variants were designated F-35A (CTOL), F-35B (STOVL), and F-35C (CV). Prime contractor Lockheed Martin performs overall systems integration and final assembly and checkout (FACO), while Northrop Grumman and BAE Systems supply components for mission systems and airframe.

Adding the systems of a fighter aircraft added weight. The F-35B gained the most, largely due to a 2003 decision to enlarge the weapons bays for commonality between variants; the total weight growth was reportedly up to 2200 lb, over 8%, causing all STOVL key performance parameter (KPP) thresholds to be missed. In December 2003, the STOVL Weight Attack Team (SWAT) was formed to reduce the weight increase; changes included more engine thrust, thinned airframe members, smaller weapons bays and vertical stabilizers, less thrust fed to the roll-post outlets, and redesigning the wing-mate joint, electrical elements, and the airframe immediately aft of the cockpit. Many changes from the SWAT effort were applied to all three variants for commonality. By September 2004, these efforts had reduced the F-35B's weight by over 3000 lb, while the F-35A and F-35C were reduced in weight by 2400 lb and 1900 lb respectively. The weight reduction work cost $6.2 billion and caused an 18-month delay.

The first F-35A, designated AA-1, was rolled out in Fort Worth, Texas, on 19 February 2006 and first flew on 15 December 2006. The aircraft was given the name "Lightning II" in 2006.

The software was developed as six releases, or Blocks, for SDD. The first two Blocks, 1A and 1B, readied the F-35 for initial pilot training and multi-level security. Block 2A improved the training capabilities, while 2B was the first combat-ready release planned for the USMC's Initial Operating Capability (IOC). Block 3i retains the capabilities of 2B while having new hardware and was planned for the USAF's IOC. The final release for SDD, Block 3F, would have full flight envelope and all baseline combat capabilities. Alongside software releases, each block also incorporates avionics hardware updates and air vehicle improvements from flight and structural testing. In what is known as "concurrency", some low rate initial production (LRIP) aircraft lots would be delivered in early Block configurations and eventually upgraded to Block 3F once development is complete. After 17,000 flight test hours, the final flight for the SDD phase was completed in April 2018. Like the F-22, the F-35 has been targeted by cyberattacks and technology theft efforts, as well as potential vulnerabilities in the integrity of the supply chain.