Quote:
Originally Posted by ccsmith51
Probably means a wood prop from Aymar-DeMuth.
|
Yep "A-D" stands for Aymar-Demuth, who apparently was one of the premier wooden prop makers for RVs, Mustang IIs, Thorpes, and other experimentals, before Catto dethroned them.
Both of the guys who ran the company and made these props have now both passed away, and the company is defunct.
Their props are made with about 5 or 6 thick layers of wood (planks) laminated together, and there unfortunately is a bit of history of some them losing blades or large pieces of blades in flight, in spectacular ways. There are also plenty of their props have been in service for years/decades without problems too.
I had several knowledgeable folks look over my prop this weekend and they all concur that the crack is a result of the wood drying out over its 11 years since manufacture, compounded by the fact that a couple holes were drilled into the hub area to insert balance weights, and this likely created a stress zone in the wood. Anyway, what I have now is a 68" long wooden wall ornament. Even if by some far-fetched method, the crack could be repaired by injecting epoxy into it or something, I would never trust flying behind it again.
To "PropMan" Frank: Thanks for the generous offer of a loaner prop. I'm trying to see if I can make my financial situation work out to get a Sensenich composite ground adjustable prop (painfully expensive at the moment) but if that falls thru, you'll likely be getting a call from me. Your props are absolutely beautiful, and I can see that with eleventy-bazillion thin layers of wood laminated and sealed together like that, that there's no way they'll fail in the manner as my A-D prop did.
I know that everybody else here recommends Catto, and if I had a lot of spare time to wait around for delivery, that might be an option too, but the prospect of having stainless steel leading edges, and ground adjustability of the pitch is very alluring on the new Sensenich prop. The WhirlWind ground adjustable prop also looks good, for considerably less money than the Sensenich, but they way you have to manually set the blade pitch with a protractor and trial-and-error just looks like a royal pain, and Sensenich's machined pins method makes childs play of adjusting pitch.