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Re: Antidote to Cabin Fever?

Posted: Sun Mar 29, 2020 7:38 pm
by dampfspieler
Hello Pete,

a suitable boiler could be such one like my 131350 EICHENDAMPF-VFT.
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I have tested it with my HASBROUK10-inspirated single (~ 2 PS).

https://www.youtube.com/watch?v=O9kkZjXPH2Y

A suitable engine could be a 32 x 38 mm single, a 32 + 55 x 38 mm compound or a 32 x 38 TWIN similar to the twin of my steam lorry MARTIN (ex. MODELWORKS "Pride of Penrhyn").
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Regards
Dietrich

Re: Antidote to Cabin Fever?

Posted: Sun Mar 29, 2020 8:08 pm
by PeteThePen1
Hi Mike and Friends

Having read the description in the vendor's website, I see that they have used an electric outboard motor successfully. So, rather than build in a heavy propeller, shaft, tube, etc. why not have one's steam engine driving a small dynamo that can be wired to the outboard. Not being an electrical person I don't know if one would be better to link them directly or to have a battery in between. Anyway, that might allow lighter and more removable plant albeit rather less than the full steam experience that Fred achieved.

Of course that might be a completely daft idea...

Regards

Pete

Re: Antidote to Cabin Fever?

Posted: Sun Mar 29, 2020 8:21 pm
by PeteThePen1
Hi Dietrich & Friends

Thanks for the post & photos, Dietrich. Your boiler the 131350 EICHENDAMPF-VFT. looks just the part. How heavy would it be in operating condition?

Yes I recall your Hasbbrouk engine and the superb modifications that you made to it. I'm not sure that all of us are up to that quality of machine work! However, seeing your steam lorry has given me an idea. What about the idea of a paddle steamer? Your 2 cylinder engine would be ideal, though we might be back to the question of weight again. However, I can imagine removable paddle wheels, and a single board with the engine and axle and then the boiler on a separate board. All could be light enough to lift out and into a car.

Regards

Pete

Re: Antidote to Cabin Fever?

Posted: Wed Apr 01, 2020 9:05 pm
by fredrosse
The originally proposed hull, with a loaded displacement of 780 lbs (0.35 long tons, very close to 0.35 Metric tonne), can make 4 knots with propeller drive at 0.45 shaft horsepower (0.34 kW). Best arrangement is 500 RPM with a 12 x 12 propeller.

These are rough numbers, I would think +/- 20%, but still useful for this discussion.

Re: Antidote to Cabin Fever?

Posted: Wed Apr 01, 2020 9:12 pm
by fredrosse
Previously mentioned, steam - electric drive using a trolling motor:

Direct motor drive would have several efficiency penalties, if driving a typical trolling motor, and they use very inefficient propellers, propeller efficiency drops from around 60% efficient (for typical appropriate applications) to around 40% (or excessive speed, small props with pitch to diameter ratios far less than unity). That implies that you need 0.675 horsepower at the prop shaft.

Plus there is motor efficiency, plus generator efficiency; taking these efficiencies of 75%, we need 0.675 horsepower at the propeller shaft, so we need 0.90 electric horsepower (672 Watts) power input. With a 12 volt system, this is 56 Amps!

Neglecting any electrical inefficienties due to wiring, switching and controls, which is reasonable, with proper design, we now have to generate 672 Watts electric power, with a 75% efficient generator, 896 Watts shaft power must be input, which is 1.2 shaft horsepower.

So the result here is to use conventional reciprocating steam engine drive. (Unless you are building large oceangoing dredges, that can put significant power to the dredge pumps while dredging, then all the power to the props when running offshore to dump the dredged material - Steam turbo-electric drive.)

Cabin Fever Ramblings.

Re: Antidote to Cabin Fever?

Posted: Thu Apr 02, 2020 10:14 am
by dampfspieler
Hi Pete,
.... How heavy would it be in operating condition?
~ 20 kg

A paddle wheeler is an interesting option - the engine-boiler-unit could be removable like steam folding boat "CALYPSO".
I think patented paddle wheels are more effectively than the shown. The WESTBURY drawings can easily be enlarged.

Hi Fred,

thank you for calculations, i think you are right and it is helpful.

__
Dietrich

Re: Antidote to Cabin Fever?

Posted: Fri Apr 03, 2020 2:52 pm
by TahoeSteam
Dietrich, perhaps something more like your model Ofeldt boiler would be more lightweight and appropriate?

Re: Antidote to Cabin Fever?

Posted: Fri Apr 03, 2020 4:25 pm
by PeteThePen1
Thanks Fred for the data. That clearly brings the 'flights of fancy' back down to the ground. Direct drive must be the way to go.

Thanks too Dietrich for your input. The Westbury two cylinder paddle steamer engine articles from Model Engineer can be downloaded free of charge here: [https://www.model-engineer.co.uk/sites/ ... team-1.pdf]

The plans, which look as if they come on a single sheet (groan!) are available here for GBP £12.50 [https://www.sarikhobbies.com/product/di ... cba1185463] EDIT - Opps! I had not spotted the hot link in Dietrich's post. It seems that the Julius de Waal version can be download free of charge. Sorry Dietrich, your link is much better than mine.

Given what you folks who post on this site can do, I imagine Dietrich's suggestion of scaling them up would present few problems. I think that the Model Engineer article says that the engine is for a 6ft boat. Unfortunately it seems to make no mention of the overall weight of the finished model.

Thanks for the suggestions. I do like the paddler idea.

Pete

Re: Antidote to Cabin Fever?

Posted: Sun Apr 05, 2020 3:08 pm
by Mike Rometer
fredrosse wrote:
Wed Apr 01, 2020 9:05 pm
The originally proposed hull, with a loaded displacement of 780 lbs (0.35 long tons, very close to 0.35 Metric tonne), can make 4 knots with propeller drive at 0.45 shaft horsepower (0.34 kW). Best arrangement is 500 RPM with a 12 x 12 propeller.

These are rough numbers, I would think +/- 20%, but still useful for this discussion.
I calculate (but that is Very dangerous!) that a 1.25" square twin would give over 0.5hp on 100PSIG, and a 1.5" square single a bit less, but still on the plus side of Fred's numbers.

:?: Would there be enough clearance for a 12x12 prop?

Re: Antidote to Cabin Fever?

Posted: Sun Apr 05, 2020 8:18 pm
by dampfspieler
Hi Mike,

a friend runs a canoe with a 38 x 38 mm (square 1 1/2") single and a VFT-boiler like mine. The prop has a diameter of 220 mm and a unknown pitch - it comes from a 2 hp outborder.
He steamed it on the Moselle river.

Here is a video - https://youtu.be/3G_ukzzOCZg

--
Dietrich