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Modelling Stones Ventilators? (4mm)

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37 minutes ago, Barry O said:

I think the ones I saw were either all open or all closed or all somewhere in  between..ie they work off a single control handle.

I am not certain you can print fine enough to give the glass 'edge's? You also need quite a few of them (14 to 16 per coach).

I has mine etched in Nickel Silver as they look more like the glass (I did try scribed perspex but it doesn't look right for some reason.)

Baz

I think Guy was thinking about the proportion in a coach rather than a single ventilator. 

 

I would go with 50/50. If you don't like the look of one sort you fit them to the unseen side of the carriage. 

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On 23/07/2019 at 10:44, Guy Rixon said:

I would make the body of the vent according to the holes in the Comet sides, and that sets the size of the rotating panels. It would be useful to have accurate measurements of the frame.

I haven't got an accurate measurement but from calculations and Jenkinson's drawings the size over the frame would be approx 230mm high by 625mm wide, or 3mm x 8.2mm at 4mm scale.

The holes in the Comet sides would make it difficult to get an accurate size for the vents. The size of the rotating vanes including the metal carriers top and bottom is approx 190mm, so 2.5mm at 4mm scale. The holes are 2mm high by 8mm wide, although some are probably only 1.9mm as they won't take a piece of 80 thou plastic. the other difficulty is that they don't all lie in the same place on the etch. On my coaches the space from the top of the window to the roof line varies between approx 3.5mm and 3.8mm. There needs to be approx 0.5mm space top and bottom to allow for the coach framing in the prototype.

I'm beginning to wonder if there were actually different heights or whether the Comet etches are slightly at fault in the sizing of the window frames.

 

On 23/07/2019 at 10:44, Guy Rixon said:

What mix of closed and part-open vents would please? The printing won't cope well with fully-opened vents (can't print fine enough to represent the end-on glass panels), but I could do panels open enough to present a saw-tooth profile.

As said in one of the other posts all of the vanes in the set worked together. They could be angled to get air in or take it out by the passengers, Which way they were angled depended on  the direction of travel and the required air flow. I've seen pictures with all vents open, all vents closed and a mixture of the two.

 

Eric

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How about this:

  • Make the part of the print that plugs into the side 2.00mm tall (and I'll need to know the length as well). Filing will be needed for the undersized apertures in the etch.
  • Make the carriers on the rotating panes half a scale inch tall at top and bottom, so that the size of the modelled panes comes out to 2.33mm tall.
  • Model the carriers in front of the etched side, sticking out from the plug part of the print; i.e. it's T-shaped when seen from above. The overall frame of the vent will stick out further still.
  • Half the vents on the sprue will be modelled as closed and half as part-open, but in each vent the panes will be at the same angle.
  • The number of vents on each sprue will be high enough to take the print above Shapeways' price floor (otherwise we pay them more per vent) and will be enough to do one coach if that's a higher number.
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I've done a bit of measuring on some Comet sides I have made up for fitting to donors. The holes seem a bit variable even within the same etch but we are talking about very small measurements.

The figures are based across a number of measurements on each etch.

 

47418489_CometVentSizes.jpg.872fc396c68055e21376d4a8797eb6ea.jpg

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On 29/07/2019 at 13:44, Guy Rixon said:
  • Make the part of the print that plugs into the side 2.00mm tall (and I'll need to know the length as well). Filing will be needed for the undersized apertures in the etch.
  • Make the carriers on the rotating panes half a scale inch tall at top and bottom, so that the size of the modelled panes comes out to 2.33mm tall.
  • Model the carriers in front of the etched side, sticking out from the plug part of the print; i.e. it's T-shaped when seen from above. The overall frame of the vent will stick out further still.

Working from my rough details of a Midland coach I've come up with this drawing. Not sure if this is what you mean but it would cover the hole in the coach sides.

 

899063955_StonesVentSketch.jpg.872c3aa85cbee29f5dc44ab190da89d6.jpg

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On 29/07/2019 at 13:44, Guy Rixon said:

How about this:

  • Make the part of the print that plugs into the side 2.00mm tall (and I'll need to know the length as well). Filing will be needed for the undersized apertures in the etch.
  • Make the carriers on the rotating panes half a scale inch tall at top and bottom, so that the size of the modelled panes comes out to 2.33mm tall.
  • Model the carriers in front of the etched side, sticking out from the plug part of the print; i.e. it's T-shaped when seen from above. The overall frame of the vent will stick out further still.
  • Half the vents on the sprue will be modelled as closed and half as part-open, but in each vent the panes will be at the same angle.
  • The number of vents on each sprue will be high enough to take the print above Shapeways' price floor (otherwise we pay them more per vent) and will be enough to do one coach if that's a higher number.

Guy

I'm just starting glazing three coaches prior to final assembly. I was wondering if you had any more thoughts on whether it was possible to print these or not. 

Eric 

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Eric, yes I think it's feasible and I shall make the CAD when possible; in fact I've started it. I've had a difficult summer with work and family commitments, so this model has been delayed. I hope to get it done in the next week. After that, there's a turn-around time of maybe two weeks while I get a test print from Shapeways and check it, and then you can order. If you're desperate, and feeling lucky, I can the product available without a test print; but this is new shape, so better to wait for a test if pos.

 

Cheers,

Guy

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4 hours ago, Guy Rixon said:

Eric, yes I think it's feasible and I shall make the CAD when possible; in fact I've started it. I've had a difficult summer with work and family commitments, so this model has been delayed. I hope to get it done in the next week. After that, there's a turn-around time of maybe two weeks while I get a test print from Shapeways and check it, and then you can order. If you're desperate, and feeling lucky, I can the product available without a test print; but this is new shape, so better to wait for a test if pos.

 

Cheers,

Guy

Thanks Guy.

I will be busy for the next two or three of weeks so not much time for modelling. I'm just getting the underframe and roof ready for each of the three P1/P2 coaches which will take 38 vents altogether.

Eric

 

Edited by TheSignalEngineer

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The test-shot of the Stones ventilators is now back from Shapeways. There are 68 vents in this print (which is about the most I can fit in for a near-minimum-price print in detail plastic), of which half are modelled closed and half with the slats opened to 45 degrees.

stones-vents-full.jpg.9aaadfe9375b85eeb5e7751b21d6d53b.jpg

 

stones-vents-close-up.jpg.fe6c0e08c83ed72a0978d379c4fed74a.jpg

 

They're a bit hard to photograph effectively!

 

To my eye, these look about right. They're made to the dimensions on the drawing in this thread, except that I had to thicken the bottom and sideframe-edges to about 1.5x scale to get them to print. The quarter-round edge above the frame is very slightly thicker than scale. The "plug" at the back of the vent is as per the drawing.

 

This is translucent resin. It will get slightly more transparent when washed (soap and water), but will go opaque white if exposed to UV light. Therefore, the parts need some high SFP varnish quite early in their life.

 

Eric, if you still want these, if you PM me a postal address, then I'll send you the test print. If it seems good to you, we'll arrange payment: cost including postage will be £8.00. If the print is not right, bin it and I'll try again. Alternatively, I can put this up as a product you can buy from my shop, but that will take longer to get to you.  Do let me know.

 

 

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Guy, you have a PM.

 

They are looking good. I will fit some to the coach sides I have got prepared ready for finishing. There are Blood & Custard and BR Maroon ones so we can get a good idea of how they look on each.

I think the three P1/P2 vestibule coaches have a total of 38 vents between them so a sheet of 68 would  do a rake of at least 5 coaches depending on the types. Side corridor stock usually had vents on one side only. I think they could also be cut down to make the smaller vents on some stock particularly restaurant cars.

When I've done them I will post the results on here if they are OK.

 

Eric

 

 

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A quick update. 

I will be doing a couple of minor alterations to my sketch in the next day or so. Guy will then update the CAD and when the next print is done they should be available to purchase if anyone is interesred.

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Interestingly timed, my etch is finally seeing the light of day soon too.  They will be available from Rumney Models from Scalefour North.  I thought Mike G had put a photo up of the finished coach with them fitted, but I see it isn't here I will ask him if I can post one.

 

Not that I was aiming for direct competition, I think they both look good - it would be interesting to compare them side by side for a variety of open and closed windows within a coach - though I'm not convinced they would.  Possibly within a rake though.

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20200130_194742.jpg.c85809a220bfd1e01c6962972af92d17.jpg

 

As suggested earlier, here is a photo of the etched version often vents on a completed D1807 TO, assembled & decorated by Mike G

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