Side fences......Is it legal?

[Allan T. Chou]

Attempting to figure out a better way to attach the rear diaper on my Reynard FF82. The assembled tail has no NACA profile so I was thinking if I mounted an aluminum plate onto the upper body and secured it with Dzus fasteners on the lower diaper, it would give me a solid and quick removal mounting system. Outside of cleanintg up the lines and providing a more secure mounting, I can't see any aero advantage. But Is this legal? Thanks Allan

[steve zemke]

You may want to draw it up and submit it to Topeka for a review. I would be asking the national technical office.

[Art Smith]

Allan-

what paragraph, section, phrase in the GCR as currently written are you worried about??

I for one can't imagine how a reasonable person could conclude a vertical piece of sheet metal is a "wing" or "other airfoil device" let alone something that creates downforce (GCR requires both concurrently). the most basic physics doesn't support the conclusion. wings are devices that create lift efficiently through pressure differences on their top and bottom surfaces. any reasonable person test for a the definition of a wing must include the word efficiently since even pigs can be made to create lift with enough speed and angle of attack. doubters should dig out their VCR tapes of Rusty Wallace or Elliot Sadler flying backward at Talladega in large pigs; there's no wings or other airfoil devices on those hogs. vertical pieces of sheetmeal / endplates / fences are drag reduction devices. they are extremely effective at killing tip vortices (and their associated drag), preventing the mixing of dirty turbulent air with undesturbed / well behaved flow, and managing regions of both high and low pressure.

first day out to the track I'd recommend taping (scotch tape does great) some yarn on your endplates to see if they are tall enough. if they're tall enough all the yarn will be parallel to the direction of travel and there will be NO yarn curled over / around the top or bottom. depending on your car's track and the width of your body, you might see artifacts of the rear tire wakes on your endplates......................

Art
artesmith@earthlink.net

[Allan T. Chou]

Hi Art

Thanks for the input, I fully agree, for this application there is absolutely no areo benefit, nor was I going for any. Although on my Sports 2000, the fences do create significant downforce by using the entire top of the body as a dive plane. I just didn't want to dice with a scrutineer next year. The original 82 Reynard had that truncated tail (as pictured above) with longer and no tail (Torpedo body) versions in 83 and 84. But I did recall a rule that the body could not extend beyond a certain dimension from the centerline of the rear axle. Or was that for F2000? Anyway I will assume that this mod complies with all rules unless otherwise advised. Thanks again Allan

[Art Smith]

Allan-

it's extremely important to understand that vertical fences DO NOT and CAN NOT create downforce!!! in one of their applications, used correctly, they can help to manage regions of high and low pressure created via some other mechanism. regions of high and low pressure can create downforce; fences can ony manage existing regions of high and low pressure.

I'm guessing if you check your current copy of the GCR or the online copy you'll find bodywork is limitted to 39" or less behind the rear axle line.

Art
artesmith@earthlink.net

[Larry]

I'm in agreement with Art. Too many folks equate drag reduction with downforce. Most bodywork is there to reduce drag. You can use it to manage airflow, too. Drag reduction is not prohibited by the GCR (good thing, as it would be impossible to regulate). Airfoils are different. Fences are not airfoils.

I worked for an aircraft manufacturer that led the way in the use of "winglets," or what we would call wing endplates. The purpose of these was to control airflow by keeping the low pressure area on the top of the wing from sucking up the high pressure area from beneath the wing at the outboard tip. It was common for the outer 2' of wing to lose effectiveness due to the vortex that would swirl in this area. By using a winglet, we calculated a 2%reduction in drag.

Larry Oliver
International Racing Products

[Roland V. Johnson]

Call the national office and ask for a copy of Court of Appeals Ref No 95-055-NP, or I can fax it to you. Anything that is added onto FF bodywork with the intention of creating aerodynamic downthrust, that is not specifically allowed by the rules(ie a rear spoiler), is not legal.

[Tom Irwin]

Roland,

Fax> 818-768-4999

thanx

[John Robinson II]

Roland, do you by chance have any history on the diffuser/undertray ruling? I have heard from RP and talked to larue and have a better understanding of what should be legal, just looking for documentation to back it up.

Thanks,
John

[Purple Frog]

Must be legal...

[John Robinson II]

Froggie, what session was that from, it did not look like that in post race impound

John

[Art Smith]

the "answer" on bodywork shown in The Frog's picture is almost surely related to the question(s) asked. what feature(s) of the bodywork shown in the picture were alledged to be non-compliant with what paragraph(s), section(s), phrase(s) in the GCR as currently written.

while there's several very interesting aerodynamic features in the picture, it's my sense it will take more than a single protest at the RunOffs to clarify what is compliant and what is not compliant with the bodywork language currently in the GCR; it's not objectively verifiable!! terms have to be defined and thresholds of performance established to deal with the reality of the physics. lots of things can be made to create lift; that doesn't make them all wings. air expanding around the bottom surface of a Hewland mk-9 transaxle is diffused; does that make the mk-9 a diffuser? an objectively verifiable definition for diffuser (among other words and phrases) is deperately needed. and like the criteria established in the definition of stressed panels, thresholds absolutely must be established to deal with the non-black/white nature of the physics being regulated. air is diffused at the rear edge of a perfectly flat and horizontal FF bellypan; does that make a flat bellypan non-compliant with the diffuser undertray language..........?


Art
artesmith@earthlink.net

[Art Smith]

the picture was originally posted on ApexSpeed on Wednesday, October 9 at 12:23pm.

Art
artesmith@earthlink.net

[Purple Frog]

JR,
Art got it correct. It was one of the qualifying sessions. I was a bit busy before the race with somebody's two sets of optional race tires to be taking pictures. I walked past and saw that it appeared to be more trimmed in its vertical dimension for the race.

I took the picture not to say anything was wrong, just to show Apexspeed what one of the discussion topics was. Just like the picture of Kephart's wheel whatzits that were not wheel covers.

I figured Apexspeed readers knew what a towel looked like, so I saw no need for photographing "temporary bodywork".

[Roland V. Johnson]

Tom, did you get the fax? John, I'll try to answer your question later, or give me a call.

[formulasuper]

"Thanks for the input, I fully agree, for this application there is absolutely no areo benefit, nor was I going for any."

Allen, You're using the term "aero benefit" incorrectly. The standard meaning of aerodynamic benefit or aero advantage includes reducing drag. Therefore this application does have aero benefit. Down force is just one part of aerodynamics. I'm sure you know this but I'm just trying to clarify this for the many readers who may get confused on this subject.
Standard disclaimer: Did the Holiday Inn Express thing, once.

[Gerald Barrett]

I would guess the Frogs pic was taken Tuesday. That is how it looked in impound Tuesday after the Qaulifying session. When the court explained their ruling to me, they said there was not a tunnel on the rear lower panel when they looked at it. They implied that many witnesses saw a tunnel earlier in the week, therefore the protest was well founded.
They also implied they would really like to know if a tunnel shows up again on the rear panel of that car.
Tony went faster without it, so I doubt a tunnel will ever be on the rear of that car again.

[Tom Irwin]

Roland,
I just checked the office and to my glee, I'll have some reading to do.
As you know I'm a bodywork kook, an aero geek, somtimes naked.

I do like to experiment with FF aero. And the constraints are always a challange.
I do not or condone "cheat" but I make it my personal best to make em' faster.

Thank you

[Allan T. Chou]

Thanks for hijacking my thread Tom lol. BTW I'll be in LA LA land on 12/10 for the week and Vegas the weekend before. Let's try to hook up for dinner or something. Please don't come naked, Allan

[S Lathrop]

The rules dealing with ground effects/down force devices in FF needs a complete rewrite. I can write protests that would make every FF at the run offs questionable for legality. In particular all the players in the FF game have some part of the body licked by the airstream that could be ruled illegal.

Every so often we get some officious official who wants to raise hell by imposing his interpertation on the rules. FF this year was one of the victums.

An old friend once told me that each class gets the rules they, the class participants, want. FV has been very active about protecting thier rules from outside antigonists. FF should do the same. The FF competitors need to take charge of their class and the rules.

I look at the photo of TC car and I can see how it can be protested but if you fought that issue all the way through the protest and appeal process, I am not sure it is not legal. What is a venturi or diffuser under tray? Do the vertical outer edges make it illegal? it meets the 1 inch deviation rule. Show me the rule it violates and exactly what part violates that rule.

The rule was changed after a protect against a car that I built. My car was illegal but no one on the tech committee or stewards understood the rules well enough to see what was wrong. Instead Tte comp board wrote an even worse rule. The funny thing was I offered to explain what was illegal about the car that they wanted to find illegal.

We need to get sanity in the rules. Oseth's car had a front splitter as do all DB1 Swifts. But the Piper was illegal because the structure was not disguised correctly? And the competitors let the techies cow them into changing their cars? The FF competitors need to get the rules cleaned up.

[andyllc]

I hadn't noticed the picture of Coellos 'diffuser' until today. How is that any different from what Gelles ran several years ago (01, 02 range I think)?

[Tom Irwin]

I also spent a long time typing the transcript of the FAX Roland sent me and it got lost in hyperspace. Drat!

I was all set to retype it when I got home tonite and I left it on my desk at work. Double Drat!

Some of my good racing friends are going to be surprised at how the COA ruled in the bodywork/side fence thingy. I know I was.

I hope I get a chance to post it from work tomorrow

[Larry]

Can someone either post the COA ruling or provide a link to it?

Thanks,
Larry Oliver
International Racing Products

[Tom Irwin]

I have left the name/s of the party invoved because I have not contacted them for their permission. If you have any questions you might give Roland a call.

I've cut to the chase and omited the whole document, to save time and typing at work.

SCCA COA Report Nov. 10, 1995 Ref. No. 95-055-NP

Rulings of the Court

The court is concerned, based upon Mr. _________ protest and the decision of the SOM, that airfoils and other aerodynamic devices will continue to proliferate a class that is significantly restricted in these areas under the rules. Each and every example Mr. _______ submitted violated these rules in one or more areas. Theses included adjustable airfoils (D.13.6.8.A.5.). Wings and other airfoil devices which have principle effect of creating aerodynamic down-thrust i.e. add on fences or wing end plates, forward facing gaps or openings in the bodywork or spoilers in the form of raised end plates continuous with the body surface but wider than the body work. (D.13.0.6.8.B.)

Competitors participating in restricted classes should be very conversant with the rules under which they are competing. Extreme deviations of these rules could be interpreted as willful non-compliance with the rules.

Mr. _________ Appeal is considered well founded and his appeal fee less the amount retained by the
SCCA shall be returned to him.

CC
Dick Temleton
Larry Albedi
Rodger Eandi
Bill Dwyer
Vivian Stegall
(___________)
Driver File
__________________________________________________ _______________________________

I want to thank Roland Johnson for his time to send me this.
Roland has been in this sport for a long time and is very well respected for his talents and skills with Formula Fords

[Roland V. Johnson]

Tom, feel free to post the appeal itself. The decision doesn't make that much sense without it. It's much too long for me to type again after all these years. Larry, if you want, I'll fax it to you.

[Roland V. Johnson]

Pictures refered to in appeal. (I hope)