Carbon Fiber (and Owen Bell) To The Rescue
 

Vibration near the rear engine and years of fatigue have caused cracks on the upper lip of the lower tail cap assembly (the panel below the engine with the two holes for the tail pipes). These cracks typically appear at the ring that makes this lip. Repairs are possible and that's what I had when we did the annual in August 2007 (Figure 1 below). But now, eight months later, vibration had taken its toll and the whole area was in shambles (Figure 2). It's evident that these repairs don't last, probably because of the extra stress introduced by the dissimilar strength of the original items and the repairs around it.

Time to buy a new ring. I followed my own counsel in the "Purchasing Parts" page of my www.SkymasterUS.com website and started calling around. A new one approaches $500 and wasn't immediately available. A used one (not my first choice because it's been exposed to the same fatigue, so who knows how long it will last) presented several problems: no one wanted to disassemble the ring out of the tail cap assembly, they wanted significantly more than $500 for the whole tail cap, and all of the available tail caps had repairs. But Don Nieser from Commodore Aerospace was kind enough to tell me that the ring is one of the items that Owen Bell at Aviation Enterprises now makes out of carbon fiber. So I ordered one from Owen and its quality is top-notch.

Two main points here. First, we all are very fortunate to have these two Skymaster specialists, and the dedication they give to our aircraft; they both deserve our support. Second, Owen's list of Skymaster parts made out of carbon fiber continues to grow, is now quite sizeable and the parts are not only better than original but often price competitive with used parts; as a result, I have modified my "Purchasing Parts" Internet page to suggest that you check with Owen before buying used (it had always said to check with Don).

Ernie

Thanks for the info Ernie. I knew that Owen had the CF rear panel but wasn't sure of what all was included. Does it include the rolled ring? Sounds like a nice mod. I was hoping to get Owen to join us at the Kalamazoo meeting but in all my attempts to ask him about attending I have not heard back from him. Glad to hear that you are pleased with his items and I agree that he and Don need applause for the continued passion for our aircraft. If you talk to Owen let's try to encourge him to join us in Michigan.

Owen makes the ring (P/N 1552127-2), which is common to all 337 Skymasters and is where the cracks typically appear. I don't know that he makes the rest of the rear panel.

Ernie

I highly recommend a dynamic prop balance. Without it, vibs will always be a factor.