A powered Armstrong Whitworth D9 - plans included.

[JCL]

It's practically finished now. As far as I can see, the chassis is pretty much there. I've not included any brake rigging as I think it'd be too fragile, but I might add the fixing points where necessary so they can be added later. Pretty much everything else is there. I do need to count the rivets once more. 

 

 

With regards to the axleboxes, I contacted the gentleman that runs the Derby Sulzers website, and he sent me a much better version of one of the photos on the site. That photo had smaller compression artifacts and so much better detail. It allowed me to rework the axleboxes as well as the rest of the springs, etc.

 

 

 

After doing a lot of squinting, I've found that the step on the front is a later addition, and that there was also a modification to the roof. The original roof profile also has a hump in it towards the flat end - was this removed later?

 

 

The photo of the hump below is a bit of a guess. The height is from the profile drawing (which, to be fair, is quite coarse), but the width is a best guess. Does anyone have any thoughts on this?

 

 

The next step are the holes to drill for the handrails, etc.

 

Edited November 5, 2020 by JCL
hump photo added

[Wagonmaster]

Hi Jason,

 

That's looking very good! You have been busy!

 

A couple of points, if I could. I'm guessing that you intend some parts to be fitted later, due to them being too fragile as a print? If so, then please ignore my comments. There are no guard irons, easily fitted though, as are the cab steps. Looking at a photo of the 'flat end', there is a small projection above the right hand window. A horn perhaps? 

 

Cab handrails you mentioned are are easily sorted. Again, looking at photos, are there any angle sections either side of the windows, or is that just the window frames and the way they were picked up by the camera?

 

What chassis have you in mind for this and what sort of fixing points are there?

 

Eager to have a go at this!

[JCL]

Hi there, yep, steps, horns, pipes, guard irons, etc will need to be added later as they'll be too fragile. Where appropriate, (e.g. handrail knobs, horns) I'll be "drilling" holes to take them. The holes will be a bit smaller than necessary so you can drill them out to the right diameter. When it's finally finished, I'll give a list of things that will need to be added - possibly using the photo below.

 

One thing, I'll be printing it for myself when my printer turns up here in Canada, but I won't be printing it on Shapeways. I'm not looking to make money off it, as really I'm doing it for myself, so I'll also make the file available if anyone wants to print it off themselves.

 

Something that will help is the photo that I was given by David Hills of the Derby Sulzer website. He has told me that he has no problems with me adding it to this thread, especially as they were A-W publicity shots. It's a lot clearer than the other photos I have.

 

So the chassis is interesting. Either it will be a 'do it yourself' job, or I could knock a chassis 3D print file up. Problem with 3D printed ones is that they will either be flexible or will be fragile. The way I'll be doing it is to reuse the Hornby class 31 motor bogie. There are compromises with this though - wheelbase is close, but slightly out, and the wheels are disc wheels (there's info in this thread about this). To help with the wheelbase difference, I'll slightly change the axlebox positions on an alternative version so that they match the Hornby bogie wheelbase.

 

Pony trucks - I can either put something basic together, or they could be the modeller's own.

 

With regards to fixing points for the do it yourself chassis, I'm open to suggestions.

 

Does that help?

 

Jason

 

Updated to add that I've just noticed that this photo shows the louvre on the side of the bonnet has been removed and a plate with holes in it has replaced it. To see the full image, click on it, then right click on "view image in a new tab" then click on it again.

Edited November 5, 2020 by JCL

[Wagonmaster]

Thanks Jason, that does help a lot!  I'll have a think about the chassis as I would like to use spoked wheels if possible.

 

Steve

[JCL]

 

I've been looking at the changes that were made to the loco and so far I've found the following:

1. The fins welded to the bonnet seem to be a later addition
2. The louvre panel was replaced by a sheet of metal with holes in it
3. A grab was added
4. The hump - I'm not convinced either way that it was kept
5. The side louvres - some photos show them inset on both sides, some show them inset on only one side, this seems to be the latter.
6. Not shown, is the step above the pipes on the opposite end. I've shown this in a different photo.

I'm going to model this as close to original condition as I can. 

 

Below are a couple of photos showing the location of the .4mm holes I've drilled for handrails, pipes and the horns. I've not added holes for the lamp irons. Wagpnmaster, is this something that would help?

 

 

 

[JCL]

Gah, there is one thing - a bit of an elephant in the room. Although I'm happy with the model so far, I do realise the roof curve across the ends of the machine isn't quite the right profile. I'll do my best to get it closer, but if I can't get an exact match, it may need a little bit of sanding to get the required shape.

[Wagonmaster]

Hi Jason,

 

Yes, all that helps to get the locations right, thank you. I didn't mention the lamp irons as I wasn't sure of the best way to tackle them. They are basically flat strips with an angle in them. Flat strips don't go in round holes too well, so I thought gluing them on might be a better option?

 

I'll try and find that photograph showing another detail I wasn't sure about

 

Steve 

[JCL]

Do the bought ones have pegs in their back face? Also, the hole doesn't have to be round.  

Edited November 6, 2020 by JCL

[Wagonmaster]

I'm not sure about that. The ones I have used have are thin strips of etched brass that are folded and soldered to the body. They have been in the kits I've made or can be bought separately. Obviously soldering isn't an option here, but glue is.

 

I think spares for RTR models are available, but I haven't used these so couldn't comment.

[JCL]

I’ve had notice that my printer will be turning up From HK on Friday. We tend to take this sort of thing with a pinch of salt on Vancouver Island, so one day next week is probably more realistic.

 

I’ll quickly redo the axle box locations and fixing points for my version so they work with the bogie, and after calibrating and testing the printer, I’ll print one of these off. As soon as it’s done, I’ll put pictures up on here.

[Wagonmaster]

All sounds good! Just a query over the bogie hou are using. I think you mentioned it was a Hornby Class 31 bogie? Is this of the later type from the Railroad range?

Edited November 10, 2020 by Wagpnmaster

[JCL]

Ah, I got it a long time ago, all I can say is it looks like this. ^ I took the sides off it and added a decoder.

 

Here it is superimposed on the drawing to show you how far out the wheelbase is.

 

 

Does anyone have any views on the pivot point for the pony trucks?

 

Jason

 

[Wagonmaster]

Thanks for that. It does look like the newer bogie of a Railroad Class 31. I wonder how easy they are to re-wheel?

[Enterprisingwestern]

On 06/11/2020 at 23:15, JCL said:

the .4mm holes I've drilled for handrails, pipes and the horns.

 

Could you make these as dimples so the correct sized holes can be drilled?, I for one use 0.3mm wire for handrails, and if the lamp brackets of choice don't come with a mounting spigot it's an easy enough job to solder a bit of brass wire on the back to make them so.

 

31 minutes ago, Wagpnmaster said:

Thanks for that. It does look like the newer bogie of a Railroad Class 31. I wonder how easy they are to re-wheel?

 

Very easy, but, the centre wheel is correctly of a smaller diameter with the corresponding axle hole a tad lower, so that would need addressing.

 

Mike.

[Michael Edge]

Look up Baldry's rule for the pony truck pivots - it really does work but it's not always possible. See the BR 1-Co-Co-1s for an example of where theoretical pivot points don't work and the rather complicated solution to it. Getting them as near as possible to the rule is better than ignoring it though.

[JCL]

Thank you for that. I found a link on the Scalefour website here: https://www.scalefour.org/resources/baldry.html .

 

The good thing is that I can use the formula and test a few versions of the pivot. The pony trucks being small, it won't cost too much in resin.

[cheesysmith]

If I am reading this right, you need a 14`3" wheelbase? Can I suggest the Heljan class 47 bogie? This would be 1mm too long, but the centre axle is just a idle wheel so could be adjusted, and they are easy to rewheel having 2mm axles.

[JCL]

Thank you for that, I'll have a look into it. 

[Wagonmaster]

On 12/11/2020 at 09:55, cheesysmith said:

If I am reading this right, you need a 14`3" wheelbase? Can I suggest the Heljan class 47 bogie? This would be 1mm too long, but the centre axle is just a idle wheel so could be adjusted, and they are easy to rewheel having 2mm axles.

 

The Heljan 47 bogie is driven by the centrally mounted can motor, whereas the the Hornby Railroad 31 has the motor built in. Going to a compromise either way, but I think I'd use the 31.

[JCL]

Printer delivery is now nominally on Monday, so I'll keep you posted.

[JCL]

The good news is that the printer has turned up. It had quite the journey. The resin that came with it is crystal clear, so that'll be interesting.

 

I've been thinking about mounting the motor and come up with the design below (which is definitely up for discussion!) The idea is that there are two bars (in blue) that run from one side to the other. Dead centre is a 2mm hole to accept the screw (in yellow). The motor doesn't have enough of an overhang at each end, so my thought is that styrene/brass with its own 2mm hole is epoxied onto each end of the motor, which is then located using the screws. I could also add a guide each side of the motor to make sure it's dead centre.

 

What do you think?

 

Ponies next.

 

[Enterprisingwestern]

22 minutes ago, JCL said:

What do you think?

 

Instead of the complication of dis-similar materials, and attempting to epoxy things in the right place, wouldn't it be better/easier to 3d print these mountings, or even a complete new bogie frame/mounting assembly?

 

Mike.

[JCL]

Thanks Mike, I've had another couple of thoughts, which, if they work, will do the job (and make more sense than my previous message)

 

In other news - good god! My computer had a fit this morning and the folder I have on it called 'trains' - basically everything I have on the the subject - disappeared into the ether. Nothing in the recycle bin either. Checked the off-site backup I do (iDrive) and it doesn't seem to be on there either. In the end I did a full search of the computer, and there seems to be a bit of folder corruption which I'm going to have to run a check on (I'm a website designer, I can't afford to lose files)

 

In the end, I've found an autosave copy in a temp files folder.

Looks like I've got some hard drive and backup tests to run tomorrow before I do anything else.

Edited November 25, 2020 by JCL

[JCL]

Hi all

 

The file is now backed up remotely, and on a pen drive, and barring changes after testing, the drawing is finished.
 

Today I was able to run the file through the printer and print the following chassis.

 

 

After cleaning off the gunk, drying it, and removing the supports, I did a test insert of the motor bogie, and it fitted perfectly.

 

Yesterday the penny dropped - the chassis was always going to be printed separately from the body. This means that it would be really easy to secure it using an L shaped beam at each end with a hole dead centre. The vertical part of the L butts up against each end, and the horizontal part of the L keeps the chassis at the right height. Before the body is glued to the chassis, I just need open up the hole to the right diameter, and drive a small screw into each end to keep everything in place.

Here’s the chassis with the motor bogie slipped in.

 

 

The end spacers have 2mm holes that match end spacers in the body so they can be bolted together (minimizing any kind of warpage), and those two beams either side of the motor don’t just hold the motor in, but provide the mounts for the pony trucks.

 

Really pleased so far as the only changes I need to make are cosmetic, so I’ll set the body print off tomorrow after adding a few more details. After seeing @woko’s brilliant thread in the 3D printing section, for my own model I’m going to add vacuum pipes and lamp irons. I know they’re delicate, but I’m not aiming to manhandle it that roughly.

 

@MikeTrice, the print took an hour and a half to complete and the Lychee software supports are so good that I can hardly see where they attached to the model.

 

So all in all, a much better day than yesterday!

Edited November 26, 2020 by JCL
Deviation from English

[Wagonmaster]

That is all brilliant news JCL. Your solution to the motor and chassis issue seems a good one. Personally, I prefer to have a separate motor/chassis assembly that screws in under the body.

 

Looking forward to seeing your first print of the Universal.