2018 Aerodynamic Regulations Thread

[Vyssion]

Hi all,

As I did last year with all the 2017 massive aerodynamic overhaul of the regulations, here is a summary with associated images of the changes to aerodynamic devices fort the 2018 season. Sorry I am a bit late with it, I was on holiday

Within the official FIA regulations, Article 3 pertains to bodywork and dimensions with references to aerodynamic parts within it. Lets go through it in broad strokes for most of it since 2018 has very few changes relative to 2017.

ARTICLE 3 : BODYWORK AND DIMENSIONS

3.1 - Definitions
Unchanged from 2017

3.2 - Overall Dimensions
Unchanged from 2017



3.3 - Front Wing
Change to section 3.3.2 which governs the "Mandatory Central Section" in that a 2mm tollerance is now permitted for manufacturing purposes and is stated that this should not be used to allow for an illegal design.
Other changes are purely just reordering of wording etc.



3.4 - Front Bodywork
New plane C-C defined as the rear of the cockpit which was followed by a slight change to the exclusion area postion closest to the front of the cockpit opening, presumably to accomodate the halo.
Other than that, no change.





3.5 - Rear Bodywork
Change to the engine cover definition within 3.5.1 which stats that:
"When viewed from the side, no bodywork forward of the rear wheel centre line may lie above a line parallel to the diagonal boundary defined in a) and intersecting the rear wheel centre line 650mm above the reference plane."
This is the removal of the shark fin and T-wing.
Other than that, there are only minor updates to terminology and "quality of life" clarifications etc.










3.6 - Rear Wing and Rear Impact Structure
Change to section 3.6.5 clarrifying about Rear Impact Structure which states:
"With the exception of the last 150mm of the tailpipes described in Article 5.8, there must be no bodywork in an area less than 100mm from the car centre plane, more than 200mm behind the rear wheel centre line and between 400mm and 550mm above the reference plane."
This is because this year, the tail pipes from the engine have increased in length which protrudes by a small proportion into what would otherwise be an exclusion zone.






3.7 - Floor and Diffuser
Change to the plank material in section 3.7.10 from a bonded assembly to a homogeneous material with a slightly tigher specific gravity specification (on the lighter side). This is unless it is pocketed, in which case the specification reverts to the old one with clarification of a homogeneous material only.




3.8 - Aerodynamic Influence
Unchanged from 2017

3.9 - Bodywork Flexibility
Unchanged from 2017

3.10 - Bodywork Construction
Unchanged from 2017

ARTICLE 15 : CAR CONSTRUCTION
Lastly, the dreaded "Halo"...
15.2 - Roll Structures
"The secondary roll structure, which is not considered part of the survival cell, must be positioned symmetrically about the car centre plane with its front fixing axis 975mm forward of the plane C-C and 640mm above the reference plane. The mounting faces for the rearward fixings must lie on a plane parallel to and 675mm above the reference plane.
The driver's helmet and steering wheel must be arranged such that they lie below a line drawn between the front fixing axis of the secondary roll structure and a point 75mm vertically below the highest point of the principal roll structure."
"The secondary roll structure must be supplied by the FIA designated manufacturer. Details of the structure and its mountings may be found in the Appendix to the Technical Regulations."


There are a few things to be said about this Halo...
Firstly, the teams are allowed to paint the halo whatever colour that they want.
Secondly, they are also allowed to "wrap" the halo in a 30mm fairing to try and tidy up the air around it whilst (I hope...) also making it more aesthetically pleasing...
Considering that the halo is right in the way of the air flowing over the nose of the car and then around the engine cover, it will most likely hinder the efficiency of the intake of clean air into the engine unit, along with the quality of air that the rear wing receives from the engine cover once it has past it. There is also a ~20kg increase in weight as well.
Due to wanting to reduce drag as much as possible, we may see a sort of "minimalistic" approach to the shrouding of the halo. The tubings downward slopes will induce a small amount of lift, but this may be mitigated by the fairings.
Depending on how well the teams are able to manage the specified mounting points of the halo at the rear of the chassis, there may be potential to use the sides of the structure as a downwash device over the top of the sidepod to induce a pair of vortices to play some part at the rear of the car - whether to virtually seal, feed some aerodynamic device or whatever. 30mm of fairing is tight to try and do this, but there is potential for vortex generation and management.
It's position close to the centre of mass means that it should be fairly neutral in terms of weight bias, but its mounting at the top of the car will see a roll centre height increase.
The main issue going forward, and why I dont think there will be too much difference in designs going forward, will be that the halo is in a position where you just really dont want to manipulate the airflow...

Anyways, I hope that this helps you all to get a better sense of the changes (or lack thereof!!) for the aerodynamics 2018 regulations. As always, enjoy this year's season!!

[turbof1]

Stickied

[turbof1]

I also read that the teams are not allowed to paint the side of the halo pointed towards the driver, this to avoid drivers being distracted from too bright colors. Don't know if that is in the regulations, or if that is a technical directive.

[roon]

The last big aero-formula change was in 2009. That was the year we saw the DDDs (double-deck diffusers), due to an overlooked regulatory loophole. In 2017, we saw the introduction of T-wings, also due to an overlooked regulatory loophole. But the T-wing is no DDD.

2010 was the year of the F-duct, one of the more exotic features to make its way onto the cars in recent years. In 2018, after a year of familiarizing themselves with the new formula, perhaps we'll see some similarly unique developments.

[dans79]

while not a 100% technical question, can someone explain what the hatred of the shark-fin is about?

So many people seemed hell bent on getting rid of what to me seems like a very simple aero appendage.

[OO7]

while not a 100% technical question, can someone explain what the hatred of the shark-fin is about?

So many people seemed hell bent on getting rid of what to me seems like a very simple aero appendage.

It's simply because most people find it ugly.

[Vyssion]

while not a 100% technical question, can someone explain what the hatred of the shark-fin is about?

So many people seemed hell bent on getting rid of what to me seems like a very simple aero appendage.

There are a few disadvantages of the shark-fin from a performance stand point. Mercedes (back when the last time shark fins were employed) actually found, through studies, that the shark-fin disrupts the air to the rear wing in a straight line and negatively impacts performance to the tune of around ~3%. I would be surprised if that value was still that high (more to the tune of 0.5% or 1% nowadays) but still. Now, given a few degrees of tyre slip angle for your yaw case would drastically favor the shark-fin being there for the yaw-stability.

There is also the issue that, under cornering, the edge vortex that rolls up over the top edge may hit your rear wing surface; if it does so, it will disrupt flow and negatively affect performance. You can solve this by having a lower situated rear wing to try and cause that vortex to be directed up and away from the wing surface by the wing's pressure field.

Even the side-force that it generates... aside from over-steer correcting, under normal high speed cornering where your turn in angle is only a few degrees (maybe like 5° at most?) you wont really see that pronounced an effect on your maximum cornering G-force. That's presumably why teams like Mercedes were able to run 2017 without the use of a big fin - there just wasn't really enough of a gain to be had vs. whatever else they may have been doing (i.e. body panel sculpture promoting its own side-force or something else entirely).

I vaguely remember hearing someone from a team on TV saying that, in their opinion, the fin just "complicated" things and was another thing to manage as well.

[roon]

while not a 100% technical question, can someone explain what the hatred of the shark-fin is about?

So many people seemed hell bent on getting rid of what to me seems like a very simple aero appendage.

There are a few disadvantages of the shark-fin from a performance stand point. Mercedes (back when the last time shark fins were employed) actually found, through studies, that the shark-fin disrupts the air to the rear wing in a straight line and negatively impacts performance to the tune of around ~3%. I would be surprised if that value was still that high (more to the tune of 0.5% or 1% nowadays) but still. Now, given a few degrees of tyre slip angle for your yaw case would drastically favor the shark-fin being there for the yaw-stability.

There is also the issue that, under cornering, the edge vortex that rolls up over the top edge may hit your rear wing surface; if it does so, it will disrupt flow and negatively affect performance. You can solve this by having a lower situated rear wing to try and cause that vortex to be directed up and away from the wing surface by the wing's pressure field.

Even the side-force that it generates... aside from over-steer correcting, under normal high speed cornering where your turn in angle is only a few degrees (maybe like 5° at most?) you wont really see that pronounced an effect on your maximum cornering G-force. That's presumably why teams like Mercedes were able to run 2017 without the use of a big fin - there just wasn't really enough of a gain to be had vs. whatever else they may have been doing (i.e. body panel sculpture promoting its own side-force or something else entirely).

I vaguely remember hearing someone from a team on TV saying that, in their opinion, the fin just "complicated" things and was another thing to manage as well.

FI and Williams had rows of teeth and gurney tabs, respectively, running along the top of the shark fins. Do you think this was to weaken yaw formed vortices, or perhaps simply a way produce a little more downforce? Maybe a way to keep flow attached on the outboard side when cornering? By inducing vorticity on the LP side of the fin.

Flow through that area is interesting. In a straight line there would be on a downward trajectory following the general downward slope of the engine cover. Hence why the winglets that sprout up in that area appear to have an upward, lift producing appearance. Under yaw, flow through that area may/may not be reversing to flow upward on the HP side, spilling onto the LP side. I assume the former, but not sure.

[Vyssion]

FI and Williams had rows of teeth and gurney tabs, respectively, running along the top of the shark fins. Do you think this was to weaken yaw formed vortices, or perhaps simply a way produce a little more downforce? Maybe a way to keep flow attached on the outboard side when cornering? By inducing vorticity on the LP side of the fin.

Flow through that area is interesting. In a straight line there would be on a downward trajectory following the general downward slope of the engine cover. Hence why the winglets that sprout up in that area appear to have an upward, lift producing appearance. Under yaw, flow through that area may/may not be reversing to flow upward on the HP side, spilling onto the LP side. I assume the former, but not sure.

My understanding of the Force India winglet ones were that "loosely", they were there to help increase load at the rear of the car, as well as better direct airflow to the T-wing and rear wing.



As for the Williams with it's gurney flap, typically a gurney needs to be large enough to extend just beyond the boundary layer which forms on the surface it is mounted on. The aim of a gurney flap is to create a small stagnation pressure on the top of a downforce generating wing in the form of a vortex which then sheds over the top of the flap alternating from one shed off the lower side of the aerofoil. Basically, you would see this effect come into play to increase slightly the maximum cornering g-force. Althought to what magnitude, I have no idea beyond saying "it would most likely increase it slightly".

[krisfx]

while not a 100% technical question, can someone explain what the hatred of the shark-fin is about?

So many people seemed hell bent on getting rid of what to me seems like a very simple aero appendage.

It's simply because most people find it ugly.

I don't recall people finding them ugly/media outcry on their looks in 2008 or 2010! Opinions do change over time, though I guess.

I think fans always need something to moan about and never seem happy with the regs. 2009-16 "not enough downforce, it's boring" 2017-"Too much downforce, it's boring".

The T-Wings could have been solved by simply closing the small box in the regs and I think the shark fins would've stayed. I for one don't really care, I just think it's interesting.

[Vyssion]

Couple of shots of the Halo on the Mercedes car.

[GM7]

With the Halo introduction in 2018, is the green part becoming "useless" ?

[jjn9128]

With the Halo introduction in 2018, is the green part becoming "useless" ?

No that part of the car remains as important as ever for driver safety. It's foam covered by kevlar for impact attenuation. The foam used is even specified by FIA depending on the air temperature - they have pink and blue variants, but I can't remember which is used when.

[Just_a_fan]

With the Halo introduction in 2018, is the green part becoming "useless" ?

https://image.noelshack.com/fichiers/20 ... -crash.png

No, the raised section prevents excessive lateral flexing of the driver's neck in lateral accidents.

[mclaren111]

With the Halo introduction in 2018, is the green part becoming "useless" ?

https://image.noelshack.com/fichiers/20 ... -crash.png

I think it would be great if it is removed. Just adapt Halo's points of attachment slightly !! Does the same job