McLaren MP4-28 Mercedes

[JimClarkFan]

Simple... the AoA of the start of it is too steep, and the air detaches... why is that hard to understand?

And we know this is the problem in the case of Mclaren how?

Remember not all of us took physics further than GCSE!

[henra]

I assume it caused by a stall in the airflow which prevents clean air for passing underneath, but how does that happen in the first place?

Ususally that happens when the adverse pressure gradient at the top of the diffuser is too steep.
Either they simply designed the diffuser too agressive (read steep) or they have trouble getting enough velocity of the air flowing over the upperside of the diffuser.
The higher nose compared to last year will probably increase somewhat the mass flow underneath the floor, which could also contribute to the problem to some extent.

[JimClarkFan]

I assume it caused by a stall in the airflow which prevents clean air for passing underneath, but how does that happen in the first place?

Ususally that happens when the adverse pressure gradient at the top of the diffuser is too steep.
Either they simply designed the diffuser too agressive (read steep) or they have trouble getting enough velocity of the air flowing over the upperside of the diffuser.
The higher nose compared to last year will probably increase somewhat the mass flow underneath the floor, which could also contribute to the problem to some extent.

Thanks henra

[McG]

How does Mark Hughes know this?

[Pup]

Well, I didn't tell him. Let's clear that up right now.

[shelly]

From omnicorse again:

http://www.omnicorse.it/magazine/26083/ ... lla-mp4-28

they say mclaren is preparing for an heavy upgrade of the rear of the car to solve their aero problems. Currently they have good performance at low ride heights they cannot sustain all race long because of plank wear.

[Pup]

If they show up in China with an extra one and a half seconds in their pockets, I'll be a happy pup. Still no confirmation of where the aero is going wrong, though.

[gary123]

From omnicorse again:

http://www.omnicorse.it/magazine/26083/ ... lla-mp4-28

they say mclaren is preparing for an heavy upgrade of the rear of the car to solve their aero problems. Currently they have good performance at low ride heights they cannot sustain all race long because of plank wear.

they say that the problem of the car is the rear end! the exhaust systems dosent works according to omnicorse,and the mclaren will bring to china e new rear end,newsospensions geometry and maybe a new gearbox for the sopensions.
and seems that the pull rod creates only setup problems and they run whit a stif setup sospensions.this makes the car very sensitive to height change and creates a problems.

[ringo]

From omnicorse again:

http://www.omnicorse.it/magazine/26083/ ... lla-mp4-28

they say mclaren is preparing for an heavy upgrade of the rear of the car to solve their aero problems. Currently they have good performance at low ride heights they cannot sustain all race long because of plank wear.

Shows how much they depend on their dream world simulator to build the car.
Haven't prepared for real life problems, they just built blindly with their perfect world developments.
If only the car could ride as low as they expected it would probably be very good.
And the fact the suspension has so much antidive we can infact see they were aiming at extremely low ride height with small body movements to prevent floor stalling and plank wear.

[JimClarkFan]

If they show up in China with an extra one and a half seconds in their pockets, I'll be a happy pup. Still no confirmation of where the aero is going wrong, though.

Any kind of improvement and I will be a happy 'pup' too

An improvement of 2 seconds is what I am looking for though .

Unlikely admittedly, but there should be big potential with this car, despite the unbelievable cock up this early in the season.

[gixxer_drew]

I think a lot of people in this thread don't give them enough credit. We arent talking about high school design an F1 car project. These are smart guys, surely.

From omnicorse again:

http://www.omnicorse.it/magazine/26083/ ... lla-mp4-28

they say mclaren is preparing for an heavy upgrade of the rear of the car to solve their aero problems. Currently they have good performance at low ride heights they cannot sustain all race long because of plank wear.

From Shelly's link, IMO pitch sensitivity can be a nasty bit because of course you do the pitch/ride/etc stuff in the tunnel but you get the data on what attitudes to test from the vehicle dynamics guys who are often working concurrently. You cannot possibly afford to test every iteration at every attitude anyway. VD group can simulate but may not even have a tight handle on the attitude range you need to design for until the car is being tested in the real world... which for F1 is basically not until season started. Even laser scanning the surface has its limitations. If their new suspension setup is designed around aero ride heights (as Button was saying in that interview), they may have even expected initial troubles and making a long term play for a better suspension setup. I can also see why for political reasons it makes sense to play it a certain way to the media. A front aero problem is a rear aero problem and vise versa. Changing the front to get more flow to the rear is going to take more time to develop than milking more downforce out of the rear. Especially if you are willing to throw out drag and try and fix that over the rest of the season. Which is exactly what I would do considering the current regs. My$.02

[JimClarkFan]

I think a lot of people in this thread don't give them enough credit. We arent talking about high school design an F1 car project. These are smart guys, surely.

From omnicorse again:

http://www.omnicorse.it/magazine/26083/ ... lla-mp4-28

they say mclaren is preparing for an heavy upgrade of the rear of the car to solve their aero problems. Currently they have good performance at low ride heights they cannot sustain all race long because of plank wear.

With the absence of out of season testing, it would seem that playing it conservative side is the best approach these days. Macca fell into the same trap they have fell into in previous years... by doing too much they had to play catch up at the start of the season.

Ferrari got a lot of stick for this last year, but Mclaren has done this, to varying degrees 3 (well, certainly 2) of the last 4 years.

[gixxer_drew]

I think a lot of people in this thread don't give them enough credit. We arent talking about high school design an F1 car project. These are smart guys, surely.

From omnicorse again:

http://www.omnicorse.it/magazine/26083/ ... lla-mp4-28

they say mclaren is preparing for an heavy upgrade of the rear of the car to solve their aero problems. Currently they have good performance at low ride heights they cannot sustain all race long because of plank wear.

With the absence of out of season testing, it would seem that playing it conservative side is the best approach these days. Macca fell into the same trap they have fell into in previous years... by doing too much they had to play catch up at the start of the season.

Ferrari got a lot of stick for this last year, but Mclaren has done this, to varying degrees 3 (well, certainly 2) of the last 4 years.

Maybe so, the tire thing is probably the biggest threat to the engineers having a clue what is coming for them next.

[Kiril Varbanov]

I may have misread the last two pages, but as far as I can see it, someone was suggesting that MP4-28 is running a steep angle on the kick line of the trailing edge of the diffuser?
Usually, every time when you do something, you gotta ask yourself: Why? I'm in no doubt that Mclaren aero people are aware that such sharp condition shape change would cause the usual adverse pressure gradient and will subsequently lead to airflow detachment (in theory).

Since the diffuser itself is a relatively drag-free way to generate some nice amounts of downforce, I can't see why would you do something like that (again, in theory). On a related note: is there a picture of their underside? I suspect that they might want to use what's allowed by the rules - one of my old articles describing this in details.

[Gridlock]

Macca fell into the same trap they have fell into in previous years... by doing too much they had to play catch up at the start of the season.

Ferrari got a lot of stick for this last year, but Mclaren has done this, to varying degrees 3 (well, certainly 2) of the last 4 years.

They've also repeatedly acknowledged that they're taking some of the 2014 pain now (pull-rod, specifically) and were surprised that rivals didn't also (Red Bull and Mercedes, I'd say). And look at who's in front in 2013..