Locomotive Front End Designs

Can a decent front end be made for a two cylinder compound locomotive ?
It is my sincere conviction that the ideal British Pacific will be this one:

https://i.imgur.com/ZQjgKpG.jpg

A 22 inch high presure cylinder on one side,a 33 low pressure inside and some degree of mass balancer on other side.

http://thierry.stora.free.fr/pics/141tc1_1.jpg

If fire is destructed when starting away from stop ,I will have dream of something else.

 

I would guess so, Porta proposed a three cylinder triple expansion locomotive.

 

That's a question worth an answer.... AFAIK, the very last 2-cyl compounds (vonBorries system) operating in these islands were the Bowman Malcolm designed B&NCR 3ft gauge class S (and S1 - just an 'S' stretched by 1ft at the back) 2-4-2t & S2 (one-off 2-4-4t rebuild). The class went extinct in the early/mid 1950's.

 

I would have thought an inside HP and 2 LP outside cyls would be easier to live with and sit well with the loading gauge

 

Yes but the two cylinder scheme can be a little more efficient and maybe enough to compensate for friction in the balancing ding.Piping etc will be simpler.And it is different

 

Being different usually isn't an advantage

 

with two big soft exhausts per revoloution, draughting could be... interesting

 

The balancing of a two-cylinder simple is inherently worse than that of a three-cylinder loco (whether simple or compound), and one with two very different cylinders would seem to be worse still. On the other hand the Smith layout is good for balancing but, with outside LP cylinders that fit the British loading gauge, limits the available TE to about the same as a two-cylinder simple, so one begins to see some sense (though not a lot) in the Webb layout.

 

It has been done before. I mentioned on another thread that I'd like to see Aerolite in action.

 

Hi there

Just a question from me, not meant as any sort of critisism
I wonder why it`s always talks about Lempor exhaust. Why not use Kylchap? Isn`t that good enough? I`m not an technical excpert but I know that Chapelon`s world record compound locomotives 240P had such one.

kind regards,
Knut

 

Exactly and that is why I ask.
The smokebox is quite big on an A2/2 and I wonder how much harm a big volume between low pressure exhaust ports and blast nozzle will do?

 

I am not Webbing here but have one high pressure 22 inch cylinder sitting 37 inches from centerplane and driving first axle inside coupling rods.
Britania has a 20 inch cylinder sitting 40 inches from centerplane and driving outside of coupling rods.
Reciprocating mass will be 121% of Britania.The low pressure piston is bigger but need not be very much more heavy as maxpressure is lower..
Balance trouble is 121% of a Britania.
On the starboard side without cylinder we can use a counterbalancer driven from the front coupling pin like the Nord 2-8-2 tank.
Balance can then be almost what we like or dare.A two cylinder Compound has more even torque than a common four-cylinder simple
Stanier pacifics are next in row for improvement.
According to Cox it had lowest steam consumption of 14.2 lbs per IHPH and best Chapelon was 11.4.My cylinders are bigger and better.

 

Porta published a paper describing how to design a Lempor, and made it freely available. The Kylchap was covered by patents - which have now expired- but there is little or no published information on how to design one, and I think the newer examples are basically copies of the LNER Kylchaps.

 

A couple of billion years of adaptive evolution suggests that may not be the whole story.

 

That's why I said "usually"

 

'Usually' you say? How much more 'usually' does it get than what the entire planet's been doing constantly since at least the end of the Late Heavy Bombardment?

(Image lifted from 'themoviegourmet.com')

........ I can keep this up indefinitely!

 

There have been vastly more cases of when being different has been a disadvantage!

 

..... just not for very long!

As the flight computer on a starliner in a derelict spaceport on a ruined world had it "The statistical probability is that other civilisations will arise and there will again be lemon-soaked paper napkins .... in the meantime, there will be a short delay until our flight inventory is complete .... please return to your seats". (H2G2)

 

I agree with you on that one!

The probability of a random differece being better than the original is pretty small!