Drain cock valve asthetics....honest answers wanted

[Mcgyver]

Trying to put the push on to finish a Stuart Triple and need drain cocks.

I dislike the typical style, you know the bent over hand that acts as a taper plug.  I find them finicky,  either they leak, or have to pressed in so hard they don't operate smoothly.

.....and.....

Not really a rivet counter, but I do like an engine to have a prototypical appearance.   Not even sure if there is a prototype for the ST triple (if no prototype, isn't it just a small engine vs being a model?) however I would like it to look right for the era and type of engine it represents.   


...... so......

If made to size, would a valve of the type shown below be appropriate for a cylinder drain cock?   I don't have enough exposure to full size engines to have a sense of it.....just fine or an abomination?  Would the model engineering greats of the past be rolling over in their graves (and you a guys and gals think "uncouth colonial" lol)

It know its my engine, but I want to look correct..... how much latitude do I have?

Thanks!

[simplyloco]

I take your point, and you might find the drain cocks fitted to our ME locos would be suitable. These ones can all be operated with one lever arrangement.
https://www.maidstone-engineering.com/collections/cylinder-drain-cocks-oil-cups

If you want to make your own here is a miniature valve from Roy Amsbury. My 3.5" Britannia is festooned with his designs!

[Michael S.]

Here are two pictures from the valve catalogs from around 1910.
The second picture shows drainage valves. All made of bronze.

Michael

[Charles Lamont]

In so far as the The Stuart triple represents any prototype, it would not be a large engine, say Elliott Bay size up to maybe about 8" stroke. Typically the drains on an engine of this sort of size would be taper plug cocks. That is also what was invariably used on UK traction engines/rollers etc.

The Roy Amsbury design in Simplyloco's post looks like a Great Western injector steam valve, not really comparable with a cylinder drain cock.

(Incidentally, full size British locomotives had 1/4 turn cocks on the water gauge, three of them: top fitting, bottom fitting, and drain. You need to be able to snap the drain open and shut quickly to check the gauge is reading properly. The top and bottom cocks were frequently linked by a lever. When a glass breaks you throw your overall jacket over the gauge frame and slam the cock lever closed in one movement, and that is even though the glass tube has a thick plate glass gauge protector round it.)   

[internal_fire]

It know its my engine, but I want to look correct..... how much latitude do I have?

The body seems fine unless it is too big.

The handle looks a bit like it comes from a garden hose spigot. Even so, there were American locomotives that used handles just like that on some backhead valves.

It is pretty easy to make a new handle.

Gene

[simplyloco]

SNIP

The Roy Amsbury design in Simplyloco's post looks like a Great Western injector steam valve, not really comparable with a cylinder drain cock.

SNIP

Agreed. I offered this miniature design as the OP declared a dislike of taper plug valves.
John

[Dave Otto]

Here is one of the nicer triples that I have seen, it won best of show (people's vote) about 2010 at the GEARS show.
This engine was built by Ken Beslin from Washington state. It has lots of nice detail including the drain cocks that may be more fitting on an engine of this size and style.
Here is a link of a different view. https://pbase.com/captain_carl/image/129242879



Don't you just love that wood base?
Dave

[cnr6400]

I noticed at the end of the text in the second ad the housings were noted as cast iron or cast steel, rather than bronze. Great to see the old ads!   

[derekwarner]

Whilst we understand the limited space available for such condensate blow down valving, the example work on this model certainly looses the symmetry of vertical and horizontal tube/ pipework of the design period

Even the header tube run from the actual cylinder ports are inclined at a slight [8 degrees?] angle off the horizontal!?, and the valve actuation spindles are at odds with each other

Derek 

[Jasonb]

If you are going to plumb the valves to waste then there is no reason not to have small dummy valves on the cylinders and something more practical out of sight under the base.

looking at the various marine engines on a site like Preston Services will show that they all seem to be lever operated and likely 1/4 turn tapered style. You could go for parallel spindle in PTFE sleeve but at the size of the Stuart it starts to get a bit small.

[Michael S.]

I built these four corner valves on my Stuart compound and a central valve on a replica D10.
I could already see both variants on the large original machines.

Michael

[Mcgyver]

great comments, thank you, learning a lot.  Michael and simplyloco, very nice work!

I've been playing around with this, but didn't want to prejudice your views on what should be done with photos of what I've made so far.  I'm not at all decided, hence the thread, but my first thought was a sort 90 degree needle valve.  The 90 degree part hasn't been machined/soldered yet, but it gives a sense of what it looks like.  The 90 degree part will allow a drain pipe so as to route the condensate down and under the engine instead of spraying all over.  For the valve bodies I set up a turret lathe and cranked them out.

A had a simple bar as a lever which looks ok.  I like idea of redoing those with a more "ergonomic" tapered handle.  Then I trying casting I made some miniature valve handwheels.  Still having problems getting a good casting, lots of surface flaws, but they are getting there.  I like the look of them, but wondered if they'd look out of place on the side of the engine.  I think this thread is steering me toward yes, they would look wrong.  I'll maybe use them for pipework in general, but I don't they belong on the side of the engine. 

Routing everything down and then having a valve is interesting, hmmmm

I like the reversing handwheel on the triple pictured above.  I've included a photo of one I did that is similar, I cast it in bronze.  Still getting some casting flaws, so may try again.  I probably tried that part 10 times and each takes a lot of time.  After hundreds of dollars in expensive resin and six months of fails, I'm blaming the resin.  Very frustrating.  oh well, I shall preserve!

I welcome any comments, and no feelings will be hurt at this end

[Mike R]

I have a question that is related to this thread, what is the effect, if any, on the engines performance - theoretical or real - from having the extra dead space in the drain tubes for remotely located drain cocks?

[steamer]

Sabino's    from some years ago

notice the crossed lower drain valve.

Their actually pretty easy to make....

[Jasonb]

In model terms I don't think the added volume of a pipe (unless excessively large) with the valve at the far end will make much difference, things like drilled rather than cored passages and not shaping the cylinder covers to closely follow the piston shape will have more effect.

Then there is the question of how the engine will be used. Run on air with the cocks just a eye candy as many are then not worth worrying about. Run on steam but just for display again a reasonable number run that way where so long as it runs which it will then not a problem with the extra little volume. Being put in a hull of a good size model and expected to do work, I doubt many will be run that way where performance and economy of steam come into play. In fact the valve set away from the engine can be something that is easier to operate by remote control and 1/4 turn would really be wanted

[uuu]

I have a question that is related to this thread, what is the effect, if any, on the engines performance - theoretical or real - from having the extra dead space in the drain tubes for remotely located drain cocks?

Once you've exhausted the water through the pipes and closed the valves, the residual steam will likely condense, so the pipes will end up full of incompressible water - so no lost volume.

Wilf

[simplyloco]

I have a question that is related to this thread, what is the effect, if any, on the engines performance - theoretical or real - from having the extra dead space in the drain tubes for remotely located drain cocks?

Once you've exhausted the water through the pipes and closed the valves, the residual steam will likely condense, so the pipes will end up full of incompressible water - so no lost volume.

Wilf

Spot on Wilf!
John

[Mcgyver]

Steamer, thanks for those photos.   That somewhat validates using the crown hand wheel type valve.  I like the look of those handles, looks antique as they should.  I might try casting some like that.

[steamer]

Steamer, thanks for those photos.   That somewhat validates using the crown hand wheel type valve.  I like the look of those handles, looks antique as they should.  I might try casting some like that.

For my boat  I modified a standard 90 degree valve by adding a coupling in line.