by John McPhee
GOLDSTEIN, in the nineteen-twenties, solved the differential equation for the flow field in the wake of a propeller, and Goldstein was ignored for twenty-five years. For water, as for air, propeller design before Goldstein had been entirely empirical, and it remained almost wholly so until the advent of the big computers, when people were finally able to figure out what Goldstein was trying to tell them. Theodorsen embraced Goldstein’s theory, and expanded it. Rose, in his turn, added touches of his own, and assumed preëminence among propeller designers in the United States.
In the most efficient of propellers, the vortex sheets move back as if they were solid. Behind Aereon 26’s lemonwood prop, the vortex sheets were apparently moving back in shreds. Hence, the 26 could get off the ground but not much farther into the air. Perhaps Henry Rose could solve the problem. Rose could offer no guarantees, but he could at least give Aereon a propeller that was exactly designed. It would cost five hundred dollars—payable to Rose’s employers, the Sensenich Corporation, of Lititz, Pennsylvania. A compound of low buildings beside Lancaster Airport, Sensenich looked like an old lumberyard that had seen its boom. A man from Sensenich was on the road all the time, in northern New York and in Canada, hunting birch and maple. Wood that grew in cold air was particularly hard. The wood was dried in Pennsylvania until ninety-three per cent of its moisture was gone. Then it was cut, planed, and studied—for defects, for grain angle, for grain straightness. Half was rejected.
It was Henry Rose’s decision that Aereon’s propeller should be made of Canadian yellow birch, and that it should be four-bladed. Rose was limited to a forty-eight-inch diameter, because the engine was so light and small. Most light-airplane propellers were half again as large. This one would be a miniature, more or less, of the big four-bladed props that pushed the Hindenburg. There was nothing conscious in the choice. Rose had no idea what the Aereon Corporation was about. He was curious, but had not been told. He had been given only the essential facts—of power, of weight, of engine rotational speed, of the vehicle’s design speed. Air flows over a propeller in much the way that it flows over a wing, with the difference that the propeller moves variably faster from hub to tip. Rose, out of Goldstein by Theodorsen, had to find the optimum blade-load distribution.
The propeller blank was a wooden cross made of birch laminations held together by resorcinol glue, the only glue officially rated waterproof. Specimen propellers had been left on the Sensenich roof for years and years, rotting away, until all that was left was the resorcinol glue. Marks made at intervals on the wooden blank were known as Stations Along the Blade. For each station, Rose had designed a brass template. Carving had to conform precisely to the templates. There were hundreds of carvers at Sensenich during the Second World War. There were two now—tall middle-aged men with glasses, Mel Eichelberger and Edwin Miller. Metal had long since become the material of most propellers. But wood vibrated less and never had fatigue. Metal propellers were more efficient, but for some things metal would not do. Metal required forging and dies. For experimental purposes, no one could afford such a die. Eichelberger and Miller looked like cobblers. They carved by hand. They used drawing knives, with two handles, and powered abrasive drums. They carved by feel. They felt the fairing of the blade. And they were watched by Henry Rose, a kindly, gentle, and scholarly man, tall, with dark-rimmed glasses, and an insignia of rouge in his cheeks.
Rose had grown up in this milieu, and had first met the Sensenich brothers forty years before. The brothers, as boys, had carved an empirical propeller from a walnut bedstead, attached it to a motorcycle engine, attached that to a sled, and skimmed across the snow down the mile-long lane from their family’s farmhouse to their mailbox at the county road, returning with the Saturday Evening Post. They built their snowmobile because they hated trudging for the mail. They whirred along on the ice of the Susquehanna River. They carved new props for Jennies from the First World War, because there were no surplus props. The Sensenichs were Mennonites, out of step with custom. Their people went along the roads of rural Pennsylvania in horse-drawn black carriages, ignoring automobiles, rejecting such aspects of the century, while the brothers Harry and Martin Sensenich made fortunes in aeronautics. God’s ways were hard on their family. Their father was killed by a train. Their mother died in a fire in her kitchen. Their brother was kicked to death by mules. In 1944, the Sensenichs carved forty-three thousand propellers.
The tapering blades of Aereon’s propeller, as they took shape, spiralled with the grace of lanceolate leaves. The templates fit perfectly the Stations Along the Blade. The propeller was dipped in sealer and sprayed with varnish. The leading edges were trimmed with brass, which was riveted into the wood with copper. Two coats of polyurethane covered all. The grain shone through. The propeller was ready. A work of mathematics, not of art, it seemed almost too beautiful to hang on a wall. Rose sent it off to New Jersey, wondering (a single, pusher propeller? so small?) what on earth it was for.
THE PROPELLER was ready but Aereon was not, since Miller had scarcely enough money to pay Sensenich and none at all for renewed tests. His fundraising efforts failed totally. The market environment was bad, he explained. The 1970 year-end sell-off was beginning. Christmas was a head wind in itself, against which he could not make progress. His consultants were drifting into other work, but Miller refused to go on with the tests until he had what he called “funds identified in hand.” With the 26 hidden away again in its Sheetrock box at Red Lion Airport, forty miles from NAFEC, Aereon went into hibernation. John Olcott, the test pilot, speaking to Miller on the telephone, said to him, “I just sometimes wonder if you really want to see the final results of these tests.”
“How can you say that when you know I’ve put all these years and all my own money into this project?” Miller said.
Olcott said, “I don’t know. I’m just wondering, that’s all.”
Miller went off to Urbana, Illinois, to represent the Scripture Union at a triennial convention of the Inter-Varsity Christian Fellowship, the purpose being to persuade twelve thousand assembled students to be foreign missionaries. Miller had not missed one of these convocations since he was in college. Back in New Jersey, he continued the hunt for money. Budgeting pessimistically in terms of weather and time, he figured he needed fifty thousand dollars for just enough additional flight tests to show, one way or the other, the pertinent validity of the Aereon concept. Many weeks went by. Three existing shareholders finally gave him forty-six thousand dollars. It would do.
February 24, 1971, about half an hour before dawn, Buddy Allen, of Tabernacle Township, who was getting a hundred dollars for the job, started to move his flatbed trailer out of Red Lion. Aereon 26 was chained down to the bed and camouflaged as before, with newspapers taped over all its markings, more newspapers over the canopy, and a tarpaulin shrouding the engine and the prop. The light in the east was medium gray. An acre of now frozen mud around the apron of the little hangar had been striated with tire ruts, and the ruts were white with panes of thin ice. The big truck cracked the ice as if it were driving slowly over bottles. It circled a biplane and lurched up onto a blacktop road.
A state-police car led the way, followed by Everett Linkenhoker’s station wagon with a big sign on the roof—“WIDE LOAD.” Then came the 26, its wide rear reaching out on either side beyond the macadam; then Miller, in his Mercedes (I rode with him); and, finally, Paul Shein and John Weber, with another roof sign—“OVERSIZE LOAD.” Miller remarked that the procession reminded him of a state funeral. A fin hit a juniper bush. The corresponding fin on the other side hit a branch. The first fin just missed a road sign, skinned a mailbox, and barely missed poles and trees, more poles, more palisade trees. The amperes were rising in Miller’s nerves. The Mercedes’ radio was on, and a concerto was coming out of it. Miller snapped it off. He felt guilty. “I don’t like to shut off classical music,” he said. “It somehow seems impolite.”
The road widened out into Red Lion Circle, and the procession began
to move south on Route 206, a wider highway, but still two-lane, with the 26 reaching far out over the center line and far out over the right shoulder. Dawn came. The state trooper waved farewell. Another trooper would meet the 26 near Hammonton.
“This is great,” Miller said. “Wintertime. No one is out wandering around in their yards in the early morning.” A pickup truck passed the 26, going down the far shoulder. A blue Ford and a small red van followed the pickup, then various automobiles. Miller watched them all suspiciously. Anything with a long antenna made him nervous. He could see the enemy and the curious coming in in pincers: Boeing, Douglas, Lockheed, The New York Times, the Cleveland Plain Dealer, the New Orleans Times-Picayune. The procession was moving at fifteen miles an hour. Two big tractor-trailers and several other vehicles were bunched up behind. Huge trucks were now coming the other way, raging north, pressing up the long straightaways at seventy miles an hour, dropping six wheels onto the wet shoulder and spraying sheets of water as they rocked the 26 with blasts of wind. Some of the big diesels missed the aerobody’s anhedral by inches. One slight contact and the 26 could be ripped in half. Linkenhoker, in front, moved his station wagon over a little more into the path of the trucks. He all but stuck his left front fender into them. The drivers leaned out and shook their fists. They were on their way to Whippany, or wherever, and they did not like the wide load coming into them. They could hardly have known or imagined that the ambition of the 26 was to grow large enough to swallow them and their trucks and carry them through the sky.
After a time, the big diesels that were following the 26 made their move and passed, going off the road on the far side. Their sudden absence in Miller’s rearview mirror revealed a brown Plymouth sedan. Miller kept an eye on it for a while, then became alarmed. The Plymouth was making no attempt to pass, even though the road ahead was straight and free. “We’ve got a follower,” Miller said. “He’s lagging way behind, so other people can get by him. He definitely does not want to pass us. What is his plate number?”
“KMN 260.”
“Perhaps we should write that down.”
KMN 260 followed the 26 for several miles and then passed, and then stayed in front for a while, pacing the procession, before moving on out of sight. “I imagine he took pictures,” Miller said, with a resigned sigh. Miller seemed to accept this calmly, with experienced stoicism. The cortege moved on, now doing twenty miles an hour. Miller continued to watch closely the road, the traffic, the landscape. Blueberry fields came up on the left, and a peach orchard on the right. His glance searched through the orchard as if there were transmitters hanging from the branches of the trees. The 26 approached Hammonton Circle. A state trooper was waiting there, on foot, in a forest of warning signs. He had cleared out all traffic, and he directed the 26 to go through the circle clockwise, a more direct route than the orthodox one, and less endangered by the razor-edged signs. Passing him, Miller gave the trooper a military salute. The trooper returned it. The procession headed east toward NAFEC, on the White Horse Pike. The road was now larger, and more popular—four lanes, undivided. The 26 filled its side, but did not cross the center line. Traffic amassed behind—ten, eleven, fifteen cars. Miller shuddered. The third car back was a brown Plymouth sedan—KMN 260. Perhaps the driver had gone off to mail pictures to Seattle and had now come back for more. So intent was Miller on the Plymouth in the mirror that he nearly plowed into the 26. The procession had now grown to some twenty-five vehicles, and there were signs of impatience, scattered horn-play. Suddenly, Pennsylvania 37C 109 had had all of this that Pennsylvania 37C 109 was going to take, and Pennsylvania 37C 109 leaped out of the pack, crossed the double yellow line, vroomed past the 26, and shot away. KMN 260 also jumped out of the pack and went around the 26 like a flicker of light, chasing Pennsylvania 37C 109 in a race that lasted fifteen seconds and ended with the Pennsylvania car stuffed into the roadside, its driver under arrest. KMN 260 was an unmarked patrol car of the New Jersey State Police. Its occupant, who was having a morning and a half, was the same efficient fellow whom Miller had saluted only minutes before. At the first sizable turnout, an abandoned drive-in, Buddy Allen removed the Aereon from the highway and loosened up the traffic. Moments later, the trooper pulled up beside the 26. He got out of his car, snapped shut his summons case, and, with a booming laugh, inspected the aircraft.