Double DRS Mercedes system

Ha sido la gran novedad técnica de esta temporada, si bien parece que no ha conseguido hacer que el coche sea ganador. Mercedes ha introducido esta temporada un sistema que se suele denominar Doble DRS, si bien al principio fue llamado Front Wing F-Duct.

La idea en esencia consiste en “soplar” aire sobre el alerón delantero, para hacer que entre en pérdida, y reducir así la resistencia aerodinámica del coche. Es un concepto que inventó en 2010 McLaren para el alerón trasero, y que fue prohibido para la temporada siguiente, por eso el nombre de Front Wing F-Duct. El aire se obtiene del alerón trasero, cuando el sistema DRS está activo, por eso el nombre de Doble-DRS.

El sistema está siendo “imitado” por varias escuderías, y aunque no lo han utilizado aún en carrera, ya hay una versión mejorada en fase de pruebas, que algunos llaman Triple-DRS, y que os describiremos en la próxima entrada del blog.

Os ponemos aquí un artículo técnico, resumen de varios aparecidos en los últimos 6 meses en scarbsF1, que explica el funcionamiento del D-DRS.

McLaren understood how to stall a wing by blowing a slot perpendicular the wings surface. This knowledge lead to the F-duct in 2010, as you will recall the FIA moved to ban slots in the rear wing and direct driver interaction with the cars aero. But the knowledge of blown slots to stall wings has remained and it’s been Mercedes who have been busy trying to apply it in other ways. This culminated with the tests of an F-Duct front wing late last year (2011).

The open DRS boosted cars top speed and could be used through the lap in qualifying. Despite this benefit the teams did struggle in qualifying, their race performances latterly became better than qualifying suggested. It was clear for Michael Schumacher at Least, that the cars handling wasn’t ideal and the team sought to resolve the cars nervousness.

The DDRS  works to manage the cars balance in high speed turns when the DRS is activated. As DRS reduces both rear drag and downforce, the car becomes unbalanced in downforce front-to-rear. In other words pointy or oversteering. Which in high speed turns in qualifying is hard to handle. At higher speeds even with DRS reducing rear wing downforce, the car has enough downforce to make it around corner, the problem is how to make the car more balanced front-to-rear when DRS is activated.

Driver activation is not allowed, as are any other moving parts to directly alter the airflow. This brings up the Designers favourite interpretation in the rule book, primary and secondary purpose. Any part on the car can be for a primary purpose; sometimes any secondary purpose is banned or restricted. However in most cases the rules are vague and Designers are free to find secondary uses for a solution on the car.

The goal was to find a way to blow into the front wing a duct when DRS is activated, so the DDRS could work synchronously with the DRS.

The hingeplate the flap mounts to, closes a hole when DRS is closed. When DRS is open the duct is revealed and the F-duct stalls the front wing. 

Mercedes has found a way, by creating a duct through the endplate. When DRS is closed, the flap and the plate it attaches to is in a nearly vertical position. When DRS opens, the area the flap initially covered is exposed. If this area featured an opening that lead into a duct inside the endplate, when DRS opened the high pressure above the wing would force flow through the duct. With this duct then routed through the car to the front wing, when DRS is open the DDRS would be blown and stall in unison with the rear wing. Clearly when DRS closes the duct would be closed off and the duct would stop blowing the DDRS, restoring front and rear downforce.

When DRS is open, the duct passes into the beam wing and through the car. Eventually reaching the front wing slot to stall the wing.

 

The front wing has very little form drag. However, induced drag from vortices is produced particularly at the outboard ends. By making the wing more aggressive at its outer ends, means that more vortices will be produced and sent around the front tyre. This flow structure creates drag and stalling the wing, especially near the tips would reduce this drag and boost top speed.