Helium made a two-stroke rotary engine with three cylinders and double-acting pistons in order to force the cylinders sweep. The working and sweeping pistons are joined and the connecting rods articulate below the latter.

“Helium”

-Around 1910 there was the 2-stroke, 5-cylinder Helium radial engine with double pistons. It gave 100 CV at 1,200 rpm.

-A brand from which we have discovered much more activity than we assumed in the main text.

“Logo Helium”

-These engines work with the two-stroke cycle, and they have a double piston. One is the working piston and the other one sends the mixture under pressure to the double-acting main cylinder, for more complete sweeping and filling.

-It is schematically represented in the drawing below.

“Two-stroke Helium engine schematic diagram”

-The two pistons are joined with a rigid rod and underneath it all it has the union with the normal rod.

-These engines are built in three main types: the rotary radial (also called "Alternate-rotary" by the manufacturer). A second type of Heliums are the fixed upright water-cooled ones. The third group are fixed radial engines.

“Running Helium rotary engine”

“Helium fixed radial”

-Below we show the cylinder details with two attached bodies. The one with the largest diameter is for the sweeping piston. The upper part, which is for the double acting piston, has a spark plug on each end, and ports in the central part.

“Cylinder and connecting rod system”

-Going over the production of double-effect Helium engines, we have:

-Alternative-rotary engines, air cooled.
AR-3, 45 CV and 3 cylinders.
BR-3, 60 CV and 3 cylinders.
BR-5, 100 CV and 5 cylinders.
BR-6, 120 CV and 6 cylinders.
BR-10, of 200 CV and 10 cylinders.

Fixed upright engines, water cooled
AO-3, 55 CV and 3 cylinders.
BO-3, 80 CV and 3 cylinders.
AO-6, of 120 CV and 6 cylinders in V.
BO-6, of 160 CV and 6 cylinders in V.

-Fixed radial engines, air cooled
AF-3, 45 CV and 3 cylinders.
AF-5, 75 CV and 5 cylinders.
BF-3, 60 CV and 3 cylinders.
BF-5, of 100 CV and 5 cylinders.

-Generally, all these powers were given at 1,200 rpm.

-Another proposed Helium engine for rotary engines of more than 100 CV with their great gyroscopic effect, was their "Degyroscopés" version.

-It was an engine divided into two groups, one rotating clockwise and the other anti-clockwise.

From Appendix 12: Helium was a builder of a wide range of aviation engines.

-We located a picture of a Helium engine, possibly a 6-cylinder BR-6 rotary radial.

-They were called -radial rotaries- as "Degyroscopés".

“Helium radial rotary”