Bug 174 on 12lbs boost. Review please.

[41Sqn_Banks]

Originally Posted by Kurfürst

On the other hand there is nothing to suggest that 1,40/1,45 ata was not possible use at any altitude. So far I have not found any evidence that this was mechanically restricted to the 1st supercharger speed, and it quite likely that it was not.

OTOH I agree that the manuals insist that is to be used for special take off conditions. Which is kinda parallel to the Spitfire II limitations (which limit +12 to take off conditions only), so it just might be good idea to include a code that this 'WEP' on both planes should be only usable when the wheels are on the ground.?

The take-off boost in Spitfire II was provided by a "gate control" which caused a fixed throttle valve setting, thus boost would fall off quickly with altitude (the throttle valve didn't open progressively to maintain the take-off boost)*.
The boost control cut-out on the other hand opened the throttle valve progressively to kept the +12 boost until it was completely opened, thus emergency boost was maintained up to FTH.

The DB601 manual indicated that for the take-off power the throttle valve is opened slightly more than under normal condition. This would theoretically allow to use 1' Minute boost up to FTH.

* with increasing altitude the throttle valve would again open progressively to keep +9 boost as the throttle lever is logically in the most forward position, but as we know it should only be used up to 1,000 feet this would normally not occur.