miken
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Post by miken on Nov 21, 2015 19:11:13 GMT
I'm having a go at building a 5" Dreadnought class compound engine. Started earlier this year. here are some pics. Its a really interesting loco to build because there are so many unusual features. Not least the dustbin sized cylinder of the LP engine. The tricky bit will be fitting all the pipework into the smokebox. There is quite a lot going on in there. As can be seen i am building the rebuilt version with Joy valve gear on the HP engine and slip eccentric on the LP engine. Mike
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Post by Jim on Nov 21, 2015 20:54:29 GMT
You're doing some superb work there Mike and on a very interesting prototype that's a departure from the usual prototypes modeled here. I'm really looking forward to following your build.
Jim
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Post by donashton on Nov 21, 2015 21:35:08 GMT
Nice work Mike, and a fascinating engine. Do you know if special springing or whatever was required - the weights must have been different port and starboard? Don.
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miken
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Post by miken on Nov 21, 2015 21:56:34 GMT
Nice work Mike, and a fascinating engine. Do you know if special springing or whatever was required - the weights must have been different port and starboard? Don. Hello Don, Im not quite sure what you mean. The loco has a conventional outside 2 cylinder engine that drives the rear wheels. These exhaust into the LP engine that drives the centre wheels. So I dont think the weights were different on either side. It will have leaf springs on the front carrying wheels and centre axle. With coil springs on the rear axle as shown. The 2 engines are famously not connected by coupling rods and operate more or less independently .the driver has no real control over the LP engine. I look forward to the day when I get it running up on blocks and can watch the 2 sets of driving wheels rotate in opposite directions.
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Post by donashton on Nov 22, 2015 8:24:09 GMT
My mistake Mike, now that I've opened my eyes properly, but I did not mistake the quality of work.
I look forward to further posts.
Don.
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pault
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Post by pault on Nov 22, 2015 10:55:01 GMT
This will be a very interesting build and will be fascinating when you start to run it. Are you working from full size drawings or a published design?
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miken
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Post by miken on Nov 22, 2015 21:03:02 GMT
This will be a very interesting build and will be fascinating when you start to run it. Are you working from full size drawings or a published design? I am working from copies of full size drawings. A clever club member has drawn up the Joy valve gear so it will work in miniature. It was he who designed the Walchearts valve gear for my LB&SCR "J" class tank engine which has proved successful, so Im confident that this will be successful. The boiler will be based on a modified Don Young "Lanky tank" design. MN
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jma1009
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Post by jma1009 on Nov 22, 2015 23:48:04 GMT
hi mike,
wonderful! i remember reading both LBSC's and C.M. Keiller's thoughts on how to improve upon the Webb design.
a very interesting design!
how are you getting on with painting the LBSCR tank? would love to see some further pics of it please!
cheers, julian
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miken
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Post by miken on Nov 23, 2015 11:44:04 GMT
hi mike, how are you getting on with painting the LBSCR tank? would love to see some further pics of it please! cheers, julian Julian, The short answer is ;Very slowly. I have spent the last few months blowing dust and fish-eyes into the paintwork in my draughty garage. Im slowly making progres . will show some pictures when it comes together later.
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miken
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Post by miken on Dec 3, 2015 19:58:39 GMT
Its always exciting the first time you get the wheels onto a chassis. This is only a dry assembly.I still have to finish turn the treads yet and do a bit more cleaning up and deburring. Mike
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miken
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Post by miken on Dec 3, 2015 22:32:06 GMT
No Steve, Many Victorian engines had rectangular section spokes so I thought it might be practical to get them water jetted rather than use castings. I have a copiy of an original drawing for "Teutonic" wheels (which are slightly bigger on the diameter but otherwise similar). A friend drew them up on a computer . The water cutting wasn't particularly cheap but it did produce extremely accurate spoke sections. They are solid. I didn't trouble to fit separate tyres. I turned the fronts and backs to make the spokes tapered on my poor(manual) lathe using a carbide tip tool which was teeth rattlingly loud. The pear shaped boss for the rear wheels was silver soldered on using eayflo no3 which leaves a nice fillet and finished with riffler files ( I new they would be of use one day). I was very concerned that heating up for the silver solder might distort the spokes but it all went well . The balance weights were soft soldered on then finish turned. Here are the blanks for the tender wheels.
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miken
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Post by miken on Dec 21, 2015 21:52:28 GMT
HP Cylinders machined and honed to size. Possibly the most ugly outside cylinders fitted to a loco! They are literally Rectangular iron blocks.
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miken
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Post by miken on Feb 1, 2016 17:16:41 GMT
All LNW engines have push-pull steam valves for the injectors mounted up on the boiler manifold. Does anyone know of a successful design for a compact push-pull valve that I could adapt for this application? The valves are operated by a lever a bit like a whistle valve. I would prefer not to fit the usual type screw down hand wheel type items here as they are in quite a prominent position and very non-prototypical. Thanks Mike
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Post by ejparrott on Feb 1, 2016 20:52:06 GMT
I know it can be done, Glyn Winsall has them on his 5" SR U Mogul
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mbrown
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Post by mbrown on Feb 1, 2016 21:00:15 GMT
Look up the articles in Engineering in Miniature on building a LNWR G Class 0-8-0 - I haven't got my back issues with me at present but I think the design was by "Hotspur" and it came out over many editions a few years ago (maybe someone else can give the exact references) - the design of the boiler fittings included some quite nice pull-out injector valves in the proper LNWR style - they were, I guess, about half way between "model" appearance and "fine scale" but the insides could no doubt be used with slightly more refined external details.
Malcolm
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Haymes
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Post by Haymes on Feb 1, 2016 21:49:37 GMT
Hi Mike, thank you for posting the pictures of your excellent progress. I remember that there are some articles by the late Jim Ewins in the Maidstone Model Engineering Society Newsletters, copies of which have very helpfully been placed online here: www.maidstonemes.co.uk/2101.htmlI have no connection to the MMES but thanks are due to those involved in scanning the newsletters and placing them online. I believe if you have a look at the spring 1985 newsletter there is an article by Jim Ewins on injectors which includes his design of 'pull out' (or rather 'push in') steam valve. Hope this is useful and maybe gives you some ideas although I have no direct experience of this type of valve in miniature. I briefly fired the full size LNWR coal tank last year and found that the injectors took a little getting used to!.. Regards, Carl
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Post by 4fbuilder on Feb 1, 2016 23:39:00 GMT
Hello Mike,
Give Fred Bailey a tinkle, he designed and fitted pull out steam valves on his Lord Nelson, he may well have a drawing or two!
Regards,
Bob
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jma1009
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Post by jma1009 on Feb 2, 2016 5:32:35 GMT
hi mike,
i am afraid my knowledge of LNWR locos is very limited, but i do have drawings of 2 of Webb's patented injectors, stated to be fitted to all his locos. neither have levers for the valves, but 2 handwheels.
if of any interest i can email copies to you.
the Eric Rowbottom injector articles in ME 21st May 1976 include Basil Palmer's Seller's type steam valve operated by a lever (which looks like a whistle lever)
cheers, julian
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miken
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Post by miken on Feb 2, 2016 8:17:42 GMT
An update. I was told that all LNW locos had lever operated push-pull valves. All the Teutonic drawings I have show this. However, after a trawl through all my drawings, I have just realised that the only Dreadnought GA I have clearly shows handwheels as Julian says! This is good enough for me . I will now be fitting conventional screw down valves here. So, thanks for the replies. Sorry I wasted your time. MN
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miken
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Post by miken on Feb 12, 2016 16:33:39 GMT
Made the smoke box and chimney this week. The top photo is actually an "Experiment" class. Slightly different plate work around the LP cylinder due to different position of leaf springs, but I thought it interesting to compare because it is otherwise similar to Dreadnought. Note all the large copper tubes piled up around the front of the loco. All this and more has to be crammed back into the little smokebox somehow (I'm not sure quite how yet).
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