[T2] booster engine

[Jamie]

From: "Robert Mann"
> Quiz Q: why do radial engines have odd numbers of cylinders (per bank)?

Four-stroke radials have an odd number of cylinders per row, so that a 
consistent every-other-piston firing order can be maintained, providing 
smooth operation. For example, on a five-cylinder engine the firing order is 
1, 3, 5, 2, 4 and back to cylinder 1. Moreover, this always leaves a 
one-piston gap between the piston on its combustion stroke and the piston on 
compression. The active stroke directly helps compressing the next cylinder 
to fire, so making the motion more uniform. If an even number of cylinders 
was used, the equally timed firing cycle would not be feasible.[1] The 
prototype radial Zoche aero-diesels (below) have an even number of 
cylinders, either four or eight; but this is not problematic, because they 
are two-stroke engines, with twice the number of power strokes as a 
four-stroke engine.
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