=XIII=Wedge
04-25-2010, 09:32 AM
I would like to ask a question about the throttle position and the automatic boost cutout for the Hawker Hurricane and Supermarine Spitfire specifically with a Merlin III engine.
As I understand it the automatic boost cut-out limits the maximum boost pressure by limiting throttle position. Therefore, even if the throttle is pushed to the limit (fully open) the power will be limited to the maximum continuous setting. If the throttle is fully open and the boost control cutout is then activated, enabling War Emergency Power, nothing will happen until the throttle is moved slightly. Then the full range of boost pressure will be available until the boost control cutout control is returned to its normal position.
If the throttle is moved beyond the limit set by the automatic boost control, the boost pressure needle may fluctuate momentarily before returning to its maximum limited value. This is normal behavior.
To avoid this and to set power realistically, the pilot would set normal power using the throttle position, advancing the throttle only as far as necessary to achieve the desired non-WEP boost pressure.
For example, to take off, advance the throttle only as far as necessary to cause the boost gauge to read +6.25 psi and no more.
If WEP is desired, the pilot would first activate the boost control cutout and then advance the throttle fully or to the desired boost pressure.
In real life the red marker on the boost gauge was adjustable. If that is not possible could this be set at +6.25 psi to be consistant with the above.
Can anyone comment on this behaviour in Storm of War - Battle of Britain
Many Thanks
As I understand it the automatic boost cut-out limits the maximum boost pressure by limiting throttle position. Therefore, even if the throttle is pushed to the limit (fully open) the power will be limited to the maximum continuous setting. If the throttle is fully open and the boost control cutout is then activated, enabling War Emergency Power, nothing will happen until the throttle is moved slightly. Then the full range of boost pressure will be available until the boost control cutout control is returned to its normal position.
If the throttle is moved beyond the limit set by the automatic boost control, the boost pressure needle may fluctuate momentarily before returning to its maximum limited value. This is normal behavior.
To avoid this and to set power realistically, the pilot would set normal power using the throttle position, advancing the throttle only as far as necessary to achieve the desired non-WEP boost pressure.
For example, to take off, advance the throttle only as far as necessary to cause the boost gauge to read +6.25 psi and no more.
If WEP is desired, the pilot would first activate the boost control cutout and then advance the throttle fully or to the desired boost pressure.
In real life the red marker on the boost gauge was adjustable. If that is not possible could this be set at +6.25 psi to be consistant with the above.
Can anyone comment on this behaviour in Storm of War - Battle of Britain
Many Thanks