Development of the Constellation

ATC Observer, Volume 3, Issue 8, 2 March 1945, Page 13

Development of the Constellation

By

(Concluded) 0F the large amount of time and money spent on the Constellation, a great proportion was devoted to the conquest of one of the biggest bugbears in the high speed aircraft—flutter. Many pilots of racing planes in the 1920’s were killed when their machines, diving for the finishing line, suddenly went out of control or even broke up in the air. For many years test pilots and research engineers cooperated to discover the source of this trouble and found that as the airspeed increased, the control surfaces acted normally at first and then suddenly started to vibrate alarmingly—much as a leaf does in the wind. So great was the force of this flutter, that the pilot was unable to prevent it. Terrific strains were imposed on the structure and the lack of a steady airflow meant that control of the aircraft was lost. The present methods of preventing flutter are known as mass and aerodynamic balancing. These, however, are by no means 100% effective and

are useful to a small extent only. The former method necessitates the addition of weight, while to use the latter, the designer must sacrifice some of the efficiency of the control surface itself. Lockheed spent 5 years on their answer to this problem—“booster” control. Incidentally it overcomes another problem as well, as it relieves the pilot of the full responsibility of controlling a machine about one hundred times as heavy as himself. The system is similar to that used to work the steering gear on ships, but is, of course, much more sensitive. By an extremely clever method, movement of the pilot’s control column and ruddur bar actuates a hydraulic system, which, in turn, moves the control surfaces, which are thus held rigid by the hydraulic jacks and have less tendency to flutter. Both the pilot and the plane are thus relieved of a great amount of the strain.

Thus we see that hours of patient research and development are necessary before the Constellation and machines like it are ready to link the nations of a world at peace.