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.

Tuesday, January 31, 2012

EGT amplifier

As I mentioned before, I wanted to create a cheap, robust, small, and waterproof EGT amplifier for the car this year.  I soldered up the board about a week ago, and it works great.

For more details on the EGT amplifier circuit, click through:

Sunday, January 29, 2012

Mill broken...

Our mill is broken.  The 3 phase converter powering the spindle motor went up in smoke...
The internals of a Phase-A-Matic static phase converter.  Yes, that is cardboard.

The 3 phase converter hooked up to the mill was a static 3 phase converter.  Since a static phase converter only provides two of the three legs while running, the motor can't be run at full power.  This approach was probably the wrong one, but I never noticed it until it broke.  I've decided to go with a VFD for the mill over a rotary phase converter since a) they're actually cheaper right now, b) quieter, no moving parts, etc, and c) even though I doubt we'll use any of the extra functionality, it'll be there just in case.  But mostly a).  We'll see how that goes, but luckily right now mill downtime isn't going to affect our schedule so long as we can get it fixed by the end of the week.

Tuesday, January 24, 2012

Thank you Summit and Kluber!

The team would like to thank both Summit and Kluber for their support this year both in terms of oils and funding. We just got the oil in and it will be a great way to keep our engine smooth.
We would like to specially thank Fred Pate, Kyle Carter and Cathy for making this happen.

Wednesday, January 18, 2012

"im CAD hat's passt!"

Inscribed on the Porsche 918 RSR, this message was inscribed discreetly under the rear wing.  During the development of the vehicle, there was apparently a lot of back and forth between the design crew and the production crew.  When pieces wouldn't fit together, the engineers would respond: "It fits in CAD!"
image shamelessly stolen from Jalopnik
CAD is an amazing tool, and there is no way we could have made the drastic changes that we did this year without it.  But CAD is merely a representation of reality, only as accurate as what your manufacturing/assembly tolerances are, and only as accurate as your models.

I'll detail the issues we've run into so far after the jump.  Luckily, we haven't run into any showstoppers yet, and the areas that I thought would be the main problem areas are looking good so far.

Suspension progress

Suspension is coming along nicely - most of the tabs are welded onto the frame already and 5 of 8 a-arms are welded.  The inserts will be done by today for the rest of them a-arms, and we should have them all welded in less than a week.  From there, we need to ream, chamfer, and stake in bearings, and the suspension should be finished at that point.
The frame as it sits right now
 More pictures after the jump.

Multi-Cutter Saw...

...is awesome.  Not having to go to the machine shop to cut stock saves so much time, and makes reusing scrap stock so much easier.  Thanks AIT!
The big yellow thing - Dewalt DW872

Tuesday, January 17, 2012

Progress Update 1-17-12

This past weekend has been productive.  We're definitely moving at a much quicker pace than last year, which is essential given the design changes for this year.  There were a few "oh crap" moments followed by "phew" moments shortly after (phew!) and everything is going to plan more or less at this point.  Details after the jump...

Resolving an "oh crap" moment

Wednesday, January 11, 2012

Thank you Applied Industrial Technologies!

The team would like to extend a huge thanks to Jim Novak and Applied Industrial Technologies.  We've received our sponsorship package, and I'd just like to reiterate how awesome Jim and AIT have been this year and years past!

Tuesday, January 10, 2012

Frame finished

I've talked to Chapel and our frame is finished!  We'll be picking it up Saturday.

Parts are starting to arrive, we'll be putting in a big order at the beginning of next week, and as soon as we have the frame in, we'll start welding everything to it.  In a couple of weeks we should have something that resembles a car.

Monday, January 9, 2012

Active Aero Controller

I spent some time over break working on the aero controller, and I learned a few things in the process.  What I ended up doing is creating a baseline calibration based on simulation results and basic vehicle dynamics models, and have since designed the electronics needed to create such a control scheme.
Aero controller design, showing the motor controller and arduino board
Aero controller, showing custom PCB and heatsink for motor controller
More details on the process after the jump.

Sunday, January 8, 2012

Electronics Stuff

Some exciting new things with electrics this year: first, we're getting a new ECU (Performance Electronics PE3).  Second, we're doing active aero, and so the controller for that has to be designed.  John (our main electrics guy) and I have been speccing the electrics over break, and we've come up with a number of project we'll be pursuing.
EGT amplifier board, designed in Altium

Exhaust progress

The exhaust is more or less done at this point - all we have to do now is add the weld-in bungs for the EGTs, add the final tertiary section with a lambda bung, paint, and wrap the exhaust.  It's fully welded and leak tested at this point.  Costi did all of the welding before break, and I just finished the final merge collector weld and touched up a couple of leaky spots.
The initial leak test showed only three leaks (two were small, one was fairly large).  All three were sites with high concentrations of impurities - this just shows how important having a clean weld is - bubbles and pockets form too easily when the weld gets contaminated and these are difficult to remove.
Leak testing the exhaust - the four inlets are sealed by the head, and the exhaust is pressurized by continuously blowing air from the hose.  While the exhaust is pressurized, we spray soapy water over all the welds, carefully checking for bubbles which indicate a leak.