Side pods started appearing in 1970 and evolved through a variety of shapes and functions.
The Lotus 72, raced in Formula 1 between 1970 and 1975, was the first car to incorporate sidepods. These housed the water and oil coolers, which were previously located in the car's nose.
Throughout the 1970's some Formula 1 constructors used varying types and sizes of sidepods, others still placed their radiators in the nose.
By 1979, with the advent of wing cars and ground-effects Formula 1 cars became more uniform. They all looked like the Lotus 78 or 79.
Sidepods extended over nearly the whole length of the car's wheelbase. They housed the all important wing profile and the all cooling radiators.
Nothing can be stored in the nose anymore as the car's fuselage had to be extremely slim so as not to obstruct the underwing's aerodynamics.
Cooling air came in from the front and exited along the top side of the sidepods. The coolers were placed either vertically or at an angle to the incoming air flow.
From 1983 onwards, ground-effects were banned. Initially several schools of thoughts emerged.
The Brabham BT 52 tried the delta form. Ligier's JS 21 tried to do away with sidepods all together. Toleman's TG 183 moved part of the cooling to the nose and small Lotus 72-style sidepods remained.
Mclaren's MP4/1C had the sidepods taper at the back – in the form of a coke bottle. This concept was the one that survives to this day. All other sidepod philosophies were gone by 1985.
The Mclaren sidepods housed the coolers, but their main function was to provide smooth undisturbed air to the all important rear wing and diffuser.
In the ground-effects days the sidepods were producing the bulk of the downforce. Now in the post ground-effects era, they acting as facilitators for the rear wing and diffuser.
Throughout the 1980's sidepods were still relatively large and the taper at the back was not that pronounced. The reason was that the then prevalent turbo cars required extensive cooling, and all that required much space.
From 1989 onwards, after turbos were banned, sidepods got ever smaller, rounder shapes and their taper (or coke-bottle shape) at the rear more pronounced. This design philosophy is still visible today.
In the early 1980's the cooling air was discharged along the top side of the sidepods. By the mid 1980's to the late 1990's the air was discharged along the sides of the sidepods. This minimized the amount of turbulence the hot air produced on the rear wing, and thus improving the latter's performance.
Today's aerodynamically intricate sidepods discharge at the back of the sidepods, causing even less disturbance to the rear wing.
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