Flaire Project Participation

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  • Saturday, April 22, 2017 3:56 PM
    Reply # 4769903 on 3147925

    Correction, it's the Blogs button that doesn't work.

  • Monday, April 24, 2017 11:15 AM
    Reply # 4772218 on 3147925
    As much as I like BS'ing with all of you I must admit that being the only person who took part in the wing breaking who was around the airport this past weekend just about gave me cotton mouth from sharing my opinions of the experience with everyone who stopped by wanting to look at it.

    So for the rest of you , here it is. The video Bill shared is invaluable in determining the cause of the failure and we are extremely fortunate that Glenn was there with his cameras and took the time to set them up so well. I'm certainly not an expert or the authority or anything this is just my opinion of how this went down and it very well could be wrong. I'm going to refer to top and bottom in terms of how it is seen in the video. From the video the rear (auxiliary, aft, drag whatever you want to call it) spar failed first and this, almost simultaneously caused a failure in the main spar. The rear spar buckled. We all know buckling is what happens when a column is compressed to its limit. In this case the column was eccentrically loaded with much greater compression in the side adjacent to the load (ie the top in the frame of reference in the video) which is why you notice the top buckles out. There are two load factors at play here. The first is the bending this is from the load  (shingles simulating aerodynamic loads) which creates a bending moment, deflecting the spar downwards. This creates compression in the top of the spar. This compression is highest at the mid-span of the root and strut attach point. The second load is from the lifting force transmitted through the strut. Long story short, this creates compression in the axis of the spar which increases linearly from a relatively low value at the strut attachment point and is at its highest at the root. It increased like this because of the angle of the flying wire (strut). It attaches in the vertical axis of the aft spar. It should be noted that when the spar deflects from the bending moment this load becomes eccentric. I don't know if I am expressing that last part properly from an engineering standpoint but it is a factor.

    The aft spar buckled about 1/3 of the way from the root to the strut attach point. The portion of the aft spar in between each ribs acts as a beam and I think that if you were to run the numbers on this that when you add up the two loads I described above together they are at there highest in this bay.

    Since we need to wing to hold more weight we need to fix this and the fix is to change the way the spar is being loaded and also change the construction (make it stronger) in critical areas.

  • Sunday, April 30, 2017 12:45 PM
    Reply # 4792552 on 3147925

        Excellent post Matt, however, I do have to point out one glaring piece of fake news in it.  Glen’s name is spelled Glen, not Glenn.  Fake news, fake…

        It has now been several days since we broke the wing so we all have had time to reflect on what is next.  First off, it was really fun, not the fun like you have a Cedar Point but more like being tickled between the ears.  It was extreme brain fun that only takes place a few times a year on the face of the planet Earth. 

        The failure demonstrated the success of the design.  Spars are child’s play, there is plenty of data on designing and building them, has been for hundreds of years.  The questions I had were how strong were the ribs and the leading edge.  To say that I am pleased with their performance is an accurate statement.  These are the two elements of the design that are the most radical which is not to say that they are groundbreaking or innovative but rather they have never been used in conjunction as they are on this wing, at least as far as I know.

        This structure concentrates loads in the auxiliary spar, the smaller spar to the rear of the rib, that are not present in “conventional,” wing designs to the magnitude they are on this one.  In spite of this this design presents advantages that cannot be ignored so all we have to do is get the spars right because we know the rest of the stuff works.

        The good news is that we have very high tech equipment available to us to test our next aux spar design.  The Dude tested the ribs in this machine a few years ago and it proved the ribs would work.  He wrote about it in the Flaire forum and posted a video of the test being performed.  He is going to use this same machine to test coupons of of the next design.  The feedback this will give us is invaluable.

        So whats the next step?  We have to draw the airplane in Solid Works, a program I will have to learn. and I dread learning it.  We need to do this because the design is etched in stone now and we will use it to standardize the drawings for our first final design.  That is to say that there will  no doubt be changes that require subsequent  final designs.

        Once the drawings are underway will will then be able to send files to machine shops to make some of the parts for us.  We also need to finish up the tooling we designed to build the wing.  This will allow us to make the parts to assemble two wings.  When assembled we will test one of them to the design limit, not to destruction, and if it makes it we will cover it and put both of them on the airplane so we can start the test flying part of the project.

        I would like to remind everyone that this is a chapter group project and you are welcome to join in if you like.  Talk to Matt Curcio, he is the project manager.  Be advised that it takes a lot of initiative to actually get involved with this.  It is not a social event, although we have a ton of fun.  If you don’t know how to do all of this stuff we will teach you but it will take some time to become useful to the project.  I tell you this not to discourage you but, to advise you.  What would really help is to have somebody organize the operation, help keep the place clean etc.

    M  boy

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