I suppose I had better explain my obsession with this locomotive -but it began 42 years ago and has gone downhill since then... I think I am about 35% of the way through building it, and it is the third G3 model that I have built. When I first proposed building it friends told me, "You're mad!" this same viewpoint was echoed by one of the model engineering firms that I approached and I got thee polite -but very firm refusals. The problem with this loco are the six driving wheels. I have had to devise a method of making the wheels, allied to this I propose a track with, (for G3), very tight corners due to my location on top of a hill.
This is the infamous, "Snowflake Wheel", that defines the look of this locomotive.
(http://www.cabbagepatchrailway.co.uk/neree1pic34.jpg)
The only bits turned on a lathe were the rim and the hub. The spokes are all hand sawn and silver soldered. Next Saturday is the Burton-upon-Trent Beer festival. The steel for the chassis has been: ordered, cut, and should be delivered on Friday. So, if we follow a similar patten the chassis plans, (plus beer mats for notes), will be discussed / worked on by a group of "madmen" during it!
regards
ralph
Rather you than me Ralph!
Can you explain the process please? Turn the centre first - hold the tyre in a jig, solder in the spokes, then finish-turn the tyre? I imagine all the bits are mild steel?
Mike
Looks an interesting project and I look forward to seeing the completed loco.
Not quite clear which loco it is from the message heading.
Is it NER No.13, the massive 4-6-4 (2-CO-2) which never ran?
Will you be installing catenary ... that might well be a 'first' for G3?
John.
I am first and foremost NOT an engineer!!! The tyre is first of all chain drilled on a mill and then most of the metal milled away to leave a square blank with a circular milled trough in it. The blank (a piece of 100mm sq BMS) is then clamped in a four jaw chuck and then attacked with a lathe tool to punch through. This leaves me with a round hole in square sheet, this is then turned out to 80mm dia. The spokes are made from tridents of 5mm sq steel.
(http://www.cabbagepatchrailway.co.uk/neree1pic31.jpg)
Each one is then pinned with 3mm titanium threaded bar, (a piece of scrap from RR!), and then brazed to the 25mm dia hub -which was turned down at one end to 13mm dia. It is going to be a working Quill drive too...
(http://www.cabbagepatchrailway.co.uk/neree1pic36.jpg)
The spoked hub is then fitted to the four jaw chuck and after some grunting the position of the cutting head is transfered to the spokes. They then have a dire attack of the angle grinder and bench grinder... The trimmed spoked hub is then CA'ed to the wheel rim and re-fitted back into the 4 jaw. Hammer taps precision align the tyre to the spokes(!) The CA is the "cured" with my wifes' hair drier. The cutter head is wound out to 96mm and I use it to score a mark. Then I attack it with the angle grinder, pretty it up on the bench grinder and then turn it to 96mm on the lathe. The CA joints hold the tyre to the spokes firmly enough for turning, (but then this particular adhesive SHOULD do!)
This is where I am at the moment.
(http://www.cabbagepatchrailway.co.uk/neree1pic50.jpg)
I have decided to paint it NER Saxon Green -a colour it never wore...
And Yes, although it will run from batteries it will have functioning pantographs -as have all my G3 electric models. I use "Memory Wire" to raise and springs to lower them. I did "drop test" the design I used on my EF-1 and that has proved capable of taking 6 amperes each quite easily.
regards
ralph
Ralph,
I'm really impressed. I did laugh however at your statement "I am first and foremost NOT an engineer" when you then go on to mention in passing such things as "metal milled away", "four jaw chuck", "titanium threaded bar", "brazed", "CA'ed" ...
Compared with most of us, I suspect you are more of an engineer than you realise.
I look forward to seeing the engine, and even more to seeing the quill drive in action!
Mike
Well I suppose you had better see the rest of the plans for it too then...
(http://www.cabbagepatchrailway.co.uk/neree1pic55.jpg)
Although I think the small preview JPEG is a little on the "squinty" size the
original is full (1:22.6 scale) size. This is as John has surmised the NER no.13
the 2-C0-2 electric locomotive originally designed for the Newcastle to York
electrification scheme. The envisaged design will have three 5 pole motors
each of 223g/m torque rating with a PWAM supply of 10 Amperes at 12 Volts.
As in the original, the leading and trailing bogies will lock , and unlock, when cornering.
The leading bogie was locked at high speed. (Above 50mph). The trailing bogie
was unlocked only when cornering... This of course all changed when the loco
"changed ends". This has required some inspired madness on my part, and the result
is based on 1920's style electromechanics rather than C21st PIC or Stamp systems,
although it was very close!!!
The batteries are located over each of the bogies with the "plates" towards the
centre of the loco to assist traction and C.of.G. I hope to get it completed by
the end of this year.
regards
ralph
Ralph,
A most ambitious project!
I think the place for this is in the Members Only 'Scrapbook' section (where you can have a larger image)with an eventual article for the Newsletter.
One thing is certain (well almost...you cannot be certain of anything these days) and that is, it will share with the prototype, the distinction of being unique amongst G3 models.
There is (or was about 15 years ago) a large scale model on display in a cabinet at the NRM but I suspect that was G1.
John.
Well the steel from "Rob" has arrived and as usual had to cleaned of all the "red chinese chicken dripping" that he insists on using for cutting oil. Much fun was had by father and son playing fit the piece to the plans... I am going to have to change my type of "blue" that I use -normally I scribble over part of the metal with a marker pen and scratch. However this time the "blue" is rubbing off with handling.
Anyway this is what we have for one of the bogies:
(http://www.cabbagepatchrailway.co.uk/neree1pic56.jpg)
I am half way through finishing the last of the 6 driving wheels and the next step will be to cut the 8 bogie wheels. And it the bogie wheels that I am stating to wonder about... In the classical manner they should have the axle fixed between them, however, what I am thinking of doing is fixing the axles and then mounting the wheels on double ball bearings. This "should" give the loco improved cornering ability. I do know that this was tried on the Midland and the NER itself tried something similar. The chief advantage of this is that the fixed axle can be thicker at the slide block in the horn guides and it will not be subject to rotational wear. The main minus point is increased wheel wobble as the bearings wear...
Time to dig out my slide rule and a large mug of tea(!)
regards
ralph
To be honest neither the mug of tea or the slide rule were of any help... What was -was the crabby old english copper plate script of my late fathers notebooks. What I have decided to do, based on the observations and notes there -is to give my loco "Colonial" wheels i.e. no coning and axe edged flanges. They should be easier to machine and steer the loco through the curves, at the expense of "picking" at the frogs or the wing rails -due to the "fat" flange.
My father HATED "Colonial" wheels and Irish wheels and reserved their making for "Friday Afternoons", as it would take all morning to set the machines for the job -and then that left all weekend for the millwrights to get the machines back to "true" again...
My reasons for doing this are more practical then philosophical(!) Although there are several dealers for the "compound slide" that I would need to produce a UK wheel profile on my lathe -none of them will admit to having one in stock. If I don't like the way it corners I can always turn the wheels to the UK profile when I have found someone to sell me a "slide".
regards
ralph
(http://www.cabbagepatchrailway.co.uk/neree1pic60.jpg)
The small image shows the first of the eight bogie wheels about to be cut on my lathe. The 6cm sq 8mm thick "blank" has been drilled out to 8mm and the biggest nut and bolt I could find -"grunted" tight. At the moment I have two of them cut roughly to 5.8cm -the finish size is 5.5cm.
The results from "The Beer Festival Planning Session" are rather good -I am pleased to say, But I would be the first to admit that the constructional drawings now smell of: ale, cheese & onion crisps, and Chicken Tikka Madras... The design of "the spine" that carries the three Quill drives has met with "calculated"(!) approval -although there were some voiced thoughts on: "Perhaps it really should have more roller rather than ball races". The main problem I seem to be facing is getting my Snowflake wheels balanced -otherwise they will want to "hop" in their garland of drive springs and cause unwanted bashing of the tube axle holding the Bull gear!!!
The solution is; either to dynamically balance the Snowflake with drilling and inserting weights -OR (the method I favor) alter the tensions on the drive springs so the wheel doesn't want to move and is forced centrally. The first method requires putting the Snowflake wheel on an axle between two rulers and watching where it wants to "rest" (and then drill a bit of the heavy part of the tyre away). The second entails tightening/loosening parts of the spring compressor until the wheel "floats" centrally. The first method is probably the more correct -but with the second method (although more fiddly) means I can fine tune my Quill drive to the loco.
From the "design" point of view I am just using simple Hookes Law calculations to produce the spring specification that I require. Well in fact the spring rating is the average of the three positions that the spring will be in as it moves in relation to the Bull Gear and the Snowflake wheel i.e. static, driving, and braking.
All this has been made harder by the fact that my son has wiped all the pre-programmed equations from my hand calculator and I am having to do it via spreadsheet...
regards
ralph
Well after a suitable pause due to "End of Year" and "other matters" -I am at last allowed to return to my loco... I have completed the turning of 5 of the 8 blanks required for the bogies, and all went well until the second "session" after last Sunday Lunch. The lathe decided to start up at full revs and refuse to obey the speed control. Then it simply stopped... I have unshipped the board and I am awaiting Chester Tools service dept to get it fixed!!!
During the wait I have been turning my attention to the lights and their connections. The strange red/white dual LEDs have arrived from Texas and I am chopping up lengths of "heat shrink" to make sealed connections with. Once threaded onto the wires they will be greeted by my teenage 25Watt Weller soldering iron -which despite its age is far better than the modern electronic Antex that seems to spend most of its time getting hot....
Tomorrow my friend from "The Welding Institute' is coming around to help me decide how best to begin assembly of my chassis parts. I know that my welding is anything but pretty -but it is strong and I am very good with an angle grinder(!) So, what is the next thing on my shopping list? The answer is the Bull Gears and the spring assemblies. I think that the best way to build the mounts for the Bull gears is to line up all the plates that will hold the Bearings for the Bull Gear and then to "bore out" with my boring bar to 32mm. I then plan to slice the bored plate in two and then weld a hinged clamp fitting to the two halves. This will clamp onto the outer surface of the ball race that supports the Bull Gear.
After some "inspired" madness I have finally decided on the structure of the Bull Gear... This will consist of two Main gears with four 3mm threaded holes through the boss of the gear. This will sit inside a length of 22mm copper heating pipe and then this sits inside a length of 22mm pipe joiner. This gives me an external diameter of 25mm(!) The ball races are then fitted and the other Main Gear fitted and then bolted up tight with 3mm bolts.
The next few evening will be spent painting BSM with "blue" and scribing lines on it!!! I am not too good with a hacksaw and blades seem to break at a great rate...
regards
ralph
Well today and yesterday have been spent wrangling with wires... I hold fast to the saying that any wire cut to exact length is 1cm too short!!! My speed control system (as such) is based on a circuit from the book "Model Railway Electronics" by Roger Amos (I have the 2nd Edition). However I have adapted his "PWayMan Circuit" to my own ends. His circuit uses the 50Hz half wave recitfied DC from the mains as his sine wave to "chop" rather than chopping a square wave -this gives Pulse Width Amplitude Modulation. I on the other hand produce my own sine wave -and thus a variable frequency. What I do is use the same Potentiometer shaft (a double gang) to alter the Mark Space Ratio of the "chop" whilst at the same time increasing the frequency. A little soldering / fiddling with a collection of fixed value resistors in series and I can tune the Mark Space Ratio to the slope of the rise in frequency. Lower frequency =more torque. Higher frequency =better battery life)
What I am about to say now I cannot prove -however I do know it to be valid!!!
For some reason a 5 pole motor is the lowest number of poles that you can successfully use a PWAM system with for smoothness. If you try a 3 pole motor -you would be better to just use a simple supply. If someone could like to come up with the reason -then I would be delighted to know(?)
How my control system works is this: Each motor has its controller capable of 3 Amperes each -fed from a 12 Volt source. They share a common connection to the dual gang potentiometer that alters the MSR and frequency. The change of direction is controlled by a Solid State Relay (apply a ground to pin 7!)
The control interlocks are not even at the "scribbles and doodles" stage -so at this time it would be possible to make the system flip from Full Fwd to Full Rev. What has got to be done is to ensure that the system waits until the frequency of the PWAM drops to Zero -before it starts to ramp it up again.
Time for mental diversion -while the subconcious works it out!!!
regards
ralph
Well after a hard day at the desktop.... I have had to ship my lathe back for repairs -something is wildly amiss and I cannot work out what(!) This has left me nothing to do but sort through my collection of "primitives" to turn into functioning parts of my chassis. So, I looked at them took a deep breath and dived into the two chassis rails. The first thing was to make them "true" to themselves. I wrapped a length of parcel tape around one end and drew a square line with the try square at the other. Deep breath, saw -broke the blade... Thee blades later and I had 4 square ends. The next job is to make a matched pair of them. I duly clamped with my "moles" and marked out two holes and drilled through both pieces. After having grunted two 3mm nuts and bolts through the holes, (this is normally enough to lock the two plates in place), I set out marking up the frame plates for the horns.
(http://www.cabbagepatchrailway.co.uk/neree1pic62.jpg)
I know the preview shot is a little squinty -but you should be able to see the row of 3mm drill holes that form the top of each guide slot. The two holes either side of the central slot are for the 5mm transverse bolts that couple the chassis frame plates to the "spine" holding the motors and Quill drives. The theory is that simply undoing the 4 bolts will allow me to work on the system as it "should" simply drop out.
Always design your model to be easy to do repair work on!!!
regards
ralph
Well at the end of "Fantastic Friday" -I seem to have a pair of chassis frames(?) The shape for the bogie holes was initially made on graph paper and then stuck to a piece of ABS scrap -which was then scissored to shape. I scratched around it and then started my pillar drill work.
Here you can see the scratched curves and the line of 3mm holes.
(http://www.cabbagepatchrailway.co.uk/neree1pic63.jpg)
The curves were removed by the simple method of sawing 4 slots from the edge to the curve and then clamping them in a set of "moles" and snapping them off. The resulting shark tooth edge will be treated to the grinder. Here are the two plates simply held together by a couple of bolts. The plates will be 9cm apart -so they will sit wider than this.
(http://www.cabbagepatchrailway.co.uk/neree1pic64.jpg)
The next pieces to be made are the bogie mounting plates -with the triangular cutouts for the cables and the slots for the traverse of the Bissel Bogie, (and "the mousetrap" that will lock the arm of the Bissel Bogie in position for moving on the straight)....
regards
ralph
Well shortly before retiring to my work with my mug of tea and digestives -I will bring you up to date with the progress. Today I have completed the Bogie mounting plates and you can see them positioned here with the aid of some Blu-Tack....
(http://www.cabbagepatchrailway.co.uk/neree1pic65.jpg)
The next step is to start work on the bogie side plates themselves. Once they are complete I will be able to see if my maths was correct and I have room for them to move side to side without them clashing on the frame plates...
regards
ralph
Well end of another Sunday at the saw... The following shot shows around 95% of the steel work for the loco. This is without a doubt the heaviest thing that I have ever built!!!
(http://www.cabbagepatchrailway.co.uk/neree1pic66.jpg)
You instantly know the models that you cheerfully lug around to "shows and open days" -and those that you don't. This one is one that will rarely leave home. I have calculated an, "all up weight", of 10.3Kg -which is on the border line for one person to "rail" easily(?)
regards
ralph
Domestic (and other) things have meant that there has been little time for me to play in my shed. However at the end of the week I am not displeased with the couple of evening that I have had "free"... In my by-line I write that "Everything I build was real -unfortunately..." and this part of it -is just that. Certain parts of this loco do make sense, some parts of it do not make sense, and some parts of it are simply weird.
This is one of the weird parts.
The part in the picture below I call "The Spine". It functions as the main gearbox and motor base and from this all the drive is transmitted to the wheels. It has a central steel plate with two arms from it. Silver soldered in to the central plate are two M6 greenhouse bolts with two stubs of M6 threaded bar beneath them. Silver soldered into each piece are two M3 bolts which hold the section of 20mm aluminium U section which forms the base of the gearbox.
(http://www.cabbagepatchrailway.co.uk/neree1pic67.jpg)
Turning over The Spine reveals its secret. The Spine is actually a differential articulated joint. Thus during the action of cornering, it moves the central axle across the chassis.
(http://www.cabbagepatchrailway.co.uk/neree1pic68.jpg)
The Spine as actually sat on one of the gears that will form the tubular "bull gear" and you can see one of the 3mm bolts that will be used to transfer power from the gear to the drive wheels via the springs.
But the most important thing that I have done this week is "square" the wheels... During the construction of the snowflake wheel (ie being heated, quenched etc) the wheels have distorted to a slight (but to me) very noticeable amount. So -quite a lot of the evening work has been spent with a "surface" (which I "inherited") and -a hammer... Having got the wheel "suitably persuaded", I then had to re-bore the axle hole in each wheel to "true". This involved putting the wheel onto an 8mm silver steel bar in the 3 jaw chuck of the lathe and gently flicking it round to see what the wobble was. Eventually at the 9mm point I could guarantee a "normal" shaft to my wheel. I now have to sleeve my bores back to 8mm, (I will just sweat in some 9mm K&S brass tube).
The next thing to do is to start building the horns and guides. I favor the "sandwich" technique rather than milling them from a solid block. My axle boxes may be slightly larger than required -but they hold a lot of grease!!!
regards
ralph
I had to try something... I am glad to say that it has worked!!! One of the main problems that I have had is "How DO I fix the wheels to the axles???" The classical method of cutting a slot and ramming a tapered "key" into it only really works when you can "get at" the wheel axle interface... So, armed with my latest toy (I have finally got a compound slide -I have only been waiting 5 months for it....) I cut a 20 Degree taper on the central hub of each wheel. Then having done so I then clamped the wheel in a rotary table and elevated it to 70 Degrees. Now the taper on the hub was parallel to the bench(!) Delicate work with a 1mm then 2.5mm drill in a pillar drill (I broke three 1mm drills...) gave me an inclined hole. This hole I intend to tap to M3 -once I can find/ beg/ steal/ borrow a long Tee tap. All the Bar taps I have will turn the tap ONCE and then the arms clash with the wheel rim...
Anyway, once I have an M3 tapped hole I can then screw in an M3 Allen grub screw -this will crush the brass tube on the inside of the wheel hub and thus grip the axle very firmly.
regards
ralph
Well after several evening of extreme metal dandruff... My late father often said "you have to go into some bad houses before you know you are home" and I always knew exactly what he meant. I have been turning my drivers (I have done all six) and I have started on my bogies (I have done three out of the eight). However this was not done without the development of a complete new dictionary of "words" to explain my exasperation at certain things. One of the things I have are "indexable replacement tip" lathe tools, this means when they go blunt it is a two minute job with a torx driver to turn the tip round and then carry on. And this is what I have been happily doing! But, they are not as "long" as the old tool steel tools... The shot below shows the problem. I had to saw bolts and grind them square in order to get the tool close enough to the wheel to actually cut anything. Then the face plate clashed against the traverse etc etc etc(!)
(http://www.cabbagepatchrailway.co.uk/neree1pic69.jpg))
But in the end things prevailed and I cut my treads and flanges easily. (I don't know whether the threat to take the whole lot out into the garden and smash it to shards with a sledge hammer helped -but it did seem to co-operate after that).
Here is a very fuzzy shot of two completed driver wheels with an M10 nut and bolt for an axle.
(http://www.cabbagepatchrailway.co.uk/neree1pic71.jpg)
Normally my camera work is better than this -blame the diabetic clinic for the fact that I could not focus for several hours after having my retinas photographed!!!
regards
ralph
Another successful afternoon in the shed!!! All the Bogie wheels are now cut, and I have been assembling my horn blocks and guides. I don't use the technique on milling a slot in a block of brass -what I use is normally referred to as "the sandwich method". I have had my mill and lathe less than a year so I am still learning on them. However I can make sandwiches with the best of them.
The sandwich method uses three sheets of brass, two wider sections and a smaller inner section
(http://www.cabbagepatchrailway.co.uk/neref1pic3.jpg)
Torch the ends with some silver solder and it never comes apart...
Once the hornblocks are finished and the semi-decorative axle boxes are fitted to them (they may be made of aluminium channel and platikard -but do hold grease).
regards
ralph
Well now that I am safely back in the UK, and after a family week end at Barrow Hill Roundhouse...
I have begun assembly of the various modules that will lock together to complete the model. I knew right from the start that this was going to be one of those where it "all came together" right at the end -but the end is still some months away! I have cut and made the grease boxes for the bogie axles to run in. These are as I have said simply off cuts of aluminium channel. The bogie axles do not actually rotate the wheels sit on double ball bearings and are thus free to rotate independent of the axle. I am going to have a go at building leaf springs for it, these will probably turn out to be more decorative than functional -so I will "graft" a torsion bar to the back of the axle.
The spine has been test fitted to the chassis rails. This is held in position via four transverse bolts to a "union" (another piece of aluminium channel) which holds the vertical bolts from the spine. The union has ground down square nuts bonded to the sides -while the vertical bolts are held in place by the compression of the lateral threads. There will be a nut and washer providing the final vertical security and "fine tuning" to the position of the spine. Once that is in place it will get pumped full of epoxy putty and thus will give me a rigid mount.
I would have provided you with a few pictures but my camera is not feeling well after having been drowned in Diet Pepsi and TicTacs fountain. My son decided to take a photo that was just a little bit too close....
regards
ralph
I now have one set of bogie axles(!) After suitable persuasion with a "cloth and hide", I had a length of 6mm steel bar that was straight. I duly chopped it up with a hacksaw and squared off the ends in the lathe. These axles do not rotate, but simply act as the carriers for the wheels -which sit in a double ball race.
(http://www.cabbagepatchrailway.co.uk/neree1pic58.jpg)
However turning down the ends to 4mm for the first 10mm each side was good practice for the main event -the driver axles.
regards
ralph
Well now that I have axles with journals on them I suppose I had better explain the process of making a grease box. This is based, (of course!), on Rhodesia Railways practice... I seal up the bottom of the Aluminium channel with some balsa then using a cotton bud mix up up some 2 hour epoxy and swab the entire inside of the thing with it. This gives me a "tanked" seal. Into the chamber thus formed I cut some felt into ribbons and dollop Castrol LM onto it. A small amount of "Milliput" seals the top of the grease box. In the morning after, "a night on the cooker", it is rock hard, and the grease has now been sopped up by the felt. The Milliput can now be ground flat and drilled for the spring mount.
I have drilled and fitted the horn stops for the bogie sides and I now have to fabricate the "leaf springs" that will disguise the coil spring hidden within them. I will admit that I have never been very good at this and on my first G3 loco simply gave up after having broken three in a row trying to make them out of lengths of ABS. This time I will use an L shaped section of brass strip with lengths of brass rod down to the 3mm loop connectors that fix the horn stops in position. The coil spring will sit between that and the top of the grease box and the false leaf spring will sit in front of it.
(This Time -It Is Going To Work)....
regards
ralph
Well the Bank Holiday weekend is here! and in the glorious sprng sunshine -I have spent most of it in the shed... However while the rest of the family were "slipping, slopping and slapping" as the saying goes, I was torching away merrily. I have in the past two days used nearly 3 lengths of silver solder and lost my "cool" in the heat of the forge. The first thing that I set out to solder together was the bogie "saddles" as these are really the most important things in the contruction of the loco (honestly!). The lateral piece of angle iron was duly bolted to the piece of 3mm plate and the torch lit. The main problem with this piece was that the only real way that it wanted to "sit" was upside down. So I clamped it in the vice and cooked it and its companion. Once they had been cooled and pickled, it was out with the wire brush and on to the next stage. This involved soldering square nuts to the corners of the angle iron . So after having polished up the nut and the area of angle iron that it would sit on -it was again out with the torch. I had to use a lower melting point solder for the nuts because if I had used the same temperature as the solder -it would have come apart... At the end of two hours of work I had two saddles that were clean enough to pose for a photo. The saddles are held to the sides of the bogie frames by M6 Allen bolts
(http://www.cabbagepatchrailway.co.uk/neree1pic73.jpg)
The frames were the next victim of the torch... I had planned how I was going to do this some time ago -but as the saying goes "no plan survives first contact with the enemy". I had designed in the slots were the L shaped clamps would bolt through and then G clamps would hold the frame fast to the piece of firebrick. Well after some bench work -I had to move EVERYTHING off my work bench inorder to have enough room for the frames, I did solder the joint. However you can tell where the "nose" of the G cramp was -there is a definate "dab" mark!!! I did bothe ends then hit the next snag. Although the designed in slots had worked well I now had to hold one frame side 9cm in the fresh air while I soldered one end and then the other. This was done by a carefully sawn piece of 3x3 screwed through the slots. and I am very relieved to say that it worked perfectly.
(http://www.cabbagepatchrailway.co.uk/neree1pic74.jpg)
In the previous shot You can see that the two "trays" that hold the batteries and associated electro mechanicals have been bolted on through the slots. The L/H tray contains the power control side of the loco while the R/H has the lights and direction control system. (Note the large relay marked STOP). You may just make out the stub of the bogie arm poking out from the rear of the tray. The arm is fixed at this point and moves across the bogie between the main chassis frames. It is the movement of this arm that will squeeze the Quantumn Tunnelling Composite and thus tell the loco that the front bogie has begun to turn into a curve. This will lower the resistance of the QTC and thus allow enough current through the relay to close it -powering up the solenoid to lift the mousetrap bar.
regards
ralph
I am beginning to hate springs... I had worked out all the Trig and the Hookes Law calculations so the the springs sat perfectly in their stretched length and the forces on them were all correct. Then the manufacturer decides that they are not going to make any more of this value... Thus I have SOME of the springs that I need for the loco -the others I am going to have to scour the web for. Anyway I have enough of the correct value to "float" the bogie arm and bogie (minus wheels) in 3 Space. Thus only the weight of the wheels holds the bogies onto the track -the rest of the weight of the loco is available for traction. The flanges on the bogie wheels will pull the frame across thus transferring some sideways torque to the chassis frames. This SHOULD force the central driver axle away from the centre of the cuve thus angling to two outer axles towards the centre of the curve.
(http://www.cabbagepatchrailway.co.uk/neree1pic75.jpg)
Here you see the bogie arm suspended in 3 Space by the four tensile springs. The mounting point for the connecting point is not central as when the arm moves across in its arc the line between two sets of opposing springs becomes straight and they then provide no real effort anymore. The offset from the "true" is such that the steering effect of the bogie will only be effective in curves of greater radius than 1.50m ( roughly 5 feet).
regards
ralph
Well at last "the postman" has delivered something.... I know the I am on the final push to complete something when I tick off the days for my orders to arrive(!) Anyway, the first installment of gears has arrived with some of the ball races for the gearbox, and all six of the 25mm bore needle rollers for the bull gears. So, I now have three sets of nylon reduction gears in a fetching shade of red -which will have to rubbed down and painted black. The same thing will have to be done to main power gears -except they are white!!!
The next set of gears and bearings are for the bull gear and the bogies.
One of the things I am still unsure of is what to make my gearbox faces out of. I would like to use Aluminium for lightness and ease of machining -but is it too flexible in the thicknesses that I can get it?. Brass would make a lot of the work quite easy, as well as looking nice -but the price is quite high. Steel is dirt cheap -but it would be the hardest to work...
Time for me to get to bed!
regards
ralph
"In the clear bright light of a young morning...." Enough of the lyrics -to work! The shot below shows the arrangement of the gears.
The motor is above (obviously!)
Step one is 20:40 -this clears the side of the motor.
Step two is 10:30 -the 30 gear providing drive to the two 16 tooth gears.
Step thee is 16:100 -the 100 tooth gear is of course the Bull Gear.
(http://www.cabbagepatchrailway.co.uk/neree1pic76.jpg)
regards
ralph
The best thing about enamel is that you can use it in the evening and by morning -it will have set. I normally use Hammerite (in this case Smoothrite!) for my metal work. I am now in the position that all of my chassis components are now painted with two coats -and three where it will take the most hammer...
The shot below shows the chassis with the two bogie side plates and the connecting saddle. The "spine" can be seen bent to its limits, (for illustration), in the centre of the chassis frames.
(http://www.cabbagepatchrailway.co.uk/neree1pic77.jpg)
This is the chassis inverted. Clearly visible is the differential connection to the two arms of the spine. Also visible are the three sections of U channel that will form the mounts for the three gearboxes. The spine transmits the thrust through the two 8mm bolts that it is suspended from to the four 6mm bolts with captive nuts that pass through the two sides of the chassis rails. The bogie axle boxes with their "sandwich" horn blocks are easy to see in this shot.
(http://www.cabbagepatchrailway.co.uk/neree1pic78.jpg)
The bogie sides are sprung and compensate in a manner that would warm the heart of one I.Driver Esq...
The last shot is perhaps the most interesting, (for me). I like for some reason to have my buffer beams made of wood and as normal the buffers are sprung. It was suggested that the draw hook should be sprung as well -so I tried it... I have to admit that I like the effect. My test traction piece, (a tin of nails and a length of string), did seem to want to move more easily with the sprung hook -so I think that this is method that I will employ for this and future locos.
(http://www.cabbagepatchrailway.co.uk/neree1pic79.jpg)
regards
ralph
Well a couple of weeks have passed since the last entry -this has to do with having to tend to my garden... But thanks to severe weather I have been able to spend the odd evening in my shed(!) What I have been slowly building is the "mouse trap" arrangement for the bogies. The patent taken out by Sir Vincent Raven has been applied here -but in a more modest form. The original patent described a longitudinal locking bar that held the rear bogie in place while the front was free to move. This works fine until you have to take the VERY sharp curves that I have...
(http://www.cabbagepatchrailway.co.uk/neree-pic8.jpg)
I modified the patent bar into a mousetrap that held a bar that the bogie swung on. This "amplified" the bogie movement into something that I could electrically "measure".
(http://www.cabbagepatchrailway.co.uk/neree1pic20.jpg)
The Quantumn Tunneling Composite (QTC) varies its resistence between 1.0M Ohms to 50 Ohms at 1Kg pressure. This gives me a 6 Volt Relay fed from a 12 Volt source that would not close until 0.3Kg of force was squeezing the QTC. Whether this would be useful in anyone else's model I have no idea -but you are welcome to use it.
The next shot shows the mouse trap bar closed on the bogie bar (the reed magnet is at end of the bogie bar).
(http://www.cabbagepatchrailway.co.uk/neree1pic80.jpg)
The next shot shows the bar has lifted and the solenoid is the right of the arm -with the return spring on the left side of the arm.
(http://www.cabbagepatchrailway.co.uk/neree1pic81.jpg)
The next step is to wire up the reed that will provide the "earth" connection to the relay. Once the magnet has moved away from the reed the circuit opens, the solenoid drops, and when the bogie arm returns to the straight section of track the mousetrap captures it and the system resets.
(http://www.cabbagepatchrailway.co.uk/neree1pic25.jpg)
regards
ralph
The shot below shows the mousetrap bar and the bogie arm with its magnet CA'ed to it. Above the magnet is the suitably angled reed switch again CA'ed to a off cut of 5mm sq pine the position of the reed is such that it cuts "off" when the bogie arm is 2mm out side of the gap in the mousetrap bar -thus the solenoid holds the bar "up" while it moves across.
(http://www.cabbagepatchrailway.co.uk/neree1pic82.jpg)
Looking at the close up shot -reminds me to touch up the paintwork -when I am finished!!! The next thing on the agenda to build is the QTC cramp -early test systems resembled something out of "The Inquisition" -but I think I am finally on the right track. The early designs had it squeeze only one side -the one I am playing with at the moment is a "U" shaped frame that slides across the eccentric and thus the QTC is squeezed from both sides. This seems to give a more "repeatable" point of deflection than simply squeezing it from one side. This should enable me to accurately position the QTC and compress it so that it can detect curves great than 13 feet radius. This is the curve rate at which the bogies would have to unlock for cornering. Wider than this there would be no requirement.
regards
ralph
Well I have spent most of this morning sawing slices of aluminium U section and sticking squares of QTC to them. The main problem with the QTC is the fact that CA is an insulator... So, what I have had to do is delicately place them on the U section and before CA'ing them into position by dripping it around the edges I put a piece of "hook up wire" between the QTC and the aluminium. This air gap has ensured a good electrical contact(!)
(http://www.cabbagepatchrailway.co.uk/neree1pic83.jpg)
There now needs to be some "delicate calibration" with a pin hammer and a 12 inch vice to make the moving part of the assembly just the right fit for the eccentric...
Once all this is done I then have the problem of getting the body to fit "nicely" over the chassis. I know it does fit -but parts of it have shifted from "true" and will have to be "persuaded" with a mouse sander and a Dremel to meet exactly as required!!!
regards
ralph
I don't know how other people do it -but this is how I do it... Armed with a fresh tin of grey cellulose primer and a large expense of newspaper I rattle my tin for 2 minutes and then start puffing greyness over it. It is actually quite a satisfying experience. All the odd off cuts, bits of black or white ABS, balsa, brass steel washers (and the squadron green putty!) et all all disappear leaving a smooth (hopefully) grey shape. This then "cooks" for an hour under a couple of angle poise lamps armed with 60W heat bulbs. After a couple more coats I am happy.
The fitting session went as well as could be expected armed with my Korashu saw and a Dremel grinder I fettled the fit until it all slid on and off beautifully. I had doubts when I first tried a Korashu saw as I had never seen anything like it -it looks a small dagger with teeth. But after a few trials with it I have found it to be almost indispensable for wood work. They are after all used by Japanese wood workers for fine cuts -it leaves an almost "polished" cut.
This is what the grey primer body looks like fitted to the chassis.
(http://www.cabbagepatchrailway.co.uk/neree1pic84.jpg)
(http://www.cabbagepatchrailway.co.uk/neree1pic85.jpg)
Only one of the pantographs is functioning at the moment due to a "slight accident" by my son... Replacement parts are on order.
regards
ralph
Well it has been a little like Christmas here over the past few days... I now have a complete set of gears for my loco and I have been able to try the one thing that I have waited for for over a year -to make a Bull gear!!! I have had the roller race bearing for over a month and the 22 mm plumbing fittings since the new year. I am very happy and relieved to say that everything has gone together perfectly in the first test assembly. (Honestly!)
The assembly procedure goes like this.
Cut a strip of 0.5 mm ABS sheet 10 mm wide and wrap that around the boss of the 100 tooth gear. Lower the pipe fitting over the abs strip and whack it with a mallet... This ensures a perfect compression fit. Now wrap one layer of PTFE plumbing tape around the 22 mm fitting and slide over the 25 mm internal dia roller race. What you now have is half a tube axle. It moves whizzingly around if given a finger flick -so I don't think that there is that much friction.
The next step is to drill the spider holes in the bull gear and tap them to 3 mm. I know that it would be far simpler and quicker to just drill 3 mm holes and double nut the 3 mm bolts -but it stops the torque of the Quill Drive from undoing one side of the double nut. Knowing Murphy's Law -this will be the side that it is hard to get at!!!
It may be me -but I think this could be the only Quill drive that I ever make...
regards
ralph
Well another wonderfully rainy evening means more play time in the shed!!! The shot below should really be on the entry above -but I ran out of battery power (Lithiums go flat too).
(http://www.cabbagepatchrailway.co.uk/neree1pic86.jpg)
The next two shots show the prototype of the Quill Drive. My version of it anyway... Rather than use Compressive springs I have opted to use Tensile springs. This has several advantages -not least that I do not have to fabricate 72 sets of spring cups... So, there are six tensile springs from the bull gear to the junctions of the tridents. The tensile springs will help stabilize the snowflake wheel.
(http://www.cabbagepatchrailway.co.uk/neree1pic87.jpg)
The snowflake wheel can float vertically +/- 3mm in its tube axle -or swivel +/- 5 degrees.
(http://www.cabbagepatchrailway.co.uk/neree1pic88.jpg)
I wrote above that the spine with its articulated backbone flexibility was "just plain weird" after having played with the home brew Quill Drive -it not only makes perfect sense -it is also vital!!!
regards
ralph
Do you ever ask yourself -"Why do I do it that way?" I have a design habit that I use "Switch to Earth" rather than "Switch to Power". As I have written above I am having the problem that I cannot "get at" the solder tags at the back of the 2 end modules. I now have a tag that has 8 Earth connections to it... I am a firm believer in the principle of "Star Earthing", and as you will have gathered -this is how my model is wired. Normally there are just 3 or 4 connections to the Star point -but I have yet to wire in the PWAM or the lights.
I am nearly at the point where I will have to solder in an Earthing Bar to cope with the amount of connections that will be required...
I am also becoming rather concerned about the amount of waste heat that will be blown around by the motors when running. Granted that the motors have built in fans and I can stick together some ABS sheet to make some ducting from the exhaust ports of the motors -each motor is going to put 36 Watts of heat into my plastic bodied model. The sum heat is about the same as a set of curling tongs...
regards
ralph
Well after another glorious summers day (of rain) and a slight amount of burn creme... I hereby present the world with the wired chassis of my loco!!! Well the control and lights side of it anyway.
(http://www.cabbagepatchrailway.co.uk/neree1pic91.jpg)
The IR "key" that will unlock the power side is yet to be installed (AKA anti small inquisitive fingers device) but the parts for the modulator are in drawer waiting for "iron time".
The next task on the list is to machine up the wheels for the bogies and fit the ball races to them. THEN and only THEN will I be able to test if my maths has worked with respect to the QTC and the unlock/locking of the bogie arms...
regards
ralph
The weekend's work has stopped and I am happy with the progress made -I have a bogie! The shot below shows on the left the painted and sanded wheel with its 2 ball races and one of the collets. On the right is an assembled wheel with its axles (a 6mm dia length of silver steel bar). The whole thing went together quite easily -bar the usual one of sliding the bearings to the right position and using "Green" sleeve retaining compound on them...
(http://www.cabbagepatchrailway.co.uk/neree1pic92.jpg)
The next shot shows the rough assembled bogie on a length of track. You have to give it a push up and down to see how it rolls... I have tried it on my 2 curves, 7.5 feet and 11 feet radius, and it scoots along quite happily. The fact that the wheels are independant of each other means that it can take tighter corners a lot easier than a solid axle. (It also moves as smooth as silk!!!)
(http://www.cabbagepatchrailway.co.uk/neree1pic93.jpg)
The last shot shows the rough assembled bogie in its position under the loco. The damaged finger IS mine -the injury is from passing down my sons skate board from its hook in the hall...
(http://www.cabbagepatchrailway.co.uk/neree1pic94.jpg)
regards
ralph
Well after a suitable break (to do some domestic chores) I have returned to building my loco.
The shot below shows the initial assembly of the spine
(http://www.cabbagepatchrailway.co.uk/neree1pic101.jpg)
The roller bearing sit in wood pillows (made from the remains of my last shipment of rail) and the sequence of assembly (right to left) should be obvious. Hopefully before the weekend is over I should have a rolling assembly!
This is the experimental gearbox...
(http://www.cabbagepatchrailway.co.uk/neree1pic102.jpg)
Yes I will admit to "borrowing" some of my son's Meccanno -but he will get it back. What I have worried about is that fact that the motor may be a little bit too powerful for the loco. It has been tested by laying the output gears across the bull gear and watching the drivers go around. Even at only 6 Volts they are whizzing merrily around...
regards
ralph
I have been very busy, not that you would notice much!!! The spine with its collection of bits has been completed.
(http://www.cabbagepatchrailway.co.uk/neree1pic105.jpg)
Both bogies now have wheels, with sprung axles. The mock leaf spring covers for the coil springs have yet to to be fabricated. The rolling resistance of the chassis on its bogies is unearthly... I can push the chassis along with a feather. The next shot shows the chassis and body "plonked" on top of the spine. The M3 set screws stop the chassis from sitting correctly on the spine -these will be replaced by grubs during final assembly.
(http://www.cabbagepatchrailway.co.uk/neree1pic106.jpg)
regards
ralph
I have traction!!! The shot below shows the "production prototype" gearbox.
(http://www.cabbagepatchrailway.co.uk/neree1pic110.jpg)
Yes, I know it is made from scraps of ABS sheet and balsa, but the point is -that it actually works... I assembled it from my drawings and simply expected to use it to check for "fit" and then "fettle" the gearbox to shape with a pair of kitchen scissors. However since it was just "junk" I had to see what happened when I applied power. If it tore itself to pieces inside a few seconds -then this was expected. It went around and the loco moved -if somewhat slowly. I knew that it was very free moving, but to be totally honest, I would never have expected 20Kg of loco to be propelled at circa 1cm per second by an almost dead AAA NiMH...
So, what it will be like with two fully charged 6Volt SLAs giving it 4.5Ah at 12Volts could be -electrifying(!) There will be two motors powering it, one either end of the spine. The next step is to machine the gearbox out of the 0.6cm polycarb sheet and screw it together. The tension on the bull gear will be maintained by dynamically mounting the gearbox to the same pivot point as the pillow and then forcing it into contact with tensile springs.
This will enable the gearbox to move with the spine as it flexes and shifts when the loco corners.
regards
ralph
Sounds like it's going to be able to pull everything out of the yard, including the tracks!
Well after another Friday in the shed (tomorrow, Sunday and Monday I have been "told" I have to do the Summer House).
The polycarb gearbox!
(http://www.cabbagepatchrailway.co.uk/neree1pic111.jpg)
The sides are CA'ed together and then re-enforced with 3mm setscrews into M3 tapped holes. Polycarb is not hard to work with just completely VILE....
This is the A and B gearboxes placed into position. The central gearbox is still in the aether stage. (Once everything is in position I will know how much space I have got!)
(http://www.cabbagepatchrailway.co.uk/neree1pic113.jpg)
regards
ralph
Well you may ask yourself -so what has he been doing with it -the answer I am afraid to to say -is not a lot!!! Work in my business is seasonal and I have had domestic priorities to deal with -and re-build my wifes summer house...
But while I have not been playing with my locos I have been busy with the speed control system. While doing my researches for the Technical Manual -I stumbled across the american company called "Dimension Engineering". They produce a series of controllers that (quite frankly) were never ever designed to run locos -but they are just perfect for the job. The two that are suitable are the Syren 10 and Syren 25 controllers. They have an on-board CPU and it can be controlled by an external CPU. In the UK they are expensive at £54, when I commented that I liked it, an american collegue commented that; "For $75 it had better be" -then I told him the UK price....
(http://)It operates in a number of "modes" from simple variable resisitor, (great for testing), to a digital serial input, (great for me!).
(http://www.cabbagepatchrailway.co.uk/neree1pic115.jpg)
The device is about 70mm sq (the smaller Syren 10 lacks the big heat sinks).
When everything is finalized I will use a PIC 16 series CPU programmed in the FORTH programming language, (yes I am that type of geek....) But, while I am developing a feeling for what I can do with it I am simply messing about with a BASIC Stamp 2 CPU board. This is a cheap card populated with stuff from e-Bay -I think I spent nearly a fiver on it(?) I think the hardest thing to get was the PP3 battery, (I had to "persuade" my son to let Daddy have the last one from the family stock). The "chip" uses a PIC 16 series with an on board BASIC interpreter -it takes a massive 49 lines of code. (Remember that the Apollo Lunar Lander Computer took 14 lines of code???).
(http://www.cabbagepatchrailway.co.uk/neree1pic116.jpg)
The breadboard on the left is about the size of a floppy, the blue socket is for the BASIC Stamp 2 "chip". Hiding behind the PP3 is most important button in the world -the reset!!! Each of the pins from the "chip" has a blocking resistor for "oops!" events -there are 16 of them.
I admit that I am simply playing at the moment!!! I have it raising the pantographs at startup then whistling three times. When the R/C signals fwds; it whistles twice, the lights then change to the correct code, and then the acc loop ramps it up to speed. The R/C signals slow down it dec loop slows it down, (the inertia is used to re-charge the batteries!), it stops, whistles three times. If the R/C signals reverse the lights change ends, it whistles long once. It whistles twice and then it moves off.
It is all absolutely ridiculous, (and I love it)!!!
regards
ralph
Despite the fact that blood has been constantly pouring everywhere -I have been busy(!) I gashed the end of my ring finger and it has been very messy for the past two days. I finished painting the base coats of Saxony Green and Gloss Black over the body work.
(http://www.cabbagepatchrailway.co.uk/neree1pic117.jpg)
The second pantograph has been repaired after its contact with my sons' Frisbee (don't ask). I have altered the method that I was going to use to hold the pantograph arms aloft. Previously I was going to use my "standard" method of dynamically bending coil springs -but a few high speed tests show that this method is fine for speeds below 1.5m S-1 thereafter it starts skipping.... So. I have gone back to basics and produced a polyharmonic system using three springs. All springs resonate at certain frequencies, thus if you get a spring tensioned to resonate at 5Hz and then tune 2 others to absorb at 5Hz -the result is perfect stability!!!
(http://www.cabbagepatchrailway.co.uk/neree1pic118.jpg)
The last thing to be installed prior to power trials is the Syren25, This is sitting nicely underneath its little cover -where the power resistors would have sat in the original. It too is cooled by a fan drawing air over the fins -as was the original. In fact this little circuit board almost duplicates all the functions of the original system -it also regeneratively brakes the loco.
(http://www.cabbagepatchrailway.co.uk/neree1pic119.jpg)
Everything is progressing well and it is on course to doing a quick trip to the test track (up and down the hall!!!)
regards
ralph
Well you've certainly been busy Ralph - and I suspect the photo doesn't put across the true size of this model. I hope you are going to bring her along to the AGM so we can have a closer look. I'd also be interested in more detail about the control electronics.
Regards,
IanT
IanT,
The Loco is 68cm long over the buffer beams, is 12.5cm wide, (excluding projecting parts!), and weighs in at 15Kg. I do intend to bring it to the AGM -but some thought will have to be given to the carrying cradle. This is simply two 1m lengths of steel angle on 2x1 sleepers. It is fine for humping it from one side of the kitchen to the other and maybe the shed. But, I cannot see it sitting well in the luggage rack of a Cross Country Voyager en route to M/K...
As to the control electronics -they are ridiculously simple. The Basic Stamp 2 chip has 1 serial input (PIN 2) and 1 serial output line (PIN 1), PIN 5 to PIN 20 are the general i/o lines. The Syren digital input is connected to the PIN 5 of the Basic Stamp chip. The main problem I now have is -where do I put it???? Despite the size of the loco there really is very little room in there, and I am beginning to debate whether I can get a place far enough away from all the power electronics to provide a nice noise free location -the alternative is to erect a Faraday cage...
regards
ralph
Now the serious work begins and the "fun" part is over...
I have The Syren 25 ESC, The Basic Stamp 2, and (finally) The Giant Cod 2.4 Ghz 6 channel R/C unit. Now the main parts have to grafted together and got to function as a whole. The Cod controller seems to be a re-use of classical RF modem equipment and there was some domestic concerns as to what frequency it operated on however non of the domestic equipment has complained... The Rx for the Cod equipment did prove "interesting" to set -but this is not their fault. The Rx is housed in a translucent smoked plastic box the main problem being that the cable indicators; (signal) (+) (-) are cast into the moulding and very hard to read!!! A slight rub with a chinagraph pencil revealed the legends though.
After having wired the plugs for the connection coupled up a battery pack to the Rx -I began.
I personally like to have separate battery supply for a Rx, it is a personal foible based on the noise from the BE connection on most ESC units, which I find to be excessive compared to a pure DC supply. Pushing in the 8 AA batteries to the Tx produced, (after some terminal cleaning), a red light. Step one complete. Turning the power on to the Rx produced -nothing... A quick check of the connections and try again(!) Pushing a (loaned) quilting pin into the central hole at the rear of the Rx unit produced the green light on the Rx unit. This showed "binding" to the Tx unit was established. Step two complete. The next steps involved plugging in servo and wiggling the sticks to find which socket -was which.
A few minutes produced the following "cheat sheet".
Ch 1 l/r on RHS joystick.
Ch 2 u/d on RHS joystick
Ch 3 u/d on LHS joystick
Ch 4 l/r on LHS joystick
Ch 5 (?)
Ch 6 (?)
Ch 7 -is actually the Battery input line(!)
So, the next step is start assembling the digital cable work to make everything happen. I think that I will start off with simple 3 core twisted cable at 2 twists per centimetre -which should "knock out" the 32Khz hum from the ESC. Then I have to isolate the motors from each other, the supply lines and then star earth the shielding to them.
In short -all very boring slog....
regards
ralph
Sorry -I forgot to post the pictures....
(http://www.cabbagepatchrailway.co.uk/neree1pic120.jpg)
This shows the Rx unit plugged into the battery with the on/off switch.
(http://www.cabbagepatchrailway.co.uk/neree1pic121.jpg)
This is the Tx unit.
The next shot shows the initial test lash up. The bright blue LED on the ESC looks like continuous arcing in the roof top hat fitting. This is quite unnerving in a wood and plastic model(!) The ariel from the Rx unit has been placed under the unshielded test motor to try and induce maximum interference with the signal -as yet I have been unable to induce any.... But, I will slog through the wiring procedure, just in case.
(http://www.cabbagepatchrailway.co.uk/neree1pic122.jpg)
The twisted strands of the signal lead are plugged into Ch 3 -which is the click stop Left joystick. A little playing with the trim control was needed to get exact neutral position. The setting that the ESC is currently using is R/C standard in mode 1. The digital (white) cable is connected to S1 on the board and the (-) and (+) lines coupled to the Tx unit. This involves putting DIP 1 DOWN and DIP 2 UP. There are8 DIPS, 4 types of setting and 17 modes for this ESC...
Am I happy -yes definately!!!
regards
ralph
At the end of a very successful Sunday morning in the kitchen. I have completed the first static tests of my loco Having perched the loco on the ends of two drawers I then began to plug up the fuses in their racks and and the "yank" cable that you pull to kill everything dead. The 6 volt SLA bricks had spent most of the night being charged and I thought I was now ready...
I rigged up a impact zone at either end and connected the battery.
Thankfully nothing happened!!!
Clicking the joystick on the Tx one notch up, produced grumblings from the motors, at two notches they were turning.
(http://www.cabbagepatchrailway.co.uk/neree1pic124.jpg)
What I like about this is that the "notching" is very noticeable, and it duplicates the actual method of working. The model will have 14 notches and the real loco had 12. The shot is the best I can get -sorry! I had hoped to get a nice picture with all the wheels and cogs blurred by motion -but the camera is too smart for that....
Now that I know that the system is actually going to perform as expected, I can sit down and work out the suspension -which is going to use wedge shaped strips of sponge rubber. This has the advantage that it naturally damps itself and the stresses are all linear. The rubber that I intend to use is used as the packing material for hard disc drives. Its properties are well documented by the manufacturer concerned and I have a ready to hand supply of used packing pieces...
regards
ralph
The evenings test on the kitchen floor test track have proved that I REALLY do have to sort out the suspension... I didn't mind the wheel slip, that was expected, but rather the wheels hopping and bopping to the quill drive as it tried to centre the wheel. What I intend to do is drill each of the sandwiches and install a U top bar. Into this I squish my shaped rubber strip. This then rests against an L frame which hides "the multitude of sins" that is the suspension(!)
A few 2.5mm holes, a few 3mm taps and I reckon I will have something that will work.
regards
ralph
I have sat down and designed my suspension system, this will be made from 7mm L shaped sections of brass and 6mm sq sections of brass -all from the local B&Q. Because the sandwichs slide fore and aft while cornering, there has to be a gap between the guide and the sandwich -in this case 5mm. The L sections will be silver soldered together and then "prettified" with by chopping the corners off and rounding them to give a more pleasing design. The re-enforcing angles will be made from offcuts of ABS strip and stuck on when everything is ready
The next step will be to design a drilling jig to produce the pilot holes (2.5mm) for the M3 tap -then the 3mm threaded studs can be "Loctited" into place on the chassis rails.
The more I look at the motors, the more I feel that building a plenum chamber, and ducting the air from the overhead fans directly to the front of the motors -is a good idea. This will also entail building some ducting to direct the exhausted air from the motors to the outside...
It looks like a busy Sunday in the kitchen(!)
regards
ralph
Making the horn guides has begun. After the wait for the supplier to get the correct grade of silver solder into stock, (I like J&M Silver Flo55), the building of the "jigs" can begin. These are normally made from off cuts and scraps of balsa and today was no exception. These have been knocked together from 5mm sq pine strip. It is also the first time I have used yellow "Aliphatic" glue -which I am not quite sure that I like...
Here you can see the brass "L" sections on their jig.
(http://www.cabbagepatchrailway.co.uk/neree1pic125.jpg)
The sections are then "CA'ed" to the back of a sacrificial piece of balsa this gives a rigid structure that just has to last long enough in the MAPP gas flame to get the solder to flow along the joint!!! The piece is separated from its jig by some delicate work with two forks...
(http://www.cabbagepatchrailway.co.uk/neree1pic126.jpg)
The next step is to assemble a suitable holding device, (probably a small vice), to hold the pieces in place while I hit it with the torch.
regards
ralph
Sorry for the delay in getting back to this -but you know how it is...
The pieces of balsa with their L sections of brass strip (a B&Q special) have been used to produce the second of the series of three jigs. This is the one used to align the hornguide for drilling the holes for the chassis side rails. Some polite work with CA produces the jig and this was clamped to the bed of the mill.
(http://www.cabbagepatchrailway.co.uk/neree1pic127.jpg)
The procedure is simple -drop the piece in drill the hole and repeat until there are no more pieces, move the drill, etc, etc. This means that although the holes may have a slight offset from square -they ALL have this(!)
The now drilled hornguide, still stuck to its piece of balsa, is then in turn stuck to a piece of scrap steel.
(http://www.cabbagepatchrailway.co.uk/neree1pic128.jpg)
This piece actually was used to produce the tridents for the fabrication of the snowflake wheels. The holes from the hornguide are drilled through. After some tapping to M3 NOW there is a master jig that can be used to produce the hornguides from...
(http://www.cabbagepatchrailway.co.uk/neree1pic129.jpg)
The last shot shows the reverse of the master jig. The pieces to make the hornguide can be "nutted up" to produce a nice square edge before the torch. The area where the solder will "spit" onto the steel has been well scrubbed with a pencil. Next Step is: Silver Solder, Borax and MAPP gas!!!
regards
ralph
After a few scorched nuts and bolts, I have completed the silver soldering of the hornguides. These then got suitably trimmed and filed to shape before meeting the red-oxide primer.... The next shot shows the hornguides bolted to the loco chassis. I am beginning to develop a deep dark hatred of doing things 6 times over....
(http://www.cabbagepatchrailway.co.uk/neree1pic130.jpg)
As you can see the paintwork is beginning to arise out of the paint pots(!) There never was any "official" paint work for this loco as it spent most of its time in either Grey Primer or whatever the apprentices at Doncaster had to experiment with at the time in the paint shop.
regards
ralph