[modeleng] Re: Thoughts on future projects....
- From: Terry Lane <tel.47@xxxxxxxxxxx>
- To: modeleng@xxxxxxxxxxxxx
- Date: Sun, 18 Mar 2012 07:01:25 +1100
Ah.. I don't know about that - feathering paddles look a lot more
complicated than they actually are and would add a great deal of
interest to the project. The sponsons add very little to the overall
width and I have seen successful examples here in both model and small
'real' boats.
On 18/03/2012 4:47 AM, stepney wrote:
> Fitting the feathering to a small boat, with the complexity it entails,
> would be a major task.
> Plus the added width might make life difficult, not least for
> transporting the boat on land.
> Hence I assumed (perhaps wrongly) that it wouldnt have feathering paddle
> wheels.
>
> I wouldnt be in favour of electrical powered boiler. If it is going to
> be used, may as well fit an electic motor!
> Alan
>
> On 17/03/2012 12:54, Clifton wrote:
>
>> Hi All,
>>
>> For the best efficiency of paddles they need to feather. This means that
>> each paddle enters the water vertically, travels backwards through the water
>> then exits again vertically. This avoids the loss of efficiency by the
>> paddles first slapping the water then trying to lift a load of water
>>
>> To achieve this it means that each paddle has to pivot individually with a
>> linkage to a fixed offset point. Rather like a loco eccentric.
>> The biggest snag is that you need a set of sponsons outboard of the paddles
>> to carry the fixed eccentric point.
>>
>> Just recently I think in EIM there was a article on a model boat with a
>> electronically controlled Flash steam boiler. I see no reason why it could
>> not be scaled up.
>>
>> Regards
>>
>> Clif
>> ----- Original Message -----
>> From: "stepney"<alan@xxxxxxxxxxxxxxxx>
>> To:<modeleng@xxxxxxxxxxxxx>
>> Sent: Saturday, March 17, 2012 11:11 AM
>> Subject: [modeleng] Re: Thoughts on future projects....
>>
>>
>>
>>> Coming back to the steam options that Chris mentioned,
>>>
>>> I know someone who has done a lot of research on steam bikes. An
>>> ex-university lecturer, he has written an interesting paper on them plus
>>> a comprehensive survey. There was one running at the St Agnes rally a
>>> few years ago.
>>>
>>> Generally, they werent too successful as motorbikes, but could be good
>>> fun.
>>>
>>>
>>> As for steam boats, there was an interesting flash steam boiler at... I
>>> think it was Donnington, a few years ago. I have photos and details
>>> somewhere.
>>> It made a compact unit that provided lots of steam.
>>> Plus, of course, no actual pressure vessel to test.
>>> That would be my choice for such a vessel. The other option is a
>>> vertical boiler, which is common and for which there are numerous
>>> designs available.
>>>
>>> For the engine, and without doing any calculations, I would guess that 3
>>> or 4hp, would suffice.
>>> (Paddles being less efficient than a screw, and to raise the efficiency
>>> of paddles means quite complex paddle design, so I assume they would be
>>> fairly basic=less efficient.)
>>> There are lots of engines that would provide that power. Some of the
>>> Leak designs would do, but for a paddle steamer, I would go with an
>>> inverted V, much like the model that Tel built last year (or was it the
>>> year before?).
>>> An enlarged version of that would give a low CofG, and take up little
>>> space.
>>>
>>> Alan
>>>
>>>
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