Garden Railway Forum

Hi Rik,
It appears that the cylinders are not geared to the driving axle but drive direct (ie crankshaft on the driving axle) so except that the cylinders are vertical it would sound the same as any two cylinder loco, that is four beats per revolution.
Grant.

ge_rik wrote: Wed Jul 31, 2024 4:35 pm looking at this video of Chaloner on the Leighton Buzzard Railway - it looks like it's actually four chuffs per rev. Have I got that right? Can one of you steam buffs explain how that works?

To expand on what Grant said -

The vast majority of steam engines have double acting cylinders. Each cylinder stroke is a power stroke, so a single cylinder steam engine has two exhaust beats per rev of the crankshaft.

Chaloner has two cylinders, but isn't geared, so you will hear four beats per rev at slow speeds. The prototype of my Thos. Green built VB tram engine is geared 2:1, so it would have had eight beats per rev. At any speed the exhaust on the model is just a continuous roar, as the beats merge together.

It gets weirder when a steam engine has more than two cylinders. Three cylinder Gresley locos have six beats per rev, but they aren't evenly spaced. Some four cylinder engines have four beats per rev, others have eight, depending on how the cranks are set.

A three cylinder Shay, with 3:1 gearing will have eighteen beats per rev of the wheels. Shays don't chuff, they roar....

To complicate it further, steam engines work expansively and as the speed increases, the driver changes the cut-off, so the exhaust beats get softer. At mainline speeds the exhaust sounded more like the roar of the blower than a series of discrete chuffs.

Hope that makes sense, it's morning here and I'm still on my first cup of tea.......

Graeme

Thanks chaps. That makes perfect sense.
I should have worked out for myself that they are double acting cylinders

Rik

ge_rik wrote: Wed Jul 31, 2024 4:14 pm The alternative is to file a flat which I've done for the grub screws on the bevel gears. I might then be able to slip a wedge into the gap. The eccentrics are resin printed so I can't really rely on grub screws. Not sure I have sufficiently reliable kit to drill neatly through a 3mm axle to pin them.

Rik,
Quite by chance, I've just come across this on fleabay.
It sounds as though they might grind a flat wherever you want it, or of course you could just use the D-axle all the way through.
https://www.ebay.co.uk/itm/387095733771 ... d_source=1

philipy wrote: Sun Aug 04, 2024 12:44 pm

ge_rik wrote: Wed Jul 31, 2024 4:14 pm The alternative is to file a flat which I've done for the grub screws on the bevel gears. I might then be able to slip a wedge into the gap. The eccentrics are resin printed so I can't really rely on grub screws. Not sure I have sufficiently reliable kit to drill neatly through a 3mm axle to pin them.

Rik,
Quite by chance, I've just come across this on fleabay.
It sounds as though they might grind a flat wherever you want it, or of course you could just use the D-axle all the way through.
https://www.ebay.co.uk/itm/387095733771 ... d_source=1

Great idea. A pity they don't do them in 3mm dia, though.

Rik

ge_rik wrote: Sun Aug 04, 2024 6:05 pm
Great idea. A pity they don't do them in 3mm dia, though.

Rik

Oops, sorry. I was looking for 3mm axles and this popped up. I just assumed it was 3mm without digging down further.

I've just done a further search and come up with this:
https://www.ebay.co.uk/itm/155702206912

philipy wrote: Sun Aug 04, 2024 8:23 pm I've just done a further search and come up with this:
https://www.ebay.co.uk/itm/155702206912

Thanks for the extra digging.
I've placed an order. Only 55mm lengths left and it looks like I bought the last pack of ten. I think it's coming from China - I had to pay in USD.
I'll let you know how they turn out.

Rik

This is v3. As a result of this build, v4 should be slightly improved.

I think this must be my most fiddly scratchbuild so far. Because much of the gubbins is on-show, there's not much room for the behind-the-scenes electrics, and so a fair amount of tweaking and adaptation was required. Also, unlike most of my builds so far, I had to do a lot of the painting before assembly.

There's still a fair bit more to do - mostly pipework, nameplates, number plates, buffers, couplings and a few minor details. Nearly there!

I wonder is Mk 5 will include an operating reversing lever with animated driver? Might be a step too far......



Rik

Lovely job Rik. Just watched on youtube before finding your post here. Everything seems to be working as it should and looking fine.

Looking good!

ge_rik wrote: Wed Aug 21, 2024 8:02 pm Because much of the gubbins is on-show,....

Hi Rik,

the loco looks great.
I also would add a small solenoid or friction mechanism (brass strip behind the wheel) in order to move the reversing lever correctly.
With all these things exposed, they need to be correct.
This is what makes these locos interesting. You can see the whole mechanism working.

Now added pipework, buffers and couplings - plus as much lead flashing as I could squeeze in. Seems to be able to haul a decent load, but I'd like to add more lead if I can. Better to be too much than too little is my motto.







Rik

Very nice end result, Rik.

P'raps I won't bother finishing mine after all!

Looks the part and performs very well with that load on.

Very nice.

philipy wrote: Fri Aug 23, 2024 4:40 pm Very nice end result, Rik.

P'raps I won't bother finishing mine after all!

There can never be too many de Wintons in the world to my mind

Rik

Sorry Rik, just catching up, but didn't want to miss the opportunity to add my admiration too - that's very impressive. Good haulage capability, looks like it'll be a useful loco - and something a little different too...

Cheers,

Andrew.