Hartzell 'K' hub vs. 'R' hub

[panhandler1956]

I plan to call Hartzell about this on Monday, but thought I would post the question in the mean time.

I am preparing to install my new prop (HC-C2YK-1BF) and per the Hartzell manual the 'K' in the model number denotes the type of hub flange. They even put a nice picture in the manual so you can see the difference (see below). In looking at the picture it appears I have an 'R' hub flange. I'm basing this off of the number of holes that are counterbored. The 'R' has only one that isn't counterbored and the 'K' has 2. Looking a my hub flange below, I only have 1 hole not counterbored? Weird. Ok I'm stumped and it's probably really simple....suggestions? The prop is clearly stamped with the K in the model # and all my paper work matches it.

Since the bushings in my crank flange are too long anyway I can't install the prop yet (this engine had a Sensenich on it before). Engine is an IO-360-A1A
I'd like to sort this out before ordering new the bushings.....


Here is my flange with the wrong size bushings installed so I get to press these out and put new ones $$$ in!

[C-GRVT]

I have an AeroSport built Superior IO-360-B1B, and a Hartzell. The engine flange is a "K", the prop flange is a "R". My prop model is HC-C2YR-1BFP/F7497-2.
It seems like your prop flange does not match the prop model number you have.
In the Hartzell manual it says that an "R" flange prop may be mounted on a "K" engine flange (but not vice versa).
Even that seems a bit weird to me as it leaves one bolt in a counterbored hole without a matching flange
It looks like you will need to replace all five bushings that protrude too far, and replace them with what is needed to make the engine flange a "K"or an "R".
Let us know what Hartzell says you should do.
Bill Brooks
Ottawa, ON
Canada
RV-6a finishing

[panhandler1956]

Hartzell responded to my question above:
"Hartzell has not made a true 'K' flange hub in many years. The 'R' flange hubs are used for both the 'K' and 'R' flange installations. You do not need to install 5 drive bushings. If your engine is set up with four drive bushings there is no need to install the fifth bushing."

As for me, since all my bushing are the wrong size, I plan to install 5 bushing that will engage the counterbores and one short (fat) one for the flywheel.
I measured and used the Lycoming 1098 bulletin to determine the correct part numbers and sizes. Ordered them from Tim at Penn Yan - great to work with!

[C-GRVT]

Thanks for letting us know what Hartzell said.
Seems odd that a new Superior engine would come with a "K" flange if that prop flange has not been made "for years".
Bill Brooks
Ottawa, ON
Canada
RV-6A finishing