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Paddle Power

Posted by
CElliottUK (Reading, United Kingdom) on 13 July 2012 in Business & Industry.

This is the original water-wheel at Mapledurham.
Now, dear Am3'ers, you know I like water power as an alternative power source, so, obviously I wanted to know how much power it produced at its height of refinement and maintenance. The staff at Mapledurham didn't know, and just kept talking about how many bags of flour it could mill.
So, based on some "Back of fag packet" hydrodynamic calculations I reckon it could produce around 10-15Kw. This number becomes important tomorrow....

This ended up being a desperately irritating shot to take-either the sky and the wall were completely bleached out, or the right hand part of the wheel was completely black I kept looking at the wheel, take a shot, "Chimp" on the back of the camera, not see on the back what I saw in the flesh, up the exposure, down the exposure, not be happy. So this ended up being a 3 shot handheld sequence that I manually masked together(i.e. no automated HDR, but instead chose which bits of over, under and normal exposure made it through to the final image)

Canon EOS-1D Mark IV 1/250 second F/11.0 ISO 1600 10 mm

David from Avranches, France

Well sir you manual masking together worked a treat. Great shot Chris.

13 Jul 2012 5:06am

Christine from Ellemford, United Kingdom

You succeeded, great tones but I want to tilt it slightly to the right

13 Jul 2012 5:58am

Nicou from Sion, Switzerland

Quel cadrage sur cette roue au aube sueprbe cpmpo ce cieux bois quelle iamge.

13 Jul 2012 6:01am

Nazzareno from Rome, Italy

Wonderful composition and tones. I love it.

13 Jul 2012 6:12am

ursulakatariina from Leixlip, Ireland

Great work with the masking. Great tones and details.

13 Jul 2012 6:39am

Nigel from Avening, United Kingdom

All that was worth it - well done

13 Jul 2012 6:53am

J.R. from Urasoe City, Japan

I agree worth the effort.

13 Jul 2012 6:58am

jpla from St Barthélémy d, France

J'aime ces couleurs ! Joli cadrage ! Je te souhaite une agréable journée

13 Jul 2012 7:00am

l'Angevine from France

j'apprécie cette verdure que ce soir sur cette roue et que ce soit sur ce saule pleureur où chacun pleure à sa façon

13 Jul 2012 7:18am

Tede from Aubenas 07, France

Splendide cette roue de moulin, elles se font de plus en plus rare, très belle image. Bonne journée.

13 Jul 2012 7:46am

anne fleurent from Bois-le-Roi, France

très beau témoignage ! splendide effet !

13 Jul 2012 7:58am

Curly from South Shields, United Kingdom

You did a good job with the masking, I've known those very same frustrations!
At least now the front end of your picture looks pretty perfect.

13 Jul 2012 8:23am

Doug from Burnham-on-Sea, United Kingdom

Superb bit of bespoke processing Chris, a nice shot

13 Jul 2012 9:04am

Tamara from Aarschot, Belgium

Perfect post-processing Chris... This is excellent work ! Have a lovely day :)

13 Jul 2012 9:49am

Stephen from Canberra, Australia

Great effort on a very tricky exposure. The result is wonderful clarity that takes us right into the scene.

13 Jul 2012 9:51am

Jason Politte from Conway, AR, United States

That's the way to do it, Chris. Superb shooting and editing - it looks great!

13 Jul 2012 10:57am

SalSa from Tehran, Iran

You have chosen a very excellent and interesting angle. Images are very fantastic.

13 Jul 2012 12:11pm

CATCHLIGHT from Reading, United Kingdom

very nice angle of the dangle

13 Jul 2012 1:36pm

Mhelene from Paris, France

Superb framing ,texture and colors !! Very beautiful . And interesting !!

13 Jul 2012 1:37pm

Heinz from Hamm, Germany

Sehr schön dieses alte Mühlrad.

13 Jul 2012 2:14pm

Melocoton from Salamanca, Spain

wonderful shot, bravo

13 Jul 2012 3:25pm

Becky from los angeles, United States

I'll use my WOW word here.... the mass, the moss, the angle, love this shot.

13 Jul 2012 4:43pm

Ruthiebear from Titusville, NJ, United States

The moss on the paddle makes a good tie in to the background. I like the shapes of this paddle and wheel.

13 Jul 2012 5:19pm

Sam from Chennai, India

Great shot and interesting information. :)

13 Jul 2012 5:21pm

Judy aka L@dybug from Brooksville, FL, United States

A super 'cloned together' image ... giving us what you wanted ... okay, 15Kw ... I'll remember that!

13 Jul 2012 5:56pm

The Mouse from Glasgow, United Kingdom

Last time i saw this was the show, looking forward to your power info as i now have a huge dislike for the wind turbines

13 Jul 2012 6:55pm

kiwisa from North Shore, New Zealand

Certainly a long process to get all the detail in this shot, but so worth it.

13 Jul 2012 8:47pm

Ted from South Wales, United Kingdom

top the perspective and no hint at the difficulty of shot.

13 Jul 2012 10:03pm

Michael Fresh from Chester, United Kingdom

A nice composed shot of that lovely old wheel.

How did you calculate the estimated power output... I'm interested to know if you took into account the rate of flow of water, as well as the surface area of the paddles these would have an effect on the torque of the shaft.

13 Jul 2012 11:24pm

@Michael Fresh: This really is rough and ready. I was told the speed of the millstones, by roughly counting the gear cogs on the drive train I could work out the rotational speed of the paddle wheel. The wheel had two power inputs. There was a small drop in height from the upstream to the downstream water, and there was the flow of the water. By approximating the volume of water that flowed through the wheel(By knowing how fast the wheel went round, and therefore being able to calculate the volume and mass of water flowing through the wheel-because I estimated the width and depth of the paddles, I could work out the kinetic energy. By knowing the height difference, I could work out the potential energy difference. The two added together came to around 20Kw, however, I reckoned that taking into account friction, and other losses in the gearing system, 25% of the energy was wasted in heat and drag. As a cross check, I measured the speed of the river by throwing in some grass, and seeing how long it took to travel 10 metres. By knowing the speed of the water, and therefore the mass of the water that would be "swept" through the wheel in an unconstrained way, I ended up with around 30Kw, so I was happy I was roughly in the right ball park.

Michael Fresh from Chester, United Kingdom

Well done Chris, I was going to mention the reduction of power through resistance from the drive shaft and gears; but most important is a constant volume and velocity of water. I think these waterwheels are a brilliant invention. Did they have a generator hooked up ?

14 Jul 2012 12:35pm

@Michael Fresh: No, this is a non-working tourist attraction. But they have augmented it by the much more efficient device I show tomorrow

Ronnie 2¢ from Atlantic Shores, United Kingdom

Fascinating image and story-debate here - plus the exchange of info ! When I get caught in rain shortly, I shall feel myself re-charged as well as bedraggled !

16 Jul 2012 6:44am

Canon EOS-1D Mark IV
1/250 second
ISO 1600
10 mm