Sentinel Steam Shunter plans

[yorkshireman]

Question for a friend in Germany:

Are there anywhere plans for a Sentinel Steam Shunter available?
Preferably in 7.25...

Thanks
Johannes

[mutley]

Hi Yorkshireman
I believe a design was seralised in Model Engineer in 1961.This was for 5" gauge but you could scale it up. Mike at Station Road steam had one many years ago you can see it in his archive here.
www.stationroadsteam.com/stock%20pages/2654/index.htm
Very simple and used a Stuart Turner for the power plant.

Andy

[kingsteam9]

It was indeed, and named 'Sirena', described by J J Constable. His example won the Championship Cup at the ME exhibition if I remember correctly. Serialisation started in ME in 2nd February 1961, vol 124 issue 3108 and ended 21st December 1961. I've part built a 5" gauge one but the series contains quite a few dimensional errors and so for the time being it's on the back shelf while I sort out the workshop machinery, and until time is available to redesign bits. JJC's original boiler design is complicated by the use of inclined tubes, but I plan to use a version of Robin Dyer's Clayton vertical boiler adjusted to suit, and which is a imore straightforward to build.

Robin

[eightpot]

I built one 25 or more years ago with a few mods. From memory the chassis and boiler are as per JJC's drawings, but found it necessary to replace the top (?2 on the front, ?3 on the rear) tufnol spring leaves with spring steel ones due to the weight, especially of the boiler. A bit of variation of fittings, particularly the steam take-off on the boiler top as it primed badly. Made this much larger, around 5/8" diameter thread, larger bore and belled out at the threaded end to spread out and slow down the steam flow. Engine - managed to get St's to specially cast gunmetal cylinders for me, being concerned about limited use and corrosion. I made new valves with longer laps (had to cut-away the portface side of the valve chest to accommodate), using half-size 'Juliet' drawings and with half size versions of the Stephenson link valve gear. Also drain cocks were fitted and a tundish to collect oil spill under the engine to let oil out on to the middle of the track. Due to the steam and exhaust pipework condensation is a problem when starting off, so a 'diverter' valve was fitted at the end of the exhaust pipe where it came back into the cab, in the 'dump' position the condensate goes down a pipe to below footplate level. This is only needed for a few seconds from moving off. The reversing lever is a single pole type which is pushed down to disengage the lever from notches on the underside of the sector plate. For firing on the move I made a glorified tapered and larger diameter 'funnel' with a spring operated lid that fits in where the stoking shoot would normally be. Performance - not a 'heavy-hauler', but once you have started one can soon notch up and it accelerates away. Hope this is of help.