Delta Wing Discussion ONLY

[EricS]

Doesn't surprise me that the DW was denied LeMans entry. Nissan wouldn't like it to be there either to take away any of their ZEOD thunder.

[bjohnsonsmith]

Originally Posted by EricS

Doesn't surprise me that the DW was denied LeMans entry. Nissan wouldn't like it to be there either to take away any of their ZEOD thunder.

I would have liked to have seen them both race.

[joeb]

Originally Posted by EricS

Doesn't surprise me that the DW was denied LeMans entry. Nissan wouldn't like it to be there either to take away any of their ZEOD thunder.

I have never seen a LeMans entry form, but I assume there is a box to check saying what class you are applying to. And if DW had to pencil in another box called "other" I am no surprised the ACO said no.

It is somewhat funny though, and I wonder how often the ACO has had teams apply that don't meet any of the class regulations?

[deggis]

Originally Posted by EricS

Doesn't surprise me that the DW was denied LeMans entry. Nissan wouldn't like it to be there either to take away any of their ZEOD thunder.

It was about this year's entry.

[deggis]

Originally Posted by joeb

I have never seen a LeMans entry form, but I assume there is a box to check saying what class you are applying to. And if DW had to pencil in another box called "other" I am no surprised the ACO said no.

It is somewhat funny though, and I wonder how often the ACO has had teams apply that don't meet any of the class regulations?

Entry form has its own checkbox for "car displaying new technologies".

That refers to section 3.13 of the supplementary regulations for LM24, which seems to mean Garage 56, but there is also the "non conventional cars" provision in the technical regulations (this has been there at least since 2000 btw).

[Machin]

It's been a while since I posted one of my Deltawing vs the rest comparisons, but thought I would do it now the Coupe has a couple of races under its belt; you know, give it a chance:-



The Power to weight of the Deltawing Coupe is calculated from the figures posted in the latest Racecar Engineering, modified for low fuel; RCE says total weight with driver and fuel is 590kg. The total fuel is 40 litres, so if we say it runs with just 10 litres in qualifying, then 30 litres less cuts about 23kg from the weight, i.e. about 567kg, and the quoted 350bhp.

Now, I know I've never been a big fan of the Deltawing, but even so, I didn't think it would be this bad... 40% more power to weight than an LMPC, and still lapping slower... Its not really a new car these days, so I don't accept that excuse anymore....is it simply the tyres?

[miatanut]

Originally Posted by Machin

Now, I know I've never been a big fan of the Deltawing, but even so, I didn't think it would be this bad... 40% more power to weight than an LMPC, and still lapping slower... Its not really a new car these days, so I don't accept that excuse anymore....is it simply the tyres?

The Panoz effort has been pretty pathetic compared to the All American Racers/Highcoft effort.

[Maelochs]

Agreed. Not to put down the Panoz crew, but Highcroft has always been a first-class operation. Plus, they were in on it from the very start.

The Panoz team might be over their heads and have empty wallets, and less test time as well.

Sad, because that car could run a Lot better if it were running well.

[Adam43]

I thought it was obvious that it wouldn't lie on the normal power to weight lap time curve.

[CyberMotor]

I still wonder if the roof has altered the concept? It was originally designed to be an open cockpit and open wheel vehicle. The airflow and weight balance are part of the special abilities of the car. Those parameters have now changed. They seem to be different now with the coupe.

[broadrun96]

Think there is something to that thought, it's not like the DW was a simple design and they have changed the airflow with the roof, new tires, and a new engine without the assistance of the budgets of Nissan and Michelin enhanced by the profile of LM. It was a great thought but think the DW needs a big budget and it can only be hurting the small potential it had for sales. Personally don't think we will see any on track next season and I've always been a defender of the project. And it looked a LOT less Ace and Gary as a spyder.

[CyberMotor]

I would say it is a huge opportunity (pressure?) at the PLM for the DW to impress and show what it can do. Hoping they are able to shine.

[Machin]

Originally Posted by Maelochs

Agreed. Not to put down the Panoz crew, but Highcroft has always been a first-class operation. Plus, they were in on it from the very start.

The Panoz team might be over their heads and have empty wallets, and less test time as well.

I must say, I'm less inclined to say its the team, and more inclined to say that it was just the track itself, although in fact the lap speed comparison at Le Mans looks very much like these latest charts, although back then the Deltawing had just 300bhp:-



If we focus just on the Porsche curves, its clear to see where the car is losing time compared to the "rectangular" prototypes:-



With the American Le mans Series tracks not having the long straights of Le Mans, I would summise that the Deltawing just doesn't have the opportunity to make up for its slow speed through the corners....

So really, my question comes back: is it simply the tyres? Is it the Delta wheel layout? Or is it not making the claimed downforce?

[Machin]

Another interesting piece of analysis:

If we take the VIR comparison chart, and follow the rectangular car dotted curve back to the same lap speed as the Deltawing (113mph), we see that a rectangular prototype would need a power:weight of 400bhp/ton in order to achieve the same lap time as the Deltawing.

Back in the earlier years of the last decade the LMP2 category was preceded by the LMP675 category... where the cars weighed just 675kg. Assuming a 75kg driver (750kg total weight), an LMP675 (built with today's aerodynamic accomplishments), would need just 300bhp to achieve 400bhp/ton and hence the same lap time; that's less power than the current Deltawing!

If we assume that our "lightweight LMP" has the same 350bhp as the current Deltawing, it could weigh a maximum of 875kg with driver (say 800kg without) to achieve the 400bhp/ton and hence the same lap time. Or put another way: the penalty of the Deltawing layout/tyres/aero (whichever is causing the problem) is equivalent to about 300kg of weight on a rectangular layout prototype....

[Maelochs]

Excellent. That is the first analysis I have seen which appears to be both factual and unbiased, which shows that the DWing concept might Not actually be the Next Big Thing in sportscar design.

Back when this was an active topic, a lot of people wanted to see a whole class of cars with DWing weight and displacement and as many wheels/wherever as the designer wanted.

Quite possible the rectangle cars would have dominated. Can't tell, but based on the numbers we do have ...

I am not against he DWing but I am pretty strongly in favor of facts.

[deltawing]

Originally Posted by Machin

.... So really, my question comes back: is it simply the tyres? Is it the Delta wheel layout? Or is it not making the claimed downforce?

Hi Machin,

Do we actually know what the "claimed downforce" numbers are? Do we also know what compound the tire supplier has provided for the car in comparison to the tires supplied to the rest of the LMP cars? You always bring very interesting points!

Cheers.

[HJJ]

Originally Posted by Maelochs

Agreed. Not to put down the Panoz crew, but Highcroft has always been a first-class operation.

Sad, because that car could run a Lot better if it were running well.

It wasn't Highcroft running the team, it was guys from RML supplemented by many of the same guys that are there now. It's still teething problems with the coupe (aero) and the new elan engine.

[CyberMotor]

Originally Posted by HJJ

It's still teething problems with the coupe (aero) and the new elan engine.

Let everyone know in every department that the pressure is on to excel...

[HJJ]

Originally Posted by CyberMotor

Let everyone know in every department that the pressure is on to excel...

Trust me, they know.

[yamato]

It sure was fast in a straight line at Road America,......

It was likely a great concept for oval racing,.....

Just not so great If you have to make any turns that might require any sort of mechanical grip.

[Machin]

Originally Posted by deltawing

Hi Machin,

Do we actually know what the "claimed downforce" numbers are? Do we also know what compound the tire supplier has provided for the car in comparison to the tires supplied to the rest of the LMP cars? You always bring very interesting points!

Cheers.

Figures published in Racecar Engineering in 2012 claimed a Cl.A of 2.39m^2 for the Le Mans variant, or put another way, 4.215m^2 per ton.

Figures from the rather excellent Mulsanne Corner suggest an LMP2 has a Cl.A of 3.276m^2, or 3.38m^2 per ton.

in terms of downforce per ton the Deltawing were claiming more than an LMP2, which, if everything else were equal, should mean higher cornering speed. Since they're not making decent cornering speed we can only summise that either they aren't making the claimed downforce, or the tyres and/or chassis are causing a bigger loss of cornering speed...

Unfortunately getting to the bottom of which area is causing the lack of cornering speed isn't going to be easy! You would hope that since the Deltawing isn't constrained by the normal aero rules it should be better than an LMP2, so that would definitely point in the direction of the underperformance being a tyre/chassis issue....

[deltawing]

Originally Posted by Machin

Figures published in Racecar Engineering in 2012 claimed a Cl.A of 2.39m^2 for the Le Mans variant, or put another way, 4.215m^2 per ton.

Figures from the rather excellent Mulsanne Corner suggest an LMP2 has a Cl.A of 3.276m^2, or 3.38m^2 per ton.

in terms of downforce per ton the Deltawing were claiming more than an LMP2, which, if everything else were equal, should mean higher cornering speed. Since they're not making decent cornering speed we can only summise that either they aren't making the claimed downforce, or the tyres and/or chassis are causing a bigger loss of cornering speed...

Unfortunately getting to the bottom of which area is causing the lack of cornering speed isn't going to be easy! You would hope that since the Deltawing isn't constrained by the normal aero rules it should be better than an LMP2, so that would definitely point in the direction of the underperformance being a tyre/chassis issue....

Let's assume for the moment that the numbers you found are correct for the car in LM and Petit LM configuration for 2012. Let's also accept for the moment that the car performed as expected (especially at PLM). The issue is that we don't know what really happened after. Yes, everyone knows roughly what was changed, but there are no actual (and accurate) figures of how much exactly weight the car gained and most of all how was the weight distribution affected.

We also do not know how was the car developed aerodynamically. Looking at pictures from all sorts of angles, it looks like the visible part of the lower body was not changed at all. Now the closed cockpit was added and everyone is talking how this is entirely new design and the car completely different, but looking at pictures the lower part still looks the same.

If the above is true and there was no actual aero development (downforce related, not the visible openings here and there on the car), then adding just the closed cockpit would perhaps hurt things as perhaps there would be some lift added. On the other hand the closed cockpit would be lighter, so that would help, but it would also change the pressure distribution/balance in comparison to the cabrio, in ways perhaps nobody knows.

And then there are the tires, which nobody talks about in terms of actual compound and where do they stand in comparison to the LMP1/2 compounds. We did not know much about the Michelins, we know even less about the Bridgesotnes and I bet we will know close to nothing about the Contis next year.

What I am noticing is that every time it is wet, the car is doing much better than in dry conditions (in relation to how other cars do on wet vs. dry), which is pretty interesting. I guess there is little to do right now but to wait and see how they do at PLM and then see what the future will be.

[gustavobamba]

Despite all the things written in this thread "IMHO" D. Panoz and the team working with him needs to rething th DW concept.

The DW concept is a fresh thing in endurance motorsport but they need to evolve to diferent level. They need more than a roof in the car...

[Machin]

Originally Posted by deltawing

If the above is true and there was no actual aero development (downforce related, not the visible openings here and there on the car), then adding just the closed cockpit would perhaps hurt things as perhaps there would be some lift added. On the other hand the closed cockpit would be lighter, so that would help, but it would also change the pressure distribution/balance in comparison to the cabrio, in ways perhaps nobody knows.

The latest edition of Race Tech magazine has an article on the Deltawing Coupe (as does the latest Racecar Engineering, for anyone that is interested). In the Race Tech article it says that adding the roof reduced drag by (if I remember correctly) 8 to 9%, with a similar REDUCTION in downforce. This was accompanied by CFD plots, so I think it is fair to say that the team know to a pretty high degree of accuracy what they are talking about.

If we apply the 9% reduction in downforce to the "2012 LM" downforce figures we can see that the downforce per ton figure is still higher than that bandied about for the latest LMP2 cars, so all else being equal you would expect the car (even in Coupe-guise) to be quicker through the corners.

Clearly "all else" isn't equal since the car is slower through the corners. Either that or the released downforce figures aren't actually being achieved....

In terms of the tyres... does anyone know how regularly they changed the tyres in the latest race? Certainly at Le Mans in 2012 they changed tyres less often than the normal cars... suggesting they could've gone quicker if they had used a more aggressive compound and changed tyres more often.....

[FstrthnU]

Perhaps the Bridgestones just aren't up to par like the Michelin or Dunlop LMP tires?