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Engine Test loads on Weight Shift Control and Parachute Types

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  • Engine Test loads on Weight Shift Control and Parachute Types

    Hi

    Can any thinkers and experienced types out there give me their thoughts on the most practical loads to test for on a none fixed wing machine?

    Is there any difference on the actual maximum side loads experienced on a fixed to flex wing ?

    What is the implications in load test terms of removing the prop from the engine, that is just use the engine to drive a belt to a remote mounted prop.
    I presume the dynamic loading effects of the prop are potentially greater than the static mass effects?

    I also presume Section S is built around experiences and loads in a typical lightweight fixed wing or has different microlight wing forms already been allowed for?

    Thanks

    Mick
    Mick Broom
    Member 909
    Shadow G-MWTN

  • #2
    Engine Test loads on Weight Shift Control and Parachute Types

    Hi Mick,

    Take a look at Section S, Sub Section C on flight loads, especially S337 onwards, including S361 and S363. The max side
    load on the engine is taken as 1/3 of 4g, ie 1.33g.

    Also look at S561 on emergency landing loads. It's these loads that are the highest for side loads and there will be no difference between flex and fixed wing. The structure does not have to survive undamaged but it must not fail completely. By driving the prop through a belt you remove the prop loads of course, including the gyroscopic loads which can be high.

    Section S is a general guide to all types. It does not consider the particular detail of any one type.

    Ben Syson is the person to ask about prop inertia and gyroscopic loads.

    Comment


    • #3
      Engine Test loads on Weight Shift Control and Parachute Types

      Hi Adrian,

      Thanks for the reply, your knowledge is always worth tapping into.

      I have to say that the paper side of things insisting that I test for 3G sideways even if it allows for damage I will need to be convinced that its realistic and helpful . I may be completely wrong but if I am smashing the plane into a big heap the fact that the engine falls off sideways will be the least of my problems. I would take a different view on the engine passing through the pilot.

      SSDR has given the oppertunity to bring some concideration to the values I use to make the machine fit for perpose so need to understand the values expected better rather than the old way of just testing to section S.

      So what are your thoughts on the values to be expected due to the type of wing used?

      I take your point on asking Ben on the implications of the prop drive and do sometimes forget that the BMAA technical office is a very useful pool of information.

      Thanks

      Mick
      Mick Broom
      Member 909
      Shadow G-MWTN

      Comment


      • #4
        Engine Test loads on Weight Shift Control and Parachute Types

        The conclussion I have come to without any other thoughts is to test to normal side loads as Section S on the engine and forget the crash loads on the basis that we have not got the wing mass in the sums on side load.

        Will talk to Ben relative to gyro and inertia loads due to the prop to get an idea on values and take advice but think that it will have little effect on the side loads and have decided that I only need to look at forward rotation on the ground and in turbs as the prop will be solid mounted to the air frame.

        Thanks

        Mick
        Mick Broom
        Member 909
        Shadow G-MWTN

        Comment

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