72" U S Propellers Inc

[clhuddleston]

Would love to learn more about my new acquisition, which I first thought might be an incredible reproduction, but have concluded otherwise ... hopefully correctly.

Stamped on both hub and blade:
DES 72C 57
SER 16395
TG 752
EC 18

Red/Navy/Gold decals on each side of prop. "U S" on red star on blue background. Gold sidebars say "Reconditioned by" on one bar and "Approved Station No. 371" on the other.

There is a round 2" "shadow" in the wood adjacent to each decal, presumably from removal of original decals during reconditioning.

Partially obscured but readable stamping on prop:
US
PROPELLER
INC

It appears there is fabric on tips, now repainted bright red. Might not have been red originally. Metal leading edge/tip protectors not removed prior to painting.

Metal leading edges/tip protectors have some dents, but generally smooth, as are heads of screws.

Any help I can get as to age, type of aircraft or engine and type of service would be appreciated. Thanks!

-- C L

[clhuddleston]

Add'l Photo 72" US Propellers, Inc.

Sorry for 2nd thread but couldn't get 2 photos on 1st.

Photo hopefully attached.

-- C L

[Dbahnson]

I've moved the other photo here for clarity.



I'm not at home to look up that number, but it's a common designation nomenclature describing a 72 inch propeller for a small Continental engine (usually 65 hp) with a 57 inch pitch, i.e. "72C57". That's a very high pitch (high angle blade) which would have been used for cruise rather than climb performance, sort of like high gear in a car.

It's likely that it was originally a Sensenich prop and was overhauled by U.S. Propellers, as you suggest. The blanched area looks like the Sensenich outline.

I'll need to check listings at home to see if it was originally a U.S. Propellers design number.

[clhuddleston]

Follow up

Dave, I'm wondering if you have been able to look this up in your database? Thanks!

[Dbahnson]

I forgot to do that when I was home. I've sent myself an email reminder.

[Dbahnson]

Yes, it's a US Propellers design number. See attached images.

[clhuddleston]

Prop provenance and history

Thanks! From the various notes it seems as though it may have been for a 75hp Army Air Corps ship, perhaps at the end of WWI, reconditioned then never placed back in service, as it looks as though it was never re-installed after re-conditioning due to retirement of whatever aircraft would have used it. Are those reasonable conclusions? Do you have any insight about what type of aircraft might have used it? Would it have been on a 75hp Franklin? When mounted on the engine, would there have been a metal "bolt plate" (for lack of knowledge about the proper term) on the front of the prop hub? If so, can such plates be found? Would the attachment bolts have been steel or brass? Presumably hex heads? Would they have been painted? I'd like to mount it on wall as accurately as possible, and perhaps find an old photo of the type aircraft that used it.

[Dbahnson]

I think the "C" in the design number would point to a Continental engine.

There would always have been a steel plate as part of the hub assembly, bolts typically inserted from the rear of the hub so that the nuts could be periodically torqued from the front. Yes, hex nuts and bolts and usually not painted but more often cadmium plated.