• Lotus 72 CFD

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    For those interested in a bit of retrospective CFD, I’ve written an aerodynamic analysis of the 1970 Lotus 72, as a contribution to Mark Hughes’s latest work, F1 Retro 1970.

    We were extremely fortunate here in being able to utilise the CFD resources of Sharc, and in particular the patient and responsive cooperation of Richard Bardwell. Many thanks to all concerned!

    You can read the full text in the published work, but there is an omission in that, to avoid deterring the non-technical reader, I decided not to list there the full details of the CFD configuration.

    For the technically curious, however, I can now put that to rights: We used a k-epsilon turbulence model, and employed a mesh containing approximately 20 million cells, with a boundary layer mesh comprising 3 layers. A y+1 of around 30 was chosen. The vehicle was simulated with rotating wheels on a rolling road at a freestream airspeed of 50m/s. The sidepod radiator and airbox inlets were treated as outlets (if you see what I mean).

    Two ride-height combinations were used: 40mm front/60mm rear, and 60mm front/90mm rear. Runs were conducted for the Straight Ahead case, and with 4 degrees of steering angle. The frontal area used in the lift-coefficient calculations was 1.372msq. For each CFD case, the solver was run for 1000 iterations.

    Source: mccabism

  • Ducati Team concludes Valencia IRTA post-race test

    After six days of track action at the Circuit de la Comunitat Valenciana (three for the MotoGP season finale, three at the post-race test), the Ducati Team finally prepares to head home and begin preparing for the 2014 season.

    The team that leaves Spain has a different makeup than that which arrived at Valencia last week, as Cal Crutchlow joined Andrea Dovizioso as a team rider on … Keep reading

    Via: motorsport.com

  • Parmac Racing complete last testing day

    For the third day of post-season testing, the MotoGP riders and teams were greeted by a sky that was variable but mostly bleak.

    As had been the case for the previous two days, the ‘Ricardo Tormo’ circuit opened at 10:00 a.m., and Andrea Iannone left the pits at approximately 11:00, eventually finishing his day with a total of 69 laps and a best time of 1’31.594, without being … Keep reading

    Via: motorsport.com

  • The legality of Brabham’s 1983 World Championship

    A couple of recent pieces in the motorsport press have raised separate issues over the legality of the Brabham-BMW which won the 1983 World Drivers’ Championship in the hands of Nelson Piquet. Gary Watkins’s Autosport article re-considered the exotic, ex-Luftwaffe fuel brew used by BMW in the latter stages of the season, while Mike Doodson’s Motorsport article elicited the following admission from then-Chief Mechanic Charlie Whiting that, “All I will say is that we always, um, attempted to make the car as light as possible.”

    Indeed, and not just in qualifying it seems, for Gordon Murray rather gave the game away earlier this year with the following comment:

    “Whenever we planned to stop – we could go without on street circuits – we tended to do 60-70 per cent of the race on the first set of tyres because that meant we could run very close to, or under, the minimum limit before adjusting the weight with the amount of fuel we put in,” (Motorsport, May 2013, p86).

    That’s a pretty unambiguous admission that the Brabhams ran under the legal weight limit in many 1983 Grands Prix, and used fuel-weight as ballast. If you go through the races in 1983 you’ll see that Piquet’s Brabham was almost always the last of the leading runners to pit for fuel, and that he sometimes pitted 5-10 laps or so after the Ferraris and Renaults, his championship competitors. At Hockenheim, for example, Prost’s Renault stopped on lap 20, while Piquet stopped on lap 30.

    Why would Brabham want to stop after everyone else? Well, in the era of refuelling, a car on empty tanks and worn tyres was generally faster than a car which was fuelled-up on fresh tyres. Moreover, in 1983 the Ferraris were shod with bias-ply Goodyear tyres, and thereby tended to suffer greater tyre warm-up difficulties than the Michelin-tyred Brabham. Thus, it was in this 5-10 lap window that the Brabham would often make hay.

    At Spa, Tambay’s Ferrari was running ahead of Piquet until stopping on lap 21; Piquet stopped on lap 24, and jumped ahead of the Ferrari, forcing Tambay to re-pass some laps later. Similarly, at the Osterreichring, leader Arnoux’s Ferrari stopped on lap 28, Piquet on lap 31, after which Piquet emerged ahead, forcing Arnoux to re-pass some laps later.

    So why, then, wouldn’t everyone schedule their pit-stops at 3/4 distance? Well, that extra fuel-weight costs lap-time, and it costs you lap-time on each and every lap that you carry the extra weight around on your back. If you started a race with about 20kg of extra fuel, that would cost you about 0.6seconds of lap-time, which over 30 laps would mount up to a very substantial 18 seconds or so.

    However, if your car was 20kg beneath the legal weight limit when drained of fuel, you could start the race at the same weight as your competitors, but with the ability to run 5 laps or so further. You would suffer no disadvantage in the early stages of the race, and you would also be able to jump ahead of your competitors by running longer. Perfect.

    In fact, just about the only time Piquet didn’t run long was in the final race at Kyalami, when he shot off into the distance on a light fuel load, pitting on lap 28 of 77, able to resume without having lost the lead. It’s possible that the Brabham started the race over the legal weight limit, but was running underweight for a significant portion of this stint. Moreover, in the late stages of the race Piquet slowed considerably, sacrificing what appeared to be an easy victory. Contrary to the explanation given on the day, that Piquet was merely trying to ensure the reliability of his car, he might also have been minimising fuel consumption to ensure the car was actually over the legal weight limit at the end of the race!

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  • Smith seventh, Crutchlow falls in final round at Valencia

    The 2013 MotoGP World Championship campaign ended with mixed emotions for the Monster Yamaha Tech 3 Team in Valencia this afternoon, with Bradley Smith racing to a hard fought seventh place in an enthralling season finale.

    There was to be no fairy tale final appearance in the French-based squad though for Cal Crutchlow, who crashed unhurt on the 10th lap while he was in hot pursuit of … Keep reading

    Via: motorsport.com

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