Oil canning and skin cracks
FWIW I have no cracks in evidence after 280 hours on our -14A, but....
1. In the 51 years I've been flying light airplanes I have owned several and built three and long ago learned this reality: unanticipated problems always occur and you have to deal with them by first determining your options, evaluating the pros and cons of each and then selecting the best one.
2. In addition to the annual condition inspection I also do 25 and 50 hours inspections of my own design. Each of these includes laying on the creeper and cleaning the belly. But that also gives me the opportunity to inspect all those rivets and stringers too. As I said, so far so good on our airplane but I am confident Van's will come up with a solution to cracking for those who have encountered it. That solution may or may not be applicable to existing airplanes which, like mine, have not had the problem. I encourage builders to await feedback on a Van's solution prior to trying to solve it yourself. As they said, this is not an airworthiness matter.
3. To reduce/eliminate both oil canning and fuselage skin vibration that occurred on our -8A (1700 hours and sold) and -14A, I installed sound and vibration damping panels from Spruce (part number 09-30206). These are effective, light weight and inexpensive. The adhesive backing allows quick and easy installation on the inside of the fuselage in areas with oil canning. They not only stop the noise but also damp skin vibration over a wide area and I'm certain that reduces the likelihood of localized cracking.
Grand Junction, CO
RV-8A N751MB -1700 hours, sold
RV-14A N465MM - 280 hours and climbing