# Small Oscillating engine with gear box.



## Tony Bird

Hi,

I have done a bit of R&D for a friend on a gear box for a model paddle boat.  The steam engine that will power it is a single acting oscillator with an 8mm bore and 16mm stroke it is based on a Mamod size I think; so there isn't a lot of power to play with.  A successful gear box with this size engine has been made using spur gears but a more compact one using a worm drive was desired.  A couple of gear boxes using heavy brass gears have been made but they had too much friction.  The hull to be driven is basically to the Mini Vap 50 rule it being just over 20" long and works quite well using the engine driving the paddles through a spur gear box.

The gear boxes that have too much friction.





So I am trying nylon gears.





The spur gear box using a 16:1 ratio drove a pair of 3.1/2"paddles easily.   So a prototype engine and wheel and wheel gear box was made.  The prototype gear box was designed so it could easily be made with different gear ratios.  First an 18:1 ratio was tried; having a slightly lower ratio was used to overcome any higher friction that a worm and wheel gear box might have.








With the engine support fitted.





A cylinder was made using a K&S brass tube.























A balanced flywheel was made.





The steam ports were drilled in the port block using a jig.





As there is no means of lubrication in the model boat a long aluminium piston was used.  I have found the combination of an aluminium piston working in a brass cylinder works well with saturated steam.





Checking the piston steam port clearance.





Checking the finished engine and gear box using steam.





With a boiler pressure of 20 psi it was found quite difficult to stop the engine by gripping the output shaft.  So it was decide to build a lighter streamlined version using the same gear ratio of 18:1.

For the engine/gear box frame some 1" square tube with 1/8" thick walls was used.








The same cylinder, piston and flywheel sizes were used.





The finished engine.











The two engines/gearboxes built.








The gears used were supplied by S.H.G. Models; the push fit gears are more concentric in use than the gears with bushes and were used on the second engine.  The cost of the worm and wheel was £3.50; I quite like using well made nylon gears they are quieter running than brass and seem to wear very well.  I have some 20 year old model railway locomotives that regularly have a lot of use which whose nylon gears are still in good condition.

The second engines port block has been designed if necessary to be large enough to take a double acting cylinder.  Using a thick wall square tube to make the engine mount means that bearings dont have be used.

Video of prototype engine in steam.

https://youtu.be/VmcpC5wAd5o

<iframe width="420" height="315" src="https://www.youtube.com/embed/VmcpC5wAd5o" frameborder="0" allowfullscreen></iframe>

Streamline engine in steam.

https://youtu.be/0hNhS5_UVF4

<iframe width="420" height="315" src="https://www.youtube.com/embed/0hNhS5_UVF4" frameborder="0" allowfullscreen></iframe>

If there are any questions please ask; but from tomorrow I am away for some time to where the internet isn't that reliable so it might be a while before I can answer.

Regards Tony.


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## Tony Bird

Hi,

I have decided to make a hull to check out the engine and gearboxes made.  I have had some plans for a Murray River paddle steamer for some years and they are being used as a bases for the test hull.  I have had a meeting with the friend who is going to 3D print some paddle wheels for me.  He has worked out how the paddles will be constructed; a very simple design with 12 blades.

I have started work on a prototype hull.  The plan of the hull has been photocopied and has been increased in length to 54 cm to give more buoyancy and still still be less than the 50 Mini Vap rule.

The plain section on the drawing is the extra length.





A half section template was made from thin plywood it could have been from card but I didn't have any. The half section plan glued to the plywood.





The Half section was cut out.





And the paper removed.





The hull to be made is for testing and for positioning the boiler, engine in it so I am using timber that I have to hand.  The hull shape will be to the extended drawing but the construction will be as open as possible to allow easy distribution of the various parts of engine boiler etc.  The original instructions with the drawings specified balsa wood for construction.  I don't have any balsa wood and for steam use a more robust hull might be an idea.  So one of my usual sources of timer was used.





I don't make many boats from scratch so my constructional techniques tend to evolve so there are probably better ways of doing it.  The coping saw was fitted with a new blade and cutting was started.





The two halves of the bottom of the hull were glued together.





Being a metalworker the result was filed rather than planed, I do have a plane somewhere.





To give the most access the deck was modified from the drawings.





The two sections of deck nailed together for filing.





The ends of the deck were glued and slotted for a piece of plywood foe extra strength.





The drawings called for formers to hold the bottom of the hull and deck apart but to give maximum access pillars were used.








That is as far as I have got with the hull.

Regards Tony.


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## Blogwitch

Very nice indeed Tony.

I thought minivap was dead and buried years ago as I designed and made V-twin engines for them just after they started to be used. I gave about a dozen sets of parts to a friend many years ago, unfortunately he has now passed away and I don't know what happened to them.

I did modify (made it easier to make) a French designed long stroke engine which I sold for a few years, but I also made two paddler engines from the same design. On 5 psi, the two output shafts could raise a breize block on it's  shaft at the max revs of 100 rpm. Very powerful indeed, and should easily power a 50" to 60" paddle tug. I still have one of each in my posession should ever I take up model boating again.

Both the vertical and horizontal versions.








John


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## Tony Bird

Hi John,

A pair of very good looking engines you have made; it would be nice to see them powering a model boat.

A bit more has been done to the hull more pillars have been fitted.








And a inner skin has been fitted.











The hull so far has been sealed and hopefully the outer skin will be fitted tomorrow.

Regards Tony.


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## Blogwitch

I made a total of 18 (in batches of 6) of the uprights and only two of the horizontal.

They are powering models all over the world (at least they were a few years ago), with not one complaint.
Stick with a simple design, make it to the best of your abilities and you can't go far wrong.
Where people go wrong with model boat installations, they make them far too complicated, with such things as gas attenuators, sight glass level sensing auto top up pumps etc, so they spend most of the time messing about with the steam plant trying to get it to run correctly rather than being on the water sailing. 
I sailed my steamer almost every weekend, summer amd winter for ten years with no breakdowns, just a piston ring change every now and again to keep the power up and lots of steam oil. 
It looks like you are aiming for the same thing.

John


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## Tony Bird

Hi John,

I agree the simpler the better, less problems!

Today I skinned the hull with 1/16" (1.5mm) plywood.

Both sides being skinned at the same time.






The bows were done separately this is the second one being glued.





The hull as it looks at the moment.













Regards Tony.


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## Herbiev

I thought i knew most of the Murray paddle steamers but havent heard of the Jennifer Anne before. Great looking craft so far.
I would love to build a scale model of the Marion.


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## Tony Bird

Hi Herbie,

Eris Kennedy the Australian who designed the Jenifer Anne in 2007 named her after his daughter and said that the model is representative of the type of paddle steam used on the Murray not a scale model.  Apparently the models first sailing was on the Murrumbridge River a tributary of the Murray.

Regards Tony.


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## Tony Bird

Hi,

I caught up with some domestic engineering this morning and did a bit on the hull this afternoon.

The hull had been sealed and hung up to dry yesterday afternoon.





This morning a displacement test was done to see how much weight there is to play with for the rest of the construction.








About 2.4 kg nearly 5.5 lb to get the hull to its water line.





A start has been made on the sponsons which will hold the paddle wheel covers.








A dry run with a boiler and engine.








The engine and empty boiler come in at just under 1.5 lbs so there is a bit to play with.





Regards Tony.


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## Tony Bird

Hi,

Today I did a bit of metal work along with some wood work.  I don't know what it does but the Murray River paddle boat has a very long stem post.  Presumably made of wood; for a model this looked a bit vulnerable so one was made of aluminium and screwed in place.








The large rudder was cut out of plywood and a hinge made.  The hinge is simply a couple of brass eyes screwed into he hull.  The rudder has a brass tube glued to it and is held between the brass eyes with a brass rod.  A slight kink in the brass rod stops it from falling out and allows it to be removed when necessary.





It was decided to make a drive system for the paddles so some bearing for the paddles shaft were made from some aluminium channel.  The 18:1 drive is by Mamod type spring belt and some commercial 1:1 plastic pulleys.





The model now looks like this.





A short video of the engine, gear box and drive running on about 8 psi of air.

https://youtu.be/9LiTdApba6Q

<iframe width="420" height="315" src="https://www.youtube.com/embed/9LiTdApba6Q" frameborder="0" allowfullscreen></iframe>

Regards Tony.


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## Blogwitch

If I counted correctly, it looks like you have about the right rotation speed (depending on pressure to the engine of course) of between 60 and 100. I used to have my feathering ones running at around 90 RPM.
People have them going too fast and they lose any of the efficiency that non feathering floats have.

So it looks like it is going to be a good one.

John


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## Mechanicboy

Nice work at paddle wheel steam engine and the hull who is unable to be sunk.


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## Tony Bird

Hi,

The paddle boxes have been made.












A steam test was done and the boiler makes enough steam for the engine and probably any other engine that is likely to be fitted to the hull.

A video is at:

https://youtu.be/7NdLD90JG7U

In Old South Wales the sun is shining and may it do so for the rest of the day as I will be playing with trains at the CMES.

Regards Tony.


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## MichaelWilliams

Waverley

One of my treasured memories is of an unplanned journey on her from Bournemouth Pier to Poole Harbour one evening many years ago .


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## Cymro77

Tony, I just found this posting - I just love your work. Thanks once again for posting an intriguing concept.
DW


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## charlesfitton

Hi Tony;

I really like the cooling "tower" in your first photos. Excellent use of questionable taste.

As to the tall stempost...maybe to push aside large tree branches?

f


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## Tony Bird

Hi Charles,

*I really like the cooling "tower" in your first photos. Excellent use of questionable taste.
*
You mean my desecration of a fine Indian hand engraved brass ogee specimen vase that was worth a fortune?  I think it was £1.50 in a charity shop.

*As to the tall stem post...maybe to push aside large tree branches?
*
Could be; some has suggested that it was a steering aid helpful on winding rivers?  Maybe both?

Not a lot of progress on the hull some combing has been put around the deck and some undercoat applied.











I'll have to make a start on some paddles!

Regards Tony.


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## Tony Bird

Hi,

Today I did some more painting and made a paddle wheel from some 1/16" aluminium sheet.






















Regards Tony.


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## Tin Falcon

what program did you use to generat the gears
Tin


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## Tony Bird

Hi Tin,

*What program did you use to generate the gears?*

The plastic/nylon? gears are a commercial product available from technobotsoline.com the cost of the gears pulleys and belt was a little under£7.50.

When I repaired clocks for a living I cut gears in brass and steel but no nothing of the production of plastic gears.

Regards Tony.


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## Tin Falcon

well ok then.  I thought you had gone to the proverbial dark side and purchased a 3d printer. 

Tin


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## Tony Bird

Hi,

I did some more on the paddle boat today.  I have decided it is as far as I will go with the painting, it could be a lot better, arthritic hands don't help when sanding!

A drip tray for the engine.





A simple stand was made.





The paddles and engine fitted.





The paddle boxes fitted.








It has been run on air again a video is at:

https://youtu.be/xUkX8HcZXmQ

Regards Tony.


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## Tin Falcon

Another fantastic build tony thanks for sharing. 
Tin


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## Tony Bird

Hi Tin,

*Well OK then. I thought you had gone to the proverbial dark side and purchased a 3D printer.*

Alas no I don't have the ability!  Our son made one and his children use it to make name badges and the like.  It is easy Granddad all you do is........

I did some work on the boiler today.  The boiler was intended for a boat and it was built a few years ago.  As designed the steam was going to a reversing valve/regulator before going to an engine so the boiler has no regulator fitted.  The boiler is a pot boiler with heat exchanger pins and can be fired by Sterno or a ceramic gas burner. 

A constructional photograph of the boiler showing the pins steam pipe and where the steam is collected, the steam dome when fitted holds the condensing chimney. 





The boiler and its Sterno tray before any further work was done on it 





As the engine is a single acting one and won't self start so there is no point in fitting a reversing valve.  If the model boat had been screw driven like a lot of the model steam boats made years ago by the likes of Bowman a regulator needn't be fitted.  But as this is a paddle boat I thought it might be wise to fit a regulator to try and get the best out of the paddles, it might turn out not to be necessary. 








As the boiler looks in the hull. 








As can be seen the whistle has been replaced by a top-up valve and the exhaust connected.  A lubricator needs to be made and fitted and the boiler secured in the hull before a steam test can be made. 

Regards Tony.


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## Tin Falcon

> Alas no I don't have the ability! Our son made one and his children use it to make name badges and the like. It is easy Granddad all you do is.......



Well just maybe you can get the grand kids to print you some gears. It is quite easy. I started a thread here as to not side track this one.Plastic Gears Thread

Tin


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## Cymro77

Tony,  
Looking at the photos of the hull construction, I see what appears to be a second layer on the bottom.  Did you double up the bottom? DW


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## Tony Bird

Hi Tin,

*Well just maybe you can get the grand kids to print you some gears. It is quite easy. I started a thread here as to not side track this one. Plastic Gears Thread*

I had a look very interesting I wish I understood it.  We see our grandchildren in a couple of weeks I will ask them.

Hi David,

*Looking at the photos of the hull construction, I see what appears to be a second layer on the bottom. Did you double up the bottom? *

I cannot see what you mean which photograph?  The hull bottom is just a piece of 1/4" spruce wall cladding.

I thought you might appreciate the name as it is white and has a fire, it is also our eldest granddaughters name and the Anglicized version the title of our son's company.

A lubricator was made and fitted today.  I am not very keen on lubricators that have a drain I prefer them that need a syringe to empty them as they are not as messy to empty.  To allow the syringe draining tube to pass the steam pipe it is off-set when it goes through the reservoir.  This is easy to do as long as the tube to be drilled has been plugged with wood.  An undersized hole for the steam pipe is drilled in the reservoir at right angle to the tube, while the drill is still rotating in the tube is turned so the drill is at a tangent to the diameter of the tube.  The tube is then plugged with a hard wood and the exit hole for the steam pipe is drilled this pilot hole is then drilled to the size of the steam pipe.





The steam pipe marked with the position of the hole.





It can be difficult to drill the small hole in the steam pipe especially if it has been annealed.  What I do is to use a small round file to file part way through the steam pipe a the use a n old gramophone needed held in a pin vice to make the hole.  Sewing needle would probably also work.  Sorry it is a poor photograph of the result.





To insulate the boiler from the hull the modern equivalent of asbestos was used; it is the fire retardant material used as eves in houses.





This board was cut slightly smaller than the base of the boiler and cooking foil was attached either side of it.





Some brackets were made to hold the boiler in the hull.





The boiler was fitted into the hull and connected to the engine.











The engine has been steam tested with the boiler fitted in the hull,  I will post a video of it running when it has been down loaded.

Regards Tony.


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## Tony Bird

Hi,

A steam test video at:

https://youtu.be/jiSNmjoM6Fg

Regards Tony.


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## Herbiev

That should move along nicely. Great video and looking forward to seeing it in the water.


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## Tony Bird

Hi, 

Today I had to get one of my larger engines ready for its 4 year hydraulic boiler test which hopefully will be done this Saturday at the CMES.  That took most of the morning then we then had a phone call inviting us out to lunch, which was very nice so I have only had an hour or so's playing with the paddle boat.  I decided to give it a run in a test tank (plastic box).  First the hull was ballasted to its water line.  Paper templates were used and lead sheet cut to them.



 

Two sheets of lead at both bow and stern were needed to get the hull to its water line. 








The boiler was fired up and the engine ran in the plastic box.  Every thing seemed to work well and the engine under load was very controllable. 





I am not sure how far the paddle blades should go into the water they are ballasted to about about half their depth at the moment, even with the blades completely submerged the engine coped with the extra load easily. 








The video will follow when it is down loaded. 

Regards Tony.


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## Tony Bird

Hi,

Video at.

https://youtu.be/Nx-TX9uo710

Regards Tony.


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## Herbiev

Looks like you have enough grunt there to tow half a dozen water skiers


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## Cymro77

Looking great Tony!  Thanks for sharing.


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## Tony Bird

Hi,

I have been into town to get some R/C gear from a model shop and on returning home set about fitting it into the hull.  As for the moment the R/C will be for rudder only and space is a bit limited a box for the R/C was made.





All the R/C gear fits in the box, which will give limited protection from water.





The weight of the batteries etc. will replace some of the lead ballast, the R/C box is held into the hull with a couple of brackets.





The rudder fitted.








The model is now about ready for checking out.  A tank for the waste oil still has to be made and a box to transport the will also have to be made.  So with a bit of luck and good weather it shouldn't be long before the model has its maiden voyage.

Regards Tony.


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## Cymro77

Hi ho, hi ho it's off to the lake we go!!  That is going to be one fun outing!  Everything is so neat and precise one cool boat!


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## Tony Bird

Hi,

In theory the model is ready for its maiden voyage.  A tank for the separated oil has been made and fitted, it will be empted using a syringe and the hull has been re- ballasted to compensate for the weight of the R/C.  I am in the process of making a box to transport the model in.








Regards Tony.


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## Tony Bird

Hi,

Yesterday I had the opportunity to try out the steam model of a Murray River Paddle boat I made in a very small boating pond. A video is at: 

https://youtu.be/K2IOAPcVOZY

I was quite pleased with the result as I have never made a model paddle steamer before.  The model has a reasonably small turning circle but the paddles do not seem to absorb much of the engines power so I am wondering if larger or more paddle blades would improve its performance.  Any suggestions?  Maybe for the models next run I will try with the existing paddles lower in the water.

Regards Tony.


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