New little paddler

[Eddy Matthews]

Thanks for sharing the plans Thomas - I just wish I'd kept the Marten Howes & Baylis steamplant I once owned, it would have been almost ideal for this!

For those that don't remember my posts on the steamplant (It was about 15 years ago now!) you can see the complete thing at http://www.paddleducks.co.uk/smf/index.php?topic=1445.15 About the 5th post on the page...

Regards
Eddy

[Hankwilliams]

Yes, Eddy, this Marten & Hoves and Baylis steamplant was a first class one. I remember when it was offered in the end of 1990tis. The little slide crank engine I own in my "Seekadett", made in 1993 - still functionable and in good condition.

Thomas

[Hankwilliams]

Today we made some further pictures of "Presto". A few photos I modified with filters to an antique impression.

Thomas

[derekwarner_decoy]

Very good Thomas.....from IMG_2420, Presto appears to have a good radius of steerage 

Glad that pair of Wellington boots we bought you fitted correctly 

Derek

[Hankwilliams]

Oh yes Derek - this time I didn`t forgot the boots - there was a 4 meter distance throught water to the little dry isle!

Thomas

[DamienG]

A lovely model Thomas well done. 

[Paddlemex]

Nice pictures Thomas.
She looks nice on the water and seems to move really well.

Is it the picture or is Presto missing an E on starboard?

Jurgen

[Hankwilliams]

Yes Jurgen, the boats name lost an "E", I watched at home - fortunately I had another one - the name could be completet again.

In the next days I will take some pictures of the Irrawaddy steamer "Mindon". The text of the book about steamboat models is finished since weeks, in the moment there is some work to coordinate the numerous pictures with the text. I hope, also this will be finished next week.

Thomas

[kno3]

Please tell me what gear ratio did you use in in the beginning and how did you change it?

[Hankwilliams]

As I wrote in the "Mindon" topic the load of the engine was the problem - high steam consumption with restricted range of sensitive regulation.  I think, the present gearing ratio with 2 : 1 ist ideal for the dimensions of paddlewheels (120 mm diameter) and piston stroke (15,2 mm).

[kno3]

Thanks but that doesn't answer my question.

[Hankwilliams]

Perhaps we should have a look to the stroke of the engine in relation to diameter of the wheels. At original direct driven paddlers the engine stroke is between 20 to 35% of wheel diameter. This rate can be rendered to the model. With the 15,2 mm stroke of the Graham the wheels diameter should be between 50 to 75 mm direct driving. From my experience: When the wheels diameter is essential bigger, the torque of the engine will not be sufficient and the engine will be overloaded - steam consumption will be high. In this case a gear reduction is the better way, what was made with "Presto" and "Mindon".

Thomas

[kno3]

Thanks for the answer but I think you misunderstood me :-)
I was simply asking what ratio you started with and how you modified it. NOT why you didn't use direct drive (which is an entirely different question).

Besides, stroke alone doesn't tell much about engine power and load. You also need to know the bore of the piston and then to calculate the volume of the cylinders, working pressure, all in relation to the paddlewheel diameter and to the surface area of the paddles being submerged at one time. Quite a complex calculation, if you think of it.