Niels

6 hours ago, Tony Wright said:

 

And, anyway, who's going to want what I've got after I've popped off? Blokes of my age - already past their Biblical three score years and ten, and counting. A rapidly diminishing potential purchasing pool!  

 

Regards,

 

Tony. 

I for one would like one of Your countless A2/2s with wedge cab.

Running ability does not matter.

Modify one side a little and take it along and show mr Thompson what he should have done and ask why he did not.

There must be an interesting story there.

In 1923-5 all Raven  front wheel driven Pacifics  had new crankshafts .

Ravens son died in WW1.

Raven out in the cold.

When Thompson had to do something to the crank and rail-breaking P2s he goofed,even if Ravens frontwheel B16 was a succes.

Strange.

2 hours ago, RLBH said:

Looking at it from a slightly different point of view - a steam locomotive is a means of turning coal into power at the wheels. Provided that the designer did his job right (and I suspect it always was a man), and therefore all the gubbins between the fire and the wheels can cope with the energy produced, a bigger fire will result in more power and therefore a locomotive that can pull a bigger, or faster, train.

 

The 9F has a 40 square foot grate, a Thompson Pacific has a 50 square foot grate. Since we can assume that both Thompson and Riddles were basically competent engineers producing the best locomotives they could, whatever one's quibbles with particular decisions, it stands to reason that an A2/3 should be able to produce about 25% more power than a 9F. Provided all other things are equal, of course. LMS power classification worked more-or-less on that basis, and the BR passenger power classification also did so to a lesser extent - the BR formula tried to ensure proper proportions of boiler, cylinder, and grate, but basically two-thirds of it comes from being able to burn enough coal.

 

It's also possible to come up with a figure based on cylinder dimensions, which gives the A2/3 about 35% more power. Even the V2 has about 13% more than a 9F, despite its' lower starting tractive effort. I've not figured out the formula for boiler power yet, but good design practice was for the boiler to be capable of generating more steam than the cylinders could use.

 

Interestingly, and surprising nobody, there's very little in it between a Coronation, a Peppercorn A2, and a Merchant Navy - a King or Princess is about 100hp less, and an A4 about 200hp less. The P2s knock them all for six, of course . Seriously impressive machines, and I look forward to seeing a 12":1 foot model of one running on the main line in a few years.

As I understand it ,it was a long long journey with only a single unionized fireman at a time.

That is less than 3000lbs coal per hour.

The A2/2 advantage was maybe that the  grate did not go haywire so soon.

In the calculation of starting/dead slow effort it is also nessecary  to include  wheel diameter and pressure.

The  important thing for haulage is adhessive mass; 66 tons for the A2/2 and V2 and 77 for 9F

The downside to a big grate is that it wastes  more coal all the time with fire.

4 hours ago, MikeTrice said:

Like these?

 

 Exactly.

Thank You.

My next step is to make a 4-8-0 three cylinder compound version with nicer footplating

3 hours ago, APOLLO said:

. A full head of steam for Boars head bank immediately ahead. As good as a Duchess ?

 

 

Brit15

 A duchess is 5% heavier and uses roughly 10% more steam and coal for making same number of horses

23 hours ago, MikeTrice said:

My most complicated 3D model to date was printed for the first time yesterday and is very much a work in progress:

 

 

Some thinks that LNER cabs and round top boilers look better  than  the LMS things.

If  LNER people had got the top jobs instead of Riddles /Cox  a 9F would have looked different.

Does it sound to obscene to put this nice 3D printed Cab/Boiler alongside a 9F model (if You have one of course) and make a picture?

I have bought a Dapol Evening star and a Bachmann V2 boilerCab so I can make the scheme myself.

Best British locomotive coming :

Three cylinder Compound 4-8-0 (improved 9F) with Cab and boiler from LNER V2

Money makes the world go round

33 minutes ago, MikeTrice said:

My most complicated 3D model to date was printed for the first time yesterday and is very much a work in progress:

 

 

 

Why bother with the new Bachmann V2 announced? Good question. Reasons have all been given by Tony and others before me: cost; satisfaction; self-sufficiency and most importantly I wanted to prove I could do it.

 

 

 Do You plan to supply wedge fronted cabs to modify the new Hornby A2/2s?

 Hornby will not model the real Thompson shape as I understand the anouncement.

To follow up on posting above

Thomson could also have ordered :

Two simple outside and some kind of extra balancing between frames

Two inside like B12 and some outside counterbalancing

Three cylinder compound ala Sauvage /Smith

One low pressure between frames and one high pressure on starboard side and a counter balancer on other outside.

According to a German 1942 source, fuel for same work will be from 114 for a three cylinder simple to 100 for a two cylinder compound

It is my hope to be able to convince mr Thompson that his scheme can be improved somewhat.

I cannot afford four full size A2/(4 , 5, 6 and 7) but two or three modified Hornbys is possible.

Thank You Hornby.

On 09/01/2020 at 14:30, 34theletterbetweenB&D said:

And when that was done, the Belpaire firebox was proven to be a vanity: it did not outperform the round top. (In fact the reverse, it was inferior.) What was not done - for obvious reasons, as it was pointless - was to test the round top with the superior fuel. But coal will burn on any suitable grate, and the higher energy output of a superior coal will benefit the performance of any competently designed boiler. It's very simple to understand.

I have looked up the  (BR Rugby) boiler efficiency tests of Britannia/9F (Belpaire) and V2 (same boiler as A4) at 3000lbs Blidworth coal per hour.

To  my eyes they are all 73%.

If we asume that mass of Belpaires are higher than round tops it is vanity.

B1,Halls and Black Fives had also identical boiler efficiencies if I remember OK.

I do not have the Hall and Black Five reports anymore.

Some good Pacifics had round firebox covers.

History has proved  that if You must have more than two cylinders for mechanical balance at speed or gauge, three is a good number and inside cylinder drive to front big wheel shaft is good.

You were getting very close Thompson.

It is therefore strange that he opted for having outside cylinders hanging in the middle of nowhere as he  could not reuse the Darlington cast monoblock cylinders from the P2 for clearence reasons.

We can with the benefit of hindsigth and Hornbys phantastic gift to humanty  help him.

It is my ambition   to show mr Thompson how he should have rebuilt the 2-8-2 thing of mr Gresley that by the way had better been a 4-8-0 based on a  2-10-0 with round top boiler.

Full size is out of question going through the heavenly doors so 1:76 will have to do.

I am therefore looking for a model of  A2/2 and Evenings star that can serve.

Asking mr Wright to modify will probably not work and funds are not unlimited either.

There is a DJH kit of A2/2 on ebay but  question is how long before the Hornby thing is for sale and what would be easier to modify?

Will the top of the model (round topped boiler)  be sold separately?

23 hours ago, RedGemAlchemist said:

Speaking of beasts, here's a 4-10-2 monster I found on YouTube:

 

Good try

2-12-4 tank with long life

7 hours ago, jrg1 said:

In all the posts regarding the merits of heavy goods locomotives, why has there been no mention of the GWR 47xx class?  

Fast, powerful, versatile and at home on heavy mixed traffic-and only nine were ever built.

Around ww1 civil engineers began to understand and could calculate the rail disturbing forces from steam locomotives.

The 47xx had ca nine tons on each driver.

It had very short connecting rod driving second driver.

Pulling hard forward this means that the driven wheel will be pushed downward with further 6 tons and the two neigbouring wheels will unload three tons each when piston is midway.Going backward we are getting close to wheel lifting and that is a no-no.

The cure had been to drive onto third axle like everywhere else with 2-8-0s but this would have been very long connecting rods and considered unsafe at the time.

Deleted

If Holcroft and Jarvis had been in charge and started with the 9f it can maybe interes some hove ofsprings could have looked.

A three cylinder compound 4-8-0 can do anything a Pacific will do and burn less coal and for smaller jobs a 4-6-0 with either three or two compound cylinders

40 minutes ago, Corbs said:

 

Hi Niels, I have asked Huw for you, I’ve not see the report though.

Hello Corbs

Thank You for asking.

If it give some figures and analyses like the old BR steam test reports it will be very interesting for an old steam dreamer.

I hope it is not considered confidential but can easily understand and accept  if it is.

Thank You Corbs for saving my day.

In the interview it is mentioned that a test report was made for the 101,6mph test.

Can that be had by  the public?

A new numerical model run

Total train length 190meter making 1420 kW heating of air

Total train mass 485000kg making     347 kW  oil and rail heating

total demand on locomotive 2400 indicated horsepower.

We asume that an A1 can do 31410 lbs of steam per hour from 4260 lbs of coal showelled by two firemen.

This is the One hour figure from mr Cox/Britania.

A V2 used 13.2lbs  at best opperating condition and gives   2400 ihp on Tornado if it steams as well as a BR7.

The continious 3000lbs/h coal showelled by one unionized fireman makes 24000 lbs steam per hour or ca1800 indicated horsepower.

A drag plate area of 0.13squaremeter per meter train and a rolling resistance coefficient 0f 0,0015 gives reasonable estimates of steam train speed possible.

Thank You for reading

9 hours ago, DavidB-AU said:

It was being dragged for the test.

 

Cheers

David

 The simple numerical indicated horsepower for steam locomotives at steady speed calculator functions quite well

.

The Tornado train did 45,4meter per second.

Train was 210m long including Tornado and 67

Train mass was 573 tons all inclusive.

Rolling takes                385kW

Disturbing air takes 1570kW

or 2650 indicated horsepower.

Maximum steady ihp for a V2 on test plant was 1990 ihp

A Britania gave2200 ihp on rollers and a LMS pacific 2550.

One can use more steam than max steady evaporation rate but pressure goes down fast.

Tornado did not run 101,6 mph for many minutes  so it is not unrealistic that Tornado ca do 2650 ihp for a short while.

The LMS calculated over 3200 ihp when they measured 2511 drawbar horsepower in a short burst.

The difference between drawbar horsepower and indicated was asumed to be machine friction,locomotive rolling resistance and locomotive air resistance.

I find it more simple to se most of it as total train air resistance.

Indicated horsepower steam demand and boiler evaporation are simple to calculate.

This method can be used on electric or diesel trains  as well.

Total train length in m mutiplied by 0,13 (UK normal gauge)  0.15(Berne Gauge)  0.17(US) gives flat plate area in square meters

This shall be multipled by  0.5 *air density(1,23kg/m**3)*Velocity cubed and giv ve Watts for airwork.

Total train mass (kg)*gravity*0.0015*velocity gives rolling work in Watt

49 minutes ago, DavidB-AU said:

It was being dragged for the test.

 

Cheers

David

Damned.

My simple power model shot down in flames

But thank You for answering

1 hour ago, DavidB-AU said:

 

The diesel was there as backup and for ETS.

 

Cheers

David

Was it draging or pushing?

1 hour ago, DavidB-AU said:

 

It was 2 x Mk 1 (support coaches), 7 x Mk 2 and a 67. Slow to 0.25x speed at 0:44.

 

 

Cheers

David

Was it diesel supported?

13 hours ago, rodent279 said:

What are the figures for 10 or 8 coaches? Are they more believable?

Tornado doing 100mph with 8 coaches and the drag plate area 0.13 squaremeter per meter train calculates  to 1990 indicated horsepower or almost exactly what a V2 could give with more tube area but less firebox.

IWe are very close to a  simple formula for calculating needed horsepower knowing total length and mass of train, if Tornado took 8 at 100.

On 16/08/2019 at 12:01, Niels said:

Thank you

Drag plate area was then 154 * 0.215=33 square meter

Air power 0.5 *1.23*(56.5**3)*33=3660kW.

Rolling took 345 kW and thus total was 4015 kW and 1150 came from gravity.

Mallard must have given 2865kW or 3892 horsepower and that is impossible.

The drag plate per meter train was estimated from a known danish case and danish loading gauge and trains  are wider and higher than UK trains.

If we asume that a tape around a uk train is 15% shorte than a continental it calculates to 2300 kW locopower or 3133horsepower  or more or less what was the absolute max measured on a LMS Pacific.

If we asume UK trains have a drag plate area of ca 0.215*.85=0.18 square meter per meter train length we can use it to calculate power demand versus speed from locomotives be they ,steam,diesel or electric.

The danish IC3 train has been recalculated using better information for wheelpower and comes to 0.15 squaremeter per meter train length.

Mallards train had smaller crossection so let us say 0.13square meter per meter train.

Air resistance area for Mallard plus train can then be estimated to 154*0.13=20 squaremeter and airpower uses 2215 kW,rolling takes 345 and gravity gave 1150.

Mallards input can be calculated 2215+345-1150=1410kW/1915 horsepower and that is realistic according to Cox for a V2.

1 minute ago, rodent279 said:

Then I can only assume it was not level track, or there was a heck of a wind behind it! I would think a tour would be a minimum of 8, probably 10, to make it pay.

Or my 0.18squaremeter drag-flat-plate-area per trainmeter is to big.

The former Mallard calculation gave also very high  horsepower values.

48 minutes ago, rodent279 said:

What are the figures for 10 or 8 coaches? Are they more believable?

for 10coaches it will be2330kW/3165hp and for 8  1920 kW/2610 horsepower

2610 horsepower needs a lot of steam.

Will calculate

V2 had same boiler as A4 and same gas resistance as an A1 and gave 31000 lbs/hour steam and 1990 indicated horsepower as absolute maximum for more than a few minutes.

29 minutes ago, rodent279 said:

Not sure how many coaches that particular train was, but a typical Mk1 is around 35t, and just over 19m long. A typical railtour rake of 12 coaches would be 420t, and ~230m long.

 If 12coaches can be confirmed it means a 585 tons train ,250 m long doing 44m per scond on level rail and no wind.

Rolling resistance power 386 kW asuming  0.0015 as coefficient

Airwork comes as 2360 kW that is 2740kW/3727horsepower total.

That is way out of this world so either train was shorter,pushed by diesel or my numerical model is wrong.

On 16/08/2019 at 12:01, Niels said:

Thank you

Drag plate area was then 154 * 0.215=33 square meter

Air power 0.5 *1.23*(56.5**3)*33=3660kW.

Rolling took 345 kW and thus total was 4015 kW and 1150 came from gravity.

Mallard must have given 2865kW or 3892 horsepower and that is impossible.

The drag plate per meter train was estimated from a known danish case and danish loading gauge and trains  are wider and higher than UK trains.

If we asume that a tape around a uk train is 15% shorte than a continental it calculates to 2300 kW locopower or 3133horsepower  or more or less what was the absolute max measured on a LMS Pacific.

If we asume UK trains have a drag plate area of ca 0.215*.85=0.18 square meter per meter train length we can use it to calculate power demand versus speed from locomotives be they ,steam,diesel or electric.

It is maybe of interest to see if the power model is realistic.

Does someone know how long the train was that ran 100 mph pulled by Tornado and aproximate mass of wagons?

I have read that it was on level road and not assisted by diesel at the rear?