In my case, it's because the original inspiration came when following a McLaren around the track - and it has an airbrake setup instead of a DRS. Also, with my power/weight, drag is less of an issue than braking.

rharris19, thanks for the real-world race results. While you were using a different wing, it sounds as if you found the same things I did with regards to stability.

 

It must be nice having enough power to say drag is less of an issue. Unfortunately for my stock 1.6, power to weight is a huge issue on the straights.

 

I was genuinely surprised that it lasted the entire 24 hours with no issues. The cord for our wing is only 7.5" long, where the COT is 11" IIRC. I would suspect that it would be best to use two motors, like you and Jack did, with a COT wing. The braking felt great with the wing we have, but I can imagine might feel better with the COT wing.

It will be getting another 16 hours of testing this weekend at our regular track TWS, so we should be able to get some decent data in the dry. We are so familiar with TWS that we should be able to pick up pretty easily where it is helping. I will let you guys know the outcome.

 

i told you so.... you need bigger brakes.

 

Junk data can live forever on the internet. So I did some more testing, and here's a comparison between two runs on the front straight at WSIR, one (red) with the wing going to low drag on the straight, and one (blue) with the wing remaining in a fixed position. The rear ride height sensor wasn't working, so this shows the front, which drops down when the rear wing is switched to the low drag position (note: the line going higher on the graph means the nose of the car was moving lower to the ground).



So that would seem to show that leaving the wing in the high-downforce (high drag) position on the straight meant losing ultimate high speed.

But then here's the flipside. This is the same two laps, but looking at the back straight. This time the high drag (and high downforce) speed starts out slower, but then catches up to the low drag run -- which doesn't make any sense, if the low-drag position is lowering a significant amount of drag.



The difference could be as simple as the prevailing winds during the two (sequential) laps. Or one of many other factors.

So the jury is still out.

 

Maybe raising the nose is decreasing the drag from the front splitter/airdam area as you get to higher speeds?

 

It would appear that the No-DRS (more rear downforce) mode results in a lower nose height, as opposed to creating a cantilever effect which lowers the rear and raises the front. That is assuming that the ride height y-axis is arranged with height increasing as you move up the graph.

Jack -
Were the tests performed as a full lap with DRS engaged then a full lap with it disengaged or was the DRS-ON lap only activating it on the straights, with the wing in downforce mode for the rest? If it was activating just on the straights, at what point on the track did you engage it for the sample on the back straight? Between 5 and 6 or after 6? If before 6, is your car downforce-dependent over 6?

And you're right, WSIR gets windy enough to probably wreak havoc with small sample-size testing.

-Ryan

 

I believe the nose was coming down when the wing was moved to low-drag. But I don't remember right now which direction on the graph is up and which is down. I haven't used that data since building the wings, so I'm rusty on it.

On these two laps, I was either engaging the DRS on the straights (red) or leaving the wing in the upright position for the full lap (blue). You can see on the first graph's ride height line where the wing changes position (at least, that's what I'm assuming the divergence of the two lines means).

On the back straight (the second graph), not much is clear at all. But again, it has both pronounced elevation changes and is less 'straight' than the front straight.

 

Actually looking at it again, the y-axis must be the opposite of what I thought at first - height must increase as you go lower on the graph since it's almost certain that the ride height decreases as speed increases considering that you do have front aero.

-Ryan