@Revvd
I do agree that there is a disparity between claims, but such disparity is only between old ones (pre-car reveal) and new ones (post-reveal).
I do remember very well about numbers which were hinted during the last couple of years through podcasts or short interviews here and there, and honestly they always did seem to me like some kind of temporary placeholders to give to the media/public to make them happy.
If you just listen to both Newey and Gray after the RB17 reveal, there is no disparity between their claims.
In fact, Newey never mentioned downforce numbers once, focusing instead on L/D efficiency and giving us the 250 km/h mark as velocity limit of confidential tyres for downforce leveling.
On the other hand, Gray did provide the 1700 kg at 160 km/h downforce quote straight away, also basically confirming it twice during his latest interview.
My personal opinion on all of this is that 1700 kg of downforce at 241 km/h would simply not provide the RB17 with a downforce-to-weight ratio (which is what ultimately matters) good enough to match modern F1 lap times.
In absolute terms, the figure itself would be quite high even for race car standards, as it would for example match the downforce of 2017 DTM machines (which were at their peak before they got clipped later on), but there are many race cars in history which matched and exceeded that number.
So, unregulated groundbraking aerodynamics, a 16-17:1 L/D ratio, ground-effect with sealing skirts, a blown diffuser with active fans and F1-banned active suspensions, all of this would be employed just to get to downforce numbers that a 2017 DTM race car was already displaying, at a fraction of the costs and required resources?
Sorry, but this does not frankly add up to me.
Even more, let's play the reverse game and let's assume that somehow that previous quote of 1700 kg of downforce at 241 km/h is true, along with the L/D efficiency of 16.
A quick calc would show that the car would achieve a drag SCx coefficient of around 0.38, which is an absurdly low figure for a car with any form of wings, even if extremely optimized in terms of efficiency like these ones. Instead, going by the claim of Rob Gray (1700 kg at 160 km/h), we would get a much more realistic and credible drag SCx coefficient of around 0.9.
To give even more context, WEC LMH machines are said to have L/D capped to a 4:1 ratio.
By knowing few downforce figures of some of the LMH cars here and there, we can calculate a drag SCx coefficient which would usually fall into the 0.95-1 range.
So, even here I'd say that things would simply not add up if we go by that presumed 241 km/h downforce claim.
Moreover, back to the RB17 being capable of matching F1 lap times, it was mentioned by Newey at Goodwood that Red Bull Racing DIL simulations demonstrated that the RB17 could have taken pole this year at Silverstone with around 1 second of margin over the lead time of George Russell.
DIL simulators are not a game, but extremely complex numerical loops that F1 teams use to prepare themselves for a race weekend and have an as accurate as possible prediction of expected qualifying and race lap times.
Well - if true - such claimed one second faster lap time than the 2024 F1 pole position would basically put the RB17 straight away into qualifying-trim Mercedes W11 territory.
And the W11 is probably the fastest F1 car of all times.
To me, no matter how low the drag, the power-to-weight ratio, the active suspensions and everything else, I believe that 1700 kg at 241 km/h would just simply not give the RB17 the necessary downforce-to-weight ratio to reach such promised performance level.
So yeah - also for all of these reasons - I am personally going to believe into the latest downforce claim from Rob Gray (i.e. 1700 kg at 160 km/h), until definitely proven otherwise with solid data and evidence.
More in general regarding how negative lift is generated, the Time Attack car that you mentioned achieves the vast majority of its downforce by means of insane front and rear wings.
But in the end, downforce is just force [N] obtained from pressure [N/m2]*Area [m2], so simply put you have two ways to increase it: by increasing pressure (on the external wing) or negative pressure/suction (for ground effect) and by increasing the available surface area.
So it's not so straightforward to estimate downforce numbers just by visual comparison.
In fact, the diffuser of a fully ground-effect car can provide a much higher surface area even compared to huge wings of a "traditional" downforce car, hence in the end downforce figures between the two cars could be comparable still.
In particular, the latest version of the Time Attack R8 1:1 (picture below) generates an enormous downforce value of 4800 kg at 290 km/h, obviously mainly thanks to its huge wings.
However, already back in 1979 the Williams FW07 full ground-effect F1 car (see second picture) was quoted to be capable of downforce levels of 2278 kg at 241 km/h.
Just by the mere look of it, would you even say that a 1979 F1 car with such relatively small wings could be capable of such incredible numbers? That's the magic of a race car with its chassis developed from scratch with full ground-effect aero in mind, as majority of the downforce comes from the underbody and not the wings.
And we are talking 1979 here, this is almost "prehistoric" level of engineering and technology compared to what it can be employed on the RB17, especially without any regulation and constraint.
Regarding the Adamastor Furia: I do really appreciate that car and it surely boast interesting downforce figures in race trim. However, with all due respect, are we really comparing it to the RB17?
Come on, it's a no contest in terms of performance targets, applied technology and costs.
On the contrary, the fact that even the Furia can achieve 1800 kg at 250 km/h without blown/active diffuser, outright banned F1-tech, active sealing skirts, active suspensions and bespoke multi-million confidential slick tyres, should once more tell us that such 1700 kg @241 km/h downforce claim for the RB17 should be - IMHO - viewed as an underestimation.
