Bug 174 on 12lbs boost. Review please.

[Kurfürst]

Correction: Spitfire II limitations for BoB were +9, not +12.

See:

[Robo.]

Originally Posted by Kurfürst

Correction: Spitfire II limitations for BoB were +9, not +12.

I am sorry but you're wrong. +12 was used in Spitfires Mk.II during BoB.

[Kurfürst]

Originally Posted by Robo.

I am sorry but you're wrong. +12 was used in Spitfires Mk.II during BoB.

And the source for that..?

[41Sqn_Banks]

The use is reported on:
- 21 August 1940 http://forum.1cpublishing.eu/showpos...postcount=1441
- 2 and 30 November 1940 http://forum.1cpublishing.eu/showpos...8&postcount=55

The page from the Pilot's Notes is from June 1940. Spitfire II entered service on 13 August 1940.

[Kurfürst]

Originally Posted by 41Sqn_Banks

The use is reported on:
- 21 August 1940 http://forum.1cpublishing.eu/showpos...postcount=1441

Only mentions "emergency boost", at 4000 feet, does not specify boost used/obtainable.

- 2 and 30 November 1940 http://forum.1cpublishing.eu/showpos...8&postcount=55

Only mentions "boost cut-out", at 4500 feet, does not specify boost used/obtainable.

The page from the Pilot's Notes is from June 1940. Spitfire II entered service on 13 August 1940.

And the point is?

+12 lbs boost was only usable for take off and at low altitudes, and it fell of rapidly, in contrast to Spitfire I pilot notes which notes its effective up to rated altitude. There was no 'two different' sytems on the Spitfire II during BoB.

See:

[41Sqn_Banks]

Originally Posted by Kurfürst

There was no 'two different' sytems on the Spitfire II during BoB.

AP 1565B, Vol I, Section 8 was issued in August 1940 and mentions the "two different" systems. "6. The quadrant plate has a ... gate for the throttle lever in the take-off position". And in paragraph 7 mentions that the "red-painted thumb lever can be pushed forward in emergency".

[Kurfürst]

Originally Posted by 41Sqn_Banks

AP 1565B, Vol I, Section 8 was issued in August 1940 and mentions the "two different" systems. "6. The quadrant plate has a ... gate for the throttle lever in the take-off position". And in paragraph 7 mentions that the "red-painted thumb lever can be pushed forward in emergency".

They are the same. The throttle had a section for takeoff gate postion, and the "Red painted thumb lever" covered that position as safety switch, physically preventing the throttle to be pushed into the take off position until it was pushed forward.

Hence the confusion. The manual itself does not describe any two different systems.

[41Sqn_Banks]

Originally Posted by Kurfürst

They are the same. The throttle had a section for takeoff gate postion, and the "Red painted thumb lever" covered that position as safety switch, physically preventing the throttle to be pushed into the take off position until it was pushed forward.

Hence the confusion. The manual itself does not describe any two different systems.

Please explain how the red painted thumb lever was able to physically prevent the throttle to advance into the gate position.

[Kurfürst]

Originally Posted by 41Sqn_Banks

Please explain how the red painted thumb lever was able to physically prevent the throttle to advance into the gate position.

In the override position...?

Use your imagination a bit where that little thing just above the "Push" sign goes when the red painted thumb lever is rotated back. Yup, it prevents the throttle from being pushed into the takeoff gate.

[JtD]

+12 lbs boost was only usable for take off and at low altitudes, and it fell of rapidly, in contrast to Spitfire I pilot notes which notes its effective up to rated altitude.

Now how would they technically do that, make the boost of 12" drop off quickly instead of having it follow the outside pressure? What did the automatic boost control cut out do on the Spitfire II if not disable automatic boost control?