Colin Clark has an interesting post on DoD Buzztoday that reports of troubles with the General Electric/Rolls Royce F136 engines are causing consternation in Washington.
The F136 is the second engine for the F-35 Joint Strike Fighter, which Congress has repeatedly funded work on against the wishes of the Department of Defense -- not to mention Pratt & Whitney, purveyor of the F135 engine.
Analyst Loren Thompson of the Lexington Institute also commented on the F136 problems.
A recent "joint estimating team" finding of potential cost overruns in development of the F-35 fighter traced 28% of projected cost problems to the alternate engine. While the estimating team is probably being too pessimistic about the fighter, the prediction of a big funding shortfall on the alternate engine appears to reflect the difficulties the GE engine has encountered. A normal failure rate in development of a new gas turbine engine would be on the order of one incident every 300 hours, but GE seems to be having problems every 13 hours. As a result, it may be up to a year behind schedule on its testing plan.
This issue underscores a logical flaw in the case for an alternate engine. Backers argue that having a second engine is insurance against a design flaw in the primary powerplant being built by Pratt & Whitney for the single-engine F-35 fighter. But that reasoning works both ways -- add a second engine to the mix, and you've doubled the potential for design issues, just like you've doubled the cost of developing engines by having to fund two design teams and two development programs. With several billion dollars remaining to be spent before the alternate engine joins the fleet, there is still time to rethink whether a second engine is really needed. The Pentagon says one engine is enough.
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