90 degree spoiler vs 45 degrees

[turbogrill]

Hi,
I know nothing about aero and have never driven an aero car, but I do see a lot of fast cars with aero.

I don't have points for wing but I could build a 5inch spoiler that would almost be 90 degree but most spoilers I see are 45 degrees.

This would be for a Miata and the track are mostly low speeds. (but lots of aero cars on those races)

Thoughts? The spoiler would be made from some hardplastic trim that sits on the side of the car.

Also I assume any fasteners would be 0 points, this would be some angle bracket or something.

 

Edited December 4, 2022 by turbogrill

[jakks]

Too much drag. 
 

Have you done the calculations on how many laps in an 8 hour race would 1 second a lap faster be on this “low speed” track is? 
 

On a 1:30 lap track with no aero, paying 10 points and a lap is well worth it. 

[LuckyKid]

There are too many variables, but assuming there is SOME attachment, the max would be 90 degrees to the air, which should be about 70 degrees to the car:  http://2.bp.blogspot.com/_jdXbEFeA6Ek/TTfsfOmwgWI/AAAAAAAAAh8/9qthkVIp06k/s1600/Wind_Tunnel_MX5_NC_1.jpg

I would recommend building something to try different angles.  

In my testing on the NA, the 3-4" spoiler was worth maybe 40-60% the DF of the 9LR wing at 0 degrees,  but results were inconclusive as far as drag and anything definitive with the exception that diffuser and spoiler only was not enough to balance the splitter at Road America. 

[turbogrill]

I could try and test it, so many other higher priorities!

 

What about in the rain, I would think and rear DF is beneficial regardless of drag given that corner speeds in rain are ridiculously low?

[LuckyKid]

1 hour ago, turbogrill said:

I could try and test it, so many other higher priorities!

 

What about in the rain, I would think and rear DF is beneficial regardless of drag given that corner speeds in rain are ridiculously low?

You should be able to make a spoiler with zero points, there are plenty of things that can be used.  We used some cut bumper and the support structure from the hood.  For rain, absolutely run the highest DF setup.   

Each track has its own key sections where you need the car to feel stable, and are able to drive consistently and confidently through those sections. 
Road Atlanta - 4, 11
Road America - 1, 7, and Carousel
Watkins Glen -   5, 6, 10
Sebring - 1, 14
NCM - 5, 16
VIR - 10, 11

I like to set my downforce right at the limit where I feel comfortable and trim everything out.  Its possible that it would be faster with more downforce, but I feel this gives me confidence and the balance I need with the car, otherwise I feel I am not only too draggy, but also too pushy. 
 

[MMiskoe]

Aren't spoiler's 10points?  Seems pretty clearly called out, but maybe my interpretation is different.

[turbogrill]

3 hours ago, LuckyKid said:

You should be able to make a spoiler with zero points, there are plenty of things that can be used.  We used some cut bumper and the support structure from the hood.  For rain, absolutely run the highest DF setup.   

Each track has its own key sections where you need the car to feel stable, and are able to drive consistently and confidently through those sections. 
Road Atlanta - 4, 11
Road America - 1, 7, and Carousel
Watkins Glen -   5, 6, 10
Sebring - 1, 14
NCM - 5, 16
VIR - 10, 11

I like to set my downforce right at the limit where I feel comfortable and trim everything out.  Its possible that it would be faster with more downforce, but I feel this gives me confidence and the balance I need with the car, otherwise I feel I am not only too draggy, but also too pushy. 
 

That is some cool data!

What about height of the spoiler, a few inches?

[turbogrill]

57 minutes ago, MMiskoe said:

Aren't spoiler's 10points?  Seems pretty clearly called out, but maybe my interpretation is different.

You are allowed to remove material for 0pts, repurpose material for 0pts., adding material is points. Sometimes adding material and the fixed item list becomes the same thing, then I think the fixed item list takes precedence (for instance a wing is 10pts even if you manage to build it in wood for 5 pts).

The only exception is camshafts, if you grind off material from a camshaft it's still points. But you can shave the head, port the intake, build a wing from the dash, splitter from the sunroof, larger TB from the ashtray etc,etc,etc,etc...

I am not sure if you can claim material for aftermarket pistons, the material is also measured in area units not volume so not sure how that would work.

[LuckyKid]

10 hours ago, turbogrill said:

That is some cool data!

What about height of the spoiler, a few inches?

I don't have any data on that unfortunately.  Without wind tunnel testing, you need to track test to find out what really works.  

[turbogrill]

From internet, so it must be true:

I don't want to have the drag of a full sized track in my miata...

Some interesting reading, https://www.team-bhp.com/forum/technical-stuff/224530-aerodynamics-simulations-tesla-model-s.html

On the Tesla a tiny lip rear spoiler seems to slightly reduce drag and add a good amount of downforce. 

Different car but still!
 

Edited December 5, 2022 by turbogrill

[LuckyKid]

23 minutes ago, turbogrill said:

From internet, so it must be true:

I don't want to have the drag of a full sized track in my miata...

 

Here is some actual windtunnel info and you can compare that to what Johnny says.  I think both are C6s?

 

https://www.corvetteforum.com/forums/attachments/autocrossing-and-roadracing/48315954d1616390310-anything-to-gain-from-sideskirts-on-c5-katech-wind-tunnel-data-report.pdf

 

 

Looks like the CFD he has is a big spoiler.  None the less, both add drag.

[Throoster]

8 hours ago, MMiskoe said:

Aren't spoiler's 10points?  Seems pretty clearly called out, but maybe my interpretation is different.

Champcar does not have a similar rule to "...A. Other than when necessary for safety enhancements, an authorized addition, modification, substitution or removal may not perform a prohibited function ..."

 

And without an order of operations spelled out it may be open to interpretation. Fixed points schedule say 10 points but "4.7 OTHER EQUIPMENT THAT DOES NOT COUNT TOWARD THE TOTAL POINT VALUE" says you can repurpose parts/material for free.  Which takes precedent? 

 

I know what the traditional interpretation has been (all repurposed stuff is free), but an argument can be made that even if repurposed parts/material are used, if they perform a function that is called out in the fixed parts schedule they are charged the points.

[mcoppola]

A bit of history here. A few years back, the TAC group proposed that even if re-purposed materials were used to make something on the Fixed Point List, the fixed point rule would take precedence. That rule was in effect for 1 race, where someone showed up with their decklid flipped over to create a spoiler. The CEO and BoD at the time quickly threw that short lived rule out the window because the reasoning was that it was cool and creative to do what said team did.  

[MMiskoe]

So I can remove the hood and use that material for some other purpose (its 39% of the bodywork area).  Since it is just repurposed material can I the mount that reposed material anywhere on the car?

[turbogrill]

1 minute ago, MMiskoe said:

So I can remove the hood and use that material for some other purpose (its 39% of the bodywork area).  Since it is just repurposed material can I the mount that reposed material anywhere on the car?

thats what they say!

BUT I am skeptical to that it will continue, the problem is the fixed point list vs reused material. 

I could give my hood to fabricator and pay him $4000 to make a wing out of it.....

[Wheelman_99 - C Rallo]

Plus one for more than 45 and less than 90.

 

 

Edited December 6, 2022 by Wheelman_99 - C Rallo

[Throoster]

11 hours ago, mcoppola said:

A bit of history here. A few years back, the TAC group proposed that even if re-purposed materials were used to make something on the Fixed Point List, the fixed point rule would take precedence. That rule was in effect for 1 race, where someone showed up with their decklid flipped over to create a spoiler. The CEO and BoD at the time quickly threw that short lived rule out the window because the reasoning was that it was cool and creative to do what said team did.  (Emphasis added)

I seem to remember this, but could not document it, so I did not bring it up. It seems like the TAC group got it further than a proposal if it was a rule for one race and was then thrown out.  Maybe it is time to revist that, AND maybe time to revist ALL the decisions made just because stuff was "cool and creative", but not necessarily within the rules....

Edited December 7, 2022 by Throoster
spelling/grammer