Analysis: Red Bull’s Hot T-Tray in Korea

Image via Formula1.com – There is a heat signature showing on the front of the T-Tray (right)

With the FOM world TV feed now using on-board Infrared (IR) cameras, it’s been interesting to see how the tyres temperature changes around the lap. But in Korea we were treated to a rear facing IR camera on Mark Webber’s car that showed the front of the T-Tray splitter warming up and staying hot around the lap. This image helps to highlight both the cars set up and the construction of the car around the front of the T-Tray. Many fans jumped to the conclusion it’s the plank itself running hot under the car, but it is in fact the titanium skid blocks conducting heat through to the floor mount.

IR cameras have been a feature on F1 cars for over ten years, when I first noticed McLaren openly testing with Thermoteknix cameras. Since then the technology has matured and team may even race with IR cameras installed to monitor tyre temperatures across the tread. Now the cameras are also used to confirm the exhaust path over the sidepods and floor, in order to be sure the exhaust is blowing where it’s expected to be.

The FIA cameras are similar, but the temperature gradient is simplified to a few colours within a narrow temperature band, so as not to give away too many of the team’s secrets. Pointing them at areas other than the tyres shows the unusual temperature signatures around the car, hot areas such as brakes, exhausts and radiators show up in colour on the otherwise grey image.

The front of the T-Tray on Webber’s car, appeared surprising to many fans and theories of KERS batteries and coolers circulated the internet. In fact the hot spot was a metal reinforcement mounted above the T-tray. This component is part of the system to resist the FIA deflection tests for the T-tray. The protruding carbon fibre splitter is relatively flexible, but to meet the FIA application of a 100kg load up under the tip off the T-tray requires stiffeners to be fitted inside the hollow splitter section. On the red Bull this is formed of three parts; firstly the flat plate extending from the bottom of the tub to the front edge of the splitter. This plate is some 20cm to reflect the FIA that can be applied up to 10cm from the cars centreline. Then there is the vertical strut to help support the front edge of the floor and lastly a metal plate across the top of the splitter edge that connects all the parts together. It’s this last plate that can be seen on the IR camera.

BLOG_PLANK-SKIDBLOCK

On its own it would not be hot, so the source of heat is from the titanium skid block under the floor. Beneath the floor is the cars legality plank, this is aided by several circular Ti skid blocks that fit into holes in the plank. Its these skids blocks that scrape the track and teams will tune ride height and suspension setting to ensure they skims the track, but do not unduly wear. Obviously excessive wear would be a legal issue, but they are remarkably resilient to constant light grounding. On the front of the plank there’s a single central skid block which bolts through the reinforcing plate and the top plate. So the tremendous amount of heat it generates passes through the fastener into the other components. This conducted heat is what’s seen on the IR camera.

31 thoughts on “Analysis: Red Bull’s Hot T-Tray in Korea

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  4. Dear Scarbs,

    we have been discussing this quite a while on f1technical. We’ve also indicated that scraping the t-tray on the ground could be one of the causes. There is also a different theory: a couple of years ago you made an article about Red Bull super capacitors/resistors. Is it perhaps possible that they moved those to that exact t-tray area (for lower CoG) and is giving that heat signature? I don’t know if they are allowed to do so or not, but if so it seems quite plausible.

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  6. Craig, the first question obviously is why run it so close? With a small gap between the plank and the road there is a strong ground effect which should make the diffuser more effective….but as the gap closes air may be deflected away from the flow towards the diffuser. Be this as it may, I am wondering if this T tray hating is to control the attitude of the car (and the ground effect from the front wing) as the car pitches forward and down under brakes. In short is this a way of maintaining front wing legal compliance?

    • They run it so close in order to get the car set up with more rake, i.e. front ride height low and the rear ride height high. This makes the most of the front wing and diffuser.

        • There might be local stalling under the splitter just behind the tip, but such is the rake angle that plenty of flow can get under the plank further along the floor. But the benefit is the greater diffuser volume and lower front wing, which would offset the losses from the choking effect.

      • I wonder if by impeding the air from the center of the floor is beneficial in forcing a low pressure area there in order to prevent or to help the side leak ?
        Another thing is that as opposed to the oil the air viscosity increase with temperature so maybe it is beneficial to decrease the turbulence at the center… well it’s obviously very speculative…

  7. Could it be that heating the material will make it more flexible? While it is cold it is stiff enough to pass the FIA deflection tests. When racing, the grounding makes it hot and the tray will flex (some).

  8. Hi Scarbs
    It’s all very interesting, could the reason be as simple as some form of bi-metalic strip being used to lift the front of the T-tray as it heats up. I don’t know the elastic properties of Jabroc but, if this were possible, it would allow the T-tray to lower progressively as the fuel weight came off, thus keeping the car in optimum ‘ground effect’.
    I hope this makes sense! :-)
    Regards

    • again its possible, Jabroc is just wood, so that wont be the part that deflects differently with heat. its more likely to be the splitter support, but as I said in a previous comment, the car can be tested at any point so I doubt, this is an approach they would take.

  9. When I watched the FOM video, it appeared that the T-tray section became hotter during low-mid speed cornering and cooled off during the straights. So the front of the car is squatting during the corners…even if only for a couple of millimeters.

    Intuitively there would be more aero downforce on the car on the straights and high speed corners…but that force is not enough to cause the bottom of the tray to rub on the track. Naturally you’d see a bit of front squat under braking, but is that enough to generate the large heat blooms we saw on the camera? Or is RBR doing something else to increase the squat in low-mid speed corners to generate more downforce? Would we see the same thing looking at the t-tray of any of the other teams?

    • That could be an effect of the interlinked suspension, at low speed there is less downforce so the low front ride height is maintained. Then as speed and downforce builds up, the rear suspension will squat more and lift the front, keeping the splitter leading edge clear of the track

    • Its a big dense piece of metal, it will hold the heat for a long time. The splitter is a lot cooler in this pic than when on track.

  10. On Somers website there is a theory that the RBR9 has a bi-material construction as the splitter structural element, ie when the splitter gets hot it bends upwards, sounds plausible. This would be possible with low-expansion upper material bonded to high expansion lower material.

    Looking at this Sutton image from Monza..

    http://www.sutton-images.com/preview.asp?filename=dpl1306se001.jpg&search=13gp12b&index=934&count=966

    it seems that the ‘bracing strut’ has an incredibly thin section viewed from the front of the car, and appears to already have a slight buckle in the vertical plane. Furthermore it’s joined to the splitter at the lower end by a fastening method that doesn’t prioritise rigidity. Seems implausible that this is a device intended to resist the 2000N vertical load test, rather it looks to be deliberately weak to avoid detracting from a heated splitter curving upwards?

  11. I don’t understand this very much. I thought the Ti blocks were attached to the plank itself, which is made of wood. Do these Ti blocks heat up that much that can transfer heat through the wood? If we are seeing something around 100°, what is the temperature at the other side of the wood plank?

    • The Ti blocks sit in holes in the plank, but they are bolted up through the metal floor reinforcement. the heat is conducted through this connection.

  12. Would this hot lip on the front of of the tray help pre heat and energise/speed up the air travelling entering into and through the rake and help downforce?

  13. Thanks Scarbs, pretty much confirms what I was thinking, although I suspected it was ballast.
    I’m constantly working with hot metal, so depending on the material, mass and temp. it’s getting to, It would retain quite a bit of heat for a lot longer than most people think.
    The garage shot is the final confirmation, for me.

    • That’s a controversial point of view and one which I don’t subscribe to I have some more detail coming up on Red Bull’s splitter design which is less controversial and more substantiated.

  14. Hmmm. Is this one of the reasons McLaren were so desperate to sign Peter Prodromoi? And why RBR are so desperate to keep him for as long as possible!

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