Announcement

Collapse
No announcement yet.

Pylons!

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Pylons!

    This topic is going to be on engine pylons or mounts. This will look at the development of them over the years. I will look at Boeing's.

    On the 707 you can see that the pylon goes right to the outlet. This is one of the first attempts at mounting engines below the wing.
    [photoid=5845779]
    [photoid=5802899]

    On the 737, you can see that the engine is almost handing way out front. You can see the difference from the above 707 design.

    [photoid=5765743]
    [photoid=5701409]

    On the 767, you can see that is resembles the 737. It does appear that there are different designs for pylons depending on the type of engine, as you can see in the two pictures.

    [photoid=5821531]
    [photoid=5774220]

    On the 747 you can see that the pylon doesn't "reach" to the front of the engine. It's very blunt and angular

    [photoid=5729196]

    In this picture you can see the heft of the pylons. Big engine, big pylon

    [photoid=444384]

    On the 777, you can see a very different pylon design from previous models. It more resembles the 737. It is very long and thin, with an almost upward trend.

    [photoid=5837941]
    [photoid=5750672]
    [photoid=440841]
    My Flickr Pictures! Click Me!

  • #2
    Hi Cam. Pylon design has a few main objectives.

    Firstly and most obviously is the strength to contain the forces of forward and reverse thrust of the engine in all flight regimes. Secondly they must be light weight as with all components on an aircraft yet not allow engine vibration to translate directly to the airframe. Thirdly they must allow sufficient ground clearance to avoid pod strikes and ingesting debris. This also reduces the need for taller landing gear, keeping down complexities and weight.

    Additional requirements include sufficient space for all plumbing and wiring associated with the engine. Different engines and aircraft have differing requirements in this area. Engines like the RB211 have hydraulic demand pumps within the pylon.

    The 707 you pictured has a turbocompressor mounted in two or three of the pylons, indicated by the intake at the front of the pylon.

    That's a basic overview!

    Comment


    • #3
      Re:

      ^Just to note, the advanced CFM engines for the 737 Classics were too big to be mounted in the traditional under-wing manner, ground clearance would be extremely low. So a solution was reached where the pylon was smoothly incorporated into the wing's top surface and the engines were angled upwards (thus the design for the 733/4/5 engines). The NG's have a higher ground clearance thus liminating the need for such adjustments.

      Comment


      • #4
        Big engine, big pylon
        On the B747 the pylons dont just absorb engine forces, they also house all the hydraulic components such as pumps, reservoirs, filters, guages etc etc... This is one of the reasons that they're so large.

        They've also got a large ground clearence and so they can use this to get the optimum load path for the size of engine, thus reducing the weight. On the smaller jets with similar engine power, the smaller pylons are "beefed" up somewhat due to less than optimum load paths through the frame...
        I Rule!

        Comment


        • #5
          Originally posted by AJ
          Engines like the RB211 have hydraulic demand pumps within the pylon.
          The hydraulic pumps on the RB211 are mounted directly to the engine, not within the pylon.

          Comment


          • #6
            474218, I think you might need to read what AJ said a bit more closely!

            You are correct, in that the RB211 Engine Driven Pumps are mounted on the engine (Aux Gearbox) but Hydraulic DEMAND pumps are most definately mounted in the Pylon.

            Cheers All,

            MCM.

            Comment


            • #7
              There are no "demand pumps" in the L-1011 pylons and every one of them uses RB-211 engines.

              Comment


              • #8
                Just goes to show how useful the pylons are, holding all the bits and bobs that aren't directly "stuck on" the engine, or core components.

                Comment


                • #9
                  Originally posted by 474218
                  There are no "demand pumps" in the L-1011 pylons and every one of them uses RB-211 engines.
                  Most likely because the L-1011 didn't have a need for them. whereas the 747-400 did.

                  Comparing a Lockheed and a Boeing is like apples and oranges.
                  Anybody can fly a round airplane....

                  Comment


                  • #10
                    Originally posted by N9103M
                    Most likely because the L-1011 didn't have a need for them. whereas the 747-400 did.

                    Comparing a Lockheed and a Boeing is like apples and oranges.
                    I was answering AJ's post where he said and I quote "Engines like the RB-211 have hydraulic demand pumps in the pylons". His statment is not true as the L-1011, all of which use RB-211 engines, do not have "hydraulic demand pumps" in the pylons. He made no mention of Boeing/Lockheed/McDouglas/Airbus or any other manfacture just the statement I quoted.

                    Comment


                    • #11
                      I was referring to the aircraft these guys know I fly, the 744 and 763. I apologise for not specifying that.

                      Comment

                      Working...
                      X