The battle of flexing rear wings

[Reca]

Just robbed this from another forum

The controversey with Ferrari's rear wing is that there is no "spacer" between the top and bottom rear wing. So down the straights under load, 2 wing peices become one creating less drag by restricting airflow between the winglets.


watch the gap. ==>[IMG:305:92]http://img417.imageshack.us/img417/8229 ... 4ah4ce.gif[/img]

Does this flap move ?

[IMG:686:290]http://img386.imageshack.us/img386/8589 ... ing1fy.gif[/img][/URL]

[dumrick]

No. Light source has moved. Right?

This is starting to annoy me, really. I'm no Ferrari fan, and I supported the front wing element controversy. By now, the front wing has been modified, we all now that every material flexes, that Ferrari's rear wing passes scrutineering and that working in how the RW flexes (within the rules) can give teams an advantage. So, if Ferrari has this better studied than other teams, my congratulations, it's time for the others to start working hard on it.

And if there's a shade of a security problem, it's up to the FIA to change the rules.

[saam]

Most people would much rather have a big lump in their throat than to admit Ferrari are taking care of business.......

[Reca]

No. Light source has moved. Right?

Damn, you got me But that one was easy, try with this one :
[IMG:516:219]http://img364.imageshack.us/img364/2576 ... ng24yi.gif[/img]

As for the safety issue, I heard it repeated in many places that flexing wing aren’t safe, but I really don’t get where the problem is. A car with a flexing wing is still required to reach end of the race to get points, right ?
If the wing, just like any other part of the car for that matter, breaks, the car stops and it’s goodbye wins and points. Since the only reason these guys spend 24/7 designing a f1 car is to win a champ, and to win a champ you need to obtain more points than your opponents, you can bet these guys spend a quite considerable amount of that time making structural calculations/testing to avoid rupture of the wing. That’s independent by the fact that the wing is designed to flex or not, and even before being important for driver’s safety, it’s fundamental for the main aim of the competition.

FIA has to introduce and enforce rules on car ability to cope with a crash because team designers wouldn’t take the necessary measures otherwise; the way a car copes with a crash doesn’t make difference for the race result so it’s not an important aspect for the designer, it becomes important in the moment FIA tells you that if the car doesn’t pass crash tests you can’t race.
The necessity to keep the car in one piece and reach the end of the race on the contrary is something teams are very interested in so they already do whatever it takes to guarantee the wing doesn’t fail.

If the concept that a part deforming in a programmed way during the race is unsafe, well before talk about wing we should talk about tyres, these are lot more unsafe because the structural characteristics are lot more difficult to analyse/model and are influenced by lot more variables than the reasonably predictable behaviour of a flexing carbon wing.
Also, going by memory here, I remember far more incidents caused by tyre issues than incidents caused by wing failure, and flexing wings are commonly used since a few years now.

[mini696]

Thats just the lightsource moving again, plus the suspension is loaded up giveing an optical illusion that the wing has moved down.

[RH1300S]

I've got a question, I hope some of you aero guys can answer this.......

It has been reported many times that closing the gap between the wing elements reduces drag; I have been accpeting this without question.

However, I recall reading a book some while back that explains why muliti-element wings arrived. The theory then was that, instead of dragging a big banana shaped (section) barn door behind the car, using multiple elements the angle of attack of the whole wing could be increased with much less drag penalty (or was it risk of stalling?).

So, how does closing the gap reduce drag?

If the wing flexes back and reduces the angle of attack I can see how it reduces drag and downforce - but just the gap????

Thanks

[scarbs]

Slot gaps are there to maintain attached flow under the wing at high angles of attack. This maintains downforce with a small cost in drag.
However if the slot gap closes, then the wing stalls, downforce is reduced and so is drag.

In some respects the teams are using a wing that is failing aerodynamically at high speed, an odd situation.

[kilcoo316]

So, how does closing the gap reduce drag?

Yeah, this had me for a while, as I was thinking along conventional aircraft lines... and angles of attack. I'll try to explain it, but this could be a little messy

Usually, you consider a wing produces two forces, lift and drag, and these are at 90 degrees to each other. The lift comes from the pressure distribution around the wing (and has an upward component of something like cos(5) degrees [the pressure force won't be exactly vertical usually], and the drag from skin friction/boundary layer growth and sin(5).

The 2nd element in an F1 rear wing is at a massive AoA, if the wing is operating with 100% attached flow, the 'lift' force has a very large component in the horizontal plane - the downforce component from pressure forces may only be cos(70) while the drag component is sin(70).

Stalling the 2nd element will reduce the pressure force (from the wing operating normally), and replace it with detached flow and base pressure drag. As the teams are finding an advantage, I must assume the detached flow generates less drag than the wing operating normally.

[scarbs]

Willem Toet explained it to me, so theres clearly an advantage.

[kilcoo316]

Willem Toet explained it to me, so theres clearly an advantage.

I was gonna run a few CFD sims to see what kind of advantages it would be, but since I'm a lazy bollocks, I never got round to it

[RH1300S]

Thanks, both of you. That is an explanation I can accept as believable. You lose efficiency, but because you have stalled the wing, drag drops.

So, we should assume that someone has very carefully worked out the speed at which loss of potential cornering force can be traded with extra top speed for an overall reduction in lap time..........

[zac510]

Thanks kilcoo - so obvious, that only the second element stalls! Just needed someone to point it out

[kilcoo316]

I'm not sure whether the two elements can be treated seperately when the slot gap would close that much.

I'd expect the two wings to be 'stalled' in that the bound vortex/circulation whatever you want to call it has been broken, but downforce will still be created due to momentum exchanges - its kinda too tricky to say with conviction without some proper analysis.


Someday maybe I'll get round to doing the cfd sims, and be able to tell you all more.

[NickT]

For those of you who like Ferrari and their floppy wings I thought you might like one of these to

http://www.misco.co.uk/productinformati ... liate=7605

[Scuderia_Russ]

For those of you who like Ferrari and their floppy wings

Do any of the other teams make telly's to match their floppy wings?