It was supposed to be a routine mission for U.S. Air Force Lt. Col. Darrell P. Zelko, a veteran pilot of the 1991 Gulf War. The weather over the capital city of Serbia was stormy on the night of March 27th, 1999, and only a few NATO planes were in the sky to enforce Operation Allied Force. Zelco was to drop 2 laser guided munitions and get back to his base in Italy.
There was no way for him to know that at exactly 8:15pm local time, a young Colonel of the Army of Yugoslavia had done what was thought to be impossible. His men had seen Zelco’s unseeable F117 Stealth Fighter.
Seconds later, a barrage of Soviet 60’s era S-125 surface-to-air missiles were screaming toward him at three times the speed of sound. One hit. Colonel Zelco was forced to eject while his advanced stealth aircraft fell to the ground in a ball of fire. It was the first and only time an F117 had been shot down. He would be rescued a few hours later.
How did they do it? How could a relatively unsophisticated army using outdated soviet technology take down one of the most advanced war planes in the world? A plane that was supposed be invisible to enemy radar? As you can imagine, there are several theories. We’re going deep with the “what-ifs” on this one so join us after the break as we break down and explore them in detail.
Continue reading “Ask Hackaday: How Did They Shoot Down a Stealth Aircraft?”
Lift. For a sailplane pilot it means the difference between a nice relaxing flight, or searching for an open area to land. Finding lift isn’t always easy though. This is especially true when the sailplane is hundreds of meters above a pilot whose feet are planted firmly on the ground. That’s why [Tharkun] created PropVario. PropVario is a combination variometer and altimeter for Radio Controlled sailplanes. We’ve seen a few variometers in the past, most often for full-scale sailplane or hang glider pilots. Almost every full-scale plane has a variometer as part of its suite of gauges – usually called a rate of climb or vertical speed indicator.
R/C pilots don’t have the luxury of looking at a gauge while flying though. At altitude even large 2 meter gliders can appear to the naked eye as no more than a dot. It would be somewhat embarrassing to lose sight of your glider because you were checking gauges. The solution is actually simple. A varying audio tone indicates the rate of climb of the plane. Higher pitched tones mean the plane is going up. Lower pitched tones mean the plane is descending. This system, coupled with a simple radio transmitter, has been in use by R/C sailplane pilots for years.
Continue reading “PropVario, a Talking Variometer/Altimeter for RC Sailplanes”