Updated: 30-Apr-2026
In 1995, Ralph O. Watson built a 7-cylinder rotary radial engine with two pushrods per cylinder, one for each valve.
- It produced 60 HP at 1,400 rpm. Its displacement was 5113 cc (92 x 110 mm).
“Two views of the Watson”
Arquitecture:
Cooling:
Total Displacement:
Bore / Stroke: x
Power:
Weight:
The author of this edition of Aeroengines AtoZ, through Aeroteca, collaborated on Version 2 of this video, which is presented here.
To understand the operation of the connecting rods, the 1929 Continental R 670 single-cylinder engine was chosen.
A demonstration of Version 3, improved at the author's suggestion, is also available on YouTube at a later date. This version shows bronze valve guides, improved valve spring movement, and the split crankshaft counterweights and front bearing balls also move.
The design is from Juan Soler, Sant Cugat, Barcelona
Below we show a flash of version 3
Counting also with the coloboration of JMC of Enginys Mecanics in Mataro, Barcelona