BR Standard class 6 No. 72010 'Hengist' and Clan Discussion Thread

That was one of the most challenging workings on the SW mainline as Britains most multi sectioned train, I think the first coaches were detached at Sidmouth Junction for Sidmouth. Always a Merchant Navy working, would need double headed Clans to keep time. Light Pacifics worked the much reduced train west from Exeter where it split for Plymouth and the North Devon destinations

 

I don't think anyone is suggesting that the Clans would have been Merchant Navy replacements. Seems far more likely to me that - had they arrived in the south in large numbers - that they would have replaced the King Arthurs, which, by the 1950s, were 30-odd years old and pretty long in the tooth for front line express passenger locos. Presumably, the spread of electrification through Kent and cascading of other locos meant that there was simply no need.

Tom

 

Much as i think that 72010 Hengist will be a capable and sound engine . it wont match upto a wc/bb,definitely not a MN
The plan to build 100+ clans dates back to when it was conceived as a class 5 pacific i suspect. They would have been built instead of not as well as the Standard 5's. Bet your ass that they would have got a proper looking at at Rugby with that many...

 

21C154 on the 'Arrer in 1947, somewhat before the Brits arrived let alone went and presumably also before the tally of Pullmans was reduced.

 

A substitute engine for the regular MN I would think, note that it's not fitted with brackets and therefore doesn't carry the big arrow on the side of the casing.

 

Not suggesting the Light Pacifics were the dominant motive power on the early pre war 'Arrers but I have seen pictures of them working it during that period.

 

This is what I thought too

 

Why any pacific was considered for the S&D is a mystery. The Standard 5s had 1.8tons more adhesive weight and were less likely to slip on such a steeply graded but low speed route. When the Bullieds were rebuilt the adhesion factor was improved but by then there was little interest in using anything other than Stanier of Standard 5s.

 

"pre war 'Arrers" ?

 

I guess it will remain a mystery as to where these modified 'Clan' Pacific's were going to be based and used. It will be perhaps more interesting to know where the new one is going to be used, but we are a little early for that discussion. Not that that fact will prevent debate on NP.

 

Oops! Got me prefixes wrong. I meant of course post war 'Arrers.

 

It dropped a coach off the back at Salisbury which was attached to the following stopper. I'm not sure if the up service had coach added at Salisbury or not.

 

More impressive pieces of metal produced and available to view at http://www.theclanproject.org/news

Looks like the exhaust spider pattern needs replacing... is this the same as on a brit ? be nice and open if it is so put a Kordina/Gauss wall in it - you know you want to....

 

A Kordina device is a means of reducing the effect of the exhaust steam from one cylinder flowing into
the other cylinder, causing an increase in backpressure on that cylinder and reducing its power output.
It is formed by casting into the exhaust steam discharge passages a narrowing whose area is equal to
the area of the blast nozzle tip area. This restriction reduces the backflow into the cylinder.
The BR6 uses the same piston valves, piston valve liners and exhaust spider as the BR7, so an
indicator card from a BR7 will be similar to what could be expected for a BR6.

There is an indicator card taken from BR7 No 70025, (239 psi boiler pressure, 231 psi steamchest
pressure, 30% cut off, 40 mph, 20940 lb/hr of steam 1509ihp). The indicator card is from the archives
of the National Railway Museum. There is evidence of a small effect, but insufficient to warrant
adoption of a Kordina for 72010.

The above is a quote from the work we have had done on the front end design in conjunction with ASTT. The conclusion was that there is no benefit to be gained from the fitting of a Kordina device, but other modifications were worthwhile.

Details will be released at some point, but for the moment remain confidential.

 

A Kordina device is a means of reducing the effect of the exhaust steam from one cylinder flowing into
the other cylinder, causing an increase in backpressure on that cylinder and reducing its power output.
It is formed by casting into the exhaust steam discharge passages a narrowing whose area is equal to
the area of the blast nozzle tip area. This restriction reduces the backflow into the cylinder.
The BR6 uses the same piston valves, piston valve liners and exhaust spider as the BR7, so an
indicator card from a BR7 will be similar to what could be expected for a BR6.

There is an indicator card taken from BR7 No 70025 (239 psi boiler pressure, 231 psi steamchest
pressure, 30% cut off, 40 mph, 20940 lb/hr of steam 1509ihp). The indicator card is from the archives
of the National Railway Museum. There is evidence of a small effect, but insufficient to warrant
adoption of a Kordina for 72010...

In other words there is no benefit to be gained from adoption of a Kordina, so it will not be fitted.

 

Could you by any chance mean Goss wall?
In the Engineer Jan 20, 1888 page 46, which is available on the web, there is a full drawing of the original Kordina device.
http://www.gracesguide.co.uk/images/1/13/Er18880120.pdf
Kind regards
Jos Koopmans

 

Right you are Mr K.
Lovely attachment
Sorry Bob couldn't resist and I heard you the first time !. But as the furniture on Hengist either side of the blast pipe is possibly not going to be the same as a Britannia ( Considerations given to piston valves and cylinder design one side, and blast pipe chimney at the other) then the Britannia card becomes less relevant ? does it not? and the Exhaust spider design sweeps up so beautifully into this proposed central partition it almost begs to be there...
Speaking of which, have Sheff and co. come up with anything else on the Clan re-realisation front...? Feel free to PM.

 

As I read the report all the possibilities of redrafting were considered, including those made by changes to the piston valves, lubrication changes to the cylinders,, etc. The conclusion is still the same - it will not improve the performance of the locomotive to fit a Kordina device.

 

As long as the plan is to stick with the enhanced single chimney and not go the extra mile for a double you're probably right enough.

 

No advantage gained by a double chimney. It was looked at, but it is unnecessary. The mock up made Hengist look like a baby 'Duke rather than a baby 'Brit. Very strange...