Topic: Cheddar Models - Pelican (Read 38511 times)

gondolier88 · « **Reply #50 on:** July 27, 2009, 03:13:01 pm »

Hi Solitary Sailor,

Only ever do what your confident in doing, thats fine.

A simpling valve equalises the pressure on the IP cylinder to being the same as the HP cylinder- this is done by running a pipe from the HP valvechest- or the steam supply pipe- and the IP valvechest on starting.

This means that if the HP cylinder is at TDC or BDC the IP cylinder of course won't be and will start the engine instead of the HP cylinder.

Simple really, or should that be simpling?

Greg

Solitary Sailor · « **Reply #51 on:** July 27, 2009, 03:58:20 pm »

Well, One thing is for sure, I'm getting a great refresher course (much needed too I might add). Alex and Greg, thank you both for your considered arguments ... for while confusion may reign today, I am sure as revisit this thread in later days, a lot more of what you are imparting will make more sense to me. So again, from the bottom of my heart, thanks for the time, patience and experience.

Alex, Mike's point about the 5" over the 4", was not about its ability to provide enough steam, but about its capacity to boil water sufficient to maintain a reasonable head of steam for more than a short run time for a model out on a lake. The 4" with a capacity of 900 ml, vs the 5" with a capacity of 1.7 L, and of course the dual burner of the 5" to keep up with a thirsty engine.

I do seem to recall that the Stuart Triple was recommended to be driven with a higher steam pressure, Greg's figure of 120 psi rings a bell.

As I will probably purchase one of Mike's 3 1/2" boilers first (for the Puffin), I can use this to do some experiments on the triple to see how well she works at 50 - 60 psi, (long run times not needed for this), more to test out how prone the engine may be to stalling , how smoothly she turns over, possible modifications, ie injectors, etc. Lots to do, and I haven't even bought the boat yet

Solitary Sailor · « **Reply #52 on:** July 27, 2009, 04:13:06 pm »

Yes, the SIMPLING valve does sound simple. I think all I would need to do is tap another steam line into the I.P. valve chest, with a pipe tee'd off of the main supply, with a cut-off valve operated by a servo operating on a self neutral return / momentary contact signal from the Tx put simply, let the spring loaded control stick on the Tx go as soon as the engine starts, or maybe count to 3,

... see ... even I can get that.

Anyhow, just got a call from a customer, he didn't get much sleep last night, his Air Conditioning broke down ... so it's off to work for me .. got to earn more pennies, those boilers are costly things

. May catch you again, probably just before your bedtime

gondolier88 · « **Reply #53 on:** July 27, 2009, 05:06:42 pm »

Sounds like a plan with the simpling valve- would be really good to see it working too.

Greg

Solitary Sailor · « **Reply #54 on:** July 28, 2009, 03:00:56 am »

Actually guys, I think this may be even easier than it at first appears ... I already have the extra tap into the I.P steam chest - the little tap and steam pipe for the I.P. pressure gauge. Cut that pipe and insert a 'Tee' and run a pipe to a shut off valve, and then to the main steam supply line. Though the pipe in question is of a very small bore, I doubt any great volume of steam would be required to 'bump' the piston enough to turn the crankshaft enough to open one of the ports on the H.P. steam chest.( Remember, when stalled, there will be NO pressure in any of the cylinders). Then as soon as steam acts upon the H.P. piston, the greater flow of steam through the normal steam pathways would probably overcome the small amount injected through this 'backdoor', even if it does momentarily hang 'open' Should be an interesting little experiment.

Solitary Sailor · « **Reply #55 on:** July 28, 2009, 03:17:16 am »

The more I think about it, it doesn't really matter if the injector stays open a little too long, as it will just mean that the I. P. cylinder is acting like a twin (with the H.P.), or almost, depending on just how much steam the injector allows into the steam chest, as opposed to the natural flow of reduced pressure, supplied from the H.P. discharge port.

See Greg, Alex, I told you my brain works slowly sometimes. What you have told me over the past 24 hours would appear to have sunk in.

gondolier88 · « **Reply #56 on:** July 28, 2009, 10:03:13 am »

Hi,

Your absolutely correct- once the crank has turned 1/3 turn then the HP cylinder will act as normal so it wouldn't require much steam in the IP at all.

In really large triples they use something called a barring engine, have you heard of those?

A large fine toothed gear was put on the crankshaft or milled intro the flywheel- then a small donkey engine with a small toothed sprocket would engage with the large crankshaft one and 'bar' the crankshaft round- this was used if the HP was at BDC or TDC and also to warm through the engine- a tiny bit of syeam would be admitted- not enough to turn the engine, just enough to warm the cylinders through so with the barring engine running the steam would be admitted to all the cylinders until they were warm enough to be run at full pressure.

See pic of the Corliss type barring engine.

Greg

Solitary Sailor · « **Reply #57 on:** July 28, 2009, 12:18:59 pm »

Hi Greg

That Corliss barring engine is an interesting little piece of engineering.

Do you, or does anyone for that matter, know of any full size Triple Expansion Marine steam engines still in existence anywhere, in some museum or on an old restored ship - Hah, fat chance of that I suspect, businessmen and politicians/bureaucrats don't do culture/history all that well

must be something to do with the fact they're all too busy stuffing their pockets all the time

. Anyway, I don't recall seeing any when I used to go to the science museum in South Kensington years ago, but then again, that was - years ago.

Any chance of some piccies of that slip eccentric you mentioned earlier Greg?

RickF · « **Reply #58 on:** July 28, 2009, 01:01:40 pm »

There must be quite a few triple expansion engines lurking in museums and preserved ships. USS Olympia (Independence Seaport Museum, Philadelphia) has two, for example, as does the Mikasa (Yokosuka, Japan). The Aurora (St Petersburg) has three.

Rick

knoby · « **Reply #59 on:** July 28, 2009, 01:17:35 pm »

Hi Solitary Sailor,
You made a lovely job of the triple, I'd love to own it myself. It would look great in a model, although there are issues with the practicality of control. I remember see one in a huge model of a sun tug years ago ( mid 70's i think) it used an electric motor for starting & a complicated system to change fwd rev gear.

The first example of a full size triple that sprang to mind was in the Challenge tug. I visited the tug many times when she was moored at St Catherine's dock in London. Have a look here
http://www.stchallenge.org/Home%20page.htm

Cheers Glenn

Solitary Sailor · « **Reply #60 on:** July 28, 2009, 01:52:08 pm »

Thanks Rick

The Americans always were more careful of their own heratige, and I had forgotten about Mikasa. Maybe one day I shall stir myself out of my dislike of travel, and go visit St Petersburg. I come by that aversion naturally, for as a service tech/contractor, my work takes me to customers' houses and businesses, and over the years I've racked up some mileage I can tell you, last guesstimate, based on an average annual mileage of 21,000/year, that's about the equivalent of 28 times around the world at the equator, all behind the wheel of a truck/car ... I'm sick of the sight of the road

Hell, my current truck has 304,000 miles on it and still going strong ... bless 'er.

The British, as a nation, aren't so keen on preserving their heritage, as it would appear to be somewhat embarrassing for the PC multicultural revisionists now in charge. I remember years ago, going to the science museum in South Kensington, for the last time, and being very disappointed as they had removed almost all of those wonderful old shipyard builders models which used to be on display, and being told by my university educated friend that these were signs of a decadent Imperialist past, and as being none inclusive must be discarded to make way for exhibits more conducive to social cohesion .. this was 30 odd years ago I know that many museums are now commissioning models from people like John Haynes, but what happened to those old models? More power to people like you Greg, for going that extra yard and being part of preservation societies.

As if to prove my point ...from the link posted by knoby "Did you know that vessels that move are not to be protected under the new heritage protection legislation". Right there on the bottom of the opening page ... grrrrr By the way knoby thanks for the compliment, and the link. There may be more than I suspected, but in Britain, there is always a struggle to sustain the preservation of many aspects of our heritage. Our elites are embarrassed by it all ... either that, or too busy with their snouts in the trough!

Sorry about the rant, but it is a subject which really gets my goat

Circlip · « **Reply #61 on:** July 28, 2009, 01:56:27 pm »

We don't preserve cos we're SKINT.

Regards Ian.

Solitary Sailor · « **Reply #62 on:** July 28, 2009, 02:06:26 pm »

Hi Ian

You got that right, but it doesn't explain whats been going on these past 50 odd years. Skint or not doesn't seem to stop the spending spree on their pet projects either.

Circlip · « **Reply #63 on:** July 28, 2009, 02:25:50 pm »

The Aircraft preservations are MAINLY done by enthusiasts and by begging, but the difference is that if every boat was preserved that everyone liked, the cost, not only to preserve the vessel but also a suitable site?? Obviously not all in one place.

Regards Ian.

Solitary Sailor · « **Reply #64 on:** July 28, 2009, 02:39:40 pm »

Hi Glenn

Your comments about the difficulties of controlling the start-up and forward/reverse mechanisms,may not be all that complex. For the start-up, see above commments ... I think we may have that one licked

, the forward/reverse, again not too difficult ... either remove the reversing hand wheel and threaded drive shaft which throws the Stephenson valve links over, and attach the servo directly to the arm which moves the whole assembly, or attach a drive motor with a slipping clutch, maybe something like a sail winch servo, to operate it just as a real human mechanic in the engine room would have

gondolier88 · « **Reply #65 on:** July 28, 2009, 02:53:42 pm »

Hi solitary sailor,

Rant accepted!!!! However, perhaps wrong choice of words, as a NATION britain is very keen on preservation, in fact it's big business for tourists, SY Gondola being a case in point. However the people 'up there' don't want to spend their precious economy saving billions on such things as unique peices of engineering that tipify the pinnacles of manufacturing that were reached by britain- the national lottery fund was a fntastic way of independant groups being able to finance otherwise impossible projects- but nowit's rumoured that more than 50% of money that was ALREADY allocated has been shifted to the 2012 olympics!!!! I love sport, but once it's over we are left with huge faciliteis that need £100,000's a year just to run- we might get the money back into the ECONOMY, great, but we won't see it back in the lottery fund for a long time- a crime in my eyes!

You've got me started now too!!!

I'll be on Gondola on friday so i'll get some good pics for you mate.

There are some fantastic triples still in preservation. Check out-

http://www.ss-shieldhall.co.uk/- twin triple powered sludge boat
http://www.thebratch.org/- bratch pumping station- two triple pumping engines- one working
http://www.kbsm.org/exhibits/triple - really lovely preserved triple at Kew Bridge Museum
[url]http://www.waverleyexcursions.co.uk/steamengine.htm [url]- really impressive triple horizontal paddle engine on PS Waverly

There are more, I’ll leave it upto you to find them…

Greg

Solitary Sailor · « **Reply #66 on:** July 28, 2009, 03:11:40 pm »

Ian

Not everything can be saved ... but there's not an awful lot left from the beginning of the last century and before. But when a project gets a high enough profile, look what can be done ... just look at the SS Great Britain. I remember when she was brought back home from the Falklands, what a sorry sight she was, and look at her now. Admittedly that had Jack Hayward as its main motivating force, see what can happen when a rich man puts his efforts into something good. Unfortunately, most of us ain't that rich

As regards docking fees ... well, the government isn't exactly short of marine properties, well, they didn't used to be... who knows what they have now after all the yard sales they've had recently to sell off everything to pay for all their preferred projects...like the fiasco of the Olympics springs to mind. Anyway, many of the older examples would probably fare better, out of the water. Not strictly kosher, but for many, maybe the only way forward for long term maintenance.

And yeah Greg, my condemnation is reserved for the elites who rule, and not the people, as I acknowledge, people in preservation societies do Herculean tasks to maintain and restore their local projects, more often than not on a shoestring, while there are millions to waste on absurd schemes, mostly to do with grandiose social engineering experiments ... human beings should not be in the business of manipulating others. what was it Rousseau said ... "Man is born free, and everywhere he is in chains" (and no, he's not my favourite philosopher, but he got that point right)

Solitary Sailor · « **Reply #67 on:** July 28, 2009, 03:26:46 pm »

Well, that's my original contention shot down in flames

There are indeed some wonderful examples still extant. I still reserve the right to whole heartedly condemn the elites for the useless parasites that they are.

Solitary Sailor · « **Reply #68 on:** July 28, 2009, 05:37:25 pm »

"I'll be on Gondola on friday so i'll get some good pics for you mate."

Thanks Greg, I look forward to seeing it ... together with a nice fulsome descriptive narrative upon all the strange bits and bobs

Well, this thread has wandered around a bit, but it has produced some interesting links, and even one or two ideas.

Back to the original point ... the little 'Puffin', given that the model boat it will most probably go in, is likely to be second fiddle on the production schedule, as I do intend to start with the St Nectan next, (already half way there with the penny jar for the purchase + shipping price); it will be awhile before anything concrete gets underway, although I will probably dabble in prep work, as I do already have both steam engines. And sorry Greg, while some of the steam launches shown here are extremely beautiful models, and maybe one day I will do one, but when a model is out on the lake, unless it's right under your nose at all times, you wont see much of that little 'Puffin' in action. In fact, probably not a lot more than a steam plant in a tug or steam fishing trawler, as all the prep work is done shore side, as you really get to see it up close. See, I like working boats, not idle mens toys

gondolier88 · « **Reply #69 on:** July 28, 2009, 06:52:17 pm »

You stick to your guns mate!! A great steamship is better than a good steam launch after all.

You could start fiddling with setups for the simpling valve- looking forward to seeing that.

Plenty of pics and 'descriptive narrative' on it's way...

Greg

Solitary Sailor · « **Reply #70 on:** July 28, 2009, 09:16:54 pm »

Hi Greg

A quick question ... do you think this little 'Puffin' is up to the job of powering a tug with dimensions of 45.5" long, by 12" beam. Given that the 'Victoria' is almost the same length (a little shorter), but with a narrower beam, I wonder if I might be expecting too much out of it. I would like a model which would have a reasonable turn of speed ... not a speed boat type, but one which could generate a reasonable bow wave, with a nice impressive wake, and not one which appears to be gliding through the water with effortless ease and little disturbance of the waters around it.

gondolier88 · « **Reply #71 on:** July 28, 2009, 09:29:07 pm »

Good question- i've only seen a twin Puffin arrangement in a tug of that size so I couldn't say for definite, but I think it would struggle to be impressive put it that way- however as you have got the plant already and not weighing up pros and cons prior to purchase I would put it in the hull with some ballast to represent full boat weight and stick it in the local pond with a rope tied on- purely to test the 'driveability' of the boat.

What size/pitch/no.bladed prop will you be using?

It is a big displacement at 12" beam to be honest so optimistically I would say it will move under full power with a fair wake, but anything less than full power would be a little 'graceful' for your tastes- certainly wouldn't bet on loads being pulled by it- sorry to sound so 'bringer of doom'.

Will just have to suck it and see- nothing to lose after all- as I say you own all the bits you need to test it.

Greg

Solitary Sailor · « **Reply #72 on:** July 28, 2009, 10:42:13 pm »

With the above advice in mind, I may lower my sights a little to an 'Envoy' tug from Model Slipways at 43" long, by 9.5" beam. On the bright side, the model is cheaper ... by over a hundred quid, so not so much to lose. Then again, if worst came to worst with the original "Cruiser", I could always rip out the steam plant, and stick an electric in its stead ... blasphemy I know, but a tug better have the ability to tug something, or its about as much use as t*ts on a bull

or continue to pursue my insanity and go looking for a bigger steam engine to mate up with boiler and boat

gondolier88 · « **Reply #73 on:** July 28, 2009, 11:00:07 pm »

Envoy might be a good idea- or theres a triple I know of somewhere...

Greg

Solitary Sailor · « **Reply #74 on:** July 28, 2009, 11:11:09 pm »

Errr... the triple might be akin to trying to stuff a fat lady into a pint pot

Yes, Yes, a sight to behold ... but still.

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Author Topic: Cheddar Models - Pelican (Read 38511 times)

Solitary Sailor

Solitary Sailor

Solitary Sailor

Solitary Sailor

Solitary Sailor

knoby

Solitary Sailor

Solitary Sailor

Solitary Sailor

Solitary Sailor

Solitary Sailor

Solitary Sailor

Solitary Sailor

Solitary Sailor

Solitary Sailor