September 8, 2012 - Time to test the wing!
Other than add the wing and splitter, I hadn't touched any other settings on the car since the Summer Camp a month ago. This was to give me a reasonable before/after picture of the effects of the wing. The short version? My first timed session popped out a 1:01.344. My previous best time in the car was 1:03.388. Yes, that's almost exactly two seconds faster. Two seconds! It may also be the lap record for cars with doors, although I need to do some digging around to be sure. It's certainly the fastest Miata time. Now, conditions were pretty much perfect and everyone was going quickly, but that's still a pretty spectacular difference. Not long ago, that would have been the overall record for cars.
I could feel the difference in the balance of the car as well. Where I'd previously had a bit of oversteer down the fast sweeper, I now had a bit of understeer. According to the rally computer, my peak speed was also something like 6-7 kmh faster than I'd seen before. That peak speed occurs as you're balanced on the limit of grip on the fast sweeper, and is limited (in this car) by the amount of lateral acceleration you can produce. So it's a quick and easy way to get a feel for actual grip. On that fast lap, it translates to sustained cornering of 1.1g or so, with a peak of 1.3.
I then proceeded to spend some time experimenting with wing angles. The next two sessions I cranked the wing down to a fairly steep angle. My fastest time dropped to 1:01.5, but the peak speed went up by 1 kmh. The understeer on the straight got stronger, and it actually became a bit more difficult to drive the car as the balance was changing so much based on speed. I continued to play with various angles, but it became apparent that the rising temperatures were affecting everyone's grip level and times gradually went up as the day went on. Still, it wasn't until the very last (hot!) session of the day that my times finally slipped above my previous best. So that's a big, big thumbs up to the wing, even on our fairly slow track - the average speed on my fastest lap was just a hair over 50 mph. It's also obvious that I need to do more to balance the front out. A lower ride height would help there, but I was leaving everything other than wing angle alone in my experiments today. I'm going to put on the stiff track springs and drop the car down a bit to get ready for an upcoming trip to Willow Springs.
As you can see from the picture, I added some labels to the holes so I can easily keep notes. For those who are interested, I tried C4, A1, B2, C1 and A3 today. It wasn't all perfect, though. It feels as if I lost a coil. I'm still letting the car cool down, but based on a quick test of header tube temperatures, it's the same #1 that has failed twice before.
Brandon also had a good day in his bike-engined Locost. After I was faster than him on the first session, he put his fast pants on and turned a 1:00.355. I believe that's the overall lap record for cars on this track, and so close to the elusive one minute mark!
tags: aerodynamics |
THE DIARY