Delta Wing Discussion ONLY

[tjh8402]

Originally Posted by CyberMotor

Interesting statement here from Mike, "DeltaWing's greatest impact might simply be the stimulation of thinking about the future of the car, sportscar racing, and motorsports in general. But perhaps the starting point is, does motorsport have to really have to be relevant?"

While this question may have not been answered in some fans minds, I think the major manufacturers in racing have already answered this with a "Yes" in most cases. Obviously, Audi, Toyota, Porsche, Nissan and now Ford have responded with their answers and it is a 'Yes'. If the teams are attempting to justify the tremendous expenses to the Board of Directors, then attempting to explain that the expenses are just for fun and entertainment of a small crowd doesn't get you too far.

It's already having an impact on road car design, pending patent lawsuit settlement:

http://www.thetruthaboutcars.com/201...r/#more-646482

"...Nissan is apparently taking Bowlby’s concept and moving it from the race track to the street. It’s notable that Nissan is not calling it a concept. ”More than a concept, Nissan BladeGlider is both a proposal for the future direction of Nissan electric vehicle (EV) development and an exploratory prototype of an upcoming production vehicle from the world’s leading EV manufacturer,” said the manufacturer in a press release...
...Despite the unusual shape, Nissan says that the BladeGlider can meet crash regulations and be street legal and safe. They say that the mostly hollow front end acts as a large crumple zone and that the narrow nose presents a smaller area of impact, reducing the chances of an accident. At the same time, however, that narrow front end will be subjected to greater localized stresses than if the same force was distributed over a wider area."

[TME45]

I think the advantage of DW shape street car during crash is it is hard to impact directly. the car will always go sideways after crash, it will reduce lots of impact force then crash & stop directly.

[Maelochs]

The only benefit to the DWing layout was reduced frontal area and vastly reduced front drag with the narrow tires. On the street, where none of that much matters, the thing is a stupid joke.

As for "during crash is it is hard to impact directly" that's not the case simply because cars get hit form every angle on the street.Hit it from three-quarters front and it is the same as T-boning a conventional car.

Whatever. Manufacturers make weirdly-shaped cars because some people will buy cars just because they look weird.

[JamesH]

Originally Posted by Maelochs

The only benefit to the DWing layout was reduced frontal area and vastly reduced front drag with the narrow tires. On the street, where none of that much matters, the thing is a stupid joke.

As for "during crash is it is hard to impact directly" that's not the case simply because cars get hit form every angle on the street.Hit it from three-quarters front and it is the same as T-boning a conventional car.

Whatever. Manufacturers make weirdly-shaped cars because some people will buy cars just because they look weird.

Are you really saying that frontal drag is not important to a road car? Do you never drive over 30mph?

Back to the 60's immediately, we don't need no wind tunnel work for these road cars. It's irrelevant, Maeloch said so!

[Maelochs]

Considering that conventional cars can be built with Cd below .3 ... no, the advantage gained by the narrow nose is not relevant on the street.

Please try to think before attacking.

Sorry if you were so eager to be right that you had to interpret my statement as "Frontal area and drag don't matter on a passenger car." Maybe if your intent had been civil discussion instead of trying to score cheap debating points, you might have seen that what I actually wrote was "reduced frontal area and vastly reduced front drag with the narrow tires." (Emphasis added.)

The major source of drag on a street car is Not the wide front tires, but the passenger compartment, which can only be made narrower by using a two-seat fore-and-aft layout, which is useless for most passenger-car applications.

A street car Must be wide enough for two Real passengers side-by-side, and must be tall enough for those passengers to sit relatively upright, and must fit people smaller than Allan McNish and taller than Jörg Bergmeister.

The BladeGlider doesn't have a super-narrow nose. In fact, the nose is four feet wide, only about a foot narrower than say, a Honda Civic.

Furthermore the BladeGlider uses three-abreast seating, making the passenger compartment Wider than a normal car. Pretty obviously low drag via a narrower chassis wasn’t the effect they were aiming at.

The Nissan press release text doesn't even mention lower drag being a benefit.

" "The goal was to revolutionize the architecture of the vehicle to provoke new emotions, provide new value and make visible for consumers how Zero Emissions can help redefine our conception of vehicle basics,' Francois Bancon, division general manager of Product Strategy and Product Planning at Nissan, said in a statement."


So in summary, I did not say drag and frontal area were not relevant to street cars, but rather that the DeltaWing shape was not relevant for street cars.


If I had a history of posting idiotic trash here .... otherwise, when someone says something that makes no sense, maybe ask yourself if maybe it only makes no sense to You because you aren't taking enough time to think it through in your rush to win the "Gotcha" game.

Whatever.

[Pandamasque]

Originally Posted by Maelochs

The only benefit to the DWing layout was reduced frontal area...

Originally Posted by JamesH

Are you really saying that frontal drag is not important to a road car? Do you never drive over 30mph?

Back to the 60's immediately, we don't need no wind tunnel work for these road cars. It's irrelevant, Maeloch said so!

Wait a minute. Everyone keeps talking about the greatly reduced frontal area. But is it measured as a vehicle's cross section at around the front axle? There may be a sail on the back, but look sir, it has a pointy nose! DW's rear wheels aren't travelling in a vacuum, they stick out to the airflow, the rear of the car is still 2000mm wide... and in a road car there will be a passengers sitting above them too.

More efficient downforce generating devices and other drag reduction measures aside, I reckon the general shape of DW vs P1 gives only marginal drag reduction. If anything, in a rectangular cars you have 2 rows of wheels upsetting the airflow with a clear channel in the middle, in a DW you have 3 rows... same reason it's harder to avoid potholes in a Morgan 3-wheeler

[deltawing]

Originally Posted by Pandamasque

Wait a minute. Everyone keeps talking about the greatly reduced frontal area. But is it measured as a vehicle's cross section at around the front axle? There may be a sail on the back, but look sir, it has a pointy nose! DW's rear wheels aren't travelling in a vacuum, they stick out to the airflow, the rear of the car is still 2000mm wide... and in a road car there will be a passengers sitting above them too.

You are actually right. We see the frontal area is reduced, but if you do not reduce the "snail house" at the back, there is really no difference and you can go quite wild with different front width - the drag will be almost the same.

Originally Posted by Pandamasque

More efficient downforce generating devices and other drag reduction measures aside, I reckon the general shape of DW vs P1 gives only marginal drag reduction. If anything, in a rectangular cars you have 2 rows of wheels upsetting the airflow with a clear channel in the middle, in a DW you have 3 rows... same reason it's harder to avoid potholes in a Morgan 3-wheeler

The first part is true too, if you remove the "wings" on a P1 car and bring the DW to the P1 size, with no tires (but still a delta shape versus rectangular shape, and both with no aero devices), then there will be almost no difference.

The big difference is how a P1 car makes DF and how the DW makes DF. The first, due to so many things, including rules, makes greater, but less efficient DF (basically paying with more drag for given DF, the so called "lift to drag radio" otherwise expressed as L/D). The later has no wings, no splitter, no fat front tires and so it has quite higher L/D, even if the absolute DF number is not any near as high as on a P1 car.

I see the DW as a "package deal". Certain criteria have to be met SIMULTANEOUSLY for the package to work. Ruin that balance by shifting only one of the parameters and the whole thing collapses. The DW does not make much DF because the way DF is made is limited to the size of the underfloor and by the drag numbers it needs to achieve. It needs to achieve those low drag numbers so it can use less power. It needs to use less power so it can have lighter/smaller engine. It needs the smaller/lighter engine to reduce weight. It needs less weight because it makes less DF. It makes less DF because it needs less drag. It needs less drag so ...... there is the circle closing In my view this "circle" is extremely sensitive and as soon as one of these components goes "off" by even little bit, the net change of the "package" is quite more disastrous than it could seem by simply looking at the numbers changed in the equation.

And here is a side note, mainly to Mike: If all cars these days use some sort of "Ground Effect", then how do we differentiate the different ways they achieve those sorts of "Ground Effects"? If we use one term to name a variety of solutions/methods, then how can we differentiate them?

The reason I am not very keen to call what happens under the DW a "ground effect" method is basically what you can see here:



The above is a great illustration of what happens above a delta winged airplane. At high(er) angle of attack the trailing edges trigger powerful counter-rotating vortices, which then create even lower pressure in the region above the wings (in between the vortices). This is one of the reasons delta winged planes can increase the lift at lower speeds, all they have to do is increase the angle of attack to trigger the vortices.

Invert this at 180 degree around the longitudinal axis of the plane and you have the DW car. My point here is that if you remove the ground (hypothetically), the car is still going to make DF, just like there is no "ground" over the delta winged plane and it still makes lift. This is why I just feel it is not entirely and completely accurate to call the DW a "ground effect" car. Absolutely, the ground being in proximity is of huge importance as it helps to boost tremendously the low pressure numbers, but the actual principal of generating this type of force is not because the ground is there.

I wish the term "delta wing effect" could be used, as it is perhaps very clear at which exactly method/car people are referring to, but I also understand why it would not happen

Cheers.

.

[Maelochs]

Good post. Learning is fun. Thanks.

[MulsanneMike]

Originally Posted by deltawing

You are actually right. We see the frontal area is reduced, but if you do not reduce the "snail house" at the back, there is really no difference and you can go quite wild with different front width - the drag will be almost the same.



The first part is true too, if you remove the "wings" on a P1 car and bring the DW to the P1 size, with no tires (but still a delta shape versus rectangular shape, and both with no aero devices), then there will be almost no difference.

The big difference is how a P1 car makes DF and how the DW makes DF. The first, due to so many things, including rules, makes greater, but less efficient DF (basically paying with more drag for given DF, the so called "lift to drag radio" otherwise expressed as L/D). The later has no wings, no splitter, no fat front tires and so it has quite higher L/D, even if the absolute DF number is not any near as high as on a P1 car.

I see the DW as a "package deal". Certain criteria have to be met SIMULTANEOUSLY for the package to work. Ruin that balance by shifting only one of the parameters and the whole thing collapses. The DW does not make much DF because the way DF is made is limited to the size of the underfloor and by the drag numbers it needs to achieve. It needs to achieve those low drag numbers so it can use less power. It needs to use less power so it can have lighter/smaller engine. It needs the smaller/lighter engine to reduce weight. It needs less weight because it makes less DF. It makes less DF because it needs less drag. It needs less drag so ...... there is the circle closing In my view this "circle" is extremely sensitive and as soon as one of these components goes "off" by even little bit, the net change of the "package" is quite more disastrous than it could seem by simply looking at the numbers changed in the equation.

And here is a side note, mainly to Mike: If all cars these days use some sort of "Ground Effect", then how do we differentiate the different ways they achieve those sorts of "Ground Effects"? If we use one term to name a variety of solutions/methods, then how can we differentiate them?

The reason I am not very keen to call what happens under the DW a "ground effect" method is basically what you can see here:



The above is a great illustration of what happens above a delta winged airplane. At high(er) angle of attack the trailing edges trigger powerful counter-rotating vortices, which then create even lower pressure in the region above the wings (in between the vortices). This is one of the reasons delta winged planes can increase the lift at lower speeds, all they have to do is increase the angle of attack to trigger the vortices.

Invert this at 180 degree around the longitudinal axis of the plane and you have the DW car. My point here is that if you remove the ground (hypothetically), the car is still going to make DF, just like there is no "ground" over the delta winged plane and it still makes lift. This is why I just feel it is not entirely and completely accurate to call the DW a "ground effect" car. Absolutely, the ground being in proximity is of huge importance as it helps to boost tremendously the low pressure numbers, but the actual principal of generating this type of force is not because the ground is there.

I wish the term "delta wing effect" could be used, as it is perhaps very clear at which exactly method/car people are referring to, but I also understand why it would not happen

Cheers.

.

The use of vortex generators to enhance underfloor downforce is not unique to Deltawing at all. Stick your head underneath any US open wheel car from the late 80s on...and yes, DW, or any race car achieves a majority of it's underbody downforce with diminishing ride height. Hence no ground, no meaningful downforce. Vortex generators mitigate some of the ride height variability of downforce, but they don't eliminate it.

[Maelochs]

My understanding of "ground effect" is that the speed of the airflow under an object is increased as the volume of the space through which it flows shrinks which drops the pressure, so as the car gets lower, the suction increases (or more accurately, the underbody pressure decreases which gives more effect to the pressure above the body.)

The vortex generators are not necessary to this effect, though they obviously add to it, as I understand it.

I am not an engineer, and I would never argue with Mulsanne Mike. If my understanding is wrong, I am sure some of the engineers here will correct me, and if not, this is perhaps some clarification which all the engineers here know and take for granted everyone else knows, forgetting that we layman really don't know much except that we like racing.

[deltawing]

Originally Posted by MulsanneMike

The use of vortex generators to enhance underfloor downforce is not unique to Deltawing at all.....

Absolutely. My point here is that while most conventional cars use small vortex generators of all kinds to enhance underfloor performance (as you pointed), the DW is completely and solely relying on the vortex generators it has. If you interrupt those two vortices in a DW, the car loses everything. It is not a new nor unique method, but it is applied in a more unique way than it is in other more conventional vehicles.

[tjh8402]

Originally Posted by deltawing

You are actually right. We see the frontal area is reduced, but if you do not reduce the "snail house" at the back, there is really no difference and you can go quite wild with different front width - the drag will be almost the same.



The first part is true too, if you remove the "wings" on a P1 car and bring the DW to the P1 size, with no tires (but still a delta shape versus rectangular shape, and both with no aero devices), then there will be almost no difference.

The big difference is how a P1 car makes DF and how the DW makes DF. The first, due to so many things, including rules, makes greater, but less efficient DF (basically paying with more drag for given DF, the so called "lift to drag radio" otherwise expressed as L/D). The later has no wings, no splitter, no fat front tires and so it has quite higher L/D, even if the absolute DF number is not any near as high as on a P1 car.

I see the DW as a "package deal". Certain criteria have to be met SIMULTANEOUSLY for the package to work. Ruin that balance by shifting only one of the parameters and the whole thing collapses. The DW does not make much DF because the way DF is made is limited to the size of the underfloor and by the drag numbers it needs to achieve. It needs to achieve those low drag numbers so it can use less power. It needs to use less power so it can have lighter/smaller engine. It needs the smaller/lighter engine to reduce weight. It needs less weight because it makes less DF. It makes less DF because it needs less drag. It needs less drag so ...... there is the circle closing In my view this "circle" is extremely sensitive and as soon as one of these components goes "off" by even little bit, the net change of the "package" is quite more disastrous than it could seem by simply looking at the numbers changed in the equation.

And here is a side note, mainly to Mike: If all cars these days use some sort of "Ground Effect", then how do we differentiate the different ways they achieve those sorts of "Ground Effects"? If we use one term to name a variety of solutions/methods, then how can we differentiate them?

The reason I am not very keen to call what happens under the DW a "ground effect" method is basically what you can see here:



The above is a great illustration of what happens above a delta winged airplane. At high(er) angle of attack the trailing edges trigger powerful counter-rotating vortices, which then create even lower pressure in the region above the wings (in between the vortices). This is one of the reasons delta winged planes can increase the lift at lower speeds, all they have to do is increase the angle of attack to trigger the vortices.

Invert this at 180 degree around the longitudinal axis of the plane and you have the DW car. My point here is that if you remove the ground (hypothetically), the car is still going to make DF, just like there is no "ground" over the delta winged plane and it still makes lift. This is why I just feel it is not entirely and completely accurate to call the DW a "ground effect" car. Absolutely, the ground being in proximity is of huge importance as it helps to boost tremendously the low pressure numbers, but the actual principal of generating this type of force is not because the ground is there.

I wish the term "delta wing effect" could be used, as it is perhaps very clear at which exactly method/car people are referring to, but I also understand why it would not happen

Cheers.

.

Is that model's AOA that of cruise or a TO or landing? I know DW aircraft traditionally fly at least a little nose high, but way more so in slow speed situations (Concorde's need to rotate the aircraft to actually take off and her famous nose high approaches being examples that stick out in my mind). I'm asking because wouldn't the DW car need to be set up with a low nose and high rear of the car to create the same effect? I have seen the car run in person but did not note an extreme rake like that. Does anyone know for sure if they run that sort of set up or if that rake is inherent to the body of the car?

[deltawing]

Originally Posted by tjh8402

Is that model's AOA that of cruise or a TO or landing? I know DW aircraft traditionally fly at least a little nose high, but way more so in slow speed situations (Concorde's need to rotate the aircraft to actually take off and her famous nose high approaches being examples that stick out in my mind). I'm asking because wouldn't the DW car need to be set up with a low nose and high rear of the car to create the same effect? I have seen the car run in person but did not note an extreme rake like that. Does anyone know for sure if they run that sort of set up or if that rake is inherent to the body of the car?

The DW would need to be set low nose, high rear (as you correctly suggest!) IF the car was relatively flat underneath (if it was basically the inverted version of the plane on the picture). But the DW has the two "canals" or the way others call them, the two vortex generators, and those could be shaped to compensate for that, with the actual car not in need to be raked. But pictures suggest that the DW runs with quite some rake, so if that is the case, it is quite possibly because they are getting extra effect from being nose low/rear higher.

But to answer you Concord question: It is said that one of the major advantages of a delta winged plane is that at low speed you can lift the nose and with that change the angle of attack to a more aggressive one, which then triggers the vortices we see on that picture. At that point, the lift increases quite some and so such plane can land at lower speeds than the same plane with conventional wing. Another advantage of the delta winged plane is that it can fly super sonic with the air above the wing going sub sonic, due to the large sweep angle and all the interesting effects that has on the airspeed normal to the leading edge of the wing, but I am pretty sure we are already off topic, so let's leave it at that. but if you are interested, do some reading on the Net, it is quite fascinating

[deltawing]

tjh - actually here is a great video, just 30 seconds but it is the essential and you can see dynamically what is going on above a delta winged plane!

http://www.youtube.com/watch?v=5_jt4x_TpOI

It is very cool because the operator in only few seconds shows you how the vortices gets formed, how they get "lost", how they move, where they go, etc. And at the end he does quick comparison to an conventional wing plane.

[brandscooper]

Originally Posted by deltawing

Absolutely. My point here is that while most conventional cars use small vortex generators of all kinds to enhance underfloor performance (as you pointed), the DW is completely and solely relying on the vortex generators it has. If you interrupt those two vortices in a DW, the car loses everything. It is not a new nor unique method, but it is applied in a more unique way than it is in other more conventional vehicles.

There's nothing new under the sun!

http://1.bp.blogspot.com/_DsmBRYLt31...00/140_140.JPG

[deltawing]

Originally Posted by brandscooper

There's nothing new under the sun!

http://1.bp.blogspot.com/_DsmBRYLt31...00/140_140.JPG

Yes! And it was banned right away, because perhaps only few understood how to make it work

[MulsanneMike]

Originally Posted by deltawing

Absolutely. My point here is that while most conventional cars use small vortex generators of all kinds to enhance underfloor performance (as you pointed), the DW is completely and solely relying on the vortex generators it has. If you interrupt those two vortices in a DW, the car loses everything. It is not a new nor unique method, but it is applied in a more unique way than it is in other more conventional vehicles.

You'll have to qualify "more unique." More unique inasmuch as not having to pay attention to any regulations regarding the underfloor? Is that really "more" unique? I'm sure every designer would love to chuck the rule book out...

[MulsanneMike]

Originally Posted by deltawing

Y



And here is a side note, mainly to Mike: If all cars these days use some sort of "Ground Effect", then how do we differentiate the different ways they achieve those sorts of "Ground Effects"? If we use one term to name a variety of solutions/methods, then how can we differentiate them?

Furthermore to this, that's why we talk about tunnel cars, flat bottomed cars, etc. They're all assumed to be taking advantage of some sort of ground effect.

[MulsanneMike]

Originally Posted by Maelochs

My understanding of "ground effect" is that the speed of the airflow under an object is increased as the volume of the space through which it flows shrinks which drops the pressure, so as the car gets lower, the suction increases (or more accurately, the underbody pressure decreases which gives more effect to the pressure above the body.)

The vortex generators are not necessary to this effect, though they obviously add to it, as I understand it.

I am not an engineer, and I would never argue with Mulsanne Mike. If my understanding is wrong, I am sure some of the engineers here will correct me, and if not, this is perhaps some clarification which all the engineers here know and take for granted everyone else knows, forgetting that we layman really don't know much except that we like racing.

That's a very good explanation as far as I'm concerned.

[deltawing]

Originally Posted by MulsanneMike

You'll have to qualify "more unique." More unique inasmuch as not having to pay attention to any regulations regarding the underfloor? Is that really "more" unique? I'm sure every designer would love to chuck the rule book out...

Applied in a more unique way means that the entire car relies on those two giant vortex generators. Yes, others have used and use vortices to enhance DF, but as far as I know there is no car that relies solely on two vortex generators. Hence I chose the words "applied in more unique way". If there are no others configured this same way, it is quite unique application, while the method is perhaps not unique.

Designers may all love to throw the rule book and as far as I can tell no one is stopping them. Designers are free to leave the comfort of their big and established racing environments, throw away their salary checks, put their reputation on the line with something bizarre and go innovate, completely ignoring the rule book, without even knowing whether the fruits of their work is going to get even noticed or whether they are ever going to get paid for what they did..... who is exactly stopping any designer that you know from doing that?

[MulsanneMike]

Originally Posted by deltawing

Designers may all love to throw the rule book and as far as I can tell no one is stopping them. Designers are free to leave the comfort of their big and established racing environments, throw away their salary checks, put their reputation on the line with something bizarre and go innovate, completely ignoring the rule book, without even knowing whether the fruits of their work is going to get even noticed or whether they are ever going to get paid for what they did..... who is exactly stopping any designer that you know from doing that?

ACO rule book.

[optica]

Originally Posted by deltawing

Designers may all love to throw the rule book and as far as I can tell no one is stopping them. Designers are free to leave the comfort of their big and established racing environments, throw away their salary checks, put their reputation on the line with something bizarre and go innovate, completely ignoring the rule book, without even knowing whether the fruits of their work is going to get even noticed or whether they are ever going to get paid for what they did..... who is exactly stopping any designer that you know from doing that?

Ben Bowlby did and looks as though he landed a decent job from it.

[Maelochs]

Ben Bowlby had a decent job already, and always will have, because he is such a talented designer. And Bowlby had to struggle for a little while before he landed at Nissan--Thing is, after having designed so many successful cars, I guess he had the funds (and the respect needed to raise funds) to go out on a limb with a purely experimental car.

Originally the plan was to team up with Chip Ganassi and take over IndyCar--Nissan's ZEOD is his second or third emergency fallback position.

His plan for a single-seater flopped entirely, and his plan for a sportscar ... well I wouldn't call it a failure but I cannot call it a success after only entering two races and only completing one.

He had no way of knowing Nissan would like his plan and decide to build a Garage 56 entry ... and what happens after Le Mans 2014? The ZEOD can't race in any existing series.

Mostly what is stopping other designers from drawing up some completely illegal, completely unwanted pure experiment is the desire not to be broke and homeless.

[optica]

Originally Posted by Maelochs

Mostly what is stopping other designers from drawing up some completely illegal, completely unwanted pure experiment is the desire not to be broke and homeless.

Someone has to otherwise we would all still be in the caves. Many of the world's greatest innovators have ended up penniless. It goes with the territory.
"Completely unwanted" ?....might need to take a vote on that.

[nkoske]

Originally Posted by optica

Someone has to otherwise we would all still be in the caves. Many of the world's greatest innovators have ended up penniless. It goes with the territory.
"Completely unwanted" ?....might need to take a vote on that.

Not sure I see the innovation of the Delta-Wing.

• Lighter cars needs less energy to go the same speed. Not innovative, Porsche has done that forever, not to mention others. Basic high school level physics.
• Giant tunnels are more efficient than wings. Not innovative Again has been happening for some time.
• Torque vectoring. Not innovative, happened in F1 a long time ago and banned.
• The delta wing shape (narrow front track). Probably to only innovative thing, but I think at this point had to be proven not as good as a wide track. The delta wing has a greater power to weight than an LMP1 yet laps slower than a LMP2, which means it has to be losing it in the turns. Maybe someone has sector data that can disprove this, but the data I've seen seems to support it.

Have I missed anything?