History: Mass dampers: forgotten ingenuity

By: Bas Naafs

The 2005 and 2006 Formula One seasons  saw Fernando Alonso take the world championship in his Renault R25 and R26. Characterized by reliability and traction, vulnerable at top speeds. This balance made sure that both seasons were exciting and interesting until the very end. In 2005, Alonso was challenged by Kimi Raikkonen in his McLaren MP4-20 which had better speed, but less reliability. Even though Kimi won more races, it was Alonso that took home every point he drove for. In 2006, with new tyre rules, we saw the comeback of Michael Schumacher and Ferrari. Again, a terrific season unfolded. People often forget that the 2006 season saw the introduction of the V8 engine. That took less of a dramatic change than the current V6 turbo’s did in 2014. In general, two cylinders were cut off from the V10, a new seven-speed transmission was introduced to accommodate the loss of power and off they went. The new V8 gave Renault an advantage. The R25’s V10 lacked power. With the new V8’s this gap was bridged, and including the excellent aerodynamics which the R25 already had, the R26 became an absolute beast. McLaren couldn’t follow, and was not able to attack in 2006. The ‘single set of tyres per race’ rule was abolished and Bridgestone finally managed to bridge the gap to Michelin, that proved to have mastered the former rule quite excellent in 2005. Happy campers as they were, Bridgestone was back in the game with Schumacher homing in on his eighth world title. Renault rose to the challenge, and used some pretty canny ideas to maintain their title in 2006.

Quality, not quantity

Other than Renault’s success in this period shows us, the team was still tied to a budget. Even though there’s no factual information about budgets used by teams, it is believed that Renault had the fifth highest budget, almost half of what Ferrari and McLaren used. Fair enough, Renault has always been the master of turning their slim financial resources into successes on the track. They were able to do this by what some believed to be finding the holy grail in motorsport: optimal correlation between CFD results in the wind tunnel and performance on track. One of the biggest challenges in Formula One is to find perfect correlation between wind tunnel and race track. This is not a given thing, it is highly sought after and not so often found. Remember Ferrari’s wind tunnel problems during Alonso’s career for the Scuderia? They had virtually no correlation between all the efforts put in the wind tunnel and Grand Prix results. So they decided to build a new one after they already moved to Toyota’s tunnel, which didn’t work either. It showed us how important correlation is. 100% correlation therefor doesn’t exist, but some teams can get close. Renault was one of them. They managed to put working aerodynamic components on their car, improving their performance with every update made. Apart from these aerodynamic gains, Renault needed that little bit extra to stay ahead of money guzzling teams like Ferrari and McLaren. Rob Marshall, an engineer working for Renault, came up with that little bit extra during the 2005 season. An idea that was brilliantly simple, yet difficult to master. It was already being used in ship building, architecture and aviation. It was a system that made sure that vertical and horizontal movement could be accommodated, making sure that nothing collapses, breaks or shakes. But not just for the benefit of structures, also for the benefit of Formula One cars as were are now going to see.

Frequency and amplitude

The mass damper is not the kind of device  you would normally see in a Formula One car. Particularly because of its weight. The mass damper in the Renault R26 weighed over 10 kg. Not exactly what you call weight saving. Also, the mass damper was fitted in the R26’s nose, which is quite high above the ground and far away from the car’s centre of gravity. So, one must understand that the mass damper had quite the effect to be able to overcome its downsides. What does it do? Simply put, the mass damper was a nine kg round plate put in a cylinder. The plate was centered by two springs that gave the plate vertical movement. The cylinder was part of the chassis and formed a rigid part of the car. Even more, Renault claimed the car was built around the damper. The damper was made to counter vertical movement by the car. In other words, it had to make sure the car ran smooth around the track. A Formula One car shakes and vibrates when it jumps over kerbstones and little bumps on the track surface. The damper counters this by making the same movement in the opposite direction. Normally the tires of a Formula One car vibrate at a frequency between eight and twelve hertz. This vibration creates two effects: changing weight loads between the track and the surface of the tires, and a disrupted airflow underneath the car; airflow vital for the diffuser to work. The damper makes sure that this vertical oscillation (movement of an unsprung mass around a single point, i.e. the bouncing Formula One car) is countered. Let’s take a non-factual example to explain the effect. Let’s say the four wheels of a  race car put a total amount of 500 kg of pressure on the tarmac. This amount continuously fluctuates while the car drives round the track. This fluctuation results in any amount of pressure  between 400 and 600 kg. Adding the mass damper, any vertical oscillation gets the same amount of counter movement, cutting the oscillation in half. This results in the car putting a more consistent amount of pressure on the track, favouring grip and traction through corners. It had a substantial effect for the Renault R26. The car didn’t need to be adjusted for more downforce to be able to corner faster, which was beneficial for fuel consumption and top speed.

Yet still, forbidden

Did it work? Yes it did, and quite well actually. Renault was as dominant in the first half of 2006 as they were in 2005, but a storm was brewing as the FIA started to question the working of the mass damper. It was in fact a loophole in the rulebook, because the mass damper clearly gave an advantage that was both measurable in mechanical performance as in aerodynamic performance. But all aerodynamic components were to be immovable. Was the mass damper immovable? Yes and no. The cylinder was fixed, but the plate wasn’t. The system wasn’t exactly a huge secret either and most teams were already running with their own versions, but as add-ons, which weren’t as big a part of the chassis as  Renault’s system was. Rob Marshall moved to Red Bull in the winter of 2005/2006 and took with him his ideas for the mass damper. The FIA started to worry about the possible size of the mass damper. Some teams were thinking about much bigger weights that could also move diagonal. The FIA had to do something about it, unfortunately it was Renault that had to suffer the most. The week before the Grand Prix of Germany, the mass damper case was opened and in august it was considered illegal. It was a movable object that gave an aerodynamic advantage. Simple as that. Renault wasn’t happy, as they believed the banning of the system would cost them three tenths of a second. This was true, because after the ban on mass dampers, Renault lost quite a bit of speed. Ferrari came alongside and dominated the second half of the season taking five wins. However, Alonso was able to keep up and delivered at the moments he needed to, taking home one win and a couple of podium places after the German Grand Prix. Just enough to crown himself champion of 2006.