Jeff, Bill is correct.
When I found the STC I contacted Executive Sales. They were very happy to help and gave me a copy of the STC. They are MT propeller distributor and own the STC. So if you're considering this propeller I would recommend getting it from them.
Attached is a document from the EAA that Charlie Kohler forwarded to me regarding the 25 to 40 hour flyoff. It is a helpful article to understand the rules that we have to apply too.
Happy flying
Russell Steiner
N2AA soon to be flying!
I don't think that you'd need to purchase the STC. The fact that one existed would, however, put it into the "certificated prop/engine combination", therefore allowing the FAA or DAR to permit a 25 hour flyoff as opposed to 40. Having the STC number and owners information might make it easier for the DAR to accept your claim of a certified combo.
N6ZQ IV under construction
why would you want to purchase an STC?
Jeff
For anyone it's interested in using an MT propeller. I just found a STC for io-550/ MT propeller combination. Now you will need to only 25 hours flight time in the box. The owner of the STC # SA02294CH, is Executive Sales phone number 715-924-4410.