Duke University Motorsports is a student group that designs and builds open wheel, single seat race cars to compete in the Formula SAE competition sponsored by the Society of Automotive Engineers. The team consists of Duke students from both Pratt and Trinity, in all classes. The purpose of the team is to provide students with a way to gain practical design and manufacturing experience in a fun and challenging setting.

Sunday, March 25, 2012

Parking Lot Test Round 2

Last time, we did not have much time to really test the car. It started raining soon after we got to the parking lot. So, today, we went for the round two.
Firstly, we made some adjustments in the suspension and collected data for different suspension settings.

Then, we made changes in the braking ratio and more adjustments in the suspension. The data collected in our practice will be used to make small changes in the fuel map.

Saturday, March 24, 2012

Active Aero Progress

I wrote the first iteration of the active aero software yesterday and debugged it today.  Right now, all the functions are implemented minus the gearspeed functions.  The controller right now takes the accelerations, filters them, and sends a value to the motor controller based on a 16x16 lookup table.  It also outputs that value to an external DAC so that we can see wing position with data acquisition, and it's also really useful for debugging.

 Right now the motion is jerky because the motor is running on 6V, the potentiometer is only loosely attached, and the motor control PID isn't tuned yet.  But the arduino code works, so that's a step forward.

Wednesday, March 21, 2012

Testing in the Circuit Parking Lot

Last night we did some testing in the parking lot in circuit to test that the drive train was fixed properly as well as a general shakedown of the car. Here are a couple of videos of the car driving:

Fixing the Drivetrain

So we had a few problems with the drivetrain at NCCAR, which were fixed over the week.  The combination of the relatively large half-shaft angle, improperly sized half-shafts (too short), and tripod housing that were not deep enough caused the drivetrain to fail.
To fix this, we made new (deeper) tripod housings, JP made a new half shaft, and we re-aligned the drivetrain (properly this time).

Friday, March 16, 2012

Aero controller electronics

I got the PCBs for the aero controller in the other day (also from Laen's PCB order), and soldered them up.  So far, so good.  The accelerometer was the part I was most worried about since it is a LFCSP package with no visible leads (and thus no real way to inspect and rework), but I tested the board and all three axes of the accelerometer work great.  The DAC works too, so the last step is just interfacing the Arduino and Jrk motor controller.
Aero controller board, all soldered up

Sunday, March 11, 2012

Spring break and NCCAR update

We headed out to the North Carolina Center for Automotive Research on Thursday and Friday to do an initial shakedown and track testing.  After a long and tiring spring break, we got the car to the point of being ready to drive just in time for our planned NCCAR test date.

Car with aero!  The rear wing is the old one from last year.
I would like to give a huge thanks to Simon and Sam at NCCAR for allowing us to use their facilities at a highly discounted rate.  NCCAR has amazing facilities, and we hope that they'll continue to support our program in the future!

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...

Saturday, March 10, 2012

Making the seat, part 2

The new seat weighs only 2.9lb.

putting down the ribbing using spray adhesive and foam

seat layup

popping the seat out of the mold

Thursday, March 8, 2012

heading out the NCCAR

We're heading up to the NC Center for Automotive Research in a few minutes.  Me and JP were in the garage til almost 5 last night, so I will post more information some time later when I've had more than 2 hours of sleep.

Sorry about the lack of updates this week - this week has been really busy trying to get everything ready for today.  But I think it's all ready now!

Friday, March 2, 2012


So turns out that last start was just "lucky", as Brian at PE put it.  Apparently the PE3 can't deal with a 12-1 trigger wheel and the stock 3 tooth cam trigger, so we swapped the trigger wheel back to the stock wheel (12-0) yesterday.  A little bit tricky, since the clutch cover wouldn't actually come out of the frame, but it was a relatively smooth process all things considered.

After swapping in the stock wheel, we changed the ECU settings to reflect the proper trigger wheel, and it fired up right away.  Timing looked good, and the engine ran, idled, and revved just fine.

A little more work needs to be done on the intake to strengthen it; it was flexing a lot more than we were comfortable with.