2018 McLaren F1 Team - Renault

[KingHamilton01]

So in other words had to put more wing on at the expense of top speed???

[diffuser]

Seems atleast some of the problems was that their CFD didn't work anymore after the formula changes in 2017.

[JordanMugen]

That clears it up then (?).

Lol. From what I can gather, the problem could be diffuser stall / loss of efficiency due to the wheel wakes leaking under the floor, especially during low to medium corners where there are larger slip angles -- high speed corners with small slip angles were apparently less effected.

At 3.55m, McLaren's wheelbase is one of the shortest^. The easiest solution: to change to a long wheelbase car that is less sensitive. I take it that it was changing to a long wheelbase car during the season was not feasible (due to the need to re-engineer the gearbox case and so on)?

^ Of course the other solution would be to retune their existing front wing, snowplough and bargeboards so the diffuser doesn't stall at large yaw angles --- but this might be asking too much!

The other issues like the outdated idea of a small airbox intake & empty space not being used efficiently under the air intake (where others have intercoolers and so on), not using the popular "double wing" style sidepod crash structures, the incorrect gear ratios -- these (while not helpful) were perhaps not the main problem.

So in other words had to put more wing on at the expense of top speed???

Yep. They put the extra wing on to cover up for the ineffective diffuser downforce. Since, of course, the rear wing (in particular) is not sensitive to wheel wakes during yaw unlike the floor.

Another small help from the rear wing's low pressure driving the diffuser too.

But overall: not good. Not making downforce with the same efficiency as the rival Red Bull team. Nowhere close even...

[M840TR]

That clears it up then (?).

Lol. From what I can gather, the problem could be diffuser stall / loss of efficiency due to the wheel wakes leaking under the floor, especially during low to medium corners where there are larger slip angles -- high speed corners with small slip angles were apparently less effected.

At 3.55m, McLaren's wheelbase is one of the shortest^. The easiest solution: to change to a long wheelbase car that is less sensitive. I take it that it was changing to a long wheelbase car during the season was not feasible (due to the need to re-engineer the gearbox case and so on)?

^ Of course the other solution would be to retune their existing front wing, snowplough and bargeboards so the diffuser doesn't stall at large yaw angles --- but this might be asking too much!

The other issues like the outdated idea of a small airbox intake & empty space not being used efficiently under the air intake (where others have intercoolers and so on), not using the popular "double wing" style sidepod crash structures, the incorrect gear ratios -- these (while not helpful) were perhaps not the main problem.

So in other words had to put more wing on at the expense of top speed???

Yep. They put the extra wing on to cover up for the ineffective diffuser downforce. Since, of course, the rear wing (in particular) is not sensitive to wheel wakes during yaw unlike the floor.

Another small help from the rear wing's low pressure driving the diffuser too.

But overall: not good. Not making downforce with the same efficiency as the rival Red Bull team. Nowhere close even...

You're probably right. According to the AMuS article Stella mentions tyre wake management as an issue, which effects diffuser downforce. But if the car is good in high-speed corners and not in low-speed ones, then the stall is during pitch not yaw.
They also kept modifying the turning vanes, FW and bargeboards throughout the year but without luck.

[Dipesh1995]

Hmm so if their weakness is low/medium-speed corners then it begs the question as to why were they quick in Singapore (best of the rest) and reasonably quick in Monaco? Imho, I think the car was particularly lacking in medium/high-speed corners and therefore they ran more wing to compensate for this which exposed them down the straight. At tracks where there were low-speed corners and short straights, teams ran with as much wing (downforce) as possible (although these kind of tracks more dependent on mechanical grip but any bit downforce helps obv) which helped neutralise McLaren’s woes. At tracks where there were reasonably long straights and many medium/high-speed corners such as Suzuka, Austin etc, that is where they struggled the most because they could not take enough of wing off, certainly not as much as their rivals could, without struggling around the corners forcing them to run with more wing to point where they were still not quick enough through the corners but also were sitting ducks on the straight.

As for their car’s certain aerodynamic characteristic that they could not replicate in the WT, teams are able to do a lot in the WT but one thing they cannot do is replicate true cornering conditions accurately via curved flow where the yaw angle relative to the flow changes locally rather than being a constant thus affecting flow structures, direction of wheel wakes etc. With this in mind, is there a possibility that this was the source of their problem(s)?

[RonDennis]

Hmm so if their weakness is low/medium-speed corners then it begs the question as to why were they quick in Singapore (best of the rest) and reasonably quick in Monaco? Imho, I think the car was particularly lacking in medium/high-speed corners and therefore they ran more wing to compensate for this which exposed them down the straight. At tracks where there were low-speed corners and short straights, teams ran with as much wing (downforce) as possible (although these kind of tracks more dependent on mechanical grip but any bit downforce helps obv) which helped neutralise McLaren’s woes. At tracks where there were reasonably long straights and many medium/high-speed corners such as Suzuka, Austin etc, that is where they struggled the most because they could not take enough of wing off, certainly not as much as their rivals could, without struggling around the corners forcing them to run with more wing to point where they were still not quick enough through the corners but also were sitting ducks on the straight.

As for their car’s certain aerodynamic characteristic that they could not replicate in the WT, teams are able to do a lot in the WT but one thing they cannot do is replicate true cornering conditions accurately via curved flow where the yaw angle relative to the flow changes locally rather than being a constant thus affecting flow structures, direction of wheel wakes etc. With this in mind, is there a possibility that this was the source of their problem(s)?

Because they need to run more wing to improve their low-speed performance, which results in less top speed. That's why they don't get punished as much in Monaco and Singapore.

[marmer]

I would be willing to bet they achieved very few overtakes on the straights before the breaking points of any track that they ran well on compared to others that could get the job done before the brakes

[Dipesh1995]

Hmm so if their weakness is low/medium-speed corners then it begs the question as to why were they quick in Singapore (best of the rest) and reasonably quick in Monaco? Imho, I think the car was particularly lacking in medium/high-speed corners and therefore they ran more wing to compensate for this which exposed them down the straight. At tracks where there were low-speed corners and short straights, teams ran with as much wing (downforce) as possible (although these kind of tracks more dependent on mechanical grip but any bit downforce helps obv) which helped neutralise McLaren’s woes. At tracks where there were reasonably long straights and many medium/high-speed corners such as Suzuka, Austin etc, that is where they struggled the most because they could not take enough of wing off, certainly not as much as their rivals could, without struggling around the corners forcing them to run with more wing to point where they were still not quick enough through the corners but also were sitting ducks on the straight.

As for their car’s certain aerodynamic characteristic that they could not replicate in the WT, teams are able to do a lot in the WT but one thing they cannot do is replicate true cornering conditions accurately via curved flow where the yaw angle relative to the flow changes locally rather than being a constant thus affecting flow structures, direction of wheel wakes etc. With this in mind, is there a possibility that this was the source of their problem(s)?

Because they need to run more wing to improve their low-speed performance, which results in less top speed. That's why they don't get punished as much in Monaco and Singapore.

That's partially my point. Every team runs more wing, typically at max angles, at tracks that are made up primarily of low-speed corners and short connecting straights such as Monaco and Singapore. This coupled with the fact these tracks are more dependent on mechanical grip neutralised McLaren's aerodynamic woes and consequently made them more competitive. The problem I believe is that McLaren were forced to run more wing on tracks made up of medium/high-speed corners and long straights such as Silverstone whilst their rivals didn't have to as much.

Take the Red Bull for example which probably has the most efficient underbody of all cars and used the same PU as the McLaren so the compromise in wing levels theoretically should have been same assuming their chassis performance were the same (which of course wasn't anywhere near the case). In Monaco and Singapore, they ran very similar levels to McLaren. In Silverstone, Red Bull ran signficantly less wing because their aerodynamic qualities allowed them to.

Monaco:



Silverstone:



In Suzuka, they attempted to run with less wing, similar to the Red Bull but with still slightly more rear wing angle which resulted in a disaster as showed by their qualifying position and the fact that they lapped nearly a second slower than their 2017 qualifying time. However, their maximum sector speeds were similar to the Red Bull (https://www.fia.com/file/73585/download?token=mxGm-8wS) showing that they couldn't carry sufficient speed through the medium/high-speed corners but were about same down the straights.

Contrary to what Boullier said in Canada about running more wing for low-speed corners, images show that McLaren ran barely any more wing angle if any compared to other teams including the Red Bull with the track being made up of low-speed corners and long straights.

[marmer]

One does need to remember though that a great deal of red bull aero performance comes from the body and the floor combined with rake
A track like Monza I am fairly sure they could do a decent job without a rear wing

[diffuser]

That clears it up then (?).

Lol. From what I can gather, the problem could be diffuser stall / loss of efficiency due to the wheel wakes leaking under the floor, especially during low to medium corners where there are larger slip angles -- high speed corners with small slip angles were apparently less effected.

At 3.55m, McLaren's wheelbase is one of the shortest^. The easiest solution: to change to a long wheelbase car that is less sensitive. I take it that it was changing to a long wheelbase car during the season was not feasible (due to the need to re-engineer the gearbox case and so on)?

^ Of course the other solution would be to retune their existing front wing, snowplough and bargeboards so the diffuser doesn't stall at large yaw angles --- but this might be asking too much!

The other issues like the outdated idea of a small airbox intake & empty space not being used efficiently under the air intake (where others have intercoolers and so on), not using the popular "double wing" style sidepod crash structures, the incorrect gear ratios -- these (while not helpful) were perhaps not the main problem.

Making the wheelbase longer just makes the wheelbase longer it doesn't fix anything. You have to have a reason/plan for using the extra wheelbase to fix the issue, otherwise it just makes the car heavier. Ferrari and Merc both used that extra space to do things in the midwing area. The Best Solution is to do what RBR did and fix it without making the wheelbase significantly longer.

[M840TR]

Motorlat is reporting that Alonso is going to be reserve driver and technical adviser for the team in 2019. He's going to be testing the Mcl34 in Barcelona during winter testing but not in any FP1s.

https://www.motorlat.com/notas/f1/8915/ ... en-en-2019

[Ground Effect]

Motorlat is reporting that Alonso is going to be reserve driver and technical adviser for the team in 2019. He's going to be testing the Mcl34 in Barcelona during winter testing but not in any FP1s.

https://www.motorlat.com/notas/f1/8915/ ... en-en-2019

Are they a reliable outlet?

[M840TR]

Motorlat is reporting that Alonso is going to be reserve driver and technical adviser for the team in 2019. He's going to be testing the Mcl34 in Barcelona during winter testing but not in any FP1s.

https://www.motorlat.com/notas/f1/8915/ ... en-en-2019

Are they a reliable outlet?

No idea.

[RonDennis]

Motorlat is reporting that Alonso is going to be reserve driver and technical adviser for the team in 2019. He's going to be testing the Mcl34 in Barcelona during winter testing but not in any FP1s.

https://www.motorlat.com/notas/f1/8915/ ... en-en-2019

Are they a reliable outlet?

No.

[ringo]

I think the failure was in transient flow analysis. This speaks to flow while cornering; ie rate of yaw vs air speed and added to that suspension movement and vibrations, wheel rotation etc.
I don't know the capabilities of the wind tunnels these days, but i highly doubt they can do all of these things to match real life accurately without tricks up the engineer's sleeves.
I can imagine a rotating platform with the car in the wind tunnel, high speed cameras, steering rack movements, spinning wheels on the model and suspension movement would all need to be combined to simulate close enough, and this is on a scaled model. It's not easy at all. I could understand if they messed up.

For the high speed corners, big radius, flat etc., the car has more gentle transients akin to the traditional wind tunnel setup.