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Applying open-source tech to aviation

Discussion in 'General Talk' started by Jacob S., Nov 14, 2014.

  1. Jacob S.

    Jacob S. New
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    Hello everyone! I am a newbie to the community as of today. I figured that I would start with this forum post and see if I could get some guidance and suggestions on selecting and building the appropriate CNC mill (and possibly printer) for an open-source aircraft build that I am wanting to begin.

    There is currently an open-source aviation group, called "Maker Plane", which is working to develope a safe, reliable, two-seat, light-sport airplane which can be manufactured with open-source milling and printing technology. Their website can be seen at www.makerplane.org . The majority of the parts on their aircraft are milled from wood and other composite materials to form the fuselage, wings, airfoils, etc. Seeing their progress towards their open-source airplane has fueled my inspiration to pursue a similar project. My idea, however, differs in the fact that I would utilize aircraft aluminum in place of the wood and composite materials. The parts would be milled from aluminum sheets and formed to shape with milled hardwood blocks. For this, I would need a mill that is capable of working these types of materials while holding fairly tight tolerances. This is where I enlist the help of the open-source community. I am a certified machinist in mill and lathe operations as well as G-code programming, however building a CNC mill is a first time project for me. Any help or suggestions in getting started would be greatly appreciated!

    The following is a list of the heaviest materials that I would be working with and their dimensions. Maybe someone could give me a suggestion as to which CNC would be the best for my application?

    301 SS 1/2 hard .025" thick - 36"x 60"

    2024-O alclad aluminum .040" thick - 48"x 96"

    7075T6 alclad aluminum .063" thick - 48" x 96"

    3/4" Oak hardwood and plywood.

    I'm thinking so far that the "OX" would be the best design to go with for my application. Ideas? Suggestions? Comments? Thank you!
     
  2. slittle

    slittle Journeyman
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    Material sizing 48" x96" would be your biggest battle. Not saying its impossible but most of these builds are from 1500mm x 1500mm as the largest posted on this forum. Are you wanting to nest parts on that large of a sheet? Sheering the sheet goods close to their panel sizing would best. You could always nest smaller parts.
    From reading in these forums and following some builds the larger builds may hold the accuracy your looking for on big panel skins so far as like a fast build
    skin that cleco's right up so you can final drill, ream and rivet etc. I have seen and built and been around many kit built planes and Most skins are much smaller
    and could be done on a 1000mm x 1500mm format.
    I do not own a ox and have no experience in cnc at all. I am here to learn and make my choice into cnc and the Ox has been my favorite so
    far as a good format for what I am looking for.
    Read in the forums and go thru some of the builds and discussion's.
    Look for Mark, Twinkie and Robert and others as for the facts on the Ox.
    I hold a PPL flying for 20+ years and have built a few aircraft from scratch up, kit planes and rebuilds of crashed planes and Ultra Lights. Look for a EAA group in
    your local area and go to a few meetings as there's a wealth of skills from builders there that may own a Mill, CNC, Bridgeport etc and help.
    SS in any grade will not keep the aircraft on a weight diet. There's other reasons not to use SS in Aircraft structure also. Build to be light best advice I can give.
     
    #2 slittle, Nov 14, 2014
    Last edited: Nov 14, 2014
  3. Jacob S.

    Jacob S. New
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    Thanks for your input slittle! I have been debating with myself whether to go with a larger CNC build and nest more parts on to a sheet or go with a smaller build and nest less parts. For my current purposed project a small CNC would suffice, however if in the future I follow up with bigger aircraft builds I will have need for a bigger CNC. I would rather build one unit than have to make another down the road. Also, there might be a slight time saving element to nesting more parts.

    Rather than attempting to design an aircraft from the ground up it seems sensible to me to copy a proven design for this first project. I have kind of settled on a piper super cub as my first build. There are numerous variations of this aircraft, especially in the world of kit planes. It will have less milled parts than other aircrafts because the fuselage is mainly constructed of tube steel and fabric, but other parts such as the wing ribs and spars can be milled from sheet. CNC will greatly speed up the build process over the method of doing the layout and hand-shearing. I believe that it will also drastically reduce the cost over buying a partially manufactured kit plane. Once a part is converted from a blueprint to a CNC file, it instantly becomes available for anyone to freely download and run. This concept can be applied to other aircrafts as well.

    I am a private pilot as well. I'm not aware of any EAA group locally but I have seen a few experimental planes that are hangered at my airport. I will make a point of trying to talk to some of the owner/builders.

    On a side note my use of stainless steel would be minimal. I have a blueprint of the firewall out of a super cub that calls for stainless steel to be used in the construction. I imagine this is because of its resistance to fire and corrosion? I have attached a copy of the print.

    Good luck on your CNC search! I look forward to seeing how your build turns out once it is finished.

    Best aviation advice I've ever got - "It's not over until the prop stops turning".
     

    Attached Files:

  4. slittle

    slittle Journeyman
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    Well if your looking at the Piper then you owe it to yourself to look at the Just Aircraft
    Tube frame on a Super cub cost is crazy, welding your own will take skill and time. The last tube frame I had any to do with was water jetted
    and it came out amazing due to the owners painstaking in transferring from plans drawing to cad cam with amazing detail and very skilled machinist
    who did the jetting. We were able to tape the complete frame together on the jig table and tune for welds and spot tig in place.
    As for the stainless steel firewall, that's not a stress part. I have seen stainless used in certain parts.
    Good Luck in your plans Look for a Eaa chapter on their locator close to you. https://www.eaa.org/en/eaa/eaa-chapters/find-an-eaa-chapter

    Hey, I had had a few props stop while in flight.. it does happen
     
    #4 slittle, Nov 15, 2014
    Last edited: Nov 15, 2014

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