English is not Stella's first language, and I think his word choices are slightly skewing the meanings.
By saying "beyond calculation", he's not saying that they didn't try to figure it out, but rather that they did not succeed in figuring it out. As you suggest, there is no way in the world that McLaren would have overlooked the effects in principle, but they were unable to model those effects accurately enough when they were designing the car.
I believe that wind tunnels that can replicate and measure aero forces under yaw are a relatively new development. The MTC wind tunnel was state-of-the-art when it was built, but unfortunately that was about 16 years ago.
"Another category" is just (I surmise) how an Italian would express "another level". As I read the quotes from Stella, they reminded me of interviews with Valentino Rossi.
Wow … Yes so the problem appears to be that McLaren have fallen behind on the wind tunnel tools, equipment, sensors etc. The old adage of worker blaming tools does not apply here …
Did the engineers ask for advanced cornering dynamic wind tunnel tools and up to date CFD? Were the requests refused?
If not requested then engineering incompetence, if they did ask, then management incompetence. Truth somewhere in between?
This won't be a quick fix a process for continuous systemic improvement needs to be put in place.
INSIGHT: F1 WIND TUNNEL TECHNOLOGY REACHES AMAZING NEW LEVELS
BY: JAMES ALLEN
12 FEB 2018*
Here at JA on F1 we like to take readers’ questions direct to people who know the answer. That’s how the original FOTA Fans Forum started in 2010.
We had this question about the level of sophistication of F1 wind tunnels and we put it to Professor Mark Gillan, formerly chief operations engineer at Toyota and Williams in F1 and a leading expert on wind tunnel development.
His answer shows how amazing the level of technology has become – with teams even able to introduce exhaust flows into the testing model – but also raises questions about how there is this whole side to the sport which is hidden away and secret.
Question: What do you know about or have heard about centrifugal forces research in F1? What if any differences are there between a stationary wind tunnel model. A rolling road wind tunnel model and a engine running, wheels turning wind tunnel model/actual car.
Hell, it keeps bikes running upright as if they have a ghost rider. There’s a strong force there. It has at least been looked at? Is there any exploitation of it in F1?
Prof Mark Gillan’s answer: Recent developments over the last decade in motorsport wind tunnel testing have been transformative.
However it should be noted that some of what goes on within an F1 tunnel facility is somewhat artificially directed by the restrictions in facility usage (via the F1 regulations), especially with regards to model size (now at 60% max scale in F1 through regulation), speed, wind on time, number of runs and tunnel occupancy.
During the last decade there has been a dramatic push in the following areas:
i) Aggressive application of enhanced efficient wind tunnel testing methodologies, including continuous motion systems, high speed data acquisition analysis, with ultra-quick model changes;
ii) Shape, aeroelasticity and turbulence intensity matching of model scale to full scale;
iii) True cornering studies with proper interference correction methodologies;
iv) Steel belt rolling road systems with eccentric wheel drive units for tracking tyre contact patch movement and measuring wheel lift through the belt;
v) Real time robotic flow visualisation and automatic minimal interference full flow field interrogation;
vi) Remote health monitoring of facility and Key Performance Indicators (or KPIs) tracking tools.
So to specifically answer your reader’s question; over the last decade the wind tunnel model testing process has transitioned from fixed steady state single ride height, yaw and steer systems to fully dynamic continuous motion models, integrated with high speed balances, pressure sensors and acquisition systems that map the entire operating envelope of the car within a few minutes of wind on time.
Typically this sweep is done with a roof-mounted hexapod system (see below)
The rolling road systems and integrated boundary layer bleed systems not only give a more realistic flow field around the car – particularly in the diffuser region – but also allows you to measure wheel-lift through the belt using the eccentric wheel pads that sit underneath the tyre contact patches.
The teams can also run pseudo exhaust flows using integrated pneumatic systems or on board high speed electric motors.
There are even attempts to represent cornering manoeuvres, but this activity and process is secret.
As the teams drive their continuous motion systems faster and faster they do come up against limits and inertial effects play into this.
The teams then feed these complex multi-dimensional aero maps (measured in the tunnel) into their driver in the loop simulators.
The simulators help the teams better understand the importance of transient effects and stability criteria though performing “what if” studies.
These studies help drive the weighting criteria and KPIs in the tunnel and pinpoint what the test programme should include.
With each week F1 wind tunnel testing becomes more advanced, more dynamic and more realistic, with continuous improved correlation between CFD, the tunnel and the track.
How the hexapod works
The picture (courtesy MTS Systems Corporation) shows a modern F1 rolling road set up with hexapod, fairing strut which connects the hexapod to the 60% model and the rolling road itself.
The top of the fairing strut is aligned with the ceiling in the wind tunnel so the hexapod is completely hidden in the ceiling. The hexapod provides 6 degrees of motion for the model and forces and moments are taken from an internal balance that sits inside the model and is about the size of a large shoe box. To be exact whilst the hexapod can provide yaw motion, yaw is actually provided by a separate drive unit under the driver’s helmet in order to keep the faired strut aligned with the air flow in the tunnel and to have minimal blockage.
The model sits on a 1mm thick steel belt that is driven by the rolling road via a set of rollers. These rollers also steer the belt to ensure that it is not ripped off by the side forces that are generated by the wind tunnel model. The speed of the belt is the same as the airflow and the boundary layer ahead of the belt is removed using suction plates and then re-injected aft of the road. The belts range in sizes but modern rolling roads are over 3m wide and about 9m long.