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Thread: 2015 Formula Student Germany

  1. #31
    Quote Originally Posted by Z View Post
    Also, big congratulations to GFR (aka "The Team of Many Names")!

    For those of you who still doubt that a 50 hp single can do well in these competitions, consider that second placed Stuttgart was 43 points behind GFR, and third placed Graz was 183 points back! Both these Teams have very high horsepower cars (Graz = 90+ hp from their website, not sure about Stuttgart).

    Oh..., but just checked GFR's website, and ... they actually claim 51 hp!
    ~o0o~

    Julian,

    35 point penalty??? That, and better tyres for the Wet-Pad might have made the difference?

    Z
    Yes, WetPad and the penalty made the difference.
    If you saw the Delft car on the WetPad, it's insane. Like there is no water. I guess every half-decent team would win with those tires. Impressive what they managed to design!

    The penalties got a lot of teams this year. There is an online-tool for ESF. I actually don't know how it exactly works but they told me, you get like dozens of mails of failed documents (it's not one document but for every(!) electrical part of the car, LV and HV) and they missed deadlines.
    It's no excuse whatsoever (just make yourself an Excel list when which part has to be re-uploaded...) but as the list shows, it got a lot of teams. Actually Delft had the same 35points penalty but it got removed, I don't know why...

    But at least you can be proud of the Zurich team for their Acceleration time. 3,300 ; 3,352 ; 3,303 ; 3,300 -> That's quite good


    Harry, there were a couple of DQs in re-scrutineering: KIT Combustion had a restrictor that was too big, Munich was too loud in noise (probably would have been third overall), Zwickau got DQ as well (something electrical).

    As far as I know, there were no scrapping DQs in Endurance (although Rennteam Stuttgart "denounced" GFR on a Facebook post that they would be scrapping a lot, not very sportsmanlike...).

    The DQs in AutoX killed the event. Yes, I know it's within the rules. But it made watching AutoX really bad. You did never know if you can cheer for a good time because half of them got DQ'd.
    The guys on the track listened veeeery carefully at some cars and did not care about others (talked with another guy).
    Additionally you cannot challenge a ruling. Who has proof? Who decides?
    And the worst part: Some drivers got told after the first run that they got a DQ and could decide if they go out and change the car or do another run. And some guys got not told! That's outrageous!
    I think we need another rule there. It's very very frustrating.
    Hopefully they do something about it...
    -------------------------------------------
    Alumnus
    AMZ Racing
    ETH Zürich

    2010-2011: Suspension
    2012: Aerodynamics
    2013: Technical Lead

    2014: FSA Engineering Design Judge

  2. #32
    Quote Originally Posted by JulianH View Post
    Yes, WetPad and the penalty made the difference.
    If you saw the Delft car on the WetPad, it's insane. Like there is no water. I guess every half-decent team would win with those tires. Impressive what they managed to design!

    The penalties got a lot of teams this year. There is an online-tool for ESF. I actually don't know how it exactly works but they told me, you get like dozens of mails of failed documents (it's not one document but for every(!) electrical part of the car, LV and HV) and they missed deadlines.
    It's no excuse whatsoever (just make yourself an Excel list when which part has to be re-uploaded...) but as the list shows, it got a lot of teams. Actually Delft had the same 35points penalty but it got removed, I don't know why...

    ...
    They succesfully appealed, they did al the documents on time so a penalty would be wierd.
    Tristan
    Delft '09 Team member, '10 - Chief Electronics
    'now' (Hardware) Security Engineer

  3. #33
    Julian, it made watching the AutoX really frustrating indeed; that's why I am for the "old" ground clearance rule, it was really easy to check, albeit (as already mentioned) depending on the setup, you could definitely scrape...

    I am aware of those DQ's, but I believe these were not marked as DNF's, might be wrong though!

  4. #34
    The intent of the ground clearance rule is spelled out in the comment in T6.2, namely it is intended to minimize ground effects with sliding skirts and to minimize track damage to pristine surfaces like Ford's Romeo VDF where we ran the Michigan FSAE for 3 years. Picking out cars that are intent on circumventing the ground effects part is relatively easy as it ties in with the design. But calling the scrapping was, and apparently still is, problematical.

    The current rule relies on a transient condition and is based on call-ins from the corner workers/marshals which can be very subjective (some might even say "biased".). Do you call-in a front wing end plate or a side pod touching the track briefly or not? Or do you look for it scrapping for 1 or 2 seconds? JT's comment that the "1 inch static ground clearance" rule will not prevent all scrapping, but it did cut it down a great deal on the subjectivity. With the old (current) rule, we scrutineers either got an earful from a certain member of the SAE staff about being too tough on teams (we were not being "customer friendly"), or we were criticized by some teams for not being tough enough! We could not win! That criticism went away with the "1 inch static" rule.

    Michael Royce,
    FSAE Rules Committee 1995-2009,
    Chairman 2000-9.
    And other "stuff".

  5. #35
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    Or you could just have no rule about ground clearance or touching. If somebody wants to drag their wings or chassis on the ground, they'll punish themselves enough by messing up their car and when they choke off their underbody flow. I understand why the rule exists when we were at Michigan and the track was freshly repaved before the first NASCAR race there in 2011, but after that the Cup guys are more then willing to drag anything on the ground before or after crashing. At Hockenheim all the open wheel series are touching the ground constantly and besides that all the bumpy sections are in the parking lot section of the courses. Lincoln Air Park definitely doesn't care. I don't know enough about the other events to talk about them. I know it will never happen, but it seems like a rule that could be gotten rid of entirely.

    But if a rule has to exist, the 1" ground height clearance is the lesser of evils I think. Whenever a human/multiple humans have a chance to make a judgement call they will screw up at least occasionally if not more often.
    Last edited by theTTshark; 08-03-2015 at 01:16 PM. Reason: Words are hard
    Trent Strunk
    University of Kansas
    Jayhawk Motorsports
    2010-2014

    Now in NASCAR land. Boogity.
    Opinions Are My Own

  6. #36
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    Quote Originally Posted by JulianH View Post
    But at least you can be proud of the Zurich team for their Acceleration time. 3,300 ... -> That's quite good
    Julian,

    Yes, it is impressive.

    Now, where did I see exactly that time of 3.300 seconds for Acceleration before? And why do I have a feeling that Combustion Teams could also do such times ... at least if the students spent more time talking to their friendly Toothless Hillbillies at the local dragstrip? Hmmm....???

    Well, for next year's RWD-C-car students, I have found some guidelines on how to match, or even beat, Zurich in Acceleration - ACCELERATION - INTO THE LOW 3s, and more discussion on Acceleration Launch V-T Graph. Also, here are some thoughts on "Why More R%" not only gives you faster Acceleration times, but also greatly improves your performance in AutoX and Enduro (and more discussion throughout those threads).

    Julian, out of curiosity, would it be possible for you to post a Velocity-Time graph of ETH/AMZ's recent 3.300 second Acceleration runs, so we can compare it with the above V-T graph I drew last year?
    ~o0o~

    Small pedantic point (because I had to look it up).

    Scrap - n. 1. small piece of something larger, a fragment. ... ~vb. scrapping ... 6. to discard as useless. [C14: from Old Norse "skrap"; see SCRAPE]
    ...
    Scrape - vb. 1. to move a rough or sharp object across a surface, esp. to smooth or clean. ... ~n. 11. the act of scraping...


    So ... I think that the current Rules require the cars to be DQ'd for "scraping", after which the Team might think about "scrapping" them.

    Z

    (PS. Fully in agreement with TTshark. In fact, put more bumps on the track, and let the well-suspended cars separate themselves from the bad-suspension cars (which either have low ground clearance and get ripped to pieces, or must be set-up with high-clearance/hi-CG and are thus slower...).)
    Last edited by Z; 08-04-2015 at 12:38 AM.

  7. #37
    Since you are talking about V/T; For those interested, the speed at FSG Acceleration was measured over the last 5 meters.
    Tristan
    Delft '09 Team member, '10 - Chief Electronics
    'now' (Hardware) Security Engineer

  8. #38
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    The FSG-TV-Livestream site was the only one where I could find speeds at the end of the Acceleration runs. Assuming those were reasonably accurate, here are some comments on the performances.

    Car#..Team.............Speed...E.Time
    ==========================
    E33...ETH-Zurich..112......3.30 - 1st - because fastest (smallest) time.
    E13...Munchen.......103......3.56 - 2nd - must have had very good launch because only needed slowish top speed.
    E15...Delft..............122......3.58 - 3rd - clearly a poor launch because had highest final speed (of all cars), but slower ET than Munchen.
    ...
    C15...Graz..............106......3.90 - 1st C-car - similar top speed to above, but clearly TOO MUCH WHEELSPIN at startline!
    ...
    C9....Esslingen.......112.......4.21 - ~Mid-field - same top speed as Zurich, but must have spent FOREVER at the startline!!!

    Conclusions.
    ===========
    1. The V-T graph I drew a year ago has very similar top speed (top-edge of graph) and ET (right-edge of graph) to Zurich's numbers above, and since "area inside the graph" is also the same (ie. = 75 metres), it follows that Zurich's "rate of acceleration" throughout the run (ie. the slope of left-edge of graph) must also be very similar. So things like the tyre-road-grip, max-power-expended, etc., are also remarkably similar.

    2. To match or beat Zurich's Acceleration times the RWD Combustion-cars need MORE R%!!! Fortunately, this will also make them faster in AutoX and Enduro.

    Z

  9. #39
    Quote Originally Posted by Z View Post
    1. The V-T graph I drew a year ago has very similar top speed (top-edge of graph) and ET (right-edge of graph) to Zurich's numbers above, and since "area inside the graph" is also the same (ie. = 75 metres), it follows that Zurich's "rate of acceleration" throughout the run (ie. the slope of left-edge of graph) must also be very similar. So things like the tyre-road-grip, max-power-expended, etc., are also remarkably similar.
    Z
    We've had discussions about this when you first posted the graph you mentioned. I still think you're off on some of the most important numbers, and I think that an identical end time of 3.3s does not necessarily imply 'remarkably similar' rates of acceleration throughout the run. There's many different speed curves that will lead to identical finishing times over 75m. By saying that your particular curve must be pretty close, you're implying that your assumption of 2.5g off the line is also right (a key assumption in your thesis of how to get to sub 3.0s acceleration runs for RWD cars). And it's not. I'm not saying it's not possible in principle (although I also doubt that), I'm saying that's very likely not how Zurich did it.
    It's much more likely they started at below 1.5g, and, thanks to downforce, hit about 1,75g just as they hit their power limit at around 17 or 18m/s.

    I think you're also not taking into account that cars are allowed to start 0.3m before the start line. This makes a massive difference (the car crosses the start line already going almost 3m/s). I'm pretty sure it took Zurich about 3.49 seconds to cover the actual first 75 meters (so from where the car was staged to 74.7m into the measured run). That's another reason why I'm pretty sure those two speed graphs will look quite a bit more different than you seem to think.

    Thijs
    Last edited by Thijs; 08-06-2015 at 10:40 AM. Reason: spelling
    Alumnus
    Formula Student Team Delft

    2007 - 2008: Powertrain, Suspension
    2009: Technical Lead
    2010 - present: Grumpy Old Fart/Concerned Citizen

  10. #40
    So, like the runs already suggested: You need a really good launch control to get sub 3.5 as most cars are first traction and then power limited (up till their max speed, assuming they reached it and for all electrics this is the same).
    Tristan
    Delft '09 Team member, '10 - Chief Electronics
    'now' (Hardware) Security Engineer

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