Group B cars were banned since January 1987, as well as new-born group S. In spite of the effort of some manufacturers, such as Lancia, Peugeot and Toyota, who already had developed experimental group S cars, and even with most of the drivers support, group S was also finally discarded, and group A cars remained as top-level cars in the 1987 Championship.
B.Beguin/JJ.Lenne, BMW M3, Tour de Corse 1987, 1st
Group A had been introduced in 1982 to promote participation of production-derived vehicles limited in terms of power, weight, allowed technology and overall cost. It was aimed at ensuring a large number of privately owned entries in races. Most aerodynamic appendices were forbidden and only small rear wings or spoilers were allowed.
While BMW M3, Mercedes E190 2.3 16V and Opel Kadett Gsi incorporated simple rear wings, spoilers were more commonly used, although at the end the Championship would be for Lancia, whose Delta HF 4WD lacked any aerodynamic appendix.
J.Ragnotti/B.Thimonier, Renault 11 Turbo, Rallye of Portugal 1987, 2nd
Rear spoilers are used to break air flow through rear part of the car, as the higher the flow, the higher the lift generated. To reduce lift and even generate downforce, spoilers are located both on the rear deck or roof mounted. In some cases, spoilers also help to increase the flow of air below the car, what, according to Bernouilli principle, reduces the pressure below the car, and downforce is thus generated.
T.Salonen/S.Harjanne, Mazda 323 4WD Monte Carlo Rally 1987, retired
Two main parameters define a rear-deck spoiler: height and angle:
– the higher the spoiler, the lower the lift, up to a certain value, normally accepted around 100mm, but it differs from car to car; for longer spoilers, the effect of increasing drag significantly reduces downforce gain,
– the higher the angle of spoiler elevation, the lower the lift, reaching a minimum at around a value of 60º; but drag also increases with the angle.
Spoiler height effect is approximately twice the effect of the spoiler angle of elevation.
Stratissimo/Tonia Pavli, Nissan 200 SX, Acropolis Rally 1987, 11th
Fortunately, Ford broke the rules when introduced the original aerodynamic package in the Ford Sierra RS Cosworth, which was further developed in the Ford Escort RS Cosworth.
K.Grundel/T.Harryman, Ford Sierra RS Cosworth, Monte Carlo Rally 1987, 84th
The history behind the whale-tail rear wing of the Sierra RS Cosworth can be found here.