2015 Aero Rules - Interpretations and Ideas

[paul_mh]

Hello, I am Paul from the TUG Racing Team and I am currently doing some concepts for a 2015 car and there are some things that are not really clear yet:

Firstly rule T9.3.1 b) says that

"In plan view, no part of any aerodynamic device, wing, undertray or splitter can be: Further forward than a vertical plane through the rearmost portion of the front face of the driver head restraint support, excluding any padding, set (if adjustable) in its fully rearward position (excluding undertrays)"

Now what is the rules commitees definition of "undertray"? Has someone already asked the rules committee about that? My personal definition would be: "An undertray is the aerodynimic surface that can be seen from the bottom of the car and lies between the bottom surface and XX,X mm from the ground. Parts of the sidepods or wings that can be seen from the bottom of the car are not considered parts of the undertray"

That being said I have already done a concept of a FSAE- version of a "wing car" like the Lotus 78 but I am not sure if this could be considered an "undertray" since this is essentially a big wing profile attached to the side of the car (altough there are sidepods on top of it) including some flaps at the end and in front of the rear tyres.
Also if you cut some slots into an undertray and generate "forward facing edges" by doing so you will have to round the edges and in the end this will look like an airfoil, but is it still considered part of the undertray?

Secondly rule T9.2.2:

"When viewed from the front of the vehicle, the part of the front wheels/tires that are more than 250
mm (9.8 inches) above ground level must be unobstructed by any part of the aerodynamic device, with
the exception of any vertical surfaces (end plates) less than 25 mm in thickness."

What is the definition of "vertical surface"? Can there be Gourney flaps or vents in the endplate as long as the whole part is less than 25mm thick? Or must the enplate be one flat part with a max. thickness of 25mm?

Thank you for answers :)

[Pat Clarke]

Paul,

You are not going to get a definitive answer, only opinions.
You need to direct your enquiry to the Rules verification site at whatever event you intend to attend,

Pat Clarke

[Kevin Hayward]

Paul,

I think there is enough clarification in T9.4 to allow the Lotus 78 style sidepods. The confusion comes from front and rear mounted devices without having clear definitions of where the rear and the front begin.

The titles give a clue to what each section T9.2 to T9.4. Unfortunately A3.9 states that the headings are only used to facilitate reading and do not affect the paragraph contents. Read objectively that means that T9.3 prohibits the use of any aerodynamic device forward of the headrest mounting front plane. No text in the paragraphs actually states that this is limited to the rear mounted aero devices.

I think the intent of the rule is reasonably clear, but as Pat mentions should be checked.

If you do have clarification from the RC please post the results here. What you are thinking about is likely being considered by many teams. I know the students at ECU have run the sims.

Kev

[JT A.]

Another good question is, "What is an aerodynamic device?". An argument could be made that anything that touches the airstream will affect the aerodynamics of the car, and could be used to improve the aerodynamic performance.

[JulianH]

JT has a point.

If I had to guess the intent of this rules, then an aerodynamic device is a part that has "the improvement of the aerodynamics of the car (e.g. reducing drag / increasing downforce) as one of it's key(!) functions. E.g. a wishbone affects the aero but it's main purpose is to link the wheel assembly with the chassis.

The keep-out zones prevent the positioning of "such devices". Therefore a tire, the upright and so on are "legal". An Aero-cover not.

The whole thing gets interessting if the wishbone (or a brake duct for example) is "aerodynamically shaped" to reduce drag. Then, in my opinion, it is an aerodynamic device and should be illegal because it is inside the keep-out-zone....

[Kevin Hayward]

Julian,

I would suggest an aerodynamic device (as suggested by the rules) is something that uses the flow, or pressure of air (external to the car) towards some designed goal. This would include, but not limited to:

- Brake ducts
- Radiators
- Intake system
- Wings
- Undertray
- Shaped body

Your example of the brake duct is a good one. It is very clearly designed to be an aerodynamic device, and as you say is in the keep out zone.

I think that what the RC intends is any device that is designed to produce a downwards force from relative air motion. The wheel pods throw a spanner in the works as they are primarily a drag reduction device (although they help keep temperature in the tyres). Unfortunately once you introduce devices involved with drag then the issues of aero section wishbone tube etc becomes problematic.

Kev

[Rory Hourihan]

It's my understanding that brake ducts would still be legal because they are on the inboard side of the tires. I'd also assume most teams wishbones lay below the max height rule and would also be legal. What I think is more of a blurred line is what the RC considers bodywork. There is a rule stating nothing to be above 19.8" between the wheels except bodywork. Is bodywork only something to separate the driver and the road? or can I place any item permanently affixed to my side panels to the car, between the two wheels, at any height I deem fit? so long as it isn't more than 15.75" outboard from the centerline of the car?

[mech5496]

Totally agree on the brake duct issue. As far as I understand it, you are allowed to put anyhing from 500mm upwards as long as it li withn of 400mm on each side of the car. For instance, I cannot see why you could not mount an 800mm wide sprint car style wing on top of your MRH as long as it is under 1200mm...

[Rory Hourihan]

I think there are some other rules that prevent that, something with driver egress and the new front vs. rear mounted confusion.

[mech5496]

Not sure... I mean yes, driver egress would be tricky but I cannot find anything that excludes it. Or a bi-pnae front wing with the upper plane above 500mm...

[John_Burford]

My opinion would be to look at the Primary Function of the component

- Brake ducts: For cooling brakes; not an aero device
- Radiators: For cooling engine; not an aero device
- Intake system: For engine combustion; not an aero device
- Wings: For downforce and grip; is an aero device
- Undertray: For downforce and grip; is an aero device
- Shaped body: For protection from debris and aesthetics; not an aero device

John Burford

[jipi2084]

I think the aero rules should state : "No part of the car" instead of "no aero device".

No team need to put anything over the tires or less than 75mm from them. Same thing for the front and rear distance from tires and the sidepods height.
Right now a lot of rules are stating the same thing or almost the same, like the rear wing width and the open wheel rule. This create a lot of confusion in the teams and will for sure create a good amount of team using loopholes and more complications during tech.

As for brake duct, John state that the primary function is brake cooling. If I designed a brake duct it would be to fill the wheel opening and clean the flow for the radiator ... brake cooling would be a secondary function ...

Changing to no part of the car would leave no interpretation and thus less frustration from the teams in my opinion.

[Z]

My opinion would be to look at the Primary Function of the component

- Brake ducts: For cooling brakes; not an aero device
- Radiators: For cooling engine; not an aero device
- Intake system: For engine combustion; not an aero device
- Wings: For downforce and grip; is an aero device
- Undertray: For downforce and grip; is an aero device
- Shaped body: For protection from debris and aesthetics; not an aero device

John,

You are defending the indefensible. Or else you want the following to happen.

Student - "But ... we've shaped the body primarily for 'protection from debris, and aesthetics'..."

Official - "No you haven't! How dare you disagree with me! In my opinion you are exploiting a loophole in the Rules to unfairly generate downforce. That is a complete contravention to the INTENT of the Rules. Aaargh..., you C&I types make me sick!!!"

Student - "But the bodywork doesn't generate ANY downforce at all. We've tested it. It does reduce drag quite a lot though, which is good for Fuel Efficiency. And the very few times that any Officials have commented on this in the past, they have, sort of vaguely and UNofficially, suggested that 'aero devices' are things intended for 'downforce and grip'..."

Official - "That's it! YOU ARE OUT OF THE COMPETITION!!!"

Official storms off mumbling to self - "These students have to learn that this competition has got nothing to do with good Engineering. It is all about learning how to kowtow to your superiors..., which in this case is me!!!"
~o0o~

The current Rules Committee members are INCOMPETENT BUFFOONS.

These latest Rules changes are a disgraceful example of Engineering documentation. They are most certainly NOT a good role model for the students to follow. No clear definitions. Pathetic drawings. Far too many words that clarify nothing, but add untold ambiguity.

This Rules Committee is accelerating society's descent into Idiocracy. I suspect they are doing so for the selfish goal of covering up for their own personal IDIOCY.

The inmates have taken over the lunatic asylum.

And you, John, are supporting them.

Z

[Bemo]

Normally I tend to defend people working for FSAE voluntarily, but after having read the new aero rules thouroughly, I can only say that these new rules are a shame for any engineer. I don't care so much about what should be allowed or not allowed. What bothers me is that as many stated before, it is not properly defined what is allowed and what is not.

The rules talk about "aerodynamic devices" all the time without even trying to give an idea what is considered to be an aerodynamic device to just mention one of the most obvious problems. While having a look at the "drawings" I had the impression that this might be first concept sketches. I cannot believe it got published like that. If a team dared to have pictures of that quality in their design report, the judges would give them a very hard time.

The whole section T9 is a shame for engineering. I can't believe someone with an engineering degree can be willing to publish such a bad and unfinished work. How can teams be supposed to respect the organisers while the official documents which the competition is based on are executed in such a bad manner???

PS: This is my sole opinion, I cannot speak for any organisations or competitions I am involved with.

[Rory Hourihan]

Ive submitted a rules clarification for a definition of "Aerodynamic Device" and "Bodywork" as well as clarification on rule T9.4.2 as it pertains to a design I've got. So we'll see what sort of definitions I get back.

[mech5496]

Rory, could you please post them here as long as you hear from the RC?

[DougMilliken]

... The inmates have taken over the lunatic asylum.
Off topic, but along these lines, I can highly recommend "The King of Hearts".
Currently available here, https://www.youtube.com/watch?v=DGEqDF6ZMyY
There is a short "skid pad" scene at about 55 minutes...<grin>

[apalrd]

It would be nice if the RC answered rules questions promptly, too, since there are so many issues that the rules require so many questions.

This year, I have so far submitted 4 questions and emailed a 7-page proposal to Kaley, one was answered (they basically said to completely ignore the IC voltage rule with respect to charging systems), and one was answered and re-opened, leaving three questions which haven't been touched in over 2 weeks and no response to the proposal from over a month ago.

[mech5496]

http://static.squarespace.com/static/54073934e4b00b0594c179de/t/54550023e4b02058e33068b8/1414856740638/?format=1000w

I will leave this here...

[Rory Hourihan]

The rear wing looks to be a little high, but I don't really have any reference frame. Also the gurney flaps on the front wing endplates seem to be above the 9.8". I'm enjoying the front wing though, this is what I expected from most teams.

[mech5496]

Endplates and gurneys are allowed even higher that the 9.8" mark, if they are narrower than an inch. On the rear wing it seems like the highest point is 3.5 times the wheel diameter above ground. Given that those are 10" Hoosiers most likely (around 18" OD), the height seems reasonable. I will aggree with you on the front wing, I expect to see a lot of this.

[Rory Hourihan]

I've got a little confusion on this and i'd like to hear how some others are interpreting these rules.

Rule T9.4.2 allows aerodynamic devices up to 19.7" from the ground between the front and rear axle center-lines. Rule T9.3.2 and T9.3.1 allow rear mounted aerodynamic devices up to 1.2m from the ground between 9.8" aft of the rear tire and up to the headrest. The confusion is the area of overlap between the rear axle center-line and the headrest where it sounds like it is legal and illegal to have aerodynamic devices (rear wing and ducting?) above 19.7" and below 1.2m... or is this covered by the part of the rule T9.4.2 that states "except as permitted under T9.3.1" even though rule T9.3.1 doesn't reference height from the ground? Sorry if the attached photo is a little dim.

[Bemo]

This is exactly how I would interpret this rule, although its wording is awefully complicated and the pictures don't really help as they are executed extremely bad and are not explained :(

[MCoach]

To be fair, in the rules they only really give a box for the Rear wing.

The front wing only has a boundary of no wider than the tires, and no further forward than ~27 inches. Nothing says how far back the front wing can legally stretch. There are some keep out areas, but nothing truly defining like the rear wing.

[Swiftus]

...Nothing says how far back the front wing can legally stretch...

I give you the first Kettering aero car!

418

Hehehe. Could be good.

[acedeuce802]

How did you get a hold of our 2015 concept drawing?!?!

:P

[Rory Hourihan]

That is true... nothing says you cant make your rear wing a "front mounted device".. although maybe they'd get you on A3.6.

[MCoach]

That's a very flattering picture, Jay. :)

Rory, that's what rules questions are for. We already have a collection of "take a copy of this to tech inspection, and it's legal" rulings.
I'm pretty sure that this wouldn't fly like the picture, and I wouldn't push it that far, but you could say that your front mounted diffuser extends to the rear of the car....you could probably get away with that much.

--and is part of your "front" wing which is integrated into the diffuser and extends back as far as you desire, behind your rear wing. That would probably put some panties in a twist.
Could be legal as long as it's still "front mounted", I'll let you guys explore that rabbit hole.

[SloBroski]

424 ;00000000000000000000000000

[Rory Hourihan]

Is that underbody running under the front wing main? I'd be curious to know where the COP is in that configuration.

[SloBroski]

shhh its a secret ;) You'll find out when it's on the car!

[MCoach]

Needs more Hello Kitty wing.

[paul_mh]

Hello everybody

I have now finally received all answers to my rules questions from both the FSAE and FSG rules commitee and I want to share these answers with you:

Regarding the question what a "vertical surface" should be that can be used above 250mm in front mounted devices I got a clear answer from FSAE:

"The intent of T9.2.2 is to maintain the open wheel appearance of the vehicles from all directions, and as such the intent is to allow only devices that lie in X-Z planes with a maximum dimension in Y of 25mm. This does not preclude the use of gurney flaps on the end-plates, vortex generators, etc that fall within the allowable dimensions. We will consider revising the wording to clarify in the next rules revision cycle."

Regarding the exception for "undertrays" in rule T9.3.1 b) for the for and aft positon I got 2 answers (to clarify what is the definiton of "undertray")

from FSG: "In the FIA Technical Regulations the underbody or undertray surfaces are called “Bodywork facing the ground”, and there is no term ‘diffuser’ or ‘wing’ mentioned in the rules. Therefor FSG will fellow this definition"

from FSAE: First I got a very unclear answer saying that only a flat floor would be allowed in front of the plane of the head restraint but after another long wait I finally got the answer that "Yes, 'the area between the wheels is completely free (up to a height of 500mm from the ground), so you could use any kind of aerodynamic device here, as long as you stay clear of the 75mm from the wheel' in a top-view." Which means that FSAE basically allows all kinds of aerodynamic devices as long as they are within the allowed areas defined by the "green boxes".

Hope this helps any of you guys, and I am sorry it took so long but the rules commitees were not very fast :/