Kitfox Aircraft Stick and Rudder Stein Air Grove Aircraft TCW Technologies Dynon Avionics AeroLED MGL Avionics Leading Edge Airfoils Desser EarthX Batteries Garmin G3X Touch
Results 1 to 4 of 4

Thread: Load testing new undercarriage bungees

  1. #1

    Join Date
    Nov 2017
    Location
    UK
    Posts
    34

    Default Load testing new undercarriage bungees

    Hello all

    I'm about to replace the bungees on a MK2. I'm making them myself using crimp rings to form the loops.

    I'd like to test one of the loops to failure just to make sure my method of assembly is good enough.

    Anybody got an idea what sort of maximum load would be put on on a single loop?

    I'm working on (MTOW) 950lb / (number of Undercarriage legs) 2, x (Hard landing factor) 2, divided by (number of loops) 6

    ((950 / 2) * 2) / 6 = 158lb

    any thought chaps?

  2. #2
    Senior Member
    Join Date
    Aug 2016
    Location
    Melbourne, Australia
    Posts
    642

    Default Re: Load testing new undercarriage bungees

    Up the "hard landing factor" to 3 .... normal undercarriage ultimate loads are 1.5 times max anticipated service load. That way you give yourself a margin for a range of unknowns. That's typical for aircraft structures.
    David
    SS7 Builder

  3. #3
    Senior Member HighWing's Avatar
    Join Date
    May 2009
    Location
    Goodyear, AZ
    Posts
    1,743

    Default Re: Load testing new undercarriage bungees

    I made bungees for a while and didn't get too scientific when testing. I used a hydraulic transmission Jack with fabricated devices top and bottom that mimicked the gear bungee geometry. I made up a set of bungees, wrapped them to desired length then pumped up the Jack to failure. When the bungee cord itself failed before my crimps, I called it good.
    Lowell Fitt
    Goodyear, AZ


    My You Tube Channel

  4. #4
    Senior Member HighWing's Avatar
    Join Date
    May 2009
    Location
    Goodyear, AZ
    Posts
    1,743

    Default Re: Load testing new undercarriage bungees

    Thinking about my test - I used certified bungee cord and felt that the weak point would be at the edges of the swadged fittings as they could possibly damage the elastic strands in the cords. That is why the breaks elsewhere in the cord made me comfortable about the swage design and overall serviceability.
    Attached Images Attached Images
    Lowell Fitt
    Goodyear, AZ


    My You Tube Channel

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •