In terms of endurance racing car’s, we have seen a wide range of oddballs among prototypes and GT cars. From the long nose of the early 2000’s Panoz, to the high nose on the 2016 R18 Audi. But most will agree the Deltawing wins the award for the most odd-looking race car to participate in endurance racing.
The Deltawing DWC13 was conceived from Nissan Nismo technical director Ben Bowlby, who set about reworking the new car around the Aston Martin AMR-ONE chassis, a high nose prototype car built by English firm Prodrive, where it raced in the FIA WEC in 2011.
But Bowlby’s concept was going to be used for the outdated Indycar chassis, and not endurance. In terms of technical regulations, the car was a game changer.
But back in 2010, the spanner dropped with a horrible clang. The Governing body for Indycar opted to keep the regulations the same, so Bowlby had to go elsewhere to race his concept. In late 2010, Panoz and Deltawing were granted a ticket to race on the endurance scene.
Over the last couple of years, the car has
been racing in America in the United
Sportscar Championship under Deltawing racing. The car has always showed pace, which mainly excels on the straights due to the small coeffect drag number, on which more later.
Aero approach
While Bowlby had to design the whole car, it had to be adapted to the ACO, so that it could compete at Le mans under the Garage 56 entry. Key changes included removing the front tyre, which was just going to be one fat one, to two narrow tyres, as well as make it a two seater.
Now, let’s take a closer look at this prototype racer. Starting off with the front end, which is just 29.9 inches in width, where the back is 81.9 inches. This would provoke some understeer one would think, but Chief engineer Paul Taylor says ‘’The car is designed around a concept to keep the car balanced in line with the weight distribution, just like any other race car.
There are subtle differences that we come across and work around. The front tyres run on a different part of the track than a conventional race car. We are just as fast if not faster in high speed corners but have a slight disadvantage in slower corners.’’ He says.
While the reduce tyre surface area will affect grip in slow and medium speed corners, the reduced drag and high downforce figure overcomes this as the air speed is quicker under the chassis.
Data engineer Josh Foley adds “The overall aerodynamic package is brilliant and we are extremely quick in a straight line. The downforce figures vary by track, down to 500kilos and close to 2,000kilos and this gives us a lot to play with when it comes to fine-tuning the car for each specific track.
The gains from our design could be a lot higher but we are unable to show the fuel saving when racing as we are limited to a smaller tank, due to balance of performance restrictions and being held to a spec tyre. The important thing to note is that our performance has become increasingly competitive and we have proven that this design can work.”
Over recent years of the car competing well in the IMSA series, the nose saw a splitter with a set of end plates with support rails to deal with the load. Head Mechanic Paul Taylor adds “The splitter is actually for balance to give us more grip on the more twisty tracks with low to medium speed corners. It’s more of a ‘fine-tuning’ piece as we can adjust the amount of extra grip it gives us. We take it off for Daytona as it gives us too much drag on such a fast track, but we need it for tracks like COTA and Long Beach for example.”
Suspension Design
While the main grail upfront was aerodynamically intended with the thin nose, of which slashes the coefficient drag (Cd) figure. This caused headaches for the team’s suspension engineers. In order to pack the front suspension system a full redesign was needed. “The original design for the front dampers come from a design for rear shocks on a mountain bike. As the front wheels are so close to each other there is no room for an anti-roll bar. Over the past four years, we have developed a custom package for the DeltaWing and have seen improved performance” says crew chief Stefan Chistel.
With the suspension seeing all new kinematics to produce as much grip as possible. The team saw help from tyre supplier Continental here also. “The narrow tires mean that there is less touching the surface of the track which does mean less grip. However, we have custom tires from Continental Tire that help us greatly and we have less weight and less drag. It has to be this way for balance of the car, so we couldn’t have bigger tires even if we wanted too” says Taylor.