What’s A Maser?

Reading “Amazing Light” (by Joan Lisa Bromberg) in the Spring 1992 issue, I was reminded of a seminar I attended in about 1964 for MIT graduates. Charles Townes spoke and described the development of the maser. However, instead of using the usual technical definition—Microwave Amplification by Stimulated Emission of Radiation—he advised us of a more practical definition: Method for Arriving at Support for Expensive Research.

Thanks for an elegant article in a thoroughly attractive magazine.

John R. M. Alger
Rumney, N.H.

What’s A Maser?

As always, your latest issue was full of interesting articles. I was a graduate student and then a research fellow at Caltech at the time of the development of the maser. I always understood the acronym to stand for Money Acquisition Scheme for Expensive Research.

George T. Skinner
Tullahoma, Tenn.

Wheel Trouble

Thank you for the fine article “The Bicycle Story” (by David V. Herlihy) in your Spring 1992 issue. I would like to add some comments based on personal experience. The “high-wheeler” was easy to ride on a flat surface but required a lot of muscle to climb even gentle hills, whereas going downhill was frequently terrifying. You had to stand up and push back on the pedals to control your speed, but eventually you were overcome by gravity; the pedals and your feet parted company, and you were left with no control whatsoever. The only solution was to hang on grimly, legs akimbo, and pray that a horse and cart would not appear at the bottom of the hill. I ran into teams of horses on two occasions, and one of the animals had the audacity to bite my arm.

This was solved around the turn of the century by the invention of the free-wheeling mechanism. This invention, together with the caliper brake, pneumatic tires, and now multigear changing devices, has resulted in cycling’s remaining a very popular sport and the preferred means of locomotion in many parts of the world.

During World War II in Germany, bicycle tires were made of hundreds of metal washers threaded on a stout cable around the wheel rim. That was a boneshaker indeed.

Ray D. Manners
Arlington, Va.

Pioneering In Unmanned Flight

Your article about fly-by-wire, “The Airplane as Computer Peripheral” (by James E. Tomayko, Winter 1992), reminds me that as early as 1943 I was a project engineer closely involved in the development, installation, and use of such a system.

At the time, I was working at the Junkers Aircraft Company in Germany. I was assigned to the Mistel Project, preparing a piggyback combination of a Messerschmitt Me. 109 or FockeWuIf Fw. 190 fighter atop an unmanned Junkers 88 bomber. The contraption was flown by the fighter pilot; the bomber was fitted with a six-foot hollow charge replacing its cockpit. The fighter would separate from the bomber at a safe distance from the target.

There were no mechanical flightcontrol connections between fighter and bomber; the control system was a true fly-by-wire system, its heart a gyro-controlled three-axis autopilot. The modifications for each axis consisted of potentiometers attached to the respective control surfaces wired as a bridge and thus providing inputs to the autopilot, which also provided damping inputs. By adjusting the gain of the feedback loop and the damping inputs, any desired flight qualities and feel for the single pilot could be achieved. The system was completely developed in 1943, and during 1944 and early 1945 more than a hundred units were built.

Fritz Haber
Westport, Conn.

Pioneering In Unmanned Flight

I was dismayed to find not one but two technical errors in “The Airplane as Computer Peripheral.” The reference on page 21 to the B-58 and the SST having “computers hinge the wings” leaves me dumfounded. Neither aircraft has pivotable wings. And a picture caption on page 22 refers to the space shuttle Enterprise “perched atop the plane it launches from.” The space shuttles are all launched vertically from rocket pads.

Leonard Levin
Castro Valley, Calif.

The editors reply: An error in editing changed what should have read “computers hinge the wings’ control surfaces.” And that caption should have used the past tense. The Enterprise did launch in mid-air from its 747 carrier in flight tests.

Editor’s note: Frederic D. Schwarz, the managing editor of Invention & Technology , has managed to compile a ninety-page index to the magazine, covering Volume 1, Number 1, through Volume 7, Number 2—that is, Summer 1985 through Fall 1991. We can make it available (in soft covers) to interested readers for ten dollars a copy prepaid. Send orders to: Index, American Heritage of Invention & Technology, 60 Fifth Avenue, New York, NY 10011.