| By Bill Sweetman |
| A total production rate several times higher than that of recent fighters and a modern design and manufacturing line mean the Joint Strike Fighter (JSF) will offer more capability for less money than competitors, program officials maintain. Decisions to be taken by the Obama administration, in light of numbers to be released in the next few weeks, will influence to what extent that plan becomes reality. The U.S. Air Force plans to acquire 1,763 JSFs to replace all its fighters except the F-22. Buying 80 per year to match the retirement rate of older aircraft underpins the program’s economics. Air Force officers warn, however, that the service will need more money to support more than 48 JSFs a year. The JSF program is concurrent—systems development and demonstration (SDD) and low-rate initial production (LRIP) overlap. This was done to build the production rate gradually and reach 200-plus jets a year immediately after testing. The first of seven planned LRIP batches was ordered in 2007. But since last year’s decision to slip the end of SDD to 2014, that year’s batch has been rebadged as an eighth LRIP buy. One sign of the program’s size is that its “low-rate” phase will build 550 aircraft. The likelihood of difficulties in the program is the subject of debate. The U.S. Government Accountability Office (GAO) cited a potential 27-month, $13-billion slip last March, based on an independent assessment sought from Naval Air Systems Command. The Pentagon commissioned a Joint Estimating Team (JET), which predicted a two-year slip and $15-billion SDD overrun.  Maj. Gen. Charles Davis speaks at the rollout of the first “weight-optimized” F-35A in 2007.Credit: LOCKHEED MARTIN Maj. Gen. Charles Davis, program office director, says JET based its projections on two factors: the F-22 flight-test program’s productivity and technical issues like the F/A-18E/F wing-drop problem. Davis says that some of the F-22’s problems were caused by funding cuts (the budget for spares was reduced early on, hobbling flight tests later), and that better modeling and simulation will reduce the number of test problems. The JET disagrees with the program office about cost savings from the use of “cousin” parts: components that differ in detail from one JSF variant to another, but are made with the same processes and materials. The program office says they will be 80% cheaper than if they were different; JET says 25% cheaper. This is important because there are likely to be many cousin parts, given the differences in airframe weight among the three versions. The carrier-based F-35C is expected to have an operating empty weight 5,500 lb. higher than the F-35A. But the 6,500-lb. engine, avionics and cockpit are common, suggesting that the bare airframe is 25% heavier. The F-35B is 2,700 lb. heavier than the F-35A. Pratt & Whitney’s numbers, however, show that the vertical-lift system adds 4,000 lb., so the B model’s basic structure is lighter than the F-35A’s. Other differences: only the A model has an internal gun bay; the B model incorporates cavities and apertures for the vertical-lift system and has different-sized weapon bays; and B and C are stressed to 7.5g and A to 9g. One industry source sounds a warning: “The ability to keep those three platforms going, without deviating from commonality, is an extreme challenge. At the parts level, we’re hearing people say they are on the eighth design for JSF and still carrying three different parts forward for the different versions.” Three documents should provide updated estimates of the actual costs of JSF. The GAO is expected to issue its annual report on the program in March, and the Pentagon will issue Selected Acquisition Reports, which give an official projection of program costs. The FY2010 budget will also show whether USAF believes it can support 80 jets per year. The final answer: “The JET will be totally wrong and the program office will be totally wrong,” Davis says. “The real answer will be somewhere in between.” source: www.aviationweek.com |
