5" gauge model of 4472 Flying Scotsman

[greenglade]

Ejectors are nearly finished, a little more fettling required. A picture to show them and their sandpipes connected to their respective sandboxes. The next job is to fit the boxes to the frames, adjust the pipework to its correct position and make the brackets that support the ejectors to their sandbox.



Pete

[greenglade]

Slight change in plan... after sharing my progress on FB it was kindly pointed out that the ejectors that I had copied are air ejectors from an 08 shunter, I had assumed 4472 was still using steam and thus thought it safe to copy them... live and learn as they say... still, nothing that couldn't be corrected, a full days work mind you....I now have steam ejectors following the famous close up of the driver and fireman from the 1934 100mph run. I guess that I should have looked closer at these before...lol

Anyway, here's the steam ejector, it's close enough using the part already made and after adding an extension for the steam feed.



I have also tested the amount of vacuum drawn.. approx 7 inHG at 60-65 PSI.. I couldn't go any higher as it blew the pipes off and I was using both hands to operate and film.

https://i.imgur.com/LiIPz2t.mp4

Pete

[greenglade]

A short video showing the first test of the steam sanders using compressed air,... I have placed a sheet of W&D under the wheel in an attempt to show the sand better, it's very faint in colour and thus difficult to see exiting the nozzle...

https://i.imgur.com/7xyOJ6U.mp4

next job is to make the operating gear for the gravity sanders...

Cheers

Pete

[greenglade]

Morning all...

The steam sanders are now fitted to the loco and we now have the first run of copper pipework between the frames, this area will be covered with pipes of various sizes once the model is completed... alas, I still have a long way to go before that day arrives but arrive it will..



Cheers

Pete

[greenglade]

A present from my youngest son, he did these etchings for me at work. The large builder's plate is for when the model is on display at an exhibition etc, the other is a spare. The two smaller plates are to be secreted on the model somewhere for security reasons. The tiny brass plates are for the reverser dial marker plate that eventually will be fixed to the backhead cladding. I did the drawing for these, scaled from some photo's that I took when the loco was in the NRM in 2016, one of those pre-arranged early morning photo sessions. I have some machining to do on these, the slot or course, which you can see has been etched. I'll also need to machine the wider recess on the back for the marker to travel in to show what cutoff is in place and I'll also remove a small amount around the edge for it to sit within the backhead cladding sheet. He made a great job of these for which I'm very grateful, he has also etched the diamond grid in the loco/tender fall plate which also has my name etched in the middle but accidentally left this part at work, hopefully, I'll have it in the new year.



Merry Xmas everyone...

Pete

[greenglade]

Both gravity sanders have now been built with their associated valve gear within, just need to make up the control arms and linkages. For now, I'll only do the rod that connects the two together for testing, some paint and that will be them for now, I'll post a link to the testing once completed. The picture gives an idea of both gravity and steam sander positions, the pipework will be tweaked into their final positions once the model is sitting back on rails.



Cheers

Pete

[greenglade]

here's the video link to show one of the gravity sanders in operation... I saw no need to test both... onward and upwards...

https://i.imgur.com/qFdJ55Z.mp4

Pete

[greenglade]

It's getting a bit crowded around the gravity sandboxes... you can just about see one now permanently fitted in this picture, once the rest of the motion is fitted it will be more or less invisible...lol



Pete

[greenglade]

I'm now making a start on the draincock mech...i'm doing this now as they are operated via 'Bowden' cable which needs to run as straight as possible, so best get it done before there's too many lengths of copper pipe getting in the way. This is the main shaft that sits under the middle cylinder, you can see where the pulley for the cable, there's another identical pulley to put in the cab. Hopefully, I'll get the bowden cable and their copper outer tubes fitted this week. I may leave the draincocks until later, although it might be prudent to fit those for the middle cylinder... I just need to find photo's of LNER draincocks and drawings is possible... some more research ahead...



Pete

[drmditch]

Re: Use of Bowden Cable

I'm not quite sure what date your model is reflecting.
I did launch a discussion on the use of Bowden cable on the big Doncaster engines ....here....

My understanding is that this started with the A4s, but then was gradually re-engineered into the older designs.
It must have been a lot easier to fit and maintain then rod/lever/crank linkages.

[john coffin]

I would guess the biggest problem with the Bowden cable is building in a simple adjustment mechanism
and making sure that the cable can be replaced easily. Anyone who rode an old British Motorcycle knows
the problems with that, especially the tight curves.

Looks really good though Peter.

At MEE last week, apart from watching Tim of this parish making his cab fittings I was blown away by
the large scale tender for an American BIG BOY, you could party in the thing.

Paul

[greenglade]

Thanks for the link to the discussion on Bowden cables drmditch, in particular, Eddie's note on 4472 regarding the access oval being there in 1935, I guess that covers me then as I'm building her as in 1938. I've just had a look through Yeadon's and can see what Eddie is referring too... it's not very clear in that particular image but there are some others that show the same oval (slanted forwards) cutout which is middle of the two upper washout plugs and at the same distance on each loco below them. Thank you for the heads up on this, I'll try to remember to include it in the cleading when I get there.


Thanks, John...the plan is to feed the cable's in from the front, at this end, the cables will have a permanent ferrule attached and then pulled tight in to the cab. A further ferrule will be attached at this end but only crimped, not soldered. I'll leave a very small amount of cable overhang so that if required I can remove the ferrules and re-crimp new ones in a different place to adjust. I have planned ahead with this and ordered slightly larger ID copper tubing than required, only 0.4mm larger but it should help in two ways. First, I'll be able to get the lubricant in easier and more of it and second, it will help the cable pull through any stubborn corners. I think the most problematic being where it goes around the firebox.

Hopefully, I'll have a better idea of how this pans out by the weekend...

Cheers

Pete

[greenglade]

We now have the handle fitted (loosely) to the cab, a fair bit of work involved on this little thing.



Continuing the discussion on Bowden cables, from what I can tell Gresley's pacific's always had Bowden certainly that's how its written in RCTS 2A. There's also a good picture from 1928 showing an A3 cab with Bowden cables so I think it's safe to say that they were always there, unless of course, someone has proof otherwise...

Pete

[greenglade]

It's been pointed out that the handle is too tall...looking again at pictures it's clear that it is..As stated in my write up on the main forum pages and Facebook, I followed Don's dimensions for the handle, perhaps he was thinking or practicality....anyway...I'll adjust the handle tomorrow...cheers

[greenglade]

Handle mark 2... I think this is much closer, the bracket now looks a little short and high but I'll leave that until the draincocks are connected as I want the fully 'open/closed' positions in the cab to match those of the draincocks, that's a little way off yet...



Pete