ERA
R12B/C "Hanuman"

Why it matters

R12B was the third ERA of Prince B. Bira's team and carries the nickname 'Hanuman'. The chassis was rebuilt several times: as a C-type R12C in 1937 and again as B-type R12B 'Hanuman II' after a heavy crash in 1939, which explains the double designation.

How rare is it?

Six separate kinds of rarity – never combined into one number.

Each kind of rarity is rated separately and never combined.

Production

Every figure says what it counts.

Independent counts (e.g. engine and colour) are never combined into a calculated figure. Surviving examples are never presented as original production.

History

R12B was first built in 1936 with a 2-litre engine and raced by Raymond Mays at the end of that season. Over the winter it was rebuilt as a C-type with revised front suspension and hydraulic brakes, and the 2-litre was replaced by a 1.5-litre unit so that R12C was voiturette-eligible. After works drivers used it in 1937 it was sold to Bira's cousin for the Prince to drive and was named 'Hanuman'.

Bira won with it until he crashed heavily in 1939. With no C-type chassis available it was rebuilt to B-type specification as 'Hanuman II'. After the war Bira scored another win before selling it. In total R12B/C recorded 16 major contemporary victories, and in the 1980s the owner built a separate 'R12C Hanuman' from spare parts.

Technical specifications

Engine

Transmission & drivetrain

Chassis, body & dimensions

Performance

“Not yet verified” means no source has been checked for that value yet. Nothing is estimated to fill a gap.

Identification guide

How to tell an original from a replica or later conversion.

The chassis history is complicated by rebuilds: R12B (1936, 2 litre), R12C (1937-39, 1.5 litre, revised front suspension, hydraulic brakes) and R12B 'Hanuman II' (rebuilt after the 1939 crash). The Ultimatecarpage text states that in the 1980s the owner used spare parts to 'rebuild' an R12C 'Hanuman', so two cars carry related identities.

Sources

Each number links to the exact facts it supports.

1. 1
   ERA Club – car information / chassis histories Level B

   • 1 individual chassis R12B/C (one of the twenty cars built by ERA 1934–1952)

   Accessed 2026-11-12