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Finally...Took over a year but...

Discussion in 'Aviation Chat' started by 903L, May 6, 2017.

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  1. 903L

    903L Formula Junior

    Aug 13, 2009
    703
    S. Calif. / Arizona
    Full Name:
    Marty K
    #1 903L, May 6, 2017
    Last edited by a moderator: Sep 7, 2017
    I finally found another overhauled original JT15D-4B for my Citation SII. Just in time as my #2 engine is almost through it's 50 hour grace period. The -4B is exclusive to the SII of which they only produced 151 of. Since these engines are so rare, Pratt has converted many -4's into -4B's even changing the data plates. I only wanted an original -4B to replace my run out one. I did not want a Frankenstein airplane. There are 4B's to be found but, 97% of them are cores like my #2. Though it runs perfect, it has 12K plus hours on the core. It would be way to expensive to overhaul as many internal components would time out before the next hot section, including some T Wheels which are horrifically expensive. This baby came all the way from Chile. Now I just have to get it installed and TB will be just like new!
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  2. donv

    donv Two Time F1 World Champ
    Owner Rossa Subscribed

    Jan 5, 2002
    25,806
    Portland, Oregon
    Full Name:
    Don
    #2 donv, May 7, 2017
    Just curious-- approximately how much do you think it would have cost to overhaul your old engine?
     
  3. 903L

    903L Formula Junior

    Aug 13, 2009
    703
    S. Calif. / Arizona
    Full Name:
    Marty K
    #3 903L, May 7, 2017
    Estimates for a DAF overhaul which included replacing all my close to being timed and calendared out components, was in the high 500K plus range. The biggies were the T wheels and N1 Fan. Two things, that is a whole lot of of dough to put into an 11K+ hour 32 year old jet,and, to put into an engine with almost 13K hours on the core.
     
  4. donv

    donv Two Time F1 World Champ
    Owner Rossa Subscribed

    Jan 5, 2002
    25,806
    Portland, Oregon
    Full Name:
    Don
    #4 donv, May 7, 2017
    And that gets you 3500 hours, with a hot section in between?
     
  5. dmaxx3500

    dmaxx3500 Formula 3

    Jul 19, 2008
    1,027
    #5 dmaxx3500, May 7, 2017
    and how do you know how good this eng from chile is?
     
  6. solofast

    solofast Formula 3

    Oct 8, 2007
    1,773
    Indianapolis
    #6 solofast, May 7, 2017
    Small turbine engines are in some ways harder to design than big engines. And the cost of manufacturing parts is generally more expensive, relative to their size than big motors. It doesn't make sense since a smaller part should cost less, but because of the size constraints, the higher speeds and fact that engine length doesn't scale (the combustion system length is going to be the same for big or small engines), this impacts the diameter of thru shafts and makes for fat disks that are more expensive to machine.

    That, and the low quantities and you have a recipe for high cost parts. Add to that the fact that the engines don't last as long (it's harder to make small turbine blades with cooling passages that are as effective as in bigger turbine blades) and the costs per hour of a small engine are generally higher than a bigger engine.

    Lastly, the real culprit here is the policy of the OEM's (all of them) to rape their customers on spare parts margins. The margins on spare parts (like your turbine disks) are often on the order of 500 to 700%... At Rolls-Royce the Model 250 spare parts profits used to be on the order of $100m per year (in the early 2000's). That was more money than RR made on all of their other products... combined...

    The problem is ALL of the OEM's do it so it. Where are you going to go for a disk that they only make a dozen or so per year of??? There's no competition, and the net result is to raise prices and there is no incentive to cuts costs when you can make that kind of margin on parts. The only thing that puts a cap on this is someone who PMA's the part, and then the OEM cuts the price to below what the PMA can produce for, so the put him out of business and after that they can jack the price back up.
     
  7. 903L

    903L Formula Junior

    Aug 13, 2009
    703
    S. Calif. / Arizona
    Full Name:
    Marty K
    #7 903L, May 8, 2017
    Yes. Though the engine cost is only a part of the price. You still have to pay to have the engine removed, shipped, shipped back, and reinstalled. All new gaskets, perry seals, filters, etc... Reversers have to be removed and reinstalled, hydraulic lines replaced (not really necessary but I always do it), and so on,and so on. Oh, and if you don't want to put your plane down for a week or two, you can rent an engine which you also have to pay to get shipped to you, installed then removed and shipped back once yours is done. Learned my lesson about doing that years ago. Payed Dallas Air Motive to ship a rental engine to KBFL. For some reason it had to be picked up in Van Nuys. When it finally got to BFL, my engine repair was done. So I had to pay to ship it back to Texas without ever using it. Never again.
     
  8. 903L

    903L Formula Junior

    Aug 13, 2009
    703
    S. Calif. / Arizona
    Full Name:
    Marty K
    #8 903L, May 8, 2017
    The funds are put into an escrow account. Then many checks are made. First, was it properly preserved? It is boroscoped, ( I can never spell that word right ). If it passes that, it is put on a test stand and taken through a series of power runs. It's log books are scrutinized and component times checked. Make sure it is not on Pratt & Whitneys previously damaged and no longer under warranty list. I throw in a few of my own limitations. Never operated in a salt water environment, not off of a Govt. or Military aircraft, blah, blah, blah. When all requirements of the escrow are met, you pull the trigger and roll the dice. My run out #2 engine runs perfect. My only worry is that this new engine, only 30 hours out of overhaul, with only 3550 hours on the core, runs as well as my 3550 hour engine with very close to 13K hours on the core. I would be happy to run my #2 for another 3K hours but my insurance man says, "Nope".
     
  9. 903L

    903L Formula Junior

    Aug 13, 2009
    703
    S. Calif. / Arizona
    Full Name:
    Marty K
    #9 903L, May 8, 2017
    To Solofast,
    You are so absolutely correct. Especially about the OEMs gouging you. I can't wave at any of those bastards with more than one finger.
     

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