Feinmechanik in Perfektion - handmade in Germany
  • 180ccm SM
  • 350ccm SM
  • 700ccm SM
  • 1. Generation | 9-Zylinder 180 ccm
  • 2. Generation | 9-Zylinder 350 ccm
  • 3. Generation | 18-Zylinder Doppelstern 700 ccm

Heilemann Sternmotoren - Success Story


Elke and Andreas Heilemann

Dear visitors,

the development and building of radial engines was born out of necessity. Being a passionate model airplane flyer I wanted to build a Boeing Stearman PT17 on a scale of 1:3 in 1990. Of course the motor should be a 9-cylinder radial engine, just like the original. At that time it was not possible to buy a 9-cylindrer radial engine suitable for this size of model. I had already converted two-stroke engines from conventional chain saw engines to model airplane engines. So I decided to build the radial engine for my Stearman myself.

My firm belief was: One who can convert chain saw engines, should also venture on four-stroke engines. But far from it!

So many years passed with endless attempts, failures and improvements. My friend Peter Haag, an equally passionate engine builder, actively supported me.

Fortunately I have a wife that accompanied this path understandingly.

During a development period of 18 years emerged first a 9-cylinder radial engine with 180 ccm and hereinafter, as further development, a beautiful 9-cylinder radial engine with 350 ccm. For the development of this 350 engine I brought in all my experience of the previous years. The result is an engine for hard daily use in a model airplane. Very lightweight with high reliability, long-lasting and low-maintenance – no engine for the cabinet. Against the trend of the time I always build methanol engines. For a safe flight I accept the higher consumption of a methanol engine. When a radial engine is running, theoretically only the heat plugs can fail, but hardly all nine at once. It starts up very well, can be started manually and has a silky smooth engine operation in all speed ranges at an operating temperature of 110-130°C (230-266°F). As I can do without adding nitromethane to the fuel because of the design of my engines, there are no corrosion problems.

The development continues. Currently an 18-cylinder double-radial engine is being tested. The first test runs were very promising.


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