Aircraft Carriers II (Closed to posting)

Discussion in 'World Armed Forces' started by Jeff Head, Oct 17, 2005.

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  1. Jeff Head
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    Jeff Head General
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    Okay, guys...thunderchief in particular.

    I PROMISE you, the US Navy catapult designers and engineers know EXACTLY what they are about. They have been doing this stuff...successfully...for a long time.

    As I say, they know EXACTLY what they are doing and have left nothing to chance.

    These calculations are checked and re-checked many, many times over...and then they go out to land based facilities and test them with dead weights, and then aircraft, starting clean and moving up to every conceivable combination...and they do it hundreds of times.

    Finally, they install the same design on the carriers and then proceed to test them equally aggressively.

    You are not going to discover some error or something they "forgot," or did not take into account while talking here on an internet forum. It's just not going to happen. NOr could it. You simply do not know enough about the process and technology to do so.

    Particularly since I am certain that no one here has actually sat at the design and engineering table for these specific designs...EVER...and tried to either recreate or check exactly what they are doing.

    There is nothing wrong with questions. There is nothing wrong with trying to imagine what it must be like. There is nothing wrong with trying to figure out what calculations are involved.

    But please do not imply that they are "wrong," or that somehow they are not taking everything into consideration.

    Believe me, unless you have been a part of one these teams for a major military program in a design or engineering role...you are not even beginning to scratch the surface of all that is involved or the resources available to such a program.

    I have been in that role, albeit not on catapults.

    Trust me when I say, they know exactly what they are doing, they leave nothing to chance, they are checked and rechecked and then checked again scores and scores of times...and then they go out and test the apparatus hundreds of times on land before even considering taking it to sea for the first time....and then that too is to test a lot more, and test again and again before it ever even approaches operations.

    Can something still fail? Of course. The material is not perfect, no matter how much you put into it. This is very high performance stuff meant to operate in harsh conditions.

    But it will not be because the absolute best minds were not on it, and not because they took something to chance or forgot something.

    Almost invariably if something like this fails, it will because someone operating it makes a mistake...or takes a chance (and in serious combat situations, they may determine that they have to take such a chance)...or because some piece of it failed due to imperfections within it.

    As a result of all of this...I tell you now that the F-35C is going to operate very well off of EMALS, and in all conditions with all sorts of stores...up to and including being completely loaded out. And it will end up doing so tens and ultimately, hundreds of thousands of times.

    Carry on.
     
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  2. Jeff Head
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    Jeff Head General
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    Aksha, your last pic shows the Vikramaditya and the Viraat...once again...operating together.

    It reminded me of this pic that I REALLY like of the Vikramaditya and the Viraat carriers operating in formation together. Beautiful picture and quite the accomplishment for which the Indians can and should be proud.

    [​IMG]

    Two fixed wing carriers operating and in service together. A very exclusive club.
     
  3. Jeff Head
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    Jeff Head General
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    These three pictures show the great diversity and capabilities of the US Navy's large LHDs (and LHAs):

    First, Air and Amphibious Assault centricity:

    [​IMG]

    Second, a strong fixed wing air support capanbility

    [​IMG]

    Third, operating as a completely dedicated fixed wing carrier:

    [​IMG]
     
  4. strehl
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    strehl Junior Member
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    There is nothing that can be said or referenced which will convince anyone who is predisposed to dismiss official Navy statements as lies or evasions. All references on catapult performance that I can find indicate launch speeds are indeed in the 145Kts range as indicated in Jeff’s original table. This goes for unloaded as well as loaded aircraft.
    My non-conspiratorial adding of the facts is that catapults are controlled such that the mass of the aircraft and load is compensated by changes in catapult force levels resulting in an exit speed always in the neighborhood of 145Kts. Throw in the carrier’s speed and we get to around 175Kts. I have also found various references indicating stall speeds of fighter aircraft are in the neighborhood of 90-110Kts. Adding in fuel and weapons would increase that speed. However, I believe 175Kts is above the stall speed of even a maximum loaded fighter and if not, then there will be a mild sink rate until speed is built up with the engines at full power or afterburner.
    It is frustrating that articles specifying exactly how catapults are set for acceleration force and exit speed are not readily found. It would eliminate a lot of unnecessary argument.

    I look forward to seeing this level of disbelief if and whenever China launches a catapult equipped carrier.
     
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  5. Jeff Head
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    Jeff Head General
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    As I said earlier (in my last post), this stuff is well understood by the designers and they check it ad infititum...and then test it hundreds and hundreds of times.

    Detractors and those who somehow believe they can second guess or better calculate than the people who have been doing this for years (decades in many cases) are whistling past the graveyard.

    You are not going to see any such specifics in the open/free domain. Even steam catapult critical details are a closely held secret. They enable potential adversaries too much capability for any nation that has them to simply give them away.

    We know basically how they work, and we know some parameters...most of which are self evident and easily obtainable by simply looking and watching.
     
  6. thunderchief
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    thunderchief Senior Member

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    Yes, and this is more or less tolerable even with steam cats . Problems appear at higher speeds .

    Engineers do make mistakes. Airplanes crash, ships sink , shuttles explode. They are not gods .

    In this case, they have discovered own mistake . We could just make educated guesses what is it (and this is one of the purposes of this forum) . But, there were many examples in history of engineering when simple people , sometimes uneducated, uncovered major flaws of big systems .

    Free men do not believe government unconditionally . They use their God given right and privilege to think, doubt and investigate . In this case, I have my opinion which I tired to prove as best as I could .
     
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  7. Jeff Head
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    Jeff Head General
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    I never said or implied that they did not make mistakes. In fact I also said that bad things happen.

    Neither did anyone say or imply that they were "Gods" or anything like it/.

    If they were...they would not need to be checked and re-checked many times, and would not need to test their work hundreds and hundreds of times, would they?

    What I did say is that I know something about what goes into these projects and the level of experience, education, professionalism and absolute commitment to ferreting out issues that is involved.

    Go ahead and apply whatever level of scrutiny you wish to what they are doing. Do whatever calculations you can think of.

    That is all fine and I would not discourage it.

    But get a little perspective and ensure that there is no inkling of an attitude that somehow her eon SD we are going to discover things that they left out or forgot in this area of expertise, or reveal any part of this that they have not considered and already gone over it all with a lot of experience, very specific algorithms, and detail than we can possibly imagine or have time for.

    That simply is not going to happen. And, if I as an individual feel that some level of that is creeping in, I will use the same God-given right to call it every time.
     
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  8. Air Force Brat
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    Roger That!
     
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  9. Jura
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    Jura General

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    also non-conspiratorial is my suspicion that thunderchief oversimplified the model
    (which would not lead to just a = v*v/(2*S) I posted above, but ... would implicitly depend on the applied force maybe? in the way unknown to me though :)

    had (and I sure don't think this had happened!) too short deck been designed, it would've been the biggest oops since 1938: https://www.sinodefenceforum.com/uss-missouri-bb-63-iowa-class-battleships.t7187/page-2#post-325762
    (the turrets which could not accommodate the 16" guns ready for them -- I facepalm LOL)
     
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  10. FORBIN
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    FORBIN Lieutenant General
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