Hartzell "Liberty" propeller

[guam2250]

Gentleman,
Back in 1998, I purchased a, possibly never mounted (no visible indentations from a metal hub plate in the wood, no dents in copper sheathing on tips), at an antique flea market. This prop is identical to the photo gallery Liberty prop #2684 for Liberty engines, 1917

Prop info:
length - 115"
hub thickness - 6-1/2"
center hole - 3-1/8" dia.
bolt circle - 8", 8 bolt holes
wood - walnut, copper sheathing on ends
Liberty decals
numbers and symbols - 2 Navy anchors, "1", "2", # 2832

I contacted Mr. James Reedy at Hartzell to help identify the prop and he sent the forms to be filled out. The first identification form came back with manufacture date of 4/5/05. On reflection, Mr. Reedy felt that date was incorrect and sent another form with the date 1924. Both forms showed the prop was intended for a Curtiss D-12, 435 hp engine, installed on a Martin MO-1 observation plane. The Martin Co supplied me with photos, including factory assembly with some props leaning on a wall, but they are a different shape than the Hartzell Liberty.
The hub dimension chart shows this prop went on a Liberty 8, 290hp, 1700rpm engine. The chart photo also says 1917 for the # 2684 prop.
In the "Story of Hartzell Walnut Propellors" , published by Hartzell, there is a copy of a 1919 letter from Loening Aeronautical Engineering Co. This letter references 3 airplanes fitted with Hartzell Liberty props, one US Army and two, US Navy.

Questions:
1) Wouldn't my prop, #2832, be closer to the 1917-1919 years for manufacture?
2) Couldn't my prop have been intended for one of the Loening monoplanes built for the US Navy?
3) Does anyone have drawings or photos of the front metal plate the would have been mounted on this LIberty prop?

Sorry to be so long winded on this posting. Any help would be greatly appreciated. Thanks, Mark

[Dave]

I wrote a letter many years ago to Jimmy Reedy, while he was still working at Hartzell, and he called me right after he got the letter, excited about the decal. At that time he told me the history that when Hartzell first began manufacturing props for the government they used the "Liberty" logo decal but that they very soon afterward were forced to change it due to a trademark dispute with the manufacturers of the Liberty engine. If that was correct, then those props with that decal were likely manufacturered some time in the 1917 - 1919 time period. He told me that there were only 4 propeller designs that had that logo but did not know what aircraft they were used on.

Can't help with the metal hub. Sorry.

[guam2250]

Hartzell Liberty

Dave,
Thanks.

I think I have this mystery solved. The Hub Dimension chart shows that my "Liberty" 6-1/2" thick hub was designed to go on a Liberty L-8 engine. From the Smithsonian Annals of Flight, Volume 1, Number 3, I found that the General Motors manufactured L-8:

" Like the L-4 and L-6, the L-8 was a victim of competition with a tried and proved engine, in this case the Hispano-Suiza-300. The L-8 was also the victim of a more serious problem: vibration. This was so serious that production was stopped at the Buick plant when a total of 15 had been built."

Since my "Liberty" prop was designed for an engine that was taken out of production, it would seem logical that my prop was apparently set aside, never used and somehow, eventually wound up in a flea market in Richmond, VA. One of these days, I think I will make it into a rather large, but slow turning. ceiling fan. Thanks for your time. - Mark

[guam2250]

Navy anchor

Dave,
What is the significance of the Navy anchor symbol? Does that mean the prop was intended for a Navy contract, in general, or a specific design using the L-8 engine that didn't happen, due to the engine problems? Thanks for your time. - Mark

[Dave]

I think it simply indicates that it was made under a contract with the Navy and intended to be Naval property.

A word of caution - the matching of hub dimensions to dimensions on the chart DOES NOT necessarily mean that the propeller was used with that engine, as other engines may have the same dimensions. Those dimension are more useful for eliminating possible engines and establishing a higher probability that it was used on a specific engine.

[guam2250]

What do you think about the info and opinions I have on this Hartzell Liberty?....the unused condition, L-8 engine etc. Appreciate your time, Mark

[Dave]

I wouldn't infer much from the unused condition. Most of the propellers from that era that have survived are either ununused or were damaged and removed as unairthworthy, but most are surplus. The Navy and Signal Corps acquired a huge volume of wooden propellers, only to have them become quickly obsolete with the advent of better engine technology. The props were then sold as surplus for a few dollars each.

[guam2250]

Thanks again!