# US 5,704,568 A · Airplane pirouette steering system

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 5,704,568 A
- Document ID: US5704568A
- Status: Granted
- Kind: A
- Application number: 08/395,337
- Filed: 1995-02-28
- Granted: 1998-01-06
- Earliest claimed: 1994-03-09
- Assignees: The Boeing Company
- Inventors: John Watts
- Web page: https://patentgrep.com/patent/US5704568A

## CPC

- B64C 25/50: Steerable undercarriages; Shimmy-damping
- B64C 2025/345: {Multi-wheel bogies having one or more steering axes}
- B64C: AEROPLANES; HELICOPTERS

## Abstract

An airplane steering system which permits 180 degree turns with minimum tire scrub. The system involves steering of both the nose landing gear and the front and rear wheels of both main landing gear each consisting of three inline wheels; thus, the center of turn is placed between the main gears and allows the airplane to make 180 "pirouette" turns.

## Claims

### Claim 1

In an aircraft having nose wheels and main gear wheels including a three axled truck beam having forward and aft axles steered relative to the truck beam, a method for aircraft pirouette turning comprising the steps of:
steering the aircraft nose wheels to a steering angle of about 90 degrees;
generating a turning moment around a turn center located substantially at the aircraft centerline between the aircraft's main gear wheels; and wherein said step of generating a turning moment around a turn center located substantially at the aircraft centerline between the aircraft's main gear wheels comprises using differential engine thrust between left and right engines.

### Claim 2 (depends on 1)

The invention according to claim 1 wherein generating a turning moment around a turn center located substantially at the aircraft centerline between the aircraft's main gear wheels comprises turning at least one of the axles each on the left and right main landing gears for minimizing main landing gear wheel scrub levels during a pirouette turn.

### Claim 3 (depends on 1)

The invention according to claim 1 wherein generating a turning moment around a turn center located substantially at the aircraft centerline between the aircraft's main gear wheels comprises using forward and rearward powered main landing gear wheels on opposite sides of said aircraft.

### Claim 4 (depends on 1)

The invention according to claim 1 wherein generating a turning moment around a turn center located substantially at the aircraft centerline between the aircraft's main gear wheels comprises using powered nose wheels.