"Its direction and velocity would be governed by the number of nozzles
operating, the power applied, and the angle at which they were tilted.
They could be pointed toward the ground, rearward, in a lateral
direction, or in various combinations.

"A disk flying level, straight ahead, could be turned swiftly to right
or left by shifting the angles of the nozzles or cutting off power
from part of the group. This method of control would operate in the
earth's atmosphere and also, using rocket power, in free space, where
conventional controls would be useless."

The method he had described was not the one which D------ had
outlined.

"What about a rotating disk?" I asked the N.A.C.A. man. "Suppose you
had one with a stationary center, and a large circular section
rotating around it? The rotating part would have a camber built into
it, or it would have slotted vanes."

He gave me a curious look, "Where'd you get that idea about the
camber?"

I told him it had come to me from True.

"It could be done," he said. "The slotted-vanes method has already
been tried. There's an engineer in Glendale, California, who's built a
model. His name's E. W. Kay."

He gave me a few details on how a cambered or slotted-vane rotating
disk might operate, then interrupted himself to ask me what I thought