The Swiss carpenter and the Bavarian mechanic decided to test the theory with practice …

Willy Ruffenaht and Rupert Bindl were united by hobbies: both are passionate fans of motorcycle racing and are known among like-minded people for their engines for superbikes. In 1997, they met and decided to implement Rupert's idea - to create a cunning twin-shaft engine. Theoretically, such a design was known back in the thirties, but for some reason (like, by the way, many others) remained unclaimed.

The advantages of symmetric construction are obvious. The inertial forces of the first order are balanced, moreover, without balancing shafts. This means that there is no longer such an unpleasant vibration. Two shafts, rotating in opposite directions, compensate for the gyroscopic moment, which is especially important for motorcycles. Finally, the piston is no longer pressed against the walls of the cylinders and therefore it can be made much shorter, lighter; wear of rings and sleeves is sharply reduced, as well as friction losses. That is the theory.

Another thing is that there are losses in the gears connecting the two cranks, and the number of bearings doubles. Interestingly, however, what will outweigh? The inventor friends went home and sat in their workshops in order to show the public two twin-shaft engines, vigorously rattling on test benches on the eve of the millennium. Swiss carpenter Willy after much deliberation and estimates in just three weeks, built a single-cylinder unit with a working volume of 125 cm. He cranked the crankshafts and the piston himself, ordered the block in the foundry according to his own sketch, and borrowed the cylinder and head from the Honda XL XL 125. The resulting engine in the first attempt spun up to … 16, 000 rpm and worked, worked, worked … Good luck inspired Willy - now he plans a two-cylinder liter unit with a capacity of at least 200 liters. with.

The mechanic from Bavaria Rupert approached the matter more thoroughly. From the very beginning, he intended to enter the market with his product, and not just check the theoretical postulates. Therefore, I had to order calculations to a special design bureau, and then, having received specific numbers, look for a sponsor for the engine. He became a realtor Peter Peltz, who laid out 150, 000 marks for the right to commercial use of the invention. It took almost six months to build a 750cc single cylinder engine, but the result was worth it. The experimental sample has a maximum power of 97 liters. with. at 9500 rpm and a torque of 77 N.m at 8200 rpm. Although losses in gears and bearings ate up to 10% of the power, the result was still a five percent gain compared to the analogue of the traditional design immediately in “three categories”: fuel consumption, power and torque. By the way, in this model the cylinder and head are completely home-made and also very original. Four valves are located radially, and the inlet channels, on the contrary, extend vertically between the camshafts.

Will solid engine builders be interested in new products? This question is still open. But the fact that already the first pancakes did not become lumpy inspires optimism.