Grantville Gazette 38

where on the wing. Then the fan was turned off and the flaps were adjusted, and the process started again. After they were done, they had the Reynolds number by working backwards from the point of non-laminar flow.

That, and a whole lot more data that could be fed into a computer spreadsheet program to give solid estimates of lift and drag over a range of speeds and angles of attack. They added weights to different points on the model, adjusting its center of gravity to include the weight of things like engine and pilot. Maneuverability, carrying capacity, takeoff speed, and more, were provided by the wind tunnel tests of the model in combination with the knowledge bought by thousands of lives over a hundred years in that other timeline. It seemed to Willem complete, and offered a level of confidence that surpassed that even of shipwrights. And compared to what the Wright boys, Curtis, Sikorsky, or even Douglas had had to work with, it was complete.

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It took a few days to process the data. Well, it took a few days to get around to processing the data. It took a couple of hours to input the data and the computer took microseconds to do the calculations. And it didn't take Hal Smith much longer to interpret the results.

The faster the plane was going, the greater the lift. As was standard but, like the weight, the lift was centered well back on the plane. In fact, even at fairly low speed, the center of lift was farther back than the center of gravity, which meant that in flight the Arrow was going to be nose heavy. Because of ground effect, that was even more of a problem on takeoff and landing. Because the ailerons were actually elevons, combining the function of both elevators and ailerons in one control surface. And because it was a tailless delta, you couldn't go flaps down for takeoff and landing. Not without shoving its nose into the ground. So they would need to shift as much of the heavy bits as they could toward the back of the aircraft.

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He discussed his changed designs with the boy Darius because he had been the researcher for the whole project. 'Herr Smith doesn't much care for the delta-wing design,' Willem told Darius with another of his half-grins. He had just returned from a very expensive half-hour consultation with the only aeronautical engineer on earth. When not working for the State of Thuringia-Franconia Air Force, Hal Smith-for a piddling five hundred American dollars an hour-did consultations with prospective aircraft designers. And to spend that five hundred dollars an hour, you made an appointment and waited your turn.

'Well, he's probably right, sir,' the youngster admitted. 'I know they look cooler, but that doesn't necessarily mean they're better.'

'I know, Darius, but 'cooler'-did you say?-looking airplanes may have a higher sales price because they look better, faster, or more dangerous,' Willem said. 'We aren’t the only ones building aircraft and it's generally better to stand out from the crowd at least a little.'

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Armed with the information from the wind tunnel tests and analysis, Willem didn't abandon the delta, but did adjust his design. He did several things to move weight toward the rear of the aircraft. The gas tank, storage and armaments were moved back, but he wanted the pilot as far forward as he could manage. That just left the engine, the heaviest single part of the aircraft. He considered the idea of a center-mounted engine and a long drive shaft, which might have worked, except that the drive shaft would then go right through the small of the pilot's back. And that left a pusher, a plane with the propeller in back. Well . . . why not? They were supposed to be quieter, anyway, not that Krause had ever been in a pusher, but that's what the books said. Besides, the Dart, even if its engines had been spread throughout the body if the plane, the thrust at least had gone out the back. The Krause Arrow would be a pusher. That simplified things greatly. The engine and prop would be right at the back, with the gas tank just in front of the engine. The cargo and/or weapons would be between the gas tank and the pilot. The pilot would be as far forward as he could be and still have room for the control runs. Then it was off to the carpenter's shop to turn the designs into an airplane.

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'Plywood?' Willem asked.

'That's what the up-timers call it. Take a thin sheet of wood, not a lot thicker than a sheet of paper, then a thin layer of glue. Another thin sheet of wood laid out crosswise to the grain of the first sheet, more glue, another sheet, still more glue, still another sheet, constantly changing the direction of the grain. Then compress it all and let it dry. The up-timers call it plywood; we call it laminated wood and it's what the up-timers call a composite material. Whatever you call it, it gives you wood that won't split along the grain because the grain isn't all going one way. Wood that spreads the stresses placed upon it in ways that normal oak or ash can't.'

'What about spruce?' Willem asked. 'The books mention aircraft spruce.'

'Yes, but what is aircraft spruce?' Giuseppe Bonono asked. 'All I know is that the books talk about spruce in the Americas. I know there is spruce in Europe. It's light and fairly strong, easy to work. But I don't know if it is this airplane spruce that they are talking about. It's pretty clear that not all spruce is airplane spruce. But I know about laminated wood. I know things I can do to make sure that it's strong and light.'

'All right. The Convair Delta Dart was made out of aluminum, after all, and we aren't going to get that.'

They went on to talk about the structure of the wings and the internal supports of the fuselage. Where the control runs would go and how they would be attached. What kinds of glues would be used where.

'What about the skin? Laminated wood . . . even very thin it’s going to be heavy,' Giuseppe warned.

'Doped canvas,' Willem told him. 'I have Pierre Trovler working on finding the right canvas and doping agent. The book, Aviation 101, second edition, suggests that the frame be lacquered before the canvas is applied. Apparently raw wood and canvas aren't a good combination.'

****

The Arrow wasn't the only work of the carpenters, nor of Pierre Trovler. They had chairs and desks to make and portraits and landscapes to paint, respectively, and Willem Krause wanted to see and understand everything that went into the construction and maintenance of his aircraft. To Giuseppe and Pierre, this seemed simply a reflection of Willem's obsession with aviation.

In part it was that, but Willem, having determined that he would find his home among the lords of France and Austria not the peasants of the USE, intended that he would know all that was needed to see to any repair or even rebuild the Arrow. He noted the interest that Gemma showed in him, and in other circumstances he would have taken advantage of it. But not here. Not now. Not among peasants who thought themselves his equal. It was too risky. The girl would have to make do with a clumsy farm boy to lose her innocence.

Still, gradually, amid impatient letters from Saxony, the Arrow did come together and became an aircraft. In all considerations save one. It had no engine. Engines, even the heavy engines of pickup trucks and vans, could not be had for love or money. Half a dozen companies were making down-time produced engines and each and everyone was sold before it was built.

A rich peasant could get an engine. A rich burgher from the Netherlands could arrange the creation of a company to make them for his airplanes. But a noble of Germany had to wait his turn. Money wasn't enough. You had to have connections.

The plane was finished. The months dragged on. No engine came to Willem Krause.

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'Where is my airplane?' John George of Saxony demanded in the fall of 1634. 'Krause has had over a year. There are dozens of airplanes by now and I don’t have even one.'

Karl Gottlieb knew better than to point out that he had harbored doubts about the project from the beginning. John George didn't care for 'I told you sos.' Instead he simply said, 'I don't know. I could send someone to check up on Willem Krause.'

'Send someone?' John George asked. 'No! Go yourself. I want to know where my money is going. Gustav Adolph and that jumped-up peasant Stearns are pushing things in the CPE and I won't have the Swede as overlord of the Germanies.'

Karl wasn't John George's spymaster, but he also wasn't a field agent. He was the assistant spymaster for Saxony and really too well-known to be sent to Grantville. But that was now beside the point. He had his orders and the Elector had a whim of iron.

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