IP Library Granted Patent US 7,887,298
Granted Patent B2
US 7,887,298 · App. 11/165,655 · Granted Feb 15, 2011

Vertically staggered helicopter rotor blade assembly

Assignee: Northrop Grumman Systems Corporation
View Patent ↗
Loading inventors, assignments & file history…
Monitor This Case
Get email alerts when status or documents change.
Order Certified Copies
Most orders are placed with the USPTO same day — all within 24 business hours.
Order via The Patent Place →
Pre-filled with this patent's details
Quick Facts
Patent No.
US 7,887,298
App. No.
11/165,655
Granted
Feb 15, 2011
Kind
B2
Abstract

A helicopter rotor assembly with vertically staggered blades is disclosed. Each blade travels in a rotational path which does not cross the rotational paths of the other blades. This arrangement reduces noise because each blade travels in a path which avoids turbulent or disturbed air from the preceding blades. In one embodiment, the blades are arranged from the lowermost blade to the uppermost blade such that each blade following the lowermost blade will be above the blade in front of it. Since each blade pushes air down to create lift, this vertically staggered arrangement allows the blades to travel through less disturbed air.

Claims (7)

1. A helicopter rotor assembly comprising at least three blades located at vertically staggered positions from a lowermost blade to an uppermost blade and at different rotational positions with respect to each other, wherein each blade has a rotational path and pushes air down as it travels in its rotational path to create lift, the rotational path of each blade is vertically separated from and does not cross the rotational paths of the other blades, and each blade following the lowermost blade travels in a rotational path located vertically above and rotationally behind the blade immediately below it.

2. The helicopter rotor assembly of claim 1 , wherein each blade extends in a substantially straight direction from a rotor shaft to which the blades are attached.

3. The helicopter rotor assembly of claim 2 , wherein each blade extends in a substantially horizontal direction from the rotor shaft.

4. The helicopter rotor assembly of claim 1 , wherein each blade travels in a rotational path defining a substantially flat plane.

5. The helicopter rotor assembly of claim 4 , wherein each plane is substantially horizontal.

6. The helicopter rotor assembly of claim 1 , wherein the assembly comprises four of the blades.

7. The helicopter rotor assembly of claim 1 , wherein the blades are located at substantially equal angular positions with respect to each other.

Assignments (3)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jan 7, 2011
From: NORTHROP GRUMMAN CORPORATION
To: NORTHROP GRUMMAN SYSTEMS CORPORATION
Reel/Frame 025597/0505 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Sep 27, 2010
From: NORTHROP GRUMMAN CORPORATION
To: NORTHROP GRUMMAN SYSTEMS CORPORATION
Reel/Frame 025044/0336 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jun 24, 2005
From: ARATA, ALLEN A.
To: NORTHROP GRUMMAN CORPORATION
Reel/Frame 016690/0379 →
Continuity (1)
Related Publication 20060292009A1 · Dec 28, 2006