Hamilton DES.H.561.X.RH. Prop Ser. No. 14202

[richlaut]

What do the H, 561 and X stand for in this design certification? I understand the RH. Can the approximate date of manufacture be determined from the serial number?

We think this prop may have been used on a Waco 10 with a Curtiss OX-5 engine. Are we in the ballpark here?

Prop length is 102.5" with an 8-bolt hub and attached wooden spinner - see attached photos.

Would appreciate any comments - thanks!

[Dave]

How do you know that it's a Hamilton propeller? If it is, then it was made before 1929, when Hamilton Aero merged with Standard Steel and became Hamilton Standard. During WW1 Thomas Hamilton was the manager at Matthews Brothers, but his name appeared in the logo for that company during that time, and he later went on to create Hamilton Aero. Some of his propellers will have a patent number stamped on the metal sheathing.

If you measure the hub dimensions carefully, you can exclude a number of engine possibilities and determine a high probability for one. I would guess that if the hub dimensions match those for an OX5 and with a propeller of that length it's a very high probability that it was designed for that engine.

[richlaut]

Thanks for your quick response, Dave. We know it is a Hamilton prop because of the label on each blade. I'm also familiar with Tom Hamilton and his company's history. Apparently the Hamilton company archives have been lost over the years - at least I haven't located anyone who might know.

I'm hoping that someone could direct me to the source of the DES certifications. They were apparently used by more than one company. Were they developed by a government or industry group?

Richard

[Dave]

It certainly appears to me that each propeller manufacturer was allowed to use whatever design nomenclature they choose. I do see an "H" prefix for the huge list of Ham Standard aluminum props, but that same reference listing just doesn't include any of the Hamilton wooden propellers. I suspect that when this 1983 listing was published that the Hamilton props were just so obsolete that they were not included.

Unfortunately, much of this manufacturing data and blueprint information seems to have been lost over time. I've searched the National Archives, the Library of Congress, and the National Air and Space Museum library looking for them, with very little success.

[richlaut]

Thanks again, Dave. I suppose the only hope would be to find a relative of a deceased Hamilton design engineer who might have received some details via inherited papers or verbal communications. Not likely to happen!

[pmdec]

Hi,
Could you post pictures of the labels?

Also, IMHO, the prop near the kitchen is a very bad idea for its conservation: large variations of temperature and humidity (and larger, if possible, near the ceiling!) is the best way to destroy the wood assemblage... and even each lamination!

[richlaut]

Thanks for your comments, pmdec. I've forwarded your request for label photos to the American Legion post commander. I think the prop was refinished and sealed....labels may have been damaged.