How the Rogallo Flexible Wing Kite Works
A 1948 patent for a kite with a flexible, non-rigid wing that uses air pressure to maintain its shape during flight.
Original patent title: “Flexible kite”
A 1948 patent for a kite with a flexible, non-rigid wing that uses air pressure to maintain its shape during flight. Granted to Individual in 1951 with 23 forward citations, and it is now in the public domain.
Key facts
Coverage
What does this patent actually cover?
The patent describes a kite wing made of flexible material that lacks a rigid frame. Instead of using wooden struts to hold its shape, the wing relies on the pressure of the wind to inflate and maintain an airfoil shape while tethered. This design allows the kite to be lightweight, foldable, and capable of stable flight without heavy structural supports.
The gap
What does this patent NOT cover?
- Does not cover rigid-frame kites like traditional box or diamond designs.
- Does not cover motorized aircraft or powered flight vehicles.
- Does not cover wings made of rigid materials like metal or wood panels.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The inventors realized that a wing does not need a solid skeleton if the air pressure itself can act as the structural support, drastically reducing weight and complexity.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Modern hang gliders
Paragliders
Stunt kites
Parafoil parachutes
Why it matters
The bigger picture
This design became the foundation for modern hang gliders and paragliders. By proving that a flexible, fabric-based wing could provide stable lift, the Rogallos enabled the development of recreational foot-launched aviation.
Filed
November 23, 1948
Granted
March 20, 1951
Market context
Who's building on this
Companies in this space
The design was extensively researched by NASA in the 1960s for spacecraft recovery systems. Today, recreational aviation companies continue to refine the Rogallo wing geometry for hang gliding and paragliding equipment.
Market impact
The patent effectively birthed the sport of hang gliding. It shifted aviation design away from heavy, rigid structures toward lightweight, portable, and collapsible aerodynamic surfaces.
Claim 1 — Plain English
What this patent covers
The patent describes a kite wing made of flexible material that lacks a rigid frame. Instead of using wooden struts to hold its shape, the wing relies on the pressure of the wind to inflate and maintain an airfoil shape while tethered. This design allows the kite to be lightweight, foldable, and capable of stable flight without heavy structural supports.
The clever bit
The inventors realized that a wing does not need a solid skeleton if the air pressure itself can act as the structural support, drastically reducing weight and complexity.
What it does not cover
- Does not cover rigid-frame kites like traditional box or diamond designs.
- Does not cover motorized aircraft or powered flight vehicles.
- Does not cover wings made of rigid materials like metal or wood panels.
Patent Journey
From filing to expiry
PatentBrief Score
Impact Score
Early stage
Citation count
28/40
Moderately cited
Claim breadth
0/20
Narrow claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$20K – $63K
Midpoint $40K · expired or expiring · industry ×2.2
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Concepts involved
Citations
Patent lineage
Cite this patent
Sugden, R. G., & Melvin, R. F. (1951). How the Rogallo Flexible Wing Kite Works (U.S. Patent No. 2,546,078). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/2546078/rogallo-wing-hang-glider
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How the Rogallo Flexible Wing Kite Works cover?
A 1948 patent for a kite with a flexible, non-rigid wing that uses air pressure to maintain its shape during flight.
Who owns patent US 2546078?
Individual owns this patent, granted in 1951.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 2546078 cited by?
This patent has been cited by 23 later patents that build on its ideas.
What problem does this patent solve?
This design became the foundation for modern hang gliders and paragliders. By proving that a flexible, fabric-based wing could provide stable lift, the Rogallos enabled the development of recreational foot-launched aviation.
What does this patent NOT cover?
Does not cover rigid-frame kites like traditional box or diamond designs.
Same assignee
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