As part of the 206B main rotor blade fatigue tests conducted in 2015 for FAA certification, Van Horn Aviation created simulated hailstone impacts on a fatigue test specimen. 1.25-inch diameter ball bearings were dropped through a 114.7-inch tube directed to specific points on the blade assembly. This simulated a real-life scenario where blades could experience multiple hailstone impacts. Once all impact points were struck, the blade assembly was attached to the fatigue test fixture and run through thousands of simulated flight hours.
The test data showed that our composite blades can withstand the large hailstone impact under real-life conditions. In many cases where a hailstone impact would permanently dent a metal blade, the composite blade absorbs and deflects the impact, returning to the original airfoil shape and allowing flight to continue. An inspection and tap-test is still needed to ensure no delamination has occurred.