Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length.

[Underpressure]

I'm just getting back into model steam boats, after a long lay off and dusting off models and projects.

One project I want to complete this winter is the conversion of what was an electric powered large twin screw tug to steam. I have no idea what the tug is (pictures in due course), but it is POF and was clearly built to take steam originally (lots of insulation already installed).

The intended plant for the tug is a Cheddar Pegasus  V4 oscillator with a Proteus boiler. The Pegasus has a water pump built in and there is plenty of room in the bow of the tug to accommodate a water tank, but given the restrictions of the displacement lubricator, is there really any point of arranging a tank and the associated plumbing, when in reality I will be pulling the model in every 30 to 40 minutes.

I have my own thoughts on the matter, but thought I would offer the subject for discussion.

Neil

[kno3]

Hello, do you mean that the lubricator's capacity is too small? If yes, you could consider changing it with a larger one with an adjustment valve. That's quite useful because the non-adjustable ones like Cheddar uses seems (in my experience at least) to dump the too fast in the steam line.

[Underpressure]

Increasing the size of the lubricator was not something I'd thought about, it would be pretty easy to do and would extend run times for sure.

Thanks for that.

Neil

[HS93 (RIP)]

the problem with a water tank in the bow is that when the water is used the bow rises and depending on the amount of water you are going to use it can be a lot, I have used twin side tanks with a simple cross tube to keep them balanced they are hull shaped on the back but only about 25mm x70mm but are quite long so don't take a lot of space, have you thought of fitting a mechanical lub system a twin pump so you can use one side to spray the big ends.

http://www.steamfittings.co.uk/asp/components_subcats.asp?CatID=18


 the Pegasus  V4 oscillator is an engine I have always wanted

Peter

[gondolier88]

I thought exactly the same as you regarding water tanks on the Krick Victoria I built, thinking that you woudn't need them, I fitted them just so I didn't have to take the safety valve out every time we needed to fill up. However subsequent tests have shown that we needed an engine driven feed pump constantly feeding because the boiler used that much water- 30 mins on the water is 15 mins to get where you want and 15mins back again- but factor in high speed running, safety valve leakage etc and it ends up being about 20mins useable time- and if you were constantly manouvering a tug you'd get even less.

Fit water tanks with engine feed pump!!!!

Greg

[derekwarner]

Neil....if we spend say 1000 EURO on an engine & boiler...one of the cheapest insurances is a visual on the remaining steam oil in the lubricator......visit the WEB site of  http://www.modellbau-niggel ....brillant quartz glass tubed lubricators......Derek

[kno3]

I can second Derek's recommendation, I'm using those lubricators too and they are really good and easily adjustable.

[Underpressure]

Peter,
       I'm not really too worried about the lubrication of the engine, I recall John running a Marie Felling equipped with the Pegasus for extended periods without the need for anything more than dashpots. The beam of the tug is also wide enough to accommodate 'saddle' tanks, I am just wondering if there is a need for additional water at all IF I keep my runs to round 30 to 40 minutes, which is a pretty usual slot at most clubs and events (or at least it was, the last time I was active).

I think the Pegasus was a highly underrated engine, I sailed the Marie Felling on several occasions and it was a smooth and powerful plant. Just before his illness, John was selling the last batch to 'selected' customers at around cost. I think John said at the time that they only ever produced one batch of machinings. The trouble was visual, you can put a Proteus on show in a nice open launch, the V4 does not have the same impact. Not a problem for me, I prefer working boats, but lots of people like their plant to be seen, hence the Proteus and Gemini.  

Greg,
        I must sail like an old duffer by comparison to you! I have a Saint Class tug about 40" long, equipped with a Puffin (originally bought as machined kit in 1993), I also have an Antheo with a Puffin plant, I can easily get 30 to 40 minutes from either, without the need for water tanks, but I AM open to persuasion.

EDIT: Those lubricators look VERY nice, I might have to treat myself to a couple of early Christmas pressies.

Neil

[BarryM]

Neil....if we spend say 1000 EURO on an engine & boiler...one of the cheapest insurances is a visual on the remaining steam oil in the lubricator......visit the WEB site of  http://www.modellbau-niggel ....brillant quartz glass tubed lubricators......Derek

Website address appears incomplete. Will you please advise - I fancy the sound of the lubricators.

Thanks,

Barry M

[gondolier88]

Greg,
        I must sail like an old duffer by comparison to you! I have a Saint Class tug about 40" long, equipped with a Puffin (originally bought as machined kit in 1993), I also have an Antheo with a Puffin plant, I can easily get 30 to 40 minutes from either, without the need for water tanks, but I AM open to persuasion.

Neil

 

[Underpressure]

Website address appears incomplete. Will you please advise - I fancy the sound of the lubricators.

Thanks,

Barry M

Barry,
       just add .de to the address, that should get you there.

Neil

[BarryM]

Neil,

Ta,

Barry M

[Bernhard]

http://www.modellbau-niggel.de/

[BarryM]

Try browsing through the 'links' listed on that website - you don't have to know German to appreciate some beautiful examples of engineering.

Barry M

[Bunkerbarge]

Back to the original point of the thread though, is the water tank worth it, to me very much a yes.

The main point is that to fill the boiler up without a pump you have to vent off the boiler, which is a huge waste of heat energy and then, when you've filled it, you have to waste a load more gas getting it up to temperature and then pressure.  The problem here is not just wasting gas but greatly increasing the effects of cooling the gas tank.  Options are to use an engine mounted pump and either a manual three way valve or a level control system or a manual pump.  Either way you maintain the pressure and don't loose quite as much energy.  You can also think of filling from an external tank with a manual pump.

As regards weight, when you consider a lot of scale steamers and tugs are into the 30-40lb displacement range the amount of water needed to fill the boiler is negligible and will make very little difference to the draught.  If you are still bothered though you can use an on board tank but run around with it empty and then only fill it when you want to pump up the boiler with a manual pump.

Another consideration is the fact that you have a seperator to empty as well as the lubricator to fill, the gas tank to fill and the boielr to fill.  It's no good if the oiler hold enough oil for an hour then the seperator needs emptying every fifteen minutes.  I would try to aim to get everything to need attention at round about the same time and I think 30-40 minutes on the water is a good time to bring it in for a check over anyway.  At that point empty the seperator, fill the gas tank, fill the boiler and top up the lubricator all at the same time and you're good for another 30-40 minutes.  As I've said before though steamers really don't need to be hammered around the pond so take it easy and let the plant last for as long as you can stretch it out.

[Underpressure]

Great reply Bunkerbarge, you make and defeat the same point  

I am only considering a tank (or tanks) because the engine has a pump fitted as standard, but as you say, if the oil and separator need tending to after 30 minutes, then carrying enough water for 2 hours is a little pointless. I accept that once full, the boiler and water system can be forgotten for several hours and that topping up the water tanks is easier than topping up the boiler in the conventional way, that ends up being the crux for me.

Truth be told, I have always intended to fit a tank, but I was interested to see what you guys thought. Doing a few measurements today, it would be easy to put a pair of tanks below the water line and along side the boiler. These could be linked and a common feed taken to the pump, so I will do a little work in that direction before I decide on the final layout.

It is interesting to work through the system though, water, oil and waste, lastly of course battery duration of RC gear. There is always a limit and always a method to overcome that limit, but in the end, how long do we really want to sail for?

As for speed, I've always tried hard to make my models look realistic, knowing full well that I have a little in reserve!

[Bunkerbarge]

I wasn't trying to make a point merely give a number of options, many of which require different operational philosophies and can be adapted to suit your own requirements.

[HS93 (RIP)]

when Mr. M. J. Porter did the 24 hour he had a hand pump on a board and a water tank, they used a quick connect to the clack and filled when req no pump or tank on board a simple setup that worked well, it was a very nice baot to sail I had a few plays with it and bought a mouldings set as it was a nice simole boat with bags of room inside



http://www.deansmarine.co.uk/shop/product_info.php/cPath/26_33/products_id/503

Peter

[Underpressure]

when Mr. M. J. Porter did the 24 hour he had a hand pump on a board and a water tank, they used a quick connect to the clack and filled when req no pump or tank on board a simple setup that worked well, it was a very nice baot to sail I had a few plays with it and bought a mouldings set as it was a nice simole boat with bags of room inside



http://www.deansmarine.co.uk/shop/product_info.php/cPath/26_33/products_id/503

Peter

Peter,
       the team that ran that boat in the 24 hour Tone Valley event were: Mike Porter, Ian Holland, Jerry Watson and myself. I still have some photo's here of the event, it was great fun.

[Underpressure]

I wasn't trying to make a point merely give a number of options, many of which require different operational philosophies and can be adapted to suit your own requirements.

Much appreciated Bunkerbarge, options / opinions are exactly what I am looking for.

The trade off is extra complication vs extra running time and whether I actually need either.

While I am at the planning and build up stage, it is pretty easy to try out different options and configurations and decide what is going to add to the model and what is just ballast.

[Bunkerbarge]

That's exactly the thought process I have recently been through and, driven by the wish to bring the model in every half hour anyway, I couldn't see the need for automatic boiler level control and a big on board tank.  I went for a relatively small tank that I can top up as I feel like and then transfer it to the boiler with a hand pump.  At the same time I will top up the lubricator, empty the separator and bring the boiler back up to steam with an external gas tank before topping up the gas tank as well.

That's the theory anyway!!

[kno3]

In this case, the simplest and cheapest method of refilling the boiler under pressure is the one Regner offers for their steam locos and marine boilers: adding water with a special clack valve via flexible tube from a plastic pumping bottle.

[Underpressure]

In this case, the simplest and cheapest method of refilling the boiler under pressure is the one Regner offers for their steam locos and marine boilers: adding water with a special clack valve via flexible tube from a plastic pumping bottle.

SVS used to offer a similar system, in fact I have the special pump / bottle around here somewhere.

I know Mike Legg retired, but are SVS plants still made? Neat little engines.

Yet another project that needs finishing 

Still, the parts arrived from Jerry Watson today, to rebuild the safety valves on two plants, and the bits are starting to come together for the big tug, so it's all moving ahead nicely at present.

[gondolier88]

Washing-up bottle upturned with the bottom cut off- silicon tube to a hand feed pump from the squirty nozzle- feed pump to chck valve with rigid pipe- 'simples' as a certain well known meerkat would say!

Greg

[Underpressure]

Washing-up bottle upturned with the bottom cut off- silicon tube to a hand feed pump from the squirty nozzle- feed pump to chck valve with rigid pipe- 'simples' as a certain well known meerkat would say!

Greg

Ahhh, now you're getting to MY level of technology.

Neil