End of Fall Semester

Today marks our first official day of winter break, which we've been looking forward to for many weeks now. We just wanted to post a quick update of what we ended up finishing the semester within the garage, and where we're heading for the next semester.


First, Maurice and I worked on doing more work on the fuel tank. We finished making the filler neck cuts into the fuel tank base, and welded it all up to create nearly all of the fuel tank. We had to make a minor modification to the filler neck angle (i.e., it didn't fit with the frame geometry...oops), but overall, we were all very happy with the final product.

Making the first cut into the fuel tank base

Maurice happy with the final product

Pictures of Intake and Frame

 I was just at the garage unwrapping the last half of the carbon fiber intake, and it turned out great! They're definitely much stiffer than last year's design, and I'm also happy with their weight compared with previous designs. We're going to be putting it all together relatively soon, so we'll be sure to measure the differences in weight.

We also received an update from Chappell with the frame, and it looks great! I've included a before and current picture of the frame+jig, so things are definitely starting to get rolling!

Two halves and the diffuser/restrictor

Pre-Thanksgiving Update

Duke Motorsports has been very busy the past couple of weeks, so this is going to be a quick run down of all the things we've been up to.

We hosted an E-Social on November 9th, which was a great success. We brought the car up to the main engineering quad and purchased a bunch of pizza to share outside on a beautiful afternoon in North Carolina. We had a lot of great conversations with interested students about Duke Motorsports, and made sure to rev it a few times before we left. Thanks to ESG and all those who helped, it was a great success!.

Exhaust Welding Preparation

Thanks Chappell Anderson!

Yesterday we finally got to send out our frame jig, an exciting milestone.  We should have it back in the beginning of January.  In the meantime, we are getting as many parts ready as possible.  

The team wanted to send a big thanks to Chappell Anderson, sitting in the car below, who has been welding the frames for Duke University Motorsports for years.  Thanks Chappell!

Machining and Drivetrain Redesign Braindump

Hi there; I am going to do my best to summarize what I have been working on over the summer and this fall; admittedly, I should have made earlier posts, so this is going to be somewhat of a long braindump:

Phase 1: Summer Planning and Drivetrain Redesign Version 1

Over the summer, I put in significant hours (a) learning Computer Aided Machining and (b) redesigning the drivetrain. I am leading both the Drivetrain and WHUBS teams this year, so I needed to put in some serious hours so that I could hit the ground running this fall.

The Drivetrain (and the accompanying rear portion of the frame/suspension) is the part of the car that is undergoing the most changes this year, mostly because it was the most problematic part of the car last year. The main issues that version 1 of my redesign sought to address were:

1. Last year, we ran too sharp of an angle from the halfshafts to inner tripod housings, so there was significant friction and we actually had the halfshafts pop out of the tripod housings.
2. Last year, we tried to go to a rigid mounting system (no more turnbuckle) for the bearing carriers, but this had unintended consequences when vibrations created a noticeable side-to-side wobble of the drivetrain when we started turning the chain.
3. Last year, the bottom of the left and right bearing carriers were mounted at different locations (so they weren't coaxial, so adjustment (which involved the use of shims) would cause misalignment.
4. There were also some little things within the design (I won't list them all) that I updated/improved to make our CAD model of the drivetrain better.

Update: Mid October

These past few weeks have been very crazy here at the garage. We've been doing a lot of machining, carbon fiber work, and also a good bit of experimenting with wheel speed sensors. However, the big highlight of the past couple of weeks has been our Alumni Driving event. We were fortunate enough to have a weekend that a lot of our alumni could be here to visit, and to make it a little more special for them, we decided to host a driving day for them early one Saturday morning. Overall, it was a fantastic morning, and we all seemed to have a great time. The list of alumni visitors includes Dan Lacher, Joe Goo, Jules Finlay, Will Gardner, Ivan Wang, and John Ingalls. And without further adieu...on to some pictures!

Ladies first...it always applies

Update: Week of Sept. 17

This week has been a pretty eventful one at the Duke Motorsports garage. Last Saturday, we did some carbon fiber work on the new intake manifold, which turned out great. We applied 2 layers of carbon fiber, and will be adding some reinforcement ribbing in between layers to ensure that the manifold will not flex under the vacuum generated by the motor.

Carbon fiber magic

2011-2012 Team

Here is a picture of the whole team from the 2011-2012 season with some alumni, friends, and family included.

Back to the grind!

We just finished our second successful week at the garage with a visit by some of our own alumni, Dave Coccarelli and Mike Spohn of GE Healthcare. They came by to give us a talk about internship and full-time opportunities with General Electric, especially regarding the highly acclaimed Edison program. They definitely had a full crowd of eager underclassmen!

Dave and Mike mesmerizing the new Motorsports members

Chronicle Article!

Another article about Duke Motorsports and our 2012 year has been published! This time by Margot Tuchler from The Chronicle! Thanks Margot!!!

Click here to read the article

New Article!

We'd just like to express our thanks to Brandon Jackson who just posted a new article about Duke Motorsports and our 2012 year on the Pratt Engineering website! Here's to 2013!!

                                                            Click here to read the article

Thanks to everyone for a great year!

We officially finished competition Saturday, and we placed 12th overall, which ties our best finish ever, even against some really stiff competition this year.

I'd like to say thanks to everyone who has contributed this year - all the members of our team who put in all the time and effort to make this year happen, our alumni, our sponsors, and everyone at the university who helped us out.

At competition

We're at competition right now and done with day 1.

It's been a rough ride so far, but we're weathering the storm.  We arrived to find contents in the trailer had shifted, and war wagon had rolled back and put a dent in our car.  The car rolled back, the chainguard hit a stand, and it hit hard enough to bend the chainguard (1/8" steel) and knock the drivetrain out of place.  First thing we did was remove the drivetrain and check it over.  It seems fine, but we'll see once we're allowed to run the engine.

Our bodywork also got hit.  The nose cone got hit pretty hard, and was cracked along the front.  We worked yesterday to patch the inside and fill the outside, so we'll have to repaint it today.  We'll see how that works out.

We've almost passed tech - the tech inspectors are making us replace a tube and add another one, because they think that our rear wing loads require a 1"x0.049" tube for some reason.  I don't agree, but I'm not about to argue with the rules committee about that right now.  We've cut out what we need, notched the new tubes, and things should be getting welded back in right now.

Not an easy day, but not too terrible either all things considered.

Bodywork Photos

We went for one of the last runs before competition today. After tuning the car, we did a few endurance and accel runs. Most things are finalized, and we got a chance to check our fuel economy, which happens to be fantastic.

Here are a few pictures from today. Check out the bodywork.

And here's a comparison of the car to the CAD model:

Progress update, end of April

We're getting close to competition now, and things are moving along.  A lot of the work now is in testing and tuning, and after yesterday's trip to NCCAR, I think the suspension is pretty much set for competition.  We're also working hard on getting the bodywork done.  The molds are almost ready for the layup, so hopefully over the next week we should have bodywork finished.

 Video of Paul Harraka driving the FSAE car.  His help was invaluable in getting the suspension tuning set in a very short period of time.

Testing at Goodyear Proving Grounds

We went to Akron, Ohio to visit Goodyear's proving grounds on Saturday.  Goodyear is nice enough to host us (and other FSAE teams) at their proving grounds on a number of weekends every spring, and we chose this past weekend to visit.  Unfortunately, it was cold and raining all day, but we at least got some good engine tuning in.

Here are a few videos from this weekend:

Testing 1

Testing 2

Bowling with the car...

EAC Banquet Pictures

Last Saturday we went to the EAC Banquet. We would like to once again thank the EAC for all of the support they give us year after year. We would also like to share some pictures from the event:

John Glushik with the car and some of the team members 

Dean Tom Katsouleas with the Car

Thanks for the picture John!

Making Bodywork, Part 2

We're a few steps closer to completing our bodywork now.  All the molds are put together, and we're done with the initial sanding of two and a half of the pieces.

Our five mold pieces, slathered with epoxy/talc filler and waiting to be sanded.

Pictures and updates after the jump.

Active aero in action

Unfortunately, my phone sucks at taking video, but this is the best clip we got today of the active aero in action.


 Unfortunately, one of the radiator tabs fatigued and broke today, so we didn't get very much running time.  But I'm pleased to say the engine tune is in a much better place than a couple weeks ago and the car drives well.  It's a bit loose right now, but we'll do some more tuning once we get to Goodyear's proving grounds.

Wing angle vs position - red is full downforce, blue is minimum drag

Above is a plot of wing angle from the GPS plot.  Seems to work pretty well so far, but plenty more tuning to go.  I did realize today from looking at the data that my longitudinal accelerometer axis is reversed - oops.  If you look at the graph above, you can see this clearly (the course is clockwise) - there is less wing angle when braking before the corner and lots of wing angle accelerating out of the corner, the opposite of what should happen.

Thank you Goodyear!

Thank you Goodyear for your continued sponsorship of our FSAE team.  We've received this year's set of tires and are looking forward to visiting the Goodyear proving grounds in Akron, Ohio on the 21st (next Saturday).

Making Bodywork, Part 1

We've starting making the bodywork for this year.  There is foam everywhere in the garage now, and we're less than 1/8 of the way done making the molds.

The first few pieces of the bodywork molds

Because of budget constraints, we're making the bodywork molds ourselves this year on the mill.  They will be milled out of small blocks of foam (due to table travel constraints on our mill) and glued together.
 

It's snowing in Durham, NC

Over the next couple weeks, I'll do a reasonably detailed writeup of the process.  The first steps are to prepare the bodywork molds from the CAD models.

Aero Updates

Aero updates: we now have a really big rear wing.

 

Seriously though, we ran with active aero for the first time today.  Needless to say, there a lot of tuning to do with active aero, but it does work, it moves, and the accelerometers don't seem to be too bothered by the car vibration, which is great news.  Sorry there's no picture or video of the active wing yet, but it does move well and responds to lateral and longitudinal accelerations surprisingly well.

First Aero Test

We had our first test with aero yesterday.  My first words after driving the car with aero: Holy S***!  This thing is fast.  We saw 1.9g in the parking lot.

Aero and Active Aero Progress

Aero and active aero are almost done now.  The actuator is now attached to its link solidly now, and the last step on the active aero part is to tune the PID parameters on the motor controller.  We finished putting together the rear wing yesterday too, and so after a little bit of sanding/trimming, the rear wing will be finished.  The last step will be to put together the mounts, which are all done, but just not assembled.

Rear wing put together

More pictures and process discussion after the jump.

Random Pictures

Someone stole our chairs.  This is now the most comfortable chair in the garage.

Apparently someone thought my car needed more downforce

Someone tell Yoshi that the carbon fiber goes into the vacuum bag, not him

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.

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.

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).

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

Pictures from NCCAR

Thanks to our resident photographer, John Ingalls:
https://picasaweb.google.com/109987874687595369672/NCCARMarch892012

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...

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

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!

Engine/ECU

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.

It's alive!

It idles, but still plenty of work to do.  I'm still not sure about timing, so I'm going to think about that for a bit and see if Brian at PE has any helpful tips. 

Progress Updates

Suspension and steering (the steel versions) manufacturing is now done with the addition of the front push rods and ARBs.

Anti-roll bars, ready to be put into the car

 The next step for suspension is to set the car on the ground (waiting on wheel studs to come in - the order had to be re-placed yesterday, so mid next week maybe?).  We will probably throw on some old upright anyways for SAE Carolinas on Tuesday, so once the car is on the ground I can get an idea of pushrod settings and alignment.

We're getting everything ready to crank the engine tomorrow, so hopefully everything will go smoothly and we can set idle soon.  If we can get cooling and fuel mounted tomorrow during they day, we should be ready to crank by tomorrow night.

What a day...

Yesterday was an... interesting day.  Lots of things went wrong - first, the torch for the welder broke (the threads for the back cap gave out).  Next, the mill broke - it won't boot up any more.  Finally, we found more clearance issues with the drivetrain and had to cut out the rear frame tubes (again) and replace them.

I have no idea what we're going to do about the mill yet, but it's not going to be a cheap or quick fix.  It's not a great time for the mill to break, but it's not the worst time either.  We don't have too many CNC parts left to do, so we can probably ask for a few favors to get back on track.  But the dent it's going to put in our budget really worries me.

Drivetrain update

We had a slight problem before where the drivetrain didn't fit on our frame mounting points.  That issue has now been resolved by milling down one diff cap, and everything fits fine now.  The lower mounting tabs still need to be made and welded in, shims need to be made, and half shafts need to be cut to length.

Before - notice how the right bearing carrier doesn't match the frame mount location

After - all fixed

More suspension updates

I have everything I need to finish putting together the suspension now except for pushrod inserts.  Steering is set, tie rods are set, and I have everything I need to put together the bellcranks.

Setting the steering rack length

Tie rods ready to be welded

Checking the total steering travel.  Turned out to be exactly what I expected from the CAD model.

Fan controller and SMT soldering

I received the PCBs for the fan controller a few days ago, and I soldered them up today.  The purpose of the fan controller is to take the PWM signal from the ECU (open source) and convert that to a PWM signal for the fan.  Since the fan only runs in one direction, there's only one MOSFET needed, and the circuit becomes pretty simple.

Suspension Progress Update

Suspension is getting close to being done.  Me and Bharat reamed and chamfered the bearing carriers and staked in the spherical bearings last night, and me and JP broke in the bearings and attached them to the car today.  Steering is almost done too - I just need to set the rack length, and it'll be good to go.  The steering column are already drilled, welded, and attached.  We have almost everything we need for suspension and steering, and the goal is to have a rolling chassis by the end of the week.

A pile of a-arms

More pictures after the jump.

Making the fuel tank, part 2

So I ran into an issue today when welding the fuel tank, namely the placement of the fuel pickup bung.  It ended up too close to the main box, and I melted the bung trying to weld in the box.  Oops.  We cut it off, and welded a new one on the back of the tank instead, which should be okay - it just necessitates slightly different fuel routing.

Nope, not good enough at welding to weld that yet...

What I ended up doing:

Not pretty, but it works.

What's left?  I need the sight line tubes to be made in the lathe, and then those need to be welded to the filler neck.  The filler neck then needs to be welded to the main box, and bungs for the check valve and return need to be welded in.  Finally, mounting tabs need to be welded on.  All of this should be done before the end of the week.

More random pictures

Other random stuff that we did today:

John, your ECU box is finally in

Muffler endcap.  No, that little hole should not be there.  Will need to plug it with weld.

Figuring out how long the chain needs to be.  Turns out it needs to be 50 links, exactly what CAD predicted.

So the drivetrain for some reason doesn't quite fit the CAD model, and the bearing carrier is offset by about a quarter of an inch.  We need to mill down a diff cap and re-press the drivetrain bearing to make the drivetrain fit where it's supposed to.