Even though I would rather only blog when I have “exciting” news or progress to report, I think it’s probably best that I include a lot of boring, mundane stuff too, just to keep a record of everything and also provide some help for those who are attempting to do something similar. So that’s why I’m including what I accomplished today on the SPARC.  Perhaps some of you will find it informative or entertaining.   Most probably won’t.  Today I’m going to talk about the SPARC’s seats.  Yes, you read that right, the seats.

In keeping with the over-arching goal of keeping the cost of the SPARC down to minimal levels whenever possible without compromising efficiency, performance, or safety, I decided to go with seats that are typically used for Dune Buggies.  Yes, that’s right, the SPARC has dune buggy seats.

High Back Polypropylene Dune Buggy Seat

Why Dune Buggy seats?

Well, first off, they are made of polypropylene and are tough.  They are built to be abused not only by the extreme forces and movements encountered when careening over sand dunes, but with extreme environments (direct exposure to desert sand, full sun, extreme temperatures, and water).  These seats will take a beating and then some.

Second, they are extremely light.  In order to maximize efficiency, we need to minimize weight (without compromising strength).  Each seat weighs approximately 13 lbs according to my bathroom scale.  That’s incredibly light for a high back bucket seat.   For comparison, most cheap “racing” (I use the term loosely) seats weigh about 3x as much.

Third, they are inexpensive.  I bought a pair for $70 total from a guy who had abandoned a home made Dune Buggy project.  (note to self: let’s hope I don’t follow down the same path).  You can buy them brand new online for about $60-70 each if you shop around.   That’s pretty hard to beat for something this light and durable.

But they’re hard plastic – isn’t that uncomfortable? Surprisingly, no.  They’re actually pretty darn comfortable.  The seat back is at a pretty comfortable angle, and the contours seem to fit most people pretty well.  If you like some padding anyway, I know they have padded covers that fit this seat as well.

So that’s today’s design discussion.  Like I said, a pretty mundane topic, but even the mundane is important when you’re trying to build a new vehicle from scratch.

Now back to build progress.  Today I mounted the front (driver’s) seat. That doesn’t seem like a lot, and it’s not, but it did entail finding and procuring seat sliders/brackets (~$17 + shipping from speedway motors)  and the proper bolts to go with the sliders. Because my seats are slightly different in dimensions than Kale’s seat, I had to re-drill the mounting holes in both the frame tabs and the brackets.

SPARC XEV Front View with both seats in position

There were a couple minor annoyances to overcome besides the mis-matching mounting holes. The seat slider brackets had four 1/4″ bolts welded in to mount the sliders to the frame (or maybe the seat). My seat takes 3/8″ bolts, so I had to cut & knock the 1/4″ bolts out. Time consuming, but not that difficult with a hacksaw and hammer.

The other annoyance is with the link “wire” provided with the seat sliders. Because the seat sliders have locking mechanisms on each track, there is a cable/wire provided to connect the lever that is on one slider to the mechanism on the other slider. The problem is, the wire is hopelessly too weak and too short. It’s already bending out of shape, and I wouldn’t be surprised if it broke within a week or two. I’m going to take some sturdier coat hangar type metal and replace the flimsy wire.

Closeup of the Front Seat - see the slider lever?

The rear seat still hasn’t been mounted yet, but that shouldn’t be very difficult. It’s just a matter of drilling the correct mounting holes in the frame tabs, and then bolting the seat on.

That’s it for today.  Stay tuned for more updates to come!

Eric

p.s. sorry about the low quality pics.  I used my iPhone since it was handy.