Garden Railway Forum

Hi all, Does anyone have any information or has completed a scratch built de winton using a mamod cylinder? If you have would you mind telling me a bit about it (what materials were used etc) and in particular the reverser used. I think some use a mamod one but as it only has one cylinder im not sure how that would work where as others use a more accucraft style one. I understand that the one axle needs to have a u shape i think but would like to know more
cheers
Joe

Ive built a dewinton using a single Mamod style cylinder direct drive to the front axle.



I built it back in 2008 from scrap basically. The frames are made from thin aluminium plate with brass bearings pressed in for the axles. This was also used for the foot plate and bunker / backsheet. The axles and wheels are from accucraft, the rear one being unaltered. The front one was altered to have a crank in the middle for the cylinder to drive. The boiler is made from brass tube with two discs soldered in and a flue up the centre. the most complex item is the engine frame that is a fabrication from brass plate and bar. Its meths fired, the tank carried under the driver.

It was the first loco I made and although working is very flawed. Aluminium is a terrible material for frames, far too flexible. The boiler should have flanged plates and be silver soldered but most important not brass ! Possibly the biggest mistake was making it internally fired, this means the exhaust is used to draw the fire. As there is no blower the start up is rather complex and the engine can't stop running or the fire goes out. It also has the added side effect of sounding like a BBQ while running.

Dave Watkins steam website (google it) has a good write up about Idris a Dewinton type engine. While it does not use mamod cylinders the idea could be adapted.

Thanks guys, what materials would you suggest making the frames out of then? obviously the boiler needs to be copper and ive heard it helps to add a long chimeny

Frames should be out of steel really but brass can be used in these scales. Addind a long chimney only helps when you get up to larger scales to help draw the fire while the engine is cold.

DLRdan:109677 wrote:Ive built a dewinton using a single Mamod style cylinder direct drive to the front axle.

Very nice Dan!

Best wishes,
David.

Joe i recommend Dave watkins design for idris if you want to scratch build... if you already have the cylinder then look at how to design the frames and the driving axle, make the frames from steel and boiler from copper (flanged ends and use silver solder as dan said) and work out how you wish to fire the loco. a meths burner is likely the easiest and you could adapt the design provided by the Idris drawings to run a mamod cylinder....

It is worth noting that a single ocsilating cylinder has to run quite fast in order to retain the motion, running a pair of cylinders will smooth this out and slow running can be achieved. adding gearing to an ocsilating motor is a further option for high torque and low speed but you then have to look at availible space.