IV Rib Construction

[Kahle76]

It seams odd that the verticle section of the main ribs are made in two pieces with the break centered on the opening for the rear spar. Is there a structural reason for the break or is it to optimize material?

Thanks, Mike

[HighWing]

Mike,
Back when Skyster filed their bankruptcy and all operations were shut down, we tooled up for making ribs to support the existing fleet. I checked some of the ribs we made and they are the same. I suspect there is some slight material saving but not likely significant. It was probably due to ease of fabrication. The shear web or vertical portion was hand routed using a template. In that area the template, if made of wood as ours were, would have been rather fragile. I suspect the engineers determined that adding the strength of the shear web at that point, if continuous, would not have added significant strength to that provided by the inch wide cap strip. Today I understand the shear web is laser cut so I suspect they are continuous, again for ease of fabrication. Not sure on that. Others with experience with the newer models would have to chime in here.

[Kahle76]

Thanks Lowell