For several years now we have seen various world championship teams parade, mainly in the Moto2 category, in the Geneva wind tunnel under the responsibility of Professor Patrick Haas.
We therefore took advantage of the winter break to take stock with the latter, both with regard to the recent aerodynamic work of the MotoGP teams, but also on the constantly increased functionalities of the tool which he manages with always the utmost care. same passion.
We thank him for the time he gave us, as well as for illuminating a very technical area with sentences understandable by everyone.
Professor, why do so many Moto2 teams or manufacturers go to the Hepia wind tunnel in Geneva?
“I think it's because with a given budget you have the choice between going to a very sophisticated and very expensive wind tunnel, often for aeronautical or research applications, and not staying there for long, or going to here where it is much cheaper, smaller in size, and where you can really take the time to work in order to obtain the desired results. That means results on the track! Often, it is the group structure that makes the installation expensive. There are often installations that represent significant investments, but which are of little use other than for research. We have a special history in Hepia. We started from nothing, without much means. We have always sought to be pragmatic and we have always had to ask ourselves the question to whom we can sell the use of this or that instrument. Although I have the title of professor, I consider myself first and foremost an engineer. The people who work with me feel the same way. They are passionate about mechanics.
Since our last visit last year, the wind tunnel has evolved, in particular with a new functionality concerning motorcycle radiators...
“Indeed, we have made investments in the field of thermals with the aim of measuring the cooling of radiators at the same time as aerodynamics. So when we do an aerodynamic test, we know at the same time the cooling powers of the object that is in the wind tunnel. This allows you to make decisions, particularly on side fairings, gills and radiator dimensions. Depending on the solutions that we can provide, we know the impact on the cooling of the motorcycle without having to ride on the track and measure the water temperatures to validate the choice of solutions.
The second thing is to then be able to develop much more efficient radiators or to calibrate radiators. Calibration is important because it can then be used in CFD (computer calculation) simulation models.”
Today, in the Moto2 category, is the radiator a real aerodynamic brake?
“Yes, at these speeds, it is clear that it offers great resistance, so there is a pressure difference which is significant. Afterwards, what is complicated is the effect of this pressure difference on the overall aerodynamics of the bike. It's not always what you think and it's not always the radiator that lets air pass easily that gives the best aerodynamics or the highest top speed. But there really is a link between aerodynamics and the radiator. It is an element that is an integral part of the aerodynamics of the motorcycle.”
For the general public, we can perhaps explain that there is an air packing effect at the radiator, that this well-calibrated packing effect contributes to good aerodynamics and that it is not necessary to reduce it too much...
" There you have it. We know, for example, that when teams put adhesive tape on the radiators when it's a little too cold, it can sometimes make the bike faster. It is therefore not obvious that the best radiator is the one which offers the lowest resistance. It’s really an element that contributes to the overall aerodynamics of the motorcycle and that cannot be studied alone.”
So you've invested in a whole system of tanks, pumps and water heating...
“Yes, we are in the process of installing a large reserve of 800 liters of hot water in the wind tunnel which can be circulated with a high pressure pump to the test section. Water will therefore circulate in the motorcycle's radiator during the test. We will also measure the flow.”
Another avenue of work is your ½ scale model of a Moto2. It is now finished. Do the measured results come close to those obtained by computer calculation, and is all this consistent with measurements taken on a full-size motorcycle on the track?
" Yes. Between the ½ scale motorcycle and the one at 1 scale, we can completely transpose the results. It's going very well and we don't have a scale factor. Furthermore, in our wind tunnel, the ½ scale is perfectly suited and the results are very good. What you lose with micro details, you make up with higher quality results in the testing section. It is therefore completely comparable, and also comparable with CFD which has been validated for quite some time. For us, it is also a way to constantly have a motorcycle in our laboratory and to produce cheaper parts since, as they are smaller, we manufacture them using 3D printing. We have also acquired our own 3D printer to be even more responsive.”
We see that this motorcycle is very detailed with its engine made in 3D printing, but also a real radiator in which water circulates...
“Indeed, we can also measure cooling on the model with hot water passing through the radiator.”
Current events require, this model is currently equipped with a four-cylinder Honda engine. Are you going to equip it with a Triumph three-cylinder soon?
" Quite. We will either adapt the model or redo another model, but the engine will be redone anyway, as well as the fairings to adapt to future regulations. We also regularly redo fairings because it is a model which is planned as we do in the world of Formula 1: there is a skeleton on which we attach elements made in rapid prototyping, and it is this skeleton which is instrumented. But everything that is the fairing, the engine, the screen and even the pilot, all of that changes very, very quickly.”
But with this model on which you are constantly working, are you not going to achieve an exceptional result and offer a turnkey solution to the various builders who come to you, instead of letting them progress from their starting point? ?
“We can actually work on our own, without having a team bike permanently here, which would be very difficult anyway. With a manufacturer, it would be easier, but this model already allows us to validate an idea that we might have, before proposing it.”
Since the first bike we saw here a few years ago, the NCS Rapid Inside, the teams and manufacturers seem to parade here, with CarXpert, Tech3, KTM, NTS and a few others in Moto3, Moto2 and even a MotoGP. Why this growing interest in competitive motorcycles, when you also work in many other areas where aerodynamics are important?
“I have always sought to develop our work on very concrete projects that go all the way to the final application. The HES system is entirely in this state of mind even if it is not very common in the Swiss university system. For a professor, it is also a desire to show that he knows how to do something concrete, and not just publish publications on fundamental research. What's also nice is that the stopwatch objectively evaluates the results of our work. It is not a reading committee. This is quite a noble game. It’s a childhood dream to contribute to a bike that wins at Mugello!”
You work with very precise instruments, such as load cells which have a sensitivity of 2 grams while they can measure forces of 300 kg. How can we ensure that the rider lying on the motorcycle in the air stream does not influence the results in any way?
“We are already thinking of developing series of mannequins in 3D printing and in real size, that is to say going into the wind tunnel not with pilots but mannequins, to improve the repeatability of the tests on the development of the motorbike. Working with pilots remains necessary, because it is also training for them, but when we study small things, we need to improve sensitivity. Then, these little things put together make significant, measurable differences. But work is sometimes done on details. A funny thing is that we can see very clearly the qualities of a pilot in the wind tunnel. Some are exceptional, they are able to take over a position very faithfully. The difference in the resistance force measured between two tests can be less than 1 N out of 400 N, even though the rider has dismounted from the motorcycle between the two tests. They are professionals! »
In all the Moto2s that you have seen here, how much can we estimate the difference in speed between the worst and the best, from an aerodynamic point of view?
“On the fast circuits we know, we often managed to get 1-2 km/h better than the second fastest bike. This was particularly the case for Tom Lüthi at the start of the 2017 season. Then it was the case with Oliveira and the KTM at the end of the season. This is important because, with a slower bike, you have to make up for this difference throughout the rest of the circuit, which is quite a frustrating situation for the rider. The difference between the fastest and slowest motorcycle is more than 8 km/h. It is enormous".
In 2016, the Ducati was the most aerodynamically loaded, with an estimated 40 kilos in its maximum configuration. This year, in MotoGP, we saw the appearance of appendages intended to replace the wings. Are there any solutions that you like more than others?
“We feel that Ducati is working a lot. To comply with the regulations, they included the ailerons on the end of the wing. It is therefore no longer a wing which ends in the air but it is a completely faired wing. We also feel that this fairing has been particularly studied to act as leading edge slats on profiles, that is to say things which hold the flow stuck to the motorcycle. There is a bit of a double effect. The bubble has changed a lot too. It seems very sought after.
Afterwards, we also see that they don't use it all the time and it therefore becomes a bit like the world of Formula 1, where we start to no longer have top speed optimization, but circuit optimization. . We no longer optimize things as simple as top speed, but rather lap times. We really do a calculation with models of the entire circuit, and we optimize a solution which offers a low lap time. These are things known in the world of F1 and we feel that they are coming to MotoGP.
We also see that some manufacturers seek to improve the weak points of their motorcycle. So perhaps not all manufacturers are necessarily interested in putting huge fins.”
Are you talking about Honda?
“Yes, their fins are quite modest at the moment.”
Will we soon see aerodynamic appendages in Moto2?
“Yes, I think it will happen very strongly. We know that the Moto2 regulations have been standardized with those of MotoGP, so I think that we will see much more pronounced appendages arrive than what we have seen in the past. It's perhaps less necessary than in MotoGP, but in the end, we still save time. It has often been said that Ducati can have fins because they have a powerful engine and therefore still have a high top speed. This is completely false, we know today that the presence of fins, even if they have a fairly high resistance force, does not reduce the top speed as much as is believed. There is a more subtle effect across the entire bike. Besides, no one saw Ducati losing top speed significantly with the introduction of their fins. We can therefore conclude that the reasoning which says that fins are useless on a Moto2 because the power is low is certainly false. However, their study must be more elaborate. It is undoubtedly on less powerful vehicles that aerodynamics is more difficult!
But fins can be used for several purposes. Like in F1. We had studied tail fins for Dominique Aegerter and Tom Lüthi's bike and this allowed us to go faster. We had managed to work on the wake of the bike. The way it was laid out, it's probably still not allowed, but we have some ideas that we'll definitely get out of the files..."
