Hornby Announce SR 4-6-0 Lord Nelson

[GrumpyPenguin]

2 hours ago, Graham_Muz said:

Then perhaps such unprototypicical curves are unacceptable in this day and age... 

As is accepting that the wheels are not far enough apart.....

 

 

[Graham_Muz]

10 hours ago, GrumpyPenguin said:

As is accepting that the wheels are not far enough apart.....

 

 

 

And have steam locos driven by electric motors... Mornington crescent!

[No Decorum]

12 hours ago, 34theletterbetweenB&D said:

That's what he did at the front end, though rather more than 'tweak' the steam passages: it was all about enlarged porting in the valves and cylinders, which combined with the much larger entrainment area of the  multiple jet ejector exhaust meant that the steam did more work in power delivery instead of overcoming back pressure, and supplied a better smokebox vacuum to draw the fire proportional to the power demand.

 

There had clearly been some doubt about the steam raising of the LN boiler, so he also tried a round top boiler, but with the improved front end that proved unnecessary. (The firebox draughting may have been looked at as well; I haven't read anything about that, but it was a regular bogey haunting UK steam designs.)

I believe the round-top boiler was a try-out for a possible Pacific, which was never produced. The original LN design was hampered by a firegrate which was flat at the back and steeply sloped at the front. Those were difficult to fire because it was difficult to get coal to cover the sloped part and all too easy to put too much on the flat part, where it wouldn’t jiggle forward as it would on a grate with a consistent slope. The early Jubilees on the LMS had a similar arrangement which contributed to their troubles. All in good time, I hope to find out if Bulleid tackled the grate.

[Graham_Muz]

55 minutes ago, No Decorum said:

I believe the round-top boiler was a try-out for a possible Pacific, which was never produced. The original LN design was hampered by a firegrate which was flat at the back and steeply sloped at the front. Those were difficult to fire because it was difficult to get coal to cover the sloped part and all too easy to put too much on the flat part, where it wouldn’t jiggle forward as it would on a grate with a consistent slope. The early Jubilees on the LMS had a similar arrangement which contributed to their troubles. All in good time, I hope to find out if Bulleid tackled the grate.

 

The grate was not changed by Bulleid due to the fact it was such a shape owing to the relative positions of the rear axle / firebox, however by concentrating the allocation of the class at Bournemouth ensured greater familiarity / experience of the engines with the crews and how to fire them to get the best performance.

[PhilH]

1 hour ago, No Decorum said:

I believe the round-top boiler was a try-out for a possible Pacific, which was never produced. The original LN design was hampered by a firegrate which was flat at the back and steeply sloped at the front. Those were difficult to fire because it was difficult to get coal to cover the sloped part and all too easy to put too much on the flat part, where it wouldn’t jiggle forward as it would on a grate with a consistent slope. The early Jubilees on the LMS had a similar arrangement which contributed to their troubles. All in good time, I hope to find out if Bulleid tackled the grate.

Further to this I had the pleasure of driving 850/30850 on the Mid Hants numerous times (and the associated not so pleasurable oiling the thing up). It certainly was a test of a fireman’s art, that change in grate gradient catching many out. Some struggled to get enough down the front (the soft blast from the Lemaitre blast pipe was not their friend here) but the biggest culprit was not getting enough on where the gradient actually changed. This was evidenced every now and then by weeping stays above this point indicating cold spots in the fire.

Edited April 10 by PhilH

[GrumpyPenguin]

2 hours ago, Graham_Muz said:

 

And have steam locos driven by electric motors... Mornington crescent!

& have them driven by the tender....

 

Way, way back I became underwhelmed by such UK things as huge tender/locomotive gaps, same again with rolling stock, flangeless driving wheels (9f's excepted), Volvo style bumpers & so on.

Then, I discovered the world of close couplings (some steam outine locomotives did cheat a litte with cabside doors/footplates but visually quite good), fully flanged wheels (& able to negociate R2) & NEM pockets - in other words European HO - far ahead of UK models albeit about three times the price. However, now the price gap has reduced.

Periodically, I think seriously about returning to UK outline & even accept the "narrow gauge" compromise, but looking at the Locomotive the subject of this thread (which would be on the wanted list) it puts me right off.

[34theletterbetweenB&D]

11 minutes ago, GrumpyPenguin said:

European HO - far ahead of UK models albeit about three times the price. However, now the price gap has reduced.

Periodically, I think seriously about returning to UK outline & even accept the "narrow gauge" compromise.

At least now RTR OO is available benefitting from many of the advances long time established in HO.

 

And the RTR choice is simple enough, OO for good looking but with underscale gauge, HO for correct gauge but ugly distortion of steam traction, both compromises necessitated by the narrowness of UK protoype.  There's a reason for P4 and P87 for any that want better...

 

19 minutes ago, GrumpyPenguin said:

...looking at the Locomotive the subject of this thread (which would be on the wanted list) it puts me right off.

That's the inherent design flaw of the subject, trying to get a boy to do a man's work. The land of wide fireboxes is the one you should look at.😎

[No Decorum]

2 hours ago, 34theletterbetweenB&D said:

At least now RTR OO is available benefitting from many of the advances long time established in HO.

 

And the RTR choice is simple enough, OO for good looking but with underscale gauge, HO for correct gauge but ugly distortion of steam traction, both compromises necessitated by the narrowness of UK protoype.  There's a reason for P4 and P87 for any that want better...

 

That's the inherent design flaw of the subject, trying to get a boy to do a man's work. The land of wide fireboxes is the one you should look at.😎

That would be France, I assume. (I’ve been reading a reprint of Chapelon: Genius of French Steam – an eye opener.) 😄

[34theletterbetweenB&D]

No, the USA. The wide firebox began its  development there well before M. Chapelon was pushed out of the womb.

 

And in the UK context, the GNR. The introduction of the  Ivatt large atlantic was the announcement here of the obselescence of the narrow firebox for maximum power steam traction. (Churchward clearly understood this, but ran out of road before his own response could be sufficiently developed.)

17 minutes ago, No Decorum said:

I’ve been reading a reprint of Chapelon: Genius of French Steam – an eye opener

While Col. Rogers does well, the yet greater eye opener is M. Chapelon's  'La Locomotive a Vapeur'; try your library service for access, unless you can find the English translation at a reasonable price. It's one of a very small number of regular bedtime reading books that I miss so much when away from home...

[Mallard60022]

20 hours ago, Graham_Muz said:

Then perhaps such unprototypicical curves are unacceptable in this day and age... 

Brilliant.

[Jack P]

It's all a compromise, my (still narrow gauge, and soon to be moved on to greener pastures) 853 has benefited hugely from the closer tender coupling and detailing pack - it will no longer run on second radius curves, but would look silly doing so anyway. I'm happy with the compromise I've struck. The next one will be in EM and i'm hoping will negotiate 3' radius curves at the very tightest!

 

Edited April 11 by Jack P