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This GE-Powered Stealth Aircraft Still Awes Aviation Enthusiasts 40 Years Later

June 18, 2021 | by Cole Massie
Lacks afterburner. Unstable on all three flight axes without the help of an onboard computer. No curved surfaces. Limited payload.

This eyebrow-raising scouting report probably came as a concern to some pilots. But there’s one more piece of information that erased those concerns: nearly invisible to enemy radar.

Now that’s something.

The jet was the Lockheed Martin F-117A Nighthawk. On this day 40 years ago, under tight government security, it lifted off for the first time from a Nevada dry lakebed—known popularly today as Area 51.

All those less-than-ideal fighter jet features were necessary to fulfill the F-117’s one true requirement—stealth. When the F-117 took off that day in June 1981, it became the first jet in the skies with stealth as its primary feature.

Photo credit: Lockheed Martin

Why stealth?

Cold War conflicts were the first to primarily feature jet-powered fighters. Although the U.S. held a technological edge over its adversaries, contested airspace still posed significant danger to pilots and their aircraft. Advancing enemy technology could lock onto U.S. fighter jets and take them out of the sky at an alarming rate.

U.S. airframers took on the challenge: minimize any characteristics that could give away an aircraft’s location. This meant subsonic flight to cut noisy sonic booms. It meant no afterburners or large exhaust plumes from engines that could emit infrared signatures. It meant flat surfaces that would bounce radar waves away.

The result was an otherworldly-looking black jet that remained unacknowledged by the U.S. government until 1988.

We need an engine

Around the time Lockheed Martin won the contract for the F-117 in 1978, McDonnell Douglas’ F/A-18 Hornet took to the skies for the first time. GE designed the brand-new F404 engine specifically for the Hornet. Reliable, maintainable, lightweight, and affordable, the F404 quickly earned its stripes.

The F404 also became an intriguing option for a top-secret aircraft in need of an engine—the F-117.

Unbeknownst to all but a few employees at GE’s Lynn, Massachusetts, plant, GE built the F404-F1D2 for the F-117. It was almost identical version to the F/A-18’s F404. In a separate assembly line made up of only government-cleared employees, GE built more than 100 of these engines.

A 1970s-era cutaway of the F404 that powered the F/A-18 Hornet, designated the F404-GE-402. The F404-GE-F1D2 had no afterburner. Credit: GE

“It just blew me away”

Bill Formosi, GE’s F404-F1D2 Program Manager from 2000 to 2004, remembers the first time he saw an F-117 in person.

“It’s probably the highlight of my career,” Formosi recalled. “It was out at Holloman Air Force Base in New Mexico. They pulled an F-117 out of a hanger and into a Quonset hut to get it all prepped for flight.

“When they got ready to launch the aircraft, they had us pile into the back of a pickup truck, and they followed the F-117 out as it taxied. People think because of the special exhaust and no afterburner, that it doesn’t have much power—they’d be wrong. The aircraft powered up, and the whole truck was shaking.”

“Even though I came in about 20 years after the aircraft had first flown, the first time I stood next to the F-117, and then being in the truck as one launched… I mean, it just blew me away.”

The -F1D2

Formosi, still with GE as a Materials and Logistics Manager, is one of few remaining GE employees who worked on the F404-F1D2 program.

According to Formosi, there wasn’t anything that unique about the engine.

“That was the beauty of it, really. They were able to take an existing engine that had the necessary thrust and weight and make it work. There were some minor tweaks to accommodate for the specialized inlet on the F-117.”

The F-117’s air intakes, unlike other jets of the time, were grilled and covered in a specialized, radar-absorbent coating. There were also spring-loaded hatches that would open on the ground to get the engine more air. Once in flight, however, the hatches would close back up to preserve the aircraft’s stealth properties.

Photo credit: Lockheed Martin

The truly unique part of the engine, Formosi said, came from the tailpipe.

“If you look at an F-117 from behind, you’ll notice you can’t see the engines like you would in other aircraft,” Formosi explained. “That’s on purpose, and it had everything to do with keeping it stealthy. Rather than an afterburner like the F404 had on the F/A-18, there was a 12-stage tailpipe that went from circular at the end of the engine, to flat at the end of the exhaust.”

“That was done to disperse the hot exhaust air across a greater area, which minimized its heat signature.”

The roughly 15-foot-long tailpipe also required layers of material to absorb engine heat. The excess head could impact radar-absorbent paint covering the outside of the aircraft.

A Republic F-84 Thunderjet with an experimental slotted exhaust nozzle, circa 1958. The same general design principles were applied to the F404-F1D2 tailpipe. (Photo credit: NASA)

An enthusiast’s dream

Many people who work in the aviation are also enthusiasts for the industry. Formosi, no exception to that, had some spare time as he worked from home during the COVID-19 pandemic. He found an F-117 scale model kit that had been collecting dust at his house, which he believes someone gave him back when he was the -F1D2 program manager. Formosi assembled and painted the model, remarking it is still “no doubt” his favorite aircraft ever.

He remembered what a surprise it was when Lynn’s employees found out GE had built the engine for the aircraft. “Nothing philosophical to say. It was really just pride in knowing GE had a hand in it.”

He remembered the bittersweet moment in 2008 when the U.S. Air Force retired the F-117.

And then there’s the cool factor—which still holds up four decades after its first flight.

“It’s just such a cool airplane. The F-117 didn’t, and still doesn’t, look like anything else. It’s wasn’t, and still isn’t, like anything else. I’m just grateful I had a small part in its story.”

Photo credit: Lockheed Martin

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