Science: Radio Test Pilot

Test pilots, who put experimental planes through their paces, face a potent rival. Airplanes are being tested by remote control with no pilot on board.

Last week the Navy described its version of the gadget that is stealing the test pilot’s job. The cockpit of the plane to be tested is crammed with instruments and radio equipment. Part of the gear controls the plane engine, flight controls, landing gear, etc., by radio signals. The rest, by radio and television, reports the plane’s performance in the air, and does it more completely than any pilot could.

The plane controls are basically the same as those by which the Army flew two pilotless and crewless Flying Fortresses from Hawaii to California a fortnight ago. But a “mother” plane is not always needed. In short-range test work all the flying signals can be sent from a truck on an airfield.

While the “drone” circles or dives at the end of its radio leash, a television tube, like an unwinking eye, watches the instrument panel, sends the readings of every dial to the screen in the radio truck. Other instruments send their readings direct on their own radio channels, recording on a moving paper strip such things as the flutter of the plane’s wings, or the changing strain on its surfaces.

Structural Test. During tests of the airplane’s structural strength, the radio equipment especially shines. Designers like to know how much extra strain an airplane will take. Formerly, they sent a human pilot aloft with instructions to test the plane for the most extreme strains it would get in combat or commercial service. Often, especially in spin tests or pullouts from high-speed dives, something broke or failed to work. Even if the pilot parachuted to safety, neither he nor the plane’s smashed instruments could tell the full story of just what happened at the climax.

Now the operators sit at ease, watching the airplane by eye and radar. A signal puts it into a dive or spin. Down it screams. Shock waves buffet its wings, claw at its tail surfaces. If anything cracks, a flashing light on the television screen tells what part has yielded. No life is lost, and every detail of the plane’s experience, up to the final smash if it comes, is accurately recorded.