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  • JSF Engine "Competition" Story Rises From The Grave
    Posted by Bill Sweetman 4:32 PM on Mar 10, 2010

    Catching Consultola-specialist Dr Loren Thompson in one of his loose arguments is beginning to feel a bit unsporting, like hunting kittens with a suppressed FN P90:

    blog post photo

    Not that there's anything wrong with that.

    Thompson's latest venture is an impassioned assault on the F136 alternate engine for the Joint Strike Fighter, in the course of which he states:
    GE lost a series of competitions in the early stages of the F-35 program to rival Pratt & Whitney, because Pratt was offering a more mature design based on the successful engine built for the F-22 fighter. Unwilling to accept that setback, GE organized congressional support for its alternative...
    I thought that we had buried this argument a year ago, with a stake rammed through its heart. But since it's clearly a zombie, let's take a razor-honed garden shovel to the back of its mendacious head.

    Once again:
    The government never conducted an engine competition for the JSF. The three primes going into the JSF prototype stage, in 1995-96, made their own engine choices for the prototypes only, but time and cost constraints effectively mandated engines based on the P&W F119. And since all three prototype proposals used the F119, engine competition was not a factor in the government's down-select in 1996.

    And if you go to the original post, you'll find links to contemporary government statements (here and here) showing that a leader-follower dual-engine strategy for systems development and demonstration was adopted from the start of the program -- and also noting that P&W itself has uttered the same mis-statements about non-existent competitions.

    Why is the F135 lobby so desperate? One possibility: they need to get the alternate engine dead and buried before they stick the Pentagon with the real bill for the engine.

    The F135 is already well over budget, as this document shows:

    blog post photo
    From Navy BA-5, FY2011

    The total cost today is $7.3 billion versus a $4.8 billion then-year contract
    signed in 2001 -- a $2.5 billion overshoot and higher than the $1.9 billion overrun reported last year.  In fact, the F135 overrun is about the same as than the SDD bill for the F136.  But wait, there's more.

    In early 2007, before the F135/F136 fight reached anything like today's pitch, Pratt & Whitney was briefing openly on a two-step uprate program for the F135, as I reported in Jane's IDR at the time:

    The JSF team has already developed a two-stage plan for boosting F135 thrust after service entry. It is divided into two spirals, synchronised to the engine maintenance life
    time : Spiral 1 is due to be ready in 2014-15 and Spiral 2 in 2020-22. Each offers about a 2,000-pound thrust boost... The first step could involve a redesigned low-pressure turbine which would be lighter and would use less cooling air. The second step – which would be ready as the engines of the first F-35Bs reach their overhaul life limits - would involve a higher-airflow core, a major redesign of the engine.


    This uprating program - also reported on, at the time, by Graham Warwick - has not been talked about much since then, but  continues under the XTE68 technology development effort.

    The question is whether the F136 can deliver 5 or 10 per cent more thrust with less rework. GE has intimated that it can -- not because GE engineers are miracle-workers, but because the engine's design was frozen after the 2004 weight crisis
    .

    If the power is needed -- and the UK has repeatedly said that the service-entry thrust is marginal -- that would make a big difference to the life-cycle cost comparisons between the two engines. But if the F136 is killed off, it will be too late.

    Tags: ar99, loren-thompson

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