Electronics Assembly Knowledge, Vision & Wisdom
Eavesdropping on the Enemy
Eavesdropping on the Enemy
The military wanted to listen to the enemy from overhead. What type of aircraft would be quiet enough to make listening possible?
Mysteries of Science
Dr. Gilleo
Mysteries of Science by Dr. Ken Gilleo
Dr. Gilleo is a chemist, inventor and general problem solver. Ken has been tracking industrial forensics and collecting case histories for decades. These cases are taken from the vast world of industry and commercial enterprise.

Check out Dr. Gilleo's eBook, 100 Mysteries Solved by Science. We hope you enjoy these case histories. You need not be an engineer or scientist to understand the problems and appreciate the solutions.
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The Vietnam War was in full swing and things were not going well. The Vietcong kept getting supplies through at night when it was relatively cool and hard to see even with night vision.

Military planners kept thinking about detection and hit on a simple idea. Listen for enemy noise, and plot the location for bombers.

But what aircraft could be used that wouldn't make so much noise that it would make listening impossible?

The answer was a balloon and a plan was hatched.

The lifting power would come from a helium filled balloon and controlled by motor driven propellers. The listening devices would be microphones on long trailing wires.

To camouflage the balloon everything would be dull black.

The balloon and engine were shipped to South Vietnam where a General insisted that the balloon be launched so he could be sure it worked. One of the techs began explaining why that was not a good idea, but the General boomed, "Get that thing up right now and don't say another word."

The balloon was launched under the hot afternoon Vietnam sun and performed well. It came gliding by the group with the microphones hanging about 10 ft. off the ground and every mumble and grumble was transmitted back to the radio room. On the second pass, the microphones were 100 ft above the ground. The flight crew had the rudders set for a dive, but the balloon kept on rising.

What was going on?

Here's the rest of the story.

The black balloon was absorbing the sun's heat and the heat was expanding the helium. Finally the balloon had too much lift to fly level.

In the 100-degree sunlight, the balloon was going to stay up for a long time. "Get it down or I'll shoot it", yelled the General.

Finally, the balloon was brought down and destroyed by a squadron of US jets.

The secret balloon had done just what was expected and no one but the General was surprised. Maybe there's no lesson, but there is a message. No matter how important you are, listen to the experts.

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