Old Hartzell Propeller

[Skygoose]

I recently acquired an old Hartzell propeller from a guy who was cleaning out a barn in Missouri. It is in pretty good shape and appears to be pretty old. It has a vintage paint finish on it that shows honest leading edge wear and paint crazing and appears to have been on the propeller when it was in use. Even the decals were painted over but are barely readable through the old paint (which I intend to leave on as it is part of the history of this piece). It is definitely Hartzell; it appears to be walnut; eight holes in the hub; numbers on the side of the hub stamped are "104-56 R.H. SR NO 5568" . I can find no other markings on the propeller anywhere. Hartzell company has been politely unable to provide any further information. What have I got?

[Dave]

I have a list of propellers sent to me by Jimmy Reedy at Hartzell years ago. It has one propeller with those dimensions listed. (Length should be 104" and pitch 56"). In the motor/description column it lists "OX5 Eaglerock EXP. Wyoming". The hub dimensions on yours should correspond to an OX5 hub on this chart.

See if you can post a picture of it here.

[Skygoose]

Thanks, Dave. I'm working on posting some pictures. For now: center hole is 3 1/8" i.d. and the thrust bolt holes are 6 3/4 apart, eight in number.

[Dave]

Then it's not an OX5 engine so my previous assumptions are incorrect.

[Skygoose]

See if these work.

[Skygoose]

Doing a little internet research I tend to agree that it is from an Alexender Eaglerock. These aircraft were produced in Colorado from 1925 to 1932. Looks as though many had a red and grey paint scheme (like Cubs are known for "Cub Yellow") which could account for the sporty paint job on my prop. Photos of these aircraft show propellers of the same shape and form as mine. Thanks for the input.

[Dave]

Doing a little internet research I tend to agree that it is from an Alexender Eaglerock. These aircraft were produced in Colorado from 1925 to 1932. Looks as though many had a red and grey paint scheme (like Cubs are known for "Cub Yellow") which could account for the sporty paint job on my prop. Photos of these aircraft show propellers of the same shape and form as mine. Thanks for the input.

Many propellers resemble each other but are totally different applications. The listing I have indicates that it was made for use on an OX5 engine, but your hub measurements don't match, so I'm skeptical that it's the correct assumption. The bolt hole circle for an OX5 engine should be 5 1/4". I can't explain the discrepancy, however.

[Skygoose]

I'm not sure what to think about the OX-5 dimension differences as well. Your reference materials indicate Eaglerock for the 104-56 dimension but what do you make of the EXP OX-5 and the Wyoming reference? Alexander aircraft was in Colorado if I am not mistaken.

[Dave]

I don't know what that all means, but in general propellers were built for specific engines rather than specific aircraft, so usually when you see an engine specified it's a pretty good bet that the hub was made with that engine's specs. You hub "looks" too big for an OX5, even if it got drilled for something else. But whenever you see "EXP" stamped on one it's even more difficult to know what they were doing.

[Skygoose]

I contacted Udvar Hazy at the NASM and received information that indicates that Packard 1A-744 has the same dimensions as the hub on my Hartzell Propeller: 3 1/8 inch diameter center hole; eight mount holes on 6 3/4 centers one half inch in diameter.

[Skygoose]

I have a list of propellers sent to me by Jimmy Reedy at Hartzell years ago. It has one propeller with those dimensions listed. (Length should be 104" and pitch 56"). In the motor/description column it lists "OX5 Eaglerock EXP. Wyoming". The hub dimensions on yours should correspond to an OX5 hub on this chart.

See if you can post a picture of it here.

Dave:
Could you provide me with a copy of Mr. Reedy's document that references this propeller? I'm still continuing my research. Thanks.

[Dave]

I'll see if I can find it. It's buried with a lot of other trivial data.

[Skygoose]

That would be really cool if you could find that reference from Mr. Reedy. I have learned that Alexander Aircraft did have a distributor in Wyoming which might possibly account for the Wyoming reference. They were also a CAM (contract air mail) operator. This is an interesting project.