Can't go past Boost +1 on Beaufighter IF

[lwalter]

According to the flashcards, the Beaufighter IF should be able to reach Boost +4.

Even with 2800 RPM and boost cut-out, impossible to reach more than Boost +1.

What am I doing wrong?

[Plurp]

3 hours ago, lwalter said:

According to the flashcards, the Beaufighter IF should be able to reach Boost +4.

Even with 2800 RPM and boost cut-out, impossible to reach more than Boost +1.

What am I doing wrong?

Boost on.  Lower throttle a little, then back to 100% to reach +4.  If you have some altitude and below +4, then go to S ratio on the compressor (100%)

[BladeMeister]

1 hour ago, Plurp said:

  If you have some altitude and below +4, then go to S ratio on the compressor (100%)

What does that even mean?

 

S!Blade<><

[Plurp]

10 minutes ago, BladeMeister said:

What does that even mean?

 

3 minutes ago, Plurp said:

Turn supercharger to high alt (s ratio) to get back to +4 boost.  Said compressor because digital represenation of throttle/prop/mix has comp for supercharger either 0 or 100%.

 

Edited January 23, 2022 by Plurp

[Buzzsaw]

On 1/23/2022 at 11:10 AM, BladeMeister said:

What does that even mean?

 

S!Blade<><

The Beaufighter's Bristol Hercules engine has a two speed supercharger.

 

Therefore there is a low speed gear, and a high speed gear... the supercharger turns at a higher rpm at high speed.  Called 'M' and 'S' by the British in their manuals.

 

You get best performance, (i.e. higher boost generated) in M gear at lower altitudes.... and better performance in S gear at higher altitudes.

 

You switch from low to high gear at approximately 10,000 ft... depending on the boost level you are running... you would switch at a slightly lower altitude if you are running maximum boost.  Watch the boost gauge... if the boost pressure goes up when you switch, you are using the correct supercharger speed.