5" gauge model of 4472 Flying Scotsman

[Atlantic 3279]

Marvellous! Nothing more need be said.

[S.A.C. Martin]

Beautiful work. Lovely stuff.

[Mersey508138]

I completely agree, I watched 1 of the videos posted on rmweb and the level of detail described is absolutely top rate work.

If the same videos are posted on this forum, I recommend that anybody who hasn't watched them yet please take a look at them and you'll see what I mean.

[greenglade]

thanks for the kind words guys and thanks Mersey508138 for the reference to my video's..I'll put my hand up and say I lose track of where I post some things, especially when they aren't embedded and easily visible.

Here's the links to the two recent walk-around video's, there are many more on my blog page 4472flyingscotsman.co.uk

https://youtu.be/vI9MIqHN4co

https://youtu.be/_yR-k0WVUFc

Kind regards

Pete

[Mersey508138]

Anytime

[greenglade]

Evening all.. I've decided that my next task is to set the chassis up as well as I can at this stage in the build, there will be a fair bit more weight added but it shouldn't involve too much work in adjusting the springs to suit. Going by the current weighbridge results I have a fair amount of playing around to get the chassis balanced.
Why do this now I hear? simple, during transit on Saturday I broke a top leaf spring on the left-hand side trailing axle. All my own fault, I had tightened the spring hangers to the max to bring the weight down at the rear for when fitting the pistons/rods so that I could roll the chassis without needing to push down hard on the rear to get the chassis level, what I forgot to do was loosen the springs when the boiler was fitted and thus putting them under a lot of stress, with zero movement left in the spring during transit it was inevitable that hitting the first pothole would not end well. Some may recall that I have slowly been replacing steel for Tufnol on the rear Cartazzi springs as the weight increased and I had a better idea of how much springing I need. Going back even further into the build when the springs were first made, it took over 100lb to get the springs to sit at their ride height, clearly, the springs were far too strong but I left for the reason above.

So with all the weight greatly increased and suffering a broken spring ( only took an hour to make a new one and it could be fitted without removing anything else) it is time to get the chassis close to balanced and going by the results today, it has a long way to go.
This picture is weighbridge MK2, nothing wrong with the first except for me leaving it outside in the rain resulting in the screen no longer working, I could still see the weight via Bluetooth but wanted the screen to be working too. I have made better use of the original casing this time around but the basic design is the same as before.

I have made better rising plates which now have a machined recess so that they locate better on the weighing plate, as with before, with two plates fitted this weighs the axle, remove one plate to weigh the opposite wheel to it alone.





I have the prototype's axle weights from one of my reference books which I then scaled against the model's total weight against the known axle % rates

Prototype weights are engine 92 tons
Front bogie 17 ton
Leading driver 20 tons
main driver 20 tons
rear driver 20 tons
trailing axle 15 tons

percentage split, 18.5%, 21.7%, 21.7%, 21.7% and 16.3% respectively

using the above percentage splits and a little maths I can get a ballpark figure for the model

model weight (currently) is total of 231.4 lbs (more than I had thought, this makes the boiler alone over 90lbs empty, IIRC the volume is 9 Ltrs full, so nearly 20 lbs with perhaps 15-16 lbs running weight)
Front bogie leading-axle 33.8 lbs
Front bogie trailing axle 35.8 lbs
leading driver 20.8 lbs
main driver 27.8 lbs
rear driver 69.4 lbs
trailing axle 43.8 lbs


What I need to find with the current total weight approx is
front bogie (total weight) 42.8 lbs
leading driver 46.28 lbs
main driver 46.28 lbs
rear driver 46.28 lbs
Trailing axle 37.71 lbs

So I have a bit of work ahead of me in adjusting the spring rates to get them closer to those above.

At least when looking at the current axle weights and noting how tail heavy the loco currently is I can understand why the trailing axle spring failed when it had been left badly adjusted at full deflection, it's not surprising that the top leaf snapped on one side. I should also add that my son's van is lowered with large alloy wheels and the side nearest the loco's broken spring has its own suspension issues with a damaged spring resulting in it sitting lower that side. Something that I wasn't aware of at the time of loading and had secured the loco down on that side as it was the opposite side to the driver and thus trying to equal the weight and also following good practice and not sit with a heavy weight behind me.

This info isn't on the blog, two reasons, one where the server is located is having some maintenance by Virgin and thus it's down and two I have been asked to do an article covering the weighbridge for the mag which will be in much more detail and will hopefully include the final measurements and pictures of the weighbridge construction.

Hope this is of interest, it's very much early days and the final figures will change. The current weight shows that the model is certainly going to weigh a fair bit more than Don's design, at 231 lb now ( design weight with tender is listed at 230lb), and with still a lot more parts to be added she's not going to be light. All those extra details and the modified boiler will see to this for sure..

Pete

[greenglade]

good day all, last time I posted I said that I was going to spend some time weighing the axles to get the model close to the prototype percentage-wise as a baseline. I haven't finished yet but am getting close with mainly the rear and main driving axles needing attention. Once those are closer I'll then measure each wheel independently to get the axles balanced on each side. I have filmed another video showing the weighbridge in action, if you compare the last readings with the targets given in my last post, I hope you can see that I'm going in the right direction.

https://youtu.be/1SLc_vPv5Xo

Pete

[nzpaul]

Despite that being something most of us are unlikely to use, that's really interesting stuff. Just one question, which wheel did you jam your thumb under to turn it black like that?

Paul

[greenglade]

Despite that being something most of us are unlikely to use, that's really interesting stuff. Just one question, which wheel did you jam your thumb under to turn it black like that?

Paul

thanks, Paul.. alas that is an unknown....I don't recall catching it, something my doc seemed a little worried about... I just keep plodding on...

[greenglade]

Today I have played around with balancing the chassis and have to say that I am very happy with how this has worked out. The model is now getting pretty close to the correct scaled percentage weights for each axle. I could take it further, perhaps even getting it spot on but see no need as the weight will continue to change and grow by a fair amount before the model is complete. I'll do the final tweaks when finished, the important thing is that the weighbridge and adjustments to the springs have proved themselves very able to hit the required targets when that time comes. I have given full details in the blog, hope it's of interest...



http://4472flyingscotsman.co.uk/locomotive-weighbridge/

Pete

[greenglade]

Evening chaps/chapesses

Tonight I cover the making of the combination levers, I am beginning to run out of motion parts to make although those few parts that are left won't be a five-minute job to machine, however, I am getting closer to that all-important milestone of running on air, assuming she will actually run that is?... It will probably be the union link next plus all the required pins but I have some things to do first in preparation for making the ashpan which means the boiler needs to be removed. This is no bad thing as it needs to come off anyway so that I can remove the running boards to fit the now finished combination levers.... it seems that there is no end to how many times the model needs to be taken apart...



http://4472flyingscotsman.co.uk/combination-lever/

Pete

[burnie]

There's a lot of engineering goes into building this loco, superb work Pete

[greenglade]

There's a lot of engineering goes into building this loco, superb work Pete

Thanks, burnie... there sure is a lot of work in these things. frightening still is I haven't really started on the more involved bits such as steam valves, pressure gauges, and injectors yet..... I suspect they will take longer than their size might suggest...still, I'm getting there, combinations levers are now finished... they just needed rounding off around the oil pots and of course, make the oil pots themselves and fit them. Today I have also finished the brass trim around the splashers, these have now been sanded smooth with various grades of W&D and polished using Autoglym, finally, they were glued to their corresponding splashers with epoxy. I have also test fitted a template for the top of the ashpan that fits against the foundation ring, all good and hopefully the ashpan will be fabricated by Xmas, we shall see...

kind regards

Pete

[greenglade]

Not a blog entry as it's only a catch-up, just finishing up parts touched on before. In this case, it's those unique pieces of brass trim that are only found around 4472's splashers in the class. Two pictures, one to show one of the trims after being polished using Autosole, it's difficult to photo how shiny it is, trust me it's pretty bright. The other to show the trim now fitted to their respective splashers, these are bonded using an epoxy. Later in a few month's time, I'll tackle the black/white lining once the green has fully cured.





Pete

[greenglade]

Evening all, tonight I have the union links, these have taken much longer than they should have, purely as I had to wait 10 days for a suitable woodruff cutter, the first company failed, sending me an email a few days after ordering to say they were out of stock and not expecting any new for 4 -6 weeks?? The next company I heard nothing from, contacted them yesterday, promised to call back, and didn't but did send a confirmation email of the order? The cutter arrived this morning so good on them for realising they had clearly forgotten my order and swallowing the cost to send it out next day delivery. So that's my excuse and I'm sticking to it...

here's the link



http://4472flyingscotsman.co.uk/union-links/

Pete