# 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.

- **Patent:** US 1994488
- **Original title:** Direct lift aircraft
- **Owner:** Sikorsky Aircraft Corp
- **Granted:** 1935
- **Status:** Public domain (expired)
- **Times cited:** 16
- **Field:** aerospace, mechanical

## What it does

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.

## 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.

## 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.

## Real-world examples

1. Early Sikorsky VS-300 prototypes
2. Piston-engine utility helicopters

## Why it matters

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.

## 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.

**Full plain-English explainer:** https://patentbrief.org/patent/us/1994488/helicopter-sikorsky

**Original patent:** https://patents.google.com/patent/US1994488

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_Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._


## Related patents

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- [Frank Whittle's Early Jet Engine Design](https://patentbrief.org/patent/us/2168726/jet-engine-whittle) — Frank Whittle's 1937 patent for an aircraft propulsion system using a gas turbine, which laid the foundation for modern jet engines.
- [Robert Goddard's Early Design for Liquid-Fueled Rocket Engines](https://patentbrief.org/patent/us/1102653/liquid-fuel-rocket-goddard) — A foundational 1914 patent by Robert Goddard detailing the basic mechanical structure of a rocket engine using liquid fuel.
- [How Early Hard Disk Drives Accessed Data Quickly](https://patentbrief.org/patent/us/3503060/hard-disk-drive) — A 1970 patent detailing a mechanical system for moving read-write heads across magnetic disks to retrieve stored information rapidly.
- [Leamon Souder's 1903 Design for a Spiral Escalator](https://patentbrief.org/patent/us/723325/escalator-moving-stairway) — A 1903 patent for a mechanical staircase that moves in a circular, spiraling path to transport people between floors.