by Eric Flint
Modern hot air balloons use propane burners. The propane is compressed to liquefy it and when released became a gas once more.
Propane came from natural gas. However, while the Chinese did make use of natural gas in Sichuan Province as a fuel for boiling brine, those natural gas wells were hundreds of miles away. And anyway, the Chinese hadn’t tried separating propane out from the other gases, let alone liquefying propane.
So if the hot air balloonists from Grantville didn’t want to be limited by how many tanks of propane they took to China, they needed to burn a different sort of fuel. And so some experimenters had modified the propane-burner design so it could burn a less volatile fuel, like kerosene or even diesel oil, under pressure. Animal and vegetable oils could be used in place of diesel oil, with a bit of tweaking of the atomization system.
“Okay, all four burners are working, let’s head off to bed,” said Jim.
* * *
It was perhaps an hour before sunrise. Jim was out first, and was pleased to note that while there was a bit of wind—smoke was drifting to the northeast—the leaves on the trees weren’t moving. So, Beaufort scale 1, one to three miles per hour. Of course, Jim didn’t have the benefit of a true weather forecast, but the clouds were few and unthreatening, and the barometer appeared to be holding steady. That was a nice surprise, as it seemed to rain every other day in Xiamen in June.
Jim was captain of the ground crew; Mike was to be the pilot. And his passenger was to be their patron, Zheng Zhilong.
The chosen launch site was a large field on Jinmen Island, some yards from the dwelling that they were using as a base of operations. Jinmen Island was dumbbell-shaped, on nearly an east-west axis. The cove in which Zheng Zhilong had defeated a Dutch naval squadron in October 1633 faced south. The launch field was on the southwest arm of the island, with a coastal ridge sheltering the balloon from the southwest monsoon. The city of Jiamen lay to the west, about fifteen miles away. Xiamen itself lay on the west coast of another island, and a smaller island lay between Jinmen and Xiamen.
Jim, Mike and the ground crew put together the basket, secured the uprights, and attached the load frame. Then they mounted the burner on top.
“Burner test, everyone back,” said Jim. There was a rush of blue flame. Some of the spectators jumped back, even though they weren’t in harm’s way. Jim turned off the fuel valve and the flame petered out.
“Okay, it works. Let’s lay it down.” Mike and the others came over and gently laid the basket over on its side. The crew attached the envelope to the basket, and streamered it out, directly away from the top of the basket. Four lines ran from the basket to heavy anchors—cannon barrels. One was the short tie-off, which the pilot would release when he was ready to launch. The others were the three tethers. Since they didn’t want the balloon to make a free flight and perhaps create a disturbance, they would remain fastened until the balloon was safely deflated. They had several lengths of tethers at their disposal, which were over four hundred feet long. Since the tethers would be running up at a forty-five-degree angle, the balloon couldn’t rise higher than about three hundred feet, and Jim didn’t intend to go above two hundred feet.
Two sailors grabbed the lines attached to the mouth of the balloon envelope with gloved hands and held the mouth open. Two more held onto the crown line, that is, the line attached to the top of the envelope. The purpose of the crown line was to steady the balloon if there was a wind, or if the balloon started rolling or otherwise misbehaving.
Jim and Mike placed the blower to one side of the basket, aimed at the mouth of the balloon, and with the engine’s exhaust pipe pointing away from the basket.
Jim started it up, and watched the little ribbons attached to the skirt of the mouth. Some were blown in by the fan, others blown out by escaping air.
“Um, too close.” He shut down the fan and slid it a few inches further away. He started the fan up again, and this time all the ribbons were blown in. And the grass to the side of the mouth was not moving.
“Just right,” Jim commented. He switched the fan back on, put a foot on the base, and held the top rail with both hands.
“That is one of the propellers you have told me about?” asked Zheng Zhilong. He had to shout the question.
Jim nodded. “It is, but this one is designed to move air, not water.”
Gradually, the balloon filled with air. It was cold air, of course. As it filled, Mike walked around, making his preflight check. It would, after all, be his life on the line. The sailmaker walked with him, making his own inspection, and at the last removed the ribbons.
Mike gave Jim a football “T for timeout” signal. It meant that cold inflation was just about complete.
“Mike, you are in command,” said Jim, and he reduced the blower to half throttle.
“Prepare for hot inflation,” Mike warned the ground crew, and waited for them to nod acknowledgment. Several of them came over and stood on either side of the basket, ready to hold it down if the balloon started to lift off before Mike was ready.
Mike knelt in the space between the basket and the burner, so he could access the burner controls. He angled the burner a bit upward and sighted along it, confirming it was pointing down the throat of the envelope. He pushed down repeatedly on the pump handle, pressurizing the fuel, and lit the pilot light.
“Test blast!” said Mike, and opened the fuel valve on the burner. A blue flame jetted out; Mike confirmed that it was clearing the fabric and the sailors on throat duty.
“One thousand one, one thousand two…” Mike counted to himself. After six seconds, he shut the valve for three seconds, giving the fabric, not to mention the sailors, a chance to cool down.
Zheng Zhilong tapped Jim’s shoulder. “In the days of the Song, our armies used a Pen Huo Qi, a Sprayer of Fiery Oil, against the Mongols. But I think it made a different kind of flame.”
“The burner for the balloon breaks the oil up into extremely small droplets; when they are ignited, they are turned immediately into gas. It is the burning gas you see here.”
“Gas?”
“It is a substance like air, but with different properties. This gas burns. There are other gases that burn, too, like the gas that rises from swamps, or the firedamp in a coal mine.”
As Mike continued the intermittent blasts of fire, the balloon started to rise.
He turned in Jim’s direction and made a throat-cutting gesture. “Blower off!”
Jim turned off the supply of fuel to the blower engine. The fan would keep running for a minute or so, turning ever more slowly.
The throat crew gently released the balloon and came around to hold the back of the basket as it tilted backward. At the same time, the crown-line crew allowed the crown to rise, but not too quickly.
Jim was pleased to see the ease with which the men went about their work. He and Mike Song and several other members of the mission staff had been trained in balloon operation prior to leaving Grantville, but most of the ground crew were simply sailors. Obviously, they had experience handling lines for sails and they’d gotten some training before the Rode Draak left on the mission in September 1634. But since then, on the voyage itself, they could only give the crew some reminder lectures and practice some aspects of the ground handling. The balloon could not be safely inflated on board a ship not designed for the purpose.
But all seemed to be going well. The inflation was proceeding as smoothly as it had during their test run the day before, even though the crew knew they had to impress their distinguished visitor.
Once the fan of the blower had stopped turning, Jim tilted it backward and slid it back some feet, well away from the basket. In the meantime, Mike stood up and adjusted the burner orientation to keep it centered on the mouth of the envelope.
When the basket was inclined perhaps thirty degrees from the horizontal, Mike stepped back into it, and the throat crew rotated the basket upright. The balloon was also vertical, and bobbing with its mouth perhaps a foot
away. Mike pointed the burner straight up and pulled in the mouth so it was directly over the burner. He then tied the mouth to the frame so it would stay that way.
The crown-line crew brought the line to the pilot, who fastened it to the frame, and they joined the throat crew around the basket. “Weight on!” he called, and all four put all their weight on the top of the basket, while keeping their feet on the ground.
It was time for Zheng Zhilong to board. Mike offered him a hand, but Zhilong declined.
Mike bowed to him once he was settled in the basket. “Admiral Zheng, there’s something very important that I tell you. Please don’t take offense, but this balloon is my ship and I am the captain. You must obey my orders.”
Zhilong smiled. “It appears that sailing the sea and sailing the air have much in common. It will be as you direct.”
Mike gave the burner a one-second burst and studied the movement of the balloon.
“Light hands!” The ground crew eased up, leaving their hands on top of the basket so that they could put weight back on quickly if so commanded.
Mike gave the burner another short burst. The balloon rose off the ground, but too quickly for Mike’s taste. “Weight on!”
He waited a few seconds. “Light hands!”
The balloon remained steady, the basket perhaps a foot above the ground.
“Ready?” he asked Zhilong.
The admiral pointed up at the sky.
“Hands off!” The crew let go of the basket and backed away from it.
Mike released the tie-off, and gave another short burst with the burner.
Slowly, the balloon rose into the morning air.
“We are already higher than the crow’s nest on the tallest ship I have ever set foot on,” marveled Zhilong.
“That’s what, seventy feet? The tethers will let us go several times as high, although I don’t want to go so high that the ropes are taut.”
As Mike answered, he briskly opened the burner valve, and three seconds later, closed it again. The balloon, which had started to descend, resumed its ascent.
“How do you decide how often and how long to apply the flame?” asked Zhilong.
“I like to make each burn exactly the same—I aim for a three-second full burn—and just adjust the frequency of burns to the situation; how high up we are, how fast are we ascending or descending, and where I want to end up.”
“Ah. We are higher now. It seems to be windier, too.”
“We’re at about two hundred feet now. Wind speed tends to increase with altitude. But just so you know, the only reason we feel the wind is that we are tethered. If the balloon were flying free with the wind, we’d accelerate up to the wind speed, and then, traveling with the air current, we’d feel nothing.”
“So why doesn’t that happen with a ship?”
“There’s more resistance, so you probably don’t reach a ground speed of much more than maybe half the wind speed.”
Zhilong leaned over the railing of the basket, looking northwestward, toward the channel lying between Jinmen and the island immediately to its west. “There! That’s one of my ships!”
“How can you tell?”
“Look at the foresail.” The foresail bore the character “Zheng.”
“So how far can we see now?”
“We’re at two hundred feet, so…I’d say a little over seventeen miles. Weather permitting, and no hills in the way, of course. With a thousand-foot single tether, we could see almost forty miles.”
“So let’s go higher!” said Zhilong. “At least to the limit of the tether.”
“It’s not a good idea. If we released the tether and free-ballooned up to eight thousand feet, which is as high as lowlanders like us can go without risking mountain sickness, we could see over one hundred miles. Forgive me, Admiral, but this is a test flight, and you are an important personage. I’ll feel a lot happier once you’re safely back on solid ground.”
Zhilong smiled. “I understand. Not good for business to have an admiral fall over the side, whether at sea or in the air. But first, may I try a burn myself?”
“Be my guest.”
Chapter 23
Zheng Zhilong’s office
Zheng family compound
Anhai
Jim Saluzzo cleared his throat. “Admiral, one of the issues that we’ve debated a lot is how to persuade your countrymen, particularly those in positions of power, that we—the residents of Grantville, that is—are from the future. As opposed to just people with some advanced technology, or magical powers.
“Now, back in Europe, anyone who wanted to could visit Grantville. They could see the Ring of Fire and how it formed a perfect circle, about six miles in diameter, in which the landscape was of a kind, but completely different from the German landscape surrounding it. For that matter, they could speak to the Germans living nearby, in Rudolstadt and Badenburg, who could confirm that the Ring of Fire had displaced the countryside that had been there before.
“And they could visit Grantville and see our mines, fields, streets and buildings, our people and our books and gadgets. Everything they saw on such a visit would have been consistent with our story.
“But you didn’t visit Grantville. Nor did any of your countrymen. Yet you were, Yan told us, persuaded that Grantville was a town of the future even before you met us. What convinced you?”
Admiral Zheng Zhilong had worn a peculiar half-smile throughout Jim’s long lead-up to this question. “Persuaded is perhaps too strong a word. I had learned enough so that I was prepared to consider the possibility. You see, I had faith that if Europeans who would have wished to believe otherwise were convinced that you were from the future, that such might indeed be the case,” he answered. His half-smile broadened to a full one.
“What do you mean?”
“I first heard of Grantville from the Portuguese in Macao. The lifeblood of Macao is its role as intermediary, trading Japanese silver for Chinese silk, taking advantage of the Chinese ban on direct trade with Japan. And Macao’s special status in China is protected by the Jesuits at the imperial court. They fear Grantville because of its promotion of religious freedom, its advanced astronomy and other technologies, and its knowledge of the future, all of which threaten to undermine the Jesuits’ present advantages.”
“The Jesuits speak openly of this to you?”
Zhilong smiled again. “I have been able to secure copies of some of their correspondence with Rome. And to obtain the services of individuals who can translate it for me. It is also of course of great interest to the Macanese that your histories of the future say that in 1639 the Portuguese were forbidden to visit Japan, and that in 1640, the House of Braganza led the Portuguese into a rebellion against Spain.”
“I am not so sure that will still happen,” said Jim. “That is, the Spanish know about it, thanks to the same histories, and for all I know, they may have imprisoned every member of that house. And that, of course, is another complication: The very transfer of Grantville to the past changes what the future holds in store for us.”
Zheng Zhilong shrugged. “For centuries, even millennia, rulers have sought out those who claimed to be able to predict the future. The question, then, was whether a ruler could change his fate with such foreknowledge. Some thought that this could be done; I have heard that your European astrologers say, ‘The stars dispose, they do not compel.’”
“Giving them an excuse if events don’t unfold as predicted,” Jim complained.
“I don’t doubt it. But the Spanish also accept that Grantville is from the future, albeit they think its transposition to be the work of the Devil. I have seen documents seized from the office of the governor-general of the Philippines when Manila fell. And they accept this even though the books of Grantville reveal that Spain lost the Netherlands and Portugal, and then came under Bourbon rule.
“For that matter, the Dutch also believe in the story of the Ring of Fire. But they are happy with what your history books say abo
ut them—they won independence from Spain, didn’t they, in your past?—and they will probably learn your new technology faster than anyone else. So the Portuguese, the Spanish and the Dutch have all had the opportunity to examine your town and its works, and are convinced, however reluctantly, that you are from the future.”
“This is all very gratifying,” said Jim. “But most Chinese officials aren’t going to have your understanding of the Portuguese, the Dutch and the Spanish.”
“No, they haven’t lived and worked with them, as I have.”
Jim sighed. “So how do we convince those officials that we are from the future?”
“Is it really important that you do so?”
“We thought that if we were accepted as such, it would earn us special treatment.”
“It might. You hope for special diplomatic privileges, but it could just as easily be imprisonment in Fengyang, along with the inconvenient imperial relations already confined there.”
“What would you do, in our shoes?”
“Me? Claim that you have magical powers. It works for the Taoist monks and the Tibetan lamas, and you have more miracle-making ability than they do.
“In fact, you can say that back home, your people have magic mirrors that show images of the future and the past. That would be much more believable than saying that you are actually from the future; we have no legends of people traveling back in time. Just be sure to say that all of the mirrors are back home. That way, the government can’t demand you demonstrate them or turn them over as gifts for the emperor. Or you can say that you are from another world, where time passes differently than here, which is why your technology is so advanced. The Buddhists believe that there are many worlds.”
“Well…I’d rather speak the truth.…”
“A propensity to tell the truth can be something of a handicap, in my experience.”
* * *
Soon thereafter, Jim took his leave; he had a date with his wife. Zheng Zhilong was left alone to muse over recent events.