Rainbow Spar Load Testing Video

[Bartman]

Ron posted this video a little over a year ago.

Ron owns Rainbow Flying Services, he holds STC's for a series of wood spar products that are widely viewed as an improvement over the factory design. His website is here
https://rainbowflying.com/

 

[Bartman]

watching it all of the way through, it looks like Ron's making a few different points...the compression cracks/failure are the primary failure mode for how the spars are designed/loaded, the expanded plywood doublers distribute the loading sufficiently to prevent the compression failures prior to ultimate failure along the grain (which is unavoidable if you load it enough), and even with splits along the grain the spars will still fail in compression at the top of the spar just outboard of the doubler plates and strut attach points before they fail along the grain from the existing cracks.

very interesting video and kudos to ron for making it. he's a brave guy to be standing with his face right in there while testing those spars!