mosquito64

ENGIN E CONTROL S 120. Throttle controls The black friction nut is for the throttles: the (larger) white one is for the propeller levers. Normally the throttles can be pushed forward to the stops only. When the small catches on the levers are squeezed the throttles can be pushed fully forward. Merlin 25 engines give 4-12 lb./sq. in. boost at the stops and +18 lb./sq. in. when fully forward ; there is no cut-out. Merlin 23 engines may still be fitted. They give +9 lb./sq. in. at the stops and +12 lb./sq. in. at the fully forward position. If the boost control cut-out is pulled, +14 lb./sq. in. will be obtained in low gear. De-rated engines of either mark give +9 lb/sq. in.boost at the stops and +12 lb./sq. in. at the fully forward position, and do not have a cut-out. This be para 20.

From the Pilot manual: System description: 23. Superchargers control When the superchargers gear change switch (51) is set to MOD, the superchargers will remain in low gear at all altitudes. When this switch is set to AUTO the electropneumatic rams are controlled by an aneroid, and will automatically engage high gear when climbing, at approximately the following heights : Merlin 23—8,750 ft. Merlin 25—7.000 ft. These heights are the correct supercharger gear change heights only when using maximum power (operational necessity). When using low power settings, the selection of high gear should be carried out by switching to AUTO as recommended in para. 41. When descending in AUTO, low gear will be engaged at slightly lower altitudes than those quoted above. Failure of the electrical or pneumatic system will cause the superchargers to remain in, or return to, low gear. and Para 41 41. Climbing (i) The speed for maximum rate of climb is 150 knots. (ii) Climb in low gear at 2,850 r.p.m. and +9 lb./sq. in. boost. When the maximum obtainable boost has fallen to + 7 lb./sq. in., change to AUTO. Above 18,000 ft. decrease the airspeed by 2 knots per 1,000 ft. (iii) When climbing for maximum range, climb in low gear at 2,650 r.p.m. and +7 lb./sq. in. boost, using the airspeeds recommended above. When the maximum obtainable boost has fallen to +4 lb./sq. in. set the supercharger gear change switch to AUTO and re-adjust the throttles. Above 18,000 ft. increase power to +9 lb./sq. in. and 2,850 r.p.m. and reduce airspeed as recommended. Although less fuel is used to reach a given altitude by climbing at high power the total fuel used and the time taken on the subsequent cruise is the same, whether the aircraft is climbed at 2,650 r.p.m. and +7 lb./sq. in. boost or 2,850 r.p.m. and +9 lb./sq. in. boost. (iv) When climbing with a boost setting of less than + 9 lb./sq. in. the automatic boost control cannot open the throttle valves fully and the boost will begin to fall off before full throttle height is reached ; the throttle levers should be progressively advanced to the gate to maintain the desired boost. (v) For operational necessity at any altitude, select AUTO and 3,000 r.p.m. and move the throttles fully forward (see para. 20).

I think Squirrel was equating the engines as "pivot points". The important fact that has been repeated several times is that the forces all act through the center of mass not the engines. Hence the left rotation of the aircraft.

Failure to control the various forces under discussion, wanting the aircraft to go left on the takeoff run also leads to an aircraft ground interface. Also known as a sub optimal outcome to a takeoff event. Here's one from 1950 - loss of control during the takeoff (B35 of 14sqdn RAF)