P2 Locomotive Company and related matters

AFAIK, superheater element area is calculated on the internal diameter of the tube in terms of heating surface and, when calculating free gas area, the external diameter is used. Does that answer your conundrum? Element length can vary quite a lot, as well. What are you basing length on?

 

Thanks Steve. I'd been using 1" dia for 1.25" OD elements as a compromise. But I guess the wall thickness of the elements would be greater than 1/8". Anyone know the real value please?

Also by coincidence I reached the end of 'under 10 CME's vol2' last night, and in the appendices there's a section on A/S ratios. Apperently the 'S'urface area includes the area of elements ....... so back to the spreadsheet, as my earlier results were based on evaporative area only ......

And finally - does anyone understand the arrangement of the King's boiler? All online sources quote either 16 or 32 flues, but BOTH having 96 elements. How does that work ??? Assuming they are counting each pass as an element, with the 32 flues that would give a 3 pass element, which makes no sense, unless it has a single out-leg and twin returns, or vice versa (and I assume its just plain wrong for a 16 flue design?)

 

RCTS lists the 1951 on King boilers with 32 flue tubes as having 128 elements.

 

Now that makes sense. Never trust the internet!!

 

Phillipson suggests elements of 9 swg and also suggests 1.375/1.5" OD for design purposes. According to Cook, Stanier LMS elements were latterly 1.375" OD and 9 swg (apart from the Coronations). I guess 1/8" is a reasonable guess for your purposes.

No idea about Kings. They're GWR and thus funny by definition.

 

According to Nock in "Stars Castles and Kings" the 2 row superheaters had 1" tubes and the and 4 row superheaters had 1.25" tubes on both Kings and Castles. RCTS doesn't seem to say anything.

 

Here's me thinking the A1 crowd are planning to build a P2 yet we're on about Kings now.

 

Princes, Kings, its all relevant....
Think there might be a few subtle changes to the staying on Meiningen boiler #2 ?

 

Regarding superheaters the LNE carried out a great deal of work particularly on the Gresley Pacifics and RCTS Part 2A is well worth getting hold of. Tests covered a variety of element types in the aim of having a high superheat temperature with minimum pressure drop. Element tubes were 1 1/2" o.d. With a 9swg wall giving an i.d. of 1.212", shown as 1 1/4" on the diagram later 1 7/32". The wall thickness was reduces to 10swg for a period but later reverted to 9swg. The details are interesting but the end result is more important. A pressure drop of only 2 psi was recorded between boiler pressure and steam chest pressure under standard running conditions.
When designing a boiler the small tubes are easy to deal with with the flue tubes and associated superheater elements a little more complicated. The ratio of small to large tubes needs to be considered with due reference to the element type or types selected and the steam temperature being aimed for. Is it that simple? Perhaps not since the gas flow through the various tube types needs to be balanced across the full evaporation range so that the superheat temp remains within acceptable limits.
Questions regarding revisions to the next boiler being built for the A1 Trust might be raised by some with a degree of justification. Perhaps they should try to talk to Alan Haigh and get him to check the drawings over.

 

Haven't seen this mentioned (just in case it already has), but feel they missed out badly with the proposed name for 2007 bearing in mind the P2s Scottish connections. They could have combined the two with "Bonnie Prince Charlie".

 

Thanks - I had assumed 1.25" as that's what Stanier used on the LMS.

 

I put that forward, but I'm sure they know what they're doing - there'll always be a PoW after Charles has gone.

 

And of course Bonnie Prince Charlie sought to usurp the British throne and has no real connection with our Prince Charles.

 

Never let the truth get in the way of a good loco name eh?

 

See what you can make from this.
Cheers

 

Thanks, that's really helpful. Shows the distance between the element tip and the firebox tube plate - so my needing to reduce element length to get the super-heater area to agree with published data was reasonable. Also confirms tube diameters and wall thicknesses. Interestingly it appears the each element is a pair of 2 pass tubes, rather than the single 4 pass element that most companies used latterly to get maximum superheat.

 

They can't name the P2 after Scottish connections.. Imagine how funding would dry up if the Scots vote yes in 2014.
Even worse, imagine if the Scots tried to "take it as a possession".

 

I can't see that happening. However, if the English get to vote on the referendum as well, that's a different matter!

 

If we had our own referendum, "do we want to keep Jockland in the union?" I for one would vote no - ANYTHING to get that smug git Alex Salmond (Salmand?) off me TV screen/out of the media!

But then again it probably wouldn't work given how many of the natives live South of Hadrian's wall (they obviously know they're onto a good thing!), unless they are banned from voting...................................

 

A series of roadshows have been announced for No. 2007, including two in Scotland! But not one in Doncaster.......

All presentations will start at 11.00am with a second presentation at 2.00pm if numbers require it. More details and bookings on the P2 website.

8th March – London
Venue: The Drawing Room
Landmark Hotel (former British Rail HQ), 222 Marylebone Road, London, NW1 6JQ

22nd March – York
Venue: Duchess of Hamilton Suite
National Railway Museum, Leeman Road, York, YO26 4XJ

5th April – Darlington
Venue: The Studio Room
The Dolphin Centre, Horse Market, Darlington, County Durham DL1 5RP

26th April – Edinburgh
Venue: Beauly or Esk Suite
The Balmoral, 1 Princes Street, Edinburgh, EH2 2EQ

17th May – Aberdeen
Venue: School of Engineering, Garthdee Campus
Robert Gordon University

Foxy