Bearfoil
I agree completely with you post this morning, I am impressed as well with this powerplant. As was suggested in a poster's PM I received last night, I did indeed "Google" to search for a patent I recalled, dealing with the advantages of helical spline shaft couplings and the advantages offered over conventional splines. You can see this patent by going to:
Parabolically helical spline shaft coupling - US 5533825 - IP.com
In the background of the invention, it mentions an older reference patent as to how the coupling to a disk is made. This is actually a Rolls Royce patent (US patent #4,292,001) and you can view it by Googling the #. I was curious to see if the IPT disc could be liberated from the shaft at this connection point. Take a look and see what you think.
Regards,
Turbine D