Afghanistan Conditions Lead to Resurgence in Active Rotor Blade Research

Boeing SMART Rotor


H-60 Rotor with Individual Blade Control (IBC)


DARPA Concept: Potential Settings for Active Rotor

One of the differences between rotor blades and modern aircraft wings is the relative lack of sophistication of the rotor blades. While wings have had flaps and/or slats for years, and have actively changed the shape of the wing with the benefit of fly-by-wire controls since the 1970s, the F-16 being a prime example, rotor blades have remained a single fixed airfoil with no leading or trailing edge devices.

The extreme conditions in Afghanistan, where it can be hot, and it's always high, have led to new research into leading and trailing edge devices for helicopter rotors.

Sikorsky is testing a control system with individual blade control, a departure from the current swash plate setup used in helicopters (middle picture) in addition to testing a system with actively blade flaps, and Boeing is testing a rotor with piezoelectrically driven flaps. (top picture)

Additionally, Sikorsky is looking at some more involved, and potentially fieldable concepts:

As part of the 30-month active rotor program with AATD, Sikorsky will also study active blade slats, adaptive flight controls and a dual-frequency rotor head-mounted vibration suppression system. The study will produce the conceptual design for an H-60 [Blackhawk & Seahawk] size active rotor.

DARPA is in on this too, with its Mission Adaptive Rotor program. (the mission adaptive wing program of the early 1970s led to much of what we have now on fixed wing aircraft).

They anticipate increases in payload and range of 30-40%, reducing noise by 50%, and reducing vibration by 90%.