The Lotus 20 is a Formula Junior car built by Lotus for the 1961 season as the successor to the Lotus 18. It paired a spaceframe chassis with fibreglass bodywork and was sold with a choice of gearboxes.
Lotus 20 at a glance
| Introduced | 1961 |
|---|---|
| Category | Formula Junior |
| Predecessor | Lotus 18 |
| Chassis | space frame |
| Body | fibreglass |
| Front suspension | double wishbone |
| Rear suspension | lower wishbone, fixed-length driveshaft as top link |
| Brakes | Alfin drums, later discs at the front and inboard drums at the rear |
| Engine | Cosworth Mk.IV |
| Gearbox | Renault Dauphine or Hewland-modified VW |
| Variant | Lotus 20B |
Based on one source (English Wikipedia).
History of the Lotus 20
Compared with the Lotus 18, the 20 had a much smaller frontal area and a lower centre of gravity. The driving position was reclined so far that the driver was almost lying down, where in the 18 he sat more upright. The chassis was a spaceframe clothed in fibreglass, with double-wishbone front suspension and a rear layout in which the lower wishbone worked with a fixed-length driveshaft used as the top link.
The car was originally fitted with Alfin drum brakes at all four corners, soon upgraded to discs at the front and inboard drums at the rear. Standard equipment was the Cosworth Mk.IV engine, and buyers could have either a Renault Dauphine gearbox or a Hewland-modified Volkswagen unit.
The 20B was mostly the same car but with a sway bar and standard inboard drum brakes at the rear. Some 20Bs ran with the Lotus TwinCam engine and so raced outside Formula Junior, in Formula Libre and series such as the Tasman championship. Two Lotus 20s were entered in the 1965 South African Grand Prix for Dave Charlton and Brian Raubenheimer, but Charlton failed to pre-qualify and Raubenheimer withdrew after his clutch broke in practice. A 1962 Lotus 20 hangs from the ceiling on the first floor of the Canadian Automotive Museum.
Design and features
- Small frontal area: a much lower and narrower shape than the Lotus 18.
- Reclined driving position: the driver lay almost flat to keep the centre of gravity low.
- Fibreglass body: light panels over a spaceframe chassis.
- Choice of gearboxes: Renault Dauphine or Hewland-modified Volkswagen.
- 20B specification: rear anti-roll bar and inboard rear drum brakes.
Lotus 20 versions
- Lotus 20 (1961): the standard Formula Junior car with Cosworth Mk.IV engine.
- Lotus 20B: with sway bar and inboard rear drum brakes; some ran TwinCam engines in Formula Libre and the Tasman series.
The 20 succeeded the Lotus 18 and shared its approach with the sports-racing Lotus 23. More racing cars are in the Lotus collection.
Sources
- Lotus 20, English Wikipedia: design, specification, 20B, 1965 South African GP
