To quote myself, "RIPPING means the tips have entered the TRANSONIC regime, not that they are supersonic. The air also doesn't travel exclusively in a chordwise flow, but also travels spirally outward from the hub to the tip (slightly). The tips of a 28" prop will actually go SUPERSONIC around 8000 rpm.

Beyond this point the propellor airfoil decreases in efficiency by increasing the occurrence of vortical "shedding" at the tip and wake and also the flow separates from the high-pressure surface, causing the shearing of air along the span of the blade, which increases the noise of the prop.


The "P-Tip" and scimitar props attempt to decrease these factors and result in some noise reduction if designed correctly.