Tech (aero) details at 2021 Ypres Rally

The debut of Ypres Rally in the World Rally Championship gives us a new opportunity to take a look over some technical (aero) details related to brake and engine cooling, average speed and aero reliability issues.

 

K.Rovanperä/J.Halttunen, Toyota Yaris WRC, Ypres Rally 2021, 3rd

Ypres high stage temperatures, with values close to 30ºC, were a concern for the teams. Brake temperatures were constantly monitored in order to ensure adequate cooling and ensure brakes’s reliability. For this purpose, Toyota uses adhesive temperature strips (THERMAX©).  These strips are designed for surface temperature monitoring and are located both in the disk and in the caliper, with different temperature ranges at each location, as shown in the image below.

The highest temperature reached is marked in each label with a colour change and, as the colour change is irreversible, the strips always indicate the highest temperature attained. In the images above, temperatures of 140ºC and 180ºC were reached in the caliper, and around 218ºC in the brake disk.

K.Rovanperä/J.Halttunen, Toyota Yaris WRC, Ypres Rally 2021, 3rd

Radiator cooling is always an issue at these temperatures. In order to prevent leaves and dirt accumulation in front of the radiators, the teams use different designs of grilles. In Ypres, Toyota introduced a new design, consisting of a vertical grille with an open space (basket) in the center. The goal would be to allow all leaves and dirt to accumulate at the bottom of the basket, thus allowing air to free flow over the basket, and ensuring adequate cooling.

G.Greensmith/C.Patterson, Ford Fiesta WRC, Ypres Rally 2021, 47th (SR)

MSport introduced an improved version of the front grille protection already seen in previous events. A new level of protection was added on top of the existing grille, probably designed to avoid the accumulation of leaves and dirt over the original protection.

K.Rovanperä/J.Halttunen, Toyota Yaris WRC, Ypres Rally 2021, 3rd

The Belgian event included some very fast tarmac stages. The average speed of the Hyundai i20 Coupé WRC of Thierry Neuville and Martijn Wydaeghe of 124,2 km/h at SS4 Zonnebeke 1 is the fastest speed set by one of the 2017 WRC cars in a tarmac stage of the World Rally Championship. The previous top speed was set by the Toyota Yaris WRC of Ott Tänak and Martin Järveoja at SS9 Römerstraße 1 in Rally Deutschland 2019, at 123,7 km/h.

 

 

At such high speeds, aerodynamics become critical to get the maximum outcome from the cars. The image above shows how all the aero kit allows the car to remain stuck to the ground on a fast corner, thanks to the downforce generated. The result is a very fast pass through this type of corners, as shown in the video above.

T.Neuville/M.Wydaeghe, Hyundai i20 Coupé WRC, Ypres Rally 2021, 1st

Even though the high speeds, there were very few reliability issues affecting aero parts. During Sunday stages Neuville/Wydaeghe lost their winglet on top of the right front fender, as shown in the image above, showing also Tänak/Järveoja intact winglet (below). The result was probably a small loss of front right grip in the fastest portions of the remaining stages.

C.Breen/P.Nagle, Hyundai i20 Coupé WRC, Ypres Rally 2021, 2nd

Also, Breen/Nagle damaged the lower dive plane on the right side of the car during the Sunday morning stages. The consequence was also losing grip on all the right side of the car, due to the impact of dive planes on the downforce generation.

E.Evans/S.Martin, Toyota Yaris WRC, Ypres Rally 2021, 4th

Some dust over the tarmac of some stages allowed to visualize the wake of the cars, as it is usual in gravel events.

J.Huttunen/M.Lukka, Hyundai i20 Rally2, Ypres Rally 2021, 1st WRC2

The new Hyundai i20 Rally2 made a successful debut in competition in Ypres, driven by Jari Huttunen and Mikko Lukka, in what will probably be the first of a successful career. One of its main characteristics is the developed aero design, which we already reviewed here.

T.Neuville/M.Wydaeghe, Hyundai i20 Coupé WRC, Ypres Rally 2021, 1st

 

9 thoughts on “Tech (aero) details at 2021 Ypres Rally

    • 2021-08-18 at 07:57
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      Muchas gracias!! Un abrazo!!

      Reply
  • 2021-08-18 at 02:33
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    Thank you again for your always very relevant analyzes. It is a pleasure to read you ! Passionate about aerodynamics and rallies, I read you each time with passion.

    Reply
    • 2021-08-18 at 07:59
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      I see that we share the same passions, which is great. And glad that you enjoy it, thanks for your kind words!!!

      Reply
  • 2021-08-18 at 05:11
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    I’m rather curious how much Toyota struggled compared to Hyundai here, given how advanced simulations and test programmes are these days. Actually, it brings me to mind a rather unrelated sport but with similar problems: Kawasaki in WSBK. Recently, the bumpy tarmac seems to disturb it more than its competitors, suggesting their inherent chassis stiffness goes too far the other way to cope with sudden loss and regain of grip. Do you think Toyota’s also plagued by this, given there’s very little scope to change the monocoque these past few years? A compromise they’ve built into the car to make it faster at other rallies? I’m assuming this because I think the downforce numbers between the top two teams are already quite similar (Ford obviously is missing some peak prowess there), so this attribute shouldn’t be the game changer.

    Reply
    • 2021-08-18 at 08:06
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      Thank you Kevin for your always interesting comment. I agree with you that both teams (Toyota and Hyundai) have reached very similar levels in aero performance, so the differences on this side are minimal. Not sure if it is chassis related or the confidence that the knowledge of the roads gave to Neuville and Breen, but my impression from the side of the roads was that they two both run smoother on the stages, while all the others seemed to struggle a little bit more (Tänak included). Also, Fourmaux seemed to be well adapted, a pity he had to retire so soon.

      Reply
      • 2021-08-20 at 06:00
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        Yeah, their ability to be smooth instead of getting knocked about by the stages was what sparked the thought in my head. Tanak’s not bad until some minor mistakes; perhaps it’s his unfamiliarity with the Hyundai combined with the stages led to his result. That’s why I think it’s something inherent in the car, and not necessarily just driving style-related.

        Reply
  • 2021-08-19 at 09:46
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    Hello, Thierry Neuville’s car had a small aero part (shaped like an airfoil) attached close to the driver’s side window, close to the side mirror. Started wondering, what would be the purpose and why it was only installed on driver’s side ?

    Reply
    • 2021-08-19 at 14:53
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      Hi Laur! I guess you are referring to the TV camera for front/side images. That’s why it is only on Thierry’s side. Also, Breen and Tänak occasionally carry one. It is inserted inside a small wing in order not to penalise those drivers who have it.

      Reply

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