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CarBEN EV open source electric car design

Discussion in 'Sketchup Gallery' started by NeilBlanchard, Jun 15, 2011.

  1. NeilBlanchard

    NeilBlanchard Member

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    I added 4" to the second piece (photos to come), and I've now glued up another 6" (sections 11-13) for a total of 4'-6" of the front:

    [​IMG][​IMG]

    The gluing is slower now because the sections hang off my table too far (as you can see) -- I need to make a table the is ~6'x6' for the middle part of the car. All 4 battery bays have started -- the outer 2 extend just 2" forward, and the center 2 extend 6" forward.
     
  2. NeilBlanchard

    NeilBlanchard Member

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    I now have three big pieces totaling 6'-2" long, and the time has come to glue two of them together!

    [​IMG][​IMG][​IMG][​IMG]

    When I placed the firewall piece on the driver's piece, I discovered what could have been a major problem: the driver's piece is warped (about 1/2-3/4") but since it still had not fully dried, I was able to use some plywood and a strap to clamp it together, along with some weights (including a 60 pound bag of cement and a large bucket of sand) and I managed to closed the gap enough -- whew!

    [​IMG][​IMG][​IMG][​IMG][​IMG][​IMG][​IMG]

    I'm going to have to build a platform and place it nose down and stack the layers on individually from now on, so that they will all be flat. I also figured out an issue I had with figuring on the actual cutting bit size in the g-code -- it was rounding up so there ending up being "extra" material all around the piece.

    I *thought* this would be a good thing to allow for some errors, but what I did not anticipate is that the jigsaw joints don't fit together very well, and the outer piece gets spread apart and it opens up the surfaces. :( I'll have to glue them later -- and all the sheets I cut from now on will have proper fitting jigsaw joints.

    And my neighbors can now see what I've been working on. :)

    I think I've figured out a way to continue the gluing process and avoid this warping issue: I will construct a level platform to have the main piece sit on it's "nose", which may have to include a support for the windshield. I'll glue the layers onto that one by one -- it will "grow" to be almost 12 feet tall by the end of the gluing process. Two people can tip it down to its "normal" position and carry it back into the garage.
     
  3. blindflight

    blindflight Moderator Staff Member

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    That's a heck of a project!! Very KOOL!!! :doubleup:
     
  4. TigerPilot

    TigerPilot Well-Known Member

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    Neal, the wrapping you get is because of the slices being only 1". I think that once you glue five or six of them together that portion will not wrap any more or did you experience it differently?
     
  5. 3DMON

    3DMON Moderator Staff Member

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    This is coming along nice. :good:
     
  6. matt_o_70

    matt_o_70 Member

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    Neil - awesome project - I love it.
     
  7. 66tbird

    66tbird Moderator Staff Member

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    Nice progress :D
     
  8. NeilBlanchard

    NeilBlanchard Member

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    The warping happened because my table was ~39" wide while the piece I was gluing was about 60" wide. I glued the first three 2" layers very carefully, and I assumed/hoped that they could then support the additional layers, but I was wrong.

    I cut 12 more sheets today, so gluing will resume tomorrow -- if it doesn't rain.
     
  9. NeilBlanchard

    NeilBlanchard Member

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    I now know what a dull bit does in XPS foam -- it melts it and flings it off in all directions! I had to pick the bigger bits out, and I think the piece it happened to be cutting will still be usable.

    [​IMG]

    A small update -- yesterday I cut 12 more sheets of foam (as I mentioned above), and today I put together a sturdy, level platform, and then glued 4" more to the big piece making the total length 6'-6". I'm going to be gluing as much as the weather allows (it is outside now) and I have to do some drafting work (for pay!) for the rest of this week.

    [​IMG][​IMG][​IMG][​IMG][​IMG][​IMG]
     
  10. kram242

    kram242 Administrator Staff Member

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    I see how your added the lip of the floor over top the battery bays, very thought out. I think I am also starting to see the makings of the window areas!
    Looking great Neil
    Mark and Trish
     
  11. TigerPilot

    TigerPilot Well-Known Member

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    Neil, the front tire has this partial off-center cover, what is it for?
     
  12. NeilBlanchard

    NeilBlanchard Member

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    Greetings,

    After I cut the rest of the sections, and glue them all together, the whole things has to get shaped -- the outside first and the inside afterward, if I can figure out how to get in there without doing damage. The foam is pretty sturdy after it has been glued together. Otherwise, I'll buy a windshield and dry fit it, and then cut out the side windows, shape the wheel openings and fit the skirts to them. Then fiberglass the outside, then shape the inside. Then fiberglass the inside -- which could be a real challenge?

    Then the foam wheels get cut off -- they are just place holders so I can see the car as it will be sitting on the road. Reinforcing gussets and plates and anchor points (and possible front subframe?) get cut into the foam inside the motor bay and the rear wheel wells. It is likely the battery bays will need long metal box channels inserted in them, to stiffen the structure. Floor panels need to be constructed and fitted.

    My intention is to use the foam as the core in a full composite sandwich monocoque structure. It will double as thermal insulation, which is a second very important function.

    Then real wheels and suspension will have to be installed -- likely the front can be from a typical front wheel drive car. The rear will probably have to be custom made to fit and work within the spaces I have designed.

    Another major area of work will be the hinges for the main hatch door and the two small rear doors, and the front wheel skirts. The hood could be hinged, or it could just be bolted in place with quarter-turn fasteners along the edges.

    Then the windshield and the side windows (which I want to have two layers of glazing) can be installed. The windshield will come from a Smart ForTwo, along with the wiper system (so if I can find a rear-ended Smart, then it could also provide the VIN).

    Then a driver's seat needs to be constructed and installed -- Dick Horowitz is looking into this for me. And a steering wheel and steering system -- I hope to find a way to use manual steering, or worst case electric assist steering. This will need to be connected to the front wheel skirts, as well.

    At this point I will have a rolling chassis! My hope is to get to this point in a year or so.

    Then the BIG step is to install a battery pack and drivetrain, and all the support systems like the charger and battery management and motor(s) controller. This will end up as a full working prototype, that I can test in the real world. This will be the lion's share of the expense, but if I have a working rolling chassis, I think there will be plenty of financial support.

    ++++

    Plan B is to use this as a mold for FRP panels around a tube steel chassis, as I seriously contemplated early on in the design process. The foam is something I am able to produce though, using the PhlatPrinter 3 CNC machine, and so I decided to do it the way I am, unless and until it becomes structurally unworkable. Doing this requires serious fabrication and welding skills, and doing the foam will provide a critical full 3D form to follow.

    ++++

    I may still make a more accurate quarter scale model for wind tunnels testing -- it would awesome to be able to say "It has a Cd of 0.XX", but it is also very important to test it full size in the real world. Crosswinds on the actual car with the actual Cg and actual conditions are important hurdles; and the actual performance on the road is the only way to really know how it will work.
     
  13. TigerPilot

    TigerPilot Well-Known Member

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    Neil, kit planes are also done with foam and epoxy layup. They do the inside by mounting the fuselage on a jig that can be rotated so that whey they layup, they always lay on the downside.

    Of course, first you do the outside, but here too it's easier if you can rotate it to lay up always on the down side.
     
  14. kram242

    kram242 Administrator Staff Member

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    I wonder if for production you could use a polyethylene rotational molded system?
    It may require partial assembly but over all I think the strength should be there if properly designed. The one that interested me was the spinal immobilizer board because it has polyethylene outer skin with a rigid foam core.
    The kayak's we use at the lake are also made this way and 'How its made' did a show on the process. It was cool and as I remember seemed to require very little plastic.
    What do you guys think?
    Check this PDF for ideas and examples. http://www.lyondellbasell.com/techlit/t ... 205717.pdf

    Attached files [​IMG]
     
  15. NeilBlanchard

    NeilBlanchard Member

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    Right, I think I'll use the 2" foam sheets I had bought to make cradles to hold the whole thing in all four positions. And I'll probably have to figure out how to rig a cantilevered scaffold platform to sit /lay on inside the car so I can lay fiberglass on the "bottom". If the outside is done first, then that adds a lot of strength.
     
  16. Evil-Tunes

    Evil-Tunes Moderator Staff Member

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    You can make a home made rotisserie like we do for the VW's using 2 Engine stands or Saw horses.

    [​IMG]

    Cheers
    E-T
     
  17. kram242

    kram242 Administrator Staff Member

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  18. NeilBlanchard

    NeilBlanchard Member

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    Why would my DWG imports from DatCAD to SU stop working all of a sudden? The export is the same as ever, and the import goes through all the steps looking normal -- but then nothing shows up... :(

    Any hints? I rebooted already.
     
  19. kram242

    kram242 Administrator Staff Member

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    Sounds to me like SketchUp may have updated and caused this?
    Try this, once you import the file (nothing shows up) try to do a Ctrl-A to select all. Than use the zoom extents tool (down by the magnifying glass) in SketchUp and see if you see it. If so from there you can explode it and it should show up.
    If this does not work you may need to re-install the older version of SketchUp.
    viewtopic.php?f=96&t=440
    This is not to say its on SketchUp's side of things, but it sure seems like it may be.
    Hope this helps
    Mark and Trish
     
  20. NeilBlanchard

    NeilBlanchard Member

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    I've tried importing older DWG files, and I've tried it in both v7 (for Windows) and v8 (for Mac), and it fails in all cases.

    I bought the updated version of VMware Fusion, which I use for running both DataCAD and the SU v7 that supports the Phlat Tools.

    This is bumming me out!
     
  21. NeilBlanchard

    NeilBlanchard Member

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    FOUND it!

    It was a corrupted arc in the DataCAD drawing that happened to be on the two GoTo Views I was exporting. A Purge did not fix it. I found it by reimporting the problem file into DataCAD, and it showed up to be a *very* long line; even though it was an arc.

    I deleted it and redrew it and all is well! :D
     
  22. kram242

    kram242 Administrator Staff Member

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    Awesome find Neil :doubleup:
    Back on track
    Mark and Trish
     
  23. NeilBlanchard

    NeilBlanchard Member

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    Some pictures of everything I've glued so far in the proper position:

    [​IMG][​IMG][​IMG][​IMG][​IMG][​IMG][​IMG][​IMG]

    I'm glad that it is not as tall as I had thought.
     
  24. theothers

    theothers Administrator Staff Member

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    Great job Neil! Very impressive. Keep up the great work :doubleup:
     
  25. kram242

    kram242 Administrator Staff Member

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    I can see the start of where the back hatch will be! :dance3:
    I love watching this project :D
    Mark and Trish
     

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