Brodhead Pietenpol Association

Original Posted By: KMHeide
Is anyone out there using an aluminum propeller crush plate? Needing a crush plate for my Franklin bolt pattern and not having any luck finding one I had my machinist friend make one for me out of 1/4" 6061T aluminum plate. He chamfered the edges and polished it to a chrome like finish. The perfect touch for the nose of my Piet. This morning I was looking through Tony's "Firewall Forward" for prop bolt information when to my shock I found a paragraph where he say's an aluminum crush plate is okay for VW props but steel should be used on bigger props. Since the bolts are not torqued enough to crush the wood prop hub I would think my plate would be fine. What do you think guys??? After all the work my buddy put into this one I wont have the heart to ask him to do a steel one. Ed G. in Fl.________________________________________________________________________________Date: Mon, 7 Aug 2006 13:02:14 -0700 (PDT)

Original Posted By: Ed G.
Ed,I have 6061T crush plates on my 160HP Cozy Mark IV, 150HP Osprey and 108HP Piete. Each has a wooden prop. With steel washers. Never a problem. One issue though-------you gotta torque bolts on the prop muliple times to get the wood to stablize. I torque down to appox. 90% of final setting, wait a couple days (the apparent torque drops to about 20% below where I had torqued before), then torque up to 95% wait another couple days, do it again until I reach the recommended torque for the size bolts used. Then and only then I safety wire and try the engine. Never have had a wooden prop that remained at the proper torque, by doing it just one time, wooden props are kinda funny, especially if they're new or have been off the engine for some time. Gordon ----- Original Message -----

Original Posted By: Rcaprd(at)aol.com
Subject: Re: Pietenpol-List: Propeller crush platesIn a message dated 8/7/2006 2:25:39 PM Central Standard Time, flyboy_120(at)hotmail.com writes:Is anyone out there using an aluminum propeller crush plate? Needing a crush plate for my Franklin bolt pattern and not having any luck finding one I had my machinist friend make one for me out of 1/4" 6061T aluminum plate. He chamfered the edges and polished it to a chrome like finish. The perfect touchfor the nose of my Piet. This morning I was looking through Tony's "Firewall Forward" for prop bolt information when to my shock I found a paragraph where hesay's an aluminum crush plate is okay for VW props but steel should be used onbigger props. Since the bolts are not torqued enough to crush the wood prop hubI would think my plate would be fine. What do you think guys??? After all thework my buddy put into this one I wont have the heart to ask him to do a steel one. Ed G. in Fl.Ed,The crush plates on the Cont A65 are steel.Chuck G.NX770CG________________________________________________________________________________

Original Posted By:

Original Posted By: Michael D Cuy

Original Posted By: harvey.rule(at)bell.ca
Harvey,I never thought too much about it, but one homebuilt, the Osprey spends it's winters outside here in AK so the prop is removed anyway. I find the 150 hp Osprey big wooden prop needs the technique of torquing the bolts, then waiting, then retorquing in able to get to stablizes each time it's removed before I can finally get the prop bolts to recommended torque and have them stay torqued. The compressed wood, decompresses over the winter and has to be compressed again. Find on the other homebuilts left in hanger in FL that the superheated summer hanger affects the wood's degree of compression. Because I don't have spinners on any plane, it's easy to check prop bolt torque couple times per year and re safety wire. Cozy and Osprey are both pusher homebuilts with prop extensions made of AL and AL crush plates 1/2" thick. Available commercially. All Rutan type canard pushers with through the prop disc exhaust systems have to have these extension, some of these guys are running 180hp Lycos with AL crush plate, so don't think AL is limited to C65's or VW engines.Gordon ----- Original Message -----