# US 2014/0191088 A1 · Aircraft With Integrated Lift And Propulsion System

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- Number: US 2014/0191088 A1
- Document ID: US20140191088A1
- Status: Published application
- Kind: A1
- Application number: 14/010,382
- Filed: 2013-08-26
- Published: 2014-07-10
- Earliest claimed: 2005-08-15
- Inventors: Abe Karem
- Web page: https://patentgrep.com/patent/US20140191088A1

## CPC

- B64C 29/0033: {the propellers being tiltable relative to the fuselage}
- B64C 3/10: Shape of wings
- B64C 27/28: with forward-propulsion propellers pivotable to act as lifting rotors
- B64C 27/467: Aerodynamic features
- B64C 3/385: {Variable incidence wings}
- Y02T 50/10: Drag reduction
- B64C: AEROPLANES; HELICOPTERS
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A vertical take off and landing (VTOL) aircraft is designed to be so efficient that it can be commercially competitive with runway dependent aircraft operating in a range of 100 to 1000 miles. Improvements include a high efficiency tilting rotor and wing design that enable both vertical takeoff and efficient high speed cruising, a high aspect ratio wing, and a variable speed propulsion system that is efficient in both hover and cruise flight. Preferred aircraft use thin inboard and outboard wings, thin rotor blades, and use efficient lightweight design to achieve unusually low empty weight fraction. Inventive methods include utilization of advanced design and analysis techniques, which allow for accurate prediction of an aircraft's physical behavior.

## Claims

### Claim 1

A flight operational tilt rotor aircraft, comprising:
a fuselage;
a rotor having a diameter of at least 20 feet, with at least first and second radially extending rotor blades;
a propulsion system that rotates the rotor at variable speed during forward flight to at least as low as 70-75% of maximum rpm in hover;
an inboard wing that couples the rotor to the fuselage; and
a tilting outboard wing coupled to the inboard wing.

### Claim 2 (depends on 1)

The aircraft of claim 1, wherein the fuselage has a fineness ratio of at least 4.

### Claim 3 (depends on 1)

The aircraft of claim 1, wherein the fuselage has a cross sectional area between 3%-12% of a planform area of the inboard wing.

### Claim 4 (depends on 1)

The aircraft of claim 1, wherein the rotor has a diameter of at least 40 feet.

### Claim 5 (depends on 1)

The aircraft of claim 1, wherein the rotor has a disc loading of 23-30 pounds per square foot at a maximum hover weight.

### Claim 6 (depends on 1)

The aircraft of claim 1, wherein the rotor has a disc loading of 30-40 pounds per square foot at a maximum hover weight.

### Claim 7 (depends on 1)

The aircraft of claim 1, wherein the rotor has a disc loading of 40-50 pounds per square foot at a maximum hover weight.

### Claim 8 (depends on 1)

The aircraft of claim 1, wherein the rotor has a disc loading of 50-60 pounds per square foot at a maximum hover weight.

### Claim 9 (depends on 1)

The aircraft of claim 1, wherein the rotor has a disc loading of 60-70 pounds per square foot at a maximum hover weight.

### Claim 10 (depends on 1)

The aircraft of claim 1, wherein the rotor is configured to provide a cruise propulsion efficiency of at least 0.83.

### Claim 11 (depends on 1)

The aircraft of claim 1, wherein the rotor is configured to propel the aircraft in forward cruise speed of at least Mach 0.55.

### Claim 12 (depends on 1)

The aircraft of claim 1, wherein the propulsion system rotates the rotor during forward flight to at least as low as 50% to 60% of maximum rpm in hover.

### Claim 13 (depends on 1)

The aircraft of claim 1, wherein the propulsion system rotates the rotor during forward flight to as low as 30% to 50% of maximum rpm in hover.

### Claim 14 (depends on 1)

The aircraft of claim 1, where the inboard wing has an aspect ratio of at least 5.

### Claim 15 (depends on 1)

The aircraft of claim 1, where the inboard wing has an aspect ratio of at least 10.

### Claim 16 (depends on 1)

The aircraft of claim 1, where the inboard wing, and has a wing loading of at least 30 pounds per square foot at maximum take-off weight.