Ever watch a hummingbird suspend its body in mid-air with the rapid flapping of its tiny wings? AeroVironment Inc. has certainly seen it. In fact, the company was successful this month in replicating those movements.

AeroVironment has a full portfolio of unmanned aircraft systems. Its announcement of a hummingbird-like aircraft was a significant step forward for that portfolio.

According to the company’s February announcement, the project feat was “successfully executed the control precision hovering and fast-forward flight of a two-wing, flapping wing aircraft that carries its own energy source and uses only the flapping wings for propulsion and control.”

The milestone was part of the Phase II contract awarded by the Defense Advanced Research Projects Agency (DARPA) to AV to design and build a flying prototype “hummingbird-like” aircraft for the Nano Air Vehicle (NAV) program.

The final concept demonstrator is called the Nano Hummingbird. It is capable of climbing and descending vertically, flying sideways left and right, flying forward and backward, and rotating clockwise and counter-clockwise. It can maneuver in this way under remote control and while carrying a video camera payload.

During the demonstration, the Nano Hummingbird flew in and out of a building through a normal-size doorway.

The success of the Nano Hummingbird was “dependent on the intense combination of creative, scientific, and artistic problem-solving skills from the many AV team members, aided by a philosophy of continuous learning,” stated AeroVironment in its announcement.

The hand-made prototype aircraft has a wingspan of 16 centimeters (6.5 inches) tip-to-tip and has a total flying weight of 19 grams (2/3 ounce), which is less than the weight of a common AA battery. That weight includes all the systems required for flight: batteries, motors, communications systems, and video camera.
The aircraft can be fitted with a removable body fairing, which is shaped to have the appearance of a real hummingbird. The aircraft is larger and heavier than an average hummingbird, but is smaller and lighter than the largest hummingbird currently found in nature.

The technical goals for the Phase II effort were set out by DARPA as flight test milestones for the aircraft to achieve by the end of the contract effort. The Nano Hummingbird met all, and exceeded many, of these milestones:

• Demonstrate precision hover flight within a virtual two-meter diameter sphere for one minute.
• Demonstrate hover stability in a wind gust flight.
• Demonstrate a continuous hover endurance of eight minutes with no external power source.
• Fly and demonstrate controlled, transition flight from hover to 11 miles per hour fast forward flight and back to hover flight.
• Demonstrate flying from outdoors to indoors and back outdoors through a normal-sized doorway.
• Demonstrate flying indoors ‘heads-down,’ where the pilot operates the aircraft only looking at the live video image stream from the aircraft, without looking at or hearing the aircraft directly.
• Fly the aircraft in hover and fast forward flight with bird-shaped body and bird-shaped wings.

“The success of the NAV program paves the way for a new generation of aircraft with the agility and appearance of small birds,” says DARPA NAV program manager Dr. Todd Hylton.