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  • Aluminum

    What would you guys recommend as a good material to build an HMV car? I know i posted here previously about high mileage vehicles - the goal is to make a super efficient gas vehicle (essentially a go-kart) and i've been looking around at aluminum. I'd really like to find the dream alloy - cheap, easy to machine and weld, and super lightweight. I know there is no such thing but what kind of recommendations do you guys have? I don't think i have a particular priority as to which quality i'd preffer - i guess the cost is the biggest issue at this point. Thanks for any input!

  • #2
    FT, try to find Upsadasium in larger quantities; all I can find are "Billets" of 2.546oz., so it would take quite a few even for a go cart. I like the anti-gravity properties. Keep up the good work.


    • #3
      All materials have trade-offs. Aluminum - for all the qualities you listed, but did you ever squash an aluminum beer can with your bare hand? I know that cars, like airplanes, are not supposed to crash, but what if...?

      Most people (other than bikers) perfer to have a little mass around them for safety.

      Seems these days that cars are subject to conflicting requirements; transport yer carcass from point a to point b, but cocooned in safety, in air conditioned comfort, entertained, informed and with convenient cupholders in any and all possible positions. I maintain that drivetrain efficiency has reached a plateau and now the automakers add cupholders and entertainment items to "improve" the vehicle.

      Twern't much help, mostly rant. Sorry.
      Last edited by Weston Bye; 05-01-2006, 05:01 PM.
      Weston Bye - Author, The Mechatronist column, Digital Machinist magazine
      ~Practitioner of the Electromechanical Arts~


      • #4

        AZ31B-H24 will give you lightweight, easy to weld and a joy to machine. Sorry about that fourth thing.


        • #5
          All I will say is Aluminum alloys like the steel alloys we work with are made with differant properties in mind. Depending on there use.

          There is no one alloy of aluminum that is perfect for everything. Niether is there one kind of steel, brass, whatever.

          Study the properties and uses of the most common sorts. They are the cheapest and therefore most available.

          Look up, the 2XXX, 5XXX, 6XXX, and 7XXX series.


          • #6
            Fastrack, check the Formula SAE rules regarding materials. This is the guide for all the university teams that get involved in building the Formula SAE race cars and you probably would be doing basically the same thing. Here is the Formula SAE website and the PDF of the rules:


            • #7
              I just had a look at the regs. The roll bars must be steel, no exceptions. The rest can be what you like but you must supply information and documentation as to the strength equivalent to specified steel sections.

              I would use graphite epoxy spars for many of the components. They aren't extremely expensive and are readily available as power stunt kite spars in sizes big enough to be useful.
              Free software for calculating bolt circles and similar: Click Here


              • #8
                wow the sae competition is pretty intense - ours only requires three wheels, a body to enclose driver (can have open or closed style cockpit) a roll bar of any material that can handle a static load of 280 lbs, kill switches, a 50 foot turning radius, ability to stop from 15mph in 15 feet (or something like that) and the vehicle must not tip w/ driver and vehicle at some degree incline (again can't remember specifics).

                Evan- i like the idea of the graphite epoxy resin - a team this year used graphite resin poles to form there body; the deflection in the poles allowed them to form some really nice curves. After everything was in place they covered it with monocoat. That stuff really works great for the body - we've been using some similiar stuff donated to us by a place that uses shrink wrap to store boats over the winter.

                p.s. where can i find that upsadasium? Anti-gravity sounds like a pretty sweet idea...


                • #9
                  A good place to start is the "Racer's Encyclopedia of Metals, Fibers and Materials" by Forbes Aird and published by Motorbooks International.

                  Border's, Barnes & Noble maybe even Amazon will have it.


                  • #10
                    Great! Thank you for the suggestion - this kind of leads me off on a tangent which i may post as a thread later on, but anyone have any suggestions for good reading/reference material for designing cars, engines, etc? Any kind of Audel's type handbook for racing? That would be awsome; i've looked around at the local book stores but haven't turned up anything besides Monster Garage Weld Anything and etc type books.


                    • #11
                      If they were able to deflect graphite epoxy rods they must have been using tiny sections. Don't confuse it with the same looking fiberglass epoxy resin rods. Graphite epoxy hollow tubes are incredibly lightweight yet incredibly strong and stiff. I used .5" tubes with .030 wall on my telescope for some of the truss. On a length of 2 feet supported on the ends with a one kilo weight suspended in the center they deflect about .010" but only weigh about 30 grams.
                      Free software for calculating bolt circles and similar: Click Here


                      • #12
                        Engineer to Win by Carroll Smith
                        Any other book by Carroll Smith, like Prepare to Win and Tune to Win

                        How to Make Your Car Handle by Fred Puhn
                        Chassis Engineering by Herb Adams

                        Engines are a broad subject, but a good book with a fair amount of explanation as to why certain modifications help is Power Secrets by Smokey Yunick
                        Location: North Central Texas


                        • #13
                          Evan - yeah i did a little research online about graphite epoxy rods and realized that they must have had fiberglass. Shoot it all looks the same to me

                          Joel - Thanks for the recomendations; those will go on my growing wish list of tools and literature!


                          • #14
                            "Carroll Smith's Nuts, Bolts, Fasteners and Plumbing Handbook"


                            • #15
                              Machine it out of heliuminimum. This metal is very easy to work with except that you have to vacuum the chips off the cieling. Care must be taken. Don't let go of the part when you are outside. You'll never see it again.