Technical challenge! A3 paper sized diffuser hole!

[bonjon1979]

With all this talk of A3 paper sized diffuser holes for the toyota and possibly the Ferrari B-spec car (which may not actually exist...) can anyone draw a simple drawing of how this solution could work? We all seem to be experts at analysing the cars once they've been made but can anyone dream up a way this fabled idea could work?

(No I'm not secretly Vijay trying to get some development for free! Just interested to see what people can come up with.)

[JohnsonEvilTwin]

It will look like a diffuser with a BIG A3 sized hole in it!

By the way, why are Ferrari threatening action on anyone who takes the diffuser law to the extreme? Could it be they have missed a trick AGAIN?
I really am tired of this notion that ferrari have a birthright to win or have the fastest car.

[bonjon1979]

Yeah, I was kind of wondering how it could actually work. Because from below it needs to look like one continuous piece I'm guessing there has to be some kind of double floor with one section suspended above a large gaping hole (like a suspended ceiling) so that from below it looks like one continuous floor.

[JohnsonsEvilTwin]

From my rudimentery understanding of aero laws, the diffuser is there to allow greater downforce by forcing the air through channels. Now the bigger the channel, the greater the amount of air that will flow through it. However there needs to be a plane or "aero device" that is efficient enough to be able to convert the larger air flow into "downforce".

You see a designer has no interest in knowing what happens to the air 1mm after it has left the diffuser. Only that the car is flowing through it as smoothly as it can while creating as much downforceas it can doing so.
Now the "A3 Hole" will no doubt have a huge cavity within the diffuser, but what will be interesting is not the hole itself, but the bits and bobs around it that make said hole work!

I hear rumblings across the interweb of a huge Mercedes GP/McLaren/Red Bull diffuser yet to see light of day, yet they do exist with every intention of being used BY DESIGN. Ferrari seem to be aware that they are behind if these "super diffusers" are unleashed at Bahrain, hence the squirming noises eminanting from Maranello(not for the first time)

[PlatinumZealot]

Hoooooold ON! Evil twin...

You should read the diffuser thread.. somethings you said were not entirely correct.

Anyway.. all it was saying is that the flow cross section of some part of the diffuser is of similar area to that of an A3 sized paper.. which is really Two A4 (A4 is close letter size) papers.

A3 area is:

29.7cm x 42.0cm = 1247.4 cm^2


The exit of a regulation single diffuser is :

17.5cm x 100cm = 1750 cm ^2

The rumour did not say where on the diffuser (exit entrance, upper or lower) is A3 size cross section but we can deduct this A3 size is the exit of the 2nd diffuser since it is smaller than 1750cm^2.

It Roughly 70% of the main diffuser. I have no Idea how much down-force this brings because the diffuser is not just about the size. Also I think it would be even more interesting if we knew the size of the 2nd diffusers from last year. I am pretty sure there weren't 70% just by looking on them. All I can say is that 70% is HUUUUUGE!! Maybe the Maclaren MP4-25's might be around that size..

[Richard]

Yes the exit of the McL is of that order. But as we found last year, the DDD also needs an upstream supply, and a downstream wake to draw the air out of the DDD exit.


A smaller effective duffuser is better than a big one that doesn't work.

I want to see what the new floors are like, that's crux point, all that air has to be supplied by holes in the step ....

[BreezyRacer]

The key to this year's diffusers will NOT be the exit size, it will be the inlet configurations in the under tray. Sigh .. more stuff we cannot see ..

[Edis]

From my rudimentery understanding of aero laws, the diffuser is there to allow greater downforce by forcing the air through channels. Now the bigger the channel, the greater the amount of air that will flow through it. However there needs to be a plane or "aero device" that is efficient enough to be able to convert the larger air flow into "downforce".

You see a designer has no interest in knowing what happens to the air 1mm after it has left the diffuser. Only that the car is flowing through it as smoothly as it can while creating as much downforceas it can doing so.
Now the "A3 Hole" will no doubt have a huge cavity within the diffuser, but what will be interesting is not the hole itself, but the bits and bobs around it that make said hole work!

I hear rumblings across the interweb of a huge Mercedes GP/McLaren/Red Bull diffuser yet to see light of day, yet they do exist with every intention of being used BY DESIGN. Ferrari seem to be aware that they are behind if these "super diffusers" are unleashed at Bahrain, hence the squirming noises eminanting from Maranello(not for the first time)

The purpose of a diffuser is pressure recovery. It converts the kinetic energy of the high velocity low static pressure air to high static pressure low velocity air. With a greater pressure recovery the air pressure under the car will decrease and there will be a greater pressure difference over the car which will result in more downforce.

[JohnsonsEvilTwin]

Edis


You are correct when you say its about pressure.
I used a very basic description based on what the air does when it has reached the diffuser. I have read a few articles on here and WIKI that say the whole car is now designed to get the air to the diffuser as cleanly as possible to create a higher pressure on the back end of the car. This pressure creates better grip for the tyres and allows the car to travel faster when cornering.

I admit when it comes to the pressure side of things I hesitant as i know nothing about it, suffice to say there is a ying yang of high and low pressure going on at the back of the car.
The larger hole will undoubtedly add higher pressure. MUCH HIGHER PRESSURE.

Its a reason as to why Mercedes and a few others are not running their definative 2010 aero package. They are leaving it to the last possible moment to test them, so as to shorten the lead time rivals have to copy the design "a la double diffuser".
Be good to actually see from graphics how the airflow is manipulated from the front of the car all the way to the back.....watch this space!

[Richard]

The larger hole will undoubtedly add higher pressure. MUCH HIGHER PRESSURE

No

Too big and it will stall. The upstream supply and down stream flow have to be balanced.