Mickoo's BR modelling

[mickoo]

The class 84 headcode panel is also slightly lower and gives them a distinctive underbite jaw appearance.

Windscreens should all be the same as I think that was a common component designated by the BR design panel, what throws it off are the subtle differences in corner posts. Both the driver and second man screens taper inward at the top.

The AL2 is distinct in being the only class with no roll under of the side panels, the joint being 90° except the front and corners which have a small roll under.

Class AL3 are the shortest of the lot and that's a mainly why I like them, they appear more compact and purposeful, plus I like the cluttered swing link bogie design.

Class 81 and 85 are all but identical, AEI built the AL1 and BR built the AL5 but with AEI equipment, the only change was the body side construction, the AL1 is a full trough smooth sided design from cant rail to solebar and the roof panels are removable for access. The AL5 has a cut down body side which is integral from below the grills to the solebar. The whole section of roof including the side grills comes off as several sections.

AL6 is a direct descendent of AL5, the only changes were to the cab front below the windscreen and cab roof profile, they also went from bogie suspended motors with flexible drives to axle hung nose suspended motors with catastrophic results. The unsprung mass went from 0.75t on the AL1-5 to 1.5 - 2.5t (depending on sources) on the AL6 and within a few years they pounded the WCML into the ground and had to be limited to 80mph eventually.

A redesign of the suspension with external springs helped but the rubber insert (SAAB) wheels was the biggest win, whilst the unsprung mass didn't change it now had a flexible barrier between it and the rim. Modified engines were passed for 100 but the remaining were limited to 80 and freight duties, parcels or extra/secondary passenger services at 80mph.

The flexicoil bogie was further refined on three examples as test beds for the 87, other than that and the change from three to two screens there's visually little differences between 86 and 87.

 

[mickoo]

So there'll be AL1, AL2, AL3, AL4, AL5, AL6 and an 87?

We'll see

 

[Matt Rogers]

Windscreens should all be the same as I think that was a common component designated by the BR design panel, what throws it off are the subtle differences in corner posts. Both the driver and second man screens taper inward at the top.

This is what I thought, but I've started to discount it in recent years, there are enough differences between the cabs that while some general design principles and the layout of controls inside the cab were similar, I don't think BR got that technical with the specific details. Hence the obvious differences you can see between the classes

But, I am more than happy to be corrected on this, should anyone ever find the original BR specification documents. They might be in the Kew archive, which has been on my todo list to check for some time now.

I have to admit I've been more focused on details for my 81, so never measured the windscreens on the 83 my one of my many visits to Barrowhill, so can't quote you the actual values.

Regards

 

[mickoo]

This is what I thought, but I've started to discount it in recent years, there are enough differences between the cabs that while some general design principles and the layout of controls inside the cab were similar, I don't think BR got that technical with the specific details. Hence the obvious differences you can see between the classes

But, I am more than happy to be corrected on this, should anyone ever find the original BR specification documents. They might be in the Kew archive, which has been on my todo list to check for some time now.

I have to admit I've been more focused on details for my 81, so never measured the windscreens on the 83 my one of my many visits to Barrowhill, so can't quote you the actual values.

Regards

I asked NRM if I could stand on the buffers of the AL4 and measure the screens and headcode panel, a polite but firm 'no' was the response.
I do need to get to Barrowhill at some point and try to get some decent roof shots.

You may well be right on the screens but my gut feeling is that something like that would all (logically) come from a common source.

 

[mickoo]

For a low and dirty first pass at 50 microns it's not too shabby, straight out of the printer, rinse and cure and quick blow over with paint to reveal all the issues, the intention ere is to show, not hide any issues. Some are orientation related, some are support and sacrificial parts related and a few CAD ones.

The circles of doom on the cab roof front and centre are layer lines and common to all curved surfaces in that particular axis, most will go at 20 microns and those that are left are easily sanded down, I tend to orientate the model to place those in an area that's easiest to clean up. I term that pushing or moving the issue, you can't resolve it so push somewhere where it's easiest to post process.

There's also an artifact on the top left of the cab roof, that's a damaged part of the FEP screen, you can barely see or feel it but the results of just a minor deficiency are clear to see on the print.

Two solutions, three actually, change the FEP (tedious time chore for an area 5 mm sq), move the model to clear the area (hard with big parts like this), push the error to an area easier to clean up in post processing.

The basic shell is neat and straight but a slight swaging of the body side nearer the centre on the engine, the cross bracing helped but there is still a small warp here and you can see the shadow in the paint from the top rear cant rail area to near the bottom of the rear hand rail opening. I had the same on the VL80 and EM1, more sacrificial bracing will help as well as a sacrificial extension on the rear, that all adds extra size, cost in resin and time so I might explore some alternative internal features and get to grips with that issue.

Other than that there's some minor surface ribs which soon dress smooth after a good filler primer and light rub with 1200 wet n dry.

I'm still not sure the windscreen depth is right, it matches the drawings I have and rough scaling from photos but somehow it looks a bit deep, it might be a visual thing with no windscreen in place or buffer beam.

Overall for a first shot I'm 90% happy and can move on to details, windscreen concepts and revise the shell, maybe two halves front and rear or three sections, cabs and one big mid section.

 

[mickoo]

More AL3 progress, I can just about get half of the loco in the printer and cure unit so that defines where the split points will be, sadly one is right across a window, not an issue in later days as it was replaced by a grill which are all drop in extras.

Not sure how to get around the rubber gaskets on the others though, it's be nice to add them to the main body print but they're then a high risk aspect that can (if damaged, misprinted) trash a whole print.

The kick plates do have the vertical ribs, just that the camera hasn't picked them out and I still need to add the sand filler lids as low relief objects on the main body.

The buffer beam is screwed in place for easy removal and main body print risk reduction and optimum orientation aspects, there's a big slab across the nose base and rebates inside for 10BA nuts, the same goes for the six holes along the sides which is where the brass slab floor will secure to. The other holes at the far end are for bolting the two halves together.

I've done some post processing but it needs more to be showroom smooth, though a lot of that won't be necessary when printed at 20-30 microns. Having said that it takes about 20 mins with wet n dry to smooth the 20 hr print model at 50 microns, printing at 30 microns will push the print time to about 37 hrs. You kind of have to wonder which is the best option.

The second inner grill recess is not deep enough, the leading one is the correct depth. The roof will be a thin brass sheet bonded onto the whole body and thin strips of brass will then be secured to that to replicate the side panels, that's the plan anyway.

Still not sure the cab screen is the right depth and the headcoed might need a tweak to make it a fraction narrower, it does however all look a bit better with the buffer beam on and making it easier to judge proportions.

The door beading needs to be pulled in a bit as it's a bit too proud and the same area is failing on the RH side, not sure why as this is the third print and all with different orientations and rotation on the FEP, ordinarily I suspect a corrupt file but these are three different files and the CAD master is perfect, something to ponder on.

 

[richard carr]

That looks magnificent Mick.

As for the rubber gaskets on the side windows, I think that could be an etch looking at the photos you posted earlier.
The one on the side cab window is just a bit of paint, a nice thin black line.

I hope you can bring the prints on Sunday.


Richard

 

[Stephen]

I hope you can bring the prints on Sunday.


Richard

I'll 'second' that request! Oh and your AC-6!

Cheers,

Stephen

 

[mickoo]

More AL3 work, what can I say? Wibble and wibble thrice over.

For once it actually sort of looks like it should, there are still some niggles but for a test pig it's been helpful to find what does and doesn't work. The air tanks were a throw caution to the wind and print the lot (sans pipework and glands) and see what happens and amazingly it worked so I can go back and add the missing details and move on from there. Currently they're just held on with double sided tape.

I think the tanks and framework are common across all the classes but will need to check, the pipework though might vary.

I'm out of time to start adding more roof detail, it's also pointless as the roof needs a thin brass sheet bonded to the top with angle at the edges to hold the thin covers.

The buffer stocks were blagged from a JLTRT 47 (sadly they have to go back as well) and look pretty close to those fitted to 83's, good enough for me anyway, I don't think anyone does these as castings anymore so I'll need to look into making new masters and getting a bag full cast up. The buffers I'll have to try and source from somewhere as well.

Body window frames will be NS etches as will the cab front screens and side windows, I'll also do the sand filler hatches in etch as well and possibly the buffer beam for strength and soldering on the brass castings.

I might get a little more time to add the handrails before heading out the door tomorrow to Stafford, we'll see.

 

[James]

That's superb!

 

[mickoo]

That's superb!

Not quite sure I'd go that far it's growing on me though and I've always wanted a good AC electric or two.

 

[Nigel Smith]

I do like the early electric locomotives

 

[cmax]

Well, Mick, it may only be a test print, but what superb craftsmanship.

 

[richard carr]

Oh dear I'm going to have to electrify masborough !

Thats just great

Richard

 

[mickoo]

Oh dear I'm going to have to electrify masborough !

Thats just great

Richard

Yes you are and MAS please

The AL3 is not there yet but it's all a lot closer than it was two weeks ago

 

[Clarence3815]

Won`t the new owner of MMI be able to help with buffers Mick?

 

[mickoo]

Won`t the new owner of MMI be able to help with buffers Mick?

Quite possibly, I will be meeting Iain at Stafford to hand over the last B1 brush up castings so will ask. These are quite old castings and from CAD so they're layered and not very......how shall we say....2025 technology.

Ideally I need a new master and new castings and that's the route I'd rather go.

 

[Clarence3815]

Sorted!

 

[40126]

Hey Mickoo,

Wish i’d Caught up on this before Saturday & our very brief hello would’ve been a lot longer. I know Buzz have made an 84, just can’t believe other manufacturers, in all gauges, haven’t done all the electric variants before. I loved seeing the 81 82 83 84 & 85’s a lot more than the 86 & 87’s, around brum & wolves in the late 70’s early 80’s.

Steve

 

[mickoo]

Hey Mickoo,

Wish i’d Caught up on this before Saturday & our very brief hello would’ve been a lot longer. I know Buzz have made an 84, just can’t believe other manufacturers, in all gauges, haven’t done all the electric variants before. I loved seeing the 81 82 83 84 & 85’s a lot more than the 86 & 87’s, around brum & wolves in the late 70’s early 80’s.

Steve

It was in a box on the stand for peeps to look over if they wanted, consensus is it captures the 'look'. Sadly I've just realised the cab roof rear and well deck are incorrect so it's currently getting a rebuild in CAD but the AL1 (body only) will be printed first in the next few days.

I liked them all, 81-87 but roarers were always a good bag, plenty of them around in 79-82, managed to see the last two 84's, not sure if that was operational or at Crewe works on one of the many visits I did there.

Last time I saw Roarers was 83-84 after I started work, we had courses in Wolverton and I used to head lineside after class and before pub with mates. I regret not doing more.