Composite or Carbon N1 Fan Hub
If N1 fan blades can be made of composites - why can't the fan hub/fan disk also be made from composite/carbon fiber etc.
A large engine N1 disc is a hefty piece of metal of around 200 kg at a guess. Surely there is a lot of weight to be saved.
Some other items that I can think of that are still made from metals - by why can't they be carbon/composite as well
- landing gear legs
- Engine pylon struts . These items are rather heavy. If they can make a wing spar from carbon, why not these bits.