Scarbs T-Tray proposal

[thisisatest]

In leymans terms if i nail a metal ruler to a table i have to include the weight of the table and use the table's rear legs as the pivot point, not the nail.
Only if the weight of the table is far greater than the force to have deflection in the ruler do i ignore it, as it wont have any significant motion compared to the ruler.

the weight of the table (car) IS much greater than the force to have deflection.
the car is approx 580kg, the FIA test is for 5mm or less deflection with a 200kg load applied.
with the see-saw arrangement, it may take 100kg, or less, to flex it up 5mm, which may be enough.

[kalinka]

the plank itself is not very stiff its 10mm birch plywood after all it is easily bend a few mm over a length of 1000mm.

Actulally, if understand correctly, in see-saw configuration, you doesn't even need a two-piece plank. It could be only one piece, and that lever is just presses down the plank at 1000mm from the front of the splitter. Of course if the mounting points of the plank are too close to the rear edge of see-saw tray, it would not work. In Monza pictures, I can't see where the plank should split in two, it seems to me it's one piece...maybe the line is just too thin to be seen.

[Richard]

In leymans terms if i nail a metal ruler to a table i have to include the weight of the table and use the table's rear legs as the pivot point, not the nail.

Ringo, I have empirically tested this.

I have put a 300mm ruler on the edge of my desk with 100mm projecting beyond the edge. I then pushed down on the projecting tip and the ruler rotated about the edge of the table. The table itself remained stationary. The ruler acted as a see-saw pivoting about the table edge.

I then placed my left arm over the entire length of the ruler and again pushed on the projecting tip with my right hand. The tip of the ruler deflected but the backspan under my arm did not move. The table did not move. The ruler acted as a cantilever with a rigid backspan.

This describes scarbs theory. The weight of the table is irrelevant as long as the self weight lever arm is greater than the test force lever arm.

ie (car weight * wheelbase/2) > (test load * distance from test loading to rear axle)

Given the test load of 200kg, car weight of 600kg, and wheelbase of 4m then equilibrium would occur when the test load was applied 6m from the rear axle.

Or, if the distance from the rear axle to test load was 3.5m then the test load would have to be greater than 342kg to lift the entire car.

[hardingfv32]

So the use of the "see saw" system is the reason for the one piece (floor and splitter) RB floor and the large hole at the front?

Brian

[scarbs]

I'll just post a quick update, as things have progressed over the past days.

Although independently conceived, the idea is definitely valid and has been used for years and is in use this year.

Firstly the FIA clarification came after a top team requested the design be considered as legal for their 2012 car. The team in question saw the post and copied concept with their own drawings. Citing the flex as useful for when kerbing the splitter, hence for safety/reliability reasons. The FIA forwarded their response to all the teams saying such a construction would be illegal and the test can be altered to prevent this practice. I have seen all the documentation to back this up.

I'm told the team saw the post backed up evidence from recent races and used their request to effectively protest the teams using it. This is a common approach in F1, to prevent confrontation between teams.

I've since heard that the design has been used by some teams since 2008 after the splitter saga between mac and ferrari, altered the splitter rules. The design is believed to be used by several teams this year.

I don't know the effect this will have at the next race. Perhaps none, perhaps some inspection of teams splitter designs, perhaps a change in the test. It might be a small gain for the teams using it and even without it the competitive order will remain.

But clearly this practice is on the teams and the FIAs agenda.

[myurr]

Thanks for the update - very intriguing that it is in use by more than one team. Makes you wonder how good a job the FIA are doing at policing the rules if such a system is in widespread use. What else are they missing, especially inside the car and under the floor?

[bill shoe]

The FIA can check for see-saw T-trays with their current test/deflection rig. Do the normal 200 kg deflection test, then continue to slowly increase the ram force to determine when the front of the car begins to lift off the rig (pitching the car up about the rear edge of the overall plank).

If there is no see-saw pivot point then the ram is effectively lifting the entire front of the car at the tea-tray and a force X is needed to lift it. X can be calculated from the empty car weight and C.G location, the location of the plank rear edge, and the location of the FIA ram relative to the other locations.

If there is a see-saw then the front of the car will lift off the rig when the ram force is less than X. The “missing” front lifting force would be provided by the reaction force at the rear edge of the see-saw. Therefore, a car might be declared legal if it stays on the test rig until the ram reaches at least 0.9 X.

I estimate that a car with an intentional see-saw would lift off the rig when the ram goes slightly over 200 kg, but a fully legal car (no see-saw or pivot) would stay on the rig until 300-400 kg.

The beauty of this test is that it checks for an effective pivot point. It does not require anyone’s interpretation of what is an explicit pivot or an allowable type of construction. If you fail this test then you have some kind of effective pivot, period.

[hardingfv32]

scarbs

"Although independently conceived" by you??

Brian

[bill shoe]

And holy crap Scarbs, good work!!!

[bill shoe]

scarbs

"Although independently conceived" by you??

Brian

I don't see the confusion here. He is saying that an F1 engineer didn't give him the idea over beers, that king of thing. If I had thought of something that clever then I would make it clear it was my independent thought.

[hardingfv32]

"Makes you wonder how good a job the FIA are doing at policing the rules"

The FIA is doing the job just fine based on the number of complaints you here out of the teams. Do you see the teams asking for better enforcement? Do you hear of ticket paying fans not coming to the tracks or lost race viewing being caused by the perception of poor rule enforcement?

The FIA is performing too the satisfaction of the participants in this area.

Brian

[hardingfv32]

"I don't see the confusion here. He is saying that an F1 engineer didn't give him the idea over beers, that king of thing. If I had thought of something that clever then I would make it clear it was my independent thought."

It is not clear to me. I think there could be a bit of modesty in not claiming the thought. I am trying to gage the level of his engineering creativity. I hold him in the highest regard.

Brian

[ringo]

In leymans terms if i nail a metal ruler to a table i have to include the weight of the table and use the table's rear legs as the pivot point, not the nail.

Ringo, I have empirically tested this.

I have put a 300mm ruler on the edge of my desk with 100mm projecting beyond the edge. I then pushed down on the projecting tip and the ruler rotated about the edge of the table. The table itself remained stationary. The ruler acted as a see-saw pivoting about the table edge.

I then placed my left arm over the entire length of the ruler and again pushed on the projecting tip with my right hand. The tip of the ruler deflected but the backspan under my arm did not move. The table did not move. The ruler acted as a cantilever with a rigid backspan.

Now imagine if that ruller was a 1 inch thick plate of steel, ie it has a very high stiffness. Wouldn't you agree that there will be no pivoting about the edge of the table?
The ruler would act as if it is one solid body with the table, and the table will lift about it's rear leg.

This exercise is to demonstrate that if the bending strenght of the floor and plank combined is so great enough, the force that is being applied to it will not bend the splitter, it will in fact have a tendency to simply push back on the whole car instead of deflecting one little section.
It is this approach that you would use to determine what kind of contact force with the floor you are experiencing and how weak the floor needs to be so that the force goes into deflecting the less stiffer floor than translating through the body.

This describes scarbs theory. The weight of the table is irrelevant as long as the self weight lever arm is greater than the test force lever arm.

No, you are ignoring the stiffness of the bodies.
This is numerical problem and its simpler talking about than actually anlayzing how to make it actually feasible.

ie (car weight * wheelbase/2) > (test load * distance from test loading to rear axle)

Given the test load of 200kg, car weight of 600kg, and wheelbase of 4m then equilibrium would occur when the test load was applied 6m from the rear axle.

Or, if the distance from the rear axle to test load was 3.5m then the test load would have to be greater than 342kg to lift the entire car.

You are ignoring stiffness. Is the body perfectly rigid? how can you prevent the force from acting through the whole body and only on the front splitter?
A la the table and the ruler, what are the conditions for the ruler to bend, and what are the conditions for it to be so rigid that it acts like a handle and the table lifts?

The ferrari bendy floor controversy is an extension of this.

[hardingfv32]

Why are you talking about bodies? Is the body from the floor section up? The RB has a separate floor assembly. Can it not bend without influencing the body? How could the body be affected?

Can an interior section of the floor assembly bend without the perimeter of the floor assembly being effected, say 5-6mm?

To be very precise, we are only concern about the movement of the plank as the is the only part check for wear.

I do not understand your concerns. Can you clarify?

Brian

[thisisatest]

Now imagine if that ruller was a 1 inch thick plate of steel, ie it has a very high stiffness. Wouldn't you agree that there will be no pivoting about the edge of the table?

if that was the case, the test load of 200kg would be deflecting the splitter 0.01mm, not something near 5mm. although not stated, it has been implied that the splitter is flexing with the test load, but passing as its flex is less than 5mm. it is almost a given that if the floor is then removed of constraint (by the test surface) and a pivoting arrangement is present, then the same force would flex the splitter a lot more...