It’s F1 race weekend again, so I’m back pondering what to do next on my F1 Race Day Strategist spreadsheets. Coming across an article on (BBC F1’s fuel-adjusted Monaco GP grid), I guess one thing I could do is look to try and model the fuel adjusted grid for each race. That post also identifies the speed penalty per kg (“each kilo of fuel slows it down by about 0.025 seconds”) so I need to factor that in too, somehow, into a laptime predictor spreadsheet, maybe?
Note that I didn’t really see many patterns in lap time changes when I tried to plot them previously (A Few More Tweaks to the Pit Stop Strategist Spreadsheet) so maybe the time gained by losing weight is offset by decreasing tyre performance?
One thing the spreadsheet has (badly) assumed to data was a fuel density of 1 kg/l. Checking the F1 2009 technical specification, the actual density can range between 0.72 and 0.775 kg/l (regulation 19.3), so relating fuel timings (l/s), lap distances/fuel efficiencies (km/l), and car starting weight (kg) means that the density measures need taking into account.
Unfortunately, I factored density into some of the formulae but not others, so the spreadsheets could take some picking apart trying to take density into account to keep the different calculations consistent. Hmm, maybe I should start a new spreadsheet from scratch to work out fuel adjusted grid positions, and then use the basic elements from that spreadsheet as the base elements for the other spreadsheets?
Something else that I need to start considering, particularly given that there won’t be any race day refuelling next year, is tyre performance (note to self: track temperature is important here). A quick scout around didn’t turn up any useful charts (I was using words like “model”, “tyre”, “performance”, “timing” and “envelope”) but what I think I want is a simple, first approximation model of tyres that models time “penalties” and “bonuses” about an arbitrary point, over number of laps, and as a function of track temperature.
For the spreadsheet, I’m thinking something like an “attack decay” or attack-decay-sustain-release (ADSR) envelope (something I came across originally in the context of sound synthesis many years ago…)
On the x-axis, I’m guessing I want laps, on the y-axis, a modifier to lap time (in seconds) relative to some nominal ideal lap time. The model should describe the number of laps it takes for the tyres to come on (a decreasing modifier to the point at which the tyres are working optimally), followed by an increasing penalty modifier as they go off.
Ho hum, quali over, so I’ve run out of time to actually do anything about any of this now… maybe tomorrow…?