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"There's a lot of junk out there today. If you want it straight, read Kirby." -- Paul Newman

The Way It Is/ The Delta Wing's virtuous circle

by Gordon Kirby
Three months ago this space presented the first detailed analysis of the Delta Wing concept. Ben Bowlby's ideas and design concepts have excited many fans around the world but there's also been quite a lot of resistance to such radical thinking. In fact I don't believe I've heard so many frivolous, uninformed comments about motor racing in many years and it's sad to see many people who have no engineering or technical knowledge so easily dismiss the Delta Wing concept.

As we all know, innovation has always been the driving force behind racing and that spirit continues today in Formula One and international Le Mans-type sports car racing. But it's been largely driven out of American racing and there's no question that most fans want to see the sport return to this spirit. Many traditional fans dislike the trend to spec cars and want to see new and different cars and engines.

While Lola, Swift and BAT have produced intriguing proposals for the 2012 Indy car, the Delta Wing is the only one of the five contenders for the contract whose goal is to buck the spec car trend and encourage a variety of engines and manufacturers. This week on the eve of this year's 94th Indianapolis 500 I'm going to explore the Delta Wing in more detail.

"The concept of the car was unanticipated," designer Bowlby remarks. "We did not set out to create a car with narrow front track, a wide rear track and 72.5 percent rear weight distribution. We set out to produce a modern, efficient, relevant, high-tech, low-cost, high-value racing car that had the latest in knowledge in safety and accident prevention built into it as well as longevity, recyclability and modern materials. Our goal was to integrate all of these aspects into the car.

"The shape of the car came together out of realizing that if we truly wanted to make a halving of the fuel burn we needed to reduce the drag dramatically. We had to halve the drag in gross terms and we actually went a little bit further than that. In order to get our power-to-weight ratio we had to halve the weight because we were going to have half the power. That led us to realize that we had to enclose the wheels to reduce the aerodynamic drag of the exposed, rotating wheels."

© Paul Webb/LAT USA
The challenge was how to achieve these goals without making a sports car rather than an open-wheel single-seater.

"We decided to do that by keeping the front wheels within the monocoque," Bowlby says. "We started with a single wheel and tire assembly ahead of the driver's feet inside the chassis and we ended up with two narrow tires, which is a better solution than a single tire. We used quite sophisticated simulations from a vehicle dynamic standpoint and we used a pretty sophisticated CFD to develop the shape of the car aerodynamically.

"The goal was to have a car that raced well in traffic, that had a very broad operating envelope and gave the driver opportunity to overtake and race the car in a fan-friendly way where you could actually see the driver at work. That means having a car that is on the edge of control, but in such a way that the driver can maintain that edge of control in a wide range of operating conditions."

At Long Beach last month Bowlby told the drivers that in contrast to the disbelief of many uneducated observers the Delta Wing driver will enjoy more feel and be able to place the car more precisely on the track. These properties should also make the car much more exciting to watch.

"At the end of the day this is an edge sport," Bowlby observes. "You want the fans to be drawn to watch because it is clearly difficult to drive the car and they are amazed by the skill because it's apparent and they can feel the sensation of the driver being on the edge. It's got to be a visceral experience for the fans where their hearts are racing and they hold their breath hoping that nothing bad is going to happen. So we wanted to produce a racing car where you could see that the cars were on edge and you could see the balancing act at work.

"In order to do that, particularly at high speed, the car has to be moving around quite a bit. You therefore need an aero package and a tire and vehicle geometry package that can accommodate that exploration at the edge of the performance envelope. We found in the simulations that we could achieve a fundamentally oversteering or loose race car that was actually relatively easy to control because of the weight distribution, the low polar moment of inertia, the overall light weight and the aero configuration."

The current Dallara Indy car loses much of its downforce when it swings through more than two and a half degrees in yaw angle. This is a key reason why it's so difficult for the drivers to be able to pass each other.

"Our car is stable in yaw and allows high slip angles to be achieved and only slow the car down rather than causing a spin or accident," Bowlby explains. "We wanted to create a car where the driver could explore the limit of adhesion and speed and the fans could see it. Because the car is light and responsive at high slip angles it will slow-down due to aero drag without losing downforce. If we could achieve those goals the drivers will be able to try some pretty wild moves and the consequences aren't too horrendous. So there will be more attempts to make passes without the consequences being too severe and the car should put on a better show.

"We've also designed the aero package to run in traffic better than the current car. In fact, it's twice as good in terms of retaining the downforce when you're running a car length behind. This is critical because if the following car loses five, ten or twenty percent of its downforce there's no hope of getting through the corner. Even one percent loss of grip is a sufficient detriment that you can't get on terms with the car ahead of you. We worked very hard to disciplne ourselves to take aero solutions that didn't halve the aero performance of the following car and I think we've managed to do that to a very significant degree."

© Ben Bowlby
The absence of traditional front and rear wings is another factor in the improved responsiveness and raceability of the Delta Wng concept.

"The removal of wings ahead of the front axle and behind the rear axle and their interaction with the underbody and the car and their wake characteristics all help to put all the performance in the underbody," Bowlby says. "This method of creating the downforce makes a very efficient and stable package with a very low yaw sensitivity to the downforce and very high efficiency from a lift-to-drag ratio standpoint. I think we're going to have a car that feels very light, is very nimble and can be taken to high slip and yaw angles without compromising the ability to control the car.

"At the same time the car will also have very high performance. In our simulations with only 300 horsepower the car is faster on the street and road tracks than the current car. In our simulations at the Sao Paulo track for example we were two and a half seconds a lap quicker. So it's quite exciting from a performance perspective."

Bowlby was delighted with last month's first wind tunnel test of the Delta Wing at the WindShear tunnel in Charlotte. Ganassi's team uses the tunnel to test its NASCAR Sprint Cup cars so Bowlby and his team of engineers are familiar with the facility. Bowlby was delighted that the first wind tunnel test of the full-scale Delta Wing model validated all of his computional fluid dynamic (CFD) numbers and also confirmed the effort Bridgestone/Firestone put into developing and building tires specifically for the Delta Wing.

"We built our Chicago Auto Show demonstration car to our CFD data so it was a very interesting exercise to take it to a full-scale, rolling road tunnel with Firestone's tires," Bowlby comments. "The front tires are what we will start testing on. Firestone have built proper racing tires specifically for the Delta Wing. They're not show tires. Firestone have done their lab work. They loaded the tires to full load and ran them for over six hours at well over 200 mph. They also ran them at over 250 mph at full camber and full lateral force to make sure the tires were everything Firestone hoped they would be. They were comfortable that we could run the tires in the tunnel.

"We ran the full-scale model in the WindShear tunnel to gather data on drag and downforce in straight ahead and multiple degrees of yaw angle. To see how the forces from the CFD work compare to the forces measured in the full-scale rolling road tunnel was very interesting. If our CFD numbers were right then for sure we were going to be able to do a 230 mph lap at Indianapolis with 300 horsepower. Assuming that the downforce numbers were accurate we would have the grip in the turns and the tire design would have been matched to those loadings.

"In the wind tunnel the downforce was only a minute percentage different than our CFD numbers. It was very, very close, as were the drag numbers. They were well within our expectations of accuracy. So the wind tunnel test was another box checked. The car is on target for doing what we set out to do. After the wind tunnel test we now have lots of confidence."

Bowlby and his engineering team have also focused on making the Delta Wing much safer for the driver. To this end they incorporated a new and much more crushable composite material called Tegris in the Delta Wing's chassis.

"Tegris is made by Milliken and Company in Spartanburg, South Carolina," Bowlby relates. "Tegris is an all-polypropolene composite and it's a very interesting material. The polypropolene is drawn into thin, tape-like ribbons and woven into a cloth. Because of the way it's been processed the cloth can be stacked in a pile and then consolidated under temperature and pressure such that it turns into a very stiff and yet light matrix of pure polypropolene. But it retains the original ribbons of material so the property of the material is not a uniform homogenous, isotropic material. It behaves more like a carbon fiber in a pre-preg condition where the interlaminar bonds between the plies of the material have a different property than the material itself.

"The result is that we have a fully recyclable, low-cost material with high stiffness, extraordinary strength-to-weight ratio and also enormous energy absorbing properties without a failure of the structure. In an impact the interlaminar bonds are broken but the material itself is not ruptured. It becomes quite strain-rate sensitive so that the faster you hit something the more it resists, which is a very valuable property. It makes it good, for example, for preventing bullets passing through it so it's used in armored military vehicles. It's also environmentally-friendly and recyclable."

Instead of having a traditional aluminum honeycomb core the Delta Wing's chassis will be manufactured from Tegris with inner and outer carbon fiber skins.

© Ben Bowlby
"We will end up with a carbon-skinned, Tegris-cored chassis which gives us enormous anti-intrusion properties and all the stiffness we require for the chassis, plus light weight, recyclability and low cost. We have replaced carbon-epoxy to a degree by using Tegris and using Zylon panels for anti-intrusion.

"When the chassis is subjected to some of the really awful crashes that occur from time to time the Tegris is unlikely to rupture. The interlaminar bonds may get broken and the carbon skins may fracture but the driver will be cocooned inside a survival cell that remains intact rather than leaving his or her feet hanging out of the front of the chassis. Tegris is a very tough, very resilient material with a great deal of elongation before it fails and that's something that carbon fiber doesn't possess. It should be a really big step forward in race car chassis safety."

After Alex Zanardi's terrible accident at the Lausitzring in 2001 Kevlar/carbon side panels were added to Champ cars and Zylon side panels were required for F1 cars. Three years ago the IRL also mandated the addition of Zylon side panels to its existing Dallaras.

"But Zylon is heavy and extremely expensive," Bowlby says. "Done right, it's $7,000 per panel. They're expensive and not particularly recyclable and they weigh a lot. Of course, as you push the weight of the car up so the energy that needs to be absorbed by the chassis for a given speed also goes up. The heavier the car, the greater the amount of potential energy that needs to be absorbed in a progressive manner to insure that the driver is uninjured.

"One of the nice things about a light car is you don't have as much energy to absorb. You still need the distance over which to absorb it so you need to design to give as great as possible a length of time over which the energy is absorbed by the chassis to reduce the peak g-loading experienced by the driver. It's a virtuous circle. You keep the overall weight down and the amount of energy you need to absorb is also reduced."

Like the BAT design, the Delta Wing places the driver in a more upright seating position than any recent Indy cars.

"We've positioned the driver in what we now understand to be better ways than we have been positioning them for a long time. We have positioned the driver in a more upright position so the driver's spine is closer to being vertical. This is very important for surviving heavy forwards or rearwards impacts without putting too much strain on the spine and neck and causing basal skull fractures."

Because the Delta Wing's 'Global Racing Engine' is a non-stressed member, unlike today's traditional F1 and Indy cars, the Delta Wing will absorb much more energy in heavy rear impacts.

"In fact, the entire design of the car helps in this regard," Bowlby says. "With a small, non-stressed engine positioned inside a composite cradle we've ended up with a structure surrounding the engine and gearbox that is readily crushable. So if you have a rear impact we have a very large area of crushable structure.

© Ben Bowlby
"You will remember when the first stock-block-based IRL cars came out with a very strong and stiff bellhousing/gearbox package without an attenuator and without the 'Safer' barrier--which has been such a huge step in safety for the drivers--so that when the drivers backed into the wall a lot of them were getting pretty severe back injuries. That was an example of too high a g-load spike in deceleration on hitting the wall because the gearbox, bellhousing and the engine didn't crumple or shorten up. One of the nice things about having a non-structural engine is you can put it inside a structure that is designed to crush in a big impact. It's a nice safety feature."

The Delta Wing's pursuit for improved safety and performance is also evident in its electronic differential.

"The differential is a very exciting area as well. We will actually have a useful 'diff'. Rather than being a passive device that is very inconsistent and very temperamental it suddenly becomes your ally. It's a balance-adjusting, driver-adjustable tuning device. It will be just like saying I need a few more points of stagger on an oval. You'll be able to dial it in. Firestone don't have to make staggered tires. They don't even have to make the tires to be exactly the same. It won't matter. It's something that can be accommodated in the design and control of the 'diff'.

"There will be a big economy and savings there and higher efficiency. You won't be dragging a tire down the straights and if a driveshaft does fail it won't spear you into the wall. You'll just drive along on one wheel instead of having a big moment. You'll basically have an open diff situation where you'll lose drive until the software says, oh, you've got a broken driveshaft. Here's a bit of limp home help."

Delta Wing will source most of its materials and suppliers from Indiana.

"Our goal is to manufacture as much of the car in Indianapolis as we possibly can," Bowlby says. "The rest of the material and component supply that we can't get in Indy we will get in Indiana and across the United States. We're pretty comfortable that we will have a truly American-built car. That's a very exciting prospect because there hasn't been an American Indy car for many years."

Bowlby emphasizes that Delta Wing does not intend to be a chassis manufacturer in the traditional sense, but expects to create a substantial number of new jobs.

"Chip has been a huge part of facilitating, encouraging and mentoring and being a visionary in knowing that an initiative needed to be taken. But it's very important to realize that Delta Wing will be its own entity. There may be ownership by a number of team owners, including Chip. But our goal is to be an independent, neutral, stand-alone entity to support the series and the teams and drivers.

"Delta Wing does not intend to be a manufacturer. Our goal is to entirely outsource the materials and components and the manufacture of the car itself. We will be an inspection and quality assurance house. All the parts that are fed into the series will pass through Delta Wing to assure that they are made to published drawings and that they meet quality standards.

"We will be using the wider Indiana job pool. We're anticipating around 160 jobs being created during the three years of the design, development and manufacture of the initial batch of cars. That's a fairly significant number. It's quite hard to create that many jobs."

But at this stage Delta Wing is on hold as far as building and testing a prototype.

"We have kept moving forward although we are under a sort of restraint as the 'Iconic' committee goes through its process and comes out with a recommendation," Bowlby comments. "That's put us into a holding pattern. We are effectively not at liberty to spend anybody else's money until we know whether we will be the next Indy car. When a decision is made it will define the course of our expenditure. If we are in the driving seat we will immediately activate all our plans to move forward on all fronts.

"But we are unfortunately completely on hold with the manufacture of anything. We cannot afford to continue to build without the decision of the 'Iconic' committtee. We're basically on hold until we have a decision from the committee.

© Ben Bowlby
"I'm not saying we won't find other avenues for the car should the IndyCar series decide on a different direction. If we are not selected we will pursue a different route, but that's a different story.

"Potentially, it's only seven months to have a car up and running. So if they decide in the middle of the summer we can expect to have the car running shortly after Christmas. It's not that we've been doing nothing. In fact we've been refining the design in many different areas. We've spent the time to rework the concepts, particularly in the transmission, suspension, cooling, attachment of chassis structures and roll hoop and chassis manufacture details. We've spent a lot of time refining those details to make a very light, very efficient, cost-effective vehicle."

Bowlby and Ganassi believe it's essential for IndyCar to get away from the spec car label. They hope to achieve this through Bowlby's 'open-source' concept.

"We're convinced that when you look at the spectrum of racing's sustainability and value that a one-make series does reduce costs to a degree," Bowlby remarks. "But it also reduces value to an unacceptable degree so the equation doesn't work. Nor does the other end of the spectrum where Indy car racing once was in different economic times and Formula One still is today where you have a rulebook and everyone knocks themselves out spending as much money as you can raise. Neither of those two models are really sustainable.

"It is absolutely our goal to help get IndyCar back to pre-eminent, premier status racing where it is a global brand and globally-recognized with the involvement of multiple auto industry manufacturers. We believe that the best approach is what we are proposing in the open-source protocol.

"By publishing the design and the criteria for legality the parts will be built to a published design. That will simplify the tech-inspection process, remove ambiguity from the rules and make it a fair competition. We also control the costs and make obsolete the development that is exclusive to a team. What's the point in spending a bunch of money if you have to be able to sell that part to anyone who wants it and you have to publish the design?

"We feel that in open-source publishing of designs there is a really exciting new territory that's not been explored in motorsport. It would be great to be the first there. Obviously, it's been facilitated by the advent of the Internet. Not that the Internet is new, but we're all learning how to use it and be entertained and informed by it and control our businesses and the interaction of our businesses through the Internet.

"So it's very exciting and I think it's a huge opportunity for IndyCar. Obviously, we need TV, radio and newspapers. But there's also the Internet and how you engage that and how the younger demographic particularly interact and communicate through the virtual sources and networking. So it's a very exciting opportunity.

"For economy reasons we are going to produce the kernel of the open-source so that we have a start-up point and everybody has a car that we hope can accept one of a number of different engines and everybody can get running. At that point on day one everybody will have the same thing. But day two begins the differentiation and diversity. The story of the technical interest and the development and innovation will begin on day two which will be a huge part of the story to maintain interest. Because it's truly going to be accessible it should be a fascinating story to the fans."

The 1.6 liter turbocharged four-cylinder 'Global Racing Engine' has been discounted by many people. But Bowlby has no doubt that the 'GRE' age is coming.

"First of all, there will be 'Global Racing Engines'," Bowlby observes. "Some are already up and running and a number will be up and running later this year. The horsepower projected is in the range of 300-350 and I think you can assume most of them will be in the 320-330 bhp range. The rules have been announced for the World Rally Championship--a 1,600 cc direct-injection, 'stock-block' turbocharged four-cylinder. That's a reality.

"It's not going to be very useful for powering a conventional car because you need much more horsepower. If you did a really big job to improve the drag you might be able to get down to 500 hp or so. But if you've got a heavy car your power-to-weight ratio is still out of balance so you will have to have even more power to make road and street racing look exciting.

© Ben Bowlby
"The fact is horsepower is expensive. When you put a lot of power down your tire costs shoot up in just the size of the tire and the rate at which you wear out the tires, the driveline and transmission. Everything is heavier and has to be bigger because it's under more stress. If you can carefully bring the power down and bring the weight down in line with it you could argue that the stress isn't that much improved. But the tire is much smaller and the driveshaft is much smaller. They don't need to be as big and heavy. Everything is a virtuous circle.

"I just don't agree that a spec Honda engine is a good thing and I don't think heavyweight cars are good," Bowlby adds. "With a conventional car you need 750+ horsepower on a road course and the trouble with that is big horsepower is never cheap. It always costs you dear. It's a nightmare. It's always expensive.

"We can get an engine from a number of different quality racing engine builders whether it's AER, Cosworth or Ilmor. These entities know how to make racing engines and we can have a bespoke engine as well. I'm still very keen on fuel flow control as the regulation system for the engine. Ultimately, I think it would be very exciting."

Bowlby points out that the federal government is very interested in American racing moving towards a fuel flow formula.

"This is not only my opinion but also of some people in the Department of Energy and the EPA and other sanctioning bodies around the world," he comments. "Controlling the amount of energy that can be consumed against time per second is very relevant.

"For the American public it is a question of national security. Energy consumption is extremely important. It has implications for the country economically, environmentally and from a national security standpoint. Sixty percent of America's trade deficit is in purchasing foreign oil. Using less is the way to be environmentally and economically savvy. But none of us want to give up any performance. So we're showing that you can have all the performance of today's Indy cars but for half the impact, which is a pretty big change.

"When you think about transporting tires for Firestone or cars around the country or fuel delivery to the racetracks, if we're burning half as much the cost of transporting those things and the environmental impact in using those materials is all halved. It's a really healthy step and I think it will give us a lot of marketability with important American corporations, if not global corporations, so that IndyCar can be at the forefront of a new trend in truly relevant environmental responsibility and actually show that racing is a cool, exciting and worthwhile activity."

Under new president Jean Todt's direction the FIA appears to be embracing the 'GRE' for all its motorsport categories. In fact, the FIA confirmed last month that it wants F1 to adopt the 'GRE' in 2013.

"It's very exciting to hear that the FIA are looking at a four-cylinder turbo with direct injection," Bowlby says. "I think they're talking about adding KERS which for a road track-based series makes an enormous amount of sense. It is quite a high initial development cost and I think at this point IndyCar is not quite ready for that. But that's the beauty of the Delta Wing. There's no reason why that couldn't become part of the program. Every year we could reduce the amount of fuel and the engines would be forced to become more efficient so we could recover some of our braking energy in a KERS system or perhaps some form of hybridization. But all these opportunities are available at low cost in the Delta Wing package."

If the 'GRE' becomes the FIA's base engine for all its major categories and IndyCar goes a different direction Indy car racing will be entirely outside the international world. It would be stuck as a regional, domestic series running to its own rules with a Honda spec engine and few if any prospects of competing engine manufacturers--largely unchanged in fact, from today.

© Ben Bowlby
"I don't know what the impact would be on IndyCar to have F1 go to the same powertrain or if IndyCar doesn't go that route and F1 does," Bowlby remarks. "These are pretty interesting questions.

"I think if we don't show leadership it would jeopardize IndyCar's premier status brand. I think appearing risk averse would be very detrimental to IndyCar's position. Leadership is critical and one of the things racing can do is provide leadership in terms of technology and innovation. I'm committed to helping IndyCar in any way possible make choices that show global leadership in terms of relevance and environmental responsibility. I feel there is enormous value in drawing new spectators and a new demographic to the sport and great potential for IndyCar for the future.

"I think sponsors and suppliers are going to insist on an environmentally-conscious image," Bowlby adds. "If our cars are only a green-wash, that's going to hurt us financially."

Bowlby also believes the Delta Wing will move Indy car racing from being perceived as a poor man's version of F1, as it has been for thirty or more years, into a uniquely identifiable form of racing in its own right.

"Another thing the Delta Wing could potentially provide IndyCar is that since the rear-engine revolution of the late sixties you could argue that Indy cars have been wannabe F1 cars," he observes. "We would provide a unique and easily identifiable image of an Indy car. It would be recognizable the world over as an Indy car.

"If the 'Iconic' committee makes their recommendation and the Delta Wing becomes the future Indy car you would have something that is globally recognizable as an Indy car. If IndyCar can really get behind us and insure that we do everything we can to build the brand of the new Indy car around the Delta Wing there will be no question that it's not an F1 car. There are a plethora of these one-make, wannabe F1 series, but this would not be a wannabe F1 car. It would be its own new, relevant brand and I think that's hugely powerful."

Bowlby admits he's had some sleepless nights worrying that the Delta Wing might be too radical for many tastes. But he says the worldwide fan reaction in favor of the concept and the recent successful wind tunnel tests have assuaged those concerns.

"I've been crapping my pants as we've been going through this process because it seemed like a huge risk to go out on such a limb. But it made too much sense to ignore it. It had so many virtues and so few drawbacks and as we go through the development and analysis and testing we keep finding that we are able to check boxes off successfully.

"We've run the tires at speed and Firestone was very excited about the performance of the tires. The brake package, chassis package, transmission and aero packages and the detail of the cooling package are all coming together. It's extremely cool because nobody in the world has done this kind of car before. So you feel like an explorer all the time. But the concept is holding water."

Bowlby concludes with a brief synopsis of why IndyCar should choose the Delta Wing over its competitors.

"I think it's very important to say we are not trying to make a cheap car. We're trying to make a really exciting high-tech, high-value car that is worthy of the premier status name of IndyCar. We think it's going to be high value. We know we can bring the engine costs down dramatically by a factor of ten frankly from where they are today. So this is an opportunity that shouldn't be missed, particularly in this economic environment.

"I'm sure Randy Bernard has some very different opinions on his 'Iconic' committee. Let's hope they make some wise choices."

Auto Racing ~ Gordon Kirby
Copyright 2010 ~ All Rights Reserved

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