A Look At The F-35 Joint Strike Fighter

The F-35's specification called for sustainability in service and, in an uncharacteristic move for a top-tier warplane, affordability.

Politicians and local press, invited by Rolls-Royce, had a rare chance to experience the FTD (flight training device) for the F-35B Joint Strike Fighter, now officially known as the Lightning II. While our senator and U.S. representative and local press were flying, I was looking for F-35 program folks, “to find stuff out from.”

The F-35B on display was the Marines’ version, the machine with STOVL (Short Take Off, Vertical Landing) capability. The Air Force’s A model (the least-expensive and most-popular) uses conventional runways, and the Navy’s C model sports a tailhook and an 8-foot longer wingspan, as its most-obvious distinctions.

The plane is touted as “the world’s only multi-use fifth-generation fighter,” and has air capabilities similar to the F-16’s, but with important additions. Besides two traditional parameters of traditional fighters, lethality and survivability, the F-35’s specification called for sustainability in service and, in an uncharacteristic move for a top-tier warplane, affordability.

How are these goals met, and what might that mean for the future of manned aircraft in the civilian world?

Designed for simplicity

The F-35, believe it or not, was designed for simplicity. Unlike the normal sequence of engineering teams (design, manufacturability, sustainability) working in series, the F-35 teams at Lockheed-Martin and major component manufacturers like Rolls-Royce and Pratt & Whitney worked in parallel, addressing potential obstacles in real time, building a design that did not have to be frequently re-evaluated.

Danny Conroy, the U.S. program director for Lockheed Martin’s part of the F-35 project, notes that U.S. fighter aircraft average 23 years old, and that they were designed in the 1960s and ‘70s. While he did not say that 23 years of progress would be like dropping a Spad into a dogfight in the middle of WWII, the point could be taken; global opponents, realized and potential, have not been sleeping.

The F-35 is a “high-volume” fighter. While a total of 187 F22 Raptors will constitute the entire production run, some 2,400+ F-35 variants are planned, including 680 for the Navy and Marines. With the “bargain” USAF models costing about the same as a replacement F-16, the F-35 is a reasonably priced machine, itself. As a rough performance equivalent of the F-16 (Mach 1.6 at FL 420; +-9g), and with “survivable stealth” built in, the F-35 is a rational alternative to continuing production of the non-STOVL, non-stealthy Falcon — or FA-18, which is also getting long in the tooth.

Still, with its Rolls-Royce LiftFan design, the F-35B presents a brilliant but unfamiliar new technology. Battle survivability and both field and routine maintenance had to be high on the list of priorities.

Mission Care

Without giving away secret information, Tom Hartmann, Rolls-Royce SVP Customer Business, U.S. government, acknowledges that Rolls-Royce has a Mission Care program in development. The program includes both on-condition and number-of-mission components, all designed to enhance availability.

Unusual components and systems are particular items of interest. Rolls-Royce makes the LiftFan system (Pratt & Whitney provides engines; Lockheed Martin does the airframes), and its novelty also leads to new inspection and test regimens, many of which need to be field-operational. Just how, for instance, to repair, rebalance, and test the 5-foot long, 10-inch diameter carbon drive shaft, or the (brake-technology-derived) clutch assembly at support depots — these problems have not been confronted before, but are essential to mission readiness.

Rolls-Royce’s Gregg Pyers also points out that even the overall assembly needs to be coordinated among the three big contractors; the LiftFan’s vane box is one of the first things to go into the fuselage in manufacturing. The fan itself, however, is installed some 16 months later. What happens when it needs repair, and the fighter is on an aircraft carrier?

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