Igor Sikorsky's Early Design for a Vertical Takeoff Aircraft
A 1935 patent by aviation pioneer Igor Sikorsky detailing a mechanical configuration for an aircraft capable of direct vertical lift.
Original patent title: “Direct lift aircraft”
A 1935 patent by aviation pioneer Igor Sikorsky detailing a mechanical configuration for an aircraft capable of direct vertical lift. Granted to Sikorsky Aircraft Corp in 1935 with 16 forward citations, and it is now in the public domain.
Key facts
Coverage
What does this patent actually cover?
The patent describes a structural arrangement for an aircraft designed to achieve vertical flight through direct lift mechanisms. It focuses on the mechanical integration of rotors or lifting surfaces that allow an aircraft to ascend without a traditional horizontal runway takeoff. By positioning the lifting components to provide upward thrust directly, the design enables the craft to hover or climb vertically.
The gap
What does this patent NOT cover?
- Does not cover modern fly-by-wire electronic flight control systems.
- Does not cover turbine-powered propulsion systems, as it predates their aviation use.
- Does not cover multi-rotor drone configurations common in modern consumer electronics.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The innovation lies in the specific mechanical linkage that allowed for stable vertical ascent, solving the critical problem of balancing lift and torque in a single-rotor or early multi-rotor setup.
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
Early Sikorsky VS-300 prototypes
Piston-engine utility helicopters
Why it matters
The bigger picture
This patent represents a foundational step in the development of the modern helicopter. Igor Sikorsky's work transitioned vertical flight from theoretical experimentation to a practical engineering discipline, eventually leading to the mass production of helicopters for military and civilian rescue operations.
Filed
June 27, 1931
Granted
March 19, 1935
Market context
Who's building on this
Companies in this space
Sikorsky Aircraft, now a subsidiary of Lockheed Martin, continues to build on these foundational vertical lift concepts. Modern aerospace companies like Bell Flight and Airbus Helicopters also iterate on the core physics of rotor-driven lift established in this era.
Market impact
This patent helped establish the technical feasibility of the helicopter industry. It provided a legal and engineering framework that allowed Sikorsky to secure funding and development resources, effectively launching the vertical flight sector that remains essential for search and rescue and military logistics today.
Claim 1 — Plain English
What this patent covers
The patent describes a structural arrangement for an aircraft designed to achieve vertical flight through direct lift mechanisms. It focuses on the mechanical integration of rotors or lifting surfaces that allow an aircraft to ascend without a traditional horizontal runway takeoff. By positioning the lifting components to provide upward thrust directly, the design enables the craft to hover or climb vertically.
The clever bit
The innovation lies in the specific mechanical linkage that allowed for stable vertical ascent, solving the critical problem of balancing lift and torque in a single-rotor or early multi-rotor setup.
What it does not cover
- Does not cover modern fly-by-wire electronic flight control systems.
- Does not cover turbine-powered propulsion systems, as it predates their aviation use.
- Does not cover multi-rotor drone configurations common in modern consumer electronics.
Patent Journey
From filing to expiry
PatentBrief Score
Impact Score
Early stage
Citation count
25/40
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
$8K – $26K
Midpoint $16K · expired or expiring · industry ×0.9
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
Sikorsky, I. I. (1935). Igor Sikorsky's Early Design for a Vertical Takeoff Aircraft (U.S. Patent No. 1,994,488). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/1994488/helicopter-sikorsky
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
Embed
Add this patent to your site
Drop this plain-English patent card into any blog post or article — free, no signup. It always links back to the full breakdown here.
<div data-patentlens-widget data-patent-number="US1994488"></div> <script src="https://patentbrief.org/embed.js" async></script>
Stay in the loop
Get a weekly digest of new patents.
One email per week. No spam. Unsubscribe anytime.
Keep exploring
Related patents you should know
US 4683195 · 1987
How to Make Billions of Copies of a DNA Segment
This patent describes the Polymerase Chain Reaction (PCR), a method to rapidly create many copies of a specific piece of DNA or RNA, enabling its detection and analysis.
Cetus Corp
US 8697359 · 2014
How to Edit Genes in Human Cells Using an Engineered CRISPR System
This patent describes an engineered CRISPR-Cas9 system for precisely cutting DNA in eukaryotic cells to change how genes work, opening the door for gene editing in complex organisms.
Massachusetts Institute of Technology
US 7657849 · 2010
How the iPhone's Slide-to-Unlock Gesture Works
Apple's 2010 patent describes unlocking a device by dragging a specific graphical image across the touchscreen along a predefined path, a gesture that became iconic with the original iPhone.
Apple Inc
US 4733665 · 1988
How Doctors Implant a Permanent Stent Using a Balloon
This patent describes the method for placing a permanent, expandable wire mesh tube inside a blood vessel or other body tube using a balloon-tipped catheter to widen it and keep it open.
Expandable Grafts Partnership
US 4405829 · 1983
How RSA Public-Key Encryption Keeps Digital Messages Secret
This patent describes the foundational RSA algorithm, a method for securely sending messages where anyone can encrypt a message using a public key, but only the intended recipient can decrypt it using a secret private key.
Massachusetts Institute of Technology
US 4575330 · 1986
How 3D Printers Build Objects Layer by Layer from Liquid
This patent describes the foundational method for 3D printing, where a machine builds a three-dimensional object layer by layer by hardening a liquid material with light or other energy.
UVP Inc
Semantically similar
You might also find these interesting
New to patents?
Common Questions
Frequently Asked Questions
What does Igor Sikorsky's Early Design for a Vertical Takeoff Aircraft cover?
A 1935 patent by aviation pioneer Igor Sikorsky detailing a mechanical configuration for an aircraft capable of direct vertical lift.
Who owns patent US 1994488?
Sikorsky Aircraft Corp owns this patent, granted in 1935.
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 1994488 cited by?
This patent has been cited by 16 later patents that build on its ideas.
What problem does this patent solve?
This patent represents a foundational step in the development of the modern helicopter. Igor Sikorsky's work transitioned vertical flight from theoretical experimentation to a practical engineering discipline, eventually leading to the mass production of helicopters for military and civilian rescue operations.
What does this patent NOT cover?
Does not cover modern fly-by-wire electronic flight control systems.
Patent monitoring