Paddleducks

General => Paddleducks Website/Forum => Topic started by: R.Groff on February 28, 2016, 01:52:18 AM

Title: Paddle wheels
Post by: R.Groff on February 28, 2016, 01:52:18 AM
Is there a depth the paddle wheel should be into the water are there set guide lines as to how far past the water line to go looking for any help .
 Rick
Title: Re: Paddle wheels
Post by: DamienG on March 27, 2017, 07:48:06 PM
I'd like an answer to this question as well can any member help please?
Title: Re: Paddle wheels
Post by: derekwarner_decoy on March 27, 2017, 08:41:58 PM
Hullo Damien & Mr Croft........one of the best answers to this never ending quest is to ask the question of Mr Google.....

"optimum depth of paddle wheel blade in water"

This will then confirm 1286 individual WEB threads on the subject  :yeahbaby

Good luck & goodnight  :beer..... Derek

Title: Re: Paddle wheels
Post by: DamienG on March 27, 2017, 11:13:44 PM
In other words no one here knows?

I find this amazing from a group of Paddle enthusiasts.
And after severals of scanning google am still none the wiser.

Damien.
Title: Re: Paddle wheels
Post by: derekwarner_decoy on March 28, 2017, 01:06:29 AM
Goodness Damien....... :a102 ...I am not sure of the Google you are using, however when I ask the question

"optimum depth of paddle wheel blade in water"

I get 484,000 [yes four hundred and eighty four thousand lines or responses to my question]

I have not attempted to read them this evening........ :shhh

.......so I don't quite understand where you are coming from?....... :sorry

Derek
Title: Re: Paddle wheels
Post by: chewbacca on March 28, 2017, 01:15:08 AM
Hello
I put my axis in the good level as on the plan and wheels are at the right place normally,  I did not ask myself more questions, it dabbles! :vacation

j-claude

Title: Re: Paddle wheels
Post by: petermun on March 28, 2017, 03:51:37 AM
I have no idea of the correct depth, but I have just refurbished a 40 inch model of USS Powhatan and fitted the paddles so that the upper edge of the blade lowest in the water is level with the waterline.   Works for me.   Pete
Title: Re: Paddle wheels
Post by: DamienG on March 28, 2017, 10:47:15 PM
Closest I got was a pic' with the top of the lowest blade just below the surface but no explanation why.
Title: Re: Paddle wheels
Post by: Hankwilliams on March 29, 2017, 03:15:50 AM
Dear Friends,

this is a very difficult theme... Different assumptions are important: General the speed of the paddle wheel blade in the water and the angle of the blade when it comes into water and got out water. In practice 3 blades should be in water together by feathering wheels. By wheels with rigid blades should be more blades together - however of the bigger diameter. Should be 6 like in picture 2, when the diameter is double. The grade of efficience depends more on the diameter of the wheel and not first whether the wheel has feathering blades or not. One fundamental thing: A wheel with feathering blades has approximately the same grade of effect like a wheel with rigid blades of the double diameter.

To the pictures: First picture shows the European tradition with small wheels with feathering blades. Second the relation of efficiency between small wheel feathering and big wheel with rigid blades - in this example it would be approximate equal. Picture 3 shows a cross section of the very fast Hudson paddler "Mary Powell", it`s known, that this boat sometimes reached more than 20 miles/h (37 km/h) - American tradition like picture 4.

From my experience, the depht of the blades like you see in the pictures, is best for propulsion.

You know, English is not my native language, nevertheless I hope, it`s clear what I wanted to say.

Thomas
Title: Re: Paddle wheels
Post by: DamienG on March 29, 2017, 05:35:16 PM
Thanks Thomas greatly appreciated a good explanation explanation that answers mine and Rick's question.  :clap :clap :clap
Title: Re: Paddle wheels
Post by: Bierjunge on March 31, 2017, 08:38:18 PM
Thomas,

That's an excellent find! may I ask which publication this is from?

For those very deeply interested in the mathematics of paddlewheels, there is further reading at http://www.steamgoon.com/books.html (http://www.steamgoon.com/books.html).

Examples:

(http://www.steamgoon.com/images/Thurston/Thurston182.jpg)
(http://www.steamgoon.com/images/Thurston/Thurston185.jpg)

Moritz
Title: Re: Paddle wheels
Post by: Hankwilliams on April 01, 2017, 05:18:28 AM
Moritz,

it`an article in the journal "das Logbuch" 4/2000.  The article describes the differences between American and European paddlesteamer; specially by the example of the Danube steamer "Johann Baptist". As far I know this and the similar "Europa" were the sole steamers with American walking beam engine and oversized paddlewheels in Europa.
A good model of the "Johann Baptist" I found many years ago in Budapest Transport Muzeum.

Thomas
Title: Re: Paddle wheels
Post by: Talisman on April 24, 2017, 08:06:41 AM
Hi all,

I think if you are using builders drawings then the answer is on the plan.
To define it in a simple way that fits all boats will lead to ...confusion, probably.

It's a bit like trying to answer the Rpm of a paddle wheel in a scale model question. Having said that we have settled on 300rpm for our wheels after much testing and knowing you don't have to run at 300rpm all the time.

The other question of feathering or fixed .. my thoughts are - if fixed were better they would have been fitted to the real thing ...

Of course in real life, cost, time and willingness to get it right is the  modeler's decision ..

Just thoughts.
Regards,
Kim