NER EE-1

[cabbage]

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

[cabbage]

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

[cabbage]

Sorry -I forgot to post the pictures....



This shows the Rx unit plugged into the battery with the on/off switch.



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.



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

[cabbage]

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.



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

[cabbage]

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

[cabbage]

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

[cabbage]

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.



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...



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

[cabbage]

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.



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.



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...



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

[cabbage]

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....



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