Very large unknown wooden prop

[JMPM]

Hello enthousiasts!

I have an old, very large propellor, which used to hang in an old cinema-bar. It is 335 centimeter (10.9 feet/132 inch) in length, 21 cm (8.2 inch) width (hub) and 4 cm (1.6 inch) thick (hub). The hub has 4 holes surrounding a larger, central hole. The back of the hub shows a rectangular imprint. The propellor is made from one piece of wood (pine?) and does look old and used. The pitch of the blades is very low, they resemble aircraft-wings. I suppose it is to large and wrongly pitched for an aircraft propellor. The edges of the blades are nearly rectangular and rather thin. It is designed to turn counter clockwise. The following links show pictures I made with my phone (sorry...). I hope anyone can give me any information about this huge (and very decorative!) object.

http://i397.photobucket.com/albums/p...r/SP_A0849.jpg
http://i397.photobucket.com/albums/p...r/SP_A0848.jpg
http://i397.photobucket.com/albums/p...r/SP_A0847.jpg

Thanks in advance.

Greetings from Holland,

JMPM.

P.S.: What a wonderfull site and Forum! WOW!

[Bob Gardner]

Thank you for your kind words and welcome to our forum. I hope we have lots more posts from you.

I agree that this is not an aircraft prop. It might be from a wind driven pump of the type that was common from the 1930's to the 1950's.

Bob

[JMPM]

Hello Bob Gardner,

Thanks for your welcoming words. I do really like this site (esp. Forum) and your site (aeroclocks) as well. As a student in Military History with a passion for (military) aviation, I sure hope I can contribute something to this Forum. I respect your work (articles and books) and I am delighted to share in your knowledge and enthousiasm.

Thanks for the comment on my giant propeller. I doubt that it is a wind generator prop, for the fact that the blades are not optimal for generating kinetic energy. I'm no fysician, but I think that the blades (low pitch with a thick, slightly pitched (under camber) airfoil are not ideal for 'catching' windenergy. An aircraft doesn't tend to move forward if wind blows straight on top of it's wings, does it? I suggest that it is designed to move the air itself, by creating lift with minimal drag. I have no clue of what it was meant to propel or supply with wind/turbulence... The hub (4 boltholes) and the thin and long blades with the typical pitch/airfoil exclude high RPM's or airspeeds.

So, to summarize: To my opinion there are three options:
1.) I'm wrong and it is a (efficient) generator/pump propellor.
2.) It is a propelling or blowing device for an unknown object.
3.) None of the above: It is produced as a decorative object.

The third option is weakend by the fact that the blades show signs of usage. Especially the hub suggests authenticity, because the holes show markings of a grooved driveshaft and the boltholes are used. There are remains of oil/tar and the imprints (front and rear) show that it was in some way mounted to an engine or other device...

Any suggestions on this exciting exploration? Please prove me right or wrong! In the meantime I'm stuck with a huge, unknown piece of historical wood in my livingroom: Fantastic!

Thanks in advance and good luck with helping me and others!

[JMPM]

Hello Bob Gardner,

Thanks for your welcoming words. I do really like this site (esp. Forum) and your site (aeroclocks) as well. As a student in Military History with a passion for (military) aviation, I sure hope I can contribute something to this Forum. I respect your work (articles and books) and I am delighted to share in your knowledge and enthousiasm.

Thanks for the comment on my giant propeller. I doubt that it is a wind generator prop, for the fact that the blades are not optimal for generating kinetic energy. I'm no fysician, but I think that the blades (low pitch with a thick, slightly pitched (under camber) airfoil are not ideal for 'catching' windenergy. An aircraft doesn't tend to move forward if wind blows straight on top of it's wings, does it? I can't see a way in which this propellor can profit from a breeze from any direction.

I suggest that it is designed to move the air itself, by creating lift with minimal drag. I have no clue of what it was meant to propel or supply with wind/turbulence... The hub (4 boltholes) and the thin and long blades with the typical pitch/airfoil exclude high RPM's or airspeeds.

So, to summarize: To my opinion there are three options:
1.) I'm wrong and it is a (efficient) generator/pump propellor.
2.) It is a propelling or blowing device for an unknown object.
3.) None of the above: It is produced as a decorative object.

The third option is weakend by the fact that the blades show signs of usage. Especially the hub suggests authenticity, because the holes show markings of a grooved driveshaft and the boltholes are used. There are remains of oil/tar and the imprints (front and rear) show that it was in some way mounted to an engine or other device...

Any suggestions on this exciting exploration? Please prove me right or wrong! In the meantime I'm stuck with a huge, unknown piece of historical wood in my livingroom: Fantastic!

Thanks in advance and good luck with helping me and others!

Regards from Holland,

JMPM

[JMPM]

Oopss...

Something went wrong here... Three times.... Moderator?

Thanks

[Bob Gardner]

I thought you had a stutter.

Bob

[JMPM]

LoL! I can make a fortune stuttering like that!

[Dave]

I deleted one of them, but left another duplicate just for effect.

[Bob Gardner]

Back to your long thin prop. The high aspect ratio blades are for efficiency and are similar in concept to those on the enormous wind turbines which are now so common in the Netherlands. Your prop is designed to operate at slow speed.

The four bolt holes are insufficient to transmit much power, certainly not enough to get an aircraft off the ground.

It's from a wind driven pump, probably one which maintained water levels in polders.

Bob

[JMPM]

Hello Bob. Thanks for your reply.

A wind-driven-waterpump-propeller it is, then!

I hope to take it outside soon, mount it on an axle and wait for wind.
This should proof my doubts about the inefficient airfoils of the blades wrong. A report on this will follow.

Jochem

[Dave]

I've seen similar looking propellers in vineyards in California, but I'm not sure whether they are passively wind driven to run some kind of pump, etc. or whether they are used actively to move air across the vines.

I was told somewhere that the Jacuzzi Brothers in California originally began their business making some kind of "foggers" for moving air over crops, then quickly switched to aircraft propellers when that need became evident. Jacuzzi was a major propeller manufacturer in the teens.

[JMPM]

Thanks for the suggestion, Dave. Do you have any pictures and/or data on these 'foggers' or airflowgenerators? Are there any pictures of ancient vineyard turbines? Thanks.

[Dave]

Here's a picture of one. I took one myself a few years ago when I was in Napa, but in got lost in a computer crash. Google "Vineyard wind machine" for some more information.

[MWP_Lamar]

Here's another with a wooden prop from a vineyard in Napa Valley, CA.



Lamar

[JMPM]

Thanks for the pictures and information, guys!

Although the blades of my prop are far less pitched than those showen in the picture, i can see no other possible use than it being an active windproducer or a waterpump propeller. I still believe that the low pitch and thick airfoil look quite inefficient for both purposes, though...

As said: I will test the prop as a windmaker and windreceiver.

Jochem JMPM