You can freely build on How the Wright Brothers Invented Modern Airplane Control
This patent expired in 1923. Every claim — 0 independent, 0 dependent — is now unenforceable. Anyone can use, reproduce, manufacture, sell, or offer for sale this technology without a license.
Original assignee
Individual
Patent granted
1906
Expired
1923
Forward citations
19
What this patent covers
The patent describes a system for controlling a flying machine by warping the wings to maintain balance and steer. It utilizes a mechanism to twist the wing tips in opposite directions, creating a difference in lift that causes the aircraft to bank. This lateral control, combined with a vertical rudder, allowed the pilot to maintain stability against wind gusts and execute coordinated turns.
What is now free to use
All 0 claims of US 821393 are in the public domain. Specifically:
The 0 dependent claims add narrowing limitations and are also free.
What is NOT covered
Patent expiry frees this specific invention. Separately-patented improvements made after expiry may still be protected.
Does not cover jet propulsion or turbine engines.
Does not cover vertical takeoff and landing (VTOL) technology.
Does not cover fly-by-wire electronic flight control systems.
Does not cover pressurized cabins or high-altitude flight systems.
Who is building on this today
Every major aerospace manufacturer, including Boeing, Airbus, and Embraer, builds upon the fundamental principles of three-axis flight control established by this patent.
Products built on expired version of this technology
The Wright Flyer
Early 20th-century biplanes
Modern aileron-based flight control systems
How to cite this patent in your documentation
Individual. US Patent 821393. Flying-machine.. Granted 1906, expired 1923. Now in the public domain.
Note: This is a convenience citation. Consult a patent attorney for formal freedom-to-operate analysis.
PatentBrief is an educational resource and does not provide legal advice. Patent expiration information is derived from USPTO records and may not reflect continuation patents, divisional filings, or separately-patented improvements. For commercial use or production decisions, obtain a formal freedom-to-operate (FTO) opinion from a registered patent attorney.