Lord Nelson

[96RAF]

Is that a proprietry injection valve Ken or one nicked from a football pump. Neat fix for a simple problem.

 

For a loco that wasn't going to need many moves away from the donor chassis, you seem to be sailing fairly far away at the moment.

 

All looking good so far. Looking forward to seeing how far you get on a ‘tank full’.

 

Rob

[gowest]

Hi Rob

remember the days when you could fit valve rubber to the valve on your bike wheels well that's the idea which I have used many times and it works fine see the not that good picture here of my 9f with the very small hole between the two large chimney holes as the oil injection poin.

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[gowest]

Having had problems with the motor control board on the GER S69 engine detail on the forum live steam here I though why reinvent the wheel when its already been done so looking back through the pages on the subject of motor control I have copied the pages from that job to this and will start putting something together. These pictures and drawing are from the S69 engine

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This is the diagram of the parts that went to build the electronics for the S69 so a little change maybe here and there but the same electronics can be assembled to fit under the cab floor.

[gowest]

Now I need to find space for the electronics one way to fit these different parts into a small space is to split them up.I have made 2 small PCB’s one that will fit on top of the servo motor and the other under the cab floor as described before.Lets take the small PCB that will fit on the electric motor, this board will have just the flashing light parts and the connections for the power to the supper heater and the connections to the servo motor . This board is shown in the picture here you will notice that it has spring clips to clip onto the motor the track side will have a row of pins to this a small inline socket will complete the connections from the servo control board./media/tinymce_upload/47cf7f5589a4bdee849aa5295bf3ba10.jpg

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You can see the board in place on top of the motor should this area have high levels of heat generated it will not have any heat sensitive components here so will not matter or cause a problem.

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The printed board in the picture here is the servo control board this new printed board will fit under the cab floor and have a plug which will plug into the PCB on top of the servo motor connection point for the motor and heaters and the flickering light LED.

Here I hope you can see the parts and how they all come together so will start with the body removed

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No 1 is the connecting board this has a row of pins which the lead from the motor control board plugs into this small plug also has the flickering LED  No2 is the plug. No3 is the control board. No4 is the flickering LED./media/tinymce_upload/bbe2f9599f3b9c0831714ef7f37e929e.jpg

From another angle you can see the row of pins sticking up. The wires from the supper heater and motor and the regulator switch are all soldered to this small board.

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Here is the cab floor and the back of the boiler with the control board and its wiring and plug.

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With the control board just visible under the cab floor and the 2 black wires which will be the connections to the tender.

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Viewed from the other side with the plug ready to fit into the loco connection board.

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And finally with the cab floor in its right position and the fixing screw to hold it all in place

[96RAF]

Well planned and executed Ken.

A lot of necessary stuff in not much space.

Rob

[gowest]

Rob

for others undertaking a rebuild and to make life easier they can use the Hornby printed boards and like the Hornby engines fit them in the cab. I have built new boards to fit out the way as I want the engine to look like a model of the real thin.

Colin very interesting about the coal levelling my father once told me of coal that had fell into some points and stopped the points closing properly this would mean that if the point motor did not complete its travel a locking pin would not locate properly and the signalman would not get the correct light on his panel. This meant my father checking out the points to see what the problem was if it was coal it could be cleared and the points work ok.

[gowest]

The safety valve extension has now been made up and fitted and should let the steam out of the right places I hope.

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More details are now added to the body like the 2 vacuum valves on the top of the smoke box and the cab has its driver sitting on his wooden seat and fireman shovelling away keeping up a good bed of coal with no air gaps which was a real skill on this engine as it had a long firebox with a front great area hard to see.

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A few more details to the back of the boiler like the pressure gages and maybe the water gages and that should finish the engine.

Now the electronics are finished and look to be working ok the engine needs a few test runs with it front bogie and the body in place to prove that these changes to the Hornby A3 engine will not throw up any problems once this mile stone has been crossed then its the tender that needs building.The paint and transfers have all been ordered so that when reaching that stage of the work there will be no hold ups.The name of this engine will be Sir Frances Drake as I live in Devon and so should be a local hero.

The Tender

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The tender I’m hoping will carry more water than the A3 and A4 engines which is what the original design for these tenders were for as an express engine the last thing you wanted was to keep stopping to top up the water tank.Many things have to be taken into consideration when building this tender .First how will the water tank fit in the available space how can it be built so that when it comes to servicing the body can be easily removed with a couple of screws. Also what type of connections to the wheels for the power pick ups. I think its with the wheels that I shall make a start. If I machine out the centres of a set of Hornby tender wheels I can then fit some spokes in the wheels so that they will look like the proper tender wheels for that class I have done this operation on a few locos now and it works out ok the last engine to have this idea was the S69.

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The tenders for the Lord Nelson class were 8 wheeled tenders holding some 5000 gallons of water and the wheels set were assembled on bogies and mounted as articulate moving independent units.

Unlike the A3 and A4 tenders where the boiler is mounted on the tender frames insulator this insulator needs to be made from a high melting point plastic.But on this SR tender the wheels sets are away from the heat of the boiler the plastic insulator that will go to make these bogies will not suffer any heat distortion

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Once  a drawing was sketched out in a drawing program it was then converted into a 3D file to be printed on my 3D printer

Below is the 3D printer making the first insulator for the tender bogies this when finished will need to be check out for the correct fitting and if any changes are required I will need to do them and re print it.

When the final design fits OK then the bogie units can be built up.

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I have drawn up what I think these bogies might look like when finished with the connections to the tender heater.

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The tender body has a small coal area in the front and a large section at the rear which is the end of the water tank on the full size engine.To make use of the complete area within this tender the hot water boiler will need to be made in 2 sizes the front section can be a complete round tank like in the Hornby engines while the rear section needs the smaller step so that it fits under the tender water tank top as in the drawing here.

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[96RAF]

I see you use SketchUp Ken. I like that app and its free unless you need all the top end bells and whistles. It also outputs to the 3-D printer, which I may one day decide to buy.

 

This loco appears to have had a few head-scratchers but as usual you have made it look very easy.

 

I like the oval part of the boiler, than should preclude any stress raisers in the pressure vessel. Will it steam OK with the heater element in the shallow part and a large mass of water in the tall part.

 

Appropriate choice of name for the engine.

Rob

[gowest]

Rob

I'm thinking that I could put the heater in the other end of the boiler but might mean moving the steam outlet pipe so will stick with the drawing above. A new idea is to fit the heater directly in contact with the water as these heaters are made of stainless steel will not rust what is needed is a compression gland with a rubber O ring to keep the water and steam in the tank in the Hornby set up the heater is set in a tube soldered to the tank so the heat has to pass through an air gap be it very small then through the tube to the water. By heating direct to the water it should heat up quickly and as heat rises the hot water should move to the larger part of the tank while the cold water will slide in under the hot towards the heater but we will see.

yes for any one wishing to try a free drawing program Sketch up is a good starting point you can play about and draw up things and you don't need a 3D printer just to see how it works.

Ken

[96RAF]

Good idea with the direct heater element Ken. I'm not sure why Hornby went for the double skin version in the first place. Yours will certainly be more efficient, providing the pressure gland can take the strain.

 

After all your household immersion heater carries mains potential into a single skinned enviironment, although my hot tank tank has a sacrificial anode which rots out before the other dissimilar metals in the tank start to corrode.

 

Rob

[gowest]

As fellow Hornby live steam operates will know a little problem that some times pops up is the front bogie shorting out on the cylinders and so the first steam runs with the bogie fitted came up with this problem as the wheels that I was using were more like the right size for the model but despite moving the wheel assembly forward or back ward this fault still came up but only some of the time. So to over come this a set of the Hornby A4 wheels were fitted to the LN bogie frames and this cured the problem. 

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You can see in the picture that the front bogie has one red wheel and one silver wheel the red wheels were from the Hornby Mallard.

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With the body fitted to the chassis as in the picture here some steam tests were carried out.

To start with the safety valves were tested that is to say that the steam that came from the inside Hornby safety valve exited from the right place the 2 brass valves on top of the boiler.

I also note that Hornby’s engine shed are producing a Lord Nelson class engine and very fine it looks to best of all they will be giving one engine the name Sir Frances Drake great minds think alike maybe.Need to check out the flickering light I think the LED may have packed up might be due to too much power or too much heat? But as the test runs went well it looks like the tender is the next job.

[gowest]

ive been testing out a new switch idea to improve the flashing light idea.

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Above is the new layout for the flickering light using a steam pressure switch, this is an idea i had to improve the point at which steam starts to move the engine off.

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I hope you can make out the parts and how it works, by this drawing of my idea.

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In the picture here you can see the standard oil tank which was fitted to all A3 Hornby steam engines.This is the square brass cover uppermost in the picture with the 4 screws holding the cover on and the black line is the sealing gasket.

How it worksThe idea behind this new switch came about because its hard to set the red and green lights or my flickering LED to a point that would give an accurate indication as to when the engine is likely to move off. most live steam operator will know the problems with the 2 position switch on the A3 and A4 engines.With this mod to the oil tank when the regulator is opened steam enters the oil tank from the main steam passage see diagram.The pressure builds up in the oil tank and this increase pressure will deform the rubber diaphragm to the point that it pushes on the brass contact strip depending how sensitive the adjusting screw is set the contact will make a connection with the end of the adjusting screw thread completing the circuit and in my case make the flickering LED much brighter so warning you that steam has reached the cylinders and an further opening of the regulator will cause the engine to start to move (you hope)

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In this picture is the new oil tank cover with the pressure switch built into it and a wire taking the connection to the flashing LED.

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A break down of the new parts i have done a few steam tests and it works fine 

[96RAF]

Brilliant idea Ken.

Nicely made and even nicer when it works exactly as designed.

Rob

[gowest]

Hi Rob

i have been thinking of this for some time and as I thought I was a new build how about a new idea for the lights 

l know its a branch away from the Hornby design and others maybe would need to stick with that but if I think a change might improve things related to the control of these engine then let's see. The only think that let me down was the insulator which I though might as it was made of Perspex and melted only after 3 runs so did get the testing done of this idea, I bet you must have come across lots of high temperature stuff in the RAF which is not readily available to the public.

l have some high melting point plastic on its way so will try that or i do have some PTFE but this tends to expand when hot.

added a capacitor to the Filckering LED in the drawing above and that's given it a better DC supply And works fine might try a 2k2 resistor as it looks a bit bright on full power as against the glow of not moving light.

apart from that things are going ok  ( I should not have said that) I now have the transfers and the paint turned up the other day will try a few more steam runs with the body on and then it's the tender to build.

[96RAF]

Ken

I would start with old fashioned paxolin or bakelite sheet if you find any, but the stuff veroboard/stripboard/pcbs is made from is soldering iron resistant so may be easier to get hold of and you could leave the copper on or etch it all off with your chemicals. Then there is Kapton tape, a few layers of that.

Rob

[Rog RJ]

Have a look at this thread http://www.model-engineer.co.uk/forums/postings.asp?th=101184 

[gowest]

Hi Rob

i can't find my box of paxolin rod or lump paxolin in my work shop did try Bakelite but it kept breaking up when I tried to thread it 5/32x40

to screw into the new cover

have sent off for some KEEP 8mm rod so will have a go with that as it's a high temperature plastic did make a new insulator with PTFE for some more steam tests which should be ok for now.

Colin

would be great to here from your father to see what he has to say on the matter as ideas that you might not thing would work just might I'm thinking of the Cornish tin mines when visiting an old pumping engine that bloke there said that they tried loads of ideas to make the valve on the water pump in the bottom of the mine and the only think that worked was hippopotamus hide which didn't break down in the water 

As for the engine I'm thinking before 1939 in malachite green with loads of lining out it has the snake deflectors and large chimney and the 2 snifter valves but if I've got it wrong no doubt you can point it out. It's like I was watching Dunkirk the other night all looked ok till the end of the film with the soldiers on the train and the seats look to have the wrong upholstery and the main window looked like double glazing with aluminium frame and fittings.

Ken

[96RAF]

Try this place Ken

 

I remember having some nylon rollers fail at work - they melted under load, so we had some made from Nylon 6/6 which was hard enough to wear well and heat resistant.

 

Rob

[gowest]

Thanks for all the above will check it out 

ken

[gowest]

Still not happy with the small red A4 wheels so I bought a Hornby front bogie from the internet these are a little larger and look to be the correct size I think.

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In the picture you might be able to see that I made up a spring fixture arm from the bogie to the engine chassis which is in 2 sections one to the bogie frame and the other as a floating load bearing spring which helps keep the bogie wheels in contact with the rail better and takes a very small amount of weigh off the front of the engine

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With the new bogie wheels in place and its new springing idea it was time for a few steam tests with the engine and travelling at speed over points and crossings it didn’t put a foot wrong.

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Running the engine with the oil valve system does make life a lot better than removing screws that tend to get very hot after a run or two.

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As I get the engine ready for some tests with a coach or two the crew look as if they have a good fire in the boiler and pulling a load might not be a problem.

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With 4 coaches it ran well might need to clean the track and reset the valve timing as it seems a little bit out the safety valves lift on the engine and steam pops out the brass loco valve so think I can move on to the tender.

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With most of the tender body built and thought maybe might make a start on the water tankLots of question here how much water will it hold will this larger area heat up properly will it steam will it take longer to reach boiling point will a small amount of lagging retain the heat thats generated I suppose we will find out as the tender comes together and tests are carried out.

The air tanks are not going to be used from the kit as they are made from solid white metal and adds a lot of unnecessary weight to the tender so I will make them from brass or aluminium we will have enough weight with the water tank.

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Just put the brass tube I had in the body and it looks to be the right size just needs to be made to fit in the available space.

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The new drawing of the boiler and how it will look I have built boilers like this before and as they operate on 30 psi I think it will work ok 

[96RAF]

Ken

I take it from the boiler drawing you are going to try the direct heater rather than the standard in-tube one.

Its all looking very good and progress proceeds at a pace I fail to achieve with ready made plastic parts.

Rob

[gowest]

Hi Rob

yes I will be continuing with the direct heat idea but have come across a problem will explain later on to day I hope?

ken

[gowest]

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Now work on the new boiler started and the tube was cut to length that will leave space for the steam out let pipe and space at the rear of the heater connections and a working oil lamp which is built on a small printed board inside the tender body and a fibre optic cable fed through the body to the oil rear lamp on the back of the tender.

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The ends of the tube were counter bored with a step so that the end covers will locate better and once heated up for soldering the covers will not disappear down the tube. The marking out in blue makes it easier to see the lines on the brass tube so that the next stage of cutting the step which will allow it to fit in the tender body better and keep the volume of water to the maximum.

You might just make out the counter bore in the picture above.

With the rear section cut away leaving the step section a little more clearly now as to what this boiler will look like plus the 2 pilot holes for the safety valve and the water filling screw positions now drilled in place work on some of the other parts can be made up.

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The top cover plate with its 2 bent ends this covers was made from some 20 swg brass sheet then all the other major parts to the boiler need to be made so that the number of heat ups can be kept to a minimum.

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The front end cover with its copper pipe that will carry the steam from the tender to the engines supper heater.On the Hornby engines an air gap area is provided for the steam to collect in but on this boiler there is no air gap so the water will fill right to the top using up all the available space within the boiler. This has never caused any problems with running the engine as any water that should travel down the pipe work soon turns into steam when it enters the supper heater.

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I thought that the end of the Hornby heaters were sealed off with a metal cap but have just seen that they are just filled with a heat proof plaster which if I try my idea of fitting the heater so that its in direct contact with the water it is most likely that this plaster will break down and water will enter the element and this will then break down and fail. To over come this problem I will dig out part of this plaster and make a blanking plug as in the drawing here and press this in the end of the heater so sealing it from the water.

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The only problem will be that this makes this heater a one off now and should the heater need replacing then this steel end cap will need to be removed and refitted into the new heater.

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A new idea for the heater fitting into the end of the boiler is to use a much simpler sealing compression system still using an O ring as the seal and making up a sandwich to compress the O ring around the heater and give a good gas tight fit the reason for the change is the gland nut idea leaves the heater element to far away from the bottom of the boiler and in so doing reduces the ability to boiling the last few drops of water and also increases the distance from the thermo switch which fit to the out side of the boiler for the low water detection and over heat alarm. The new design clamping arrangement has been drawn up so that the heater will be close as possible to the bottom of the boiler.

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With most of the parts made it will soon be time to solder them all together.

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With all the components made including the new heater sealing parts its time to solder them up and see how much more water this new tank will hold?

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With the soldering job done the and sat in the acid for a few hours to remove old flux and carbon the fittings were screwed in place to see what the finial assembly would look like as the filler screw and safety valve were going to end up under the coal in the tender I didn’t want this to appear too high this would give the wrong look to the coal heap in the tender if it ended up higher than the cab roof.

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The only part left to fit was the heater element this placed in the right position and its rubber O ring also in place the back end cover was fitted and the 2 10 BA nuts tighten up this it was hoped will seal the heater and the boiler fitting so that no water was going to leak from around this area?

A test on water capacity  between the Hornby boiler and my boiler was carried out and my boilers hold 10 ml more water so might give some 40 minutes running time but we will see what is achieved later with some test runs in steam. 

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With the boiler in the body it fitted like a glove and no problems showed up so the boiler can be fitted to the chassis and the bogies can be built and fitted to the chassis with the wire pick ups to the tender heater and the connections to the loco worked out. I think its going to be a case of some printed board for the basic termination points and the heater temp switch fixed to a small box under the chassis. But this is all to be worked out as the job progresses

[Rog RJ]

Nice work Ken.

[96RAF]

Amazing progress Ken.

Ref the heater element you could run full strength Araldite in there. I used to use it to ‘pot’ and bombproof slot car motor armatures. It goes runnier if its warmed up (to help run into the pole windings) then sets like concrete.

Is that soft lagging around the element or more of the plaster?

 

On a different tack I wondered about other micro elements and a Google came up with many hits, but this one may be a possibility.

http://www.mod-tronic.com/Minco_Flexible_Heating_Elements.html

Some are flat, flexible and self adhesive so could stick on the outside and get round several problems, e.g. gland seals, heating the last drop, etc. I will have a better look at possibilities later today as after a trip to the shops.

Rob