A W engine is a type of piston engine where three or four cylinder banks use the same crankshaft, resembling the letter W when viewed from the front.
Napier Lion W12 aircraft engine (circa 1930)
Napier Lion VII
A broad arrow, of which a pheon is a variant, is a stylised representation of a metal arrowhead, comprising a tang and two barbs meeting at a point. It is a symbol used traditionally in heraldry, most notably in England, and later by the British government to mark government property. It became particularly associated with the Board of Ordnance, and later the War Department and the Ministry of Defence. It was exported to other parts of the British Empire, where it was used in similar official contexts.
Ammunition box or coal container dated 1831, displaying Board of Ordnance coat of arms, initials and broad arrow
British convicts in uniforms bearing broad arrows: a late 19th-century print
A broad arrow on a Marconi TF1041B valve voltmeter, indicating Ministry of Defence ownership
An Ordnance Survey benchmark in the UK