Reversible, double acting single cylinder engine


Length o.a. 80mm
Width o.a. 44mm
Hight o.a. 78mm
Wight 350g
Diameter crankshaft 4mm
Hight centre crankshaft over ground 11mm
Type of valve Piston-Valve
Type of reversing gear Button-Type Reversing-Valve
Working pressure 1 – 2 bar (15 – 30psi)
Bore 12mm

Number of cylinder

10 mm


  • GEM TM1 is suitable for 4-blade-propellors with diameter from 50mm – 60mm
  • The GEM TM1 engine is available either as a „ready to run“ finished engine or a completely machined kit for self assembly, no soldering required.

Our GEM TM1 is a true innovation! The worlds only fully reversible and self-starting single cylinder-engine. Even when fully stopped GEM TM1 will always restart, guarantied!

If you had always wished to build a proper scale model of the famous „African Queen“ or of a similar steam boat, GEM TM1 is the perfect engine for such a project.

The handling of the engine is very easy because you require only one servo to have full control over over all aspects of running the engine like regulating the speed, stopping or reversing. This makes this engine particularly well suited for models with twin propellors but also for smaller models with a displacement starting from about 3Kg (6 – 7 lbs).

With this construction, as with all our other products, we took great care to achieve durability and robustness. The all-steel crank-shaft is running in 4 solid brass bearing-blocks, piston-rods and piston-valves are made from from stainless-steel, excentres, cross-heads and the four columns are made from steel. All other parts are machined from brass.

With its four slender steel-columns the engine has an aspect of lightness and grace which makes it a perfect fit for the engine-room of a classic steam-boat model.

GEM TM1 Grafik Dimensionen englisch

GEM TM1: Finished engine, ready to run:

  • The finished Engine is delivered with chemically blackened cylinder-blocks, reversing-valve block and base-longitudinal’s, all other brass and steel parts are polished.
  • English operating instructions.
  • Displacement oiler and reversing-system are included.

Price GEM TM1, finished, ready to run:

G01 GEM TM1:     CHF 980.–


GEM TM1 Machined kit for self-assembly

  • The kit is completely machined, all (metric) threads cut.
  • Surfaces are ground or, in areas to be painted, sand-blasted.
  • No machining or soldering required.
  • The columns, each consisting of four parts, are delivered pre-assembled.
  • What needs to be done is a light chamfering of sharp edges, and, if you want to, a bit of polishing and painting.
  • Step by step illustrated building-instructions in english make building the engine easy.
  • Displacement oiler and reversing-system are included.

Price GEM TM1, Machined kit:

G02 GEM TM1kit:     CHF 860.–



If desired I can built a complete steam-plant for you, according to your requirements.
For more information please click here:

Anlage JADE Anklick-Bildli

All prices are given in Swiss Franks (CHF).
Shipping costs are not included.
Also not included are any duties and taxes due outside of Switzerland.