Towers of the Wind
Wind was driving hard a few feet from Arun's face. For now the protective glass skin of the building separated him from that intense flow, but he knew in a few minutes he would be outside in the grip of that invisible fist.
“Today we have a tail!” Supervisor Cahil said from behind Arun. “Do you see it?”
Arun shook his head no.
“They don't teach you these things in school,” the Supervisor moved next to Arun and pointed toward the point where the Hudson met the East River to the south. “But you need to learn them. As the wind is ducted through the towers, it picks up heat and water vapor. When it hits the cooler air over the water, the water vapor condenses, and you can see it tailing off the island.”
“So it creates a fog?” Arun asked.
“More of a thin cloud. The ducting formed by the buildings and skyways discharges at over a hundred feet above the water, so most of the time you wouldn’t be able to see it from nearby. But from here, with the sunlight reflecting off the water vapor, we can see it clearly.”
“You said today we have a tail— not every day?”
“No. It depends on the weather conditions and what direction the wind is blowing. And that’s why you always check before going skinside on a building. Now, what do you see?” Set into the roughened skin of the Supervisor were two sharp blue eyes which were now probing Arun to see if he understood what he was seeing.”
Arun inhaled and concentrated on all he had learned in his City Operations classes. “The wind must be coming mostly from the north right now.”
“Correct—and what does that mean?”
“It blows harder?”
“No,” a small scowl crossed the Supervisor's face. “Think about it.”
“I'm not sure I understand.”
“Think on a larger scale. What season is it?” Cahil prompted.
“It's autumn...autumn...” Arun tried to figure out how autumn would affect his first venture skinside. “Coming from the north... it will be colder air?”
“Most likely. And drier,” the Supervisor nodded. “Check your gear. Do you have the right gear?”
Arun looked at his envirosuit. It all seemed to be in place and he had checked for tears or scuffs before putting it on. Perhaps it didn't fit as well as the Supervisor's suit, but student suits tended not to. He felt his hands, checking the tactile response of his protective gloves. They seemed OK. His goggles, though also student-issue, were clean and every filter still worked. The tool kits were standard-issue with all the required safety lines.
“I think so,” Arun replied. “But I'm not sure.”
“On a day like today,” Supervisor Cahil said, “you will want to add a medium headsock. It will help keep your body heat in and keep your skin from becoming windburned. We keep a supply up here.” He handed a small piece of dense fabric to Arun. “Because you never really know what conditions will be like.” He demonstrated how to tuck the headsock into the envirosuit to get the best fit.
“Do we even need the full helmets?” Arun asked as he adjusted the headsock.
“Sometimes, but I'd never take a student out for their first skinside on a day like that.”
“That's good,” Arun was relieved.
“Let's do a final review,” Cahil said. “Our task is...?”
“Repair a bad actuator on an airfoil,” Arun replied.
“And the plan to do that?”
“From the skin access, we line horizontally to above the airfoil, then drop to it.” Arun ran through the plan in his mind step by step.
“And then?”
“We check the actuator.”
Cahil shook his head. “Before that?”
“Oh! We lock the airfoil down!” Arun realized.
“Always. With a bad actuator that may be difficult, so follow my instructions. Sometimes the wind will help, sometimes we have to fight it. It takes experience to know the safest way to work.” Cahil looked directly at Arun, reading the young man's face.
“I will follow your lead.”
Cahil opened the interior door of the skin access portal and stepped into the small chamber. Arun followed and closed the door as he had been trained. Now the two stood side by side, facing out of the building. The both reached up and took a safety line from modules on the rail above. Connecting the lines to a reinforced track around the waist on their envirosuits, they were almost ready to leave the comfortable safety of the building. Two indicators lit up green, and they keyed in their codes on the small pad built into the wrist of their suits. Once both had entered their codes, the lights began to flash yellow and a low warning tone sounded.
With just the smallest of vibrations, the window panel before them began to slide out and down. Arun was hit with a blast of cold air and winced as the intense sunlight hit him full in the face. It took only seconds for the filters in the goggles to adjust, and a moment longer for Arun's eyes to adjust. Below them the facade of the building curved gently away from their perch. Arun know that above him it curved up into a spire, but he did not look at the moment.
Supervisor Cahil reached up to the rail and pushed his line module out until it clicked. “You doing OK, Arun?” he asked.
“It's different than the simulator. Just taking a moment to adjust,” Arun said.
“Take your time. When you are ready, push your line out the way I did. At this point we are on wireless comms to each other, but hard comms to the building. If our wireless fails, the hard comm backs it up. Understand?”
“Yes, I'm ready.” Arun reached up and pushed the line module out until he heard the click. A small indicator in his goggles turned green.
“You have practiced stepping out in the simulators, but this will be different,” Cahil coached Arun. “Trust your line and your gear. I will be behind you to steady you if needed.”
Arun stepped forward onto the small lip formed by the top edge of the window panel as it slid out of the way. Now he could really feel the wind tugging at his suit. In one motion, he swung his left leg out and pivoted on his right heel until his left foot touched the skin of the building and he was standing almost perpendicular to the surface, his weight supported by the line. He flexed his knees slightly to test his weight.
“Feel good?” Cahil's voice sounded in the comm.
“Yes.”
“Take a step, then, and let me out.”
Arun took a step sideways to make room, and the line module slid effortlessly along the track above him. Cahil stepped out smoothly and nodded to Arun. Together they started to walk along the face of the building, held to the curving facade by their lines but buffeted by the chill wind.
As they moved along the facade, a tone in their comms ticked off their progress. Several times the wind caused Arun to slip, even with the specially designed boots he was wearing. Cahil helped him regain his footing and they kept going. As they neared their down point, the comms sounded a double tone, and then a triple. Arun heard it become constant and then paused. Turning his head to look down, he could see the large airfoil that was their destination. Other airfoils were scattered on the facade, controlling the flow of the wind around the building and helping ventilate it.
After explaining to Arun how to keep their lines from crossing and becoming tangled, Cahil led their descent to the airfoil. Just above the range of motion etched into the facade over the years, Cahil stopped, with Arun overhead.
It was clear that the airfoil was not positioned correctly. Even in the north wind buffeting the island of Manhattan, the other airfoils on the building remained steady, moving smoothly as the wind changed, but this one twisted and shook with each gust. Arun struggled to keep his footing, realizing why they had moved horizontally first. Their lines, when kept short up near the track, provided a very secure feel and helped keep their footing sound. Now that the lines were extended, a slip could mean flopping around in the wind like a tattered flag. Though the curve of the building kept the lines from catching too much wind, Arun could still feel his line vibrating with the force of the moving air. He knew if he lost his footing entirely the module would automatically winch him safely up, but he didn't want to have that happen, especially his first time skinside.
“Take this line.” Cahil handed Arun a coil of rope. “And pay it out to me as I go down to the airfoil. Move a few meters to your left to avoid fouling our lines.”
Arun secured the cleat color coded as the top end of the line to a reinforced spot on his envirosuit, keeping just a slight tension on it as Cahil walked down the facade to the twisted airfoil. Once he was on the airfoil itself, he carefully slid to a place where there was a yellow circle and clipped the line into it. Tapping his wristpad, Cahil walked back up the building to stand near Arun.
“With the damaged actuator, the airfoil will need help to move to the locked position. Do you feel up to hauling it?” Cahil asked.
“Yes,” Arun replied uncertainly.
“Then rotate fully face down, slowly. Once you are steady, I will release the pitch lock and you will need to pull the airfoil up toward the lock position. The actuator is stuck in its extended position, causing the airfoil to catch more wind than it should so the pitch motors will have a hard time starting without help. It will be hardest at first and get easier.”
Arun did as Cahil said, taking up slack on the line. Cahil touched his wrist pad and suddenly Arun felt the motion of the airfoil in the line. Arun hauled as hard as he could, feeling the airfoil move in steps as the pitch motors tripped and reset under the unusual load. At first it seemed he needed all his strength to help the airfoil move, but as it started to move, the vibrations in the line became more tiring than the weight.
As the airfoil came close to level it became easier to pull and Arun was relieved to feel the safety locks click into place. With the airfoil secured the two walked down to the now level surface of the airfoil and Cahil showed Arun how to clip into the edge and safely crawl along the surface of the vibrating structure as the wind whipped around them.
Finally they reached the access panel for the actuator. Opening the panel, they immediately saw that the actuator rod was bent, keeping it from retracting.
“First step is to retract that flap,” Cahl said. “So the foil becomes more stable.” He pulled a device that looked like the actuator out of a pocket in the leg of his envirosuit. “See the second bracket in there? That's for the manual adjuster. Do you see how it goes in?”
“Yes, we did this in class,” Arun answered.
“Go ahead then.”
Arun extended the adjuster to match the position of the brackets, locked it into place and tightened it enough to take tension off the actuator. Together they disconnected the actuator and removed it, using safety lines just in case something slipped. It was a long way down to the streets of Manhattan, and anyone hit by an actuator falling from that height would not appreciate it.
“Now the hard work.” Cahil safetied a ratchet and passed it to Arun. “Just like moving the foil, it will get easier as you go.”
Arun's muscles disagreed with the idea that moving the foil had gotten easier, but he remained quiet and began to draw the flap in manually. As the flap retracted the vibration of the airfoil lessened, until it was almost as quiet as the simulator had been. Arun was starting to feel the effort his muscles were making, but kept going until the flap was fully retracted. It took only a few moments to install the new actuator and connect it to the building management system. Cahil ran a few tests then indicated to Arun it was safe to remove the manual adjuster.
After closing the access panel, Cahil motioned Arun to look at the features of the airfoil. “In the safe position, all the ventilation is shut off, of course, but you see the way the intakes are positioned?”
“As the airfoil moves they bring fresh air into the building, correct?”
“Yes, the airfoil moves to pick up the most airflow possible and regulate to the flow we need at any given time. In the middle of the foil are the heat exchangers that dissipate the heat generated in the building. The flaps just like the one we repaired have the exhaust air, and a good wind will generate enough suction that we don't even need fans to move the air out.”
Arun looked at the areas Cahil indicated. Here on the side of a building with the wind in his face, it all became real in a way the simulators could never reproduce. Here he could feel the forces, understand the power of the wind, and realize how it could move air through such a large building.
“Do you run the fans at all?” Arun was curious.
“Sometimes, it depends on how much wind there is,” Cahil answered. “But even on a still day, the heat rising from the city below creates some air movement. Are you ready to go?”
Together they slid back off the airfoil and retreated to the safe line outside of its range of movement. Arun had removed the pull line from the airfoil and was coiling it up as Cahil released the safety locks using his wrist pad and put the airfoil back into operation. Moving smoothly now, Arun watched the foil position itself and the flaps extend in unison to catch the wind.
“Gives you a good feeling, doesn't it?” Cahil smiled.
It did give Arun a good feeling. Looking out across all the towering buildings reaching skyward on the island of Manhattan, he thought he had a lot to look forward to, dancing skinside on the towers of the wind.