1/32 TME King Arthur

Discussion in 'G1/32' started by taliesin, 26 May 2014.

  1. David Halfpenny

    David Halfpenny Western Thunderer

    A dab of chlorine bleach gives a dead flat black on silver. [Kitchen accident . . . :-( ]
    David
     
  2. warren haywood

    warren haywood Western Thunderer

    These are fantastic models, I may be wrongbut shouldn't the Malachite livery be lined black and yellow
     
  3. Thirtysecond

    Thirtysecond Western Thunderer

    s-l1600.jpg 6281626656_7c23a7131d_b.jpg

    We only have one order for a loco in malachite green out of the 25 being built and that has been asked for as 841, preserved as "Greene King" in the 1970s. Greene King Breweries of Bury St Edmunds sponsored the loco in return for the name. Good PR I guess!

    So it is not in the Bulleid livery of the late thirties/forties, which you rightly point out should include yellow lining, but is in that applied to Greene King in preservation. References clearly show Greene King with white/black lining at that time, possibly applied in error or because that is how Greene King Brewery wanted it. Who knows?

    Aesthetically, I prefer the yellow lining with the brighter green livery but unfortunately that's not how it was in the period in question....
     
    Last edited: 14 April 2017
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  4. stuart hithersay

    stuart hithersay Active Member

    Hi Derek any more news? I am going to Doncaster tomorrow is Chris or yourself going to be there?

    Regards

    Stuart
     
  5. Thirtysecond

    Thirtysecond Western Thunderer

    'Fraid not. But today I finished all the 25 tenders. Much more work in them than you would think.

    Here are three of them in close up.


    IMG_2125.JPG IMG_2127.JPG IMG_2132.JPG and here are 23 of them!! Next week I will helping Chris start on the steam tests.

    IMG_2133.JPG
     
    Last edited: 11 May 2017
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  6. stuart hithersay

    stuart hithersay Active Member

    Simply amazing Derek! Can't wait to see the real thing when it arrives! These are going to be some of the finest gauge 1 locos ever produced!

    Stuart
     
  7. Peter Insole

    Peter Insole Western Thunderer

    May I take the liberty of correcting you Stuart?

    Please delete the words: "some of" from your reply!!!

    Pete.
     
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  8. stuart hithersay

    stuart hithersay Active Member

    They are going to be beautiful and unlike anything else available Pete but there are many fine locos out there. Today I've seen a 4 cylinder gas fired Princess Royal scratch built that was stunning!
     
  9. Thirtysecond

    Thirtysecond Western Thunderer

    It is comparatively easy to build a model locomotive which is externally accurate and well engineered . Question is, did the Princess Royal have a completely scale cab interior with working controls (also scale)? Did it have cylinder drains that operate from a prototypically correct and scale lever in the cab? Were the oversize working pressure and water gauges hidden from view. Etc, etc. Unless the answer is yes I believe Pete is right. This is where TMEs models are so unique and what sets them apart.

    Chris will be semi retiring after this batch and i can't see anything of this quality in gauge one live steam ever being built on a commercial basis again. Those lucky enough to be on this order batch will possess the finest Gauge One live steam models ever built in my humble opinion.

    (Derek -TME customer as well as TME "apprentice".)
     
    Last edited: 13 May 2017
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  10. adrian

    adrian Flying Squad

    Absolutely stunning modelling and inspirational.

    I've only just spotted however this reference to water height LEDs and associated electronics. I'm curious as to how this works, my Dad used to have a couple of 7mm coal fired locos and in this scale the water gauge was next to useless. Fine when cold but when running it could say full or empty irrespective of the actual water level in the boiler. Are there some sort of sensors fitted in the boiler at different heights and are they home-brew electronics or is it a commercial system?
     
  11. Thirtysecond

    Thirtysecond Western Thunderer

    There are two resistance measuring probes positioned one at the critical low water point and the other at the level at which steam space reduces to a minimum for good running (just before priming). A logic circuit then does some simple Boolean algebra.

    Lower probe not activated AND high probe not activated = RED LED- "Low water level, do something quick!"

    Lower probe activated AND high probe activated = WHITE LED- "Danger of priming, turn off by-pass"

    Lower probe activated AND high probe not activated = NO LEDS lit - "Water level good."

    The electronics were bought in but I can't remember the supplier. Chris made the probes in-house.
     
    Last edited: 13 May 2017
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  12. jamiepage

    jamiepage Western Thunderer

    Some water height LED systems are available off the shelf.
    This set up came via Just The Ticket and is destined for my G3 0-4-4T

    The first para describes operation of this one. Like a simple try cock really, water level is either above or below the probe. No gradation.

    IMG_0008.JPG
    The probe screws into 1/4 x 40 bush on the boiler.
     
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  13. Peter

    Peter Western Thunderer

    Hi,

    The brains behind this idea is given to Roy Amsbury who had an article with circuit drawing in Model Engineer number 3494, 2 August 1974.

    Peter McCabe followed on from this article in the G1MRA Newsletter 197 Spring 2003.

    There have been subsequent articles but I do not have them to hand at this time.

    Peter
     
    Last edited: 13 May 2017
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  14. Peter

    Peter Western Thunderer

    Hi,

    If using this system, I would be concerned that NO LEDS lit would also mean, circuit failure, LED failure, Battery failure.

    Peter
     
  15. adrian

    adrian Flying Squad

    Thanks for the info - the probes look quite simple to make just a brass screw in an insulated bush, although still need careful design to handle the pressure of the boiler.
     
  16. Thirtysecond

    Thirtysecond Western Thunderer

    The alternative is to have a bright LED shining all the time while you are running normally. Might be acceptable in most gauge one locos but would detract from the realistic cab that Chris is trying to create. It would be difficult to hide and would certainly show under the fireman's seat where we have it.

    You test the battery, probes and circuit on the King Arthurs as part of the prep. before a run. Once up to pressure on the blower you would continue to fill the boiler until the "full" LED comes on. This can only happen if both probes are operational, the logic is working and one at least of the LEDs is OK. I think it acceptable to assume that both the LEDS are 100% reliable.
     
    Last edited: 13 May 2017
  17. Steph Dale

    Steph Dale Western Thunderer

    I don't think it is fair to assume the LEDs (or any other part of the circuit for that matter) are reliable.

    But, I think it is fair that the filling and testing routine provides enough confidence that the system is working at the beginning of each run.

    Semantics? Probably. Reason to assume the system is adequate and, from a safety perspective, the risk is As Low As Reasonably Practicable? Absolutely.

    For the record, I think they're lovely models too, and I'd hate the thought that anyone would be worried about running one from a safety perspective.

    Steph
     
    adrian likes this.
  18. Thirtysecond

    Thirtysecond Western Thunderer

    In an ideal world any electronic boiler level system would self test on switch on, signalling success by flashes on each LED. But even this has limitations. It would only test the probes in one initial state.

    Any system can fail even given indications that all is well. In critical systems (nuclear, real railways etc) there are multiple sensors that "vote", sensor check circuits and check circuits that monitor the check circuits . But complex monitoring systems introduce reliability problems of their own and in any case would be ridiculous overkill in our situation.

    Even in the alternative "LED always on" system suggested, there has to be an assumption that the probe is functioning normally. Theoretically it could fail "on" and give a counter indication that all was well when it wasn't.

    So given that perpetual illumination of the cab in LED light is not an option for us, the pre-flight check is definitely the way to go. Personally I drain my boilers after every run so having the boiler level system on from initial fill from empty through to overfill will test check that the two probes are detecting water or the absence of it , that the logic is operating, that both LEDS are working and the battery has charge.

    Were these gas fired locos then the risk assessment would be different. A dry boiler and gas firing could cause expensive damage. But the bottom line of Meths firing is that once there is no steam to draw the fire, it will not do any damage to the boiler. There isn't enough heat. I always have a CO2 gas cycle pump to hand in my pocket which will extinguish a Meths flame instantly in an emergency preventing any damage to paintwork.
     
    Last edited: 14 May 2017
  19. Martin Shaw

    Martin Shaw Western Thunderer

    May I ask, is there a water gauge as such, or are you wholly dependent on the electronics working? You may appreciate I'm coming at this from a full size perspective where there are two independent means of establishing boiler water level, and it is not wholly fair to make a direct comparison. But none the less, even at this size if it went bang, it would be messy. Notwithstanding all this, lovely models.
    Regards
    Martin
     
  20. Thirtysecond

    Thirtysecond Western Thunderer

    Am I not right in saying that most GWR locomotives typically had only ONE water gauge?

    There is no room on these models for a traditional water gauge. The uniqueness of TME models has always been highly detailed scale cabs and the electronic water gauge is all there is room for. To put things in perspective I have two gauge one live steam models with no means of determining water level at all! I have no problem with either; experience tells me exactly when to add water.

    You really can't compare a gauge one model to a real one in safety terms. Ours operate at 50ppi. yours at 150 plus. Ours are powered by a simple Meths flame, easily extinguished, yours by a huge bed of white hot coal. I could stand corrected but I cannot recall one explosion, or even failure, of a Meths fired boiler in my 40 years of gauge one live steam.
     
    Last edited: 14 May 2017