TD039

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organic
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Re: TD039

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carisi2k wrote:
Tue Sep 06, 2022 7:20 am
AR3-GP wrote:
Mon Sep 05, 2022 7:27 pm

TD039 introduced the AOM metric.
No TD039 was about the plank flexing 6mm and the measurements holes and not the measurement of aerodynamic oscillation which is a different TD.
It was all pushed through under the same TD, TD039

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vorticism
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Re: TD039

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Does anyone have a copy of TD039?

If I was going to flex the floor I might start with the firewall. What's to prevent a team from making a rear chassis face (the rearmost fuel cell wall) which can flex? The floor test would not show anything since they only span either side of this mounting face. To test for it you need to apply a force above the firewall f.e. through the roll hoop and measure any bowing of the chassis.

For the Ferrari which might have its COP more near the middle as Vanja pointed out in another thread we would have the low pressure region of the floor acting as the downward force which could bend the engine into the firewall. Depending on suspension geometry and rake this then could provde some extra ground clearance either fore or aft of the deflection center.

Conversely, if the front and rear wings, being beyond wheel centerline, could provide enough force to bend the weak point in the center of a chassis, the floor could then bend up instead of down, which when combined with slight rake might help ensure the middle of the plank doesn't touch the ground.

caddy
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Re: TD039

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As none of the online articles are clearly spelling out what TD039 is, I thought of posting this here too, as I posted in FIA thread.

Most online articles are mixing up TD039 with porpoising metrics and saying that, TD039 is issued to stop porpoising, which is incorrect. FIA had suspicion that some teams are exploiting the plank stiffness grey area and issued the TD to address it. Here is the link to the document and the relevant update.

https://www.fia.com/sites/default/files ... -08-16.pdf
Convention:
Black text: All text from previous versions of the regulations
Pink text: Changes approved by the WMSC on 16 August 2022

3.15.8 Central Floor Flexibility
a. Bodywork within RV-PLANK may deflect no more than 2mm at the two holes in the
plank at XF=1080 and no more than 2mm at the rearmost hole, when the car, without
driver, is supported at these positions. The car will be supported on 70mm diameter
pads, centred on the holes, and only in contact with the underside of the plank
assembly. The displacement will be measured at the supports, relative to the
reference plane at the centre of each hole.
Furthermore, the stiffness for any load exceeding that defined in the previous
paragraph must be no less than 15kN/mm.
Competitors will be required to demonstrate the local vertical stiffness and design
installation of the skids and plank to the FIA for the regions around the periphery of
each of these three holes. Compliance with Article 3.5.9.e. will only be assessed in the
regions that are at least 90% as stiff as the stiffest part of the periphery. Any designs
intended to protect these regions of the periphery from wear will not be accepted.
Competitors will be required to demonstrate compliance with these provisions by way
of a detailed inspection of both the CAD and the physical installation, as well as Finite
Element analysis.
My guess as to why they call it TD039 is that, Plank Reference Volume is listed as 39th Reference Volume in the Technical Regulations and hence, TD039 is a technical directive that clarifies the Reference Volume 39, which is Plank Reference Volume (RV-PLANK).

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JordanMugen
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Re: TD039

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vorticism wrote:
Fri Sep 09, 2022 8:10 pm
What's to prevent a team from making a rear chassis face (the rearmost fuel cell wall) which can flex?
That's what the engine and gearbox (i.e., the rear end of the car) is attached to. Why would you want to make your whole car floppy, wouldn't that make it handle horribly? :wtf:

graham.reeds
graham.reeds
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Re: TD039

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It could make it bounce up and down...

Seriously though, if you can design a front wing to flex enough that it dramatically sheds downforce but strong enough that it passes the FIA tests then you can probably design a chassis that has a little flex to allow the bottom to reach lower to the floor.

marcel171281
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Re: TD039

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graham.reeds wrote:
Tue Nov 29, 2022 2:24 am
It could make it bounce up and down...

Seriously though, if you can design a front wing to flex enough that it dramatically sheds downforce but strong enough that it passes the FIA tests then you can probably design a chassis that has a little flex to allow the bottom to reach lower to the floor.
Have you ever driven an old Saab convertible?

The front wing isn't a structural part of the car. The tub however is the most important structural part of the lot. You want an absulute minimum of any form of deformation in that part as it will effect every other element of the entire car, both in terms of geometry and aero.

BTW the wing isn't part of the FIA crashtest, the nose cone is. Nose cones don't flex.

graham.reeds
graham.reeds
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Re: TD039

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marcel171281 wrote:
Tue Nov 29, 2022 1:22 pm
graham.reeds wrote:
Tue Nov 29, 2022 2:24 am
It could make it bounce up and down...

Seriously though, if you can design a front wing to flex enough that it dramatically sheds downforce but strong enough that it passes the FIA tests then you can probably design a chassis that has a little flex to allow the bottom to reach lower to the floor.
Have you ever driven an old Saab convertible?

The front wing isn't a structural part of the car. The tub however is the most important structural part of the lot. You want an absulute minimum of any form of deformation in that part as it will effect every other element of the entire car, both in terms of geometry and aero.

BTW the wing isn't part of the FIA crashtest, the nose cone is. Nose cones don't flex.
I never said crash test. The FIA does loading tests with weights on the wings to measure deflection. That was the test I was referring to.

marcel171281
marcel171281
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Re: TD039

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graham.reeds wrote:
Thu Dec 01, 2022 7:40 am
marcel171281 wrote:
Tue Nov 29, 2022 1:22 pm
graham.reeds wrote:
Tue Nov 29, 2022 2:24 am
It could make it bounce up and down...

Seriously though, if you can design a front wing to flex enough that it dramatically sheds downforce but strong enough that it passes the FIA tests then you can probably design a chassis that has a little flex to allow the bottom to reach lower to the floor.
Have you ever driven an old Saab convertible?

The front wing isn't a structural part of the car. The tub however is the most important structural part of the lot. You want an absulute minimum of any form of deformation in that part as it will effect every other element of the entire car, both in terms of geometry and aero.

BTW the wing isn't part of the FIA crashtest, the nose cone is. Nose cones don't flex.
I never said crash test. The FIA does loading tests with weights on the wings to measure deflection. That was the test I was referring to.
I misread (minor form of dyslexia here).

But still, flexing wings or not, flexing chassis? Too unpredictable in too many area's. Imagine doing calculations and designing a suspension where the pickup points of are not a stable factor, because the main thing they're connected to starts moving around depending on loads and speeds. As the floor is a seperate piece only bolted to the rest of the car when everything is already in place, it is much simpler to get the desired effect by making the floor itself flexing relative to the tub.