The Scoop On The Scoops
In reality of course, there is no indictment. But some within the winged car community do have serious doubts about Chrysler's tire clearance explanation, with perhaps just a few actually believing in a conspiracy of sorts. So although the indictment charged above is a fabrication, it does serve to set the tone for a discussion that will be of particular interest to many of the winged car faithful.
Stock car racing rose from its post-depression, southern roots to nationwide prominence in the 1960's, due in large part to national television coverage. With this new widespread exposure, auto makers saw the potential for increased revenue, as a factory's success on the track seemed likely to boost sales of its cars across the country. As the 1960's progressed, factory involvement in the sport continued to escalate as each auto maker worked to gain an edge on the other. This one-upmanship culminated in the late 1960's with the production of the 1969 Dodge Charger Daytona and 1970 Plymouth Road Runner SuperBird.
Stock car racing rules in 1969 required a certain minimum number of "street legal" automobiles be produced before that particular model would be permitted to participate in racing events (the Homologation Rule). This was an effort by race sanctioning organizations to defeat the factories' growing tendency to produce a small number of purpose built race cars that would never be sold to the car buying public. After all, this was a "stock car" series, where the vehicles competing were supposed to have some reasonable association with the ones driven by Mr. and Mrs. John Q. Public. It was thought if that association was lost, much of the race ticket buying public would be also.
With the Homologation Rule firmly in place then, the racing cars and their street legal alter egos looked very similar, at least on the outside. This requirement blurred somewhat when it came to the cars' interior, chassis and motor, as concessions had to be made for safety and performance reasons. For example, if a racing car was in an accident, unnecessary interior pieces could strike the driver or fuel a fire. And any type of extra weight in the car served only to penalize performance, both in the car's speed and handling. Besides, most race fans would rarely have a chance to see anything other than the outside of a racing automobile, so with external appearances maintained, the "stock" image of the car was perpetuated.
In the case of the 1969 Dodge Charger Daytona and 1970 Plymouth Road Runner SuperBird, both were produced in minimum quantities in a street legal configuration, with an additional few having been specially built for racing only. Both racing and street cars carried the scoops and fender holes because whatever their function, they had to appear on the street legal cars so that they could also be included on the racing versions.
The street legal 1969 Dodge Charger Daytona and 1970 Plymouth Road Runner SuperBird sported fender scoops that were similar in appearance, although they would not interchange. SuperBirds came with two types of scoops, the much more common rounded version and the relatively rare flatter version. A few street SuperBirds reportedly left the factory with one of each! The scoops on both street cars were always body color.
Street car scoops attached to the fenders via five studs integral to the scoops that aligned with holes drilled in the fenders. These studs were threaded on the end and nuts were screwed onto them from underneath the fender to hold the scoops in place. The racing car scoops were similar in external appearance to the ones affixed to the street cars, but were often smoothed at front to blend with the contour of the fender top in order to smooth airflow over the fender. The racing scoops were sometimes attached by studs but in other instances were actually made part of the fender through metalwork fabrication techniques.
All street car scoops were manufactured by Jo Ad Industries in a plastic material. The Daytona version was approximately 1 5/8" in height (at its highest point) by 9" in width (at the opening) by 14" in length. The SuperBird's were 1 3/4" in height (at the highest point on the rounder version), 8 1/2" wide and 14" deep. The racing versions were similar in size and typically made of plastic or in some cases metal if integral to the fender top. Metal scoops seemed to become more prominent as the racing cars matured through the 1970 season.
All racing Daytonas and SuperBirds had large holes in the fenders underneath the scoops. Street legal Daytonas had holes in the fenders also, but they were relatively small (roughly 4" in diameter) and were covered with a screen welded in place to the underside of the fender. Street legal SuperBirds were produced and sold with the scoops but had no holes cut in the fenders. The opening found beneath the racing scoops on either car was generally much larger than that found on the street Daytona and never had a screen over it. The hole was, in fact, normally as large as practicable given the dimensions of the scoop shell that covered it.
Chrysler Corporation has always claimed that the scoops were included on the cars as part of a design fix to prevent the front tires from rubbing against the fenders. They asserted that during times of especially heavy loading (from centrifugal force as the cars passed through banked turns at high speeds, for example) the tires would impact the fenders. And why would this be bad?
A tire rubbing a fender would cause friction, which would in turn slow the car. Over the length of a race, this could cost the driver positions on the track (and the burning tire odor wouldn't be very pleasant either). In addition, because the tire and fender were impacting each other, the front of the car could not sink as low as it otherwise would. This represents a lost opportunity for additional speed, because the lower a car is the faster it is, all other things being equal. The car is faster because drag associated with air flowing under the car is lessened and the center of gravity is lowered, which allows it to corner more quickly. Lastly and most importantly, the friction and resultant heat that comes with tire impacting fender may cause a catastrophic failure of the tire. A very dangerous situation given the speeds the cars were running and their proximity to the very hard concrete walls.Why The Scoops?
Ironically, Chrysler's explanation as to why the scoops were on the cars really doesn't answer the question asked. It instead answers, why were there holes in the fenders? And why it would be necessary to cover these holes with scoops, or anything else for that matter, has never been adequately addressed by Chrysler. One possible explanation put forward centers around concerns that the front tires might pick up debris and toss it into the stands, causing injury. This explanation is quickly debunked by one word - Indianapolis. The open wheel cars have raced there and at many other venues for decades without fear of tire debris injuring spectators.
Another possibility concerns the NASCAR rules at the time and whether
there was some sort of requirement for full fenders or a mandate that holes
in fenders be covered or masked in some fashion. From the 1969 NASCAR Rule
Book, Section 20, Subsection 2:
So, if the factory fender stampings came without holes, Paragraph g mandated that no holes could be cut without the approval of NASCAR inspectors, and the purpose of the holes or alterations must have been for no reason other than tire clearance. Apparently Chrysler had read the rules and was taking no chances - thus the appearance of holes, cut by the factory in the street Daytona Charger fenders. And interestingly, there doesn't seem to be anything in the rules making a cover for factory cut holes necessary, so the question remains, why the scoop shells if they weren't required?
It should be noted that changes or clarifications were probably made to the NASCAR Rule Book during the 1969 season. It is possible that some of these revisions did directly impact the form the fender scoops assumed (or that they appeared at all) on the mid-year Daytona. Also, because it's simply not possible to write a rule for every circumstance, it may well be that at some point NASCAR made it clear (written or not) that it didn't want holes in the fenders clearly visible. Perhaps the scoops were an attempt to keep the stock, "full-body" look which NASCAR no doubt had an interest in maintaining (to differentiate its cars from rival open wheel series' cars). Another possible explanation for the scoop shell mounted over the fender hole originates from the vacuum that will be created directly behind the trailing edge of the scoop as the air rushes by. More on why this is important just a little later.
On a related subject, winged car guru Dave Patik recently confirmed that he had asked Chrysler engineers in the late 1970's why street Daytonas had holes cut in the fenders, while SuperBirds did not. Dave was told that Chrysler wasn't confident enough about how NASCAR might interpret its own rules when it came to racing Daytonas' scoop holes, and thus holes appeared on street Daytonas as a strict interpretation of the Homologation Rule would demand. Once Daytonas had made several race appearances during the 1969 race season, Chrysler apparently got a feel for the degree of latitude NASCAR would allow in its rules interpretation for the winged cars, and the decision was made not to cut the street SuperBird fenders. This saved time and expense on a program that was short on time and long on expense. And of course Chrysler's call on this was correct, as all NASCAR racing SuperBirds were allowed to compete with holes cut in the fenders under the scoops. Interestingly, Chrysler Technical Service Bulletin No. 70-23-6, dated January 6, 1970, instructed dealers on how to put holes under the street SuperBird scoops if the buyer requested it. Perhaps this bulletin was an attempt on Chrysler's part to hedge its bets a bit, in case NASCAR got a little more stringent with its rules for the 1970 season. With the bulletin having been published before SuperBirds were even officially deemed eligible for NASCAR competition (this happened January 14, 1970), it may have served to bolster whatever arguments Chrysler might have presented on why the racing SuperBirds should sport fender holes even though the street cars did not.Chrysler Perpetuates The Tire Clearance Explanation
The seed of Chrysler's tire clearance explanation was planted in the automotive press in the late 1960's and it has born a great deal of fruit. If any article about the winged cars from the last 30 years is reviewed and the scoops are discussed, it will almost certainly mirror the Chrysler tire clearance scenario. As part of the research for this article, it took the author less than one hour to locate the following excerpts from several different automotive sources:
In the years since the Daytona and SuperBird debuted, doubts have emerged about Chrysler's scoop function explanation. This chorus of doubt has come primarily from the street car owners, as the last winged car was permitted to appear in sanctioned stock car competition in September, 1972. As of that time, the scoop issue was dead in racing circles, as concerns there turned toward preparing eligible models for next year's competition. Most racing winged cars were re-skinned to later models and the sheet metal wearing the scoops was disregarded or re-worked, as Chrysler did not include the scoop devices on any of its later models. Any interest that the racers might have had in learning more about the function of the scoops most probably went away at that time.
The street Daytonas and SuperBirds (as well as most all big motor, high performance cars) fell into disfavor with the mainstream motoring public after the gas crunch of 1973. In addition, emission controls and insurance rates made the cars even less popular, and of course the winged cars were no longer in the limelight on the tracks. The fair weather friends of the winged cars took a rain check and a relatively small, dedicated group of enthusiasts were all that remained. The work of a small portion of this dedicated and resilient group remains today in the guise of the Daytona-SuperBird Auto Club and the Winged Warriors/National B-Body Owners Association. And what was one of the many topics that was bantered about among this core group of enthusiasts? The scoops of course. This is evident in the excerpts presented earlier that were taken from the 1976 and 1977 Winged Warrior newsletters.
The 1980's saw a resurgence of interest in the musclecars of fifteen years prior, especially after the pathetic "performance" cars of the late 1970's. Many that were teenagers in the 1960's now had enough discretionary income to buy older cars, and they were doing just that as they began to experience nostalgia for "the good 'ol days". Auto makers were also beginning to explore the performance arena again in earnest, as they seemed to sense the public was ready for another round of muscular automobiles. The state of the art had advanced enough to allow vehicle makers to meet emissions requirements and still get their autos from point A to B quickly, and like gas prices, insurance cost didn't seem to many to be as much of a hurdle as it had been years before. And so a lot of baby boomers opted for both old and new musclecars in the garage. By the late 1980's then, the winged cars (as well as many other musclecars made by Chrysler, Ford, GM and AMC) began to again get the respect they deserved. This renewed interest peaked in the early 1990's, but remains high even today. Throughout this performance car re-birth of the 1980's, the core group of winged car enthusiasts continued to grow. Interest in all aspects of the winged cars was on the rise, including no doubt, the function of those mysterious scoops. And along with ideas evolving from within the winged car community, folks much less familiar with Chrysler performance cars must certainly have arrived at their own conclusions as to the scoops' function. More on some of these ideas in just a bit.
So what actually lead to the speculation about the function of the fender scoops and holes, be it among winged car enthusiasts or other people that knew very little about the cars? There certainly must be many reasons, but perhaps one of the most important springs from the rather unique nature of the fender scoops themselves. It was almost intuitively obvious, even to those with little knowledge of racing cars, that the wings and pointy noses on Daytonas and SuperBirds must have had something to do with the cars moving quickly through the air. So speculation about these pieces, even by the uninitiated, was apt to be pretty close to correct. And because the function of the noses and wings seemed pretty apparent to everyone, the amount of speculation remained at a minimum. The scoops however, had no intuitively clear function, even to those familiar with stock car racing. Nothing similar had been seen on street or racing stock cars up to that time, and without a clear frame of reference, people began a guessing game that had a lot of possible answers. Thus the proliferation of ideas about the scoops and their function. Let's take a closer look at some of those ideas now.Other Explanations
What is probably the most plausible alternate explanation about the mysterious scoops doesn't appear among those just presented. This theory concerns itself more with the holes under the scoops than the scoops themselves, and will certainly gain additional momentum because of an intriguing discovery made public here for the first time.
Regular visitors to the Aero Warriors site are familiar with Greg Kwiatkowski, as he has contributed a great deal of interesting and unusual material to the site. Greg's prototype Daytona wing and his recent find and purchase of the real #88 racing Daytona have been recounted here, and several documents and photos that Greg has collected over the years are also on display.
Because of Greg's enthusiasm for Chrysler products (as well as the fact that he works for them), Greg has had the opportunity to meet and speak with many of the people involved in the development of the Dodge Daytona and Plymouth SuperBird. And one of these encounters some time ago lead to a very interesting find about the cars' fender scoops!
In 1986, Greg was offered the opportunity to look through some old Chrysler paperwork belonging to Larry Rathgeb. Those familiar with the winged cars will remember that Larry was in charge of engineering for Chrysler's stock car racing program during the time that development work was being done on the cars. Greg made copies of much of Larry's rare documentation, including one piece of paper which is particularly significant to this discussion. The document has been recreated at left, and although it carries no date or identifying signature, it was found among documents that Larry told Greg he had authored during the Charger Daytona development. Look closely at the area shaded in purple.
The document seen here is pretty self explanatory. A Charger 500 (presumably a race prepared car) was used as a baseline for aerodynamic testing, with changes to the Charger 500 evaluated in relation to the drag produced when it was in the Charger 500 configuration. So, in the case of the first change to the car's configuration, the Charger 500 front end was apparently replaced with a long nose that included an optimum front spoiler set-up (whatever that was). The accompanying entry from the "Effect" column shows that this nose combination exhibited 9.5% less aerodynamic drag than the standard race Charger 500 front end. Several tests were obviously conducted, with the one most germane to this discussion shaded in purple. This particular entry concerns itself with the scoops (or "exhausters" as they are referred to here) and the aerodynamic advantage they afforded. As recorded in the "Effect" column, a 3% reduction in drag was noted when the exhausters were added to the baseline Charger 500 set-up! And of course this directly contradicts what Chrysler has been claiming about the scoops (exhausters) for the past 30 years.
Because there were no pictures or drawings included with the Rathgeb paperwork, some may question whether the exhausters mentioned were in any way similar to what actually ended up on the Daytonas and SuperBirds. And if they weren't, then perhaps "apples and oranges" are being compared here. If that really is the case then, this document still provides very important information. It discloses that Chrysler had some device, called an exhauster, that when mounted above the front tires reduced drag by 3%. And wouldn't it then be logical to conclude that Chrysler, knowing this, would not end up mounting something on the cars' front fenders that returned any less than this 3% drag reduction? So whether the exhausters mentioned in Larry's paperwork are similar to or very different from what eventually showed up on the cars, it seems reasonable to conclude that the exhausters actually found on the race cars yielded no less than a 3% drag reduction.
And yes, there is an assumption being made that the document presented here is genuine. It seems extremely unlikely that this document would have been created by Larry Rathgeb, Greg or anybody else in order to rewrite history on the scoops. For the purposes of this discussion, the document is accepted as genuine.How The Exhausters May Have Reduced Drag
Generally speaking, reducing air flow under racing vehicles will improve their performance. In the case of the winged cars, air flow under the vehicles caused drag because air collided with the aerodynamically "unclean" undersides. One result of this disruptive air flow under the cars was probably some degree of upward force being applied to the vehicles' bodies because of "trapped" air. Front spoilers, found on many racing automobiles including the Daytona and SuperBird, were designed to prevent or "spoil" much of the air flow underneath the cars. Yet another method to reduce air flow under stock car racers was to lower them, and that is where this particular explanation is rooted. The exhausters (or more correctly the holes in the fenders beneath them) provided a pathway for air to escape from under the cars, where it would otherwise be trapped as the autos moved at high speeds. With air trapped under the vehicles, their bodies would ride higher than with the exhausters, resting on this cushion of trapped air. And because the bodies were setting higher on this cushion of air, even more air could flow underneath them. Providing an escape path for this trapped air allowed the bodies to set lower than they otherwise would, and thus less drag was produced because of the reduced air flow under the cars.
And why were the exhauster scoops mounted over the fender holes? A vacuum would be created directly behind the trailing edge of the scoops as the air rushed by. This small vacuum may in fact have aided in air extraction from underneath the cars. Without the scoops, any vacuum effect over the tops of the fenders would probably have been much less pronounced, if not totally non-existent. This same principle is used in NASCAR's Winston Cup series today, as the exhaust headers are cut in such a way as to be flush with the rocker panels of the cars. The air rushing by helps "pull" the exhaust out of the headers.
Also note the name exhauster. Webster's Dictionary defines exhaust (including the noun form exhauster) as "to let out or draw off...to draw out the contents of...a conduit through which vaporous gases are emitted...an apparatus for drawing out noxious air or waste gases by means of a partial vacuum..." The name exhauster seems to support the contention that the scoop devices were in place to release something from somewhere, like air from underneath the front of the winged cars perhaps?Other Benefits
An additional benefit of the exhausters, and one unrelated to drag, is a reduction in ride height which in turn lowers the winged cars' center of gravity. And generally speaking, the lower the cars' center of gravity the better, especially as it relates to their ability to handle turns. Lessening air flow under the vehicles also allows greater control over the attitude or "rake" of the cars, as the bodies in some cases would probably have a tendency to be levered up by air flow while moving forward. By lessening total air flow under the cars, a more consistent rake angle could be maintained, which was especially critical for the winged cars.
As alluded to by Chrysler aerodynamicist Gary Romberg in two of the quotes above, the exhausters were the subject of speculation among Chrysler's racing competitors. To the extent that the exhausters distracted the competition and "psyched them out", they were also arguably of some benefit.
And it should be stated clearly somewhere in this article that the exhausters may well have provided tire clearance, although calling that their only function (or even their primary function) is what Greg's paperwork has called into question. It would certainly be ironic if the needed tire clearance was necessary only because of the reduction in ride height due to the functioning of the exhausters.Chrysler's Reaction?
What is Chrysler's reaction to Greg's discovery? He hasn't approached Chrysler engineers (past or present) en masse with the paperwork, although the few he has asked about it have had no response. If and when the opportunity presents itself, Greg will contact other engineers that worked on the cars to see what reaction they might have. If appropriate to do so, their responses will be reported here.
Greg Kwiatkowski's discovery of the air exhauster test results certainly provides ammunition for those that feel there is more to know about the "why's" of the fender scoops than Chrysler's tire clearance explanation. Whether the drag reduction benefit the exhausters offered has been a jealously guarded Chrysler secret for 30 years or just a small bit of data lost in the hectic environment of the cars' development and manufacture remains unclear. Hopefully someone from Chrysler will now step forward and help put Greg Kwiatkowski's discovery in perspective. But until then, the exhausters continue to be a bit of a mystery.
The author attended the 1999 Mopar Nationals in Columbus, Ohio and not surprisingly several of Chrysler's new and exotic offerings were on display, including several Dodge Vipers. The photos at left document an especially interesting aspect of both the street Viper (top) and its racing counterpart. Notice the louvered openings on the front fenders above the tires. They obviously aren't for tire clearance, as the closely spaced transverse louvers would impact the tires just as a solid fender would. Why these fender openings appear on some of Chrysler's contemporary high performance vehicles is certainly worth pondering. Perhaps the Internet District Court's indictment that introduced this article is closer to the truth than most realize!