RMweb Premium Andy Keane Posted February 22 RMweb Premium Share Posted February 22 28 minutes ago, The Johnster said: That doesn't quite make sense, Andy So I now learn - it seems the chuff rate as shipped on this latest series of Dapol Moguls is simply not right for the gearing and motor they come with. Keith in their tech department has helped me sort this out. I had wrongly assumed that it was 4 cyl versus 2 cyl thing as I was thinking how petrol engines are timed - I now know better. I think it is simply something they overlooked and when Keith saw my video he realised it was not correctly matched. Hence the change to CV 267 from 29 to 58. 2 1 Link to post Share on other sites More sharing options...
RMweb Premium Andy Keane Posted February 22 RMweb Premium Share Posted February 22 Keith at Dapol is happy for me to share onwards the info on the Mogul sound project to RMwebbers. There is a word file full of screen shots from his decoder programmer and a more general spreadsheet to help explain the various CVs they use. Enjoy! Dapol GWR 43xx Mogul sound project CV list.docx Useful Zimo CVs for distribution Mogul.xls 1 4 Link to post Share on other sites More sharing options...
Steamport Southport Posted February 22 Share Posted February 22 1 hour ago, The Johnster said: GWR locos were never 'modernised' with air brake fitttings by the GW or BR; in fact the Westinghouse Air Brake fittings were removed from absorbed/constituent locos like Barry Railways after the grouping. Some GW locos have recieved air brake fittings in preservation in order to run with air-braked main line stock, but never in pre-preservation service. The Vale of Rheidol has converted to air brake throughout and it's locos have Westinghouse air brake fittings. Air brakes on steam locos are easily spotted as they carry vertically mounted Westinghouse air pumps to maintain the brake pressure; this is the gubbins usually situated on the side of the smokebox that makes a pppphhh ppphhh sound as it rebuilds air pressure, sometimes when the loco is stationary. Another version was found on emu Southern and LT stock, and went 'chunka-chunka-chunka', a noise which no doubt still haunts the dreams of Londoners over about 40 years old... The vacuum brake version of this is the vacuum pump, and on GW outside-cyldinderd locos it was mounted horizontally on the rh side of the loco just above the cylinder, and driven by a motion-actuated piston. It operated continuously when the loco was in moton, and the t-t-t twice per driving wheel revolution was continuous as well, but obviously easier to hear when the engine is not chuffing, such as when coasting downhill, hence 'on the overrun when the chuffing dies back'. It is a very characteristic GW sound, and was quite noticeable in reality. The t-t-t became more a ts-ts-ts on high-mileage engines due for overhaul, accompanied by a small amout of steam leakage. I can't comment on how realistic the Dapol noise is, as I can't afford DCC. I make my own chuff chuff and t-t-t noises, sometimes out loud. The Squeeze is fully aware that I'm bonkers and ignores me. Best not mention the Westinghouse fitted Moguls and Bulldogs then..... 😉 https://www.facebook.com/DidcotRailwayCentre/photos/a.210517012308528/4489311107762409/?type=3 http://www.gwr.org.uk/no440s.html Jason 3 2 Link to post Share on other sites More sharing options...
RMweb Gold 57xx Posted February 22 RMweb Gold Share Posted February 22 3 hours ago, Andy Keane said: I am confused - I thought with two extra cylinders they would be timed to exhaust in between the other two and, all being double acting, I expected a two cylinder engine to give four beats per revolution and a four cylinder engine to give eight? Does this mean that the timing is set up so that on four cylinders the pistons are in pairs like on a four cylinder four-stroke petrol engine? Clearly I have much to learn! If you're thinking IC engines, Steam engines are neither 4 strokes or 2 strokes, they are in fact 1 strokes! Steam is injected either side of the piston to move it in each direction. 1 Link to post Share on other sites More sharing options...
RMweb Premium Andy Keane Posted February 22 RMweb Premium Share Posted February 22 (edited) 6 minutes ago, 57xx said: If you're thinking IC engines, Steam engines are neither 4 strokes or 2 strokes, they are in fact 1 strokes! Steam is injected either side of the piston to move it in each direction. That bit I did know. I was more thinking about evening out the thrust. On petrol engines the aim is to even out the pulses from firing which are much sharper than steam of course, so on an eight cylinder engine one tries to time them evenly with things like 90 degree V8s. On five cyl petrol engines they also have a curious spacing between bores to balance out the rock as well as the pulses. The most extreme were the old Daimler double six straight 12 engines. Edited February 22 by Andy Keane 1 1 Link to post Share on other sites More sharing options...
RMweb Gold 57xx Posted February 22 RMweb Gold Share Posted February 22 2 minutes ago, Andy Keane said: That bit I did know. I was more thinking about evening out the thrust. On petrol engines the aim is to even out the pulses from firing which are much sharper than steam of course, so on an eight cylinder engine one tries to time them evenly with things like 90 degree V8s. On five cyl petrol engines they also have a curious spacing between bores to balance out the rock as well as the pulses. Yes, triples with 120* cranks are notoriously smooth. Parallel twins usually have a bad rocking couples. Even firing orders are not always desired, think V4 "big bang" 2 strokes. Link to post Share on other sites More sharing options...
RMweb Premium Andy Keane Posted February 22 RMweb Premium Share Posted February 22 I am also going to replace the Mogul's plastic coal load with a sheet of lead covered in the real stuff (happily the plastic coal is not glued in - a nice touch from Dapol). Since I don't have a turntable at Helston I need my tenders to run well when being propelled backwards over the points and some weight always helps - it should also help keep good electric contact on the tender wheels to the track. 3 Link to post Share on other sites More sharing options...
RMweb Gold Harlequin Posted February 22 RMweb Gold Share Posted February 22 (edited) 32 minutes ago, Andy Keane said: I am also going to replace the Mogul's plastic coal load with a sheet of lead covered in the real stuff (happily the plastic coal is not glued in - a nice touch from Dapol). Since I don't have a turntable at Helston I need my tenders to run well when being propelled backwards over the points and some weight always helps - it should also help keep good electric contact on the tender wheels to the track. The tender in the batch1 moguls had a big diecast block in them with a well to hold a 40*20mm speaker so I'm a bit surprised you think it needs extra weight. Is there a speaker in the tender? I hope so! If so, you could make sure the diaphragm is facing upwards and do the mesh coal load thing. Edited February 22 by Harlequin Link to post Share on other sites More sharing options...
RMweb Gold The Johnster Posted February 23 RMweb Gold Share Posted February 23 There are single-cylinder steam engines, which have to be set in motion and kept in motion by a flywheel to avoid the piston coming to rest ‘top or bottom dead centre’ of it’s stroke, and, with the centre of the piston, and that of the connecting rod in a straight line, and the crank bearing unable to be moved because the conrod has to apply pressure to the side of the crank to set it in motion. This is why large steam engines and all railway steam engines have more than one cylinder, and why single-cylinder motorcycles are kick-started. Multi-cylinder engines of all types offer smoother delivery of power because the tdc/bdc tight spot, which is the main cause of the wear to big end bearings and the ‘clonk’ you hear when high-mileage engines are coasting, is ‘shared’ among the ciders and there is always at least one other cylinder to move the main crank axle when one is at tdc/bdc. Top and bottom in this sense refers to the original pumping engines and is of course suitable terminology for internal combustion engines but the cylinders are mounted horizontally on steam railway locomotives. The terms are still used. all the same, top dead centre being with the piston at the furthest forward part of it’s stroke and bottom dead centre being when it is at the rearmost part. In railway use, especially in the UK becsuse of the limited loading gauge, multi/cylinders are also used to control the loco’s overall width, as by adding one or two cylinders between the frames in addition to two outside them, the total capacity of the cylinders can be increased without making the outside cylinders wider. No such thing as a free lunch, and the down side is that the loco takes longer to prepare and has awkward-to-reach oiling points, and the valve gear is difficult to set up at it’s most efficient. But where high-revenue traffic is being catered for, such as with express passenger engines, it was considered worth the bother, especially in pre-war days when shed labour was plentiful. 1 Link to post Share on other sites More sharing options...
Coppercap Posted February 23 Share Posted February 23 16 minutes ago, The Johnster said: and why single-cylinder motorcycles are kick-started. Things have moved on a bit since the 1950s - virtually all single-cylinder motorcycles these days have an electric starter, without even a kick-starter as a back-up for when the battery's flat! 1 Link to post Share on other sites More sharing options...
RMweb Gold The Johnster Posted February 23 RMweb Gold Share Posted February 23 I know. Link to post Share on other sites More sharing options...
RMweb Premium Andy Keane Posted February 23 RMweb Premium Share Posted February 23 10 hours ago, Harlequin said: Is there a speaker in the tender? Yes the factory sound fit does include a tender speaker but when you remove the coal load you find a completely sealed tender floor, so not much comes that way. I think the hope is the loco speaker does the higher notes with just the lower frequency stuff from the tender. I could I suppose drill some holes and then fit a grill with coal. I will investigate. 1 Link to post Share on other sites More sharing options...
RMweb Premium Andy Keane Posted February 23 RMweb Premium Share Posted February 23 4 hours ago, Andy Keane said: Yes the factory sound fit does include a tender speaker but when you remove the coal load you find a completely sealed tender floor, so not much comes that way. I think the hope is the loco speaker does the higher notes with just the lower frequency stuff from the tender. I could I suppose drill some holes and then fit a grill with coal. I will investigate. I have now pulled the tender apart. There is a big trad oval speaker fitted, but it faces downwards through an opening to the axle area. Its back is fully enclosed so little point in opening up above. I could rotate it but then the lugs would need cutting off the speaker, so I will leave well alone. It is also offset to the rear of the tender so some lead at the front under the coal will help. 1 Link to post Share on other sites More sharing options...
RMweb Premium Andy Keane Posted February 23 RMweb Premium Share Posted February 23 I have now swapped over the coal load, added the lead, a crew and toned down the footplate colour a bit. Final stage will be a full weathering. 10 Link to post Share on other sites More sharing options...
RMweb Gold sjrixon Posted February 24 RMweb Gold Share Posted February 24 Nice work Andy.. I find I need to own and run them for about a year before I start taking them apart! 1 1 Link to post Share on other sites More sharing options...
RMweb Premium Popular Post Andy Keane Posted February 24 RMweb Premium Popular Post Share Posted February 24 Now suitably grubby: 20 1 Link to post Share on other sites More sharing options...
RMweb Premium Andy Keane Posted February 26 RMweb Premium Share Posted February 26 Minor question for those in the know - why were the chimney caps made of copper and not brass? Link to post Share on other sites More sharing options...
Steamport Southport Posted February 26 Share Posted February 26 16 minutes ago, Andy Keane said: Minor question for those in the know - why were the chimney caps made of copper and not brass? It's definitely been covered before. Something to do with heat ISTR. Jason Link to post Share on other sites More sharing options...
RMweb Premium Hal Nail Posted February 26 RMweb Premium Share Posted February 26 1 hour ago, Andy Keane said: Minor question for those in the know - why were the chimney caps made of copper and not brass? 1 Link to post Share on other sites More sharing options...
RMweb Gold sjrixon Posted February 27 RMweb Gold Share Posted February 27 (edited) Mine just arrived.... I need to review Any's posts, as my chuff rate is very out! I also felt like the top speed is quite low, the chuff is going crazy, while the loco is hardly moving! I'll give it a short run in before playing the CVs.. It's also quite loud pulling away! Much more than the Accurascale Manor. Nice looking loco in the GWR green and full lining though. Edited February 27 by sjrixon 1 Link to post Share on other sites More sharing options...
RMweb Gold sjrixon Posted February 27 RMweb Gold Share Posted February 27 (edited) 20240227_131627.mp4 Showing the odd chuff rate.. - I'll tweak the CV later.. Edited February 27 by sjrixon 4 Link to post Share on other sites More sharing options...
RMweb Gold franciswilliamwebb Posted February 27 RMweb Gold Share Posted February 27 The model seems to chuff about twice as fast as it should? 6 1 1 Link to post Share on other sites More sharing options...
Miss Prism Posted February 27 Share Posted February 27 Yes, the vacuum pump sound is too 'clicky'. Link to post Share on other sites More sharing options...
Steamport Southport Posted February 27 Share Posted February 27 3 minutes ago, franciswilliamwebb said: The model seems to chuff about twice as fast as it should? Ten years ago! EEK! Jason 2 Link to post Share on other sites More sharing options...
Miss Prism Posted February 27 Share Posted February 27 Great video. Magnificent scenery! 2 Link to post Share on other sites More sharing options...
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