Ball Lightning(44)

Lin Yun described the test procedure for them: “First, ascend to five thousand meters, and then bring the two craft as close together as is safe. When you’re at that distance, ignite the arc, then gradually separate the two craft and hover just under the arc’s maximum range. Then fly forward at the speed given by the ground commander. Pay attention to arc stability and hover if you need to—you’ve done that before. One more thing to watch out for: if the arc goes out, then disengage as fast as possible and turn off the generator. Don’t try to reestablish the arc, since if it’s ignited at long range, it may strike the aircraft! Make sure you remember that. Don’t die a martyr.”

According to the plan, the helicopters would fly with the wind to minimize the relative airspeed. Then they would ignite the arc and fly for a while until it went out, at which point they would come back and repeat the process.

The test helicopters quickly ascended to the predetermined altitude. At this point we had to use binoculars to see them. They flew with the wind and drew closer to each other until it looked from the ground like their rotors were practically touching. Then a bright electric arc appeared between the two craft, projecting a dim yet crisp popping sound down to earth. The helicopters slowly separated, and the arc stretched out, its initial straight line becoming more turbulent as the distance increased. At maximum separation, it seemed like a piece of light gauze dancing on the wind, liable to slip its bindings and fly off into the sky. The sun was still below the horizon, and the bright blue-purple electric arc looked unreal against the dark blue of the sky between the helicopters’ black silhouettes, like the projection of scratched film on a cinema screen.

I had a sudden chill, my stomach tightened, and I began shivering uncontrollably. I set down the binoculars. With the naked eye, all I could see was a blue dot high in the sky, like a nearby star.

When I picked them up again, the helicopters were flying forward at maximum separation, taking with them that dancing, hundred-meter electric arc. Their speed was so low that it was only by comparing them to the thin high clouds, lit by the sun below the horizon, that you could tell they were moving. As they flew east, their sunlit bodies turned into two orange dots, and the arc dimmed slightly.

I exhaled, but then heard shouts from the binocular watchers beside me. I grabbed up my own pair to catch the scene: on the receptor side, the arc had forked. Its main branch still contacted the electrode, but a smaller branch moved erratically along the helicopter’s tail like it was a thin hand searching for something. It lasted only three or four seconds, and then the arc went out altogether.

The situation didn’t look scary and seemed unlikely to have any disastrous consequence on the helicopter. But I was wrong. The instant the arc vanished, I saw a bright light in the tail rotor. It vanished immediately, but then smoke appeared at that spot, and shortly after, the helicopter began to rotate, faster and faster. Later I learned that the lightning had struck a control line for the tail rotor, causing it to stop. Since that rotor was used to balance the rotational torque generated by the main rotor, once it lost power, the helicopter began to rotate in the opposite direction from the main rotor. Through the binoculars I saw the rotation accelerate and the helicopter gradually lose lift, then start a shaky fall.

“Bail!” Colonel Xu shouted into the radio.

But just seconds later, it looked like the pilot had restarted the tail rotor. The rotation of the fuselage slowed, as did the speed of descent, until it once again hovered in the air—but only for a split second. Then, like a clockwork toy, it started to turn again and plummet.

“Bail!” Colonel Xu shouted again.

After a short fall, the helicopter again stopped rotating and slowed to a hover. The next instant it began falling again...?and the cycle repeated. Now it was below the safe altitude for parachuting. We could only pray that it reached the ground when it was near a hover state.

When it landed off to the east, its speed had slowed significantly, but it was still far faster than a normal landing. I looked fearfully in that direction and waited numbly. Luckily, no smoke came from that stand of trees.

When we drove up to the crash spot, the other test helicopter had already landed nearby. The site was in an orchard. The helicopter was tilted, crushing a few fruit trees beneath it, and the tops of several other stocky trees around it had been severed by the blades. The cabin glass had shattered, but apart from that, the fuselage did not appear to be seriously damaged. The lieutenant was leaning against a tree pressing a bleeding arm, impatiently trying to push off the nurse and stretcher carrier, but when he saw Lin Yun he used his unharmed hand to give her a thumbs-up.

“Major, your lightning weapon took out a plane!”

“Why didn’t you bail out?” Colonel Xu, who had just arrived, asked in exasperation.

“Colonel, we army aviators have our own rules for when to bail out.”

In the car back to the base, I couldn’t hold back one nagging question, and said to Lin Yun, “You were the designated ground commander for this test. But it was Colonel Xu who gave the order to parachute.”

“It was very possible that Lieutenant Liu would be able to rescue the helicopter,” Lin Yun said evenly.

“There was only a fifty percent likelihood of that. What if he couldn’t save it?”

“Then the experiment would be suspended for quite some time, and the project might even be canceled.”