Sense I have Ground Adjustable Propeller
I just got off the phone with Sensnich about their composite (carbon fiber if you prefer) ground adjustable propeller. The propeller was certified earlier this year which might make it an option for our airplanes. I decided to call them and get some information on the propeller to see if it might be possible to do a 337 for my airplane.
Well there is good news and bad news. The good news is that they have a 76 inch two bladed propeller that has been certified by the FAA. It comes with an easy adjust kit which consists of 6 pin sets to easily adjust the blade angle of the prop. If you wanted to mess with a protractor, the blade angles are infinitely adjustable within the range the hub allows. This would allow you to set it up for cruise when you go cross country but if you were going to the backwoods for camping or just wanted to get some STOL flying in, it will take about fifteen minutes to adjust the prop pitch to your needs.
The bad news is a little more nuanced. There are currently STCs for the Lycoming O-360 engines and that is it. They are desperately trying to get it certified for the O-320 series but the FAA between being understaffed and being more gun shy after the Boeing Max fiasco has been dragging their feet on the approval. The other issue is the hubs. Currently they only have hubs for these two Lycoming engines. That is it. No Continental, no Franklin, no nothing (with the exception of some experimental engines like UL Power and Rotax). Finally these is cost which would be approximately $6350 for a certified propeller.
So what is needed to get a prop/hub for our airplanes? Besides the obvious answer of money, it comes down to demand. I have the B4 version of the Franklin 165 which is a six bolt flange. The gentlemen I talked to said it is far more likely that Sensenich will create an 8 bolt hub as they see the utility in that not only for us, but all the airplanes that used the Continental O-300 that had the early 8 bolt flange (C-170s, C-172s, etc). There also needs to be a vibration analysis done on the prop before it can certified (whether that is certification by Sense inch or by you for a one time 337).
According to the man I talked with, there are selling these props as fast as they can make them. He told me to keep talking to Sensenich at every opportunity as the more voices that say they want this prop, the more likely they will do work for us. If the 8 bolt flange on the early Continentals ends up being the same as our Franklins, we need to get together with those groups and constantly bother Sensenich so they see it is worthwhile to make a hub, and therefore a prop, for our airplanes.
I would love to see your comments about this and I look forward to hearing from you all.
Karl A Vogelheim
Thanks for the report. I like the idea but would not spend the $$ for this modification. I would really love to see some clever company start re-manufacturing the Aeromatic system with composite blades. I would be more interested in spending the bucks on something like this.
The prop for the Stinsons with eight bolt flange is the same part number as the 170s and straight tail 172s.
Can anyone tell me if the prop flange for the 220 crankshaft is similar to other engines? It would be ideal if it was the same flange as the Lycoming O-360 but I have no idea where to find that information.
Karl A Vogelheim