Bug 174 on 12lbs boost. Review please.

[Glider]

looks good to me

[41Sqn_Banks]

- IIRC ABC stands for "automatic boost control" and not the cut-out.

- Spitfire II had "gate control" for fixed take-off boost (it gave a fixed throttle valve setting) and "boost control cut-out" like the Spitfire I, see this thread: http://forum.1cpublishing.eu/showthread.php?t=31319

[fruitbat]

I think 1C will be as stubborn about this as they were about the FW190 bar in il2.

Could you add any indications of the duration for which running at 12lbs / 12.5 lbs was allowed? They would have to model engine damage if the time was exceeded and is essential for any correct FM/DM

[Glider]

The official limit was 5 mins but there was nothing to stop pilots going for a lot longer than that. Dowding issued a memo to all pilots that warned them of overusing the boost. In some of the combat reports you sometimes see words along the line of switched guns to fire, lowered the seat and pulled the plug.

[Osprey]

@Banks: Thanks.
@Stormcrow: Pilot notes specify the limits.

[Bonkin]

Wow. That's a wealth of information that you have accumulated there Osprey.

I have an original Air Publication 1565A "The Spitfire I Aeroplane Merlin II Engine" manual which I thought might be useful - but I think those references you have must cover it all. I went through it specifically looking for performance charts but unfortunately there are none. There are change bars around the fuel and pitch sections though... and it states:

Fuel ....... Specification D.T.D.230
Note:- 100 octane fuel may be used, if the engine has been suitably modified.

Under the Automatic boost control it does mention +12lb/sq.in at sea level but does not tie this to 100 octane fuel.