On the Merlin 20 series, the maximum boost available in case of the cut off engaged was regulated through bleed holes of a particular size - which at least required different cut out valves. This way the cut off no longer disabled the abc completely, it just reset it to a higher boost level.
The take off setting did not use the mechanism of the cut out valve, but went a different way, the particulars of which I don't remember right now. It essentially is a fixed throttle setting around the abc as opposed to an abc controlled boost, managed through varying throttle settings depending on a pressure balance. The boost limit with engaged abc cut off and the boost limit with the take off setting are not related.
The necessary modification for the Merlin XII when using all out level with 12lb boost would be a modification of the cut out valve.
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10-14-2012, 12:48 PM
Hybrid Mode
