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[ta0]

Jim already has a video he will be posting later  . Cyril's still works well, although the height is not what it is implied on the box drawing (thanks Cyril and Jim):



The drawing of La Nature for reference:



I wish old British patents were available online as the US Patents are. I wonder how difficult they are to get. This one has the low number 3,597.

[jim in paris]

here is the vid

filmed by Cyril late last night , just for our entertainment!!

it does makes a shower 

 


jim

[Lourens]

Today I made also a video of the fountain top spinning in water. My problem was that the axe is not quite straight so that influences the spinning and perhaps also the height of the fountain. The water is sprayes aside quite far (Ø 70 cm) and the height was humble, 35 cm). An other difficulty is make the fountain visible at the video. Clear water is clear water and my background was white! So, the next attempt will be with a dark background or using coloured water. To be continued!
... Or not to be! Cyril posted his video at the same time I wrote this comment. His fountain top does exactly the same as mine but it is better visible because of the black background.

[lincolnrick]

Thank you both for bringing us this marvel of engineering!

[Russpin]

here is the vid

filmed by Cyril late last night , just for our entertainment!!

it does makes a shower 

jim

Great video! Thanks for posting! I wonder if spinning by a string could make the water go even higher.

[ta0]

NICE! It is so wonderful to see this legend of top collecting in action! 

Lourens: I would still like to see the video that you filmed, even if the water is not very visible.
Did you spin it on a plate of that period by any chance? 
I bet this is the first time in 100 years that two of these tops are played the same day.

I have some questions:
Is the opening completely submerged? Does any air enter through there?
Does it blow substantial air if spun dry?

The article in La Nature specifically mentions that the rubber foot fixes itself to the plate and stops the top from wandering and wetting all over. I guess any rubber on the stand has dried up long ago.

I wonder if spinning by a string could make the water go even higher.

It was spun using a string.

[Jack]

this thread is bringing me much joy 
that thing is an engineering marvel eh!!!

[Diz]

Incredible! Thanks for showing that in action!

[Jeremy McCreary]

What a fine puzzle! Many thanks to ta0, Jim, Cyril, and Lourens for the data points to ponder. What we could really use now are some close-up photos of (a)  the "water intake" at the bottom of the "rotor" (spinning assembly) just above label "B", and (b) the rotor "side hole" described in ta0's opening post.

For Cyril: Can you tell where that side hole leads? Can you tell when air enters it? Do you ever see water coming out of it? What happens when you tape over the side hole? Any and all answers greatly appreciated.

One interpretation of drawings and video: Consider 4 main "stages" of fountain top operation:  (i) "Spin-up". (ii) "Air fountain" (string release to moment of water intake immersion). (iii) "Priming" (of water flow). (iv) "Water fountain" (little if any air flow).

The self-priming air fountain forms spontaneously during spin-up under centrifugal force and peaks in flow at string release. Air leaving the top at the fountain outlet just above label "D" during the air fountain stage enters primarily via the water intake. Air entering the water intake begins to entrain water as the intake submerges. This initial water charge kicks off the transitional priming stage, which ends with establishment of hydraulic continuity between the external water reservoir and the water fountain outlet. The water fountain stage is then fully developed.

What goes on inside the rotor reservoir "R" during priming phase is probably pretty complicated -- especially if air enters the side hole during this time. If air enters the side hole during water fountain stage, it may serve to aerate the water entering the fountain inlet "C". Reducing the average density of the discharged water in this way would effectively reduce the hydraulic head that must be overcome during water fountain stage.

[ta0]

I am sorry for the confusion. My initial description was wrong. There is no external side hole. Only a hole at the end of the pipe, but still internal to the reservoir.

I think your priming theory followed by a purely hydraulic stage is probably correct.

[Dick Stohr]

What if it is very simple? When water enters the bottom hole it spins with the inside of the chamber and centrifugal force makes it climb the wall. When enough water pools at the largest diameter it is forced into the tube that goes to the outlet with enough force to make the spray.

[Jeremy McCreary]

What if it is very simple? When water enters the bottom hole it spins with the inside of the chamber and centrifugal force makes it climb the wall. When enough water pools at the largest diameter it is forced into the tube that goes to the outlet with enough force to make the spray.

Absolutely right, Dick: It is that simple during the final stage of steady water fountain flow. But things aren't so simple during the water priming stage that comes before. The strong air-water interactions characterizing this phase begin when the water inlet first goes under and end when the water fountain achieves steady flow.

Just because it's fun to think about, I still have a few questions: (i) Air and water intake design, (ii) how air flow established prior to immersion actually primes the pump, and (iii) the air-water mix at the fountain outlet during water fountain steady flow. Guessing that the answer to (iii) is close to 0%.

[Dick Stohr]

I think air has nothing to do with it. I have an enclosed top with fluid about 1/3 full. when the ripcord is pulled all of the fluid goes to the largest diameter and stays as long as the top spins. So there is no "priming". Any fluid on the inside of the chamber is forced to spin with the  moving surface by friction and it rides up the sloping side by centrifugal force.

[Jeremy McCreary]

I think air has nothing to do with it. I have an enclosed top with fluid about 1/3 full. when the ripcord is pulled all of the fluid goes to the largest diameter and stays as long as the top spins. So there is no "priming". Any fluid on the inside of the chamber is forced to spin with the  moving surface by friction and it rides up the sloping side by centrifugal force.

I have no doubt that that's what happens to water already in the reservoir. However, I'd still like to see the intakes.

[Dick Stohr]

I admit that I do not know but I would bet that it is just a hole that must be completely under water to start and to continue supplying the water up to the spray section.

Jim can you shed some light on this? How deep was the water for the tests/videos you guys did? And did the bottom hole remain completely  under water while the spray was active and did the spray stop when the water was lower that the hole?