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Friday, May 09, 2008

F-35 Joint Strike Fighter program: An overview 04

Read the previous parts: Part 1, Part 2, Part 3

A comparison between the F-35B and Harrier w.r.t. STOVL





true multi-role capability

specialised role










Pilot workload




single seat only

single seat

(twin seat trainer)


single F135/136

(40000lb thrust class)

single Pegasus

(23000lb thrust class)

Weapons carriage

internal and external carriage

external carriage only


all weather precision capability

weather restricts operations

Ability to fly intensive operations

yes, for a sustained period

yes, for short periods


more reliable and ability to predict failures

no ability to predict failures


The F-35 Joint Strike Fighter will be:

  • Four times more effective than legacy fighters in air-to-air engagements

  • Eight times more effective than legacy fighters in prosecuting missions against fixed and mobile targets

  • Three times more effective than legacy fighters in non-traditional Intelligence Surveillance Reconnaissance (ISR) and Suppression of Enemy Air Defenses and Destruction of Enemy Air Defenses (SEAD/DEAD) missions

  • About the same in procurement cost as legacy fighters, but requires significantly less tanker/transport and less infrastructure with a smaller basing footprint


In spite of being far more technically superior than any legacy fighter aircraft, the production cost of the F-35 JSF would be about the same as that of legacy fighter aircraft, making it highly affordable aircraft and offering great value for money to the purchaser. It is able to achieve this by introducing an unprecedented level of commonality between the three variant of aircrafts. The JSF concept is building these three highly common variants on the same production line using flexible manufacturing technology. Cost benefits result from using a flexible manufacturing approach and common subsystems to gain economies of scale. Cost commonality is projected in the range of 70-90 percent; parts commonality will be lower, but emphasis is on commonality in the higher-priced parts. Early interaction between the end-user and developer ensures cost / performance trades are made early, when they can most influence weapon system cost. By adhering to their objective of “Get it right the first time”, they are able to avoid a lot of wasteful expenditure and thus save a lot of resources.



The JSF team would employ advanced assembly methods and highly accurate manufacturing machines to help the F-35 achieve its goals of affordability, quality and assembly speed. The concept of Lean Manufacturing is a key feature in the whole JSF manufacturing program. In fact their objective is to achieve what they term as Leaner-than-Lean Manufacturing.

The F-35 is the first aircraft to be designed entirely using a Solid Modelling Package – CATIA. Three-dimensional solid models provide an exact representation of each part, thus forming the foundation of any subsequent operations. Everybody involved would use the same digitally generated product data to perform their tasks like assembly, supply, CAM programming, and laser-tracking. This paperless method of functioning is expected to save millions of dollars. The product data obtained from the digital model would be used in simulation, tooling, fabrication, assembly and mating. New milling machines accurate to less than the width of a human hair ensure that the F-35’s outer shape is exact and meets its low-observability (stealth) requirements. Assembly time for an F-35 is planned to be less than half that of current-generation fighters. The F-35 JSF production line would be the state-of-the-art model for high-quality, affordable combat aircraft in the 21st century.

The assembly line of the F-35 would make use of industrial Laser Trackers to obtain proper mating of the different modules. The Laser Tracker is a state-of-the-art precision instrument to precisely align the mate components to an extremely close tolerance. The laser tracking technology is used to set up, measure and inspect assembly-tooling details based on CAD models. The 3-D laser interferometer and angular encoders deliver a high-speed measuring rate of 1,000 points per second, and a measurement volume of 70m diameter.

Advanced production processes, including integration of the digital, paperless factory, are being implemented into F-35 production plans. Lean manufacturing principles, incorporation of shortened flow spans, use of a single, flexible production line for all three variants, use of best-value sourcing within a commercial framework — all these steps would yield measurable results in the production phase.


Commonality is the key to affordability – on the assembly line; in common systems that enhance maintenance, field support and service interoperability; and in almost 100 percent commonality of the avionics suite. Component commonality across all three variants reduces unique spares requirements and the logistics footprint. In addition to reduced flyaway costs, the F-35 is designed to affordably integrate new technology during its entire life cycle. While each of the three models looks very similar externally, subtle differences accommodate a relatively wide range of operational needs. All of the three variants fly at supersonic speeds and shoot air-to-air missiles and drop bombs on a target. But they all have vastly different operational suitability requirements. Simply put, the F-35A variant must be affordable, stealthy and match or better the performance characteristics of an F-16. F-35B adds to these characteristics a short-takeoff/vertical landing capability. The F-35C variant must be suitable for carrier operations and must complement the F/A-18E/F.

All models of the Lockheed Martin design look essentially alike, with common outer mold lines across the fuselage and wingbox. They have common structural geometries, share identical wing sweeps and similar tail shapes, and carry weapons in two parallel bays located in front of the main landing gear. Major portions of the fuselage contain common or closely related parts, referred to as cousin parts. The canopy, radar, ejection system, subsystems and most of the avionics are currently common.

The Lockheed Martin design also uses unitized structures to simplify manufacturing and reduce cost. Unitized structures are portions of the aircraft that can be produced as single parts instead of being assembled by hand from a multitude of pieces and hundreds of fasteners. The canopy frame, for example, is fabricated from a single aluminum casting with no fasteners. By comparison, the F-16 canopy frame has 48 parts, 70 shims, and about 500 fasteners.

The JSF's inlet duct is another example. It consists of only three parts fabricated from composite fibers. Each piece of the duct, itself a complex shape, is created by a computer-controlled machine that accurately places composite fibers on a mandrel that then goes into an autoclave for curing. The process, called fiber placement, reduces the time and material associated with laying up complex composite shapes by hand. The company will apply other composite experience gained through its work on the F-22 program and the Japan FS-X program.

The fighter's forward fuselage is another assembly that uses unitized structures. It consists of a unitized aluminium canopy sill, a one-piece cast titanium nose landing gear bay, two resin transfer-molded cockpit side panels, and several large fiberplaced skins and panels. This design approach reduces parts by more than 30 percent and fasteners by about a quarter compared with the F-16 forward fuselage.

Bulkheads provide a good example of manufacturing commonality. Slight variations in thickness or shape, possibly a different material, might be needed to handle different load conditions for each service variant. These variations can be accommodated through common locating points and surfaces, tooling accessories and spacers, and visual work instructions. Moreover, numerically controlled machining can efficiently incorporate these slight variations with very little additional machine programming.


Once the Transfer of Technology [TOT] issues are sorted out, the JSF program would be the finest example of large scale International collaboration undertaken to achieve a common objective.

The F-35 Lightning II, that is being developed as part of the Joint Strike Fighter [JSF] program ushers in a new era in the field of Aircraft design and development and will completely change the face of any future conflict.