help with Prop Blade ID

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Aug 18, 2023
I was recently given two Prop blades from a gentleman who inherited them but had no information on them and I would like to trace a bit of their history.

The blades have part numbers and serial numbers on them ( though the painted drawing numbers have a slight mismatch to the stamped numbers).

Painted numbers on one of the blades
DWG. NO. 6985B-7
SER. NO - 751556
Corr. Angle +.15

the stamped numbers at the base plate of the same blade
DWG NO 6985A-7
MFGN 751554

I have included a bunch of images which probably tell the story better than I do. They are certainly heavy blades and according to the Goodyear Iceguards still on them, they should be Hamilton Standard units. Trawling through what Hamilton Standard lists I could find, they look like the correct part numbers for Hamilton Standard but I have not been able to uncover any details on possible Hubs / Engines or aircraft the blades might have come from.

Any help in identifying the engine and/or aircraft these might have come off, or even some pointers on where I might be able to find the information I seek would be greatly appreciated


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The Hamilton Standard 6985B-7 blade can be used on the Grumman S2F Tracker.

The "JR" number is the distance on the width of the blade butt including the aluminum shank, and the two-steel blade thrust washers. If the dimension goes below that dimensions by more than 0.008 inches, the aluminum blade shank would have to be re-cold rolled to return the fatigue strength to blade.

The "6985B-7" is the blade including the electrical de-ice boot, the "6985A-7" is the bare blade without the de-ice boot.

The Tracker used a Hamilton Standard 43D51 propeller, and a wright 1820 series engine, or the military equivalent series. This series of engine used a different output shaft with fine pitch teeth instead of the much wider teeth found on the stand 50 spline shaft.
Awesome, thanks for the reply. Great to have an idea of what they might have been used on.

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