Is there a standard install direction of the honeycomb cells on the Fan Forward case on the CF6-80C2 abradable shroud section?

I have seen engines that the honeycomb cells run point to point front to back. I have seen engines where the cells run point to point in the direction of the circumference of the the abradable material for the Fan blades. I have searched the manuals and I cannot find where the orientation of the honeycomb is specified.

Any repairs are understandably performed with the same orientation. I am wondering is there a MFG standard?


As noticed by Daniel Kiracofe, this applies to the turbine, but as far as orientation is concerned the logic is the same

The abradable material in the honeycomb cells can readily withstand the high temperatures encountered in the turbine stages of the engine and protects the annular steel backing from high temperatures as well as providing a smooth gas flow surface. However, under extreme operating temperatures, the turbine blades may expand sufficiently to actually rub the surface of the abradable alloy overfilling the honeycomb material, whereupon the abradable sealant material will yield so that the turbine blades will not be damaged

However, the abradable material filling a given cell of the honeycomb can become loosened and fall out due to thermal cycling, rubbing of the abradable filler against the turbine blades, engine vibrations, or can otherwise be blown out by action of the hot gas flowing across the seal.

The orientation is the one, the manufacturer found the least probabilistically susceptible to allow the abradable material to separate; internally the cells walls are not strictly perpendicular to their outer flat surface, and this angular orientation prevents to the best the falling of the abradable material. Thus indeed, as you write, the repairs are understandably performed with the same orientation, using identical material.

  • $\begingroup$ This doesn't really answer the question. OP is clearly asking about the fan module and this answer discusses turbine module. Any honeycomb in the turbine module may or may not be oriented the same way as in the fan. $\endgroup$ – Daniel K Jun 23 '19 at 23:54
  • $\begingroup$ @Daniel Kiracofe, Thank you, I will edit $\endgroup$ – user40476 Jun 24 '19 at 7:37

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