BryceGTX wrote:...
Focusing on Americans is counter productive to any open discussion. It seems is clear from your posts that you do not like any of the American researchers Young and Goss. I see this as a bad case of not invented here syndrome. Perhaps we can stick with the facts.
Bryce
On the contrary, I have to use the research of Goss and Young and for that matter Buckingham all the time to argument that some people are on the wrong track!
Examples? Goss research on petticoats and his explanation of the induced stack flow. Young proved the equivalence of a double length chimney and a normal length chimney with four orifices and so on!
Kind regards
Jos Koopmans
The GWR used Goss in Churchward's time on the GWR post 1904 with significant experimentation and fine tuning for a set of standard smokebox draughting arrangements.
Sam Ell, perhaps the cleverest man employed by the old GWR apart from Willie Pearce of valve gear fame, knew of Young's research and papers.
When you have read in detail the UK BR test reports of various locos in fullsize for draughting modifications under Sam Ell in the late 1940s and 1950s you might reconsider your views, and agree with Jos Koopmans. In the UK we have quite a different view of running miniature locos to what appears to be the norm in the USA. Many UK type designs have peculiar design problems for draughting both in fullsize and miniature due to the restricted loading gauge and big locos to the limit of the loading gauge with short (too short) large diameter chimneys.
Jos's work on UK locos both miniature and fullsize has been invaluable and is highly regarded.
None of this helps Fred! However I think Fred has done a very good job with his last couple of drawings. I would like to see the internal sleeve taken up higher to accord with Jos's 1:12 divergent taper above the choke. This isnt easy to make and realise Fred has compromised but the compromise is a great improvement on the original!
Julian, I have that tapered iron casting I pictured in another post. It could be cut down and fitted inside the Hunslet stack along with the chunk of steel made into a petticoat.
The green lines are a 10 deg. cone that hits the wall of the stack just above the taper part. The choke would be 1.825", nozzle .438" dia.
Your alteration looks very good and an improvement on the two previous drawings. As long as you keep to the Jos Koopmans proportions I detailed a week or so ago for distance to choke from blast nozzle top, and diameter of choke, and with an enlarged blast nozzle, you should have a significant improvement in steaming of the loco and less steam required for the cylinders due to reduced back pressure. This is a 'gain gain' situation with good smokebox draughting. The exhaust might be nearly inaudible but that doesnt bother us in the UK and Europe!!
JJG Koopmans wrote:
You should use a better argument, since when is a supercritical superheated supersonic jet without any entrainment normative for our problem?
Kind regards
Jos Koopmans
It is not at all normative. Rather the 10 degree angle represents the least angle the steam can make. So any stack design must adhere to it. Perhaps I should remind you of the 1/6 thread that went on for years and you never presented a legitimate argument why it works!!! The basis of it working is the 10 degree angle.
Bryce
Last edited by BryceGTX on Wed Aug 03, 2016 7:43 pm, edited 1 time in total.
I am not dismissing anyone. Least of all my European colleagues. It was Jos that mocked his American colleagues. Perhaps you should reread his post. On the other hand Youngs research directly disagrees with Jos research. Jos often dismisses Youngs research based on that.
In another thread, we proved Jos assumptions were incorrect and Young was correct.
Bryce
Last edited by BryceGTX on Wed Aug 03, 2016 8:04 pm, edited 2 times in total.
Fred_V wrote:Julian, I have that tapered iron casting I pictured in another post. It could be cut down and fitted inside the Hunslet stack along with the chunk of steel made into a petticoat.
The green lines are a 10 deg. cone that hits the wall of the stack just above the taper part. The choke would be 1.825", nozzle .438" dia.
Hi Fred, it might be instructive to place the 1/3 cone in the drawing. If the stack base diameter is decreased, you will have to check if the blast nozzle needs to rise.
Thanks,
Bryce
JJG Koopmans wrote:
You should use a better argument, since when is a supercritical superheated supersonic jet without any entrainment normative for our problem?
Kind regards
Jos Koopmans
It is not at all normative. Rather the 10 degree angle represents the least angle the steam can make. So any stack design must adhere to it. Perhaps I should remind you of the 1/6 thread that went on for years and you never presented a legitimate argument why it works!!! The basis of it working is the 10 degree angle.
Bryce
I am not dismissing anyone. Least of all my European colleagues. It was Jos that mocked his American colleagues. Perhaps you should reread his post. On the other hand Youngs research directly disagrees with Jos research. Jos often dismisses Youngs research based on that.
In another thread, we proved Jos assumptions were incorrect and Young was correct.
Bryce
You better do not spread misinformation. I totally accept Young's tests, however I have second thoughts about his calculations and explanations.
Fred_V wrote:Julian, I have that tapered iron casting I pictured in another post. It could be cut down and fitted inside the Hunslet stack along with the chunk of steel made into a petticoat.
The green lines are a 10 deg. cone that hits the wall of the stack just above the taper part. The choke would be 1.825", nozzle .438" dia.
Hi Fred, it might be instructive to place the 1/3 cone in the drawing. If the stack base diameter is decreased, you will have to check if the blast nozzle needs to rise.
Thanks,
Bryce
The 1:3 cone hits just above the choke. The taper of stack liner above the petticoat is 1:12.
You really ought to read all the available UK Rugby Test reports of British Railways of the late 1940s and 1950s. These were mostly draughting tests under the watch of Sam Ell.
These were tests on fullsize locos.
They surpass Goss and Young in the USA by a considerable margin.
If you have not read the Rugby Test reports (most are available online now) I would humbly suggest you do so, and reflect.
They require modification in miniature which Jos Koopmans has done, and he has also reformulated the Ell mathematics and formulae into something that can be easily understood and applied.
Personally, I would regard Jos's work as one of the most significant achievements in miniature locomotive design in the last 60 years.
It's significance and application has been used in the UK and Europe for 10 years. I do not quite understand why our USA cousins do not embrace it and use it!
I think the main problem you have, Bryce, is that you have never built a miniature loco, and argue things to the limit of toleration from an armchair! Those of us who get covered in smuts and oil deserve a bit of tolerance from you!
I have redraughted miniature locomotive smokebox designs applying Jos's work all over the world from Australia to South Africa and also for a few friends building UK designs in USA. Plus many in the UK.
Semantic arguing gets us all no where.
Read all about Sam Ell then come back to us with either a demolition of his thesis and principles, or agree with us in the UK and Europe!
JJG Koopmans wrote:
You should use a better argument, since when is a supercritical superheated supersonic jet without any entrainment normative for our problem?
Kind regards
Jos Koopmans
It is not at all normative. Rather the 10 degree angle represents the least angle the steam can make. So any stack design must adhere to it. Perhaps I should remind you of the 1/6 thread that went on for years and you never presented a legitimate argument why it works!!! The basis of it working is the 10 degree angle.
Bryce
Clearly the problem with this discussion is it is not specifically steam.
The 1/6, 1/3 design process provides a blast angle variance of 10 to 20 degrees. Half angle 5 to 10. So using this process recognizes that the blast angle varys from a maximum of 20 degrees to a minimum of 10 degrees. We cannot ignore either angle.
Bryce
Last edited by BryceGTX on Fri Aug 05, 2016 10:13 pm, edited 3 times in total.
