A.P. 129 RAF Flying Training Manual, Part I - Landplanes

[41Sqn_Banks]

Originally Posted by Crumpp

Nonsense, boost override was and was even tested at service inspection. It was not authorized for use except at take off.

The Merlin II/III doesn't have a override for take-off, it only has a cut-out for emergency. A override for take-off is linked to extra rich mixture to preventing detonation. The cut-out does not increase mixture, thus requires higher octane fuel to prevent detonation.

"In combat and emergency other considerations may justify the pilot in disregarding these limitations"

- quoted wrong (it says "restrictions" and not "limitations")
- quoted out of context (the context are time and flight condition limits, not boost limitations)
- quoted comes from a later source (March 1943, thus not related to 1940)

The RAF fanboys would love to see a proof that 87 octane was not required for +12 boost with Merlin engines. No one cares about the type of fuel, it's the +12 boost everyone is interested in.