Dual rotor, rotary wing aircraft

Patent metadata

Field	Value
Publication number	US-10822076-B2
Application number	US-201515510553-A
Country	US
Kind code	B2
Filing date	Sep 30, 2015
Priority date	Oct 1, 2014
Publication date	Nov 3, 2020
Grant date	Nov 3, 2020

Abstract

A main rotor blade assembly for a rotary wing aircraft is provided including a main rotor blade root region, a main rotor blade inboard region arranged outboard of said main rotor blade root region, a main rotor blade main region arranged outboard of said main rotor blade inboard region, and a main rotor blade tip region arranged outboard of said main rotor blade main region. At least one of chord, twist, sweep, airfoil shape, and thickness/chord of the main rotor blade assembly has been optimized to achieve balanced high speed forward flight and hover relative to both efficiency and high thrust capability.

First claim

What is claimed is:

1. A coaxial counter-rotating main rotor blade assembly for a rotary wing aircraft having an upper rotor assembly and a lower rotor assembly rotatable about a common rotor axis, each of the upper rotor assembly and the lower rotor assembly including a plurality of rotor blades, each of the plurality of rotor blades, comprising:
a main rotor blade root region;
a main rotor blade inboard region arranged outboard of said main rotor blade root region;
a main rotor blade main region arranged outboard of said main rotor blade inboard region; and
a main rotor blade tip region arranged outboard of said main rotor blade main region, wherein a blade chord to blade radius ratio within the root region increases adjacent the inboard region from about 0.04 to about 0.08, a blade chord to blade radius ratio of the inboard region includes a substantially constant blade chord to blade radius ratio of about 0.08, a blade chord to blade radius ratio of the main region decreases from about 0.08 to about 0.05, and a blade chord to blade radius ratio in the tip region decreases from about 0.05 to about 0.03 in order to achieve balanced high speed forward flight and hover relative to both efficiency and high thrust capability and such optimization is for use both in the upper rotor assembly and in the lower rotor assembly.

2. The coaxial counter-rotating main rotor blade assembly according to claim 1 , wherein the main rotor blade root region extends from about 0% R to 20% R, the main rotor blade inboard region extends from about 20% R to 40% R, the main rotor blade main region extends from about 40% R to 90% R, and the main rotor blade tip region extends from about 90% R to 100% R.

3. The coaxial counter-rotating main rotor blade assembly according to claim 2 , wherein the main rotor blade tip region has a large negative twist angle extending between about −1° and −8°.

4. The coaxial counter-rotating main rotor blade assembly according to claim 2 , wherein the main rotor blade main region has a twist angle extending between about 3° and about −1°.

5. The coaxial counter-rotating main rotor blade assembly according to claim 2 , wherein the twist angle of a portion of the main rotor blade main region varies at a constant rate.

6. The coaxial counter-rotating main rotor blade assembly according to claim 2 , wherein the main rotor blade inboard region has a twist angle extending between about −6° and about 3°.

7. The coaxial counter-rotating main rotor blade assembly according to claim 2 , wherein the twist angle of the main rotor blade inboard region varies at a constant rate.

8. The coaxial counter-rotating main rotor blade assembly according to claim 2 , wherein the main rotor blade root region has a constant twist angle.

9. The coaxial counter-rotating main rotor blade assembly according to claim 2 , wherein the main rotor blade root region has a twist angle of about −6°.

10. The coaxial counter-rotating main rotor blade assembly according to claim 2 , wherein the main rotor blade tip region has an aft tip sweep of about 25°.

11. The coaxial counter-rotating main rotor blade assembly according to claim 2 , wherein a thickness to chord ratio of the rotor blade gradually decreases between the inboard region and the tip region from about .035 to about .01.

12. The coaxial counter-rotating main rotor blade assembly according to claim 1 , wherein at least one of sweep, chord, twist, and thickness to chord ratio of the rotor blade is defined in any of the following tables:

TABLE 1

Program
S-97

Configuration No./Designation
Raider ™

Date
Jan. 15, 2013

Hover Vtip (ft/s)
675

Lateral Lift Offset Limit
−0.28

Advancing Tip Mach Number Limit
0.90

Root cutout (r/R)
0.126

Pre-cone: Upper Rotor (+up)
3

Pre-cone: Lower Rotor (+up)
2

Total Rotor separation distance (d)
0.1347

Number of blades per rotor
4

Radius (ft)
17

Thrust-weighted solidity (per rotor)
0.07072

Thrust-weighted solidity (total)
0.14143

Thickness

r/R
AF
t/c (%)

0
CYL
1

0.1262
CYL
1

0.2
SCE433
0.33

0.32
SCE426
0.26

0.446
SC325222
0.22

0.57
SC36212
0.12

0.7
SC36210
0.1

0.8
SC36210
0.1

0.85
SC36210
0.1

0.9
SC36210
0.1

0.95
SC36210
0.1

1
SC36210
0.1

Assignees

• Sikorsky Aircraft Corp

Inventors

• Hunter David H
• Thomas Justin
• Beatty Robert D
• Tuozzo Nicholas Charles
• Egolf Thomas Alan
• Lorber Peter F
• Moffitt Robert C
• Westfall Shawn

Classifications

• B64C27/10 Primary

  arranged coaxially · CPC title

• G05D1/0858

  specially adapted for vertical take-off of aircraft · CPC title

• B64C27/12

  Rotor drives · CPC title

• B64C27/467

  Aerodynamic features · CPC title

• B64C2027/8236

  including pusher propellers · CPC title