I just can't imagine that the cost of manufacture of the F hub is any more costly than the cost of manufacture of the D1 hub. They will both fit the same rear hub and the blades, and apparently they are not just trying to get rid of old stock, otherwise current orders for the D1 hub would be filled. The only loss with an F hub and non retrofitted blades is the loss of the pitch cylinder, which I never use anyway.
I started out with an early hub. There was a recall on them, and I had to send in my early hub, which was gold in color. Then I received a C hub in exchange that is black. My understanding was that the older hubs did not have sufficient blade clamping action. There was no charge for that change. it just meant down time for the airplane. Since then the have continued to redesign the hub and now have an F hub that eliminates that huge hole that accommodated the pitch cylinder, and seems far superior. So now cracks are developing in the C, and D hubs, so, instead of offering us the choice to go with the new F hub, they offer us a discounted price on a beefed up D hub and call it a D1. Sorry, but I would like to be done with this issue, and I strongly believe that by merely replacing my old C hub front half with the new F hub front half, this problem will go away. I'm not asking for it to be FREE, I am happy to pay the $195. I'm just against sending in my prop, having airplane down time, paying additional shipping both ways for the entire prop, and paying $545 to get it done. I just want Sensenich to send me an F hub and I will be totally satisfied with total confidence in the prop. By the way, I wouldn't be the first to receive an F hub front half as a replacement directly from Sensenich..............Tom