Scarbs T-Tray proposal

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hardingfv32
hardingfv32
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Re: Scarbs T-Tray proposal

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What are the chances of that? We are talking about hitting track irregularities and curbs, not constant contact. We need frame by frame slow motion video. I was trying to make something out of a video of the a McLaren hopping in a brake zone or something in Australia. Very dramatic, but there was no way to get good stop frame information and make useful observation of the splitter's actions.

There have been such video sequences in the past during F1 broadcasts.

Brian

myurr
myurr
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Joined: 20 Mar 2008, 21:58

Re: Scarbs T-Tray proposal

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ringo wrote:why is the middle worn?
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Is the middle flexing?
Ironically this better reflects the see saw than the redbull.
The tip is clean as if the front see sawed upward, and the middle is scrubbed as if the other side of the see saw came down, Akin to richard leeds drawings.

This really, is no different than the redbull in the cuase of the wear. Uneven surfaces and debris. Different suspension setup,different wear.

The redbull's doesn't maintain it's rake under braking, the floor has some flex beyond the forces experienced during the test, and that is the explanation.

The horse thing was a joke by the way. It was reflecting on the whole basis for the see saw.
Ringo you've got to be doing this deliberately. That plank is nothing like the Red Bull and you know it. The scuff marks on the Williams will be different every single time, and there are no patches of extreme wear. And this is after a full race distance.

Mark Webber only completed 8 laps in Valencia and already we could see very strong wear patterns on the plank of his car that have been consistent on all pictures of the Red Bull plank.

Even if the Red Bull is massively changing rake under braking (and it really isn't - the forces involved would actually increase rake, plus under braking is when you want rake as it will increase downforce and drag) then you would see wear more like the Williams.

All I can conclude is that you want the Red Bull to not have a flexing t-tray so much that you're just wilfully blinding yourself to any and all evidence and trying to carpet bomb the forum with your opinion presented as fact with nothing to back it up.

Richard
Richard
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Re: Scarbs T-Tray proposal

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Ringo, I think you've misread what I've been saying.

The reason for lifting the tray relative to the reference plane is so the front wing can be lower. This means the tray is set to be parallel to the ground while the rest of the plank is high in the air.

It's not a new idea, here my sketch from August 2010 viewtopic.php?f=6&t=8764&start=585

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The Williams is an example of a straight plank with wear in patches along its entire length from running over kerbs.

In my mind this is very much about how the FIA measure tolerance and wear. The car sitting on the test rig provides a 550kg clamp to straighten the plank with tolerance. I'll drop a PM to Scarbs to see is he knows how the tolerances are measured.

Flex is a distraction, the tray has to be stiff enough to not move flapping on track because that would mess the under floor air flow.

There are 2 simple ways to check this without requiring teams to redesign stiffer floors:

1 - Place a wear inspection hole in the middle of the tray - it only need a hole cutter from a DIY store.

2 - Measure floor tolerance with the car weight supported on its wheels.

Both can be implemented in a matter of hours.

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ps - This is all about getting the tray and front wing as close to the ground as possible. A team with a straight plank would have to put the rear very high in the air to get the front wing down, that would stall the diffuser. A team with curved plank could get the front wing down without having to lift the rear too much.

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p.p.s Here is Webber's car from Valencia 2010. The wear is more even than this year, but most of it is in the front half. It looks tame compared to this year but even that distribution raised eyebrows in 2010.

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Reca
Reca
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Joined: 21 Dec 2003, 18:22
Location: Monza, Italy

Re: Scarbs T-Tray proposal

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To have a further comparison, this is Massa's car after he retired in Barcelona race, with handful of laps to go:

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Wear in the first part only, pattern that you would expect on a car with flat underfloor running with a bit of rake, thus making occasional contact with ground on area just behind leading edge.

hardingfv32 wrote:
myurr wrote: Could be that the Red Bull stay is being used to pull the bib up to give it a non-flat bottom and allow lower ride height, and then is simply removed when tested.
No... The car will be tested as raced when the flatness of the reference plane is tested, +/- 5 mm.
Fine, which means at worst we have 8-9mm (depending on how safe you want to be) to play with, over a distance of about 660-670mm from the suspected pivot. Not much, but still useful when ride height adjustments are measured in millimeters.

BTW, do you know how exactly that "flatness" of the floor is effectively measured?
Is it done with the car suspended on wheels or they put it down on the rig and check it makes contact for the whole length?

If you look at these pics from scrutineering:
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it seems bodywork measurements are done without wheels and car down on rig (at least, the "mask", or whatever it's called in English, used to check rear wing legality works only once wheels are removed and car is lowered), but besides these or similar pics I've no specific details on how each test is done and which instruments are used by FIA.

It's fundamental to know these things as the solution we are all seeking is apparently down to fully exploiting these details. (with the obvious consequence that it would take just a small change of testing procedure to expose the trick, but it's a small risk as FIA changes procedures only after having warned teams and typically after rumors about something odd going on have reached the press already, it can take several months, if not years, meaning several races...)

Maybe the flatness of floor is measured before removing wheels, and rest of measurements are done after that, or maybe everything is checked only once car is supported by the rig. At the moment I don't know and lacking that info it's not possible to give a definitive answer about what is and is not possible to do to pass the test.

For example, if flatness of floor was measured with car resting on the rig, you could pass the test, even with stay in place.
The rod would have just to stretch a bit, to let front of splitter drop enough for floor to be flat within required tolerance in the moment the car is put on the rig (thus with additional traction applied on it by virtue of the see-saw design), while keeping the splitter some further mm up when more lightly loaded on track. Is that impossible to do with a slim rod correctly pretensioned? Remember we are talking millimeters here, not 5cm.

This is just a theoretical example to make the point that, as I said, the perfect knowledge of the details of the tests made by FIA is needed to discard/accept any of the suggestions made in this thread, reading the rules is not enough (especially as the rules available on fia.com aren't complete, mostly a summary lacking all the clarifications, correspondence FIA/teams, updates and so on).

Richard
Richard
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Re: Scarbs T-Tray proposal

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Massa's car looks odd. Normally the plank starts dark and the worn parts are lighter. That means no wear at all on Massa's tray but lots of wear on the rest?

Reca - your comments about tolerance are in line with what I've been thinking. This is about exploiting tolerances over the length of the tray in order to increase the rake of the car. I've asked Scarbs if he knows how the floor tolerances are measured.

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hollus
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Re: Scarbs T-Tray proposal

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In the Ferraris, the plank starts light when new and darkens when worn. See the same plank from behind, the rear is immaculate:

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The material choice is free, so I guess they are using a different type of wood.
Rivals, not enemies.

hardingfv32
hardingfv32
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Re: Scarbs T-Tray proposal

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"Massa's car looks odd. Normally the plank starts dark and the worn parts are lighter. That means no wear at all on Massa's tray but lots of wear on the rest?"

1) You are working with two tolerance, one for the reference plane and one for the floor. As stated earlier a range of 2.98 mm for the plank and 11.98 mm for the reference floor for a total of 14.96 mm.

If we state that the distance from the leafing edge of the plank to just in front of the 750 mm test holes is 700 mm, using the above tolerances you get an angle of 1.22 deg. Extending this 1800 mm back to the end of the plank, you get the end of the plank raised 38.33 mm (assuming the splitter is flat to the ground).

This is only half way to the rake that I estimate RB has while static in the pits.

The plank would need to be remove from the floor to get a precise measurement of the reference plain.

2) Normal plywood could have layers of darkness where the bonding material is. IF this is Jabroc, they use pressure and high temps during the cure process, so maybe the bonding material permeates the wood layers more than a normal plywood lay-up. But, you are correct that the Massa floor is odd and hard to explain.

Brian
Last edited by hardingfv32 on 24 Oct 2011, 21:05, edited 3 times in total.

hardingfv32
hardingfv32
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Joined: 03 Apr 2011, 19:42

Re: Scarbs T-Tray proposal

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"BTW, do you know how exactly that "flatness" of the floor is effectively measured?
Is it done with the car suspended on wheels or they put it down on the rig and check it makes contact for the whole length? "

Ideally you would place the car floor in proximity of a granite surface plate and make your measurements. This is not going to be practical at the track.

Are there "portable" laser systems that travel along a very precise track that could make the measurements required? The accuracy of the laser's movement might need to be on the order of 1000th of a mm.

Brian

bill shoe
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Re: Scarbs T-Tray proposal

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This is a good quality discussion about how to define and measure a reference plane. This discussion has convinced me that the current FIA method is no good in general, not just with regards to the Scarbs' T-tray trick.

The current FIA test rig lifts the car up on a flat plate so the wheels are off the ground. This flat plate itself, NOT the underside of the car, effectively becomes the reference plane. Other dimensions (bodywork limitation dimensions, etc.) are effectively taken relative to the FIA rig plate. It's implicitly assumed that the FIA plate and the car underside are one and the same. However, the T-tray see-saw and other issues discussed in this thread make it clear these concepts are not identical when the car is on the test rig.

Here's how to measure a reference plane that corresponds to actual car behavior on the track. Roll the car on a flat plate and don't lift it!! The car is still supporting its own weight through its wheels. Have a system of laser sensors under the car to measure the topology of the underside and plank, WHILE the car sits on its wheels. Then a relatively simple computer algorithm can determine the virtual location of the reference plane. Other measurements will have to be taken with lasers and/or other high-precision measurement probes, and will then be compared to the virtual reference plane to determine legality.

Load testing for component rigidity (such as t-tray deflection) is more complicated but still follows the same general idea. The t-tray ram pushes up against the appropriate location with the appropriate force. Then the laser system under the car scans again to determine the new reference plane location (the reference plane has presumably moved up due to suspension unloading). Then the deflection at the front of the t-tray is compared to the new virtual reference plane to determine legality. T-tray see-saws and other clever tricks would instantly fail.

This system with laser measurement and virtual positioning is clearly more complicated than the current approach with a lifting plate and dimensional pass/fail fixtures. However, I think it is not possible to do a relevant measurement with a lifting plate that corresponds to meaningful on-track car properties. It turns out the FIA was being a naive for several years (since ~2008 according to Scarbs) and the greater sophistication and complexity of the virtual system is necessary. The teams are too clever for anything else.

bill shoe
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Re: Scarbs T-Tray proposal

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Yes, the virtual measurement post above was sparked by Brian's mention of laser sensors. Yes these sensors exist with necessary resolution and are practical to implement at the track. The FIA might have to sell one of their motorhomes to pay for the new test rig, but creating and enforcing rules is their core mission.

Robbobnob
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Re: Scarbs T-Tray proposal

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Image

The two expansion zones on the RB7 splitter are interesting.

They would create a higher pressure differential, possibly aiding a sea saw movement of the Splitter
"I continuously go further and further learning about my own limitations, my body limitations, psychological limitations. It's a way of life for me." - Ayrton Senna

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pocketmoon
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Re: Scarbs T-Tray proposal

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kalinka wrote:And wow ! I think we'll never get a better view >

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So many questions arise from that image :) Three of the mandatory 'inspection' holes can be seen. The pair of 80mm holes are 750mm from the front, so if the plank is in three sections the shortest point it can end beyond those holes is another 250mm.

But there are 11 fixings on the front, worn, section alone and only two visible in the shot beyond the ref hole pair. The splitter is

The regs say that if you have more than 10 fasteners then the rest "may be no more than 8mm below the reference plane". So may be 2mm or more indented. So could the wide unworn section be a 'hole' cut to accommodate two recessed fastening ?? It's a bloody big hole if it is :)

Finally, does the plank have to be straight ? Could the front section be lifted by the connector that's visible between the t-tray and the body ? The pattern of holes/fastenings underneath could indicate a natural bend - the ample line of fastenings required to stop the plank curving away from the t-tray under upwards tension (the plank is going to want to form a curve while the t-tray is origamied to enable a sharper bend)


I'm a nube at this so open to being educated!

Cheers

Rob

p.s. RB6

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ringo
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Re: Scarbs T-Tray proposal

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You raise some good points, and as you say this is one single piece with wear on it.

Now this is not different than the ferrari. In fact it's more linear.
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Let's honestly look at how far the wear is and how even it is.
The Redbull is actually more worn in the yellow circles. The tip is more worn than anywhere else. which is what was being pointed out.
The blue is where we have mostly black, unscrubbed floor.
The streaks are just there from Webber's outing. Everyone agree that the yellow circle at the front has the most wear?

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The ferarri has a more flatter wear patten in the front than the redbull. In fact it looks like the ferrari sits on the splitter more than the Bull.

We might as well be looking at the size and shape of a driver's sweat patches on his uniform to figure out how much effort he exerts to drive, and thus how much downforce the car has by virtue at it's ease to drive.
Looking at these patterns are far from conclusive about a fabled system.
For Sure!!

hardingfv32
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Re: Scarbs T-Tray proposal

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1) "So could the wide unworn section be a 'hole' cut to accommodate two recessed fastening ?? It's a bloody big hole if it is"

It would be my opinion that "no wear" area is not a machined hole. If you look closely at that two fastener inside this area, they seem to have the same countersunk look to then as seen with other fasteners. Tech could consider the larger "hole" as not part of the individual mounting hole shape.

2) "does the plank have to be straight ?"

The reference floor that the plank is mounted to has to be flat, +/- 5 mm. So the plank could be curved with in this tolerance.

3) "Could the front section be lifted by the connector that's visible between the t-tray and the body ?" Not sure there is any benefit to this. What was your thought? Remember, it probably must be tested in a pull up condition if that is how it is raced.

Brian

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flynfrog
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Re: Scarbs T-Tray proposal

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chupacabra

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