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Re: Concave Vs Convex?
Posted: 09 Jan 2012, 07:40
by MIKEY_!
The separation I'm talking about is in the area around the wheels. They aren't all that streamlined there so there may be something to gain. Anyway point is that there may be no need to try and fix that separation. As for lift: if the body of the car is creating a bit of lift anyway there's no need to add a DF creating bit to balance it.
Lightspeed: can you lower the front of the wheel 'arch' so there is a smaller horizontal gap between it and the curve of the tire? OK not much we can do about those wings then, just try to ensure they are not interacting with other body parts too much, in one of the pictures you posted the upward slope of the nose will interact wing the wing too much I think.
Re: Concave Vs Convex?
Posted: 09 Jan 2012, 18:10
by flynfrog
MIKEY_! wrote:The separation I'm talking about is in the area around the wheels. They aren't all that streamlined there so there may be something to gain. Anyway point is that there may be no need to try and fix that separation. As for lift: if the body of the car is creating a bit of lift anyway there's no need to add a DF creating bit to balance it.
Lightspeed: can you lower the front of the wheel 'arch' so there is a smaller horizontal gap between it and the curve of the tire? OK not much we can do about those wings then, just try to ensure they are not interacting with other body parts too much, in one of the pictures you posted the upward slope of the nose will interact wing the wing too much I think.
With the risk of throwing this way off topic there is very much a need to fix that separation. I would guess its a major part of the drag on the car. The better you can fair in the wheels the less drag you will have. If the body is creating lift then work should be done to make it more neutral lift is drag. I'm not talking about adding wings to give it df there is something wrong with the overall shape
Re: Concave Vs Convex?
Posted: 09 Jan 2012, 18:22
by flynfrog
Lightspeed. I would think more like this on the front of your car
you can imagine the CO2 chamber connecting at the rear of the cockpit. You can quite go over the wheels like that but you can get pretty close. Both of your ideas you have seem pretty good. You should try to combine them, think in 3D
Re: Concave Vs Convex?
Posted: 10 Jan 2012, 07:43
by MIKEY_!
The wheels aren't allowed to be covered at all. No point having that much bodywork between the wheels (up the middle of the car) other than what is absolutely necessary.
Re: Concave Vs Convex?
Posted: 10 Jan 2012, 15:53
by flynfrog
MIKEY_! wrote:The wheels aren't allowed to be covered at all. No point having that much bodywork between the wheels (up the middle of the car) other than what is absolutely necessary.
The wheels are allowed to be covered just not on the top and bottom. You most certainly want to cover as much as possible.
Re: Concave Vs Convex?
Posted: 11 Jan 2012, 01:48
by MIKEY_!
These are the best front wheel covers I think I've seen on these cars. However I think they should send air to the sides as well. These half height fairings reduce separation most.
Re: Concave Vs Convex?
Posted: 11 Jan 2012, 02:53
by flynfrog
MIKEY_! wrote:
These are the best front wheel covers I think I've seen on these cars. However I think they should send air to the sides as well. These half height fairings reduce separation most.
I am being serious here stop! You honestly have no idea what you are talking about. What are you basing all of this on? The covers on the sides of the wheel are pretty good but the front is terrible. You are trying to direct an air stream directly into an opposing flow off of the wheels.
Re: Concave Vs Convex?
Posted: 11 Jan 2012, 03:18
by MIKEY_!
Sorry, I should have said "with regard to reducing flow separation" for that last post.
Also this bit is vital:
However I think they should send air to the sides as well.
Re: Concave Vs Convex?
Posted: 11 Jan 2012, 03:21
by flynfrog
MIKEY_! wrote:Sorry, I should have said "with regard to reducing flow separation" for that last post.
Also this bit is vital:
However I think they should send air to the sides as well.
they should also be 100% taller finished better with a better shape but other than that they are great

Re: Concave Vs Convex?
Posted: 12 Jan 2012, 01:17
by MIKEY_!
nevermind...

Re: Concave Vs Convex?
Posted: 15 Jan 2012, 14:25
by Lightspeedrt
Thanks again for the input guys, flyn on my new car i have tried to adapt that front splitter style with a more free flowing shape,is there any more pictures out there so i can see more of the front? In regards to the interaction of the wing the only thing i can think of doing would be to lift it up a bit more, but by doing that it puts more stress on the supports and the wing would most likely break off.
Re: Concave Vs Convex?
Posted: 15 Jan 2012, 18:19
by flynfrog
Re: Concave Vs Convex?
Posted: 15 Jan 2012, 23:48
by Lightspeedrt
That's pretty f****ing cool to say so myself. I will be basing my next car on this then running it through cfd.
Re: Concave Vs Convex?
Posted: 16 Jan 2012, 04:15
by flynfrog
Just keep in mind that car was built long before cfd existed. The best thing I got in my mind when doing low drag stuff is not to direct air but to move it the least amount possible to get your object through it.
a good rule to remember is the rule of thirds. Your thickest section should be 1/3 back from the leading edge and the thickness should be no more than 1/3 of the total span. It gets hard to implement in real life. It is not the final word on airfoils but its a good starting point.
Re: Concave Vs Convex?
Posted: 17 Jan 2012, 08:27
by Lightspeedrt
I believe i read that statement in a topic about NACA air foils, it is featured in our folio.