Sunday, March 30, 2008

Two British Lightweights

When I started researching for my locost build, I'd never seen a real Seven in the flesh. As of the beginning of this month, the closest I'd ever come was checking out Andrew's build-in progress. Fortunately, in the last month I've gotten to check out my two favorite cars (and biggest inspirations) in the, metal. Both experiences were carried out with huge child-like grins!

First up was an honest-to-goodness Lotus Seven Series II that I caught at the 2008 12 Hours of Sebring. Actually, there were two of them - a racing and street version. These cars are owned by Paul Stinson. He races the high-output version in the SVRA and SCCA. The street car is his golf-cart substitute for commuting around Sebring!

He was kind enough to let me sit in the street version, which reaffirmed my need to lose weight or build a larger chassis. I was able to catch the car on video as it went out for a recon lap of the Sebring infield.

The best photos I took of both Sevens are up on my Flickr site.

The other car is the ultimate evolution of the the light-and-agile Seven. The Ariel Atom is my favorite car. If I won the lottery tomorrow, I'd drive to pick up my check in this bad boy. This particular Atom was parked nonchalantly at the 2008 Georgia Tech Auto Show.

I could have stared at this car for hours, but I was taking care of my daughter and had to look fast (fortunately pictures last longer). There are so many fantastic details, so many awesome welds and crafty bits of carbon fiber! Everything clearly had a lot of thought put into it. Even if my Locost doesn't go as fast as the Atom (which it certainly won't), I hope that I can put as much effort into the design and construction of my car as the folks at Ariel do in theirs. It's really a stunning car.

The Atom at the show was for sale for the cool price of $79k. It's tempting to sell our house and buy it, but since there are no body panels and no roof it wouldn't be very good to sleep in.

Both of these cars capture everything that is good and holy about sports cars. They're light, agile, responsive and provide the right medicine to treat the current pandemic of bloated, overweight and overwrought sports cars. I hope my locost comes close to their awesome example.

Thursday, March 27, 2008

Starting to lay stuff out

The time has come to start to put things together with the design of the Spartan. I've reached the point where I've got far too many ideas for the frame and layout and it's becoming difficult to keep them coherent in my head.

I work with CAD every day (Pro/ENGINEER to be specific), so I can get quite a lot done during my lunches at work. Fortunately, the software is flexible enough that I can lay out a tremendous amount of detail before actually having the critical components in hand.

The chassis started as a Gibbs chassis, but I've already made several mods, most notably reducing the length 2". I think the Gibbs design is pretty long, and I'd like to get the wheelbase down to 95"-98". I'll post more about the frame once I get the preliminary design done.

The components are rough models based on pictures of the actual components and a few key dimensions. Already I'm pretty concerned by how big the stock Miata intake manifold is.

For right now, though, this will give me enough information to pick components and place them in the car. I'm hoping that I can do an accurate enough job to reasonably predict the CG of the car and do some tweaking. Eventually I'd like to have a very accurate model of the entire car.

Besides, frame development in CAD is cheap and easy. I have access to FEA software, so I intend to model the "stock" Gibbs chassis and compare it to my evolved frame so I can get an idea if my ideas will work or not.

Tuesday, March 18, 2008

2008 12 Hours of Sebring

Last weekend I made my first trip to see the ALMS 12 hours of Sebring. What a blast! The racing was excellent and both the starting grid and the infield were full of awesome cars.

I didn't realize that it was spring break, and we made the mistake of camping in the middle of 20,000 drunken college students. That doesn't make for good sleeping. The facilites at Sebring are also atrocious, so I think the next time I go to the race it will be in an RV.

Here's a GT2-class Corvette heading out in the morning for its recon laps. While the full-power GT1 cars are neat, GT2 is where it's at. There is so much diversity in the lower class this year and it makes for pretty awesome racing, even if some of the newer cars are moving chicanes.

The biggest reason I wanted to go to this race was to catch the only North American appearance for Peugeot's LeMans diesels. Even though they dropped out early, they're still stunning cars and a lot of fun to watch.

I've posted the best of my pictures on my Flickr site. Here's a slideshow:

Thursday, March 13, 2008

Atlanta area Locost builders' meetup

Last weekend I met with several Atlanta builders to introduce ourselves and chat about Locost stuff. We all had a great time, and it was nice talking about the car with a group who are as passionate about building a locost as I am.

Additionally, I finally got to sit in a Locost/Lotus/Caterham sized frame (thanks eVox!). My first reaction is that the car is tiny! Unless I give up lateral support in the seats, I think I'm going to have to widen the frame to fit my physique. I'm trying to lose as much weight as possible before starting my build, but even then things are going to be tight.

I'd been resisting building a plus sized frame for some time, but I do think something's got to give. The Gibbs chassis is a +221, meaning it's 2" wider, 2" longer and 1" taller than the earlier Champion design. I think the extra 1" per passenger will make a big difference.

The extra width would also come in handy in the driver's footwell. It's a little tight, especially with my clod-hoppers on. I may have to invest in a pair of driving shoes.

No matter what, sitting in a mostly completed frame underscores the need for some kind of seating buck to simulate the passenger compartment of the finished car. Better to find out I don't fit before I start cutting metal...

Wednesday, March 12, 2008

The Spartan 7

Naming my daughter wasn't that hard. Naming my car has proven to require much more thought. I'm not exactly a major manufacturer, but this name will stick with the car throughout the build, and I feel like it needs something a little better than "my locost".

I wanted a name that was serious, without being too stodgy or ridiculous. The "Conway Superturbo AstoCaster XD6" may sound cool to a 6 year old, but it just doesn't fit the car I'm designing and building.

So I'm calling my car the Spartan 7.

The name evokes a certain aggressiveness and purity of spirit. Maybe I've watched 300 way too many times, but I think the name relates the Seven's hard-core philosophy. It also conveys the minimalist ethic so important to this kind of car.

I plan on creating nose and tail badge artwork for the finished car. I'll post them here when they're fleshed out.

Tuesday, March 11, 2008

Some thoughts on safety

"Do you ride motorcycles because of their proximity to death, or in spite of their proximity to death?"
This was the opening question posed by Matt Chambers, CEO of Confederate Motorcycles, during a recent presentation on American design.

I don't ride motorcycles, but if I did I'd have to answer "in spite". I'm lucky in that I have an abnormally high sense of self-preservation. I usually lift off the throttle well before the limits of my car and I always instinctively slow when rounding a blind corner. That's why I'll probably never be a great racer, and why I pay next to nothing for insurance!

I'm a father and a husband, and I don't particularly want to get killed or maimed for my hobby. Worse, I don't want to take someone out with me. So when a recent discussion with co-workers turned to the subject of the safety of my home-built car, it led me to make a few more decisions on what my car will be about.

I don't expect this car to be as safe as a real car, period. I plan on using 6-point racing harnesses, but I won't have airbags, ABS or even side-impact door beams. If I get t-boned by an Escalade, it'll probably put me in the hospital (or worse). I take my safety seriously, but I also lament the time where cars weren't loaded down with 1000 lbs. of safety features. I'm starting to get fanatical about weight, and a line has to be drawn between safety and the purpose of the car.

That being said, the primary approach I'm taking with regards to the safety of the vehicle is to prevent a loss of control of the vehicle or dangerous vehicle dynamics while on the road. I'll have to practice "active safety" (aka paying attention and driving defensively) with regards to threats from other vehicles on the road.

To me, loss of control usually falls into 3 areas: structural failure, loss of brakes, and loss of steering. There's also the terrible threat of a fire.


Carroll Smiths "Prepare to Win" is an awesome book, and I think all builders should read it. It outlines his fanatical attention to car preparation to minimize mechanical failures. I won't go over all the details covered, but here are a few "high points" I'll focus on during the design and build:
  • Use aircraft grade hardware to secure anything that'll hose you if it fails. Lock washers, nylock nuts and loctite just don't cut it.
  • Safety wire or cotter pin all hardware that may vibrate loose.
  • Redesign stress points (like suspension mounts) to maximize weld area and to prevent loading welds in tension. This is a major issue (to me) with the current Locost design.
Additionally, I'm planning on integrating the roll-bar into the frame (like Moti did on the LocostUSA forums). I'm not really impressed with the way the roll bar mounts on the current Locost design.

Finally, I just need to pay attention when designing and building the suspension. I don't plan on cutting corners with the structural integrity of the suspension bits and mounting points.


Mark Rivera's crash at Mid-Ohio really opened my eyes to what could happen in my car. In his case, a fastener worked free on his brake pedal and he lost brake control.

Thankfully again he was on a track with enough run-off to contain the accident. My worry is that my car will careen out of control on the street. I've made a few decisions regarding the brake system.
  • I'm going to use a commercial pedal set w/dual cylinders. I don't want to make my own when so many proven systems are out there.
  • I intend to run brake lines away from heat and sources of puncture. The brake lines to the rear will have to run past the driveshaft, so I'll have to think of a way to protect them.
  • I'm going to run hanging pedals, if possible. As one commenter on the LocostUSA forums pointed out, hanging pedals are less vulnerable to debris clogging the works.

There have been many posts on the forums concerning steering rack modifications to reduce bump steer. I get the willies when I think about welding my steering rack. Especially because once welded and reinstalled, there's almost no way to quickly inspect the welded area over the life of the car. If at all possible, I'd like a professional solution, either an off-the-shelf rack or something modified by a pro.

I'm considering using a removable steering wheel, but I need to do some research regarding the safety of these on the street.


This really scares me, and it should scare everyone else, too. It's going to be friggin expensive, but I want to use a real fuel cell for my car. I intend to mount the cell in the rear above the differential to give as much crumple room as possible in the event of a rear impact.

I'm going to have a fire extinguisher in the passenger compartment and battery cutoffs on the dash. I intend to run fuel lines in the same "protected" zone as the brake lines.

In closing, safety isn't just a punch list of features, it's a design approach. As I design and build this car I'm just going to have to be diligent about building something fun and light, but not dangerous.

Monday, March 3, 2008

Happy Birthday to Me!

Awesome! My birthday present just arrived - a 900 page, 10 lb. epic work of automotive design philosophy and practice (and its companion workbook).

This isn't exactly light reading, so I imagine it'll take me awhile to go through it. At first glance it doesn't seem too daunting, at least compared to some of my engineering textbooks. I know that it's referenced heavily wherever vehicle analysis is discussed, so I'm looking forward to reading it!

I know, I'm a dork.

Here's a locost tip - get a friend who's in the SAE to buy it for you. The set is 25% cheaper to members.