F1technical.net

I don't really follow the technicalities of IndyCar. Just thought I may try to learn a bit more as FA is competing with McLaren for the 500.

From a technical standpoint, I know it is largely a spec series with the engines coming from 1 of 2 suppliers. What are teams actually allowed to change? How much does the aero vary between street and oval tracks?

trinidefender wrote: ↑

09 Apr 2019, 15:20

I don't really follow the technicalities of IndyCar. Just thought I may try to learn a bit more as FA is competing with McLaren for the 500.

From a technical standpoint, I know it is largely a spec series with the engines coming from 1 of 2 suppliers. What are teams actually allowed to change? How much does the aero vary between street and oval tracks?

Quite a nice technical piece on the actual indycar website showing the differences between Oval and Road Course configurations.

https://www.indycar.com/Fan-Info/INDYCA ... figuration

Also comparing speedway to road/short oval:

Why do they call Gurney flaps "wickers"? Also, interesting that they are required to run the rear wing nose up. So effectively making little / no downforce. Are they just wanting to make the teams run a bit of drag at the rear to help with stability?

Just_a_fan wrote: ↑

09 Apr 2019, 18:04

Why do they call Gurney flaps "wickers"?

I read a book saying the English (not that I'd heard the term before reading the book) steadfastly call them 'Nolders'. It's only a Gurney flap because of Dan Gurney, I find it more interesting that that name has spread beyond motorsport.

Just_a_fan wrote: ↑

09 Apr 2019, 18:04

Also, interesting that they are required to run the rear wing nose up. So effectively making little / no downforce. Are they just wanting to make the teams run a bit of drag at the rear to help with stability?

Nose up doesn't necessarily mean no downforce, the 0 lift condition will be at a fairly substantial nose up incidence. The small camber and blended tip should mean little drag so it's a comparatively high efficiency wing. It's only job is to balance the front wing - for an aerobalance of ~30-35% front.

Actual numbers 33 to 232 lb from min to max angle. Normally Americans quote pounds at 200mi/hr which gives CzS = -0.216 to -1.474m^2, based on that zero lift is at around 9.7deg nose up.

EDIT: Thinking about it the numbers above seemed wrong I'd expect the rear wing to be a quarter of the car's downforce in road configuration - which is only around CzS = -1.25 to -1.38m^2 (car total is ~5 to -5.5m^2). The measurements are pound-force which gives a CzS = -0.0303 to -0.213m^2, which is much more reasonable. The zero lift point is still -9.7deg. Also why do Americans use such stupid units when the entirety of the world uses S.I.???!?

Anyone know what kind of downforce they run now around road courses?

I was reading interview recently and they said that they have lot less downforce with UAK18 kits than individual kits they ran before quote was "several thousand pounds less" What kinda of ScZ are they now? F2 level?

Also is there minimum ride heights in Indycar?

bosanac1 wrote: ↑

22 Apr 2019, 23:17

Anyone know what kind of downforce they run now around road courses?

I was reading interview recently and they said that they have lot less downforce with UAK18 kits than individual kits they ran before quote was "several thousand pounds less" What kinda of ScZ are they now? F2 level?

Also is there minimum ride heights in Indycar?

Cz around 3 using a frontal area of 1.5m^2 (~5000lb-f or 22.24kN at 200mi/hr)

How reliable are those figures?
I am surprised Cz is that high compared to F1.

Thought they didn't make that much downforce.

From what I recall someone mentioned Cz for Mercedes last year was 3.3

When factoring in suspension & tire performance, and mass, downforce figures alone become a less reliable point of comparison. Yaw, roll, and pitch effects not represented, either.

Porsche cooling on IndyCar interest

Talks between the NTT IndyCar Series and German auto manufacturer Porsche regarding a future engine supply agreement have come to light.

RACER has followed the topic with interest in recent weeks as the possibility of signing Porsche to become an official supplier gained momentum behind the scenes. With a new 2.4-liter twin-turbo V6 engine formula due in 2021, IndyCar has held numerous meetings with a variety of manufacturers, including the German auto and racing powerhouse, which are believed to have started in January at Daytona.