Formula 1 Aerodynamics and the impact of aerodynamic testing restrictions applied to development
While recent change in Formula One engine regulations have shifted focus on engine power, fixed engine design restrictions, aerodynamics remains a crucial area in improving car performance. However, in line with reducing development costs, constraints on the usage of aerodynamic testing (track testing, CFD and wind tunnel testing) have also been curbed.
Aerodynamic resource restrictions in Formula One were introduced in 2009 as a means to limit a team’s expenditure on aerodynamics. To prevent the kind of ‘arms race’ seen during engine development in the early 200’s, running full-size wind tunnels was curtailed along with CFD usage.
The restrictions were introduced by the Formula One Teams Association FOTA, with
teams asked to submit a declaration at the end of each testing period summarising the resources used. This was measured by the number of Wind Tunnel wind-on hours per week. This is the length of time the Wind Tunnel is switched on with the speed above a nominal value. The longer the WT is running for, the more parts that can be tested, or the more data points that can be sampled for each part.
The measurements were averaged over eight-week periods, which allowed teams to cope with periods of high demand, as long as they operated at a reduced capacity later on in the eight-week cycle.
For 2014, the testing restrictions became an appendix to the sporting regulations - thus enforceable by the FIA. The new rules saw a reduction in the WT and CFD limits to 30 hours and 30 teraflops. The number of WT runs was limited to 80 and occupancy time is restricted to 60 hours (the length of time a model can be installed in the Wind Tunnel, having parts changed or ready to be tested)
Franck Sanchez , Aerodynamics Project Leader Scuderia Toro Rosso, UK) has had to adapt quickly to these big overhauls aero management..
“With the introduction of both new engine and bodywork stringent regulations, the decision to switch back from a V8 engine to a V6 turbo engine was not so much a matter of performance than a question of image”, says Sanchez. “Increasing F1 popularity by making it greener and making its power units more similar to road cars has been a massivechallenge for engine manufacturers and the impact on both aerodynamics and car design has been significant."
The challenge faced by F1 teams was exemplified by Ferrari in 2014, who reportedly sacrificed engine performance in an effort to chase aero efficiency.
"In short: it was made to pass the idea that all the woes of the F14T are the fault of the power unit," Former Ferrari engine chief Luca Marmorini was quoted as saying by Italian journalist Leo Turrini.
“Undoubtedly, aerodynamics remains a key factor in Formula 1 car performance” adds Christian Taucher (CFD Engineer Sauber Motorsport AG, Switzerland). “Recent change in engine regulations increases the role of engine power. However due to the fixed engine design per season the main development area to improve the car performance remains on aerodynamics”.
As far as CFD and wind tunnel testing restrictions are concerned, Sanchez and Taucher preview recently changed in terms of approach to design.
“CFD and wind tunnel testing restrictions have been further strengthened in 2015 with even smaller testing resources allowed” says Sanchez.
With fewer parts being tested in the Wind Tunnel, the development rate is likely to drop. One way to counteract the reduction in the number of parts tested would be to test each part for longer, sampling more detailed data. However, occupancy limits will limit this, as it works out to be only 45 minutes per run, which must include the time taken to change parts on the model.
Unlike large works outfits such as Mercedes AMG Petronas, mid-field teams such as Toro Rosso and Sauber AG are compelled to restrict their spending to areas where they expect to see performance returns. Despite running the same under-powered Renault power-unit, the Faenza squad also appears to be doing a stronger job than their more moneyed sister-outfit Red Bull Racing.
With strong performances from both Toro Rosso and Sauber at the opening Formula One Championship round in Melbourne, it looks like this prudent approach is starting to reap benefits, as Taucher explains:
“As the usage of both is limited, the strength of both testing methods need to be fully utilized to find the best performance gains, spending time and runs in both CFD or wind tunnel needs to be carefully planned to follow the most promising concepts and ideas as the resources have become much more restricted than in recent years” he says.
reduction in WT testing could lead to a greater emphasis on the use of CFD in the development process. Designing parts in CFD prior to tunnel testing allows all but the most promising directions to be filtered out without wasting tunnel runs and time. During its first two F1 seasons the Marussia team garnered a lot of publicity thanks to their CFD-only (no wind tunnel testing) strategy.
Aerodynamic Development of the Škoda Fabia R5 Rally Car – Aspects, Challenges & Lessons learned.
The International Conference of Advanced Automotive Aerodynamics won’t just be confined to Formula One. With acceleration and traction loss in rallying being a more byzantine practice than circuit racing, the influence of aerodynamics is just as crucial to tarmac and gravel rallying as it is in open-wheeler racing.
Škoda has over 100 years long tradition in motorsport and has been continuously active in rally since the early 60´s. Experts from the Škoda R&D Center, including aerodynamicists, regularly participate in the development of our motorsport projects.
Michal Sumec (Aerodynamicist Škoda Auto, Czech Republic) will report the aerodynamic development of the Škoda Fabia R5 Rally Car and its benefits to the series projects development. The R5 class applies to 1600cc turbocharged petrol 4WD series production cars. With the FIA imposing a ‘price cap’ on all major parts (or example, a complete turbocharger will cost 1000 euros, a front subframe 2500 euros and an R5 bodyshell complete with homologated safety cage for a very reasonable 18,500 euros), there has been an increase emphasis on aerodynamic efficiency.
“In order to support a market launch of the new generation of Fabia, the Rally version (in R5 FIA-Class) was developed at the same time during the development of the series car” says Sumec.
“Special aspects of a typical use of a rally car to the aerodynamics (road: tarmac / gravel / snow or ice, average speed ranging from 60 kph to 120 kph, temperature range from -20°C to +50°C, altitude ranging from 0m to 2500m asl) will be mentioned”.
Sumec will also details Skoda’s project goals, tasks and disciplines, as well as aerodynamic efficiency, drag, down-force and approaches to cooling in various competition environments. Innovations and responses to constraints and limitations (through FIA regulations and homologation requirements) will also be discussed.
“Process and results of the aerodynamic development will be presented in comparison with the predecessor (Fabia S2000 rally car)” explains Sumec. They will include “some innovative approaches (development activities based only on experience and CFD simulations, plus one wind-tunnel session for validation purposes at the final phase of the project)”.
Sumec will also describe the new methods and tools (e.g. automatic optimization) that were tested, proved and are now available as regular applicable for the series projects development. Ancilliary benefits of the project; such as motivation of the team, deeper working relationships (particularly in the styling department) will also be talked about.
Thermal and Aerodynamic Development for New NSX-New Honda FIT/JAZZ/Accord
Unlike rallying and circuit racing, aerodynamicists for road-going sports cars face a unique set of challenges. Balancing performance on the open road, in traffic must all be considered whilst maintaining a harmonious and striking aesthetic that attracts a sports car enthusiast.
Yasuyuki Onishi (Assistant Chief Engineer Honda R&D Co., Ltd, Japan) will be on hand to discuss the challenges that aerodynamicists face in the design of a sports car.
Christian Taucher, CFD Engineer Sauber Motorsport AG, Switzerland