hi all,
i was thinking about this the other day and i couldn't answer myself. my first question is about the double deck diffuser: i was looking at older pics of f1 cars from 2003,4 and before this year, they look totally different. but i think that they also looked different than the single diffuser cars at the start of this year..can someone explain the issue here for me? they did cars back then have single diffuser, or was it different?

second question: i read a few weeks ago that martin witmarsh said he is baffled why ferrari is focusing on next year completely, according to him, developing the 09 would help designing the 2010 car that's why maybe mclaren is still developing 09 AND 2010 whereas Ferrari are 100% focusing on 2010, can someone shed the light on this issue? coz im not sure if the cars will look completely different to this year..

question 3: since there was a budget cap or restriction for this year, how did that affect the teams? i saw the 08 budgets, is there a way to get the 09 budgets for f1 teams?

edit: found this
http://www.f1network.net/boards/read/s491.htm?936,10565609
according to this, the teams are still spending wayyy to much..??

thank you for the help. enjoy !

I don't know about your first question. What I do know is that you seem to have your years mixed up. It's 09 right now, and 2010 is next year.

Now for your second question. I have been saying this for a couple of months. The only thing I can come up with is that since with the refueling ban, and the fact that even Ferrari admits the F60 isn't all that great, that they are starting over from scratch, so any bits they put on the car now, may not translate over to the new car.

Third, there was no budget cap.

hellaciouss_craw - 21 October 2009 12:20 PM

I don't know about your first question. What I do know is that you seem to have your years mixed up. It's 09 right now, and 2010 is next year.
Now for your second question. I have been saying this for a couple of months. The only thing I can come up with is that since with the refueling ban, and the fact that even Ferrari admits the F60 isn't all that great, that they are starting over from scratch, so any bits they put on the car now, may not translate over to the new car.

Third, there was no budget cap.

thnx for your remark, i fixed it. ok but regarding the 09 budgets, i know there is no cap but they said there are restrictions so teams will not spend like 08 and then there will be more restrictions for 2010 and 2011 in order to achieve the spending level of early 1990's. what im saying, since i "know how much the teams spent last year (according to articles), can i know how much they spent this year?

Regarding #3 – cost reduction in F1 is very complex. The current engine freeze is 100% to address this, and is but one means to address the problem. Another means, a budget cap, was approached by the FIA during the 2009 Concorde agreement negotiations, and was to be put forth somehow in that unpublished doc and the 2010 sporting regs – but they did not – per hellaciouss_craw.^

However, the FIA backed away from cost cap regulation under the notion that proposed self regulation would prevail. Kind of like the US movie industry (among others) convincing the US Government they will regulate themselves and do not need governmental interference. I guess we are somehow to be assured by the bold part below.

http://www.fia.com/en-GB/mediacentre/pressreleases/f1releases/2009/Pages/2010_f1_regs.aspx
”The basis for the FIA agreeing to drop plans for a cost cap was the proposal prepared by the Williams team over the Silverstone weekend which would allow an agreed reduction of expenditure to the level of the early 1990s by the end of 2011 to be dealt with by the teams themselves. This reduction was agreed by FOTA and confirmed by them in Paris on 24 June. This would be a private, legally-enforceable contract involving all the teams, but not the FIA. The FIA confirmed in Paris that once this agreement is in place, the cost cap provisions can be removed from the 2010 Sporting Regulations.”

I can see why the FIA wants to stay away from cost caps – because they are not enforceable, so I don’t see how self imposed caps will work either. I really like how the FIA leverages as much as possible onto FOTA though – then if it does not work – FIA then has the support (to backup their existing authority) to put forth controls of a different type.

Note that freezing engines does not preclude spending money on engine development, which can be applied the next time they are unfrozen. The key is to change the engine spec to a new and unknown configuration, such that current monies spent would be for naught. So it’s not just freezing design – it’s freezing with an unknown future spec eminent.

Regarding #2 – we are told by Ferrari they have been working (development team) solely on 2010 parts. This may be a bluff, to soften the 09 competition. Or … I’d like to think that $5M for 3rd place is a pittance compared to the beautiful unholy quest for championship wins. Brawn proves this in spades, as they cut bait early last year.

Regarding #1 – I don’t now anything about it (and little on #2 and #3 for that matter), but we do have this beautiful shot of a DD (vs. the Toyota Triple Diffuser). I’m fascinated by the asymmetric aspect of it.



This sites talks a bit about the different types of diffuser solutions (beautiful subterfuge). Hooray for the smarter designers!

I like Newey’s quote here.

"There’s no such thing as the spirit of the regulations, luckily!"

danidanilian - 21 October 2009 12:03 PM

hi all,
i was thinking about this the other day and i couldn't answer myself. my first question is about the double deck diffuser: i was looking at older pics of f1 cars from 2003,4 and before this year, they look totally different. but i think that they also looked different than the single diffuser cars at the start of this year..can someone explain the issue here for me? they did cars back then have single diffuser, or was it different?

second question: i read a few weeks ago that martin witmarsh said he is baffled why ferrari is focusing on next year completely, according to him, developing the 09 would help designing the 2010 car that's why maybe mclaren is still developing 09 AND 2010 whereas Ferrari are 100% focusing on 2010, can someone shed the light on this issue? coz im not sure if the cars will look completely different to this year..

question 3: since there was a budget cap or restriction for this year, how did that affect the teams? i saw the 08 budgets, is there a way to get the 09 budgets for f1 teams?

edit: found this
http://www.f1network.net/boards/read/s491.htm?936,10565609
according to this, the teams are still spending wayyy to much..??

thank you for the help. enjoy !

Taking your questions more or less in reverse order...

3. The budget cap may have hindered the top teams like Ferrari a little; they didn't spend as much on luxury, frivolities and maybe a touch less wind tunnel and computer simuilation time as before. Beyond that, they didn't really suffer.

Smaller teams, like Brawn and Red Bull did much better this season, since they didn't have to compete with teams that out-spent them by three or four to one. The cap also brought back a little of the old "designed by eye," seat-of-the-pants designing that was common 40 and 50 years ago.

2. Ipso said it well: "we are told by Ferrari they have been working (development team) solely on 2010 parts." Sometimes, a team knows their cars just aren't competitive, so rather than bang their heads against the wall trying to improve them, they soldier along with what they've got while desiging something that works well with next year's rules, so they have time to develop it. There's also a bit of creative rule bending here, because they're testing features for "next year's cars" on "this year's cars," which they've already given up on.

Now for Question One, which takes awhile to explain, so bear with me, especially if wordy-old-me runs over into the next post.

First, you need to know how a diffuser works.

As a car moves through the air, it forces some of the air downward, compressing it under the bottom. This speeds up its veolcity, which reduces air pressure, according to Bernouli's formula, as shown in this illustration from Racecar Engineering magazine.



Figure 1. airflow through a diffuser.


Next, having compressed the bottom layer of air, the trick is to re-expand it, smoothly and carefully. Done properly, this will reduce the volume the air can flow through, but not increas the amount of air, which also reduces pressure; or creates a partial vacuum, depending on how you look at it. Either way, when you take a 2.36 inch (6cm) layer of air and allow it to expand to, say, twelve inches, you still have the same number of air molecules, but now they're in a much larger space. The result is lower pressure. Figure 1 shows the general flow pattern, where the closer the lines are together, the greater the veolcity and the farther they are apart, the greater the volume the same amount of air can fill. Figure 2 shows how the air expands in the diffuser (again, note the little arrows separating), versus how fast the air is moving. (Brighter colours mean faster air)



Figure 2. Side view of diffuser air flow.

Figure 3. Velocity vs. volume in a diffuser.



And in Figure 3, we see a view of the underside of the diffuser, with high speed air in blue and high volume/low pressure air in shades of green and yellow.

The vanes you see in the bottom of the diffuser are there to smooth out the airflow, keeping it straight, rather than becoming turbulent.

Now that we've established that, let us consider the differences in diffusers.

Years ago, diffusers were an outgrowth of the original "venturi" side pods on "ground effects" cars of the late 70s and early 80s. (See Figure 4.)



Figure 4. Lotus 79 underbody, showing venturi tunnels.


In the "Ground Effects" era, the whole sides of the car, for five feet or more, was a giant venturi tunnel, operating on the compression-velocity/expansion-vacuum principle. The result was something like two tons of downforce, which was considerably more than the cars weighed.

Eventually, these tunnels became so powerful -- and the methods of sealing them against high pressure air leakage so outlandish -- that the FIA said, "ENOUGH!" and limited "venturi effect tunnels" to the area between the front edge of the rear wheel and the trailing edge of the rear wing. (pause for a moment for the next post.)

Now for the difference between diffuser types.

The FIA's early flat-bottom-plus-diffuser cars had relatively large diffusers. They were quite long and ran most of the width of the chassis. At one point, cars even had their exhausts routed into the diffuser tunnels to speed up the airflow and add a touch more gas to the mix. And with considerable downforce.

Even this got to be too much, so the Overtaking Working Group came up with a new idea. They reduced the size of the diffusers still further, and described their limits as "boxes" that could be any shape, provided they were no bigger, over all, than the maximum limits. Figure 5. gives you what they had in mind.



Figure 5. FIA "boxes" for diffusers.


The idea here was to allow some creativity, but still keep things in check. Some teams, such as Ferrari and McLaren, took this "box" concept at face value, along with the FIA's mandate that there could be no gaps in the diffuser that would allow more airflow. That gave rise to Ferrari's first diffuser, seen in Figure 6.



Figure 6. Ferrari's first diffuser


Notice how that cross section looks rather like the FIA's "diffuser box," with relatively little finnagling. It's just a curved underbody with some strakes in it to prevent turbulence. NOte the lack of ductwork for the "double diffuser" evident in the Brawn and Williams diffusers. McLaren's first diffuser was very much the same. If all the teams read the rules this way, they'd all have come up with similar diffusers. However...

The folks at Brawn read the rules differently. First, they noticed that nothing was said about holes in the underbody -- or elsewhere -- that let the rub blocks protrude through the underside. Or air flowing over the underbody, specifically over the side pods and the separator plates, etc.

Now let us consider something called the "slot effect."

If you've ever sailed a boat with a mainsail and a jib, you probably already know about this. When airflow is diverted by one airfoil (the jib) and made to flow over a second (the maisail), it increases the speed of airflow over the main, resulting in higher velocity, lower pressure (the Bernouli effect again), and thus more lift. Or downforce. Figure 7. shows how this works.



Figure 7, airflow through the "slot effect.

Here again, note how the jib affects the mainsail's performance. Since nothing happens in isolation on a boat or in a race car, carefully channeling the airflow above and around the diffuser can help it work better. That's one reason why Formula One rear wings are so relatively tiny and flat: They aren't just producing downforce, themselves, they are also controlling airflow around the diffuser.

Now let's look at Figure 8. which is a diagram of a double diffuser.



Figure 8. Airflow through single diffuser (above) and double diffuser, below. N


Now here's where things get clever and the rules get bent: The Brawn folks looked at the rules and noted that while they did not allow holes in the diffuser, itself, they said nothing about ducting air around other parts of the underbody, like, say, the rub blocks. They took this to mean that, for "smooth airflow," they could put ducts that took air around the rub blocks and sent it out above the diffuser body, itself. Figure 9 shows how this works.



Figure 9A. Airflow through a "single" diffuser.

Figure 9B. Airflow through the channels in a double diffuser. (The separation between the main diffuser and the "double diffuser" ductwork is not shown, other than the end of the man diffuser, whish is a red line below the red arrows.)




Alright, you say, so now you've got air flowing over and under the diffuser underbody panel. So what?

Here's what: Remember the "slot effect?" And the fact that nothing happens in isolation in a Formula One car? And the interaction of the diffusers and the lower rear wings of 2008 and earlier? Now let's put this all together.

What happens in a "double diffuser" is this: The air scooped up from the forward-facing ducts, over the sidepods and elsewhere, is kept in its high-speed/low volume mode and not allowed to diffuse. Thus, it is moving with considerable velocity when it comes to the end of the ductwork above the main diffuser.

As this high speed air passes out the back of the tunnel, it combines with the slower, higher-volume-box air in the diffuser and works like the venturi effect of a spray gun. It draws the relatively low-velocity air in the diffuser along with it, at higher speed. That increases the speed of the expanded air, which generates still lower pressure.

Thus, we have a version of the "slot effect," where faster air moving seprattely from the diffuser increases the velocity of the air flowing through it, and in the process, increases its efficiency.

Figure 10 gives you a look at how this "double duct work" was finnagled.



Compare the actual underside of the Red Bull car with this drawing showing airflow from the gap around the rub blocks and the air exiting that ductwork above the diffuser plate.
In the Red Bull car's case, the air exits through broad, shallow slots, as on the Williams, which has a similar configuration. In the Brawn, it's a wider V-shaped opening.


Clever, eh!

Ipso, I was referring to the FIA cap. This, "agreement" by FOTA to reduce costs just has a funny smell to me. Like you said, how do you regulate something like that? We've seen first hand this year how well those agreements work.

Thanx for the info GreyWolf, in ten minutes I learned more about the diffusers from you than Matchett has managed to teach me over the course of the season.

woooww..thank you greywolf for the info !!!!!! are u an engineer or something???? thnx again..i learned a lot about the diffuser issue, apparently, it is a big deal ! i man i always like to learn technical stuff about f1 and this was really interesting.

on another note, do u guys think the number for the f1 budgets mentioned in the link i posted make sense? if yes, then the stupid cost reductions didnt work because the teams spent the same in 2008.

Grey,
Nice job, though consider that the second sail description isn't exactly the reason for the second tier of the diffuser.
Reverting back to the sail description, ducting two small volume ducts in a high volume area (as in the Brawn and Red Bull design) Would they perform as you say, like a split wing effect or main/secondary sail.
Or is the high volume area a vortex generator? To replace the vortices that were present below the PREVIOUS rear wing (too far away in 09) location that effected the extraction of air out of the diffuser?
Notice that the Red Bull photo that the ducting is picking up air in location that is in the right angle location of the floor. This is a vortex induced airflow area (meaning increased high pressure due to the right angles) and is ducted into a higher volume box (slowing airspeed) and the box is shaped in a venturi fashion (inside) and the extraction point is also shaped in a vortex generation shape.
It's not rocket science to conclude that the second tier on the Brawn, Red Bull and Mclaren (the largest example of it) is a massive vortex generator to effect extraction of the diffuser below, which the low slung rear wing of yesterday's rules, was helping the diffuser.
BTW, the interior slats inside the diffuser, also create counter rotating vortices out the back of the diffuser, also aiding in extraction of the volume of air inside it. IMHO.
Excellent explanation and presentation otherwise...

GreyWolf74 - that was great! Thank you for taking the time to present that info. Outstanding work! (As my friends would say “takin’ it to the next level!”)

Speedsense – vortex generation – interesting. But does not the vortex effect simply control consistency of airflow, which is a vital role, but a secondary role, more like the sprinkle on a pool for divers – to allow them clean entry. It’s primary role in aeronautics is to provide consistent airflow across the flight controls, not to significantly increase wing lift – no? The wikipedia entry for Vortex Generator talks about “re-energizing the boundary layer” by bringing “rapidly-moving air from outside the slow-moving boundary layer into contact with the aircraft skin” (i.e. induced turbulence – a vortex) How is that possible if the vertical ducts are pressure distinct, and the air does not touch until exit?, which seems to be the case in the vertical dimension. Seems like the vortex function is served by the side baffling and such (red arrow below – and various vertical baffles) whereas GrayWolf74’s slot-effect are the blue arrows – the primary purpose of the multi-level diffuser.

http://www.formula1.com/news/technical/2009/821/642.html

Actually – it looks like both slot-effect and vortex generation can happen in both the vertical and horizontal dimensions as you look across the various baffles that horn out in all directions – in a crazy harmonic mix of downforceness – like a Bach pipe organ fugue.

Ahhh… Bach!


http://www.racecar-engineering.com/articles/f1/313897/diffusers-they-are-legal.html

The section of regulation in dispute reads as follows.

3.12.7 : No bodywork which is visible from beneath the car and which lies between the rear wheel centre line and a point 350mm rearward of it may be more than 175mm above the reference plane.

Now if one directly relates this section to the apparent apperance of the Williams, Toyota and Brawn diffusers, they are all legal! As long as the second upper elements of the diffuser are not visible from below the car at any point from the wheel centre line-350mm to the rear. Thus they are not constrained by the regulation stipulating a miniumum height of 175mm.

How far this dispute will continue depends on a number of factors. If the FIA stewards clear the cars at scrutineering it is almost certain a team will lodge a formal protest after the race. If this is the case whoever is the losing party will no doubt appeal requiring an apperance in front of the FIA Court of appeal. If, as we believe, the designs are legal they could still be outlawed due to not complying with the intended meaning of the regulations.

ipso - 22 October 2009 03:28 AM

GreyWolf74 - that was great! Thank you for taking the time to present that info. Outstanding work! (As my friends would say “takin’ it to the next level!”)

Speedsense – vortex generation – interesting. But does not the vortex effect simply control consistency of airflow, which is a vital role, but a secondary role, more like the sprinkle on a pool for divers – to allow them clean entry. It’s primary role in aeronautics is to provide consistent airflow across the flight controls, not to significantly increase wing lift – no? The wikipedia entry for Vortex Generator talks about “re-energizing the boundary layer” by bringing “rapidly-moving air from outside the slow-moving boundary layer into contact with the aircraft skin” (i.e. induced turbulence – a vortex) How is that possible if the vertical ducts are pressure distinct, and the air does not touch until exit?, which seems to be the case in the vertical dimension. Seems like the vortex function is served by the side baffling and such (red arrow below – and various vertical baffles) whereas GrayWolf74’s slot-effect are the blue arrows – the primary purpose of the multi-level diffuser.

http://www.formula1.com/news/technical/2009/821/642.html

Actually – it looks like both slot-effect and vortex generation can happen in both the vertical and horizontal dimensions as you look across the various baffles that horn out in all directions – in a crazy harmonic mix of downforceness – like a Bach pipe organ fugue.

Ahhh… Bach!


http://www.racecar-engineering.com/articles/f1/313897/diffusers-they-are-legal.html

The section of regulation in dispute reads as follows.

3.12.7 : No bodywork which is visible from beneath the car and which lies between the rear wheel centre line and a point 350mm rearward of it may be more than 175mm above the reference plane.

Now if one directly relates this section to the apparent apperance of the Williams, Toyota and Brawn diffusers, they are all legal! As long as the second upper elements of the diffuser are not visible from below the car at any point from the wheel centre line-350mm to the rear. Thus they are not constrained by the regulation stipulating a miniumum height of 175mm.

How far this dispute will continue depends on a number of factors. If the FIA stewards clear the cars at scrutineering it is almost certain a team will lodge a formal protest after the race. If this is the case whoever is the losing party will no doubt appeal requiring an apperance in front of the FIA Court of appeal. If, as we believe, the designs are legal they could still be outlawed due to not complying with the intended meaning of the regulations.

An open "duct" with air flowing through it, with small radius corners, will create four counter rotating vortices out the back of it. This is the first clue.
The same open duct with a 2" radius in the corners, will create no vortices or very small insignificant vortices.
Second clue as to the ducting being used by these cars, and why.
A carefully placed and controlled location of a vortex, can lessen a separation point of the bottom of a wing and make a wing more efficient. It is the rotation direction, size and strength of the vortex that is of importance to it's function.
All of the arrows, in both diagrams have vortices streaming out the back of the diffuser behind them. There are many more being created by each 90 degree angle surface (the interior strakes) AND all of the "lips" or gurney-like flip ups contained on the upper surfaces.
The occurance of these vortices is of an engineered design and their creation is completely on purpose for effect.
A perfect example of the use of vortex generation can be found when ground strakes on ground effect tunnels were outlawed and an air gap was created from the side pod to the ground. Vortices were used to "help" replace the sealing effect of the strakes and prevent intervention from outside air streams as well as escaping air streams from within.

With diffusers, there are vortex generators before, on the sides, on top and trailing edges in attempt to "seal" the air flow to the ground. (the highest degree of the effect, is sealing the sides of the diffuser to the ground, illegal by rules).

A few rules of the road (pun intended), as applied to diffusers:

A)they do not work as a upside down wing
B) they do not work as a Diffuser (in the sense that they would in a windtunnel). They are a diffuser by name only.
C)They do not "create" downforce, but rather remove high pressure areas that create lift in the floor, so that the wings can create higher downforce. (this can be easily seen by removing the wings on a car, and keeping the diffuser. Then replacing the wings and removing the diffuser and recording the results all in a windtunnel.
The downforce numbers are significant when the two (wings and diffuser) are used in tandem and very insignificant if only the diffuser is used. The downward force numbers of diffuser pale against the downforce numbers of a wing and the further from the ground you move the diffusers, the closer to 0 the numbers become. ***Not true with a wing***
You can relate the vortex generation to how it's used on an airplane to race car thinking, though to do so, you will need to invert the plane and put the wings boundary layer within reach of the ground at take off speed.
And yes, the vortex is a secondary element in design, but one that can increase the diffusers performance as result of careful placement of these..