Some help needed

[Dodo-steam]

Hello everyone just joined and I hope this is the right section to ask this question in. My main hobby is playing with RC cars and recently I have gotten an itch to make one steam-powered and the one thing I am finding the hardest to build around is the boiler. At first, I was looking at a fire tube boiler design and recently found out about the monotube boiler design. Keep in mind I never build anything steam related but I would appreciate some input as to which boiler you guys would recommend, very limited in space to around 150mm in length, 50mm in width and height isn't limited so much as I can run the RC without a body. I could play with those dimensions slightly as I can always grind away some of the material of the chassis but not much.

 

[BaronJ]

Search "Flash Steam" add the word Boiler at the end for more hits.

 

[fcheslop]

This link may answer a few questions
Discovering flash steam

 

[Dodo-steam]

Thank you for the recommendations, one of the articles I came across in a google search mention a book called
Experimental Flash Steam, would this be a recommended read for learning more about monotube design.
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[fcheslop]

The book is a little old but still a good starting point
This French site has a few simple flash boilers
http://www.vapeuretmodelesavapeur.com/groupederubriqu13/index.html

 

[Dodo-steam]

Thank you, good reference point I eneded up ordering the book found a cheap copy for 10 dollars hopefully it helps me learn more on the subject. Just a quick question I already been told by a local the downfall of steam turbine in a small scale like this no starting torque, steam hungry, etc. Any other downfall in the steam design for an application like this? keep in mind this rc typically weight 1300gram ready to go when battery power I estimate one that is steam power would easily be in the high 1000s gram mark tipping
into the 2000 gram.

 

[fcheslop]

Sorry Iv never used a turbine other than building one for fun and it was greedy for steam and lacked torque on start up
Iv only used a uni flow type steam engine for flash steam model boat
You need to consider the temps involved when selecting an engine design as my last one would burn out hardened and hard faced inlet valves with regular monotony
This link may help

 

[Dodo-steam]

Just finished watching the other parts of the videos thank you once again fcheslop good info in those videos. I also came across this thread talking about the efficiency of different types of position model steam engine and it mentions compound being the most efficient ones, I was looking at a double-acting oscillating engine due to its simpler design but if the efficiency is that big maybe compound is worth looking into. Any thoughts?

 

[fcheslop]

For small sized compound engines two things come to mind condensation losses and in general they are not self starting .They can be made to self start but its another addition and another thing to go wrong when using RC
I doubt an oscillating engine would like to run on super heated steam for very long or like the pressures involved.
I use simple twin double acting oscillators in my semi scale boat builds and find they like lower pressures and wet steam. They generally run at 15 to 35psi.
In my true scale builds the engine look like a compound but are simply double acting twins or triples
Flash steam in general tends to be an on/off thing as in its either flat out max revs or a sulking mess not many have built systems to control speed . I do remember a build on Model Boat Mayhem Flash Two who build a controlled system using some reasonably complex electronics to monitor several feedback loops
My choice would be fore a simple twin piston valved engine with a vertical multi tubed boiler of small capacity with an engine driven water pump it will depend how big,fast you want this car to go
Iv been thinking of building a Morgan 3 wheeler with a V twin Stirling engine for some time just need to finish some other bits of first
Here is a link to a wee video its not the boat thats interesting to me at least but the rather clever drive system
Well thats my two bobs worth and all this one fingered typist can manage
cheers
frazer
Le "Stirling tug" de Daniel navigue - Atlantica Steam 2014 RC 15 - YouTube

 

[Dodo-steam]

That video gave me lots of ideas for a possible future build. Specially thr drive system design. The first engine I was looking at was the PM Research Steam Engine #8 but 2 problems came up low RPMs(250 to 1000) way too low for RC i could use a gearbox but that would make the 2nd problem worse which is weight they quoted me at around 2 lb for it. So right now I am looking at the TVR1ABB in their manual they say it is good for 3800 to 4000 max rpm and weight around 325grams. As for the boiler I am still seeing and research all the different designs. I would like have a boiler that has the water tank and heating coil apart driven by a small water pump to better balance out the chassis but still just researching. Do you have any link or plans to engines similar to the one you suggested? Most steam engine plans I come across seem rather large. Twin piston engine around the size that saito make like the t2dr is around my limit for engine size in this chassis.

 

[fcheslop]

There are a few smaller designs knocking about Malcolm Beaks MB22 is a nice runner and punches above its weight
Also a small German piston valved V twin that Julius Dewaal redrew at twice the size
This site has some designs for free including the larger V twin and there was a build on here for the original small version
steam and steam models
A wee video of the MB22 ticking over its 3/8 bore and stroke double acting twin and will have a reverse gearbox fitted when I get round to building the boat.The boiler Im not sure at the moment either a simple centre flue or a vertical fire tube job


A wee video of a small steam plant wobbler for a 12inch long Clyde Puffer. This was just a few ideas pinched from here and there stuck together and very simple

 

[Dodo-steam]

Well, the motor has been picked I have an older saito t2 coming my way. Finger crossed it is a good match.

 

[Dodo-steam]

Just some more quick question, but currently working on the burner. Still, haven't decided on a gasoline/kerosene style type blowlamp or a gas power one. For the gasoline/kerosene burner has anyone ever done a pump driven one instead of a pressurized one?