F1technical.net

Every method of producing downforce has already been tried over the years in various types of auto racing. A review of past race car aero designs would be helpful. Why limit your design options if it is not necessary?

What seems to be the most efficient approach is a huge pair of underbody tunnels combined with active suspension. The underbody performance can be improved by taking advantage of the radiator and engine exhaust flows. Active control of front/rear wings would also be very effective.

theslayermon wrote:Simple definitely seems the way to start, what i would do is plan out all the space needed for and make a smooth base over it (not for any down force, just something that shouldn't make a large amount of drag) and then move through and in turn add in the major areas of down force production. After you have a simple and working base then try the more interesting/odd ideas and refine things. Having a solid base would be a good priority.

BTW what CFD program are you using? I really like your second picture.

I am using Flow Simulation from DS that's built into Solidworks.

Greg Locock wrote:I've just extended the spreadsheet, it now shows the fall off of cornering performance with speed, as the power required to slide the tires sideways exceeds engine power.

I'm pretty pleased with that. In this case it is for a generic F1 car

http://www.mediafire.com/view/o9t8uovbe ... _aero2.png

I have flat out copied you in making a spreadsheet like the one you have pictured. I will look into the tire slip thing tomorrow; time to get some sleep!




I am also starting to read up on race car aerodynamics topics. I am beginning to see the benefits of the flow if it is kept attached. Some front wing analysis pictures:
























Also, some random snapshots I took of the center rear diffuser:

Greg Locock wrote:FFS read Katz, best 30 bucks ever.

I didn't have this in my library but had heard it mentioned a few times.. so I figured I'd pick it up. Through the magic of Amazon, ordered it the other night and it showed up by 1030 the next morning (how they do that on 2 day shipping is beyond me).

Anyway, gave it a read through the past couple days. Pretty good! Have to echo Greg's sentiment here, it's a worthwhile pick up and not at all bad or difficult read.

Jersey Tom wrote:How do F1 cars generate "so much" downforce.. they turn the flow quite well? (Which to do so you will want to keep the flow attached, which will require airfoils rather than plates).

Then again, my expertise is tires, so...

JT,

Not to get nit picky but I see "turning the flow" as a common misconception about aero, I supposed you could refer to that as "vertical displacement". The two are not very well connected. Thats really where aero gets away from being what could be called "intuitive".

Maybe this helps as you´re car looks like an old Group C.

http://www.mulsannescorner.com/allardj2x.html

gixxer_drew wrote:JT,

Not to get nit picky but I see "turning the flow" as a common misconception about aero, I supposed you could refer to that as "vertical displacement". The two are not very well connected. Thats really where aero gets away from being what could be called "intuitive".

Oh? Conservation of momentum isn't real then?

isn't "turning the flow" just referring to the circulation generated?

matt21 wrote:Maybe this helps as you´re car looks like an old Group C.

http://www.mulsannescorner.com/allardj2x.html

Or even a successful one such as: http://www.mulsannescorner.com/JaguarXJR-14.html

They did tests and reckoned they could get 10,000lb of downforce at 200mph. Huge drag though.

In more usual trim they got

5880 lbs. of downforce for 1400 lbs. drag (figures quoted at 200 mph)

Edit: here are some figures for the XJR-14 http://www.mulsannescorner.com/aerodata ... jr-14.html
Look here for loads more: http://www.mulsannescorner.com/data.html

Jersey Tom wrote:

gixxer_drew wrote:JT,

Not to get nit picky but I see "turning the flow" as a common misconception about aero, I supposed you could refer to that as "vertical displacement". The two are not very well connected. Thats really where aero gets away from being what could be called "intuitive".

Oh? Conservation of momentum isn't real then?

Hello there straw man.

gixxer_drew wrote:

Jersey Tom wrote:

gixxer_drew wrote:JT,

Not to get nit picky but I see "turning the flow" as a common misconception about aero, I supposed you could refer to that as "vertical displacement". The two are not very well connected. Thats really where aero gets away from being what could be called "intuitive".

Oh? Conservation of momentum isn't real then?

Hello there straw man.

Then what specifically are you saying about flow turning being a misconception or somehow counter-intuitive? As I understand it, momentum of a closed system (say a control volume around a car) is conserved unless acted upon by an outside force. Or conversely, to be generating more force the momentum of the flow must change more. The two are related.

To me, that makes things more intuitive - that to create a healthy amount of downforce you ultimately will need to have the flow stay attached and be redirected, which is done best by an airfoil rather than a big plate exposed to the air trying to capture pressure on the one side.

Jersey Tom wrote:

gixxer_drew wrote:

Jersey Tom wrote:
Oh? Conservation of momentum isn't real then?

Hello there straw man.

Then what specifically are you saying about flow turning being a misconception or somehow counter-intuitive? As I understand it, momentum of a closed system (say a control volume around a car) is conserved unless acted upon by an outside force. Or conversely, to be generating more force the momentum of the flow must change more. The two are related.

To me, that makes things more intuitive - that to create a healthy amount of downforce you ultimately will need to have the flow stay attached and be redirected, which is done best by an airfoil rather than a big plate exposed to the air trying to capture pressure on the one side.

The forces are generated by the pressures acting on the surfaces, the laws mean you have to turn flow to make downforce. It doesn't mean that the amount you turn the flow determines the amount of downforce. There are designs that do better or worse with any amount of flow "turning". Agree 100% about an airfoil doing much better than a plate though!

gixxer_drew wrote:It doesn't mean that the amount you turn the flow determines the amount of downforce.

I would think that it would have to be the same, and that force to likewise be equivalent to the pressure difference across all surfaces. To what else could you attribute the change in flow momentum if not a difference in force acting on it?

Jersey Tom wrote:

gixxer_drew wrote:It doesn't mean that the amount you turn the flow determines the amount of downforce.

I would think that it would have to be the same, and that force to likewise be equivalent to the pressure difference across all surfaces. To what else could you attribute the change in flow momentum if not a difference in force acting on it?

Not all the surfaces effected by forces in motion belong to the car or are making downforce even when they are.

Just an update, I figured out that the rolling road was interfering with the values so inserting surface parameters I get around 4900N of downforce with 1450N of drag at 50m/s. I also feel like there is quite a bit of refining to be done here. An admin can move this to the Engineering Projects forum as this is becoming more of a project thread.

I am analysing a 2014 and a 2013 F1 front wing as part of my final project

I am trying to 3d model the front wing so I can then prototype it and test it in a wind tunnel and then make a comparison

Can somebody please tell me how to go about this?! I am trying to do it in solidworks but I need help
Any help would be greatly appreciated!
Thanks!