Oval Racing Technology Issue 15 • November 2016 • www.racecar-engineering.com/stockcar NASCAR under cover This season’s developments in engines, cooling, simulation and aero FROM THE PUBLISHER OF CONTENTS his edition of Stockcar Engineering focuses turbines and wings for aircraft. However, then. Indycar once had the same, with its not only on the engineering developments clusters can rarely be manufactured – usually Gasoline Alley in Indianapolis, and now it is the Tin NASCAR, but also on the opportunities they just happen, as has occurred in the UK turn of North Carolina to be a breeding ground that are available within North Carolina for young, with Motorsport Valley. There, not only do the not just for new teams, but also technologies. up and coming graduate engineers. majority of Formula 1 race teams have their Not only is the cottage industry mentality Jon Gunn’s feature (page 12) perfectly race shops, but the supply industry has grown being created, but it can be rapidly expanded to illustrates the incredible growth of technology up around it, and is settled happily. There are help reach future markets. As we have written in North Carolina, America’s version of the UK’s opportunities, and moving teams, or specialities, elsewhere in this edition, that means periphery Motorsport Valley. It is a technology cluster in does not mean a family upheaval. technologies, such as driver in the loop simulators which teams, companies and engineers are able It is the same in Germany – World Endurance (page 18), and aerodynamics. to thrive. In the UK, the British government is Championship LMP1 teams Audi, Porsche and North Carolina is developing into a hotbed of pushing to develop these clusters all over the Toyota are within a few miles of each other and new opportunities for young engineers, who can country, including the south west where the personnel movement between them is common. not only bring their knowledge to the party, but Land Speed Record Bloodhound is being Those needing work after Audi’s withdrawal from also have the opportunity of working alongside the constructed alongside carbon blades for wind the WEC may have an opportunity close to home, established engineers who grew up developing cars through what our correspondent Danny Nowlan would describe as ‘hand calculations’. North Carolina has a big, bright future. Andrew Cotton Editor, Racecar Engineering CONTENTS 4 BENDING THE RULES 18 SIMULATORS 28 PWR PERFORMANCE NASCAR R&D boffin Eric Jacuzzi on How and why driver in the loop simulators Stockcar profiles the Australian company the drive to stamp out the use of flexible are beginning to play a much larger role in that supplies the entire Sprint Cup field components in the Sprint Cup NASCAR race engineering with its high performance cooling solutions 12 STOCKCAR INDUSTRY HUB 24 ROUSH YATES ENGINES 34 STOCKCAR SIMULATION We look at how a part of North Carolina An in-depth look at the close relationship Danny Nowlan continues his masterclass became the epicentre of the vibrant that’s been forged between NASCAR engine on chassis simulation for oval racing motorsport industry in the USA builder Roush Yates and Ford performance Produced by The Chelsea Magazine Company STOCKCAR ENGINEERING 15 - NOVEMBER 2016 - www.racecar-engineering.com 3 NASCAR - RULES ENFORCEMENT Individual tyre loadings on high banked tracks can exceed 4000lbs of force in the Sprint Cup, so the strength of parts needs to be strictly controlled Deflecting bodywork has made its way in to NASCAR and continues to evolve as teams continue to work to extract maximum performance 4 STOCKCAR ENGINEERING 15 - NOVEMBER 2016 - www.racecar-engineering.com Bending the rules Whether its fl exing in the suspension or the bodywork, bending the rules in the Sprint Cup can have a literal meaning. NASCAR’s R&D team reveals how the governing body is policing the use of fl exible parts By ERIC JACUZZI ut in the real world, away from defl ection play key roles in maximising driver (track) bar system and solid rear axle. e racing, fl exibility is a positive safety by absorbing energy to protect the rear axle is constrained fore and aft by two term. Being physically fl exible driver, both inside and outside of the car. trailing arm links with a Panhard bar holding is a good thing – you can move the axle in place laterally. e trailing arms in many ways without pain or Suspension Basics are connected to the car with bolts that act Odiscomfort. Being fl exible in life and career NASCAR’s inspection process at the track as a pivot, and are attached to the axle at means you can take things as they come, is similar to most series in that it focuses the rear with U-bolts. Camber at the rear bending when needed with the situations mainly on two areas: where the tyres are axle is achieved with specialised drive plates you’re presented with. and where they’re pointed, and inspection and highly engineered axle splines to deliver For racers, though, fl exibility has not of the aerodynamic surfaces of the car. Like power to the rear wheels while angled at been a word viewed in a positive light. most series, there are regulations defi ning something less than perpendicular, placing a Flexing could signal imminent failure of a the mechanical footprint of the car both great deal of stress on the axle components. component in the steering or suspension. for competitiveness and to preclude the Camber limits at the front and rear have For race stewards the world over, fl exibility negative eff ects that occur when things are been put in place to help protect the tyres has become a bane of their existence; a taken too far. ese measurements include from excessive wear, since there is not an dynamic phenomenon engineered to subvert limits on wheelbase, track, toe, camber and enforceable minimum tyre pressure without the inspection processes crafted to ensure weight distribution. e front suspension actively monitoring tyre pressures at all times fair competition amongst all competitors. is a typical double wishbone design, while throughout a race weekend. Individual tyre However, in the world of safety, fl exibility and the rear suspension is a three-link Panhard loading on higher banked ovals can exceed STOCKCAR ENGINEERING - NOVEMBER - www.racecar-engineering.com 5 NASCAR - RULES ENFORCEMENT Here’s a shot of the NASCAR Sprint Cup car’s three-link rear suspension showing Panhard (track) bar and the trailing arm links. 4000lbs of force, causing tremendous heat build-up and wear, with the right front tyre generally bearing the brunt of the punishment. While it is up to the teams to ensure their cars can safely manage the race distance, this does not prevent them from going too far and causing a tyre failure due to excessive wear or heat build-up. And, as is human nature, it’s much easier to lay blame on the tyre than to accept that a team played too close to the edge. Toe is another prescribed parameter, which is the amount of inward or outward turn in the tyres at zero steering input. Of particular interest is toe at the rear of the car. Toe, in conjunction with rear skew, essentially gives the car a form of rear steering. Rear skew is most simply defi ned as the diff erence between the left side wheelbase and the right side assuming the front axle is a straight line. So for a left Figure 1. This graphically illustrates front and rear sideforce build during a yaw sweep handed oval it is desirable to have a shorter left hand side wheelbase and a longer right hand increasing cornering capability dramatically. At racecar, there will be almost no lateral force, side wheelbase. e combined eff ect of rear toe the same ride height, downforce increases by since the car is by design symmetric. at and skew has implications to driver feel and car around 50lbs per degree of yaw angle achieved begins to change as the car enters the corner performance at diff erent points in the corner along with corresponding gains in sideforce. and the yaw angle increases. from a mechanical perspective, but the most Sideforce as a total magnitude is e current generation of Sprint Cup cars pronounced eff ect of rear skew is to deliver the informative, but does not tell the whole story. feature smooth and rounded fascias, which body of the car at a greater yaw angle to the air e real story is the diff erence between front means that as the body takes on a yaw angle, than there would be if there were no skew. and rear sideforce and how they change with the air fl ows nicely around the profi le of For clarity, yaw angle is the angle of the yaw angle. Let us presume we have a car headed the body on both the left and right sides, in body relative to the path of the car, while down the track on a straight with no rear skew. essence creating an aerofoil with a stagnation chassis slip angle is the angle of the chassis In this case, the yaw angle and slip angle will point somewhere on the nose of the car. As and tyres relative to the car’s path. e slip be one and the same. Based on the right-biased the car approaches its limit yaw angle, the air angle is dictated by defl ection of the tyres, and asymmetric tail design and spoiler off set, accelerates around the left hand front of the is generally around three to four degrees at this car will have something around 200lbs of fascia and down the side of the car, creating limit handling.