Just William (3.5 gauge 2-6-2)

[JonL]

One thing to note about my superheaters; they are non radiant and really fill the tubes they are in. They are not very well made and I think are possibly occluding firebox gas flow through the superheater tubes (the combustion gases, I think the steam is flowing ok).

I may just make a new set. It would be good practise for the Britannia. On the flip side, every time I do something on this locomotive the Britannia progress is held up even further! That being said, I'm still learning and enjoying myself.

[dhamblin]

Get some wagons - that'll give you a good load. Or take a leaf out of Alan's book and build a water wagon

Regards,

Dan

[JonL]

Stainless superheater darts ordered. Being stainless I think I'll project them into the firebox and make them radiant. The main advantage I think will be easier cleaning of these tubes as the old superheaters are not very straight and have an oversized bronze return bend which I think doesn't help flow. Practising on two medium sized superheaters will be a good trial run for the four darts used in my Brit.

[ejparrott]

Doesn't matter how big the coal is when you start, burning it reduces the size of it

[JonL]

It's hard to quantify an improvement but i was able to run with more cutoff with the radiant superheaters. Raking out the ashpan restored efficiency throughout the day whenever it dropped off, and on the whole it steamed very well for a 3.5" gauge Locomotive. I didn't have any issues with tube blockages this time (although i don't know why; the only thing i changed with regard to the tubes was improved gas flow around the superheaters by removing the restriction caused by the cast bronze return bend, and it wasn't really those that blocked).

An enjoyable day again. I've got a list of improvements I need to make, including an extension tool for my water pump bypass so I can improve my finesse with it. Too often I was dumping too much water in and killing off the pressure. It seems quite hard to find that perfect point that just replaces what I'm using.

[JonL]

youtu.be/ZCB8pjEZExE

Some footage of the running today

[mbrown]

I suspect a change of gas flow through the superheater tubes affects the gas flow in the small tubes. If it is flowing more freely through the flues, the draught through the small tubes will be gentler - therefore less chance of blockage.

That's my theory, anyway!

Malcolm

[stevep]

Jun 12, 2021 15:37:33 GMT JonL said:

youtu.be/ZCB8pjEZExE

Some footage of the running today

You must have been doing a scale 200 mph!

[JonL]

I don't think it's as fast as it looks; if you look at the gauge I'm quite low on steam. Limit is 5mph on our track, I reckon it was around that mark. Anything more is scary, I certainly wouldn't have been trying to film at the same time!

I think 3.5 looks faster than 5" as the wheels tend to be smaller!

[JonL]

Jun 12, 2021 17:33:42 GMT mbrown said:

I suspect a change of gas flow through the superheater tubes affects the gas flow in the small tubes. If it is flowing more freely through the flues, the draught through the small tubes will be gentler - therefore less chance of blockage.

That's my theory, anyway!

Malcolm

Sounds very reasonable. I certainly had a huge reduction in blockages.

[JonL]

It's funny, the smallest modification (or tool made) can make the biggest difference. I made a water pump bypass extension to allow me to tweak the bypass valve with more finesse, and I've found I can adjust the water filling far more effectively, in such a way that doesn't kill off the pressure accidentally. I raked out the bottom of the ashpan a couple of times today and good steaming was instantly resumed (it was almost full) and was able to do consistent laps stopping only for fuel and water.

I didn't realise it, but it's taken getting her to work properly before I could really learn how to drive her.

[JonL]

In the last couple of uses (I drive her at least a couple of times a month) I've had trouble raising and maintainingsteam. So I've done a little overhaul; improved the smokebox door sealing, resealed around the blast pipe and header with RTV, repacked all the glands (I didn't make these parts so they are still graphited string). Today I've had a run at the WWSME and found every working far more to my liking. I deliberately went with the aim of trying to improve my use of the bypass valve; improving my skills of keeping the water level up without killing the pressure stone dead. I think I'm improving. I hope I'm a half decent driver in time for the Britannia to hit the rails.

One interesting thing with the bypass; I was monitoring how much water was entering the boiler by the temperature of the backhead clack valve. Too hot to touch; no water going in. Cold, plenty going in. I was trying to hold it so that the amount going in was balancing what was coming out, and for the most part succeeding. What was interesting (and in retrospect bloody obvious) was that the amount going in wasn't just a function of the valve position but also of the boiler pressure.

Isn't it funny how some things are so obvious you don't notice them?

[kipford]

Jon
Like you I am learning to drive my Super Simplex. First time out with really only me on the driving trolley, no real problems managed to keep everything going. Took her out Thursday with Coniston and his B1 and another club member with his Terrier, much more difficult time. Had my first blow up and lost the fire twice! Big difference I was pulling a trolley with some friends on. We think I was over coaling and ended up with a full smoke box (that I forgot to clean out after losing the fire the first  time, I cleaned the grate though). Anyway thoroughly enjoying myself, there is a lot to learn!
Dave

[JonL]

I agree Dave, I think I was dismayed at realising it's not as simple as most people think...

One other thing I found is that things work much better if I keep pricking the fire through to make sure air is coming up through the grate. I wonder if the fire bars are too close together

[coniston]

Glad you're getting the hang of your loco Jon, 3 1/2" loco's are not as easy as bigger 5" ones so your progress is a real achievement. Ref. Kipford's grate, it may be a bit close on firebar gaps, it is in fact laser cut from stainless steel sheet, only about 4mm thick IIRC but it has run with that one for many trouble free years. Like you Dave just needs more practice.

Chris

[JonL]

After a long layup, stripping down and improving where I could, I got Jamie steamed on the rollers today. Fire came up lovely and stayed good all day, lubrication worked etc etc. A quick glance at the eccentric for the water pump suggested why I wasn't get water into the boiler, it was slipping on the axle! That and a few other things (it sounded a bit off beat so I'll redo the timing and geometry) has given me some things to look at, as well as some I didn't expect (the blower fan was dry on its bearings, wouldn't have had that with Roger's bypass design). Otherwise though I'm delighted to say it looks like I might be terrifying my MES again early next year.

[JonL]

I've checked the timing and can't see anything amiss (I even marked the positions of everything last time when I got it as close as i could within the limitations of the tolerances of the valvegear, in some places its not very tight). Further investigation required.

[JonL]

I've looked more closely at the timing and although it appears to be correct there is a bit of lost motion here and there. In particular the eccentric crank bush had a lot of slack both sides, and on inspection were oval. Maybe I'm not lubricating often enough as this isn't the first time I've found wear in what is a relatively young engine. Anyway, rebushed now, lets see how she goes.

[JonL]

Removing the lost motion (including a lot in the reversing stand I hadn't noticed), improving the seal of the firebox door, better coal, blastpipe alignment. It all made for a fantastic day of steaming. By the end I was grinning like mad.

[JonL]

Further sealing of the smokebox split seal has resulted in a much easier to drive locomotive. Next job was sorting the lubricator.

She was routinely clicking over two teeth of the ratchet, so I made a bellcrank linkage to go between the expansion link and the lubricator arm. Now she seems to only want to give it one click at a time. Hopefully I can reduce my oil consumption and my looking like a bald spiv after every run!