RE: Nissan powers DeltaWing Le Mans bid
Discussion
mat205125 said:
My observation, however, is that the car will be able to scribe a much straighter path through the tighter corners, e.g. the chicanes towards the end of the LaSarthe lap, due to it being much much narrower at the nose.
What sort of path do you expect the tail to be 'scribing', if not a similar one to the nose?BarnatosGhost said:
What sort of path do you expect the tail to be 'scribing', if not a similar one to the nose?
It's an interesting point though isn't it? Visions of a very messy overtake where the driver forgot about the back end.... you have to assume it must be difficult to place on track?Sorry - but even the music in the background of this clip sounds like a Batman theme...
http://www.youtube.com/watch?v=DlLZ3d-X8aY&fea...
http://www.youtube.com/watch?v=DlLZ3d-X8aY&fea...
doogz said:
The thing is, it doesn't really look like the front end is going to produce huge amounts of downforce?
It doesn't need to. The weight is mostly at the back and there's plenty of underbody downforce further back in the chassis. Tyre grip is proportional to the coefficient of friction of the tyre, you only need a lot of area when you have a lot of load through that particular tyre.And there's no link with RML - at least as far as the chassis goes. It started off as a Chip Ganassi project before it became DeltaWing LLC and then gained Nissan backing.
Visited there website. A lot of well know US motor sports people are linked to this. I hope it does well.
As it started as Indy race design, could it become a F1 car. Does any one out there have 100 million pounds to start an F1 team!
When are we going to see a road going Nissan Deltawing!
As it started as Indy race design, could it become a F1 car. Does any one out there have 100 million pounds to start an F1 team!
When are we going to see a road going Nissan Deltawing!
http://www.gordonkirby.com/categories/columns/thew...
That goes a long way to explaining it. Bear in mind this car was originally designed for Indy racing, hence the open cockpit.
That goes a long way to explaining it. Bear in mind this car was originally designed for Indy racing, hence the open cockpit.
MCBrowncoat said:
BarnatosGhost said:
What sort of path do you expect the tail to be 'scribing', if not a similar one to the nose?
It's an interesting point though isn't it? Visions of a very messy overtake where the driver forgot about the back end.... you have to assume it must be difficult to place on track?Surely the only advantage to this kind of shape is in some clever aero and/or aspiration/cooling (and even then, the impact on frontal area is negligible, since it still has a cockpit and engine between two wheels.)
BarnatosGhost said:
Surely the only advantage to this kind of shape is in some clever aero and/or aspiration/cooling (and even then, the impact on frontal area is negligible, since it still has a cockpit and engine between two wheels.)
The shape is indeed driven by aerodynamics. Eliminating the wings is intended to dramatically reduce the wake for closer, safer racing. The very narrow front end has significant drag benefits, even though it tapers out to a wide rear. Think of the wing span of something like Concorde and then consider the width of its nose... Overall the drag figure is half that of a traditional open wheeler (bearing in mind it started off as an IRL concept) and still a lot better than a conventional LMP.
The other benefit of getting the weight really far back is apparently stability. The centre of gravity acts much closer to where the majority of the tyre area is to be found and we're told it'll be more stable under braking than a normal design as well as easier to recover from 'over the limit manoeuvres'.
Basically, less weight and less drag prompts a virtuous circle. It's designed to return the same performance as a modern IRL car (or LMP) on half the engine output and half the fuel consumption.
gary71 said:
So the frontal area is the same as any other race car of similar width then?
I will file this one under the 'interesting but pointless' category!
Maybe there's an aerodynamicist here who can explain it fully, but there is a lot more to drag than total width. Think of the tear drop shaped canopies on an LMP coupe or the delta wing design of a fighter aircraft ... all use a tapered design to great effect despite considerable overall width.I will file this one under the 'interesting but pointless' category!
Just seen the video of Marino Franchitti driving the car, can't say it looks brilliant in the corners to be honest, he seems to have to be very tentative. I just can't see how it's going to be as quick as the LMP cars other than in a straight line. And personally I think it looks pretty stupid.
Chris71 said:
BarnatosGhost said:
Surely the only advantage to this kind of shape is in some clever aero and/or aspiration/cooling (and even then, the impact on frontal area is negligible, since it still has a cockpit and engine between two wheels.)
The shape is indeed driven by aerodynamics. Eliminating the wings is intended to dramatically reduce the wake for closer, safer racing. The very narrow front end has significant drag benefits, even though it tapers out to a wide rear. Think of the wing span of something like Concorde and then consider the width of its nose... Overall the drag figure is half that of a traditional open wheeler (bearing in mind it started off as an IRL concept) and still a lot better than a conventional LMP.
The other benefit of getting the weight really far back is apparently stability. The centre of gravity acts much closer to where the majority of the tyre area is to be found and we're told it'll be more stable under braking than a normal design as well as easier to recover from 'over the limit manoeuvres'.
Basically, less weight and less drag prompts a virtuous circle. It's designed to return the same performance as a modern IRL car (or LMP) on half the engine output and half the fuel consumption.
I'm not doubting the truth of your post, I just don't quite 'get it'. Also, pushing all the weight backwards and reducing tyre size up front commensurately seems to run counter to the received wisdom of mass centralisation and 50/50 distribution.
Though the idea of fast, close racing without the mucky air of wings and downforce sounds great. Which begs the question: Why hasn't it always been done like this?
MCBrowncoat said:
My understanding of this car was that it was designed with a extremely small frontal area to aid straight line speed?
The frontal area doesn't seem actually any smaller, as that's governed by the max width - so the rear track, which is the same as any other LMP, and the height of the chassis. Arguably you have INCREASED frontal area by having to have a really tall nose to cover the front wheels; and the rear wheel arches are no longer shadowed by the fronts. So for no real reduction in frontal area, you have lots of plan area to generate nice big boundary layers on (not good for drag).The article linked above is interesting, but I can't get my head around their explanation of the grip for the front wheels. They say there is less load on the front due to the lack of mass. Fine... except that load (whether that comes from downforce or mass) = grip. The tyre grip doesn't increase linearly with load, so there is benefit to lowering the total load, but it seems at odds to do that. The Nissan GT-R weights 1600kg+ because the designer wanted 400kg of load on each tyre, consistently. Weight was the way to do it, as aero loads vary. So how does having almost no load over the front avoid understeer, they say the balance is very rearwards - that will give understeer.
Plus, the rearwards weight distribution arguably traps them into running the centre of pressure even more rearwards if they want to maintain straightline stability, especially important for this car given the lack of front track (although helped by the enormous wheelbase). IMO the design seems to be be compromising an awful lot from a chassis dynamics point of view, just to be different. But if it works well, I'll be the first to say I was wrong.
BarnatosGhost said:
Interesting post. I can see the 'point' in a shape like concorde, for displaying as much of the frontal area in wing format as possible, but I don't get how that translates to a car, for whom the wheels are a 'bad thing', rather than a 'good thing' like a wing.
I'm not doubting the truth of your post, I just don't quite 'get it'. Also, pushing all the weight backwards and reducing tyre size up front commensurately seems to run counter to the received wisdom of mass centralisation and 50/50 distribution.
Though the idea of fast, close racing without the mucky air of wings and downforce sounds great. Which begs the question: Why hasn't it always been done like this?
Because nobody has tried anything like it before.I'm not doubting the truth of your post, I just don't quite 'get it'. Also, pushing all the weight backwards and reducing tyre size up front commensurately seems to run counter to the received wisdom of mass centralisation and 50/50 distribution.
Though the idea of fast, close racing without the mucky air of wings and downforce sounds great. Which begs the question: Why hasn't it always been done like this?
Chris71 said:
The shape is indeed driven by aerodynamics. Eliminating the wings is intended to dramatically reduce the wake for closer, safer racing. The very narrow front end has significant drag benefits, even though it tapers out to a wide rear. Think of the wing span of something like Concorde and then consider the width of its nose...
Concorde's delta wing shape is nothing to do with drag, more to do with the shock wave from supersonic flight. RenesisEvo said:
The frontal area doesn't seem actually any smaller, as that's governed by the max width - so the rear track, which is the same as any other LMP, and the height of the chassis. Arguably you have INCREASED frontal area by having to have a really tall nose to cover the front wheels; and the rear wheel arches are no longer shadowed by the fronts. So for no real reduction in frontal area, you have lots of plan area to generate nice big boundary layers on (not good for drag).
The article linked above is interesting, but I can't get my head around their explanation of the grip for the front wheels. They say there is less load on the front due to the lack of mass. Fine... except that load (whether that comes from downforce or mass) = grip. The tyre grip doesn't increase linearly with load, so there is benefit to lowering the total load, but it seems at odds to do that. The Nissan GT-R weights 1600kg+ because the designer wanted 400kg of load on each tyre, consistently. Weight was the way to do it, as aero loads vary. So how does having almost no load over the front avoid understeer, they say the balance is very rearwards - that will give understeer.
Plus, the rearwards weight distribution arguably traps them into running the centre of pressure even more rearwards if they want to maintain straightline stability, especially important for this car given the lack of front track (although helped by the enormous wheelbase). IMO the design seems to be be compromising an awful lot from a chassis dynamics point of view, just to be different. But if it works well, I'll be the first to say I was wrong.
D'uh... It looks like the Batmobile. It's going to win. The article linked above is interesting, but I can't get my head around their explanation of the grip for the front wheels. They say there is less load on the front due to the lack of mass. Fine... except that load (whether that comes from downforce or mass) = grip. The tyre grip doesn't increase linearly with load, so there is benefit to lowering the total load, but it seems at odds to do that. The Nissan GT-R weights 1600kg+ because the designer wanted 400kg of load on each tyre, consistently. Weight was the way to do it, as aero loads vary. So how does having almost no load over the front avoid understeer, they say the balance is very rearwards - that will give understeer.
Plus, the rearwards weight distribution arguably traps them into running the centre of pressure even more rearwards if they want to maintain straightline stability, especially important for this car given the lack of front track (although helped by the enormous wheelbase). IMO the design seems to be be compromising an awful lot from a chassis dynamics point of view, just to be different. But if it works well, I'll be the first to say I was wrong.
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