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[JimG]

Trevor, Wren still make a turbo prop, based on the smaller mw44.
The Jetcat marine turbine looks as if it is based on the air turbo prop with extra gearing although it does seem to be designed for speed not for scale. More suitable for an unlimited hydroplane rather than a battleship.

Jim

[Mad_Mike]

Looking on eBay I found these. According to the item description. They work at 0.3 MPA which is about 45 psi. Autoclaved by steam and capabale of withstanding 135 oc. 18 to 25k rpm. Which is about 540 motor speed. 5:1 gear reduction on it. Can't see why not

 

[Mad_Mike]

http://vi.raptor.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=221147777393&category=31458&pm=1&ds=0&t=1461585125290

[dreadnought72]

Just to add to the mix. Dreadnought, the real one, on full power trials (9th October 1906):


SHP = 24712 (18.4 MW)
Speed = 21.05 knots
Coal Consumption = 16.66 T/hr (139 MW @ 30 MJ/kg)
Steam Consumption = 15.3 lbs/shp/hr


The coal-burning Dreadnought was therefore about 13% efficient in terms of turning the energy available in coal into motion. The model will be less efficient again - smaller props, different Reynolds Numbers, smaller diameter turbines - the list is long. The only advantage you might have is by using propane/butane: it has 150% of the energy by weight of coal.


If you needed (say) 100W at the prop end for a scale-like 3.5 fps, at 13% you'd be needing at least 770W and presumably a lot more (2kW? 5kW?) at the burner end. It's heading from kettle to house boiler territory.


Is this do-able? What sort of watt outputs can you get in model boilers?


Andy

[warspite]

But wont the scale effect of the water be negliable as she would have a lower resistance due to the shallow draft ?

[ballastanksian]

Given the small diameter of the 'turbines' Dr Rooks intends to trial, will this offset somewhat the issue of capacity needed? Also, will heating the turbines from the steam passed through them make them more efficient?

There was a super speed boat model shown for sale on here a few months back that had a flash boiler running a V6 or 12 engine and wonder if a flash boiler can generate enough steam for that collection of cylinders, a similar flash boiler could generate enough steam to run four small diameter turbines.

[rfurzer]

See my post about Turbo-electric drive. Make an interesting steam turbine warship with a nod at least to real scale technology, solve the gearing question, allow "emergency" propulsion with batteries. a winner?


https://en.wikipedia.org/wiki/Turbo-electric_transmission


http://www.navweaps.com/index_tech/tech-038.htm