“First, let’s take your rotating disk. That would be a lot simpler to build than the stationary disk with variable jet nozzles. With a disk rotated at high speed you get a tremendous lift, whether it’s slotted or cambered, as long as there’s enough air to work on.” “The helicopter principle,” I said. Redell nodded. “The most practical propulsion would be with two or more jets out on the rim, to spin your rotating section. But to get up enough speed for the jets to be efficient, you’d have to whirl the disk mechanically before the take-off. Here’s one way. You could have a square hole in the center; then the disk launching device would have a square shaft, rotated by an engine or a motor. As the speed built up, the cambered disk would ride up the shaft and free itself, rising vertically, with the jets taking over the job of whirling the cambered section. “The lift would be terrific, far more than any normal aircraft. I don’t believe any human being could take the G’s involved in a maximum power climb; they’d have to use remote control. When it got to the desired altitude, your disk could be flown in any direction by tilting it that way. The forward component from that tremendous lift would result in a very high speed. The disk could also hover, and descend vertically.” “What about maneuvering?” I asked, thinking of Gorman’s experience. “It could turn faster than any pilot could stand,” said Redell. “Of course, a pilot’s cockpit could be built into a large disk; but there’d have to be some way of holding down the speed, to avoid too many G’s in tight maneuvers.” “Most of the disks don’t make any noise,” I said. “At least, that’s the general report. You’d hear ordinary jets for miles.” “Right, and here’s another angle. Ram jets take a lot of fuel. Even with some highly efficient new jet, I can’t see the long ranges reported. Some of these saucers have been seen all over the world. No matter which hemisphere they were launched from, they’d need an eight-thousand-mile range, at least, to explain all of the sightings. The only apparent answer would be some new kind of power, probably atomic. We certainly didn’t have atomic engines for aircraft in 1947, when the first disks were seen here. And we don’t have them now, though we’re working on it. Even if we had such an engine, it wouldn’t be tiny enough to power the small disks.” “Anyway,” I said, “we’d hardly be flying them all over everywhere. The cost would be enormous, and there’d always be a danger of somebody getting the secret if a disk landed.” “Plus the risk of injuring people by radiation. just imagine an atomic-powered disk dropping into a city. The whole idea’s ridiculous.” “That seems to rule out the guided-missile answer,” I began. But Redell shook his head.