Lewis says what we’re all thinking (saying)

Most, but not all of us, have been saying this for the better part of seven years now and it’s never taken root in the decision making in Formula 1 because, in my mind, of two reasons.

Less aero which should beget less aero wake and more mechanical grip for more overtaking. At least that’s our consistent refrain. After all these years, the sport has not changed the levels we feel is needed to achieve this.

With all deference to F1, they have reduced some aero but not enough because teams continually claw back much of the lost aero through crafty interpretation of the regulations.

Reason One

Aerodynamics is the least expensive way to claw serious time out of an F1 car. Sure, it’s expensive but not as expensive as other more radical means like an all-new hybrid engine development program or changing wheel size and drastically altering the entire chassis design. Before you heap scorn on me, I’ve spoken with a few key engineers in the sport who have told me this, I’m not making it up so it isn’t just my silly hunch here.

Reason Two

Teams know that big gains can be made through magical interpretation of the regulation via aero tricks when the FIA makes big changes to the technical regulations. They still recall 2009 when Brawn GP showed up with a dual diffuser and rubbed everyone’s nose in the dirt over a relatively inexpensive stroke of genius. They also don’t want to eliminate their current performance advantages or mothball their enormous wind tunnels they spent millions on.

Reason Lewis

Leave it to our friend Lewis Hamilton to say what other drivers won’t and certainly team boss won’t or can’t.

“There’s been a lot of talk about the rules and whether the drivers should be more involved in decision making,” Hamilton said. “It’s not our job to come up with ideas and we all have different opinions anyway.

“But personally, I think we need more mechanical grip and less aero wake coming off the back of the cars so we can get close and overtake. Give us five seconds’ worth of lap time from aero and nothing will change – we’ll just be driving faster.

“I speak as somebody who loves this sport and loves racing. I don’t have all the answers – but I know that the changes we’re making won’t deliver better racing.”

Good on him I say! It’s great Lewis has the brand equity at this stage in his career to call it out when it needs calling out.

It’s not a popular opinion and I know this but it may be one of the biggest ways to get F1 back on track and fans reinvigorated again.

We’ve done the hybrid sustainable thing and the gimmicky baubles like HD Tires and DRS so let’s try something different for the next 4 or 5 years. What do ya say? It couldn’t be any worse could it? On second thought, don’t answer that.

Hat Tip: Sky Sports F1

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IndyCar – Honda debuts new wing at Detroit

In an attempt to bring the performance of their IndyCar solution closer to the level of their competitors, Honda Performance Development (HPD) has brought a new front wing design to Belle Isle for the Verizon IndyCar Series double-header this weekend, the Chevrolet Dual in Detroit presented by Quicken Loans. The image shown above of the new wing fitted to Graham Rahal’s Honda-powered Dallara was posted on Reddit earlier today. The new design shows a substantial change in the geometry of the outer edges of the wing. Previously, a large end-plate supporting a series of cascade elements occupied the outer real estate of the front wing. Now the cascade elements are curved downward to be partially self-supporting, and an upper canard element as well as the outer profile of the vertical portions of the cascade elements seem to be attempts to divert the air flow away from the front wheels. This is a step away from the primarily downforce-focused initial design and towards a more drag-reducing design as the Chevrolet aero kits are.

Whenever teams and manufacturers are allowed freedom to setup and develop their racing machines differently, there exists the possibility of one team not arriving at as optimal of a solution as others. In Formula 1, we see this all the time, and it leads to one team or group of teams dominating the grid. We saw this with the diffuser solution deployed by BrawnGP in 2009, in the better aerodynamic solution of the Red Bull cars thanks to aero wizard Adrian Newey, and recently we’ve seen the Mercedes power units dominate the 2014 and 2015 seasons. This season, the Verizon IndyCar Series has permitted the long-anticipated manufacturer-developed aero kits for the Dallara DW12 core chassis. Now with different engines and different aerodynamic solutions, Chevrolet and Honda are duking it out not only on the racetrack, but also in the caffeine and doughnut infested confines of their engineering offices. One manufacturer has arrived at a better solution than the other.

Last year, we saw that the Honda motor was down on power relative to the Chevrolet. In fact, Honda-powered cars, in spite of outnumbering the Chevrolet full-time entries 12 to 10 in 2014, managed only six victories over the 18-round season. This season, with the manufacturers bringing their own aero development, the disparity between Honda and Chevrolet is even worse. In the first six races this year, Chevrolet has won five including the Indianapolis 500 Mile Race. The one round in which Chevrolet was not in Victory Circle, they finished in second place. This means that the average top finish for Chevrolet is 1.2, while the average top finish for Honda is a meager 4.2. That number for Honda was helped recently by Graham Rahal who placed second at Barber Motorsports Park and at the Indy Grand Prix and was the highest-finishing Honda-powered driver in the 500 coming in fifth.

Some of the disparity between the two manufacturers comes from teams that have affiliated each. The two giants of Indy car racing, Team Penske and Chip Gannasi Racing, are both using Chevrolet power. Other notable Chevrolet-affiliated teams include CFH Racing and KV Racing Technologies. The strongest team on the Honda side is Andretti Autosport. To be sure, Andretti is a powerful team, after all Ryan Hunter-Reay was last year’s Indianapolis 500 winner. In regard to teams being a regular threat for the victory, Andretti Autosport is about it. There are other quality teams in the Honda camp such as Schmidt Peterson Motorsport and Rahal Lanigan Letterman Racing, but the remainder of Honda teams include mid-pack and also-ran outfits such as AJ Foyt Enterprises, Dale Coyne Racing, and Bryan Herta Autosport. We have certainly seen race winners from these teams, but they’re not where the smart money is on a weekly basis. Regardless of the distribution of teams and talent, however, HPD must do something to close the gap to Chevrolet.

The redesign of the front wing may be a good step forward and be of benefit to the Honda teams, and kudos to INDYCAR for permitting the in-season development in this first year of manufacturer-designed aero kits. Anytime one brings new aero bits to the party, though, there is risk. On a racing machine, especially where aerodynamics are concerned, everything depends upon everything else. By making a substantial change like this to the front of the car, the air flow over sidepods, through the underwing, into the air intake and radiators, and over the rear wing elements are also changed. These changes, which I am sure that HPD has modeled at least through computational fluid dynamics, may work out great, but they may also result in unexpected instabilities and balancing issues. With this weekend being a double-header, the risk Honda is taking is large, but then so is the potential payoff if they’re new kit provides improved performance. I suppose by Sunday evening, we’ll have an answer.

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McLaren front-wing vortices, circa 2003

Academic dissertations conducted in association with Formula 1 teams tend to be subject to multi-year embargoes. Hence, Jonathan Pegrum’s 2006 work, Experimental Study of the Vortex System Generated by a Formula 1 Front Wing, is somewhat outdated, but might still be of some interest to budding aerodynamicists.

Currently an Aerodynamics Team Leader at McLaren, Pegrum’s study concentrated on a front-wing configuration not dissimilar from that on an MP4-18/19 (2003-2004).

A constellation of four co-rotating vortices were created: (i) a main bottom edge vortex, generated by the pressure difference across the endplate due to the low pressure under the wing; (ii) a top edge vortex, generated by the pressure difference across the endplate due to the high pressure above the wing; (iii) a canard vortex, a leading edge vortex generated by the semi-delta wing (‘canard’) attached to the outer surface of the endplate; and (iv) a footplate vortex, generated by the pressure-difference across the footplate operating in ground-effect.

Pegrum shows (in the absence of a wheel, below), that the strongest vortices are the bottom-edge and top-edge vortices, but all four mutually interact in the manner of unequal, co-rotating vortices, undergoing the early stages of a merger.

Now, whilst co-rotating vortices have a tendency to merge, counter-rotating vortices have a tendency to repel. Pegrum highlights the 1971 work of Harvey and Perry, Flowfield Produced by Trailing Vortices in the Vicinity of the Ground, which demonstrated that when a vortex spinning around an axis in the direction of the freestream passes close to a solid surface, it tends to pull a counter-rotating vortex off the boundary layer of the solid surface, (as illustrated below by Puel and de Saint Victor, Interaction of Wake Vortices with the Ground, 2000).

The interaction between these counter-rotating vortices is such that the primary vortex is repelled away from the solid surface. This phenomenon, of course, is still very much of interest when it comes to the Y250 vortex and its cousins.

Source: mccabism

Pirelli: Canada and big, fat slicks

Just as was the case for Monaco, the Pirelli P Zero Yellow soft and P Zero Red supersoft tires have been nominated for the Circuit Gilles Villeneuve: a semi-permanent facility, which combines bespoke sections of track with normal park roads. But Montreal is a very different proposition to Monaco, with much higher average speeds, frequently changeable weather conditions, and a low-grip surface that often catches out even the most experienced drivers. Other important factors affecting the tires in Montreal include braking, with heat from the brakes warming up the tyros (although this year, the behavior of the brakes is different, with the new brake by wire system). There are also some notable curbs in Montreal, which force the tyre to absorb impacts as part of the car’s suspension.

Paul Hembery, Pirelli motorsport director:

“We’re expecting the tyres to be worked a lot harder in Canada than they were in Monaco, with a lot more energy and greater forces going through them due to much higher speeds. This should lead to the maximum possible mechanical grip, which is certainly what’s needed in Montreal. There’s a high degree of track evolution and we frequently see a lot of sliding – especially with reduced downforce this year – which obviously puts an increased amount of stress on the tyre. But we are still expecting to have contained wear and degradation this weekend, even on the two softest tyres in the range. Canada always tends to be an unpredictable race where strategy can make a real difference, also because of the high probability of safety cars. As we saw in Monaco, taking the right strategy opportunities when they present themselves under unusual circumstances is a key element to success at any circuit that falls outside the usual mould, with Canada being a prime example. Historically, there’s a reasonable chance of rain, in which case judging the crossover points – sometimes without previous data, if each previous session has been dry – becomes crucial.”

The circuit from a tyre point of view:

Traction and braking are the two key points that affect tires in Montreal, with the increased torque and diminished downforce of the 2014 cars making the track even harder to master this year. The biggest risk is wheelspin, with the action of the tyres against the track overheating the tread. Late braking can cause flat-spotting if a wheel locks up – however, the design of the 2014 tyres have made them a lot more resistant to this phenomenon.

The cars tend to run a low downforce set-up in Montreal, to maximize a top speed of over 300kph on the straights. The trade-off for this is less aerodynamic grip through corners, meaning that the cars slide more and are more reliant on mechanical grip from the tyre compound to get round the corner.

One of the biggest challenges for the tires in Canada is the fact that the asphalt is extremely inconsistent, made up of a number of different surfaces that offer variable levels of grip. The job of the tyre compound is to smooth out these differences to offer as consistent a level of grip as possible. While Pirelli is nominating the soft rather than the medium tyre alongside the supersoft this year, all the 2014 compounds are slightly harder than their predecessors.

Big, fat slicks

Pirelli have made no bones about their position in doing what Formula 1 wants. After facing criticism over the last couple of years (including this year for their harder tires which were a compromise based upon the new regulations), Pirelli have done a really nice job of turning the Pr and brand management initiative around.

The “we’ll do whatever you want because we’re Pirelli and we can, but you chaps need to figure out what it is want and what you are trying to achieve in F1″ type of statements are a pleasant departure from the forced defense of their position we’ve seen in the past.

To those ends, AUTOSPORT had an interesting article in which they asked Pirelli if they would be willing to look at a tire grip study to go back to wider tires with more grip if F1 removed serious amounts of aero. Hembery said:

“That was one of the things we discussed last year when we first saw the new regulations – having less aero and we’ll give you wider tyres,” Hembery said.

“At the time, the teams didn’t feel that was necessary and wanted us to keep the tyre sizes the same so we weren’t able to follow that.

“But we’ve always said we’ll do what the sport wants.

“If they want us to go up to the old, super-wide tyres we’ll do that; 15-inches, 20-inches – you tell us what you want and we’ll have a go at it.

“But you’ve got to decide what you’re trying to achieve.”

The elephant in the room has always been the insane amounts of aerodynamic downforce generated these days and perhaps, as the article says, Felipe Massa can add to the conversation or at least prompt a longer chat about balancing the cars a bit more toward grip than aero.

Source: formula1blog.com

Nigel Bennett, Gordon Murray, and vortex generators

Erstwhile Formula 1 and Penske designer Nigel Bennett has published a superb autobiography, Inspired to Design, which provides a reminder that several important aerodynamic concepts, prevalent in Formula 1 to this day, were actually invented in Indycar.

One of the recollections in the book even suggests that the use of vortex generators to enhance underbody downforce, was co-conceived by Bennett and Tony Purnell:

“Tony Purnell and I discussed some research he was doing at Cambridge University regarding laser viewing of vortex sheets, an element of which was trying to measure the low pressure generated at the centre of a vortex. Tony explained that if the vortex was trained to run between two plain surfaces, the low pressure would act on those surfaces.

“So, in our wind-tunnel tests, we set out to see if we could use this phenomenon to create more downforce from the car, and sure enough, it worked in that by creating a vortex at the front of the underbody such that it directed air at the underwing and chassis intersection, we were able to gain some 30-40lb [13-18kg] of downforce (full-size at 150mph) without an increase in drag. We developed a series of triangular sharks’ teeth, fitted at an angle to the normal air stream just in front of the lower edge of the radiator intake duct, and the air would spill off these and form the swirling vortex. Later work using flow visualisation techniques showed where this vortex ran, and indeed, other vortices from the outer shelf edge did much the same thing in the outer rear corners,” (p97).

It seems, then, that Bennett and Purnell were the first to systematically investigate and apply vortex generators. This work appears to have been undertaken as part of the design for the 1988 Penske PC 17. However, it should be recalled that Gordon Murray (featured in this month’s Motorsport magazine podcast) introduced inch-deep vortex generators on the underside of the 1975 Brabham BT44, also with the intention of creating downforce. (Murray explains this in diagrammatic form when interviewed by Steve Rider for Sky Sports’ F1 Legends Series).

For those seeking a rigorous insight into vortex generators, Lara Schembri Puglisevich has recently submitted a PhD thesis at the University of Loughborough, reporting the results of Large-Eddy Simulations of vortical flows in ground effect. This work includes a comparison (pictured below) of a vortex generator above: (i) a smooth, stationary ground plane; (ii) a smooth, moving ground plane; and (iii) a rough, stationary ground plane. The images show vorticity isosurfaces, colour-contoured by streamwise velocity. The flow is from left-to-right, with the vortex generator suspended from the floor above.

This is the first attempt to understand the potential interaction between a vortex and the roughness of the ground plane. Unfortunately, it wasn’t possible to make the rough ground plane a moving plane, hence the stationary ground plane builds up its own boundary layer, which interacts with the vorticity shed by the vortex generator.

Nevertheless, these LES images vividly demonstrate just how ‘messy’ real vortices are.

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dd