TheRcModelBoatForum.com
Please login using your username and password to use the forum.

If you do not have an account please register to participate, it’s free!
TheRcModelBoatForum.com
Would you like to react to this message? Create an account in a few clicks or log in to continue.


https://www.thercmodelboatforum.com/
 
HomeHome  RegisterRegister  Log inLog in  
 

 Steam controller

Go down 
AuthorMessage
Plymouth Sailer
Deck Hand
Deck Hand


Posts : 3
Join date : 2020-08-14

Steam controller Empty
PostSubject: Steam controller   Steam controller EmptyFri Aug 14, 2020 6:30 pm

Hi, I'm still fairly new to steam and several things puzzle me. So your help and advice is sought.

I have a Chinese twin Vee engine and the regulator has four connectors. Obviously one is input, two is to the right cylinder and three the left.
So logic tells me that the fourth outlet is redundant and of no use.
Am I correct in this ?

Also the engine runs beautifully on compressed air at low pressure, but as soon as I introduce steam it doesn't want to know.
Steam seems to escape from almost everywhere and as a result I cannot get a working pressure in the boiler, or enough to blow the safety valve.

So any comments more than welcome. Thanks in advance.
Back to top Go down
Roadrunner
Forum Overlord
Forum Overlord
Roadrunner

Posts : 1664
Join date : 2011-06-10
Location : Aberdare South Wales

Steam controller Empty
PostSubject: Re: Steam controller   Steam controller EmptyFri Aug 14, 2020 11:42 pm

I know enough about steam engines to know the chinese ones need a lot of work to run correctly... ( or remade
Parts.. sorry to say but there’s a reason those tend to be half the price and it’s half the quality!)

Porting Varys.... it’s usually 2 in 2 out... but they work top to bottom for the most part on ossolating.. ... unless it’s a slide valve then It’s shuttled in the steam chest... It could be reverse function.... 

I would strongly suggest some reading to understand steam engine basics... that includes porting.. you won’t have a “redundant port it’s there for a reason... believe me there are a ton of books out there to help and explain what I say next.....

Most steam engines kit ones of top quality tend to still require some work to reduce leakage but they will always leak!... compressed air running and under steam pressure are two totally different kettle of fish to compare... most people test engines on compressed air before heating it to 100degrees...

So you will need to seal Around ports, water level gauges, ( never use bloody silicon sealant... EVER) wrap the pipes in string and super glue to reduce condensate. Set the safety valve to half pressure to start and build it up to required limit... and then look into lapping the port faces... steam oil is required as lubrications as well as able to aid in sealing... Watch out for cold starts and hydrological lockup’s... ( engine killers) 

Lubricator fitted? 
Condenser fitted?
...

Huge tub of Vaseline Handy?

My advice... stop read learn and fix the basics before re-firing under pressure... burns and blown boilers are deadly! Remember you can’t see steam until it’s stripped your finger to the bone!.... 

Maybe search YouTube for one of my steam fixes “Keith Appleton” Either that or hope my old man logs on and sees this, he’s the true expert I turn to for steam advice
There are really to many things to list and check i would have to write a book here to help give you hints and tips on what “could” be going on...

_________________
I'm  Not  Anti-Social,  I'm  Anti-Stupid.
Back to top Go down
https://www.thercmodelboatforum.com
Roadrunner
Forum Overlord
Forum Overlord
Roadrunner

Posts : 1664
Join date : 2011-06-10
Location : Aberdare South Wales

Steam controller Empty
PostSubject: Re: Steam controller   Steam controller EmptySat Aug 15, 2020 12:30 am

Ok that sounded rather grumpy.... I’m just going to shrug of the warnings on that... when I first started messing with steam I got a book before I got the engine... and believe it or not my first home built engine came out of this book and still today runs flawlessly... I actully have an upcoming log due on a full slide valve engine build now I have my new lathe, I would highly recommend buying “model marine steam , by Stan Brav” I have many other books on steam but that was my first and from that I was able to get a working steam engine built from scratch with zero prior help... then my old man told me I was a total twat... and then stole the engine for a year.... 😀 lol!

I’ve not actully seen this engine you have so I can’t comment on its quality but it’s a fair assumption it’s not up to standard yet to be useful, basics usually missed by novices are how the ports function and how to get a good seal on the port faces... this tends to be the no1 place of epic leakage.. those faces require almost perfectly lapped facing... this is a lot of manual work with lapping paste to get them DEAD flat to each other... the stream oil from the lubricator is picked up on steam input, and flows around the piston and ports to help seal it off, the condensate is on the exit to pull the oil out of the steam return... and the remaining steam pumped up the chimney... I’ve seen some boilers use back pressure from the return too... don’t quote that as a fact... I’ve seen many custom engines And boilers over the years many built and modified in ways that are truly scary...

Boiler pressure should be built before it starts the engine, you should be getting full pressure before kicking over the flywheel to start, which means you need to find every leak and fix it, “plummets mate” Vaseline, kY jelly all good for specific seals, check your water lvl gauges “o” rings micron to loose that glass is gonna piss everywhere and you’ll never achieve pressure... 

Like I said it’s a book into its own on what “could be” wrong and list of fixes is as long as my arms and legs combined unless you have extensive knowledge on how engines work...

Compressed air is easy.... engines always run becuase it’s a safe and constant steam of air regardless of leaks... it’s also larger “partials“ then steam which can find its way outta anywhere so much easier especially under pressure! 

Steam is also invisible until it hits the cooler air and condenses... so you can get a very nasty burn very easily on a leak because you can’t see it until it’s to late... pressurised steam in a sealed system is NOT like a boiling kettle!... that one I learnt years ago when I got my first job in a factory running steam moulding machines for polystyrene. So be very aware!!! 

Pressuring your boiler is also a nasty affair if your not careful, the trick is to get some pressure and set the valve then reset it as you increased the pressure to working pressure... better to start low and build then max it and watch it go off like a grenade... and yes it happeneds!!!!! A LOT more than you think...

Hydraulic locking happens on a cold start,, you normally need to clear it as you start up the engine.. condensed steam can build up in the piston and it takes a easy light turn or two to clear before the hot steam takes over and pushes it back through.. that moment of tightness can break the piston or both in a fraction of a second if your too heavy handed on turning it over.. if it’s locking out wait for it to get hotter and then flick it over.. 

All engines have their own personality yours you will need to learn, some hate cold starts other love them.. some don’t leak for a good while then piss everywhere others are seal monsters... run times vary too some engine like long runs others 10-15 mins the. Want cooling ... which leads me to say that you never want more fuel in your boiler than than water you carry... absolute rule
Of thumb... You should run out of fuel before you ever run out of water!!! This rule if it’s the only one you follow is the one that saves your boiler never burn a copper boiler dry EVER.

_________________
I'm  Not  Anti-Social,  I'm  Anti-Stupid.
Back to top Go down
https://www.thercmodelboatforum.com
Plymouth Sailer
Deck Hand
Deck Hand


Posts : 3
Join date : 2020-08-14

Steam controller Empty
PostSubject: Re: Steam controller   Steam controller EmptySat Aug 15, 2020 11:13 am

Thanks for a comprehensive reply[url=https://servimg.com/view/20250411/1]Steam controller M2b_en10
Steam controller Dscf0310[/url]

The engine in question is the microcosm M2B. It certainly feels substantial. It is in pieces due to the fact that the Banjo screws attaching the controller to the block were crap and one snapped. Microcosm now make them from stainless steel but I can't get any sense out of them when try to order replacements.

Photo 1 shows the complete model as supplied. I have disassembled the valve and it is simple in that the input steam is channelled either left or right. There is no connection to the outlet opposite the input, hence my thoughts that it was redundant.

Photo 2 is more of a closeup (not sure if this will help any).

On thinking about it. It must exhaust the spent steam somewhere, so this must be the reason. So I seem to have answered my own question on that.

I have the book you refer to and was encouraged by the fact that he thought  this configuration was so simple little could go wrong.

Any suggestions as to the best lapping compound. Clearly this process has to be carried out on the bench so I'm guessing that its apply the paste and work the cylinders by hand until satisfied that they are a 'dead' fit.
Back to top Go down
Roadrunner
Forum Overlord
Forum Overlord
Roadrunner

Posts : 1664
Join date : 2011-06-10
Location : Aberdare South Wales

Steam controller Empty
PostSubject: Re: Steam controller   Steam controller EmptySun Aug 16, 2020 4:09 pm

ok looking at that engines configuration its pretty much the same as a basic ossilator, just in a V configuration.  just a note anything Brass will always  'feel substantial' brass is a very heavy metal just one of the softest to machine (think shiny lead)  brass is used for the most part in steam engines as it is easy to machine, and heat condution tends to help them as brass dose not ' expand and contract' when heated > its rather stable under extreme heat and cooling phases 

You have the main imput with the steam oil resiovoir attached to the valve > which is reverse fuction > that is channled of the photo to start to the left piston> steam in through left > up through right > then exit to the ' redundant outlet' that central exit facing you is required to be attached to a condensate tank/ steam oil catch > from there its stright out exit to atmosphere

The valve is moved probbaly 90 degrees forwards on that to send steam the other way through right piston then up left and exit >... 

So leaking on the port faces can be reduced with the screw and spirng holding the pistion in place just screwing tighter but not so tight the pistion cant move > you have a bigger problem here, these type of single sided bolts work but cannot hold the pistion tight to the steam chest, you will always get a lot of leakage.

Steam controller 0f4d7910

most ossilators have suport on the opposite side of the piviot as support, the image above shows my dads the piviot is central through the steam chest to each pistion and the tighting screw is retained through the guard wrapping the pistions.

this image also shows the same configuration you have accept port Entry.... your port entry is done via little ball joint type tranfer sockets where we on this engine its directly under the valve lever

Steam controller 971e0810
Steam controller B6245010

the LARGE open brass tubes on the base of the central steam chest and the shaft exit is actully an oiling cup for lubritation of the shaft.

Lapping pastes vary... first off you need to see how far off the faces are, lapping paste can only do so much if the orginal surface is badly machined and not actully flat to each other, then you'll need to have it machined flat on a mill first then lap it.... trust me if you tell a bad face the gaps around it will be substancial in places usualy on one edge... 

There are many brands of laping compound out there just find the one in your budget and the finest grade or look on engineering forums for suggestions. i honestly havent got one to recomdend as its been eons since i messed with an engine.

all said an done if you get it all right the outcome should work like this...


_________________
I'm  Not  Anti-Social,  I'm  Anti-Stupid.
Back to top Go down
https://www.thercmodelboatforum.com
Plymouth Sailer
Deck Hand
Deck Hand


Posts : 3
Join date : 2020-08-14

Steam controller Empty
PostSubject: Re: Steam controller   Steam controller EmptySun Aug 16, 2020 8:08 pm

Many thanks for all of the information.
I can see that I will have to rethink my source of steam equipment and no doubt spend a bit more for more satisfactory results.
Back to top Go down
 
Steam controller
Back to top 
Page 1 of 1

Permissions in this forum:You cannot reply to topics in this forum
TheRcModelBoatForum.com :: Modelling Categories & Archived Build Logs :: Live Steam-
Jump to: