This area will be filled with all types of documents but for now it contains all of the 3D and 2D files for the parts and assemblies created to date.
The 3D model is created in Solidworks (or any CAD program) by creating parts (sldprt), then mating them together in an assembly (sldasy). Pictures of each are made by generating .jpg files, and drawings (slddwg) are made so that the 2D cutting files for CNC cutting can be made (.dxf).
Vectric Cut2D accepts the dxf files so that the material thickness, cut depth, cut speed and tool path can be defined, from which G code (.txt) files are generated. These are used to run the CNC machine.
ZWheelz Open Source
Electric Kit Car Design
Center Bulkhead (CB)
The CB is about 7" thick (14 layers of 13 mm panels) at the widest portion where the upper control arms mount. Two CB0 parts are the largest in the center and are the foundation for the symetrical layers to each side. The lower control arm is off center and non-symetrical layers create this area which is not shown yet. The subsequent layers are CB1 through CB6 getting progressively smaller as they move out from the center. The lower section also contains vertical slots for the frame rails to fit into. CB0 has a cutout for the upper shock mount (center 1") and all other layers have a hole in this area for the shock mount bolt tubes.
CB0 through CB6 parts.
The frame rail spacing is set by the battery pack based on 96 x CALB 100 ah cells right now. Different packs will be created to look at different configurations.
Since the front end points are basically fixed (based on the MII front end with the 2" steering extensions to make it 60" track), the outer frame rails need to fit in the area between the control arm mounting points. This necking-down of the side rails looks like a weak point so three options exist (or the fourth option of leaving it as-is if it is strong enough).
Option one is to look at different battery pack configurations. Option two is to split the side rails to form a "Y" shape with an upper and lower section going through the CB and leaving a space for the upper control arm. There is plenty of space above the Upper Control Arm (UCA) mount to create another slotted area for the upper side frame rail. The third option is to move the control arm and shock mount points out. With this option, the frame rail still has to pass over the Lower Control Arm (LCA) and allow room for LCA travel so this is not a great fix but I like the idea of widening the front end to improve stability but that will require finding a new rack or adding more extensions.
I just made a zip folder for now with all files. Creating a directory with individual files will take a while. I still need to sort the file types and clean out some older files.
To be done;
- finish jpgs for other parts
- create more battery packs
- make a scale figure 6 feet tall to show driver position.
- expand frame rails to be 4" thick (8 layers) verses the 2" thick (4 layers) shown in the current model. This is probably massive overkill but until some analysis is done it seems like a safer route to the first prototype.
- draw swingarm. A machined aluminum plate is planned for the swingarm mount.
- draw bicycle/motorcycle frames to show concept for frames, forks and swingarms.
Some possible battery pack sizes in the Excel spreadsheet below for the two drives listed. A Warp 7/Warp 9 and Curtis/Soliton would also be options but are not listed yet.. A 300 volt pack for the 40kW BLDC (using 96 x CALB 100 ah) and a 76 volt pack for the AC50 (using 24 x CALB 400 ah) happen to be close enough in size to use the same frame rail spacing. The low voltage is desirable from a safety viewpoint and may provide adequate power for a lightweight vehicle. The 200 ah cells could be used for the Warp motors and it may be worth looking at a 12" spacing to accomodate these cells. They are actually the 180 ah cells so the dimensions need to be verified.
An initial configuration was added at the bottom of the spreadsheet to show weight (1260 lbs) and cost ($21K) for a 23kWh pack of CALB 180 ah at 115 volts and an AC-35 drive system. This looks like a good start and seems like a good balance of cost and performance. Since it's a very simple WAG at cost and weight, it is more likely to be about 1500 lbs and $25K for a 100 mile range vehicle. The smaller pack will allow for narrower frame rail spacing and lower cost and weight, as well as a lower system voltage.