Mounting front dive planes
Discussion
rossins said:
Morning,
After some guidance - what is the best way to mount the front dive planes & at what angle.
Thanks in advance.
Simon
Your question is open ended, why are you fitting dive planes? have you altered/improved the rear aero? one without the other can cause significant brake balance issues.After some guidance - what is the best way to mount the front dive planes & at what angle.
Thanks in advance.
Simon
Are you running a front splitter? if so what length is the lip?
A photo of the car in its current state may help.
Despite the look and the initial impression you get, dive planes don't directly give you downforce from wind hitting them (not much any way). The general consensus is that if you have dive planes they will swirl the air going down the side of the car and help prevent it going underneath, so any suction created under the car is maintained (this is possibly why they are also refered to as Canards which is taken from the special wing tips on aircraft to create a swirling effect although i'm not sure why). This effect is also helped considerably with the use of side skirts as they also keep the swirling air from getting drawn under the middle of the car.
However, If you have a splitter it directly increases pressure at the front end irrespective of dive planes so F.C. your statement only really refers to fitting a splitter and not dive planes...as far as i can figure out anyway.
Myself and another Ultima owner are only just sticking or toes in the aerodynamic waters so i am pretty certain that what i say above is sound, but if anyone has more knowledge on the subject (which wouldn't be hard) then i look forward to hearing more.
Rossins: i know that doesn't really answer your question, but if you are fitting generic dive planes to suit any car, then you would have to take it to a wind tunnel with down force testing to then find the optimum position as it's a trade off between drag and gains in down force which is why you will see some cars with them fitted at a steep angle and some at a shallow angle...so in other words no one can give you the correct answer unless they have fitted those exact dive planes and tested them.
However, If you have a splitter it directly increases pressure at the front end irrespective of dive planes so F.C. your statement only really refers to fitting a splitter and not dive planes...as far as i can figure out anyway.
Myself and another Ultima owner are only just sticking or toes in the aerodynamic waters so i am pretty certain that what i say above is sound, but if anyone has more knowledge on the subject (which wouldn't be hard) then i look forward to hearing more.
Rossins: i know that doesn't really answer your question, but if you are fitting generic dive planes to suit any car, then you would have to take it to a wind tunnel with down force testing to then find the optimum position as it's a trade off between drag and gains in down force which is why you will see some cars with them fitted at a steep angle and some at a shallow angle...so in other words no one can give you the correct answer unless they have fitted those exact dive planes and tested them.
^^ What he said above ^^ I've been doing a lot of reading and find the subject quite interesting.
It seems while there is direct increase on the front using dive planes the larger gain is about helping to seal the under body using vortices for overall downforce (leveraging the ground effect of the splitter/underbody/skirts and diffusers). This was developed after formula cars had skirts that basically had so much ground effect that if they lost it for what aever reason there was no chance in hell they could recover the car using mechanical grip (and subsequently skeeted off in to the nearest gravel pit/wall). So skirts were banned (and not practical for road applications, but lets face it dive planes are mainly for look for a road car). Since F1 introduced the stepped floor to again reduce ground effect, some very very clever people alter the front wings to work with the front tyres to produce the right vortices.
Anyway.....
Throwing all science aside and facing that fact not many of us have CFD and none of us (hands up if you do) have access to a wind tunnel; Indulge me while I make some general observations:
The upper dive plane generally points to the top of the front wheel arch with the angle increasing from 15 up to 60 degrees. The lower dive plane supports the upper with the front facing of the dive plane equi-distant between the splitter and the upper dive plane.
In terms of increasing front down force the steps are.....
- Front splitter ( with as much of the under front clam covered and flush with the floor)
- Front splitter should be as far forward as practicality allows. Factory I think suggest 70mm for practical balance. 100mm plus for more.
- dive planes (or potentially splitter end fences)
Aero must remain balanced front and rear so generally a rear wing should be match with a splitter, Increased rear wing, larger or move back you should lengthen the splitter & dive planes..... roughly.
Here are some examples from radicals which are track focused and put through plenty of testing:
Factory SR3 set up:
And Sr10 racing LMP with some impressive Aero:
Vid: https://www.youtube.com/watch?v=7BuP12uYZg8
and more reading linked to from another tread (I think)
http://trackdriver.com/blog/wp-content/uploads/201...
May revise once Ive done some more digging
It seems while there is direct increase on the front using dive planes the larger gain is about helping to seal the under body using vortices for overall downforce (leveraging the ground effect of the splitter/underbody/skirts and diffusers). This was developed after formula cars had skirts that basically had so much ground effect that if they lost it for what aever reason there was no chance in hell they could recover the car using mechanical grip (and subsequently skeeted off in to the nearest gravel pit/wall). So skirts were banned (and not practical for road applications, but lets face it dive planes are mainly for look for a road car). Since F1 introduced the stepped floor to again reduce ground effect, some very very clever people alter the front wings to work with the front tyres to produce the right vortices.
Anyway.....
Throwing all science aside and facing that fact not many of us have CFD and none of us (hands up if you do) have access to a wind tunnel; Indulge me while I make some general observations:
The upper dive plane generally points to the top of the front wheel arch with the angle increasing from 15 up to 60 degrees. The lower dive plane supports the upper with the front facing of the dive plane equi-distant between the splitter and the upper dive plane.
In terms of increasing front down force the steps are.....
- Front splitter ( with as much of the under front clam covered and flush with the floor)
- Front splitter should be as far forward as practicality allows. Factory I think suggest 70mm for practical balance. 100mm plus for more.
- dive planes (or potentially splitter end fences)
Aero must remain balanced front and rear so generally a rear wing should be match with a splitter, Increased rear wing, larger or move back you should lengthen the splitter & dive planes..... roughly.
Here are some examples from radicals which are track focused and put through plenty of testing:
Factory SR3 set up:
And Sr10 racing LMP with some impressive Aero:
Vid: https://www.youtube.com/watch?v=7BuP12uYZg8
and more reading linked to from another tread (I think)
http://trackdriver.com/blog/wp-content/uploads/201...
May revise once Ive done some more digging
Edited by confusionhunter on Thursday 21st January 20:19
chucknorris said:
F.C. said:
They reduce drag and therefore fuel used.
Thanks, i've always wondered, that's interesting...add something that will no doubt add some drag but reduce overall drag by more than it adds...wow!F.C. said:
chucknorris said:
F.C. said:
They reduce drag and therefore fuel used.
Thanks, i've always wondered, that's interesting...add something that will no doubt add some drag but reduce overall drag by more than it adds...wow!I wonder what ground skidding side skirts would do for an Ultima's handling/aero????
Paul
Storer said:
They reduce the air spilling over the end of the wing and use it to create lift. More lift from the existing wing length equals less wing to push through the air equals less fuel.
I wonder what ground skidding side skirts would do for an Ultima's handling/aero????
Paul
The cleaner the air under the car the faster it exits the rear the slower air over the car creates high pressure to the lower pressure underneath. I wonder what ground skidding side skirts would do for an Ultima's handling/aero????
Paul
Sky's the limit here you could go so far as to make the car un-drivable or at least need stiffer spring rates.
There was an interesting article in Evo a while back where they tested a variety of aero aids on an Exige cup car.
If I recall correctly, addition of dive planes have a very small amount of additional front downforce, it gave fractionally faster lap times, fractionally slower terminal speed but apparently the biggest difference when fitted with a front splitter was in the confidence they had in the car. - perhaps as a result of the airflow being tidier as already mentioned.
They look cool too
If I recall correctly, addition of dive planes have a very small amount of additional front downforce, it gave fractionally faster lap times, fractionally slower terminal speed but apparently the biggest difference when fitted with a front splitter was in the confidence they had in the car. - perhaps as a result of the airflow being tidier as already mentioned.
They look cool too
deadscoob said:
It could be, not on road settings though.
What did they Noble guys find? Did they do some proper, controlled, before and after comparisons?
Some of the guys did some at MIRA early days.What did they Noble guys find? Did they do some proper, controlled, before and after comparisons?
I think you'll find its been all string and tracer paint from there on.
https://www.youtube.com/watch?v=hT0NgBbJPck
Note the wheel arch grills, notice how they protrude above the line of the bodywork, this is to introduce the trapped air into the boundary layer and so smooth flow over the rest of the car, if the grills don't protrude like these they will relieve pressure from the wheel wells but add turbulent air over the rest of the car, which is of course not desirable.
Edited by F.C. on Friday 22 January 16:16
Here is more of some interest:
https://www.youtube.com/watch?v=E9ZSAX56m0E
And how is this for clever??
https://www.youtube.com/watch?v=E9ZSAX56m0E
Edited by F.C. on Friday 22 January 16:44
Needless to say aerodynamics is highly complex subject as nothing can be viewed in isolation, however, in general...
1. Dive planes/canards utilise the principal of vortex lift (very similar to the strakes at the front of planes and missiles), which generates a strong vortex downstream of the device
2. The vortex can be very useful if positioned correctly - as mentioned F1 front wings and some prototype cars have similar devices mounted low to create a vortex which runs close to the floor to 'seal' the underside of the car to maintain the low pressure
3. The vortex can also be pain (especially in rear engined cars) as it can heavily influence cooling capability (think where the rear air intakes are on the Ultima). We have measured this directly with our gearbox running temp, which has the cooler in the RHS side pod
4. Positioned correctly, they can be used to vent pressure out of the front wheel arches (in addition with louvres as per FC's post above)
Back to the original OP's question, bolt them on with a couple of M6 bolts and large washers on the inside of the clam.
Jonny
1. Dive planes/canards utilise the principal of vortex lift (very similar to the strakes at the front of planes and missiles), which generates a strong vortex downstream of the device
2. The vortex can be very useful if positioned correctly - as mentioned F1 front wings and some prototype cars have similar devices mounted low to create a vortex which runs close to the floor to 'seal' the underside of the car to maintain the low pressure
3. The vortex can also be pain (especially in rear engined cars) as it can heavily influence cooling capability (think where the rear air intakes are on the Ultima). We have measured this directly with our gearbox running temp, which has the cooler in the RHS side pod
4. Positioned correctly, they can be used to vent pressure out of the front wheel arches (in addition with louvres as per FC's post above)
Back to the original OP's question, bolt them on with a couple of M6 bolts and large washers on the inside of the clam.
Jonny
Found an interesting piece on that - cutouts were made mandatory after some flipping incidents. Went on to say that when it was introduced it made the cars less stable as it effectively moved the centre of gravity forwards. Subsequently they've designed aero around those cutouts.
Going back to the post, I have a pair mounted in around the same position as the radicals lower ones. My thoughts were they run those on the sr8s and rxcs which aren't a million miles away dimensionally or weight to an Ultima, plus it gives the option for an upper pair.
Am very happy with the way the car feels and front end grip, but think the dive planes only contribute a small amount.
Going back to the post, I have a pair mounted in around the same position as the radicals lower ones. My thoughts were they run those on the sr8s and rxcs which aren't a million miles away dimensionally or weight to an Ultima, plus it gives the option for an upper pair.
Am very happy with the way the car feels and front end grip, but think the dive planes only contribute a small amount.
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