|Car with aero! The rear wing is the old one from last year.|
While we were there, of course we found problems, but hey, that's what testing is for. Details on spring break and NCCAR after the break...
Let me just first start off by saying how awesome spring break was. What we were able to accomplish over break really embodies what Duke motorsports is about - a group of hard working, dedicated people willing to do whatever it takes to make this car happen. Of the six of us around for break, everyone gave 100%.
Day 1 (Saturday, the day of the UNC-Duke game): Not too much happened today because of the game. Me and Danny went up to the shop before the game and got the seat mount tabs and pedals machined. Unfortunately, one of the drawings may have been wrong, and two of the holes didn't line up on the pedals, and the machine shop was closed by that point. I would also find out tomorrow that 3 of the 4 seat mount tabs didn't line up with the holes in the seat, so back to the machine shop on Monday...
We also popped the seat out of the mold. Man, that was difficult. Lots of water (to dissolve the PVA), lots of air, lots of force, and lots of razor blades and prying. It did eventually pop out though.
|Seat popped out of the mold|
Day 2 (Sunday): The real work starts today. Costi added another layer of carbon fiber to the intake to reinforce it, we set the front wing mounts in carbon fiber, and I cut the front wing to fit the frame.
|Cutting the big part of the front wing to fit the frame. Cuts nicely using the cut-off wheel.|
We also finished the diffuser mounting. The elevator bolts were epoxied into the diffuser as the hard mounts, and nuts were welded onto the tabs to make it easy to attach and remove. We did hit a small snag in the mounting, where the middle tabs ended up being pretty much inaccessible due to their placement right under the fuel tank, so we welded nuts onto those tabs and took a couple of elevator bolts and ground a groove for the Dzus tool so that it could be screwed in from below. Works great, and everything aligned properly the first try (much to my surprise).
Day 3 (Monday): Danny and JP went to the machine shop to finish the hubs (the clearance for the knurls on the studs had to be machined in), pedals, and seat mount plates. We also received the mill control unit that broke later that day, and so we got the mill working again. Took a bit of fiddling to set the backlash, but we checked everything out and it looked fine. We were able to machine the rear spindles for the press fit into the hub that night as a result.
We were able to get the seat mounted by Monday night for the most part, as well as the headrest tacked into place. However, the welding was not easy because of awkward angles and minimal clearance, so I wasn't able to finish welding on Monday.
Day 4 (Tuesday): I came in early and with a clear head, was able to finish welding the seat mounts and headrest. Me and Matt also laid up the endplates for the front wing so that we could finish the front wing the next day.
|Front wing plates in vacuum bag|
|Sorry for the blurry picture...|
Costi welded up the links for the rear wing mounts (temporary ones for now - the final ones will be carbon fiber), I welded on the tabs for the front and rear wings, and Costi, Danny, and Matt also finished laying up the front wing. We let it set overnight so that it would be ready to go for Thursday.
|A very tired JP working on the drivetrain|
Day 6 (Thursday): We met up bright and early at the garage, got the car into the trailer, and headed off. We arrived at NCCAR at 11ish, unpacked, and got straight to work. I set the alignment and corner weights (which amazingly were perfect and needed no adjustment at all). At this point, the scales said the car weighed in at 432lb with half a tank of gas and no aero. Not bad at all - much lighter than last year (we were closer to 450 with the same configuration last year).
|A view of the garage from the upstairs area|
|The car Thursday afternoon|
Costi swapped in the new fuel pump, and we went out driving again. By this point it was already 4:00, so we only had less than an hour left to drive. I went out first this time, and it felt good, responsive, and cornered well. I did a few full throttle pulls, and it was definitely strong. Launched in first (all wheelspin), short-shifted into second (more wheelspin), and the thing just took off.
Costi got in, started driving, and a little ways in, we hear a snap come from the car. Uh oh. The tripod had backed out of the half-shaft, and popped the retaining ring out. A combination of too much play in the half-shaft, tripod housing that were a bit too short, and a relatively severe half-shaft angle cause the tripod to catch on the housing and rip itself out.
We got the car back to the garage, with a plan to get a new retaining ring and have the car ready to go again for the next day. We ran around all over the place to find retaining rings that would fit, and while we didn't find any exact replacements, we did find rings that would work well (and as we would later find out, too well), since the grooves weren't very precisely machined.
After we got back, JP got to work on the drivetrain, and we all worked to get aero mounted. The front wing (which weighs in at just under 7lb) took a bit of trimming to make fit, but eventually it went into place without much of an issue. It is nice and strong (we put over 150lb on it just to make sure), and fits beautifully.
Day 7 (Friday): It was a bit rainy in the morning, so we waited for the rain to stop before we went out to run. Unfortunately, things didn't go so well, as the drivetrain grenaded again, this time a bit more catastrophically. The same failure happened, with the tripod pushing itself out, only this time, since the retaining ring was stronger, the tripod stayed in and chewed up a pushrod, the tripod housing, and actually put enough force on the a-arm mounts to slightly deform one of the camber block frame mounts. It also bent the bearing carriers. Oops.
At this point, there was no way the car was running again without a major fix, so it was time to pack up and leave. We will fix the drivetrain issue with a better toleranced half-shaft, new (deeper) tripod housings, and we will need to remachine bearing carriers to replace the broken ones. Lessons were learned, but we will get this fixed and the car up and running again very soon.