Helicopter control relies on countering the torque of the main rotor. The are many ways to do this, but the most common is the use of a tail rotor.
Tailrotors function not only as an anti-torque device, but also as a yaw control device. Many tailrotors use a flapping hinge called a delta-3 hinge to introduce pitch flap coupling.
This video will also cover design specific details of the UH-60 Blackhawk tailrotor.
In helicopters, controlling torque produced by the main rotor is necessary for controlled flight. While there are various methods to achieve this, the most common solution is the tail rotor.
A tail rotor not only counters main rotor torque but also provides yaw control, allowing for direction changes while hovering. Many tail rotors, including the one on the UH-60 Blackhawk, feature a unique flapping hinge known as a delta-3 hinge. This hinge introduces pitch-flap coupling, which constrains maximum blade flapping.
In this video, we'll cover the principles of tail rotor function, explore the design intricacies of the UH-60 Blackhawk's tail rotor, and examine how these systems work together to maintain stability and control.
References
- Black Hawk: The Story of a World Class Helicopter, Leoni, R.D., 2007, American Institute of Aeronautics and Astronautics
- US Patent; Rotor System With Pitch Flap Coupling, Schmalling, D.N, US 2008/0112808
- US Patent; Optimized Composite Flexbeam for Helicopter Rotors, Schmalling, D. N, US 1998/5738494
- US Patent; In-Plane and Out-of-Plane Flapping Prop-Rotor Frequency Decoupling, Gaffey, T.M, Wernicke, K. G, US 1974/28045
- US Patent; Circulation Control Slots in Helicopter Yaw Control System, VanHorn, J., US 1990/4948068
- Robinson Tail Rotor Design and History; Tucker, T; 2020 timtuckershelicopterworld.com (
https://www.timtuckershelicopterworld.com/post/robinson-tail-rotor-design-and-history)Image Credits
- H-19 Rotor Hub
https://commons.wikimedia.org/wiki/File:Milestones-h19-070919-03-16.jpg - Alan Radecki Akradecki, CC BY-SA 3.0
https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons
- Public Domain images are credited within the video
00:00 Intro
00:37 Anti-torque to Counter Main Rotor Rotation
01:14 Methods of Anti-torque
03:38 Anti-torque Control
04:37 Yaw and Heading Control
05:05 Dissymmetry of Lift
06:14 Pitch Flap Coupling
06:45 Delta-3 Flapping
09:07 Delta-3 on Main Rotor Blades
09:57 Historical Perspective
10:26 Tailrotor Drive System
11:45 Right or Left Side Tailrotor
13:44 The Blackhawk Right Side Tailrotor
15:40 Flexbeam Tailrotor
17:03 Canted Tailrotor