[modeleng] Re: Thoughts on future projects....
- From: "Clifton" <clif.gwr@xxxxxxxxxxxx>
- To: <modeleng@xxxxxxxxxxxxx>
- Date: Sat, 17 Mar 2012 12:54:04 -0000
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
>
> On 15/03/2012 11:36, Chris Crosskey wrote:
>> Hi folks,
>> I need some advice...
>>
>> In the next month or so the move of my old workshop at my parents house
>> to my new very much larger workshop at my house will be complete (it's
>> only taken two years to sort it out :))...
>>
>> Given how I work I rather suspect I will want to have three projects on
>> the go once I've settled in..
>>
>> 1: The restoration of my horizontal mill...
>> 2: Construction of an Orrery
>> 3: It's about time I built something powered by steam...
>>
>> The mill is an old Herbert Simplimill, built like a tank, not all that
>> big but weighs nearly a ton, I've got the vertical head for it and have
>> tracked down some tooling... apart form just putting it back together and
>> getting it running right I need to make some changegears for it as that's
>> what it uses for setting speeds (and feeds) and I'm considering long-term
>> putting Norton-style gearboxes on it for speed and feed selection.... The
>> actual things I might do rather sooner than long-term is make a
>> quill-based vertical head for it so that I can use it as a drilling
>> machine, and I have a slotting head (from something else) that I'd like
>> to get working on it too. Would welcome advice from people who have
>> recommissioned mills or similar machines from a big pile of parts....
>>
>> The orrery is just something I want for my lounge and if it takes me 15
>> years to get through that much watchmaking then so be it, I'll take it in
>> easy stages, start off with an earth and moon, add a Sun, then the inner
>> planets, then Mars, then build separate sets for the giants then get the
>> whole lot working as one.... Don't need advice for that..
>>
>> The third bit is the one where it gets more complicated.... I've got two
>> things in mind.... A steam powered bicycle based on the Hope layout
>> probably built onto a butchers bike or similar, or a steam paddle launch.
>> The launch would need to have a disassemblable hull ...I know how to do
>> the disassemblable bit but I've never built a boat hull before and would
>> need a design that I could adapt... Hopefully by making it disassemblable
>> I could build an 18-foot or so paddle launch which would fit onto a
>> smallish trailer. I've seen a launch that size (paddle too) running off
>> the boiler and engine of a 7 ½" Shay (literarally mounted in the hull
>> minus its wheels with the shaft taken to the paddle drive.... I'd prefer
>> to do it with a vertical boiler of some description and a freelance two
>> or three cylinder engine.... Any advice welcome there too... I'd want the
>> boiler to get within the model boiler regs for ease of certification
>> (it's not that the regs are less tight, it's just it's
> ea
>> sier to find a tester and cheaper to get done...)... are there any
>> designs for vertical or marine boilers near the model limit? What sort of
>> pressure would be sane? 80psi? 150psi? What does a 7 ½" Shay have in
>> terms of bar-litres and engine bore/stroke?
>>
>> chrisc
>>
>
>
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