INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

Racing car aerodynamic optimization

RE: Racing car aerodynamic optimization

Fastest cheapest aero thing that comes to mind is a fairing over each pair of tubes supporting the rear wing.

Mike Halloran
Pembroke Pines, FL, USA

RE: Racing car aerodynamic optimization

more down force ? more incidence for the rear wing, bigger rear wing, more elements to the rear wing (like F1). what's the undertray look like (how well controlled is the outlet ?)

like greg says, how do your class rules limit things ?

Quando Omni Flunkus Moritati

RE: Racing car aerodynamic optimization

(OP)
Thanks for answers,

Greg Locock - I certainly do not narrower tires !!! smile
I have not any class rules limitations


MikeHalloran - what exactly do you mean ?"fairing over each pair of tubes supporting the rear wing"
closed profile support?



rb1957- rear Wing is two element with gurney flap,
undertray is flat aluminum plate begins under transmission and ends under the rear axle axis



Radek

RE: Racing car aerodynamic optimization

What I mean is, there is some parasitic drag associated with each of the support tubes on each side of the car, because they are (apparently) round, and because there are two of them. The after tube just has to interfere with the vortex street trailing behind the forward tube.

So, fold a pizza box in half, slap it over both tubes, and staple the loose ends behind the tubes, so you end up with a sorta streamlined 'pant' over the two tubes.

At least put a streamline sleeve over each tube.


Also, the plate that attaches the tubes to the wing and the flap; that's aero-ugly, and probably bigger than it needs to be structurally.

Mike Halloran
Pembroke Pines, FL, USA

RE: Racing car aerodynamic optimization

(OP)
OK Mike,
I understand now dazed

RE: Racing car aerodynamic optimization

Additionally, the forward tube could be smaller in diameter (and not stressed in bending) if you added a third tube extending toward the forward end of the decklid, so you end up with a structure looking like the letter 'N', and fully triangulated. Skin the whole thing of course.


Also, the secondary airfoil is not strictly a Gurney flap.
http://en.wikipedia.org/wiki/Gurney_flap

It might be more effective as a downforce device if moved up a little so it's out of the primary foil's boundary layer but still in the pressurized area.



Mike Halloran
Pembroke Pines, FL, USA

RE: Racing car aerodynamic optimization

i'd just cover the space between the tubes (rather than fairing each one).

is the undertray vibrating any ? i hear that F1 gains alot in the careful management of the airflow under the car.

how about a 3rd rear wing element ?

Quando Omni Flunkus Moritati

RE: Racing car aerodynamic optimization

there might be a little drag reduction fairing the front bumper edge and maybe fairing the front of the engine bay (the hood fwd edge, yes?)

Quando Omni Flunkus Moritati

RE: Racing car aerodynamic optimization

(OP)
rb1957 - ???? fairing the front bumper edge and maybe fairing the front of the engine bay -the hood fwd edge
I do not understand


Here small gurney flap:

RE: Racing car aerodynamic optimization

front bumper ... the top edge looks pretty sharp (in your first pic) ... consider adding a radius block (to fair in the edge) ... it might reduce drag (a very little).

hood fwd edge ... again, your first pic shows the fwd edge of the hood, doesn't look smoothly faired into the front panel (in front of the radiator).

i understand two elements in the rear wing ... why not three ? (like F1)

Quando Omni Flunkus Moritati

RE: Racing car aerodynamic optimization

(OP)
I could replaced rear wing tubes vertical support plates
yes,
probable vibration is seen at the first image
(undertray bend before the rear wheel)


is a replaceable curtain for reducing pressure under the hood (entry restrictions cooler)
look what hood does (lift) without curtain

https://scontent-b-vie.xx.fbcdn.net/hphotos-ash4/9...

RE: Racing car aerodynamic optimization

(OP)
Of course, I can give big rear wing or 3nd wing element.
But how do you reach more downforce on the front end for aerodynymic balance?

Thanks for Your any more ideas

RE: Racing car aerodynamic optimization

Downforce on the front?
Jack up the after end of the hood, like the car told you it wants, or just truncate the after end, leaving a big slot for the air to get out.

Maybe you can take it far enough to turn the hood into a huge front wing.

Mike Halloran
Pembroke Pines, FL, USA

RE: Racing car aerodynamic optimization

(OP)
Mike,
You can to specify?
just to make sure that I understand correctly.

RE: Racing car aerodynamic optimization

Instead of trying to hold down the after end of the hood, raise it until it doesn't try to lift off anymore, or until you can just barely see over it, whichever comes first. ... and if you can, then raise it more to generate some downforce.

Think of it this way: If you ignore the presence of the engine and the radiator, the space between the front wheels would make a decent aero tunnel, with a wing mounted upside down at the top where the hood is, and a clean air passage from the radiator intake going back and then up to the base of the windshield. Now just mentally put the engine and radiator back in place, and figure out the tinwork to maintain the airflow under the hood/wing. Probably easier with a Subaru as the substrate.


Mike Halloran
Pembroke Pines, FL, USA

RE: Racing car aerodynamic optimization

The vertical panels behind the rear wheels are clearly intended to help the rear undercar diffuser do its thing, by restricting flow from the side into that area, inducing better flow from under the car.

The strips at the windshield corners I'm not sure about. If there's a gap under them, they would tend to direct some of the pressurized air stacked up in front of the windshield around the A pillar in a relatively orderly manner, just as some station wagons are equipped with anti-spoilers(?) that direct the roof boundary layer down over the rear window.
... for different reasons, I think.
If there's no gap under them, I haven't a clue.

Mike Halloran
Pembroke Pines, FL, USA

RE: Racing car aerodynamic optimization

(OP)
I think-these cars did not have rear diffuser
panels probably restricting flow from the side into that low pressure area (diffuser effect substitute)

The strips at the windshield If you do not have the space could increase the pressure in windshield

RE: Racing car aerodynamic optimization

It depends on what the rules allow.

If you can, place the wing even higher, add some almost ground rubbing side skirts, a rear diffuser with flat underbody panels elsewhere.
Use taller wind end plates, BTW remove the wing mounts you have and make the end plates the attachment points.

Make some ducts so radiator hot air will exit from either over the hood or behind the rear wheels or both.
Drill some holes or install some louvers so air from the wheel wells will vent up to the hood.
Make it a fastback by moving the rear window further backward and filling the remaining space with either sheetmetal or a 4th window when looking it from the side.

If there are no rules for aero create a vacuum cleaner Chaparral 2J like car
http://en.wikipedia.org/wiki/Chaparral_Cars#2J
Doing so you'll get insane downforce even when standing still
A so equipped Corvette won a Road&Track skidpad challenge
http://www.readabstracts.com/Automobiles/Road-and-...
http://www.vcmc.ca/forum/showthread.php?8789-Road-...

Be bold

RE: Racing car aerodynamic optimization

(OP)
Thanks all for ideas! Thumbsup2

I would like to use big end plate at front wing(splitter)

RE: Racing car aerodynamic optimization

Sierra4000, why no diffuser? That is HUGE for aero drag as well as the entire underside of the car. You are giving away something like a full 0.1 point of CD.

RE: Racing car aerodynamic optimization

(OP)
140Airpower - I tried made diffuser (this was very high weight about 20 Kg !!)
I am thinking using side plate (attached picture) with minimal added of weight
what your opinion?

RE: Racing car aerodynamic optimization

make a difusor from a lighter material - some plastics, CF, or what yachts are made of (some resin, don't remember the name) can be manually molded into a desired shape.

RE: Racing car aerodynamic optimization

What are the speeds we are talking here?

Are there any restriction on using other car model? This one will need quite a bit of tinkering!
1. Re-profile curves over the tyres, if tyres cannot be narrower. Front tyre curve seems notorious to me -drag wise!
2. Strip out the rain-stopper strip above the windows. If you are racing, you dont need them!
3. Two front holes, if they are head lights, bring them in forward - in line with the other surfaces. Else fill them or make them thru to tyres, if you have information that ventilation is beneficial at that location.
4. Reduce/remove the hump over the hood or atleast give a cure, instead of current filleted corners.
5. Seal all gaps between surfaces, for example front guard and car body!
6. If its for racing, remove the aft door handles, cover them.
7. Bring the window glass in line with door surface. Or atleast cover the aft window with sheet metal. And remove the protruding black circle.
8. Move up the spoiler, currently its in the wake of car, not sure how effective it actually is.
9. Cover the exposed machinery on either side, below the door.
10......and lots more
What are the considerations? Time/Cost/Car Model?

Regards,
Tejas

RE: Racing car aerodynamic optimization

(OP)
Thanks for all proposals!

wing I gradually lowered to reducing drag and improve bottom(rear end) air extracted
because low position still this wing is very effective.

here starting point for rear wing location:

RE: Racing car aerodynamic optimization

(OP)
car maximum speed is 220 km / h, but averaged race 120 to 170 km / h

Radek

RE: Racing car aerodynamic optimization

That's quite a bit of speed!

There are lot of other things, which you may probably already thinking about:
1. Change wing mirrors in style with new cars. Instead of just a rectangular piece, you can put mirrors from current car variants. Else you can get rid of wing mirrors, can try body mounted camera. You can argue F1 uses rectangular mirrors!
2. If you modify the tyre covers, you will more or less end up with something similar to Beetle car. Not sure, how beautiful it would look thou!
3. The tail end, I believe you are going to cover. Basically, Photo of Car in Wind Tunnel's Brown portion of the body, unless you have some specific reason!

RE: Racing car aerodynamic optimization

(OP)
Yes SAjet,
I do not need any mirrors(always only one car on track)

sorry, points 2.and 3. I do not understand well.

RE: Racing car aerodynamic optimization

Why not use a front end more like this car:
http://casualsociety.co.za/?p=1820

And eliminate the wheel arch extensions and fit narrower tires like Greg said.
To compromise this redesign the cars bottom to include ground effect (http://casualsociety.co.za/?p=1820)

Properly designed, you can have superior traction at lower speeds as well as reduced drag at higher speeds. This will also give you better acceleration (lowered rotating inertia from thinner wheels and tires)

Cheers,

peace
Fe (IronX32)

RE: Racing car aerodynamic optimization

(OP)
Thanks for the suggestions,


I have a flat floor - I want slight downward inclination front end body


previously I had an 8 inch wheel width,
after installing these 10 inch wheels, the car improving time approximately around 1 second at 1 km in hill climb technical tracks!
so I'm really do not want to narrow wheels

RE: Racing car aerodynamic optimization

Then you need to fair the wheel arch extensions, e.g. with styrofoam or balsa wood or similar.

Mike Halloran
Pembroke Pines, FL, USA

RE: Racing car aerodynamic optimization

(OP)
OK,
can this hole(bumper side output) help air evacuation and further reduce pressure in the under hood
and improve the efficiency my front splitter?

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close