Hello Guys. I'm planning to mount a lighter Catto 2-blade propeller (Kevlar w/wood hub) on my Pitts S1S to compensate for the extra 45 lbs running the 200hp Lyc. AEIO-360. Craig Catto sent me to Saber Manufacturing to purchase the ½" prop bolts and the recommended longer lugs intended to help distribute the sheer loads on the wood hub. The original lugs sent to me were 3/4" too long to fit into the 1-1/8" gap between the heavy flange andthe case sweet spot. The next batch of lugs were still too long to insert. Saber is currently shortening the lugs further. The lugs currentlyinstalled in the hub are very short and only extend an 1/8" into the back ofthe prop. When the new lugs are installed, they will only extend about5/16" into the hub, but as Saber says, that's better than what I currentlyhave.
Here's the problem: Installing/pulling the lugs through the flange withoutany clearance behind the lug will have to be done by threading a 1/2"all-thread bolt into the lug and pulling it through using the socket routineon the face of the flange. When there's enough clearance behind the lug fora nut, we'll switch to a smaller bolt (take the load off the lug threads)and pull the lug through the rest of the way. That's probably the easierpart...
Our big problem is how to remove the existing lugs when there is only 1-1/8"clearance behind the flange (actually, there's less than an inch clearanceoutside of the 5/8" dia. sweet spot on the front of the case). If I trim asocket to fit behind the flange with room for a nut and washer, we'll onlybe able to back out the lugs approx. half way, and then there's no way toremove the socket. But that can probably be solved by cutting away some ofthe wall of the socket beforehand so that it can be slid past the lugs. So,how do I remove the lugs the rest of the way? One guy suggested heating theflange, then dripping liquid nitrogen into the lug (we have a source) and hopefully freeing upthe lug enough to tap it out with a plastic mallet.
Any input that you can give me will be greatly appreciated!!!
Dave
