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  • Cking
    Rank 5 Registered User
    • Oct 2004
    • 1000

    #21
    So you want to see some trijets eh?
    Hear are some pictures (poorly scanned!) taken, by me about twelve years ago. They were taken in the L.T.U. hanger at Dusseldorf, when I was out there contracting. L.T.U. as you know had a long history of operating the Tristar and loved them!. They did not think much of the MD-11. The guys there told me that they a H.F. radio problem on a delivery flight, they traced the fault to the lower H.F. antenna. On removal of the antenna the found the fuselage skin underneath it to be corroded!.This entailed a skin repair on a brand new aircraft!!!

    Rgds Cking
    Attached Files

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    • wozza
      Chelsea Fan
      • Sep 2005
      • 1089

      #22
      Originally posted by steve rowell
      Are you bashing the DC10 or it's GE engines???????
      Bashing the DC10 as a whole and its reliability

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      • glhcarl
        Rank 5 Registered User
        • Jul 2005
        • 194

        #23
        Cking,

        Are you saying the MD-11's was skin was corroded or the L-1011's skin was that was corroded? Because the L-1011's HF antenna is located at the saddle between the top of the No. 2 engine inlet duct and the base of the vertical stabilizer leading edge.

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        • glhcarl
          Rank 5 Registered User
          • Jul 2005
          • 194

          #24
          Originally posted by chornedsnorkack
          The heaviest twinjet is, I think, Boeing 777, with up to about 350 tons.

          Probably because it is not possible for one engine to propel a bigger plane. Boeing 747 and Airbus 380 are quadjets and Mriya is a sexjet.

          Can a big engine be mounted in the fin? And could a Boeing 747 or Airbus 380 derivative be built with three engines?
          Anything is possible, however is it economical or praticable. Three engines were used on the L-1011 and DC-10, because when they were designed the engines did not have the power the current engines do. Three engines were required to make them fly.

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          • Cking
            Rank 5 Registered User
            • Oct 2004
            • 1000

            #25
            Sorry glhcarl, the MD-11 was the corroded one, mind you the Tristar was a rot box too!!. That was after a few years in service. There was many-a-days over time earned on the Butt strap repairs on the belly's of the L1011's

            Rgds Cking

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            • glhcarl
              Rank 5 Registered User
              • Jul 2005
              • 194

              #26
              Originally posted by Cking
              Sorry glhcarl, the MD-11 was the corroded one, mind you the Tristar was a rot box too!!. That was after a few years in service. There was many-a-days over time earned on the Butt strap repairs on the belly's of the L1011's

              Rgds Cking
              You should have reskined the entire belly to do away with the B/L 0 Butt Strap. See SRM 53-31-00, Fig 826 Double Layer Belly Skin Repair. Butt Strap repairs only lead to more corrosion, the double layer repair makes the skin splice up on the side of the fuselage leaving a smooth surface at B/L 0.

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              • Cking
                Rank 5 Registered User
                • Oct 2004
                • 1000

                #27
                glhcarl, un-fortunately I was never on the repair team "Gravy train"!!! But I did see that sort of repair on one of the L.T.U. aircraft, it looked like an epic!

                Rgds Cking

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                • chornedsnorkack
                  Rank 5 Registered User
                  • Jul 2005
                  • 1108

                  #28
                  Extra engines

                  Originally posted by glhcarl
                  Anything is possible, however is it economical or praticable. Three engines were used on the L-1011 and DC-10, because when they were designed the engines did not have the power the current engines do. Three engines were required to make them fly.
                  But if 3 engines had the power to propel DC-10, 4 engines all underwing could have done the same. As they did on DC-8. Yet, they were not needed for DC-10.

                  2 current engines could propel a DC-10 and do propel B-777. But they cannot propel B-747 or A-380.

                  Do B-747 and A-380 actually need 4 engines, or could derivatives of them be built with 3 engines?

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                  • Cking
                    Rank 5 Registered User
                    • Oct 2004
                    • 1000

                    #29
                    There was talk a few years ago of fitting the 777 with a bigger A.P.U. and useing it as a "Boost engine" for take off, rather like the Trident 3 did. I don't know what hapened to the "talk", I assume that G.E. just pushed the GE-90's power a bit more.
                    Putting anything up high just adds expense as you need specialist access equipment to do eaven the basic day-to-day servicing. A number two engine change is a huge undertaking when you are in a warm hanger at your home base. Imagine what it's like down the line in the open!.
                    The USAF and MdC sorted the KC-10's no2 reliability out by stripping every accesory of it!. They operate the aircraft a twin and use the no2 for thrust only. I think that Fedex went down the same route with their aircraft too. I might be wrong!!!!

                    Rgds Cking

                    Comment

                    • wysiwyg
                      Retard :)
                      • Jan 2000
                      • 3749

                      #30
                      As well as the lack of suitable large powerplants several years ago there is another historic reason why the Yanks favoured the 3 engine aircraft. Many years ago in the US you were only allowed to go down to 300' on an ILS approach unless you had 3 or more engines when you could go down to 200' (assuming the ground installation was capable of doing so). This benefit helped offset some of the cost of using an extra engine.

                      Comment

                      • chornedsnorkack
                        Rank 5 Registered User
                        • Jul 2005
                        • 1108

                        #31
                        Originally posted by wysiwyg
                        As well as the lack of suitable large powerplants several years ago there is another historic reason why the Yanks favoured the 3 engine aircraft. Many years ago in the US you were only allowed to go down to 300' on an ILS approach unless you had 3 or more engines when you could go down to 200' (assuming the ground installation was capable of doing so). This benefit helped offset some of the cost of using an extra engine.
                        Plus ETOPS - the US are restricted to 60 minutes from diversion, the rest of the world is allowed to go to 90 minutes.

                        So, a central engine is difficult to service - if 2 is not enough for any reason, whether available thrust or reliability then it is better to go to 4 engines, mounting both the extra engines underwing.

                        Small planes are presumably an exception... I think that E-jets are among the smallest underwing twinjets, while ERJ-s, and a lot of bigger planes like Caravelle, DC-9/MD-8X/9X/B-717 series etc. are rear fuselage mounted twins

                        Rear fuselage quadjets are possible - I think VC-10 and IL-62 are examples.

                        So, what is the best arrangement for a small jet of over 2 engines? Tailmounted trijet like B-727, Trident, Tu-154, Yak-40 and Dassault Falcons? Or something else?

                        Is the central engine of a Dassault Falcon easy to service?

                        Comment

                        • wysiwyg
                          Retard :)
                          • Jan 2000
                          • 3749

                          #32
                          ...but 60 mins from diversion is not ETOPS, all commercial aircraft are permitted that. Many airlines are currently doing 180 min ETOPS and manufacturers are looking for longer still.

                          Comment

                          • chornedsnorkack
                            Rank 5 Registered User
                            • Jul 2005
                            • 1108

                            #33
                            Originally posted by wysiwyg
                            ...but 60 mins from diversion is not ETOPS, all commercial aircraft are permitted that. Many airlines are currently doing 180 min ETOPS and manufacturers are looking for longer still.
                            Yes, all commercial aircraft with more than one engine. But planes with 2 engines cannot go further than 60 minutes from diversion in US without ETOPS - in the rest of the world, twinjets need no ETOPS to go to 90 minutes from diversion.

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