Early Paragon or knockoff?

[cubflyer1946]

I recently acquired this propeller from an estate and was wondering if I could get some thoughts on its originality. A 1918 Curtiss OX-5 engine hub fits it perfectly. It has the correct slength and shape for a Curtiss Jenny airplane. There are a few markings/numbers on the hub as you can see, but nothing else on the propeller. I was thinking it could be an early Paragon propeller, but it could also be a knockoff wallhanger. Any thoughts would be appreciated.

[Dbahnson]

It's almost certainly authentic, although it may we’ll have been refinished later, or it may have been a factory reject.

That is a very common design for Paragon, and there are a lot of them still in existence.

[cubflyer1946]

My I ask what leads you to believe its authentic? Do you think its an American Propeller Company Paragon? Any idea what the numbers are on the hub? Serial number?

Thanks,

Glenn

[Bob Gardner]

What an elegant shape !!

Bob Gardner

[Dbahnson]

My I ask what leads you to believe its authentic? Do you think its an American Propeller Company Paragon? Any idea what the numbers are on the hub? Serial number?

Thanks,

Glenn

It's a characteristic and common shape that was made under the Paragon trade name, and I haven't seen an exact duplicate made by any other manufacturer, although there are a lot of scimitar shaped props that "sort of" resemble that design. I think the numbers are most likely early production numbers, which might support the reject hypothesis, but I've seen these props come out with all sorts of different patterns of stampings on them, some as simple as a number surrounded by two asterisks, and nothing else.

It would also be time consuming to make a reproduction, and one of the reasons that the scimitar shape was eventually abandoned was that it wasted a good deal more lumber than straight props, which seemed to work just as well.

I've owned four or five of these over the years and have kept the best one because of its original condition and evidence of actual use rather than surplus or reject. Some had metal sheathing and others did not. They were offered as surplus for $2 in the early twenties, but the metal sheathing raised the price to $3.

[Bob Gardner]

I recall that Vickers-Levasseur produced a similar looking scimitar prop circa 1912. These props are exceptionally rare in Europe. I believe I have only seen two in the last thirty years. The shape is so idiosyncratic that it seems unlikely that it could be invented twice, once in Europe and once in the States. It seems unlikely that the seminal Lucien Chauviere in France designed it. His work was in laminated two-bladed wooden propellers of the conventional shape we see today, but they were the product of Lucien Chauviere's work and revolutionary at the beginning of the last century.

I wonder if there was a connection between Vickers or Levasseur in Europe and Paragon in the USA?

Bob

[Dbahnson]

The American Propeller Manufacturing Company in one of their catalogs touted the scimitar shape as creating a variable pitch effect by reducing the pitch at high RPMs then returning it to a higher pitch as RPMs were reduced in cruise. The effect was presumably created by twisting of the wood adjacent to the hub in response to spinning of the blades.

Whether that actually happened or not is unclear to me.

[pmdec]

Hi,

I think the Vickers-Levasseur turns the other way (the leading edge is concave!). I have added arrows on the joined ad from 1912.
From memory, Pierre Levasseur said that this prop had an "auto-regulated" rotation speed: when the rotation accelerated, the pith was becoming higher (from wood bending). Perhaps it was efficient with low powered engines but as soon as the engines became more powerfull Pierre Levasseur came to the well known thin and straight shape...
I think that with high power engine, which had their power growing with rotation speed, the only result was to make vibrations at the tip which destroyed the prop.

Regards,
PM

[Bob Gardner]

I am still wondering how Levasseur and Paragon managed to produce almost similar scimitar shaped props circa 1912-1913. I think a possible answer is that the Paragon company sent a representative to the 1913 Paris Exposition de l'Automobile which had an aeroplane section, where he saw one of Levasseur's scimitar props and read of its self-regulation aspect. French aviation companies were the most advanced at this time and (in modern parlance) world leaders.

With kind regards,

Bob

[Dbahnson]

That's quite plausible. The early Paragon's were manufactured in 1912, so the timeline fits.