The Straight Dope | The Straight Dope | Chicago Reader

News & Politics » The Straight Dope

The Straight Dope

by

Sign up for our newsletters Subscribe

comment

I have never been able to figure out helicopters. The big propeller obviously makes them go up and down, but how do they go backward, forward, and sideways? I happen to know the little propeller in the back is needed to keep the helicopter from spinning like a top due to engine torque, so that can't be it. Any ideas? --L., Chicago

Any ideas? Not to belittle your question, friend, but I've had more trouble figuring out the directions on a cracker box. Helicopters go forward and backward by altering the pitch of the main rotor blades, i.e., the angle at which the blades meet the wind. Up to a point, the steeper the pitch, the more lift, as you know if you've ever stuck your hand out the window while driving and waved it in the airstream. The trick is to alter pitch unevenly, so you get more lift in, say, the back of the helicopter than in the front. This is accomplished with the system of rods and levers you see near the rotor hub. To go forward, the rods increase pitch (and thus lift) when the rotor blades are in back of the helicopter and decrease it when they swing round to the front. This causes the helicopter to tilt forward and the rotor proceeds to pull it ahead.

A helicopter can be tilted in any direction. To turn, though, what usually happens is the pilot increases the pitch (and hence the thrust) of the small vertical propeller in back. This swings the helicopter around in the desired direction, whereupon we proceed as above. Easy when you know how.

Years ago the media had a big hype about the discovery of the Dead Sea scrolls. Since then, nothing. Were the scrolls translated? What, if anything, was discovered? Or is this another dry hole like the shroud of Turin? --A. Barnes, Towson, Maryland

You, sir, are an ignoble calumniator. (Pretty snappy, eh? Got it from Twain.) What do you mean, "Since then, nothing"? Library shelves groan with books on the Dead Sea scrolls. What you mean is you haven't seen anything in 72-point type on the front page of your local newspaper about them. Although the scrolls have been described as the most important find in the history of archaeology, nothing in them could be described properly as sensational (although see below). They did shed a good deal of light on the origins of Christian beliefs and rituals and fleshed out our knowledge of pre-Christian Jewish life. However, since the average American's interest in the origins of Christianity and pre-Christian Jewish life is pretty much zero, the media didn't pick up on it. In fairness it should also be said that translations and analyses of the scrolls dribbled out so slowly that their impact was minimal.

The first scrolls were discovered in a cave near the Dead Sea in 1947 and many more were found later. Most experts believe they were the library of a monastery of Essenes, an ascetic Jewish sect, that was hidden shortly before the Romans swept through and destroyed everything in 68 AD. The scrolls contain copies of major chunks of the Old Testament (although nothing of the New) that predate previous manuscripts by a thousand years. There are also quasi-biblical texts and religious works, an Essene rule book, and so on.

Considered individually, most of the scrolls are of limited interest to nonspecialists, except perhaps for a copper scroll listing the locations of Jewish treasures presumably hidden from the Romans. (The directions are so cryptic and the sites have been so altered, however, that so far as I know no treasure has been recovered, if in fact it even exists.) Collectively, the scrolls suggest Jesus's ideas weren't entirely original but rather were partly rooted in the beliefs of the Essenes--a shocking notion at one time, but less so today.

Headline-wise, though, the scrolls haven't been a total bust. Renegade scholar J.M. Allegro has claimed they show that Jesus, Mary, and Joseph never existed, and that Christianity is the offshoot of a gang of sex-crazed Jewish drug addicts, which certainly puts a different light on things. Other researchers think Allegro is nuts, but the British tabloids didn't allow this to discourage them and covered the story thoroughly. The U.S. press, on the other hand, generally ignored it, the wimps. Where's Geraldo Rivera when we need him?

Art accompanying story in printed newspaper (not available in this archive): illustration/Slug Signorino.

Add a comment