Two centuries and a half afterwards inventors began to multiply.

In 1742 the Marquis de Bacqueville designed a system of wings, tried it over the Seine, and fell and broke his arm.

In 1768 Paucton conceived the idea of an apparatus with two screws, suspensive and propulsive.

In 1781 Meerwein, the architect of the Prince of Baden, built an orthopteric machine, and protested against the tendency of the aerostats which had just been invented.

In 1784 Launoy and Bienvenu had maneuvered a helicopter worked by springs.