John Hill did a rerun of a draughting in Model Engineer some time last year. Changing the 17 degrees to 16 from the original done about 1985 I noted. 17 seems to crop up several times as in 17 to 1 in the ratio of air to petrol. One thing I have noted over the years are the comments from Drivers complaining of lack of performance after several hours especially with an overactive lubricator. At Reading we run through a wood, so if I am let a drive a twig and a scrape of the interior of the chimney sends her back to normality. David and Lily. Just back from a day at Andover track.
Hey Tom love the work on the nozzle , this would help me out so much with my locomotive build and when i get to the stage of doing the Blast pipe and Stack. Cant wait to see what else you do with the loco build. Kevin
I have got rosebuds in my other locos, with great success, however on this loco to swap the grate would be a boiler off as it is fixed in place with a hinged centre section. If the boiler is ever off for any reason then I may well switch it.
Tom, just wondering how you calculated the choke diameter and is there any reason why the height from blast nozzle to the choke is x7 of blast nozzle diameter, as I've read some people do x12. Any advice is much appreciated.
To be honest I was just following the research done by someone else, and that’s what the article I’ve been working from suggests. It’s worked well on all my locos so far, so I tend to stick with it.
Have you got access to a copy of Martin Evans book on building model steam engines. It gives an angle to the bottom of the stack AND an angle to the top of the stack. From memory the entry radius is not as large. I'll send a copy.
John Hill did a rerun of a draughting in Model Engineer some time last year. Changing the 17 degrees to 16 from the original done about 1985 I noted. 17 seems to crop up several times as in 17 to 1 in the ratio of air to petrol. One thing I have noted over the years are the comments from Drivers complaining of lack of performance after several hours especially with an overactive lubricator. At Reading we run through a wood, so if I am let a drive a twig and a scrape of the interior of the chimney sends her back to normality. David and Lily. Just back from a day at Andover track.
Hey Tom love the work on the nozzle , this would help me out so much with my locomotive build and when i get to the stage of doing the Blast pipe and Stack. Cant wait to see what else you do with the loco build. Kevin
Good stuff. I am pleased that you double checked tapers. Doesn’t take much to improve drafting if you know what to do!
Good result so far tom steaming a lot better good improvement made
Where can I read about this science please Tom ??
Have you thought of trying a rosebud grate? It is something I fancy trying but haven't got round to it yet.
I have got rosebuds in my other locos, with great success, however on this loco to swap the grate would be a boiler off as it is fixed in place with a hinged centre section. If the boiler is ever off for any reason then I may well switch it.
Tom, just wondering how you calculated the choke diameter and is there any reason why the height from blast nozzle to the choke is x7 of blast nozzle diameter, as I've read some people do x12. Any advice is much appreciated.
To be honest I was just following the research done by someone else, and that’s what the article I’ve been working from suggests. It’s worked well on all my locos so far, so I tend to stick with it.
Have you got access to a copy of Martin Evans book on building model steam engines. It gives an angle to the bottom of the stack AND an angle to the top of the stack. From memory the entry radius is not as large. I'll send a copy.
I’ve had a look through my shelf, I have his book on valve gears, but not his building model steam engines book.
Thanks.
@@TomsWorkshop42 It's on it's way via Martin.
Thank you so much 🙏.