Sooooo... What was the purpose of fender scoops...? ***VOTE in added Poll***

[69_500]

I'm 5x crazy as well. As long as  they let someone video tape it when its going on. I'd drive down with HD camera's in tow if they would allow it.

[xs29j8Bullitt]

I'm 5x crazy as well. As long as  they let someone video tape it when its going on. I'd drive down with HD camera's in tow if they would allow it.

'Tell you what... I will design and have printed an event T-Shirt and provide a FREE T-Shirt to all 5x "Penta-Crazy" contributors of $100 or more... any more takers?

Here is a T-Shirt that I did recently for myself...

[pettybird]

is this appropriate yet?

[xs29j8Bullitt]

is this appropriate yet?

No, not in the least...

[69_500]

I think that Allen just likes to draw pictures.

[xs29j8Bullitt]

Anonymous opinion poll added for the quiet types to express their thoughts... 

[maxwellwedge]

Anonymous opinion poll added for the quiet types to express their thoughts... 

And Mr. Anon didn't go first!   

[xs29j8Bullitt]

Anonymous opinion poll added for the quiet types to express their thoughts... 

And Mr. Anon didn't go first!   

Just getting over my shyness...    I'll go vote now!   

[Daytona Guy]

Can someone who thinks that the fender vents on the test mule are for tire clearance, explain to me how they can be effective for tire clearance?

Can someone explain to me, who use the tire rubbing the fender and HOOD as an argument for the fender scoops being used for tire clearance, why they made NO changes in the place where the tire rubbed the hood on the Daytona (don't see a partial hood scoop)?

If the opening in the fender where the scoop is for tire clearance why would they leave exposed sharp steel if that was true?

Why are they called "exhausters"?

Answers to good questions by those who believe in the tire clearance theory...

The exhausters are located directly over the tire because that is the most reasonable place for them. Too far forward it looses it's effect. To far back and it simply looks bad, and you end up getting too much air trapped to the back of the fender well before it can be extracted. They could have covered all the locations. do those look familiar? Notice where they start the first vent? Directly over the tire.

[Budnicks]

Just a question - does anyone know how much the race tires distorted at speed.  Sitting still, the tire clearly would not fit in the scoop but at 180 mph the top of the tire should be significantly narrower due to centripetal/centrifugal forces.  It should stretch the same way top fuel slicks do only not as dramatically.

"That was 1 of my thoughts exactly" , the tire is much narrower & taller at speeds & much more upwards movement/wheel travel under high speeds or hard breaking on corners even at shorter tracks with a bunch more caster & camber shown in any of the photos, I've seen on this thread, you would have to see the cars attitude at 200mph+ & cornering or hard breaking with caster & camber angles properly set with properly, style, sized rim & tires to give a real determination on what the drivers & engineers came up with & why they came up with it.... "On Race Car Only" Aerodynamics mainly, then "Pulling air out" from under the car sucking the car down to the track reducing wind drag & tire clearance was just an added bonus... IMHO

[C5X DAYTONA]

Can someone who thinks that the fender vents on the test mule are for tire clearance, explain to me how they can be effective for tire clearance?

Can someone explain to me, who use the tire rubbing the fender and HOOD as an argument for the fender scoops being used for tire clearance, why they made NO changes in the place where the tire rubbed the hood on the Daytona (don't see a partial hood scoop)?

If the opening in the fender where the scoop is for tire clearance why would they leave exposed sharp steel if that was true?

Why are they called "exhausters"?

Answers to good questions by those who believe in the tire clearance theory...

The exhausters are located directly over the tire because that is the most reasonable place for them. Too far forward it looses it's effect. To far back and it simply looks bad, and you end up getting too much air trapped to the back of the fender well before it can be extracted. They could have covered all the locations. do those look familiar? Notice where they start the first vent? Directly over the tire.

I am not going to argue with the Chrysler engineers that I and many others have talked to.  You can.  They say tire clearance.  (Safety) is first.    I can understand why.    I also know they are extractors.   I understand all the fuss but they said clearance and call them extractors.      Well except those in Doug's bed time stories..     Making room for a tire is simple.  Making it areo and other benefits takes extra work.  Maybe that is why it is called Extractor other than,  The Clearance Tire Thingies..  The original drawing of the Daytona that Pointer showed to McCurry doesn't even have (Extractors.)   :shruggy   Afterthought?  Did someone say to Pointer "You know we are going to need more room up top of the fender?"   He did design an extractor that fits over the race Daytona tire pretty well.  Looks to be more than an Extractor...   They knew they had a problem in late 68 with tire rub and they changed the torsion bar after a series of shock testing.   That fixed the problem.  They knew the Daytona (even before the first wind tunnel test) that there was going to be major down force on all 4 corners of the car.   Another thought.  Make the torsion bar stiffer?  At what cost?  Wheel bearings and spindles taking more of a beating?  More testing and someone here even said they have suspension bump stops..   Are you kidding?  At 200+MPH the last thing you want is the suspension hitting a bumper.)   That would be like hitting a wall for the control arm at that rate and speed the arm is moving.     Or just modify the production fender that was coming out in a few months?   I would choose the latter too.   Also, during those test engines are not running and tires are not spinning and (was the suspension is not loaded?)  But no big deal.   Wasn't the test mule a slow speed test car?  It's just a mock up car.  Also,  Why is the wing on the production and race Daytona so much higher than the mule?  More down force?  No!!  Trunk lid Clearance.  That darn word again...    The mule was just that..  A mule.   And I would defiantly call those one purpose air extractors on the mule. Not for clearance at all..  I also do call the vents on the production Daytona vents too.    My opinion is that when they took the car to the wind tunnel they thought they had made enough room and were interested in making areo and down force.   Also the Daytona didn't have near as much air going under the hood as the Charger 500 did.  The Daytona also has a huge spoiler under the nose in which it creates vacuum behind it.  So that high pressure issue under the hood was not as high as they had on the Charger 500.  Even with the Daytona traveling nearly 20mph faster.  The air was pushed out and even away from the tires with some spoiler set ups..  Very little air was allowed into the nose.  Just enough to keep it from overheating.  Which is even an issue on the street car due to the lack of air flow thought the radiator.    Obviously in some testing the tire even hit the hood, not near as hard as it would of hit the fender without that vent there.  We can throw in all our Degrees and racing knowledge but when more than one engineer says to me "believe it or not there for clearance 1st."  Well that is good enough for me.   I don't have a real race Daytona and extra millions to disprove them..  Or even care to question them to try to discredit them and think,   why did they lie?    Like I said.  I see both sides of the extractor, clearance issue.       I got to know George Wallace and even Bob McCurry quite well and I greatly enjoyed the many times I spent with them and the storys they told me.   So you can send over the FBI..     I am not changing my mind unless they say so..       Now I know there will be a post.  This turd is dumb and will not listen to reason.   I have bigger fish to fry.  Now,  when is the next track day??     If I typed something wrong or your pissed I will not change my mine..  Please,  just let it go..  Let it go.    Peace

[kab69440]

I'm 5x crazy as well. As long as  they let someone video tape it when its going on. I'd drive down with HD camera's in tow if they would allow it.

'Tell you what... I will design and have printed an event T-Shirt and provide a FREE T-Shirt to all 5x "Penta-Crazy" contributors of $100 or more... any more takers?

Here is a T-Shirt that I did recently for myself...

Yes. To whom do I PayPal/ mail the funds?

[xs29j8Bullitt]

The mule was just that..  A mule.   And I would defiantly call those one purpose air extractors on the mule. Not for clearance at all..  I also do call the vents on the production Daytona vents too.    My opinion is that when they took the car to the wind tunnel they thought they had made enough room and were interested in making areo and down force. 

I see both sides of the extractor, clearance issue.       I got to know George Wallace and even Bob McCurry quite well and I greatly enjoyed the many times I spent with them and the storys they told me.   So you can send over the FBI..     I am not changing my mind unless they say so..    

Sean, your opinion on this matter is very close to mine...  I voted for #4 on the poll (Aero design intent, minor tire clearance improvement with NASCAR mods).  Not having the correct racing parts on hand to evaluate makes analysis of the tire clearance issue very difficult.

You are very fortunate to have gotten to know the Chrysler employees involved in that era, and I have no intention of trying to discredit any of them.  My main interest in the subject is technical in nature, but I also have tired of the mocking and disrespectful way in which the subject is often discussed.  Your input on this has been clear, reasoned, and respectful... and I very much appreciate your participation in this thread.  

[xs29j8Bullitt]

I'm 5x crazy as well. As long as  they let someone video tape it when its going on. I'd drive down with HD camera's in tow if they would allow it.

'Tell you what... I will design and have printed an event T-Shirt and provide a FREE T-Shirt to all 5x "Penta-Crazy" contributors of $100 or more... any more takers?

Here is a T-Shirt that I did recently for myself...

Yes. To whom do I PayPal/ mail the funds?

  I guess Doug is just taking pledges at the moment... lets see what his plan is... 

[xs29j8Bullitt]

Here is my best guess at how the fender scoops may have helped tire clearance... not to scale sketch only...

[xs29j8Bullitt]

With reduced tire growth and less tire angle...

[pettybird]

You are very fortunate to have gotten to know the Chrysler employees involved in that era, and I have no intention of trying to discredit any of them.  

but...you...are.


why are you even beating this dead horse?  you asked if the INTENDED use for the scoops was clearance, and that's what the INTENDED use was.  like Sean said, go back to the mule.  it had poles for wing uprights.  they didn't know it would be helpful in turns to wrap them until it was done.  the INTENDED use for the uprights was to hold the horizontal stabilizer--the unintended happy side effect was that the wrapped uprights helped stability in corners. 

by questioning the INTENDED use for the scoops you most certainly are stating that you think the people we've met throughout many years and at many events are lying to us.  if you'd like to apply your knowledge of aerospace through the lens of 2011 knowledge, it's pretty interesting.  I encourage you wholeheartedly to continue telling us why our cars work--I love that stuff.  if, on the other hand, you continue to argue that a few guys that built rockets instead of race cars, working with pencils and slide rulers, manufacturing their own test equipment, using 1960's knowledge of aeronautics, knew something then which has NO VALUE kept as a secret, continuing their cover-up for reasons unknown...I don't even know how to finish the sentence.

[maxwellwedge]

I am just happy I have cars with the scoops on the fenders.....whatever their intended purpose.

[Aero426]

Allen's drawings are exactly the intended scenario that the Chrysler people have described.   However, the reality proven on the #88 was that with the angle of the tire, the inside of the tire HITS THE HOOD before anything else.   And that is with "Talladega suspension".      

The caveat the Chrysler people always added was that the fender scoops were added because of the problem on the '68 1/2 race car on an "if they were needed" basis.    In other words, they could not go back and add them after production.   So they did it, but then say, as it turned out the tire clearance to the fender wasn't a problem on the wing cars.

For many years, I was a true believer in the clearance function as Wallace, Rathgeb, Pointer, Romberg et al have described.     But when you look at it on the race car, it just becomes harder to believe.  

The 3% drag reduction statement.   Was it on the 3/8 scale tunnel cars, or was it proved out full scale?   Is it really relevant to the full scale car?   I don't know.   3% is a lot.   If you could give a modern Cup guy 3% aero improvement today, that would be HUGE.  

I do not believe that with the high air pressures being run, that tire growth was an issue.    They were not running wrinkle walls!

[Aero426]

I am just happy I have cars with the scoops on the fenders.....whatever their intended purpose.

+1

Let's all just have a big group hug now.  

[ACUDANUT]

I can't vote..You failed to add a vote block for Ventilation. 

[xs29j8Bullitt]

I can't vote..You failed to add a vote block for Ventilation. 

I had felt that ventilation / brake cooling / etc would be encompassed by air extraction / Aero improvements, but since you asked... your very words are now an option... now GO VOTE!     

[Daytona Guy]

The drawings below are not meant to be contentious – but are just to aid in the discovery process.

I hope that none of this gets people upset. People should be allowed to question and get answers. There are no accusations involved in any of the questions. There are no personal attacks on anyone. No one is lying here and there is no conspiracy. I have known engineer's from Ford (grads of Art Center College Deign) who were apart of teams that designed the Mustang. Teams build cars. Not everyone knows the reasoning for what another team member or group does. They may get told many things in the development process. Do we know the actual engineer who designed the fender scoop? There is no documentation that says the scoops are for tire clearance. This is the typical tension between physical evidence and witnesses. Sometimes they don't add up for many reasons. I have worked on my own car and can't remember why I did something (Smile).

I am coming to understand the tire clearance thing better from my own drawing and geometry from my car. I still have questions that would scare me to death driving if that tire traveled that far with sharp steel edges exposed. You don't cut wholes in fenders to fix one half of the equation.

All we have to do is see if someone who has a race Daytona to put a load on the top and jack in down to see where the tire would hit.

To me it is a part of life to question – even people's experiences – that is how things get tested and proven. There is nothing personal about it. I have no problem discovering I'm wrong about my questions. I just like the discovery process, but I also know some people don't.







My feelings are that the tire clearance was solved even under the heavier loads because there were no reports of it being a problem after that (68). We have facts that show air flow and improvements in aerodynamics are the reason for the scoops, and we have the infamous name "exhausters".  The test mule was the K & K car that hit 200 -  they would have had issues of rubbing if that was true. Do you test a car a low speeds to see if you're your high speed effects work?

M y point is that the scoops are for aero reasons. Secondary effects may have entered to picture and this is under question and can be proven true or false. Does anyone have the dimensions of the race suspension? Any parts measurements. This can be simulated.

Let's just enjoy this process; this does not need to be a bad thing.

Dane

[Daytona Guy]

I'm sure I'm not the only wingcar owner who's felt it, but at 100+ mph out of turn 2 going down the backstretch hitting 125mph, I could feel my car squating. I can ONLY imagine what the downforce is like at nearly 200 mph in a real race Daytona. The tire wearing/touching problem probably isn't as apparent at tracks like Bristol and Rockingham..

Yes, it is an amazing feeling. It is like someone is pushing down on the roof of your car. But in race setup, once you get the desired down force to stay in the corners, you make adjustments (camber, wing, front spoiler) so that it does not necessarily incrementally increase the faster you go.  What we experience at 100-125, the race cars may be dialed in to feel that at much higher speeds.  They were always battling the advantages and disadvantages of down force (then the need of more HP) and the aerodynamics of slipping through the air (giving more speed with same HP), yet loosing stability because it does not want to stay on the ground,  yet hoping to get a happy medium of both. I do get your point the Daytona had much greater down forces (that is what they were going for) than the 500. That does not mean necessarily that that the tires are going to rub. The answer is in the suspension because that did not fall under homologation rules. Also, a tire traveling that far makes for a lot of bounce and terrible handling. If it did rub, I would think that is not what you want from your suspension.

Another thought is the shocks – Can we look and see how far they would travel before they bottoms out. They look very short on top justing sitting still. Just a thought.

Dane


Dane

[hemiviper588]

I worked with Larry Rathgeb for many years on the Viper Project...he was our suspension development Engineer. I asked him the same question many years ago, and he said the scoop was there for tire clearance reasons only! I am sure they were hoping for an aero advantage, it just didn't happen.