PPRuNe Forums - View Single Post - EC225 crash near Bergen, Norway April 2016
Old 28th Apr 2017, 22:36
  #1779 (permalink)  
jimf671
 
Join Date: Nov 2009
Location: Inverness-shire, Ross-shire
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At 1.16.3.11 there is a description of the pattern of compressive stress in a FAG second stage epicyclic gear from OJF. There is no equivalent information for the SNR gear but a statement appears at the final paragraph of 1.6.8.3 that "differences in the finishing process performed by the suppliers can affect the outer race surface residual stress, with FAG having a significantly higher compressive stress at the race surface". The pattern described in 1.16.3.11 seems quite severe in that it appears to have sudden enough changes to be potentially damaging in this operating environment. It would be interesting to know what the equivalent stress pattern was for the SNR gears and the differences in process characteristics.

I wonder where else these factors occur.
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