CarBEN EV5 Full Sized Prototype Construction - 5 Seat Electric Car From Scratch

[zoltanbod]

Originally Posted by ron

what a commitment I am having trouble just making a aero nose and you are building ground up ! Inspiration 1

Thanks! I see you are a hydraulics mechanic.Do you have any hydraulic drive experience?

[ron]

yep even worked for a company once called hydraulic drives ,how about you some great work on the zoleco I read about that completely some months ago

[toddshotrods]

Nice work! I do a lot of CAD/CNC foam modeling/prototyping myself. I cheat though and cut my parts in 3D slices on a ShopBot CNC router, so I don't have to do much roughing and surfacing work (lazy!?).


You have 3 axis control, will your CNC's software allow you to cut 3D? It does take an incredible amount of time though. That motorcycle body in the pic above took eight hours to cut (in 1" thick slices). The front clip on the car was also cut on the ShopBot.

Sorry to hijack - just nice to see someone else carving foam from CAD models!

[cujet]

What an incredible project, I'm impressed!

I've been involved in the composite aircraft world for 30 years. Few homebuilders put in this much effort to original form. Nice!

[bikeprof]

You guys are SUCH an inspiration...!

Maybe one day I will do something so "mundane" as putting a flat belly on my TDI, and tire flaps and..., ARGH!

[NeilBlanchard]

Yes, I could have done 3D carving in one direction anyway. One big issue though is that most of the sections were cut 2" thick because my plan was to cut them from 2" foam. But that was just not practical as the mass was too much for the X-axis stepper motor and the longest bit I could find only could cut through 1 3/4" - so I had to add tabs and cut two 1" thick copies.

In order to do 3D carving I would have had to have had a smoother model (I corrected the roughness manually in DataCAD), and I would have to cut sections every 1" and I would have had to do all the drafting work in SketchUp which would have been very unwieldy. I drafted each and every one of the jigsaw joints in DataCAD, and then copied all the pieces, and then rotated them around to fit onto 2'x8' sheets. That was months of work and I don't know how the 3D entities would have translated back and forth between SketchUp and DataCAD and then back to SU again.

The hardest part of any project, large or small, is the first part - once you get going, then it is one foot ahead of the other...

[swiftarrow]

Love it. I just got my first car a few months ago, a 1990 Volvo Brick (I'm an unashamed fan) and have been toying with the idea of turning it into a series hybrid - replacing the engine with a motor, filling the back with batteries, and getting a compact diesel generator. But first, I have to get it inspected...

Anyhow, long before then, subscribing!

[toddshotrods]

Originally Posted by NeilBlanchard

...the longest bit I could find only could cut through 1 3/4"...

McMaster has pretty long end mills - up to 6" o.l.

They have actual router bits too, including aluminum cutting bits.

Originally Posted by NeilBlanchard

...In order to do 3D carving I would have had to have had a smoother model...

Yup, that's the other downside (apart from the actual machine time) is the incredible amount of time that can be spent in CAD.

Your project looks great!

[richg]

Your car is awe inspiring, but the thing that gets me the most is where you're building it! All of my work is done in a tarp covered wood structure, it's humbling to see just how great of a project a true visionist can create in such a space.

One question I do have though, how well do you think the cabin would hold up in a rollover type accident? Is the foam cored fiberglass going to be sufficient to hold together? I only ask because I've seen several motorhome accidents that make me very leery of anything without some sort of reinforcing structure, I'm not trying to cast any disparaging remarks about your build.

Enjoy the day!

[NeilBlanchard]

Todd, thanks for the pointer to McMaster-Carr. The chuck on my PhlatPrinter 3 (which uses a Chicago Tools flexible shaft router) is small - 3/16" is the maximum shank size. And they do have a couple 4" long bits, their cutting flutes are just 1 3/8" long. This would not have worked because I need to be able to cut through the 2" in one pass - there is no digital feedback correction and any small error over say 40-50 lineal feet of cutting would cause melting on the smooth shank on the second pass.

I learned this the hard way. I even asked for a quote on custom bits from a local tool maker and they could not find a source for blanks of the needed dimensions.

One detail that will improve the rollover strength that is not obvious, is the driver's seat will be mounted on a vertical strut from the floor to the roof. And the sides are monolithic box beams continuously joined to the floor structure. There are no side doors, and there are 4 pairs of roof pillars - and the hatch door will have at least 5 and maybe 7 points of attachment (2 hinges plus 3 or 5 latches) so it should be pretty well locked in place; which will greatly strengthen the whole car.

I don't know for sure how this first prototype will do in a crash - it is a proof of concept on the aerodynamics and seating and entry door and whether or not an EV can have a 300-400 mile range and still weigh a ton or less. After I build a second one and make improvements, and build others for other people, etc. - then we will have to be concerned with official crash worthiness.