At the New England Air Museum in the USA there is a radial engine, apparently rotary - it is not certain - due to the rear mast. There is no further technical data provided.
“The Sperlman not yet on display to the public”
-Looking at the cylinders, it is clearly a two-stroke engine.
Engines of SPERLMAN
Model: Radial engine
Arquitecture: Cooling: Total Displacement: Bore / Stroke: x Power: Weight:
Other details:
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