This is why some fighter jets have wavy lines on the canopy – Jalopnik

There is no platform that better demonstrates cutting-edge technology than the modern fighter jet. The F-22 Raptor gave America a super-maneuverable stealth fighter, raising the bar so high that its dominance curtailed its production. The F-35 Lightning would follow with its three variants serving different roles in militaries and countries around the world while rewriting the playbook of modern air combat.

These aircraft are a perfect visualization of how far the fighter aircraft has evolved over the past century. But in addition to the never-ending search for new ways to improve combat capabilities, there is the ongoing technical battle to protect the pilot.

Which brings us to an overlooked design feature baked into fourth- and fifth-generation aircraft today. Take a close look at the canopy of an AV-8B Harrier, F-35 or T-45 Goshawk, and you might notice some strange-looking lines in the glass. These waves are not a visual marker, but are actually detonation cords. As bizarre as it may seem to have explosives inches from pilots’ heads, they could be critical to their lives as these cords play a key role in their safe ejection.

When you shoot out of a fighter jet, you have two options to pull off the great escape. The first, most common method is to simply throw the canopy overboard. This can be done using explosive bolts or even small rockets mounted in the canopy, causing it to fly away when the ejection lever is pulled.

The second is the use of zigzags, known as a Canopy Severance System (CSS). The layout consists of explosive cords embedded in the glass directly above the crew members. When pulled, these cords explode, shattering the glass and punching a hole in the canopy for the pilot to shoot through.

So why continue with the twists and turns to separate just the canopy? Safety. Early ejection systems required a certain altitude and speed to allow the canopy enough airflow and time for the pilot to eject safely. For aircraft like the Harrier and the F-35B, which can take off and land vertically, it is not easy to design a drop system without catapulting the pilot directly into the canopy, with catastrophic consequences.

As we saw with an F-15 a few months ago, modern canopy jettison systems can operate even stationary and on the ground, allowing pilots to eject as little as four-tenths of a second after pulling the lever. However, these systems still eat up valuable time for the canopy to clear the aircraft before the pilot ejects, giving the CSS a significant advantage. DRDO Laboratories has implemented a CSS in HAL Tejas light combat aircraft that promises to reduce ejection time by 95% to one-fiftieth of a second. So the canopy’s bizarre appearance could be the split second that saves a pilot’s life.