By: DJ DeSpain
This weekend at Martinsville Speedway, the spoiler makes it return onto the back of Sprint Cup cars, eliminating the wing. The wing design made its debut at the 2007 spring Bristol race and made its exit at last weekendís race at the same track.
Prior to its elimination, drivers and fans alike did not care for the wing. Most of the reasons were in the cosmetic category in terms of car design appeal. Other reasons were more thought out in regards to affecting a carís handling ability during a race, particularly in passing cars or making the car looser on the track.
While the spoiler may make a difference in a carís handling, it still will not prevent a car from going airborne when hit.
Prior to the race last weekend at Bristol, a presentation was given in the media center by Bernie Marcus, Ford Racing Aerodynamicist, to explain what to expect with the reintroduction of the spoiler. With thanks to Dan Zacharias from Ford Racing Media Relations, Dan was able to provide RubbingsRacing.com a copy of Bernieís slide presentation along with Danís Q&A of Bernie.
Dan: If Iím a fan watching the Martinsville race at home, what difference am I going to notice from the wing to the spoiler?
Bernie: Hopefully, with the extra downforce that the car with the spoiler generates, it will improve the racing so people can race side-by-side and it will make it more exciting again.
Dan: Will going from the wing to spoiler stop cars from getting off the ground?
Bernie: The wing was a very low lift aero foil and before the new car got implemented, NASCAR did lift-off testing with both the spoiler and the wing, and, at the time, there was no difference in the lift-off numbers.† After the Ryan Newman accident last year at Talladega, NASCAR went back to the wind tunnel and did some more lift-off testing work with the wing and the spoiler and, again, there was very, very little difference.† So, really, the reason why the cars fly is not because of the wing, and going back to the spoiler is not going to prevent that.† The biggest problem is when the car turns, you get all this air that goes into the back, underneath the rear bumper and the underside of the car, and that just causes the rear of the car to lift.
Dan: What is being done now to keep that from happening?
Bernie: Itís an ongoing thing and NASCAR has been very proactive in lift-off testing and development with input from us and the other manufacturers.† Thereís a joint program going on, which will be ongoing for the foreseeable future, to try to come up with ideas to stop these cars from flying. The first product out of the recent lift-off test was putting the 3.5Ē tall decklid fin onto this car right now.† It reduces the lift-off numbers by a significant amount, but, nonetheless, thereís going to be ongoing development along the lines of, ĎHow do we stop air getting under the car?† And how do we evacuate the air in such a way that it prevents the car from lifting off?í† But, like anything, there are plusses and minuses to it.† We tried looking at reducing skirts. For example, you could take the left side skirt off the car and on a counter-clockwise spinout it would reduce the liftoff numbers quite a bit because it would let the air get out from underneath the car, but if the car would spin clockwise, you would actually pack more air under the car and the car would be more prone to lifting off.† Like everything, itís a compromise and before you implement something, you have to look at all the possibilities.
Dan: What does the decklid fin do?
Bernie: Itís just a vertical fin that runs from the back glass to the face of the spoiler.† When you see the car in motion you can hardly see it, but it does help get the side forces back that the car with the wing and curved end plates produced, so that regains the sideforce because with the spoiler alone the car actually lost rear sideforce, which is a stability thing, but the fin does actually bring the sideforce back to where the car was with the wing.† Itís a cheap thing too because itís just a $2 piece of aluminum.
Dan: Can you explain for fans how the downforce levels go from Truck to Nationwide to Cup?
Bernie: When the new car was created, and during the design process, NASCAR set specific aero targets.† They wanted the truck to have the highest amount of downforce and the Nationwide car approximately 20 percent less than the truck and the new Cup car to be approximately 40 percent less than the truck.† The thinking behind it from NASCARís perspective is they wanted the Cup car to be the most difficult and most challenging car to drive.† Thatís how those aero levels got created.
Dan: What will the spoiler do in terms of added downforce?
Bernie: It will bring it a little bit closer to the Nationwide car in overall downforce. It will put six, seven, eight percent more on it and also a slightly forward balance shift, which should help because one of the things with the new car was that it tended to understeer or push more, so, hopefully that should address it.† But, at the end of the day, you still have to work on the mechanical end and get your balance right, too.
Thanks again to Dan Zacharias for providing RubbingsRacing.com with this excellent Q&A and graphics to explain the spoiler versus wing differences.
Please join us on our Facebook page at facebook.rubbingsracing.com to comment on this article.