Feature Focus: Rear Wing Endplates

Chevy revealed their Aero Kit for the 2015 IndyCar season on Tuesday at IndyCar media day. The release saw some interesting design and technical features on the car.

Photo: GM

In an earlier post, I talked about and gave an overview of the new features on the car compared to the Dallara chassis the teams were running last year. This time, we’ll be taking a look at a specific feature of the Aero Kit that is new to the IndyCar series, grilled endplates. 

Endplates are vertical elements attached to the rear and front wings of the cars on either side (see image above). For this feature, we’ll just be taking a look at the specific function and implementation of endplates on the rear wing, and using the Chevy Aero Kit as our reference. When the Honda Aero Kit is released, a new article may be written depending on how different the designs really are.

The main uses of the endplates are to decrease drag and manage how the air flows around the wing element.

To decrease drag, the endplate controls how the air comes off of the wing and directs it along the wing tip vortices. Much like an airplane, this streamlined air creates less drag than if the air wasn’t funneled to a specific point before it came off of the wing. It creates less disturbance in the air, decreasing the drag of the car. The endplate acts with the car just as a winglet acts with an airplane:

Endplates work like winglets do on a plane.
Photo: The Fly Engineer

The endplates also help to manage how the air is moved around the wing and hitting the other elements. Teams can better manage down-force levels and achieve the proper performance from the car with endplates. It gives them another mechanical device besides the wing itself to tinker with. They help the car cope with the airflow over the wing and direct its path.

Depending on how much leeway IndyCar gives to the teams in terms of modifying the endplates and wings, they could be changed every race as a part of the setup to achieve the proper down-force. It will also be interesting to see how Chevy changes the endplates for oval courses as compared to the road setup. One thing you can be sure to see is a change in the size and number of “grills” on the actual endplate. 

IndyCar’s endplate (2013) vs F1’s. Note the grills on the F1 car.

As you can see from the image above, IndyCar has always had smooth endplates with no grills (also known as slots) on them. On the contrary, Formula One has been seeing grills on the cars’ endplates for many years now. The grills play a vital role in equalizing the pressure above and below the wing.

Without the slots, the two pressure zones would collide and run off of the wing, creating turbulence and increased drag on the car. The slots help to equalize and bring the two different pressures (high and low) together before they exit off of the rear of the wing tips. 

Air pressure moves towards the outside of endplates.

The high pressure air traveling over the wing moves toward the slots and the edge of the car due to the lower pressure air that is on the outside of the endplates (just as gas diffuses in a room, moving outward from the source). This creates a gradual reduction in the pressure and smoother airflow when it comes off of the wing.

 As I said before, it is possible to change the both the size and number of slots on the endplate, and I suspect Chevy will make those changes with the speedway kit.

If the actual size of the rear wing changes, more slots would be needed to achieve the same affect. The greater the area of the wing, the greater the pressure difference between the inside and the outside of the wing.

The more grills in the wing, the more air is diffused out and less pressure is left on the top of the wing, the less down-force the car has. So, at a speedway like Indianapolis, the Aero Kit may have more slots in it to reduce down-force in order to gain more speed. This assumes the speedway Aero Kit has a rear wing of the same dimensions as the road/short oval one does. If the wing is smaller to start with, then teams won’t need the extra slots because the wing itself will do the job of reducing down-force just by taking up less area. 

If you have any questions on endplates and the slots on them, or want to know more about another feature of Chevy’s Aero Kit, let me know in the comments below or on Twitter!

First Technical Analysis: Chevy’s Aero Kit

Chevy revealed their 2015 Aero Kit on Tuesday.
Chevy released their 2015 IndyCar Aero Kit design on Tuesday at IndyCar Media Day.
Photo: GM/Chevy

The Chevy IndyCar team revealed their Aero Kit for the 2015 season on Tuesday at IndyCar Media Day. Honda has yet to show off their plans or any images of the car.

A collection of photos from the release as well as a breakdown of the parts and design features can be found below. 

The Design 
Chevy revealed their 2015 Aero Kit on Tuesday.
Photo: GM/Chevy

Chevy revealed their 2015 Aero Kit on Tuesday.
Photo: GM/Chevy


Chevy revealed their 2015 Aero Kit on Tuesday.
Photo: GM/Chevy
The main differences between the Aero Kits and the previous Dallara IR-12 that was used during the 2014 season are as follows:

1. The front wing has new “uppers” that were not previously featured on the car. They are mounted on a pedestal in front of the end plates. These essentially work like the front and rear wings do, increasing down-force on the car without adding too much drag; they have a very thin and streamlined profile. 

2. The “wheel wedges” that we saw last year are back again, but with a slightly different shape in front of the tire. They are much smaller and do not attach directly to the side pod like we saw last year, they are separate and further back from the pod. This reduces the overall profile of the car and cuts out some extra material weight. 

3. The overall shape and size of the car, specifically with the engine cover and side pods, is reduced. This is due to a newly designed turbocharger and exhaust system that is smaller and more compact than last year’s. This will increase aerodynamic performance, especially on the large ovals such as Indy.

4. The “top flick” element is also new to this year’s cars. This feature wasn’t on the 2013 model; there was nothing on top of the “bumper pod.” This plays a role in aerodynamic down-force on the car (more below).  

5. The rear “end plates” are grooved and feature grills instead of being solid as they were last year. This does cut out some weight but could hinder some aerodynamic performance with disturbed air getting caught up in the grills; more on this.

6. The “bumper pods” are larger than they were last year, coming up above the rear of the wheel. This will again increase safety and make it even harder for cars to drive up onto the back of one another. They also have the “top flick” on them. The pods are not directly attached to the rear wing.   

7. The “upper flick” and “main flick” are two new additions to the car. Just like the top flick, they are essentially holes for the fair to pass through without creating a tremendous amount of increased drag while increasing down force. I wouldn’t be surprised if the “oval” version of the Aero Kit has smaller “flicks” to get rid of some of the down-force it’s creating. Their specific use will be further detailed in an upcoming post.

That’s all for the first technical analysis of Chevy’s 2015 Aero Kit; a breakdown of the major parts and changes on the car compared to last season.

More articles will be posted about specific features of the car and more in depth looks and “technical analysis” for mechanical and design aspects of the car will show up, too.

If you have any questions about the technical aspects of the car or what the new parts are for, let me know in the comments below or on Twitter

We’re waiting on you now, Honda. 

James Jakes’ Sole Podium Performance

James Jakes piloting his Acorn entry during the 2013 season.
Photo: 3D Car Shows

James Jakes will drive for Schmidt Peterson Motorsports (SPM) for the 2015 IndyCar season. The team announced Jakes as their second driver on Monday to partner with James Hinchcliffe.

Jakes raced in the IndyCar series in 2013 with Rahal Letterman Lanigan Racing. The 2013 season was also the year when the Englishmen secured his first and only podium in the series.

The podium came in the form of a second place finish at Detroit in the second race of the doubleheader event. Jakes qualified in second and led four laps on the way to taking P2 behind the Frenchman Simon Pagenaud. 

Jakes raced all 19 races that season but was only able to secure 19th in the Driver’s Championship; he had a season high of 12th place in the standings after Belle Isle. 

James Jakes will be competing in his fourth IndyCar season when the 2015 season kicks off on March 29th in St. Petersburg, Florida. 

Is Reliability Really Improving in F1?

Felipe Massa crashed his Williams machine during the 2014 German GP.
Felipe Massa crashed his Williams machine during the 2014 German GP. — Photo: Reuters

Mechanical reliability in Formula One is always a struggle for teams each year.  FIA, the governing body of the sport, reworks and changes the rules for the teams to follow each year.

Just going from the 2013 to 2014 season alone, there were huge changes to the rule books concerning the cars. The switch from V8 to V6 engines, decrease in fuel allotment down to 100kg, and fixed ratio gearboxes were just a few of the aspects of the sport that the FIA decided to change.  Whether these changes are good or bad, that depends on who you’re asking.

Nevertheless, the teams have to conform to them and update next year’s car based on them. With that, you get uncertainty in the performance of the car due to the limited testing sessions in the Formula One off-season.  There are only a few opportunities for teams to test out the changes they have made before they have to get the cars to the grid at Melbourne for the season to start.

But are teams getting any more reliable than they were in the early 90’s?  Are they able to adapt better, quicker, and use the testing sessions early on in the season more efficiently to eliminate mechanical failures?

A look at mechanical failures by year shows that, in short, reliability is improving overall as time goes by.  The numbers shown are percentages of mechanical failures by year, starting with 1992.  They were calculated by taking the total number of mechanical failures of a given year and dividing it by the total number of possible finishes if every car finished every race, (the total).  

Crashes, racing incidents, and disqualifications were not included because they do not have anything to do with the mechanical reliability of the car.  If a crash was caused by a brake failure or other mechanical issue, then it was included. 

Number of mechanical failures, by year.

As a whole, the percentage of mechanical failures is decreasing.  In 1992, there were 130 mechanical failures which is about 27% of all the finishes, an enormous amount by today’s standards.  Last year the sport saw just 27 failures, or about 6.4%.  That means that in 2014, there were 20.6% less failures than there were 23 years ago.  

By looking at the data, you can also see the spikes where unreliability drastically improved or decreased.

 2002 to 2004 specifically saw a large drop in mechanical failures.  It went from 29% to 17%, a drop of 12 points, in those years.  The reason?

Parc Ferme.

This rule was introduced at the start of the 2003 season and limited the work teams could do on the cars after qualifying started.  Prior to the rule being implemented, teams could have a qualifying and a race setup ready to go on the car.  Once qualifying was over (where setups built for speed would be used), race setups would go on (built for longer stints, better tire wear, ect.).  

Parc Ferme stopped this practice and limited the teams to performing very minor adjustments such as changing the tires and small setup tweaks.  With teams having to focus all weekend on one setup for qualifying and the race, reliability improved. 

They had all their attention working on one car for the race, not diverted to multiple setups, and reliability benefited greatly the next two years as teams came to grip with the new rule. The percentage of mechanical failures has never come close to the 29% it was at pre-Parc Ferme rule, an attribution to its success in that department.

Kimi Raikkonen pulls into Parc Ferme after qualifying.
Kimi Raikkonen pulls into Parc Ferme after qualifying. — Photo: Mirror UK

Another time that we saw a big change was 2005-2006.  This was when the FIA and Formula One decided to switch from V10 to V8 engines to limit the increasing engine power levels.  With the new engine in place, teams had to do some major re-modifications to their cars.  

Along with those changes came changes in reliability.  Failures rose from 11% to 18.2% for the 2006 season, a 7.2 point increase.  This was a significant rule change and teams were not as successful at implementing them as they had been previously with the V10’s.

2014 saw a plethora of new changes to the rule books.  Just like 05′-06′, these adaptations saw an effect on the performance of the cars.  High up on the laundry list of adaptations was the engine switch, this time from V8’s down to V6’s.  

There was a 6.6 point increase in the number of mechanical failures from the prior year, climbing up to 13%.  The engine wasn’t the only contributing factor, though, new aero regulations, tire weight, and the switch from KERS to ERS all no doubt had an impact.

2015, however, doesn’t have many changes from 2014 in terms of rules and car specifications that need to be met.  This should mean that reliability rates increase (lower in percentage) for the 2015 season. 

McLaren Suffer Cooling Pressure Issues at Jerez

The McLaren MP4-30 suffered a technical failure on Tuesday.
The McLaren MP4-30 suffered a cooling pressure failure on Tuesday.
Photo: Eurosport

McLaren was forced to retire from the third day of testing at Jerez after a cooling pressure failure on the car.  The team managed 32 laps in the morning session making day three their most productive yet.

The problem forced McLaren to take the engine out of the car, ending the day’s testing session.

“We’ve had a loss of cooling water pressure and have removed the power unit for inspection. That’s a long process, so it ends today’s running.”

The MP4-30 was being driven by Fernando Alonso when the problem occurred, according to a statement earlier today. 

“The issue was promptly spotted by Fernando on an outlap – so quick to trace,” the team reported on Tuesday.

No further details were given concerning what caused the failure, but the team is confident they will be able to run tomorrow for the final day of testing at Jerez.

“We can replace those components ahead of running tomorrow.”