[Bug] KM-8 correction mechanism has too large adjustment

[Ramsay]

KM-8 correction mechanism seems too have too large an adjustment range +/- 180°.

 

T.O. 1T-L39C-1 says correction values of +/- 18° are read from the inner scale

 

The default correction at Krymsk is 6° and looks like this.

This differs from the previous description

 

• 
  
• the outer scale - instead of reading the magnetic heading (214°), reads the adjusted heading (220° true) i.e. the same as the RMI compass card after sync.
  
• the thin pointer should be at +6 on the inner scale (10 o'clock position), not +6 on the outer.
  

Because of this scaling error the deviation can be adjusted +/- 180°, here I've set +90°

 

EDIT:

Note: The RSBN needle is stuck to the compass card, the RSBN station is in front of the aircraft on 220° True

 

Setting zero compensation and using magnetic bearings won't work, p̶r̶e̶t̶t̶y̶ ̶s̶u̶r̶e̶ ̶t̶h̶e̶ ̶R̶S̶B̶N̶ ̶n̶e̶e̶d̶l̶e̶ ̶s̶h̶o̶u̶l̶d̶ ̶'̶f̶l̶o̶a̶t̶'̶ ̶i̶n̶d̶e̶p̶e̶n̶d̶e̶n̶t̶ ̶o̶f ̶ ̶t̶h̶e̶ ̶c̶o̶m̶p̶a̶s̶s̶ ̶c̶a̶r̶d̶.̶

 

Edit 2:

 

This looks likely to be the correct behaviour. The English translation of the MiG-21 manual has this RSBN system warning

 

 

and although the western F-5E HSI/TACAN systems use Magnet bearings, it's TACAN needle will read the TACAN station's bearing off the compass card and "drifts" with the card in the event of error/failure.

 

 

Of course TACAN is not equal to RSBN but the two systems are analogous.

 

Still believe the magnetic delineation is read off the inner scale and should be limited to +/- 18° unless ED have pilot feedback stating otherwise?

 

End of Edit 2

 

Tested in version 1.5.3.50487

 

Typical magnetic deviations

Edited April 19, 2016 by Ramsay
Found RSBN needle stuck to compass card is probablly correct behaviour