Russman's Time Attack Build

[Russman]

Need bigger wing.

If you can find me someone that makes a bigger wing I'll put it on my car haha.

The guy that made it can't go any bigger because his tooling was maxed at 1.8m. Campbell asked him to make him a 2m wing and he said no lol

[SimonR32]

Russman, what's your suspension set up like? Camber, caster and toe etc. Would love some insight as at the moment I just guess what I need

[Russman]

from memory...

Front.

9deg Castor, 4deg camber. 2mm toe out

Rear.

2deg camber. 0 toe.

Was originally 0 toe front but found it was understeering on corner entry, even low speed so we took it to 2mm toe out and it's was better. Not always the case though.

Camber could be a little more in the front but my spring rates are pretty high so doesn't really 'lean' as much as other setups.

All this seemed to work well at superlap. The tyre wear was very even so must have been ok.

[Beer Baron]

great incar mate, good driving. nice gear selection and some good lines. car looks very nice through T1 for a car with fairly minimal aero and set-up time at the track.

very impressed.

[Russman]

great incar mate, good driving. nice gear selection and some good lines. car looks very nice through T1 for a car with fairly minimal aero and set-up time at the track.

very impressed.

Thanks Richard. I am hoping to overlay the car speed data on a video if I figure out how to do it. I think T1 speed was 181kph. How does that compare to other cars? Do you know?

[SimonR32]

from memory...

Front.

9deg Castor, 4deg camber. 2mm toe out

Rear.

2deg camber. 0 toe.

Was originally 0 toe front but found it was understeering on corner entry, even low speed so we took it to 2mm toe out and it's was better. Not always the case though.

Camber could be a little more in the front but my spring rates are pretty high so doesn't really 'lean' as much as other setups.

All this seemed to work well at superlap. The tyre wear was very even so must have been ok.

I think mine was ;

Front:

9deg castor, 2.5deg camber and 0mm toe

Rear:

0.75deg and 0 toe

So fairly close, will do some changes and let you know how I go. The extra camber in the front may explain me ripping apart the ouside of the fronts last time I was out haha

Thanks

Edited August 22, 2011 by SimonR32

[Russman]

I think mine was ;

Front:

9deg castor, 2.5deg camber and 0mm toe

Rear:

0.75deg and 0 toe

So fairly close, will do some changes and let you know how I go. The extra camber in the front may explain me ripping apart the ouside of the fronts last time I was out haha

Thanks

What sort of tracks? spring rates? Camber is your friend for places like EC. Long loaded corners. Last year I had about 2.5-3deg on the fronts and the blocks on the tyres were moving across to one side!

[N1GTR]

Just thinking about volume, how do you have so much drive by noise? Other cars there with straight pipe exhausts and external gates didnt sound anywhere as good for the most part

[Russman]

I was told it wasn't loud enough haha. It's just a straight through 3.5 with twin 3.5 tips. Matt made it.

[SimonR32]

What sort of tracks? spring rates? Camber is your friend for places like EC. Long loaded corners. Last year I had about 2.5-3deg on the fronts and the blocks on the tyres were moving across to one side!

Barbs is about the only track we get over here in Perth haha

Spring rates are 8/6

[Roy]

It helps that you are running Tein REs which are a great shock and also the custom sway bars. I think your bars are better then the ARC ones I replaced them with

In all seriousness, do you understand where the extra lap time came from last year to this year? Was it 0.6-0.8 second just driving the track more...1.0-1.5 in aero...1.5-2.0 in tyres/suspension and 1.0 second or so in grunt????

Curious to hear your thoughts...and great vid

[Duncan]

a genuine 180 is right on the money, especially on semis...well done. Great times overall

[Count Grantleyish]

If you can find me someone that makes a bigger wing I'll put it on my car haha.

The guy that made it can't go any bigger because his tooling was maxed at 1.8m. Campbell asked him to make him a 2m wing and he said no lol

May ask the dude who made bloke with full blown time attack R35 (Handbrake - I think it's his username), this wing looked pretty big from photos.

[Russman]

It helps that you are running Tein REs which are a great shock and also the custom sway bars. I think your bars are better then the ARC ones I replaced them with

In all seriousness, do you understand where the extra lap time came from last year to this year? Was it 0.6-0.8 second just driving the track more...1.0-1.5 in aero...1.5-2.0 in tyres/suspension and 1.0 second or so in grunt????

Curious to hear your thoughts...and great vid

I'm still not convinced that a 27mm at the front is the right thing but yeah swaybars overall are working well.

I would say the biggest improvement is the power and torque. It's so much more linear and the power is just always propelling the car forward regardless of revs, prob 3 secs. Also the extra rubber is helping, not sure to what extent. 1-2 sec? Aero probably 1 sec purely for turn 1 and maybe a bit on turn 4 and 10.

May ask the dude who made bloke with full blown time attack R35 (Handbrake - I think it's his username), this wing looked pretty big from photos.

Haha I was only joking. This one is big enough...

[Beer Baron]

yeah 180 (assuming that's loweest speed through T1) is pretty good. plenty of people tell me all the time they pull 220 etc through there on streeties but they most likely have one hand firmly around their cock whilst saying it. from looking at data logs from lots of serious cars it takes a lot to get to even 200km/h. marks advan/RGM R34 is around the 200 mark now but that came with lots of aero work and 295 wide semis! cyber's T1 speed is insane, something close to 220 (yes I've seen their data too). and yet their front straight top speed is quite low (248) which probably helps as many people with big straight speed tend to overbrake a bit for T1 which is easy to do. sierra sierra hit 298 on the straight but must lower T1 apex speed than cyber (still around 200 from memory).

[Russman]

That's what aero can do ey. I love how SS and Cyber are so different yet based on the same car. Imagine SS power in the cyber car haha!

[Rowdy]

Hey guys. sorry to dredge a thread (though its proabably about time for an update russ!) but ive been doing a lot of aerodynamics study at uni and i remembered reading about gurney flaps here in this thread...

I thought it might be of some interest to a few guys if i posted what ive found.

There are a number of airfoil shapes out there, and each has its own specific lift and drag characteristics dependant on angle of attack.

A graph i have infront of me right now relates a NACA 23012 airfoil characteristics for instance. It gives values for lift dependant on angle of attack for clean, slotted, or double slotted flaps.

The coefficient of lift for the clean airfoil, i.e. no flaps is 1.52 @ ~15degrees. The coefficient of lift for a single slotted airfoil, i.e. one flap, is 2.67 @ ~12.5 degrees.

so you get an increase in the coeficient of lift of 1.15 for adding one measly little flap.

The flap helps by increasing projected area and injecting momentum into the boundary layers of fluid on the opposite side of the airfoil, which delays separation at any given angle of attack.

now the trade off is drag. the drag coefficient is ~.06 for the clean airfoil, while it is ~.12 for the slotted airfoil.

i fired up my trusty Ti-83 for a bit of a laugh and plugged in the numbers for my rear wing (which incidentaly is russ's old wing) and got some interesting figures.

down force at 100km/h was 390N, or 40kg. The drag at this speed was 18.3N, which equated to about .5Kw power loss.

down force at 180km/h was 1263N, or 128kg. the drag at this speed was 59.1N, which equated to almost 3Kw power loss.

For the same speed, 180km/h, a clean airfoil will produce only 719N of downforce but will only have 28.4N drag force acting on it, or a loss of 1.4Kw.

however these figures are unrealistic because i need to find out what kind of airfoil shape my wing has, and then find the relevant data for that shape. also this is a 2D analysis. still interesting, and the relative differance between an airfoil with and without slotted flaps is clear to see.

anyway, hope this helps/interests someone.

Edited October 11, 2011 by Rowdy

[DJRIFT]

hey Rowdy. just a few questions that i hope are semi basic. or some one may be able to help.

by gurney flaps do you mean the small lid usualy mounted 90deg to the wing or a small 2nd wing blade?

and are you able to tell me on a r32 where to put a wing to get the least drag with the most efficient down force? i realise that i would also be wing design dependent but im working on a car that is restricted to height of the wing (not above roof line) and how far back (rear most part of the body work) and wondering if im better to go with a low lying efficient wing or a wing as high and far back as the rules allow? i know from some testing that high wings are efficient for down force but at what cost of drag.

it may not be a yes no answer but any help would be good.

[Rowdy]

Hey mate,

your question is a difficult one, because i dont know where the flow separation over the car occurs. if it occurs just past the roofline, it is possible that any wing mounted low and forward would be located in a turbulent area. Wings are generally mounted high and to the rear because of this, i would think. high wings mounted to the rear would take advantage of free stream velocity, or air least affected by the cars movement.

as you can see from the calculations above, the drag force was far far below the down force... now admittedly my calculations are not 100%, its just basic aerodynamics stuff, 2D calculations and all that.

the formula for lift, L, is L=.5X(Cl)X(density)X(Velocity squared)X(Area).

the formula for drag, D, is D=.5X(Cd)X(density)X(Velocity squared)X(area)

Where the force is in newtons, density is in Kg/Mcubed, velocity is in m/s and area is in msquared and is the planform area of the wings surface (not the total surface area).

The hardest part to find is the specific Cl and Cd for your specific wing shape, where Cl and Cd are the coefficient of lift and drag, respectively.

anyway i'd say mount it high and back. as for efficiency, if the wing is too effective at providing downforce in this position you can alter the angle of attack to be more shallow.

cheers, Rowdy.

Edited October 11, 2011 by Rowdy

[Rowdy]

oh damn. tottaly got the gurney flap and the slotted flap mixed up haha

sorry, slotted flaps inject momentum, gurney flaps alter the pressure difference.

how embarrassing!

my calculations above where for slotted flapps (of which my wing is a sloted type).

cheers, Rowdy.

Edited October 11, 2011 by Rowdy