SEAT Ibiza - rwd turbo
Discussion
I don't mean to piss all over your lovely end plates with my fire hose of half-formed ideas based on about 10 mins experience, but I honestly think your wing will be little more than a parachute!
The trouble I had getting a relatively softcore modified NACA profile to work with my hatchback tells me that yours has way too much curvature to keep flow attached. I understand it's cool because #BTCC but do you reckon it's going to work? Might be worth sticking a big relatively flat single plane on there, especially if your height is limited by regs.
The trouble I had getting a relatively softcore modified NACA profile to work with my hatchback tells me that yours has way too much curvature to keep flow attached. I understand it's cool because #BTCC but do you reckon it's going to work? Might be worth sticking a big relatively flat single plane on there, especially if your height is limited by regs.
Olivera said:
Max Torque, what's the reason for going RWD rather than 4WD?
4wd is for poofters.......... ;-)More seriously, the car was built as a rally car, so if you're 4wd you're competing against pukka WRC cars and you aren't going to beat those! The 2wd classes were much freer and there were some nice advantages in being 2wd (including much lower weight limits etc) the main one being that i didn't have to spend £60k on a fully active "3 diff" transmissions system from Xtrac!
CamMoreRon said:
I don't mean to piss all over your lovely end plates with my fire hose of half-formed ideas based on about 10 mins experience, but I honestly think your wing will be little more than a parachute!
The trouble I had getting a relatively softcore modified NACA profile to work with my hatchback tells me that yours has way too much curvature to keep flow attached. I understand it's cool because #BTCC but do you reckon it's going to work? Might be worth sticking a big relatively flat single plane on there, especially if your height is limited by regs.
Remember this is a "Low speed wing" not an F1 car wing or aeroplane wing! It needs to work between around 50mph and 120 mph max. That means a deep chord with high curvature. Your typical wing you see people put on race cars often look like it's come off a Boeing and works well at around 200mph with a commensurately good L/D ratio, but the only downforce it provides in the real world is the weight of the wing itself....... It's also worth noting that the wing i have from the Mondeo BTCC is a combined wing anf gurney flap. It's difficult to tell from the pics, but it has a relatively shallow camber on the underside, and the large rear vertical section is designed to effectively "stall" the top side.The trouble I had getting a relatively softcore modified NACA profile to work with my hatchback tells me that yours has way too much curvature to keep flow attached. I understand it's cool because #BTCC but do you reckon it's going to work? Might be worth sticking a big relatively flat single plane on there, especially if your height is limited by regs.
Of course, it was designed with CFD and optimised in a wind tunnel for the BTCC car, which as it was a mondeo, and had the wing on the boot, mean't it's AOA is optimised for slightly downward flowing air coming down off the rear screen rake and you'll notice the centre section has less camber compared to the ends (which are further away from the cabin and hence seeing more horizontal airflow. In my case, it's high enough to get air pretty much from a straight forwards direction, so it won't be drag optimised. However, the BTCC mondeo had around 310bhp, and would run to over 150mph. My car has 627bhp and runs out of gears at 121mph so i don't think a bit of drag is going to be an issue........ ;-)
Edited by anonymous-user on Friday 10th October 22:06
Max_Torque said:
Remember this is a "Low speed wing" not an F1 car wing or aeroplane wing! It needs to work between around 50mph and 120 mph max. That means a deep chord with high curvature. Your typical wing you see people put on race cars often look like it's come off a Boeing and works well at around 200mph with a commensurately good L/D ratio, but the only downforce it provides in the real world is the weight of the wing itself....... It's also worth noting that the wing i have from the Mondeo BTCC is a combined wing anf gurney flap. It's difficult to tell from the pics, but it has a relatively shallow camber on the underside, and the large rear vertical section is designed to effectively "stall" the top side.
Of course, it was designed with CFD and optimised in a wind tunnel for the BTCC car, which as it was a mondeo, and had the wing on the boot, mean't it's AOA is optimised for slightly downward flowing air coming down off the rear screen rake and you'll notice the centre section has less camber compared to the ends (which are further away from the cabin and hence seeing more horizontal airflow. In my case, it's high enough to get air pretty much from a straight forwards direction, so it won't be drag optimised. However, the BTCC mondeo had around 310bhp, and would run to over 150mph. My car has 627bhp and runs out of gears at 121mph so i don't think a bit of drag is going to be an issue........ ;-)
Great reply, thanks. Of course, it was designed with CFD and optimised in a wind tunnel for the BTCC car, which as it was a mondeo, and had the wing on the boot, mean't it's AOA is optimised for slightly downward flowing air coming down off the rear screen rake and you'll notice the centre section has less camber compared to the ends (which are further away from the cabin and hence seeing more horizontal airflow. In my case, it's high enough to get air pretty much from a straight forwards direction, so it won't be drag optimised. However, the BTCC mondeo had around 310bhp, and would run to over 150mph. My car has 627bhp and runs out of gears at 121mph so i don't think a bit of drag is going to be an issue........ ;-)
Yeah I see what you mean now you've explained.. I think it was this photo that got me worried, as it just looks like a brick wall the whole way across!
But I found a good pic on t'internet (below) that shows the profile isn't that extreme, especially at the centre, and the sort-of gurney flap towards the sides.
Do your reg's say anything about wing height, or can you basically stick it up as high as you like?
PhillipM said:
That's still waaaay more camber than my rear wing, which makes me wonder how much more I could get away with...
Stick some wool tufts to the underside, strategically place a GoPro to look at those tufts and take it for a drive. Increase AOA until tufts droop away from underside showing the boundary layer has become disconnected!(Even better, perforate the underside and use a fan to actively remove the boundary layer....... ;-)
CamMoreRon said:
Max_Torque said:
Remember this is a "Low speed wing" not an F1 car wing or aeroplane wing! It needs to work between around 50mph and 120 mph max. That means a deep chord with high curvature. Your typical wing you see people put on race cars often look like it's come off a Boeing and works well at around 200mph with a commensurately good L/D ratio, but the only downforce it provides in the real world is the weight of the wing itself....... It's also worth noting that the wing i have from the Mondeo BTCC is a combined wing anf gurney flap. It's difficult to tell from the pics, but it has a relatively shallow camber on the underside, and the large rear vertical section is designed to effectively "stall" the top side.
Of course, it was designed with CFD and optimised in a wind tunnel for the BTCC car, which as it was a mondeo, and had the wing on the boot, mean't it's AOA is optimised for slightly downward flowing air coming down off the rear screen rake and you'll notice the centre section has less camber compared to the ends (which are further away from the cabin and hence seeing more horizontal airflow. In my case, it's high enough to get air pretty much from a straight forwards direction, so it won't be drag optimised. However, the BTCC mondeo had around 310bhp, and would run to over 150mph. My car has 627bhp and runs out of gears at 121mph so i don't think a bit of drag is going to be an issue........ ;-)
Great reply, thanks. Of course, it was designed with CFD and optimised in a wind tunnel for the BTCC car, which as it was a mondeo, and had the wing on the boot, mean't it's AOA is optimised for slightly downward flowing air coming down off the rear screen rake and you'll notice the centre section has less camber compared to the ends (which are further away from the cabin and hence seeing more horizontal airflow. In my case, it's high enough to get air pretty much from a straight forwards direction, so it won't be drag optimised. However, the BTCC mondeo had around 310bhp, and would run to over 150mph. My car has 627bhp and runs out of gears at 121mph so i don't think a bit of drag is going to be an issue........ ;-)
Yeah I see what you mean now you've explained.. I think it was this photo that got me worried, as it just looks like a brick wall the whole way across!
But I found a good pic on t'internet (below) that shows the profile isn't that extreme, especially at the centre, and the sort-of gurney flap towards the sides.Do your reg's say anything about wing height, or can you basically stick it up as high as you like?
Some quite good info here, but it's for aeroplanes, so you need to turn your screen upside down to view it in terms of "downforce"!
Highlift wings
(and worth remembering, that even at whilst flying "slowly" at landing, a typical airliners doing around 160mph!
There is also some interesting lift & drag data here:
Reverie CF wing sections
for a relatively deep section wing, showing L/Ds between around 13 and 8 for AOAs between 4 and 18 deg respectively.
Reverie CF wing sections
for a relatively deep section wing, showing L/Ds between around 13 and 8 for AOAs between 4 and 18 deg respectively.
Max_Torque said:
Stick some wool tufts to the underside, strategically place a GoPro to look at those tufts and take it for a drive. Increase AOA until tufts droop away from underside showing the boundary layer has become disconnected!
(Even better, perforate the underside and use a fan to actively remove the boundary layer....... ;-)
There's gonna be some wool tuft runs for setup - mainly because I need to be careful with the wing stalling due to the amount of pitch it needs to contend with, jelly spec suspension and all - but even so, the overall camber is only something like 40* at the minute, any more than that and the simulations (I know, they're only rough, but still) show a lot of seperation on the trailing edge otherwise.(Even better, perforate the underside and use a fan to actively remove the boundary layer....... ;-)
Given that the end of the car transitions into two huge vortices, I suspect a flat/horizontal wing is faaar from optimum. I'd bet it's also waaay different from the Mondeo to the point that the Mondeo wing is pointless.
I'd put some bits of string on the end of protruding poles stuck to the window approximately the distance the wing might be and then go video tape the results at various speeds to get a rough idea of what the air is actually doing and how you're going to get some downforce out of it without massive drag.
Of course, if it's just for the Halfords competition, then it's looking great!
I'd put some bits of string on the end of protruding poles stuck to the window approximately the distance the wing might be and then go video tape the results at various speeds to get a rough idea of what the air is actually doing and how you're going to get some downforce out of it without massive drag.
Of course, if it's just for the Halfords competition, then it's looking great!
AER said:
Given that the end of the car transitions into two huge vortices, I suspect a flat/horizontal wing is faaar from optimum. I'd bet it's also waaay different from the Mondeo to the point that the Mondeo wing is pointless.
I'd put some bits of string on the end of protruding poles stuck to the window approximately the distance the wing might be and then go video tape the results at various speeds to get a rough idea of what the air is actually doing and how you're going to get some downforce out of it without massive drag.
Of course, if it's just for the Halfords competition, then it's looking great!
You are not wrong my erstwhile antipodean ex-colleague! I've made the end plates large enough to hold pretty much any sensible wing section, and those sections will be adjustable for AOA, so as you mention, i can do a little bit of optimisation. The ex BTCC wing is ok for now, i'm damm sure it's not optimum, but i've got no race/championship to win, so to be frank, it's probably 75% "pub ammo" as you point out...... ;-)I'd put some bits of string on the end of protruding poles stuck to the window approximately the distance the wing might be and then go video tape the results at various speeds to get a rough idea of what the air is actually doing and how you're going to get some downforce out of it without massive drag.
Of course, if it's just for the Halfords competition, then it's looking great!
There are not words in English to describe the epic nature of this build, the attention to detail on the mechanical side of it is breathtaking, and could put even the most expensive super cars look thrown together. But bloody hell you are good with the electrical side of things, I think most of us on here would have set fire to the car, cubed it set fire to it again and been locked into a small padded room attempting even the early stages,
Can't wait to see video of this being used in anger.
Can't wait to see video of this being used in anger.
jebus said:
There are not words in English to describe the epic nature of this build, the attention to detail on the mechanical side of it is breathtaking, and could put even the most expensive super cars look thrown together. But bloody hell you are good with the electrical side of things, I think most of us on here would have set fire to the car, cubed it set fire to it again and been locked into a small padded room attempting even the early stages,
Can't wait to see video of this being used in anger.
^^Thanks, i try my best! ;-)Can't wait to see video of this being used in anger.
After what feels to be like days of sanding, filling, priming, more sanding, polishing etc i have nearly finished the patterns for the wing end plates:
End plate on the right just waiting for it's final polish, plate on the left still in un-sanded high gloss.
Also patterns for my carbon "smart" steering wheel and a new dash insert piece that will house the master WARN/caution controller:
More sanding/finishing tomorrow..............
End plate on the right just waiting for it's final polish, plate on the left still in un-sanded high gloss.
Also patterns for my carbon "smart" steering wheel and a new dash insert piece that will house the master WARN/caution controller:
More sanding/finishing tomorrow..............
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