hamilton standard props
 

ladies and gentlemen, can anyone please explain to me why hamilton standard made the prop blades on Navy P-3s rounded at the tip and the tip blades on legacy C-130s squared?? Excuse me if this question has been posted previously but any insight into the differences would be greatly appreciated.
thank you in advance.

Kind Regards,

In another life in another century I flew the L-188 Electra, and if my memory serves me properly there were two types of prop available for the Allison at that time. One was Aero Products and had square tips, the other was Hamilton standard with rounded tips. I think the last AP props went out about 1976, so they are probably thin on the ground now. At the time they were preferred over HamStans, can't remember the exact reason, but rumoured runaway prop incidents may have contributed.
;)

I'm guessing the rounded tips would produce a smaller vortex at the tip. A prop is basically a spinning wing and you have a pressure differential on the front and back-sides, and a spill-over on the tips which form the vortices.

The aero products props are hollow so the square tip is required to seal the end of the blade. The Ham standard props are solid so they can have a more efficient rounded end. The aero products props are about 120 lbs lighter but do not perform as well and are less damage tolerant.

The Britannia turbo prop also had two types of props

The 102 with slightly less powerfull engines had hollow square end steel props
The 312 with more powerfull engines had round tip solid dural props

However when the steel props became rare the 102 also started to use solid round tip props as long as matching engines had them say 1 & 4 or 2 & 3

Also the Lockheed Constellation also in some types used hollow steel blades which had round tips

Yes, Hamilton Standard all, if I'm not mistaken, manufactured under license by deHavilland Propellors (later, became HS Dynamics).