Originally Posted by
riff_raff
However, the total cost of manufacturing and retrofitting a dozen or more gears would likely run several hundred thousand dollars per gearbox. So the question becomes is that cost worth the added safety/reliability provided?
Do you really think the benefit of the new material would be spent solely or even at all on improving safety or reliability?
Given that designers and manufacturers would probably apply the same design methods, same approach, codes and practices, same safety factors and design inputs, would they not simply arrive at either a smaller lighter component or increase the design loads on it or increase the TBO on the gearbox?
With limited experience of this new material in service, might they not risk getting caught out by the unexpected at least as much as they have already been with the 16NCD13 gears on the L2 & H225 when performance is pushed to the limit?
Is there not a statement in the conclusions section of the NASA article you linked that there was significant variation in fatigue performance (“However, due to considerable scatter in the UHS test data, the anticipated overall benefits of the UHS grades in bending fatigue have not been fully demonstrated”).
The benefits of new wonder materials will only be realised when consistency can be guaranteed. How consistent I wonder is the 16NCD13 material and the present planet gear's manufacturing processes?
Last edited by Concentric; 17th Jul 2016 at 07:06.