Stuart Sirius

[Richard Hed]

Hi Richard,
The Sirius was made as a generator engine, for a War Department order for Generators for re-charging batteries used for small radio sets, often dropped behind enemy lines, e.g. for the French Resistance, or troops or spies, during WW2. The boiler could sit on a wood fire, or any domestic stove, and looked like a domestic pressure cooker in a kitchen, as disguise! But I was once told you could cook potatoes in 5 mins in one! Tank crews had one to power/re-charge their radios in the field, for use with a petrol stove, so the story-teller explained. The generator set comprised the Sirius engine (weighed ~8lbs I think? You would know...) and a dynamo - stored inside the boiler! - Or so I read once... Dropped individually by parachute into France by the hundred, for French Resistance use...
The "Baby" of Sirius was the Sun engine, weighed 4 1/2 lbs., mostly made by modellers from a casting set, to power "fast steam" model boats, like torpedo boats, etc. after WW2. - I made a Picket boat to take mine, but it was too heavy. Now attached to a small generator, just to do something...
But model boat people wanted a smaller engine, ready made, so the produced the Star engine, that also had many parts in Bronze and Aluminium (Pronounced as above: Al-u-mini-um) and called the Star engine. Weighed 2lbs. Just right for my boat!
K2View attachment 164912View attachment 164913View attachment 164914View attachment 164915View attachment 164916View attachment 164917View attachment 164918View attachment 164919View attachment 164920View attachment 164921

Ha! That's right, there were three! The Sirius (that's the brightest star in the sky, to the left of Orion below his feets a bit), the Sun (that's also a bright star), and the Star! Are the Stars produced by anyone? I suppose one could cut one out of bar stock if one had the plans.

 

[Steamchick]

Hi Richard,
I understand (from maybe 15 years ago when I read about them, so check for yourself for an accurate answer):
Sirius, Castings as a kit with drawings, as well as finished engines, used to be available from Stuarts - only a few years ago when I last noticed - who made the Original engines.
Sun, 3/4" Bore and stroke, single acting twin, 180 degree crank. Cast Iron parts. Originally from about 1953??: original date on my Stuart drawing 90006+ by J.H., but this supercedes Drg. M140 - so I don't know the earliest engines. - Maybe from the 1930s? My castings were a second-had kit bought around 2000, but had been originally purchased from Stuarts in the mid-1960s (1964 latest revision of drawings, and I found 3 or 4 dimensions that didn't fit!).
View attachment 1740031012294.jpeg
I didn't get con-rods, bevel gears, and flywheel casting, but other parts and castings were there. Max. revs. 2000rpm. It could be scaled and made from bar stock. I should consider an Aluminium block and head, with bronze cylinder liners and aluminium pistons. and a stainless steel piston valve rod. Instead of the large loop (steel pressing) for the valve rod con-rod, I should use levers, and incorporate a reverse mechanism, if I made one from scratch.
Star: 1/2" Bore and stroke, single acting twin, 180 degree crank. Cast Aluminium block, Phos. bronze crank and con-rods, etc. parts: Never available as a kit, or parts, or drawings. Only sold as complete engines. (As far as I know). I have only ever seen 2 on £&@y! - and bought one! Well used and worn, but still a runner.
K.N.Harris in his book "Model stationary and marine steam engines" has a similar design "Twin cylinder enclosed single acting high speed single valve steam engine" Fig 20. Scan attached but "Not for any commercial gain".

Copyright Percival Marshall 1958. Hope this is of interest?
Cheers.
K2

 

[Jasonb]

All three were available from 1928. The Star upto 1941, The Sun upto 1990 and you can still buy the Sirius castings.

Then there are the similar layout MTB range which had 5 engines of various sizes

I've got the early stages of a MTB 1B drawn up with a view to scratch building it. Not drawn yet are the bevel gears which are exposed at the front so a bit more interesting than having it all hidden away. Will be done in metric as we don't say inches here much either

 

[Richard Hed]

All three were available from 1928. The Star upto 1941, The Sun upto 1990 and you can still buy the Sirius castings.

Then there are the similar layout MTB range which had 5 engines of various sizes

I've got the early stages of a MTB 1B drawn up with a view to scratch building it. Not drawn yet are the bevel gears which are exposed at the front so a bit more interesting than having it all hidden away. Will be done in metric as we don't say inches here much either

Ha. Would very much like to see your development. Particularly any of the larger models. To me, it's very curious that the Sun and the Star are NOT out there for purchase. Of course, it's always because there is no interest and the producers certainly are not going to make things that don't sell. But these little engines are really highly developed steam engines that deserve a place along side all our other models which show old and developing technology from a bygone era. What is an "MTB"?

 

[Jasonb]

Marine Twin Boat

Have a read here. Also look under the "marine" heading for more detailed descriptions of each

http://stuartturnersteam.com/Marine/MTB/MTB.html

There arr very few who would want to build any of these as working boat engines these days so sales would be small and not worth stocking and possible costs if the patterns have not stood the test of time and need reworking.

 

[Richard Hed]

Marine Twin Boat

Have a read here. Also look under the "marine" heading for more detailed descriptions of each

http://stuartturnersteam.com/Marine/MTB/MTB.html

There arr very few who would want to build any of these as working boat engines these days so sales would be small and not worth stocking and possible costs if the patterns have not stood the test of time and need reworking.

Yes, I suppose you are absolutley correct. Since I am not into boat modelling or engines specifically for the purpose of putting them in boats, I would not know about their popularity. HOwever, as a model maker, I AM, indeed, interested. Thanx for that link, it is the first time (I thimpfk) that I have seen that page on those engines. Intriguing. Anyo9ne know of possible plans for any of these?