Steam Turbines for models

[David WooleyParticipant @davidwooley82563]

On my resent visit north to Glasgow and the National Model Warship Weekend I came across some old Ship and Ship Model magazines a Percival Marshall publication of August 1934 kindly given to me by Steve Pickering . An interesting read but what attracted me most was the back page add for a Davis Steam Turbine available from the famous Bassett Lowke company . I'd witness flash steam hydros on Birkenhead water many years ago and they where amazingly fast well over 120mph . I could not help considering how useful a steam turbine would be for a model and how the likes of the one illustrated would work, just a thought as you really don't see many steam turbines.

[David WooleyParticipant @davidwooley82563]

[Kimosubby ShipyardsParticipant @kimosubbyshipyards]

Greetings Dave,

how we miss those Dortmund trips………

Couldn't help but notice not just the steam turbine ad you mentioned, but the one below for the Cutty Sark. I had access to volume II when I was renovating a Cutty Sark for a local restaurant over here. I was very good and gave it back to the owner who, sadly , has since passed over. I've no idea where those two volumes are now. Last seen by me about 1999.

Still, I now have enough details to search for them. Not that I want to build the clipper, I am just fascinated by the detailed drawings and such that they contain. Thanks Dave, maybe see you about at Haydock?

Kim.

[Tony HadleyParticipant @tonyhadley]

Couldn't help but research further the Davis steam turbine. In the F J Camm book, Model Boat Building (guess from the 1920's), this photograph showing the turbine used to power a Bassett Lowke 1metre boat, Streamlinia.

The relevant text from the Streamlinia item reads –

'Further experiments have been carried out, using the Davis Steam Turbine which gave good results. The " impulse " Multi-Velocity Turbine consists of rotor, casing and nozzle. The rotor used for this boat is a 2 in, in diameter and requires from 60 to 80 lb. pressure to drive a metre sized boat. It can be obtained, complete with friction reduction gear, jet and union, from Bassett-Lowke Ltd. This prime mover can be fitted to the boiler, and the only alteration necessary is a longer propeller shaft, which can be supplied to order.'

[David WooleyParticipant @davidwooley82563]

Hi Kim One of the fascinating aspects of the old Ships and Ship Models is its coverage of sail powered ships and the depth of knowledge shown , it may be ancient material but it remains a good read.

Hi Tony Thanks for the prompt answer to my question , I like the jargon " impulse multi -velocity turbine" I feel at home with that . I wonder how successful it really was .

Dave Wooley

[ashley needhamParticipant @ashleyneedham69188]

Not that I know much about live steam, but all I have read seems to indicate model turbines can eat steam at a prodigious rate without converting all that to rotary motion. One wonders if the old conventional boilers would have been up to the task? You last scan seems to show a reasonably large boiler but how many of these turbines were sold and how many were connected up to old Mamod boilers!

Ashley Below, a picture of someone making a single wheel Turbine using a home made (!!!) CNC machine. Wonder how the Davis was made?

[Tony HadleyParticipant @tonyhadley]

A more modern one from Model Boats magazine,1982 –

Another design was in the 1952/3 Practical Mechanics magazine for an easy build steam turbine to power their Vanesa design (by J. E. Jane). Looks ok too despite the heavy steam consumption.

Can't see the Davis turbine having a long life expectancy as the metals used at that time wouldn't have been up to a modern specification. The steam supply to a steam turbine needs to be superheated, saturated steam straight from the boiler will erode the rotor and break the vanes due to the suspended water vapour held within the steam. In a model, superheated steam can easily be achieved by routing the steam supply pipe (from the boiler) back through the burner. J. E. Jane suggests this method for his steam turbine design for Vanesa.

The last paragraph in this document explains in more detail –

http://www.systhermique.com/steam-condensate/services/troubleshooting/superheated-steam/

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

Hi all folks, i am new here in model boat forum.

I has Elmer turbine with ball bearing 4mm x 9mm x 4mm instead bronze bearing.

Here is results of testing with difference oil:



Here are the tests of oils and measured revolutions per minute:

Work pressure= Mobil ESP 5W-30 / Air tool oil / Diesel oil (fuel for diesel engine as lubricant)



1 bar= 4700 / 13230 / 17600

1.5 bar= 6200 / 17900 / 25700

2 bar= 11400 / 21660 / 31500

2.5 bar= 15500/26340 / 36700

3 bar= 18600 / 28800 / 41800



As i can see the ball bearing get less drag/friction with diesel oil as lucricant, it is sensitive for jet stream from nozzle. With high revolution above 15000, i can feel there are enough torque when trying to stop the turbine shaft.



Here is the steam turbine with reductiongear 10.2:1 under test.

Edited By Jens Eirik Skogstad 1 on 12/10/2014 14:38:24

[Mark Jarvis 2Participant @markjarvis2]

HI Jens

Your vidio shots show that a steam turbine certainly works, but is it a practical fitting in a boat? do you have the endurance even of a few minutes to be able to sail the boat???

Regards

Mark

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

Hi Mark..

I has not tried in the modelboat. The propeller sleeve is in lowest part of the gearbox, also no problem to install in the modelboat. The turbinehouse is easy to dismantle from gearbox with locking screw on gearbox when the gearbox is installed in the modelboat. Running time is about 15-20 minutes with this Saito boiler showed in the video. I learned out the 2 blade graupner propeller gave the better thrust than 4 blade propeller due too big diameter/pitch showed as in the video.

The oil in gearbox is critical due drag in oil caused by viscosity in oil, i learned the gear oil is robbing power from turbine and i tested miscellaneous oil. The recommended oil in gearbox: sewing oil or diesel oil as lubricant. The level of oil will be about 1:3 of the diameter of gearwheel for propellershaft. Under running, the oil will spread overall in the enclosed gearbox. No sign of abnormal abration in gear tooth or bearings.

I wrote about measuring results of the turbine in steam pressure and difference viscosity of oils, also the turbine ran without load.

Diameter of the turbine wheel: Do not make too large turbine wheel diameter due the revolution will be reduced with increasing diameter with same amount of steam and pressure. We need high revolution to produce enough torque out of the turbine before we are reducing to usable revolution for propeller with high torque with good thrust in water.

Gear: Use hard steel gearwheel to example from drill machine or similiar against abration due high revolution.

The plan i used to my turbine for modelboat as here.. **LINK**

[Master ShipwrightParticipant @mastershipwright]

Hi all

Here is an interesting book on model steam turbines by H. Harrison. Describes all you need to know about the background theory (in imperial units) and how to make them. A search on amazon.co.uk reveals that a version of it is available.

Martyn

[Mark Jarvis 2Participant @markjarvis2]

HI Jens

In your video shot it looks like the turbine is open on one side, in an installation would that be closed? does it alter your running characteristics?

In the link it also shows the turbine open???? is it a problem of build up of pressure in the housing???

Cant wait to see this project on the water, Awsom!!!

Regards

Mark

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

Hi mark, this was a test how the turbine worked with load in water, it was surprising to be good enough power without cover with exhaustpipe on the turbine house. When i am ready to complete the turbine house with cover with exhaustpipe to lead out of turbine house, then i will test on modelboat.

I has the copy of model steam turbines by H. H. Harrison. Very well expained how to calculate and build the own turbine. I prefer machined turbine vanes direct on the turbinewheel due risk to have turbine disaster showed as here: **LINK** Also i need high revolution to make more torque out of engine without disaster of turbine vanes.

Before i builded my first turbine, i think to have the Tesla turbine (vane free turbine wheel). But i was not sure how effective the Tesla turbine will be when i am thinking about how big pressure must bee and how much amount of steam. So I rejected the Tesla turbine and chose Elmer turbine since it is small and strong enough for a small steam boiler.

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

Download The model steam turbine as PDF here: **LINK**

[Tony HadleyParticipant @tonyhadley]

Here is the Model Steam Turbine from Practical Mechanics, November 1952. This was designed for use in the J.E.Jane designed model Vanesa. Not sure the turbine gave the required performance, as it was later replaced by an oscillator.

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

Nice article from Practical mechanics..

I doubt that the turbine reaches 50,000 rpm due to turbine diameter is 2 1/8 " (51.1 mm) and without ball bearings out of my own experience. Not much to reduce the useable torque via reduction gear. And boiler in the article is not big to produce enough pressure of steam to drive turbine. Improved slightly smaller diameter 30-35 mm and have ball bearings on turbine shaft + gear ratio 8: 1 to 10: 1. To increase the torque of the turbine before reduction gear: High speed and flywheel on the turbine shaft or rotor as flywheel with vanes. Avoid plain bearings. Of my own experience: From 15 000 rpm the torque will be better with turbine rotor as flywheel…

Edited By Jens Eirik Skogstad 1 on 19/10/2014 00:12:09

[Master ShipwrightParticipant @mastershipwright]

A model steam turbine plan and construction notes here **LINK**

Martyn

[Master ShipwrightParticipant @mastershipwright]

A stunning model steam turbine here **LINK**

Martyn

[D. jbParticipant @d-jb52802]

Hi Sir

[Tony HadleyParticipant @tonyhadley]

Deflinne,

Nice to see an original "Davis" steam turbine still in existence and in pristine condition too.

[Dodgy Geezer 1Participant @dodgygeezer1]

It looks to me as if the Graupner prop is being driven backwards. Is this the case, or is it just the video?

[D. jbParticipant @d-jb52802]

Hi Tony

this is the boat that goes with

[Tony HadleyParticipant @tonyhadley]

A lovely looking boat Deflinne, I am sure you must get a lot of good comments at the lake.

Here is an old photograph of the Bassett Lowke 'Streamlinia' model which the Davis steam turbine was originally installed. These models were approx. one metre long, so the steam turbine must have been a powerful installation. Apologies for the poor photograph, it's the best I could find. The Basset Lowke 'Streamlinia' was featured in Model Boats magazine March 2015 in the Flotsam and Jetsam item.

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

Posted by Dodgy Geezer on 11/12/2015 19:58:53:

It looks to me as if the Graupner prop is being driven backwards. Is this the case, or is it just the video?

Hi, it is right the Graupner propeller is running backwards since i has not the right propeller in this rotation direction in my steam turbine.

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