LMA Build in the UK, to SSDR spec.

Discussion in 'Tube and Fabric' started by flywheel1935, Jun 1, 2019.

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  1. Aug 27, 2019 #21

    flywheel1935

    flywheel1935

    flywheel1935

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    Hi Percy, had an email from Cliff, Freds' son, a week or so back. To be honest he didn't really give me much info, apart from "possibly" getting more involved with the LMA
    website ???? but despite several other "interested parties" ??? posting emails, nobody has heard back from him ,yet !!! I am going to sail my own voyage on my build, as there is some
    poor design elements that simply need to be addressed, then redesign the airframe ,so that UK sourced materials can be used. Cliff did say that after a while, I guess early 90,s
    that the Alloy tube used 1/2" x 3/4" x 0.035 6061-T6, was no longer available, so left it to other LMA builders to use what they could find ????? . Nick Onn was 25th at the WAC in France
    yesterday, with one more routine to go. I'll speak to him soon, Alan.
     
  2. Aug 28, 2019 #22

    pwood66889

    pwood66889

    pwood66889

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    There is an LM-5-XW available for $17,500 in Texas... :) Comes with an O-200 that has "been run monthly."
    Am seeing if there could be some manuals available from him. A couple quid for a point-pdf would be worth it for me.
    What would be the URL on the "LMA web site?"
    As to "poor design elements," Fred just scaled up the Real Thing.
    Percy
     
  3. Aug 28, 2019 #23

    flywheel1935

    flywheel1935

    flywheel1935

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    Hi Percy, heres the LMA website> https://groups.yahoo.com/neo/groups/LMA_builders/info

    Regarding 'poor design' !!!! key components such as the landing gear and wing lift strut points, are extrusions that have to be mounted on top of rivet heads
    that hold the Airframe gussets in place, I,ll post photos. I'm guessing that you and Fred may well have been friends ???? but I've yet to come across
    decent aeronautic solutions to the kit build, looks like each and every model was a modification of the previous model , hence the confusing array of builds available.
    He would have done a huge favour to the the 'Kit Plane Industry' to develop and fine tune 2 or 3 models, and get them correct. Even the hardware in my kit is wrong, as grip lengths and nominal lengths
    have been mixed up, so the recommended bolts,(as per the build manual) are either to long or to short, by the threaded portion, !!!
    I may come across as being critical of the LMA kits, but unless you've IMG_1904.JPG built one, especially the metal airframe then I feel justified in my thoughts.
     

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  4. Aug 30, 2019 #24

    PTAirco

    PTAirco

    PTAirco

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    Looking at the right fuselage side, it appears the is no real triangulation around the door frame. I know you need a door to get the flesh servo inside but I would add some tubes and gussets to make that area take its share of the load. Right now you have an unbraced polygon there. And yes, I'm sure it works but it wouldn't take much.
     
  5. Aug 31, 2019 #25

    flywheel1935

    flywheel1935

    flywheel1935

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    Hi PTAirco, yes, these are the design issues that keep appearing !!!!, one of the first times I realised the design was flawed was checking the loading point for the undercarriage.
    Logic says it should use the same load path as the wing pickup points, ??? but the rear pickup turned out to be mid span of the lower longeron, no loads should be mid-tube, but at a nodal point.
    I will be beefing up the door opening, and added a 'hardpoint' at the rear landing gear pickup.
     

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  6. Sep 1, 2019 #26

    dino

    dino

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  7. Sep 4, 2019 #27

    pwood66889

    pwood66889

    pwood66889

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    Thanks for that LMA group link. May have to squint around.
    Did contact one person with an LMA for sale. He had no books, and shared a hand-drawn part. Very thin gruel.
    I would not say Fred was a "friend." Just that I am a "Social Butterfly" and am keen on airplanes. I visited him one time because he was close. Then my job transferred me where a person was that had offered him a place on his air field in New Mexico. We did correspond at length.
    I believe Mr. Fred was trying many things to gain commercial viability. Perfecting a design was probably not his style. I appreciate his innovation with the square aluminum frame, but do grant your construction points.
     
  8. Sep 5, 2019 #28

    pwood66889

    pwood66889

    pwood66889

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    Saw another LM1 (Cub-a-like) on the market. PM'd seller asking if had books.
     
  9. Sep 5, 2019 #29

    flywheel1935

    flywheel1935

    flywheel1935

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    Hi Percy, think your starting to see my point !!!! As Fred used 3/4" x 1/2" tube, at every gusset, ( bearing in mind this is a 'Bonded' Airfame ) 33% of bond area is lost on the 1/2" side !!!
    We used 3/4 x 3/4 for our rear longerons, so bond area is equal at each join. No stress measurements were supplied to the UK/Eu importer, so that killed sales this side of the pond.
    Its also not a "Quick Build" there are close to 250 gussets in the build, from design to manufacture + cleaning, deburring, fitting, drilling, bonding then riveting ! Its close to 1 hour of gusset time, for each one, theres already 250 hours ish. Anyway as Ive got plenty of spare time,and a free airstrip and Hangar I'll just plod on with the build. !!!
     

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  10. Sep 6, 2019 #30

    pwood66889

    pwood66889

    pwood66889

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    Stress measurements do not seem to have been Fred's style. And any measure was so prep dependent that I doubt if 2 could be close hand running.
    His innovation was going with square tubes and bonded construction in the first place. Others, like the LePelican, used round and bolted. Not my idea of good joins between members. I can send you pictures of what LePel had to do to make the joints any where solid.
    And yes, the gussets had to be one-off for each join - perhaps 2 if the other side matched well enough.
    There seem to have been a few LM airframes come up on sales sites I get. If one was close enough, and cheap enough... Percy
     
  11. Sep 13, 2019 #31

    flywheel1935

    flywheel1935

    flywheel1935

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    Just come across another poor design element !!! as the wing roots are different lengths, due to the cockpit being tapered, ie; 36"
    wide at the front spar, and 33" wide at the rear spar, the brackets that hold the "root spars" are now at an angle of over 90deg, so theres a tapered
    gap at a major stress point......( Percy, if you see a cheap LMA, run a mile). We are going to redesign over the winter a new "parallel " fuselage, and use the current one
    only for trial fitting of controls, etc.
     
  12. Sep 14, 2019 #32

    flywheel1935

    flywheel1935

    flywheel1935

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    IMG_1943.JPG This is the main wing compression to fuselage bracket !!!!!
    just can fathom out why FmcC of LMA designed it this way, seems looks overtook engineering skills :-(
     
  13. Sep 17, 2019 #33

    flywheel1935

    flywheel1935

    flywheel1935

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    Going to redesign above bracket, and incorporate a "Wing Fold System", as per 'Kitfox' style aircraft. Mocked up system and seems to work fine, just need to machine
    hinge from alloy billet, then look at "parallel" fuselage, "Skunk Works Nofolk" !!!
     
  14. Oct 1, 2019 #34

    flywheel1935

    flywheel1935

    flywheel1935

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    Update. Were going for a 'wing-clip' loosing 1 bay per wing, or 8sq ft of wing, just to get a bit more load, + Wing fold, so we a road trail it, and save on hangar space and cost,
    pics to follow soon, watch this space.
     

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