Bug 174 on 12lbs boost. Review please.

[Kurfürst]

Originally Posted by 41Sqn_Banks

A higher "emergency" boost than the rated +9 was definitely used from 21 August 1940 on, there are combat report and ORBs that proof this.

http://www.wwiiaircraftperformance.o...3aug40-orb.jpg
http://www.wwiiaircraftperformance.o...1aug40-orb.jpg
http://www.wwiiaircraftperformance.o...g40-orb541.jpg
http://www.wwiiaircraftperformance.o...-21aug40-1.jpg
http://www.wwiiaircraftperformance.o...-21aug40-2.jpg

Note that none of these papers ('proof') specify any kind of boost rating. They merely say they used max. power. And max. power was +9.

Kurfürsts has the theory that the whole squadron called the regular climbing/rated boost of +9 boost in this instance "emergency boost". However he didn't came up with an explanation why they would do this.

Because that was the maximum allowed for the Spitfire II as demonstrated.
Its no more than an awfully silly theory that when pilots made reference to emergency power, they meant using an emergency power far above the sanctioned limits for emergency power.



In contrast 41Sqn_Banks has the theory that a reference to emergency boost *MUST* refer to +12 lbs, even though +12 lbs is not listed anywhere, not referred to by any pilot, report or manual.

I'd like to see the reasoning why it is so certain that a reference to the emergency rating refers to a higher than +9 lbs boost. I call it wishful thinking.

What he didn't came up is an explanation why would the Spitfire II manual lists +9 lbs as maximum combat boost (whereas the Spitfire I manual lists +12 lbs.)

Note that this reports explicitly mention "emergency boost" and don't mention "emergency power", the later could be interpreted as the normal "All out" setting of +9 and 3000 RPM, which was only allowed for emergencies. But as this is not the case it's clear that a boost higher than +9 was used in this instance.

All this is playing with the words, assuming a random rating which is not listed anywhere.

It's simply your assumption that the mention of emergency boost or cut out refers to +12 lbs.

My assumption is that emergency boost simply refers to the +9 lbs combat limit, which is underlined by the fact that this is the limit specified by the manual.

You are welcome to prove that emergency boost allowed for greater than +9 lbs, in the summer of 1940.

There are also other reports from November 1940 that show the use of the boost control cut-out. The use of the cut-out only makes sense to increase boost beyond the rated +9 or when there is a failure in the boost control.

http://www.wwiiaircraftperformance.o...son-2nov40.jpg
http://www.wwiiaircraftperformance.o...en-30nov40.jpg

Problem is the maximum rating allowed was +9 lbs.

There's a logical failure in your assumption that the boost cut-out would increase boost beyond +9 lbs. Its quite likely in fact that the pilots obtained +9 by using the boost cut-out, as on the Spitfire I.

Fact is that the Spitfire I manual of the era lists +12 as the limit, obtainable with the boost cut-out. When Spitfire I pilots refer to using the boost, they sometimes specify the boost used as well (+12).

Its only logical that since the the Spitfire II manual of the era lists in contrast only +9 as the limit, it would mean that when Spitfire II pilots refer to using the +9 boost, w/o specifing the boost used and referring it in vague terms like 'emergency boost'.

P.S. Curious, isn't it, that there's not a single hint or tests for +12 Spitfire IIs isn't it.

But if we are going down the road of fantasy boosts that are much higher than the limits listed in the engine/aircraft manuals, I want my 1.7 ata 109E, too. Even though if the manuals say something completely different. Hell if official limits are to be ignored on Spitfires, we might as well ignore them on Messerschmitts as well, and come up with whatever fantasy we may like.