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.