The Bontaz industrial group, a leading automotive supplier based in Haute-Savoie, supports the French Ice Sports Federation (FFSG) via a French bobsleigh partnership by providing financial, technological and human support to French bobsleigh.
Bontaz’s R&D team works closely with technical staff and bobsleigh team to improve equipment and optimise performance during training... With the goal of reaching the 2022 Olympic Winter Games!
Since 2020, Bontaz’s Development Team Leader, Sébastien Chatel, has benn supervising the project - design, analysis and validation of tests in real conditions - and has chosen Hottinger Bruel & Kjaer’s to supply the strain gauges used. Here he answers some questions!
The partnership with the French Ice Sports Federation (FFSG), which focuses on bobsleigh, was set up in 2015, at the initiative of our founder Yves Bontaz. It is a global partnership, covering financial, technical, material, media and human issues.
The skills sponsorship targeted a continuous improvement process for the bobsleigh by R&D engineers in order to optimise technical performance. For BONTAZ, whose DNA is technological innovation, this was a great opportunity to apply our industrial know-how while helping to give new impetus to French bobsleigh.
This strong commitment has resulted in:
Initially, the aim was to supply a BONTAZ-made bobsled for the chassis, as this was a purely mechanical matter - a subject in which the BONTAZ project team has great expertise. Only the fibreglass hull was purchased. A lot of work went into dismantling an existing bob to scan all the parts and reproduce them in 3D using design software. The Official French Teams also gave advice or ideas for improvements on different parts so that they could be integrated into the first 'prototype'. Once the assembly of the Bobsleigh was finalised on the computer and checked to ensure that everything could be fitted together without collision, the manufacture of the parts began. Once the assembly was completed, the pilot wanted to test the bobsled on the track and give his first impressions of the bobsled he was using in competition. Several passes were made in order to improve the behaviour of the bobsleigh(s), as it was possible to interchange some of the independent elements of the welded part. Tests were carried out on each part of the bob, such as the pads with a dedicated trolley, the design of the brake to make it more ergonomic and the tensioners that allow the rider to obtain better steering sensations.
HBK had already worked with the FFS (French Ski Federation) on the start gate handles to find the best technique to propel oneself ahead of everyone else at the beginning of the race, thus increasing the chances of success at the finish. With the bobsleigh, the logic is the same because the push corresponds to 1/3 of the final performance (tin addition to the piloting and the bobsleigh) and the complexity wich has to be addresses is that it is necessary to coordinate 4 pushers simultaneously with successive boarding phases. Moreover, there are 3 different types of handles and each one has its specificity: the pilot handle which allows to follow the flexion created by the lever arm, the side handles where we play on the torsion of the axis attached to the hull and finally the 2 back handles where we come to observe a compression of the material. Strain gauges are ideal for all these measurements. The installation of the gauges was easy because all the handle systems were designed to be removable and therefore easily deliverable, unlike the bobsleigh wich measures around 3m80. Once the gauges were in position on the bobsleigh, calibration using a dynamometer was carried out in the BONTAZ premises, with the support of Astrym as all the measurements were recorded by the data acquisition system developed by this company. This operation is one of the most important if reliable and exploitable results are to be obtained. Using the Catman software, the French Teams could graphically represent the efforts experienced by each handle and correlate them with a video in order to improve the athletes' technique.
In addition to the bobsleigh instrumentation, BONTAZ supplied "wheel" kits for use during summer training on La Plagne athletics track; the equipment was matched as close as possible to those used in actual competition. For example, the handles are the same as the ones on the bobsled that does the World Cup runs, as well as the height in relation to the track, so that they can easily transpose the technique between the different seasons. Previously they used a weighted cart which they could not sit in and had handles in the form of simple tubes. Now all four athletes can board, so each of the push steps can be worked on and improved. During the preparation courses, the bobsledders made several descents recorded via the central acquisition system and filmed while modifying the pushing techniques (horizontal or with an angle, hands clenched or spread out). In the evening, the whole thing was analysed by the staff to see what worked and what didn’t, in order to avoid slowing down the bobsleigh during this phase of the race.
The bobsledders had to rethink their training methods due to the new equipment and become rigorous in retrieving and exploiting the results, as they did not previously have access to that much data on their individual and collective performances. This allowed us to determine the typical crew and in which positions people perform best. From a chronometric point of view, we are talking about a gain of several 0.01 seconds or even 0.1 seconds on thrust alone; this will also have an influence on the maximum speed during the race, so there are still 0.1 seconds to be gained.
It is true this kind of adventure is not common in our daily work. Usually we trial the parts we develop ourselves because we have an in-house test laboratory, but in this particular case, the best judge of is the track, the rider's sensations, the times and we can go from one extreme to the other very quickly in the event of injury or lack of confidence on the part of one of the EDF members. They are men and women who train hard all year round for one minute of racing at more than 130 km/h, we worked hand in hand behind the scenes with a lot of sweat and sacrifice. Despite this pressure, the exchanges were always very friendly, constructive and focused on the common goal of a medal at the Olympic Games. Suggestions for improvements came naturally, discussed by SMS or video directly with the pilot, Romain Heinrich, who has been the leader of this EDF Bobsleigh team for several years. The feedback from various tests was very comprehensive in order to validate the direction we were taking and see the study to the end. During all these years, BONTAZ was able to provide them with the necessary means to have access to things they had never known before, due to financial restrictions. I still remember the wind tunnel tests in Geneva for this F1 on ice where you could see the excitement on their faces and all the video clips that made it possible to get a close-up view of this great sport, which usually receives little media coverage.