Wikipedia’s attempt is boring:
A helicopter is a type of rotorcraft in which lift and thrust are supplied by rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward, and laterally.
Britannica.com is similarly uninspired:
Helicopter, aircraft with one or more power-driven horizontal propellers or rotors that enable it to take off and land vertically, to move in any direction, or to remain stationary in the air.
Even World Book’s current entry, accessible on their website with a free trial, is utilitarian:
Helicopter is an aircraft that is lifted into the air and kept aloft by one or two powerful whirling rotors. A helicopter rotor resembles a huge propeller that is parallel to the ground. However, the rotor is actually a rotating wing.
But The World Book Encyclopedia 1964 edition––now there’s a set that had an H volume worth perusing at leisure! Turn to page 162 if you’ve got a copy lying around.
Here’s how its helicopter entry begins:
HELICOPTER, HEL uh KAHP tuhr, is an aircraft that can do almost all the tricks of the flying carpet in Arabian legends. It can go straight up or straight down. It can fly forward, backward, or sideways. It can even stay in one spot in the air and turn completely around. The helicopter has several nicknames. They include flying windmill, whirlybird, eggbeater, and chopper. These nicknames refer to the whirling motor that makes the helicopter fly.
I’d call that a diversion of the page. The entry captures the wonder of the machine, even if it takes a couple more sentences to transition to its whirling motor.
What inspired it?
Unlike all of the other entries for helicopter that I quoted, the 1964 article also credits a single author, Igor Sikorsky. As it turns out, something of his background is known to us still. When he was a child in Russia, he read the Jules Verne novel The Clipper of the Clouds and dreamed that he might one day create the fictional flying machine that it described.
He built his first helicopter in 1909.
“It crashed before it got off the ground,” his son told a newspaper. “So he built another one. It too was a failure.” Still, he would often quote Jules Verne: “Anything that one man can imagine, another man can make real.” And in time, he saw other men develop early helicopter prototypes that lifted off the ground without crashing.
Then in 1939, having moved to America, he developed the first helicopter to ever go into mass production. “One of the most dramatic pictures ... in all of aviation history is that of Igor Sikorsky, attired in his usual black suit, fedora jammed on his head, sitting on the strange contraption, hovering above the ground,” The New York Times reported after his death. “The photograph looks unreal, almost as a shot from a Charlie Chaplin movie, but in reality it was the fulfillment of one of mankind’s most enduring dreams: to hover in the air, to go up or down, to fly as a bird flies.”
That man, “universally accepted as the father of the helicopter,” is the author of the helicopter entry in the The World Book Encyclopedia 1964 edition. “With all that,” The Times noted, “he had remained a gentle person, with formal Old World manners, an abiding faith in a power greater than the sky he had conquered—he once wrote a little book on what the Lord's Prayer meant to him—and a magnificent lack of pretension.” Add encyclopedia entry to his legacy. The old is better than the new.