Excellent 2 hour vid on how they tested this and arrived at their recommendations: Van's Engineering Presentation: Testing Analysis and Results for Laser-Cut Parts - Van's Aircraft Total Performance RV Kit Planes
Tip: watch at 1.5X speed and slow down at points of interest.
I learned a lot from this. Interestingly, the manufactured cracks at dimples don't seem to propagate.
Now they've established some pretty long airframe life here however we know plenty of things have cracked across all models of RVs in only hundreds of hours in some cases. My feeling from this is that they may have not fully appreciated vibration effects here from the engine and propeller beat though mentioned in 2 areas of the video as acoustic effects. Their take was low stress but high cycles. High stress generally drives crack propagation. Just what is causing many of the cracks that have appeared in RVs historically then?
Tip: watch at 1.5X speed and slow down at points of interest.
I learned a lot from this. Interestingly, the manufactured cracks at dimples don't seem to propagate.
Now they've established some pretty long airframe life here however we know plenty of things have cracked across all models of RVs in only hundreds of hours in some cases. My feeling from this is that they may have not fully appreciated vibration effects here from the engine and propeller beat though mentioned in 2 areas of the video as acoustic effects. Their take was low stress but high cycles. High stress generally drives crack propagation. Just what is causing many of the cracks that have appeared in RVs historically then?
