ripple rate proportional to axle cyclic rate would need to avoid frequency components exciting the transmission unfavourablyCraigy wrote: ↑Tue May 07, 2019 7:25 am....Having 100% linear torque delivery to the tyres would be optimal in some sort of closed loop system where a low-latency sensor can detect and vary throttle application to ensure the optimal slip for traction and type temperature, but it'd be hard for the driver to feel exactly where the limit is if the driver was the sensor.....it may make sense to have an element in the transmission that varies the torque delivery in a nonlinear (eg. sine) pattern. The driver can then feel where the limit of adhesion is because every few feet the tyres will breach and retreat from that limit. Such a system might explain this phenomenon: https://www.motor1.com/news/39418/photo ... rol-video/
This sort of thing is used in karting, where electronics aren't permitted in things like braking systems (non-circular rotors and non-circular venting patterns on brake discs are common because they permit feel for where the limit actually is).
The only other reason I can think of why it'd do that would be to deploy energy in the ES via the H. You would pulse the H up, suck in more air, shove it through the engine like in "Q3 free" mode, just for a short period of time to let the ICE climb up into the next few tens of revs each time ...
It would also explain why Honda were having so many problems with instability, if this is their strategy for long straight
I don’t think so. The harvesting relies on allowing the turbine/H/compressor assembly to accelerate increasing its kinetic energy. At 1hz that’s 500msec of acceleration which would increase the revs to well beyond 120000. I estimated a 6000rpm rise in 50msec when this was discussed earlier in the thread.
roon wrote: ↑Tue May 07, 2019 2:54 pmThat sawtooth is also apparent on the left side of the graph. Between T2 and T3 there are some noticeable differences. Looks like one gearshift where HAM stayed flat. The shape of the Honda gearshifts seem slow. Error in graph or was the gear change really so slow? Don't hear delayed shifts in ths video.
How was the graph made? Manual data entry from video reference? Sorry if this has been explained already.
There's pretty much only 1 method possible: OCR (optical character recognition), probably using tesseract software, rendering captured video of the telemetry into still images and then running recognition on all of them. Because the framerate of the video is known you can easily plot velocity against time and so on. With the new F1 app's very clean UI and static background on the speedometers it's now possible to do near perfect recognition with ease, therefore doubting the values in graph itself is pointless.HPD wrote: ↑Tue May 07, 2019 8:34 pmOk, the source is this https://unendinginsight.wordpress.com/
We do not know what methods he uses.
We can see on the Chinese straight, the same pattern.
Bot vs Ver https://unendinginsight.files.wordpress ... vs_ver.png
Honda vs Renault https://unendinginsight.files.wordpress ... vs_ric.png
Edit: He is a reddit user, he uses the F1 App for his data.
The phenomenon seen on the graph has a frequency between 1 and 2 Hz so definitely not synchronous with any rotating shaft in the car.
The data he exports to excel does not include distance so he must integrate the velocity data in excel.henry wrote: ↑Tue May 07, 2019 10:24 pmHaving watched the video I have a couple of questions.
Firstly, I didn’t catch how the lap distance is arrived at.
Secondly, if the method is to extract the data from the on screen data then there is still the question of how the engine rpm get to the screen. Does anyone know how this is done? In fact how does any of the data get there? I don’t have the app.
Agreed. The only grey area is time measurement. The technique assumes the on-screen data is synchronised to real time so if the flow of data is "surging" there will be errors. Those errors would also show in the speed trace so not a likely source for the rpm oscillation.
gruntguru wrote: ↑Mon May 06, 2019 11:41 pmThe average slip at that speed would be in the vicinity of 1% or 2% so a 1% oscillation would be significant.
It would be good if someone more knowledgeable on tyres can chip in here. The tractive force would be about 6.7 kN (assuming 330 km/hr and 600kW). Normal force on the rear tyres would be about 4.5 kN plus aero - say 15 kN total?
2 Hz seems rather like a surge frequency of the car via its transmission of force to ground
I mean tyre slip since I think that amount of clutch slip would kill the clutch, assuming there really is slip.roon wrote: ↑Wed May 08, 2019 11:28 pmBy slip do you guys mean clutch or tire? Not sure what you're accrediting to me, Henry.
Could this be a way to put heat into the rear tires? Cycle tire slip moments on the straights. Maybe VES simply had too many red bulls. Would pulsing the accelerator pedal at 1 hz produce this effect? Without noticeable affect to speed.
In the T2-T3 section of that Verstappen-Bottas graph there are large symmetrical peaks and valleys. If not data error, the trailing sides are odd, assuming they're gearshifts. They should be vertical lines on the trailing side if they were normal gearshifts.
Here You are. The speed/rpm variation is only the first time he is passing the stright(what we see in telemetry as well then). The second time he has better speed and its not variating. So it now even more looks like it is harvesting.