I went to the pond yesterday and tried to float my boat but it was quite cold and windy with half the surface covered with ice so I packed it up and went to socialise with an old friend ... ate borscht and rum babas.🌧️

My Glasgow makes gentle headway with the paddles rotating so slowly that I can see the individual paddles enter and leave the water. I estimate that to be less than 60 rpm, as that is one rotation every second - I doubt that I could see the paddles at that speed.
I had the opportunity to take a trip on the coal-fired paddle steamer Kingswear Castle along the river Dart a few years ago, and the paddles rotated quite slowly, but they did move quite a lot of water in the process. I expect the views of the river and mouth of the Dart were very pleasant, but I only looked at the paddles and the gleaming steam engine!

Hello RPLedm greetings to all naval modelers.

Although I have never built a scale model of a RC paddle steamer, I have always followed with great attention those who have attempted this construction.
They are not many, the good Mike, Tomarrack, River Rat, Oxford-Dave and a few others.

Regarding the rotation speed I have already intervened on the matter, precisely in Mike Stoney's "Build Blog", entitled "Old Stern wheel steamer", in which Mike updates us on the developments of a beautiful and very interesting work.

I report verbatim what I already wrote nine months ago:
"Having no experience on wheel-propelled steamers, I wondered how I would prepare the electrical part from the beginning.
First I would have asked myself what the number of revolutions of the paddle wheels is, to have optimal navigation.
Not having any reference I tried to imagine it in my mind.
Maybe a starting point is one revolution per second, that is, 60 revolutions per minute., I said to myself.
I imagined a wheel of that size and thought that if it completed one revolution in one second, it would be quite plausible.
I would then have done some practical tests and if it had been too fast or too slow I would have acted accordingly by changing the speed reducer.
Then I read the indications of River Rat which has 50 rpm and now I read an even lower value: 42 rpm."

In short, based on imagination but also on other feedback, I thought that 180 rpm was too much.
Let's say that, hypothetically (except to do appropriate tests) you can take the value of 60 or 50 rpm as a reference.
However, you have to consider the entire travel of the accelerator lever on the radio control from a minimum to a maximum value.
Therefore, depending on your tastes and needs, I would stay between a value between 60 and 120 rpm.
With 120 rpm, probably (but these are all my hypotheses) I will have a realistic speed only with the throttle lever at minimum.
I prefer to do realistic navigation at minimum throttle and have the possibility of running away (even if unrealistically if necessary), so I would choose 120 rpm.
Those who want a realistic speed even at full throttle, then should not exceed the value of 60 - 80 rpm.

I go to the pond for a pleasant relaxing time, with a simple picnic and my with best friend. She is a "crafty" and spiritual person who appreciates the time and effort which I put into my work and who mixes well with the other sailors. A slowly moving ship adds to the ambiance. An ambling walking speed sounds just about right, say about 60 rpm.

My Graupner Glasgow was bought already built and sailed, with an MFA 540 motor with integral 2.5:1 reduction gear, driving the paddles through a further 3:1 reduction. On a 7.2 NiMH pack I couldn't open the throttle more than about 20% or the paddles simply created froth and noise, but very little propulsion.
I have now re-motored it with an MFA 540 which has 11:1 reduction drive, still with the 3:1 final drive to the paddles, and it is now a joy to sail, though full throttle is a little unrealistic.
I calculated from the motor data that the paddles are doing about 180 rpm max, though I rarely use full power on the water. The Glasgow uses about 1.5 amps of battery capacity in a two hour session on the water.

It is possible that I did not directly address the content of your post.
Forget Froudé and Reynolds. I'm afraid there's a big problem with the theory in such models. You can theoretically calculate the length, speed, displacement from the scale of the model, but the speed of rotation of the wheels is too dependent on the design and efficiency, which can't be determined in advance.

More about paddle wheels rpm .. I also recommend you take a look at the website, www.paddleducks.co.uk ,
, which is mainly intended for paddle boat lovers.

Tom

As for me and my models with paddle wheels, I think it is necessary to test the optimal speed setting, which depends on the size of the model and the design of the paddle wheels.
The lower limit is calculated from zero rpm, the optimal working speed of the wheels also depends on the type of ship - calculate around 80 - 150 rpm. In no case should the steamer sail at the speed of a racing boat - but I saw that on the video too.

For example, my model of the Lulonga steamer has, in my opinion, an optimal speed, as if you were walking at a slow pace.
It is built in 1:32 scale.

"Time does not scale from the actual thing to the model"

This is very interesting.
What do you mean exactly?

Hi RPLedm, were you explaining the concept and the resonance circuit when capacitive and inductive reactances are equivalent?
How nice to know that the laws of physics are valid all over the world and the discovery or invention of an Italian, an Englishman, a German, a Frenchman, an American, a Serbian, etc. etc., over the centuries, benefit everyone and make the whole world progress.

Apparently this is a bit of a mystery. For those in the know and inducted into the mysteries and practices of fluid mechanics and who have been introduced to the gods Froude and Reynolds there is but one overriding theorem: Time does not scale from the actual thing to the model. A discussion on the subject could get a titch complicated. Are we up for it? My former colleagues and I used to joke about our teaching: if you put one equation on the board you lose half the class. If you put up another you lose the other half ... 🤓
Edit: Forgive me but someone asked about time not scaling.
Consider a building 100 m tall. The time for a stone to fall 100 m (no air resistance) is 4.5 seconds. A 1/48 scale model would be 2.1m tall and a stone would take 0.65 sec to fall that height. The 0.65 sec is not 1/48th of 4.5 sec. It is a ratio of 1/7. Time has not scaled.