Sling Pilots Forum

Has anybody done a build with flush riveting every exterior surface? From my understanding, the performance difference is negligible, but it would look so good!

What little I know about flush rivets is that they aren't as strong as the surface rivets. I didn't see any noticeable difference between the surface and flush (ie: more flush rivets in the areas where they were used or larger ones), but that was what my understanding is on the differences... again - what little I know about them.

Yeah I would think there is structural component to button head rivets over the flush rivets.

During an RV-15 Q&A session, Vans acknowledged they wont consider using the CS4-4 (flush, countersunk, pull rivets) because they are considered too weak. I don't know if the countersunk rivets used on the Sling are similarly affected. Vans never elaborated much other than saying the flush "isn't even close" to the raised head strength.

Solid countersunk rivets (not the pull rivets) are not affected according to Vans.

It would be interesting to see how the flush riveted Slings are holding up after thousands of hours of service.

BG8473 wrote: ↑Thu Jan 18, 2024 4:58 am It would be interesting to see how the flush riveted Slings are holding up after thousands of hours of service.

I dunno about the Slings, but I used to own a Sonex, which also uses flush pull rivets on the leading edge. That design is almost 25 years old and I've never heard anyone talk about any issues. Presumably the designers know the strength of the rivets they use and calculate the density needed based on it. Or maybe the rivet strength is not the limiting factor compared to other considerations (buckling in compression, etc).