The F-35 varieties are designed to replace the older versions of aircrafts because these aircrafts that are used by the Armed Forces are susceptible to errors and risks, which are the common grounds for aircraft accidents. This research paper discusses the new technology behind the making of F-35 Lightning which has three (3) variants: (1) F-35A CTOL, (2) F-35B STOVL, and (3) F-35C CV.
Design and Combat
The F-35 Lightning is designed to take over the U.S. Air Force’s A-10 and F-16, the U.S. Navy’s F/A – 18, U.S. Marine Corps’ AV-8B Harriers and F/A -18, and U.K. Harrier GR.7 and Sea Harriers. The F-35 is also made for unusual air-to-air combat performance, and uses advance stealth to avoid being detected as it employs a powerful sensor in locating, targeting, and destroying multiple enemy fighter aircrafts.
With the supersonic speed, F-35 has the most powerful engine among fighter planes and is capable of carrying weapons internally and avoiding aerodynamic drag of external stores to increase its agility reaching 9 g’s. In stealth mode, it can carry internal weapons load which includes two (2) 2,000 pound joint direct attack munitions (JDAMS) and two (2) advanced medium range air-to-air missiles (AMRAAM). The F-35 can be utilized in either close-in or long-range air-to-air combat.
F-35A Lightning Overview
The F-35A (see Figure 1[i]) fits for the U.S. Air Force for the conventional takeoff and landing (CTOL) which uses a conventional runway for takeoff and landing. The internal capacity of fuel is around nine (9) tons which sustains an unrefueled range of at least 1,200 miles without external tanks. It also carries a 25 mm GAU-22/A cannon internally.
The standard weapons load is two (2) AIM-120C air-to-air missiles and two (2) 2,000-pound GBU-31 JDAM guided weapons. In order to attain all air-to-ground and air-to-air ordnance, the internal weapons bay can be reconfigured. When the stealth is no longer needed in a mission, the F-35A pylons are brought with ordnance that gives the aircraft a weapons payload of at least 18,000 pounds. (Lockheed Martin)
Features and Comparisons with Older Models
The F-35A is able to exceed the performance of the F-16 due to several reasons: (1) stealth, (2) expanded range on internal fuel capacity, and (3) superior avionics. Also other features and abilities like the survival, effectiveness and support are dramatically improved in this aircraft. In comparison with the F-16, F-35A also includes an interior gun and a refueling container. The maneuver characteristics are the same with the F-16 with comparable instant and sustained “High-G” performance.
On the other hand, unlike the F-16, the aircraft is stealthy and has the capability of first-look, first shot. The information gathered from sensors is put together or sorted out before being placed to the helmet-mounted or head-down displays. The aircraft also has advanced electronically scanned array radar. To add more, it also contains internal laser designator and infrared sensors. The range and payload for F-35A as mentioned above is highly greater than the older aircraft models.
Design and Flight Tests
The release of F-35A can surely improve the ability of the pilot in assisting in combat campaigns at longer ranges because of the large fuel capacity and the engine design which is single. As mentioned above the F-35A can carry more than 18,000 pounds of internal fuel and also can carry external fuel as well. This addresses the concern of increased combat scope and longer period spent on the base which is the experience on other aircrafts.
For the flight tests, the Joint Strike Fighter X-35 demonstrator aircraft set a number of flight standards. The X-35A conventional take off and landing had a recorded 27 flights (highest), 27.4 flight hours (highest), 6 pilot checkouts (most), two cancelled flights (fewest) and a 6 1/3 flights per week(highest) in the first month of aircraft testing. The recording was established from October 2000 until August 2001.
The first F-35 demonstrator aircraft left the Air Force’s runway in Plant 42, Palmdale, California on October 24, 2000 and reached Edward Air Force Base, California to begin the flight test program. On November 7, 2000, the F-35A was fueled from a KC-135 tanker for the first time and was able to record its longest flight of 2 hours and 50 minutes. It completed its test flight on November 22 2000 after finishing 27 flights in 30 days and achieving the first JSF supersonic flight the day before. It was brought back to Palmdale to be converted to STOVL F-35B. (Global Security)
The U.S. Air Force is set to receive its first F-35 aircraft by 2008; however the initial operational capability (OIC) for the service will be available in 2011.
F-35B Lightning Overview
The F-35B (see Figure 2[ii]) is designed for the U.S. Marine Corps and the U.K. Royal Air Force and Royal Navy and is regarded as the world’s first short takeoff/vertical landing (STOVL) aircraft which has the ability to operate regularly at supersonic needs. This feature makes F-35B to operate from small ships, roads, and austere bases. It deploys near front-line combat zones which shrinks the distance greatly from the base to the target which also increases sortie rates while removing the need for logistics support.
The internal fuel capacity of F-35B is seven (7) tons that provides unrefueled range of 900 miles without the use of external tanks. Its standard weapons load is two (2) AIM-120C air-to-air missiles and two (2) 1,000-pound GBU-32 JDAM guided weapons. It can also load six GBU-38 small-diameter bombs, and also huge choices of air-to-ground missiles, dispensers, and guided weapons. Same as F-35A, the internal weapons bay is reconfigurable for air-to-ground or air-to-air ordnance or a blend of both.
If stealth is not required, F-35B external pylons are loaded with ordnance which gives the aircraft a weapons payload of more than 15,000 pounds. It is also recognized as the first STOVL stealth fighter. (Lockheed Martin)
Comparison with other models
The F-35B is said to replace the old AV-8B Harrier STOVL attack jets because of their support difficulties. According to Charles Davis (2006), the F-35B has a 25mm “missionized” gun which is put in the belly of the said aircraft and has a combat scope of at least 450NM. This combat radius is twice the specs of other STOVL fighters.
The lift fan which is shaft-driven, including the vectoring rear exhaust nozzles provides power and abilities to the aircraft to (1) take-off in little distances, (2) increase speed reaching supersonic speeds in level flight, and (3) land vertically due to the lift-fan system. “The F-35B’s total vertical lifting thrust is about 39,700 pounds (the aircraft weighs about 30,000 pounds) which is more than 14,000 pounds greater than the engine alone would produce without the lift fan. The F-35B will be the world’s first operational supersonic STOVL aircraft today”. (Davis, 2006)
This kind of aircraft that is going to be used by the U.S. Marines and the UK Royal Air Force is unique from the other kinds of aircraft because of its short takeoff/vertical landing capability. As mentioned in the first requirement for achieving this capability, the airplane must have more vertical lift than weight. The first requirement is regarded to have difficulties in achieving it.
The airplane must have a smaller weight and have an increased thrust-to-weight ratio. The second requirement is fine controllability in every axis of the airplane at zero airspeed. The transition between up-and-away flight and hover must be carefully taken into consideration.
Other critical factor that can affect the aircraft’s overall performance is “the airplane’s hover footprint, which is the propulsion system’s impact on the ground surface or carrier deck. The method in which thrust is developed is the key in producing a benign footprint”. (Global Security) Factors that must be considered are noise levels and heat effects on the deck and on the aircraft itself. Aside from the shaft-driven lift fan the aircraft has slightly shorter scope because the space utilized by the fan system for some of the fuel in the Air Force variant. Still, the aircraft has more than twice the range of an AV-8B on internal fuel and can carry a bigger payload.
Pointing engine thrust directly down produces a tremendous amount of reflected energy, which results in all kinds of effects that make the life of the structures lessen. Acoustic considerations are material considerations because they affect material choices for the underside of the airplane as well as for structures and payloads attached to the airplane. The aircraft shares all of the electronic gear of the Air Force variant. Cockpit layout is also virtually indistinguishable, with the exception of a thrust-vector lever for the aerial mode.
“The JSF X-35 demonstrator aircraft established a number of flight test standards from October 2000 through August 2001. The X-35B short takeoff vertical landing is the first and only aircraft in history to achieve a short-takeoff, level supersonic dash and vertical landing in a single flight. It is also first aircraft to incorporate and fly a shaft-driven lift-fan propulsion system. For the record, it has tallied 17 vertical takeoffs, 14 short takeoffs, 27 vertical landings, and five supersonic flights”. (Global Security)
“The Department of Defense working groups and conferences started to question the community acceptance strategies for some new weapons systems. In particular, the Joint Strike Fighter (JSF) may face a variety of challenges in some possible beddown locations”. (Global Security) The aircraft generates an extraordinary amount of thrust from its single engine, which according to preliminary analyses, contributes to noise and air pollution.
Investigations in San Diego, California revealed air quality limitations that may rule out unrestricted operation of the STOVL (Short Takeoff, Vertical Landing) version of the aircraft. And these will be acquired by the USMC. The highest thrust settings for the aircraft’s F-119 engine will occur during transition to and from vertical flight. Noise and pollutant emissions, especially of Nitrogen oxides may exceed those encountered in any equivalent engine.
On February 2004, there were some setbacks that occurred. As detailed design progressed, the weight estimates from early in the design phase were found to be unrealistic. The program leadership was soon faced with the harsh reality that the short takeoff/vertical landing (STOVL) variant would need to lose as much as 3,000 pounds to meet performance requirements. This was an unexpected negative development, and according to a few, the said fix will be either impossible or too costly and time-consuming. For the solution, the JSF constituted a re-plan phase in order to assess a number of issues pertaining to the aircraft design. (Davis, 2006)
The Special Weapons and Tactics (SWAT) discovered a way of designing the STOVL F-35 that will meet or exceed its performance requirements. The team not only removed more than 3,000 pounds of unwanted estimated weight, but also improved the structure, improved the load paths and brought increased efficiencies to the overall aircraft. “The internal bays of the F-35B STOVL variant were redesigned in late 2004 and are now shorter and reduced in width, compared to the F-35A CTOL model”. (Lockheed Martin)
“This was done to address the weight of the F-35B to meet other more important performance goals. As a result, the F-35B is no longer compatible with JSOW and 2,000-lb JDAM weapons. The largest weapon this F-35 variant can carry internally, as mentioned above, is the GBU-32 1,000-lb version of JDAM”. (Lockheed Martin)