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Thread: FSAE Lincoln 2013

  1. #51
    Originally posted by Jack028:
    Congrats to all of the teams at FSAE Lincoln.

    Huge congrats to the University of North Texas as well. They are a first year team who managed to compete every event including endurance and placed 31st overall. Unfortunately they did not hand out a rookie of the year award this year.
    Originally posted by whiltebeitel:
    Thanks, mdavis!

    Kaley, I appreciate all your hard work to keep eveyone informed! Someone's got to feed the ravenous alumni!

    I'll second the mention of UNT. They came to the Texas SAE Student night and gsoaked up all the advice they could get. They did a great job! Husker Motorsports also did very well in their 2nd year.

    Looks like A&M's black flag in endurance was due to a faulty stator.

    Thank you for mentioning us. We are very proud of our 31st place finish, our University didn't have an FSAE program this time last year. We had just started the process and were able to compete in all of the events.

    We'll see you next year!

    -Mike
    UNT - Mean Green Racing
    University of North Texas - FSAE '12-'13 [1st year for UNT], '13-'14

  2. #52
    Originally posted by Z:
    Much as I like the overall concept of Cal-Berkeley's car, there are nevertheless many details that can be improved.

    The chassis, for one, is poor. Frankly, it is typical of all the FSAE spaceframes I have seen in that it is far too complicated, has terrible load paths, and consequently has more weight and less stiffness than it could/should have. I figure it has about twice as many tubes as are necessary, and probably three times as many nodes (all of which take time to cut and weld).
    I was wondering if you could be a little more specific about what it is that you find to be poor design in Cal-Berkeley's spaceframe (or any other team's chassis for that matter), particularly in regards to the load paths and excess tubes. There's a nice picture of their chassis in the link on page two.
    Fitz Matush
    Auto Seat Tester

  3. #53
    Ok, fun times were had, but I have two gripes, well, three.

    1. The faster cars in the autocross should run first in the endurance. If they're going to make any attempt to "normalize" scores, then the faster autocross cars should drive on a clean track and the slower cars should get a track that has already been rubbered in. The way it works now, The slower cars are slow, and the faster cars are doubly (no not doubly, but you get my point) faster because there's more rubber on the track.

    2. The cost report is a complete sham. This convoluted process of costing is a joke. Aside from flat-out lying on your cost report, the costs involved are absurd. Here's another idea, provide a MSRP for everything. If you don't have the MSRP, say, for a sponsored part, then a copy of whatever value your sponsor is claiming for their tax deduction. This way, the parts and their associated costs are all searchable and verifiable. Additionally, it removes the "sweetheart deals" that some teams are using.

    3. Where were the recruiters? Maybe they hung out at UW the whole time, but in Fontana they were aggressive and numerous. This competition isn't about building a race car, and it isn't about a learning process. This competition is really about getting jobs. Specifically, getting jobs in the motorsport industry. I was really disappointed in the lack of recruiters I saw this year.

    4. (I lied about there being 3 gripes, sue me.) If we finished 24th in the enduro, and there were 27 teams that finished overall, I feel that we shouldn't have gotten 30th. Yeah, I know why, with points etc, but there are three teams that didn't finish the race that beat us? How does that logic work? There should be either a penalty for not finishing, or a bonus for completion, but the last time I checked, you can't win if you don't cross the finish line, business presentations/cost reports/etc be damned.

    Anyway, enough bitching, I have to finish my flow calcs for next year's undertray...

  4. #54
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    Originally posted by BluSTi:
    Ok, fun times were had, but I have two gripes, well, three.

    1. The faster cars in the autocross should run first in the endurance. If they're going to make any attempt to "normalize" scores, then the faster autocross cars should drive on a clean track and the slower cars should get a track that has already been rubbered in. The way it works now, The slower cars are slow, and the faster cars are doubly (no not doubly, but you get my point) faster because there's more rubber on the track.

    2. The cost report is a complete sham. This convoluted process of costing is a joke. Aside from flat-out lying on your cost report, the costs involved are absurd. Here's another idea, provide a MSRP for everything. If you don't have the MSRP, say, for a sponsored part, then a copy of whatever value your sponsor is claiming for their tax deduction. This way, the parts and their associated costs are all searchable and verifiable. Additionally, it removes the "sweetheart deals" that some teams are using.

    3. Where were the recruiters? Maybe they hung out at UW the whole time, but in Fontana they were aggressive and numerous. This competition isn't about building a race car, and it isn't about a learning process. This competition is really about getting jobs. Specifically, getting jobs in the motorsport industry. I was really disappointed in the lack of recruiters I saw this year.

    4. (I lied about there being 3 gripes, sue me.) If we finished 24th in the enduro, and there were 27 teams that finished overall, I feel that we shouldn't have gotten 30th. Yeah, I know why, with points etc, but there are three teams that didn't finish the race that beat us? How does that logic work? There should be either a penalty for not finishing, or a bonus for completion, but the last time I checked, you can't win if you don't cross the finish line, business presentations/cost reports/etc be damned.

    Anyway, enough bitching, I have to finish my flow calcs for next year's undertray...
    Some of these things are going to sound brutal and cold hearted. No personal offense intended, but you've now seen the level of competition at these events. It's gone up a ton in the 3 years worth of competitions that I've been around.

    1. You could call the rubbered in track a perk of doing well in autocross. If you want that advantage, drive faster in that event. But this is a risk/reward type of thing. Weather, a blown engine oiling the track (both examples from MIS), etc. are a really easy way for the top autocross teams to get screwed during endurance.

    2. You guys did decent in the actual cost portion. It looks like it was report quality and a penalty that cost you a lot of points in the event. Those are things you control. The event is pretty clearly defined, you choose the level at which you compete.

    4. Total points are total points. The way you score those points are again defined in the rules. You choose the level at which you compete, and how you feel about it afterwards. The penalty for not finishing is 0 points, and the reward for finishing is points. It's that simple. The efficiency score can add in a lot of points if you don't finish, which throws a nice wrench into things (we gained 44 points in Michigan without finishing endurance, which we weren't expecting) but it is part of the game we're choosing to play as competitors.
    Matt Davis
    University of Cincinnati
    Bearcat Motorsports: 2012-2013: Suspension guy

    Bilstein: 2013 - ??: Product Engineer

    This post is a collection of my own thoughts and opinions, and in no way, shape or form reflects the thoughts/opinions of my company, my university or anyone else but myself.

  5. #55
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    Originally posted by slicktop:
    <BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Z:
    Much as I like the overall concept of Cal-Berkeley's car, there are nevertheless many details that can be improved.

    The chassis, for one, is poor. Frankly, it is typical of all the FSAE spaceframes I have seen in that it is far too complicated, has terrible load paths, and consequently has more weight and less stiffness than it could/should have. I figure it has about twice as many tubes as are necessary, and probably three times as many nodes (all of which take time to cut and weld).
    I was wondering if you could be a little more specific about what it is that you find to be poor design in Cal-Berkeley's spaceframe (or any other team's chassis for that matter), particularly in regards to the load paths and excess tubes. There's a nice picture of their chassis in the link on page two. </div></BLOCKQUOTE>
    Slicktop,

    Firstly, my comments about there being "twice/three times" as many tubes/nodes as necessary was a bit of hyperbole. But there is a lot of complication there that is unnecessary, and the load paths are not good. Secondly, this is a very big subject, best explained with lots of pictures (and by your teachers! ), but I will try to give what constructive comments/criticism I can here.
    ~~~o0o~~~

    STRUCTURAL REQUIREMENTS OF CAR CHASSIS - In general (and "big picture") terms, the "worst case" loading condition has the car supported on a pair of diagonally opposite wheels, with all the other parts of the car, such as driver, engine, fuel tank, bodywork, and the other two wheels, hanging of the "diagonal bridge" that spans between the two opposite corners. The vertical loads from all these parts includes gravity, aero, and any inertial loads resulting from vertical acceleration (the car may have left the ground over a hump, and now lands heavily on high ground under its diagonally opposite corners). There are also many little details about how to feed loads locally into the chassis, but no space to cover those here.

    The above loading condition includes a large "torsional" component about the car centreline. Building a car that is strong enough to survive the above loads also means that it should be stiff enough for easily tuned handling (via LLTD, etc.). FSAE cars are small and light (and slow) enough that they can get away without too much strength or torsional stiffness, but for a given weight more strength and stiffness will never hurt them.

    The obvious overall chassis shape to carry the above "major load paths" is an "X" shape in plan-view, with a wheel at each corner of the X. The X's two diagonals are thus two intersecting beams that carry the major loads, and in side-view they should look roughly like "bridges" (ie. roughly like a wide "A", or arch bridge). A typical V-engined Formula car is not far from this shape. It has a strong box-shaped fuel-tank at the centre of the X, the driver sits between the two forward facing arms of the X (which form the cockpit sides), and the two cylinder heads and sump-plate of the stressed engine form the rearward facing arms of the X.

    Here is (hopefully) some ascii-art of the Gordon Murray designed McLaren F1 three-seat "supercar" of the 1990s.

    .....^front^.....
    FL<--d-->FR
    ..p.X..d..X.p..
    ...p.X.d.X.p...
    ...p.XOX.p...
    ...s.X.e.X.s...
    ..s.X..e..X.s..
    RL<--g-->RR

    (With, FL = front-left-wheel, etc., , p = passenger, d = driver, O = fuel tank, s = storage space, e = engine, g = gearbox.)

    The Xs represent the main arms of the (carbonfibre) chassis, with these "crossing over" around the central, and very strong, fuel tank "O". The two front arms conveniently form deep armrests either side of the driver's bucket seat. This car is an excellent example of packaging a great deal (three people + 6L V-12...) into a very compact overall package. Well worth studying...
    ~~~o0o~~~

    Getting back to FSAE, these cars are obviously even smaller than the quite compact McLaren F1. Roughly speaking, the engine is where the fuel tank "O" is in the above sketch, and the rear-wheels are either side of this. Building a strong and stiff (ie. fully triangulated) "torque box" around the engine, and using the mandatory side-impact tubes as in the above sketch, is a good way to get high torsional stiffness (look up "encastre" beams vs beams with cross-sections that are free to deform). And a whole lot of other things.....
    ~~~o0o~~~

    Getting back to the Cal-Berkeley chassis. Some criticisms (IMO)...

    1. The loads from the rear-wheels, which should be following paths generally towards the diagonally opposite wheels, instead head almost straight upward to the spring-damper mounted at driver's head height! Then the loads have to come back down to the chassis side rails via the long and narrow triangles either side of the engine. A much more direct route, with the heavy S-D and its rocker mounted much lower, would be better.

    2. Still at the rear of car in side-view, either side of the engine are four diagonal tubes. the bottom two form the abovementioned narrow triangle, and the top one is the mandatory main-roll-hoop bracing. Why the second-from-top tube??? I guess it is to strengthen the S-D mount, but it is not really necessary.

    3. The side-impact tubes, either side of driver, have a big bend (in plan-view) right in the middle of them! These are under compression or tension, so better if straight. Is this for elbow room? It seems there is some removable bracing from the bend forward to the front-hoop. Is this in case of possible scrutineering issues? Anyway, straight sides to the cockpit, or better bracing would be better. I reckon the various templates (plus maybe an inch or so) guarantee enough elbow room, foot room, etc.

    4. The upper-wishbone-front-arms feed their loads into tubes that essentially put them in bending (ie. sideways). Not really too big a problem given the low loads in FSAE. But these loads then go forward to the front-bulkhead before heading back to the rest of the car. A more direct path would be better. Ie., continue the upper side-impact tube all the way to the front-bulkhead (which is also better for crash strength).

    5. There is a lot of diagonal bracing of the floor under the driver's feet, but then there are large sections of the the floor left unbraced (ie. under driver's seat, although it looks like there is some sort of bolt-on seat bracketry++?). Given the floor needs some sort of panelling anyway, it is probably easiest to simply skin the whole floor with a sheet of steel, spot-welded to the lowest chassis rails. 1 mm thick would be truck-tough and weigh a total of ~4 kg. Production car bodies are closer to ~0.5 mm (~0.020") thick, more than strong enough, and would weigh ~2 kg (then subtract any CF/ally panels, bracing tubes, etc...). This steel floor forms the lower tension member of the diagonal bridge you have to build, and greatly increase strength, stiffness, safety, etc.

    Bottom line is that I reckon the mandatory tubing required by the rules is almost enough for the whole chassis. So, front-bulkead for IA, front-roll-hoop, main-roll-hoop, various tubes required to connect these three bulkheads in side-view, the triangulated bracing required aft of the main-roll-hoop, and then a sheet steel floor. A removable engine-differential "bracket" (= "partially stressed drivetrain") triangulates the engine bay, and torsionally stiffens everything up.

    Finally, and importantly, take the suspension mounting points to where they suit the chassis (ie. to the nodes of above tubework), not the other way around. Remember, it is the whole package that has to work well, and "suspension kinematics" is a relatively small concern.

    Z

    (PS. I like Cincinnati's spring-damper actuation! Could you please post some pics, Mdavis? (I tried, but it all got too hard...))

  6. #56
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    Originally posted by BluSTi:
    Ok, fun times were had, but I have two gripes, well, three.

    1. The faster cars in the autocross should run first in the endurance. If they're going to make any attempt to "normalize" scores, then the faster autocross cars should drive on a clean track and the slower cars should get a track that has already been rubbered in. The way it works now, The slower cars are slow, and the faster cars are doubly (no not doubly, but you get my point) faster because there's more rubber on the track.

    2. The cost report is a complete sham. This convoluted process of costing is a joke. Aside from flat-out lying on your cost report, the costs involved are absurd. Here's another idea, provide a MSRP for everything. If you don't have the MSRP, say, for a sponsored part, then a copy of whatever value your sponsor is claiming for their tax deduction. This way, the parts and their associated costs are all searchable and verifiable. Additionally, it removes the "sweetheart deals" that some teams are using.

    3. Where were the recruiters? Maybe they hung out at UW the whole time, but in Fontana they were aggressive and numerous. This competition isn't about building a race car, and it isn't about a learning process. This competition is really about getting jobs. Specifically, getting jobs in the motorsport industry. I was really disappointed in the lack of recruiters I saw this year.

    4. (I lied about there being 3 gripes, sue me.) If we finished 24th in the enduro, and there were 27 teams that finished overall, I feel that we shouldn't have gotten 30th. Yeah, I know why, with points etc, but there are three teams that didn't finish the race that beat us? How does that logic work? There should be either a penalty for not finishing, or a bonus for completion, but the last time I checked, you can't win if you don't cross the finish line, business presentations/cost reports/etc be damned.

    Anyway, enough bitching, I have to finish my flow calcs for next year's undertray...
    1. The slow cars aren't slow due to the amount of OPR on track.

    2. Statics are your friends. You don't need rare driver talent, a big budget, and lots of manpower to be a top contender in them. Learn the game, play along, and profit. My team has had its best season ever capped by a seventh place finish at Lincoln with a strong focus on performance in static events.

    3. While it's true that I didn't get to talk to the ladies of Space-X and Raj Nair at Lincoln like I did at MIS, it's not fair to say that there weren't networking opportunities to be snagged.

    4. I'm with mdavis. The current endurance scoring does a great job rewarding a finish and penalizing a DNF.
    -----------------------------------
    Matt Birt
    Engine Calibration and Performance Engineer, Enovation Controls
    Former Powertrain Lead, Kettering University CSC/FSAE team
    1st place Fuel Efficiency 2013 FSAE, FSAE West, Formula North
    1st place overall 2014 Clean Snowmobile Challenge

  7. #57
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    Originally posted by Z:


    2. Still at the rear of car in side-view, either side of the engine are four diagonal tubes. the bottom two form the abovementioned narrow triangle, and the top one is the mandatory main-roll-hoop bracing. Why the second-from-top tube??? I guess it is to strengthen the S-D mount, but it is not really necessary.

    Z

    (PS. I like Cincinnati's spring-damper actuation! Could you please post some pics, Mdavis? (I tried, but it all got too hard...))
    Z,

    I would imagine that the 2nd from top tube is to help support the shoulder harness bar, since it is mounted quite close to the main hoop (rules require that the bar must be kept from rotating or something like that, we've never run a harness bar that way, so I don't know the exact wording).

    As for our spring/damper actuation, I'm also a big fan of it. It reduced frame build time pretty significantly by reducing the number of frame jig points by 4 and removing a couple of pain in the a$$ tubes to cut/fishmouth (the ones between bellcranks on our previous pullrod setups).

    Here are some links to pictures:
    front:
    https://fbcdn-sphotos-a-a.akam...661_1928147013_n.jpg
    https://fbcdn-sphotos-c-a.akam...087_1969609803_n.jpg
    me in tilt, also front damper:
    https://fbcdn-sphotos-g-a.akam...2550_704556415_n.jpg

    rear:
    https://fbcdn-sphotos-e-a.akam...171_1819233678_n.jpg
    https://sphotos-a.xx.fbcdn.net...126_1851982330_n.jpg

    If you guys want to see more pictures, there are a bunch of them on our facebook page at: https://www.facebook.com/bearcatmotorsports

    We know our frame has a ton of extra structure in it, especially in the front end. That was our fault for submitting the impact attenuator report before finalizing our suspension and frame design. There's probably 5lbs that can come out of the nose of the car, let alone all the extra stuff elsewhere.

    -Matt
    Matt Davis
    University of Cincinnati
    Bearcat Motorsports: 2012-2013: Suspension guy

    Bilstein: 2013 - ??: Product Engineer

    This post is a collection of my own thoughts and opinions, and in no way, shape or form reflects the thoughts/opinions of my company, my university or anyone else but myself.

  8. #58
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    Originally posted by BluSTi:


    3. Where were the recruiters? Maybe they hung out at UW the whole time, but in Fontana they were aggressive and numerous. This competition isn't about building a race car, and it isn't about a learning process. This competition is really about getting jobs. Specifically, getting jobs in the motorsport industry. I was really disappointed in the lack of recruiters I saw this year.
    I can't say for sure since I wasn't there... but nope sorry, it's about the learning process. Besides, that's actually more fun than working in the motorsports industry.
    "Man, I need to practice more!" - Kenny Wallace
    "Try not to have a good time... this is supposed to be educational." - Charles M Schulz
    -OptimumG 2005-2006
    -Turner Motorsports 2008-2009
    -Black Swan Racing 2010 & 2011 Team and Driver's Champions
    -HPD Race Engineer 2011-2014
    -Currently Freelance Data/Race Engineer

  9. #59
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    Originally posted by mdavis:
    As for our spring/damper actuation, I'm also a big fan of it. It reduced frame build time pretty significantly by reducing the number of frame jig points by 4 and removing a couple of pain in the a$$ tubes to cut/fishmouth (the ones between bellcranks on our previous pullrod setups).

    Here are some links to pictures:
    front:
    https://fbcdn-sphotos-a-a.akam...661_1928147013_n.jpg
    https://fbcdn-sphotos-c-a.akam...087_1969609803_n.jpg
    me in tilt, also front damper:
    https://fbcdn-sphotos-g-a.akam...2550_704556415_n.jpg

    rear:
    https://fbcdn-sphotos-e-a.akam...171_1819233678_n.jpg
    https://sphotos-a.xx.fbcdn.net...126_1851982330_n.jpg

    If you guys want to see more pictures, there are a bunch of them on our facebook page at: https://www.facebook.com/bearcatmotorsports
    ...
    -Matt
    Matt, Thanks for pictures!
    ~~~o0o~~~

    To the True-Believers of Rockers-and-Push/Pull-Rods,

    Did thunderbolts rain down upon Cincinnati because of their heathenism?

    Would they have gone faster if they were more righteous??

    Is 9th place overall so bad???

    (Have I drunk too much coffee today????? Err, that last one is a "Yes"! )

    Z

  10. #60
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    Originally posted by Z:

    Matt, Thanks for pictures!
    ~~~o0o~~~

    To the True-Believers of Rockers-and-Push/Pull-Rods,

    Did thunderbolts rain down upon Cincinnati because of their heathenism?

    Would they have gone faster if they were more righteous??

    Is 9th place overall so bad???

    (Have I drunk too much coffee today????? Err, that last one is a "Yes"! )

    Z
    Z,

    There's still a lot more pace in the car, even without aero. More efficiency too, as we found out in Lincoln. And there's plenty of extra weight in the car that can be removed next year (hopefully). From my talks with the guys that will be continuing on the team for the next couple of years, they plan to continue the direct acting setup for a couple of years, so it will be interesting to see how the concept progresses, especially with less weight.

    I even included a picture of our ultra-not secret balance tuning devices (aka spring rubbers) for you, Z. I figured you'd like that, with your talk of elastomeric springs/dampers F500 style.

    -Matt
    Matt Davis
    University of Cincinnati
    Bearcat Motorsports: 2012-2013: Suspension guy

    Bilstein: 2013 - ??: Product Engineer

    This post is a collection of my own thoughts and opinions, and in no way, shape or form reflects the thoughts/opinions of my company, my university or anyone else but myself.

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