An inventor from New York named A.G. Squadrani devised a system for aircraft engines to recover compression at altitude.

-The principle was based on a more complete filling of the cylinder.

-It is known that with altitude there comes a time when the throttle controls go to full (GAF) and the engine no longer gives any more power.

-To achieve this, the intake ducts are larger although restricted with an iris-type valve that automatically closes the passage when at the ground and by means of a barometric capsule the iris opens with the altitude.

-In addition, the opening time of the intake valve also varies, by means of conical cams that by driving the camshaft increase or decrease the opening time.

“Squadrani System” (popsci-PeT drawing)