OO gauge GWR Mogul and Prairie

[Chuffer Davies]

1 hour ago, 1466 said:

Assuming there is commonality in the mechanicals of the mogul and prairie, an improved 30 to 1 gear ratio would be welcome . Especially if the gear with a one axle  of quartered wheels were to be available as a retro fit . In other words , drop out the old and substitute one axle with new 30 to 1  for a mogul .  Different wheel size for prairie ? Full marks to Dapol for listening and learning . Implications for the Manor but I’ve already preordered an Accurascale one . More pain in the wallet!

 

 

Sorry to disappoint but whilst the wheels are the same between the Mogul and Prairie it will definitely not be a simple axle swap to change the gear ratios.  If it were only a change to the gear on the axle it would require a much larger diameter gear which would then not fit.  My money is on a different worm and pinion ratio, that way Dapol can then reuse the chassis castings from the Mogul.

Frank

[BenL]

28 minutes ago, Miss Prism said:

 

They're not too bad in my view, and the same as on the Mogul. There are two inserts on the Dapol tool, one for the tall safety valve and another for the short cover. These drawings do lack a bit of side curvature, which was very subtle on the originals, and there was some variation in the originals, all being hand spun of course.

 

Don't expect the Dapol EPs to have the correct match of mechanical and cosmetic detail at this stage.

 

5190 was outshopped with a short safety valve cover (in 1934).

 

 

Many thanks for your thoughts and reassurance on the safety valve covers Miss Prism.

 

It's the 'G W R' liveried 5150 I'm focused on, and I understood she was outshopped with a tall safety valve cover. But as you say, EPs don't always have the correct combination of details. However, given it's presumably a decoration sample, I hope they've noted the incorrect positioning of the route disc (should be above the number plate not on the side shutters on 5150 in 'G W R' livery).

[Miss Prism]

Yes, 5150 had a tall safety valve cover when new, and initially without a cab shutter. You're right about the route disc position of course.

 

[1466]

33 minutes ago, Chuffer Davies said:

Sorry to disappoint but whilst the wheels are the same between the Mogul and Prairie it will definitely not be a simple axle swap to change the gear ratios.  If it were only a change to the gear on the axle it would require a much larger diameter gear which would then not fit.  My money is on a different worm and pinion ratio, that way Dapol can then reuse the chassis castings from the Mogul.

Frank

Thanks Frank , that’s helpful. 

 

34 minutes ago, Chuffer Davies said:

Sorry to disappoint but whilst the wheels are the same between the Mogul and Prairie it will definitely not be a simple axle swap to change the gear ratios.  If it were only a change to the gear on the axle it would require a much larger diameter gear which would then not fit.  My money is on a different worm and pinion ratio, that way Dapol can then reuse the chassis castings from the Mogul.

Frank

Thanks Frank , that is helpful . I would be prepared to buy a new 30 to 1 worm and pinion by themselves to retrofit to my mogul . It is still on the 2do list awaiting conversion to EM . Your planned kit to convert to tender drive is tempting but I’d like to  conserve as much as I can from the Dapol mechanism . Please keep us updated, though , with your etched kit and your progress . Regards. Ken 

[melmerby]

Mmm.

I find that Dapol have either re-acted impossibly quickly to concerns about Slidebar/Crossheads, Gear ratio & Firebox glow or something went seriously wrong in Mogul land between design and production.

 

As to changing gear ratio, I suspect you will need to change the motor worm, the intermediate gears and the axle gear to fit the 30:1, which with careful design might fit in the current chassis block without rework.

[coeurdelyon]

2 hours ago, Miss Prism said:

Dreadful chimney. Here's what it should look like.

 

 

[coeurdelyon]

Hi, Why is the chimney dreadful, it conforms to the drawing you attached so please advise where it is wrong

 

Thanks

Richard

[melmerby]

37 minutes ago, coeurdelyon said:

Hi, Why is the chimney dreadful, it conforms to the drawing you attached so please advise where it is wrong

 

Thanks

Richard

I doesn't look like the drawing to me.

It looks more like a stovepipe with a copper cap.

Edited February 5, 2021 by melmerby

[coeurdelyon]

Hi Keith,

It may be the photograph, but I can assure you it is within a few thou' of the dimensions scaled off the drawing

 

Thanks

Richard

[The Johnster]

4 hours ago, Miss Prism said:

I know 5190 was in lined black for a while, but is there a pic in that state with the Gill Sans British Railways lettering?
 

Perhaps a safer bet would have been 41xx series built between 1/6/48 and 31/9/49 when the unicycling lion was introduced, unless some of those carried plain black livery.  These were in the 416x range.

 

6 hours ago, No Decorum said:

The motion looks very odd to me; as if it’s either plastic or painted, not to mention the black pin or screw fixing the rods to the wheels.

A bit like an Airfix kit 61xx I built back in the day, with the motion picked out in Humbrol enamel silver.

Edited February 5, 2021 by The Johnster

[Chuffer Davies]

2 hours ago, 1466 said:Your planned kit to convert to tender drive is tempting but I’d like to  conserve as much as I can from the Dapol mechanism . Please keep us updated, though , with your etched kit and your progress . Regards. Ken 

Hi Ken,

I’ve just started the build this afternoon.  If your preference is to retain as much of Dapol’s mechanism as possible then the Flexichas solution under development from Brassmasters would be a better option for you.  
It would be best to check with Dapol whether the gearing for the Prairie can readily be reverse engineered into the Mogul.  As a minimum you would need to pull the worm off the motor’s shaft and swap out the top pinion gear.  That could be anything from dead simple to almost impossible depending on how firmly the worm is attached to the motor.

Best of luck,

Frank

[1466]

Thanks Frank . I’m committed to the Brassmaster’s easichassis route . Here’s hoping the worm will respond to a worm puller !  Otherwise , as my Dad used to say  “Use a bigger hammer “.

Ken 

[David Bigcheeseplant]

As I pointed out earlier and several others after me the chimney looks totaly wrong, the front end smokebox door chimney etc are the face of a loco and the Dapol model does not look right at all, Even the old Airfix model the Chimney seemed right although the smokebox door was wrong.

 

The Dapol Chimney looks more like a cast iron chimney on a small prarie, than the wide business type found on a large prairie, it just look wrong, firebox glow or other gimicks I would rather have the proprotions correct. 

[7007GreatWestern]

 

Left: Dapol Large Prairie Chimney

Centre: Chimney of 4160 on West Somerset Railway

Right: Hornby Large Prairie Chimney

 

It looks like the cap of the Dapol chimney is a separate part. That would make sense if it's turned copper.......

[coeurdelyon]

Hi David,

Trust you are keeping well.

I have attached a couple of pictures, a 7mm scale model built from a Martin Finney kit which are regarded as very accurate and well designed, plus a picture of the Dapol decorated sample for review and obviously requires some paint corrections, but if you compare the chimneys I think you will find they are very similar. 

Thanks,

Best Richard

[mdvle]

8 hours ago, Miss Prism said:

 

There's something that doesn't look right to me - have those pictures been squashed longitudinally?

 

 

Bad website design - if the browser window isn't wide enough it does indeed squish the images.

 

Either make your browser bigger, or right click on the images and select view image to get the image only - where it will be scaled instead of squished, and you can make it bigger and scroll.

 

 

[melmerby]

What's with the Southern Green?

 

Green steps?

Edited February 5, 2021 by melmerby

[melmerby]

17 minutes ago, mdvle said:

 

Bad website design - if the browser window isn't wide enough it does indeed squish the images.

 

Either make your browser bigger, or right click on the images and select view image to get the image only - where it will be scaled instead of squished, and you can make it bigger and scroll.

 

 

Bad original photos IMHO

Copy image, paste into graphics program view on 40" screen - still squished, although not by as much.

[Miss Prism]

2 hours ago, mdvle said:

Bad website design - if the browser window isn't wide enough it does indeed squish the images.

 

Either make your browser bigger, or right click on the images and select view image to get the image only - where it will be scaled instead of squished, and you can make it bigger and scroll.

 

Thanks for confirming that Dapol is certified mad.

 

[kandc_au]

14 hours ago, coeurdelyon said:

Hi Keith,

It may be the photograph, but I can assure you it is within a few thou' of the dimensions scaled off the drawing

 

Thanks

Richard

Richard,
I haven't read all the conversation, just this last part, BUT if the issue is in the photo, would it not be better to get more photo's taken that don't distort the look.
I would have thought that if pics are put up here whether they be samples or not, one would ensure they do represent what is trying to be sold, and obviously in this case from what you are saying, it appears, the pics do NOT fairly represent the model!
Just my thoughts.
Khris

[TheSignalEngineer]

On 26/01/2021 at 21:03, Miss Prism said:

Powerful yes, good acceleration yes, but I doubt the large prairies got above 65mph.

 

I travelled behind a few on excursions from Birmingham to Great Malvern. Not many stops, on the run through Hagley and Blakedown to the Kidderminster stop the top speed would be around 60mph.

[The Johnster]

They should, if not overloaded, be theoretically capable of the same speed as a 43xx, Manor, or Grange, but would rarely be required to run much above 60 or so to meet the timings on most of their normal work.  

 

[Les1952]

16 hours ago, Miss Prism said:

 

Thanks for confirming that Dapol is certified mad.

 

 

Not completely - they don't post on RMWeb.......... 

 

[rembrow]

1 hour ago, Les1952 said:

 

Not completely - they don't post on RMWeb.......... 

 

But they do. Coeurdelyon, who has been posting today about the Prairie chimney in the model, is Richard Webster, development manager of Dapol and Lionheart.

[Hilux5972]

Looking closer at the safety valve cover, the black parts look like seperate fittings. Could this possibly be a turned brass cover?