Originally Posted by
DaveReidUK
i don't think that's necessarily the case. The same principle applies to ice being shed from a blade as does to the release of the blade itself (apart from the vastly different amounts of energy involved, obviously).
In the former case, airframe manufacturers reinforce a relatively small length of the fuselage in the plane of the prop, because that's the part of the cabin that's at risk from ice being shed. Exactly the same applies to the trajectory of a departing blade, except of course that's there's no hope of stopping it if it's heading for the fuselage (which is why it's not supposed to happen).
You make an excellent point; however, I'm not sure that the loads on ice accretions are the same as those on the propeller blades. While the blades themselves have significant fore and aft loads (depending on propeller pitch), ice accretions might not. Ice accretions usually occur initially at the propeller blade root and often extend spanwise (blade span) along the leading edge of the blade toward the tip. My theory (guess?) is that ice accretions, being on the leading edge of the blade, do not experience pressure differentials created by the blade pitch and are primarily affected by centrifugal force. If that is the case, then the ice could be expected to shed within the plane of propeller rotation. Due to the aerodynamic loads on the propeller blade, I would expect that it (they) would shed out of the plane of propeller rotation.
Below is a link to a study titled, "Propeller Icing Tunnel Test on a Full-Scale Turboprop Engine" conducted under the auspices of the FAA (U.S.). I must admit that nowhere in the study was I able to find any specific reference to aircraft propeller ice shedding patterns; consequently, my theory is no more than a somewhat insufficiently educated guess (speculation).
The link:
http://www.tc.faa.gov/its/worldpac/techrpt/ar0660.pdf