original question: what Piston configuration is the Piston engine that is the Variation of [Rolls-Royce Merlin I]?
answer: v12 engine
answer type: Piston configuration.
auxiliary information: Rolls-Royce Merlin I engine was the first variant of the Rolls-Royce Merlin engines produced.
When it comes to the Variation of [Rolls-Royce Merlin I] what Piston configuration is the Piston engine?