29 Jan 2012

The windscreen frame is coming along pretty well, the aluminum frame still needs the welds ground flat. Next is fabricating the bottom support along the cowl and making the threaded mounts, but it turned out okay (making things easily removable really slows down the “just get on with it” mentality.) Not sure what color to make it, the same color as the chassis so that it blends in, or perhaps the same color as the suspenion arms? Meh, we’ll see. Anyhow, after that’s done it’s back to the passenger seatbelt mounts.

Regarding visitor locations, with currently 45(!) countries, it’s surprising that there hasn’t been one visit from the most populous country in the world – China. I wonder if it’s the language barrier, no one is interested in building cars, they aren’t allowed to build cars, or is it due to censorship? Just curious.

22 Jan 2012

Slight change of plans. While drilling holes in the windscreen makes mounting it straightforward, doing so isn’t preferred. I want construction to be simple and drilling the glass may not be easy for builders to do or have done. Also, just having screws holding it in without anything else would look a bit unfinished, so a trim strip will fabricated and serve double-duty to keep the glass in-place. Nothing more could happen today after that decision was made since the aluminum has to be ordered.

So the passenger-side seat belt mounts were addressed. Using bolts as on the driver-side wouldn’t work here because the seat sits lower and there’s no wrench access to the backside of the cross tube. Threaded inserts will be made so the bolts will screw straight into them – more material to order.

The inboard shoulder belt mount presented another challenge, that a drill can’t be maneuvered into position, other than a small pilot hole. The roll hoop diagonal blocks access from both above and below, so it’s going to take a bit of digging, probably with a die grinder.

The last picture deserves a bit of explanation. In order to drill out the bushing holes to 0.625″, smaller drills were used to get a start, and a Unibit created the rear-side holes no problem. Unfortunately, the diagonal in the forward passenger footwell meant that the handheld drill couldn’t be run in from that side, so a drill bit was used from the rear to reach through to the forward surface. As you may know, a 0.625″ drill bit is pretty big, and in that confined space, I had to sit right over the top of it… right over the top of the drill. So when the drill grabbed, even though it was expected, it still presented me with a strong wake-up call – thump! – to the “boys.” Yes, much colorful language ensued…

And lastly, it’s fascinating where all you web visitors are coming from – I had no idea. 31 countries and counting! In fact, there’s one red dot showing up south of Ghana or Ivory Coast, in the ocean. Perhaps it’s a cruise ship because Google Earth shows no islands in that area, unless it’s a bit inaccurate and it’s actually Sao Tome. Very interesting!

19 Jan 2012

Some time back I ran across an applet that shows where visitors to a site come from. Just for fun it’s been added to the title page and in just one day, I’m blown away by how far flung car people are. It’s very sobering to realize that people all over the world are waiting for me to (hurry up already and) finish the car. I hear you! If the applet doesn’t appear, try refreshing your screen in case your PC caches webpage contents. (Also, you can click on the map and get more info about which countries people are in. For some reason that function works fine on my work PC but causes my home PC to crash Internet Explorer. Oh well.)

In other news, I was talking with one of our composite experts at work who mentioned that he’s having a composite class… and he strongly recommended I attend. And yes, he does visit this site… wonder if he’s telling me something…

15 Jan 2012

On a whim, the windscreen and frame was dealt with and since it hadn’t been thought through, there was a lot of sitting around and staring at it before work started. On the one hand, it would look nicely finished with black silicone between the glass and frame. On the other hand, any car that sees track use – like this one – should have its windscreen easily removable, making things a bit more challenging.

What was done ahead of time was to locating a custom glass place that caters to hot rods, and this windscreen should be a piece of cake since it’s flat. A friend expressed concern early-on that a flat windscreen is asking for trouble since wind pressure can easily bend it. That’s one big advantage of curved windshields, that the curve acts like a dome, making it far stronger to wind pressure. A flat windscreen has no way to politely direct the force to the edges, so it bends. However this shouldn’t be an issue since this windscreen is less than 12″ tall and will be supported around the entire perimeter. If there is any bending seen, a subtle support down the center can be added later.

One thing learned on Kimini was that over time, a hot windshield will soften and cold-flow even fully-cured silicon. For that reason this windscreen will have positive supports so it can’t slowly creep down like a glacier. Because the glass vendor can put holes anywhere in the glass, screws will be used as the hard mounts, suitably insulated from the glass by plastic bushings.

Another issue that’s been dealt with is avoiding a windscreen with corners of less than 90 deg, like the windscreen on a Caterham. I saw a new 260 hp model (around $60K I believe) and one bottom corner of the glass that “wraps around” the cowl had already snapped off. For this reason there’ll be an aluminum filler panel along the bottom of my windscreen, so the windscreen ends being a simple rectangle. Pictures when there’s something worthy.

Oh, and the fiberglass air inlet came out “okay” enough to use. Being of moldless-construction, it was assumed that it would need a layer of Bondo to smooth out the imperfections, and so it will.

8 Jan 2012

Decided to make the air filter cover from fiberglass and used the moldless construction technique, where a foam core is shaped and the glass applied straight onto it. Summed up, the quality of a composite panel is directly proportional to the amount of labor and care used in preparation and lay-up. As always, vacuum-bagging would have made a huge difference, except that even if a pump was available, the foam’s so delicate it would’ve collapsed with 15 psi on it.

My possible mistake was wrapping the core in plastic to make it easier to separate from the hardened epoxy. That left an annoyingly flexible layer that kept moving around as the three layers of glass were applied, so the jury’s out. The wrinkles shown aren’t a big deal since they’re on the inside, and the part will be painted. The concern is that the loose plastic changed the radii of the curves enough to make it fail on the “good enough” scale, and we’ll know that tomorrow, which is also a back-to-work week. I should add that the last picture is of the part setting-up on a scrap piece of aluminum – it wasn’t layed-up directly onto the engine cover.

7 Jan 2012

Had a good work day and completed the right-hand gills. Building one of something is great fun, building a few, less so, and building six, well, not so much. But they’re done so on to other things. The round object at the back-center of the nose is a big hunk of brass. Brass, being fairly heavy, is very handy for keeping things in place during fabrication, but I discovered that it has another feature, that it’s really awesome at absorbing heat. This was discovered after using it to weigh down a tube I was welding, and long after the metal tube cooled, I went to move the brass – big mistake. Yeah, it was still really hot…

Someone recently asked why I hadn’t made a hammer-form for the gills. The answer is that because each gill is unique, it would take six hammer-forms, which would very likely take more time to fabricate than just doing them the way I did. Also, because metal is springy, a hammer-form really only serves as a template for how the finished object should end up (such as a fender.) Actually using it to form the metal over will – without a couple trial pieces – result in a part that needs to be bent more that the form permits if it’s the actual shape.

Another couple panels are needed on each side of the nose to block off the big openings on either side. As it is, the nose lets incoming air bypass the radiator. Either metal panels or composite can be used, but since the panels are so simple, it’s not worth making a mess over, meaning composite.

The cover over the air filter is needed and I have mixed feeling about how to fabricate it. As mentioned above, a hammer form could be used, but as said, it’ll get me close, but not to the extent that I can just hammer a sheet of aluminum over it and be done. Unlike the nose, this might be a place to use composite due to the compound curves. I’ll have to check to see how much carbon/fiberglass is on-hand. Since I’m not into the clear-coated carbon “thing”, it doesn’t make much sense to use carbon other than for bragging rights. Meh, maybe if I’m in a good mood I’ll use composite on the nose, too.

4 Jan 2012

This holiday has been the least productive ever. It wasn’t from lack of trying, just a lot of stuff coming up. I even took off this week as a “real” vacation, but got dragged into some day-job related stuff – defending the free world and what not. Then there was replacing two toilets, made infinitely more fun with <em>seven</em> trips to the hardware store. Then there was chasing off raccoons in the middle of the night, several times.

Anyway… some work really did get done. As mentioned before, the front grill is done, and the left-side “gills.” I like them and purposely left them slightly imperfect. Not sure whether to add stiffening beads – it’s unclear if air flow will start them vibrating. Then there’s possibly adding wire mesh on the outlets, but that can be done later.  The pictures pretty much show how they’re fabricated. They’re sitting in-place – loose – so don’t look lined up, but they’re okay. They look good, big and aggressive, and have rounded ends that go with the rest of the car. I’m happy, in spite of all the whining. Just have to do the other side now…