Cowling Crack

[1964-M20E]

I found a crack on the metal angle that runs on the lower portion of the stock cowling on the pilot’s side.  It has been repaired with a doubler however the other side has the same thin that was already repaired with a doubler.    I did not see anything like this on my former E model and there is not evidence of it on the 65 parts plane I have. 

 

I went back to the photos that I took when I purchased the plane and I could not see the crack in the photos.  I plan on keeping an eye on this an not that worried but would like to have an idea of why it occurred.

 

Has anyone else seen the type of crack on the original cowlings?

 

[N601RX]

My F has 5800 hrs and I don't have any.  It may have had a out of balance prop at some point that contributed to the cracks.

[takair]

Do you have a photo? Mine had a crack on the internal former on the copilot side, side panel. It would actually make an odd drumming noise during mag check. Added doubler and noise gone. I suspect it is just from air pounding on it inside and out. That skin is quite thin, as is the former.

[N601RX]

John, I was wrong, I do have a crack and doubler in about the same place. Its close to the cowl flap hinge bolt, so the the cowl flap may have put some extra stress in that area. Is yours in the same area? Sent from my iPad using Tapatalk HD

[1964-M20E]

Ysjut aout the same location on mine.

[takair]

I was thinking of the wrong area. I was just working in that area and did not see any cracks. From John's photo, it looks like the front of the cowl is preloaded down. In the original cowl design, there were screws rather than quarter turn fasteners......and more of them. I suspect that made for a more rigid structure. Also, looking at the photos I don't see the bracket for a bolt between the upper cowl and lower. On earlier models they had this as well. All a real pain for working on the plane, but perhaps this added rigidity when assembled?