Lotus E20 VD

[bhall]

End plate slits never intake air from outside the wing. Their sole purpose is to bleed pressure that would otherwise be shed as drag-inducing vorticies, and the vehicle's vaw rate never has anything more than a superficial effect on this activity. All things being equal, the faster a car goes, the more pressure there is to bleed. It's as simple as that. A rear wing never knows if it's turning right or left, only if it's going fast or slow.

That's but one of the reasons why I simply do not understand this reluctance to acknowledge the simple elegance of Lotus' blown wing solution. It works when a pressure threshold is met and it doesn't work until that pressure threshold is met. Simple. Easy. Beautiful.

[N12ck]

End plate slits never intake air from outside the wing. Their sole purpose is to bleed pressure that would otherwise be shed as drag-inducing vorticies, and the vehicle's vaw rate never has anything more than a superficial effect on this activity. All things being equal, the faster a car goes, the more pressure there is to bleed. It's as simple as that. A rear wing never knows if it's turning right or left, only if it's going fast or slow.

That's but one of the reasons why I simply do not understand this reluctance to acknowledge the simple elegance of Lotus' blown wing solution. It works when a pressure threshold is met and it doesn't work until that pressure threshold is met. Simple. Easy. Beautiful.

yes that is true , however if it does have the DRS involved aswell which it could well have, which we dont know yet, it could work in the same way but allow the DRS to feed more air into the pipe to allow it to activate earlier to increase the pressure inside the tubing, or of course it could be completely passive and work how you described and how I described earlier

[bhall]

The part you're not getting is that there's no need for such a capability for this thing to work, and beyond that, there's no added benefit to having such a capability in the first place. One only needs a single source of pressure to detach the flow around the duct that's been added precisely to detach flow. Anything more than that makes such a system that much more difficult to control, because it adds unneeded complexity that carries no additional benefit.

There's no need to blow, or to put it precisely, to relieve pressure along the outside of the rear wing, because A) there are slots in the end plates to do just that, and B) teams are allowed a section between the end plates and the rear wing to place as many slots as they deem necessary to accomplish whatever the find necessary.

Yanno?

[N12ck]

The part you're not getting is that there's no need for such a capability for this thing to work, and beyond that, there's no added benefit to having such a capability in the first place. One only needs a single source of pressure to detach the flow around the duct that's been added precisely to detach flow. Anything more than that makes such a system that much more difficult to control, because it adds unneeded complexity that carries no additional benefit.

There's no need to blow, or to put it precisely, to relieve pressure along the outside of the rear wing, because A) there are slots in the end plates to do just that, and B) teams are allowed a section between the end plates and the rear wing to place as many slots as they deem necessary to accomplish whatever the find necessary.

Yanno?

You dont need the ddrs for it to work, no, but you could make it work with the DRS if needed which is what I am saying, I understand how the passive system works without DDRS i explained it earlier on, I believe it would be more beneficial with the DRS as it can not only be pressure activated as we know the passive system is, but also the DRS could activate it with a fluidic switch,

my diagram does not blow along the sides of the rear wing, it takes air from there to allow the system to activate with DRS than activating later on via pressure, I think we have had a misunderstanding and crossed wires somewhere

[Ral]

I wasn't talking about the slits at the top of the end plates though, but the ones on the inside of the end plates underneath the bottom of the static rear wing.

[bhall]

[...] I think we have had a misunderstanding and crossed wires somewhere

And I will accept full responsibility for that, because, evidently, I'm not as good as explaining matters as others were when they've explained matters to me. Plus, there's the whole only-child thing that I believe I've explained before. (Or maybe I'm just assuming that internal dialogue was outwardly expressed, too.)

There's no need for direct DRS activation of the E20's system. This is because the team more or less knows the airspeed of the car at any given point of the track where they want this system to work. That knowledge enables them to tune the system via the dimensions of the duct slits to work within the ranges their knowledge of the vehicle's airspeed has defined.

DRS activation is needless because it's needless (yes, you read that right, and see: above and all of my other various explanations) and because it limits the capability of the system to the constraints of the rules governing the use of DRS. The Lotus system can be used regardless of the session and regardless of how far the E20 trails a rival.

That it doesn't rely on DRS for anything is what makes this system so valuable.

[Cam]

If nothing else, that makes the most sense. Why make a system just like the Mercedes DRS activated one when you can take it to another level? Having something that is tuned to operate when you need it most, regardless of session or time gap, makes the most sense. If they can get this working, they really are the dark horse. It's almost RBR EBD territory. Imagine an advantage on every straight and easy corner.

[hollus]

My gripe with a passive system that simply switches on above a certain speed (defined by a pressure threshold) is the same we had for the F-ducts in 2010.
This downforce reducing system would still be on at the beginning of the braking areas, and as flow won't reattach immediately, will stay "on" for a good part of those, at least in the longest straights, affecting braking performance. Since it is only at the rear... can one balance this with brake bias?
Not saying that top speed benefits could not eventually outweigh this, just pointing out the negatives.

[bhall]

Those are valid concerns. However, I think it's probably helpful if you don't look at this system as one that is switched on and off for any reason at any speed. (A dynamic I've heretofore perpetuated anyway. Sorry.) It's always on, and its effects are then determined by the vehicle's airspeed.

Think of the constant flow vented from the duct slits as a sort of wing in and of itself. This "wing" just changes size depending on how fast the car is moving. At low speed, when the system is fed by, and releases, comparatively little pressure, the "wing" is small and has very little effect on the air flow it deflects. At high speed, when the system is fed by, and releases, much more pressure, the "wing" is much larger and therefore has a much larger effect on the air flow it deflects.

That this system deflects air flow is probably a better way to explain its effect rather than saying it detaches air flow. Again, I'm sorry my explanations haven't been more clear. At some point, I'll hopefully dot every T and cross every I, and then everyone can marvel at the simplistic elegance of this system the way I do now.

[CMSMJ1]

^^ That is one of the better posts I have read in ages - nicely summarised =D>

[MarkedOne8]

So, there are posibilities to see this system even in 2013?

[bhall]

Yes. Not only that, but I think we're likely to see teams at least testing derivatives of this system - I've decided to call it VD, by the way - at Spa and Monza.

The more I think about it, the more I see how the effects of a VD might be rather profound - you should now clearly see why I've dubbed it VD - because it has the potential to virtually eliminate unwanted rear-wing drag from a car's aerodynamic profile.

As a car accelerates and requires increasingly smaller levels of downforce (and becomes increasingly sensitive to drag), the system sheds a corresponding amount of downforce and, more importantly, its associated drag. Later, as the car slows down to take a corner, the system then re-establishes downforce proportionally.

In a weird context that perhaps only makes sense in my head, a VD creates a stealth wing, because the vented flow is essentially an invisible, self-adjusting aerodynamic device.

I did some simulations last night.. the model is a bit incomplete because I did not put the slits in the end-plate. but anyway, before and after tests show that the slits reduce the Down-force and drag.

I will post some picture tonight after work.

The downforce drasticallty drops...And this is when all the air from the scoops is blown through the pylon slits. Remember though, I have not modelled the end-plate slits yet. I do not know how that will affect the model. Will do that tonight

I eagerly await your data. Just remember that the lower vent is absolutely vital to the functionality of a VD. It must extract enough air so that the system doesn't become completely pressurized and choke. Otherwise that would occur very quickly given the diminutive size of the duct's slits versus the amount of air the scoops take in.

[Huntresa]

Would it be possible to have more pylons connected to the RW and blow more of the RW or is the middle enough with this system?

[bhall]

I don't see why not. That actually seems like the next logical step.

[superdread]

I don't see why not. That actually seems like the next logical step.

Only the middle 15cm of the wing are allowed to have pylons, so rather not.