Andreas Heilemann (née Beck)	Elke Heilemann
The constructor, test pilot and boss	The control center

For me to develop and construct radial motors was acting from necessity. I am a passionate model airplane flyer and in 1990, I wanted to contruct a large bi-plane on a scale of 1:3. The power engine was supposed to be, of course, a 9 cylinder radial engine. At that time, one could not buy a large 9 cylinder radial engine with approximately 150 – 220 ccm. As I am a trained steel construction mechanic in machine and vessel construction and as I was already building a two-stroke gasoline engine made from common chainsaw engines, I decided to construct a radial engine myself. I was convinced that someone who could build a two-stroke engine could also construct a four-stroke one. Far from it!
Luckily at that time I got to know and esteem my now long-year friend Peter Haag, without whose know-how and help would have not made all that possible. He had already developed and constructed two radial engines on his own account. Only manually lathes and millers were used in his well-equipped garage.
Years went by with endless tries, improvements and failures. If only I had known what was coming up, I probably would have kept my fingers away. Luckily, I have a very understanding woman that joins in (almost) everything and supports me

Our pilot and flight guest	My first 9 cylinder radial engine with 180 ccm

After 18 years, a wonderful 9 cylinder radial engine with 350 ccm was developed and constructed, which inhibits all my whole knowledge and experience. It is a continuous development of my first 9 cylinder radial engine with 180 ccm. Constructional scarcities, which have been recognized along the years such as the leakage in the engine air intake, the wear of the cam and valve gear, mounting difficulties, intermittent failure of the lower cylinder have all been redeemed from the new construction of the 350 ccm.

This trial crowd consists of: magnesium alloys, titan alloys, diverse coating and material trials. One time too soft, then again too hard, the compound between the materials was inappropriate.

Trials, tests, trials, test, trials …
This is what you get if you can’t work with compromises.
A lot of learning the hard way!

I never wanted to construct an engine only for showcase. I wanted an engine for the hard, daily use in model airplanes. The concept for the construction of my radial engine was suitable for daily use, to be started manually, no afterglowing after start, reliable, very light, long-life expectancy, low-maintenance needs, no gasoline but methanol (easy handling and few failure sources). I rather chose save flying instead of lower mileage. If the radial engine is running, the heather plugs could turn out theoretically but all nine at a time actually not. It starts very quiet and has a soft operation at all speed ranges. As I am a model airplane flyer myself, I dainty paid attention to the realization of my concept and did no compromises.

The thought that the engine could break while flying due to some neglectfulness during construction, leaves you working very carefully and exactly.
The exposure to a 9 cylinder four-stroke radial engine demands a little technical understanding and care. However, it is possible for everyone!
Even if an engine is suitable for daily use, I started to make an optical inspection after each flight to check whether something dismantled or cracked.
The power of my engine is not indicated in PS since I have no dynamometer with a performance brake available.  Anything else would be speculation. The indication by static thrust and propeller is much more meaningful.

My 9 cylinder four-stroke radial engine 350 ccm flies in a Boeing Stearman PT17 on a scale of 1:3 from Balsa USA.

It consists of over more than 900 components, that intertwine with eachother as in a Switzerland clock and that provide a good and safe flying feeling.

If you have questions to your radial engine, please contact us. You can find our contact data under “Contact” .

Consultation regarding a change in the drawing with one supplier out of my eight suppliers in total.
Weighing on a precise bench scale of the company Soehnle Professional . The weight measurement on a personal scale would be far to inaccurate for me. Thanks a lot to the team Soehnle Professional for the support.