All about the F-35

Raytheon Technologies makes much of what goes in and on the futuristic fighter jet

Of course, that’s an exaggeration. The airframe, for example, is obviously pretty important to the F-35’s ability to fly undetected by enemy radar, and we don’t make that. And there is a vast network of companies that make many of the plane’s systems, subsystems and parts. But there’s some truth in the statement too: Every time the F-35 does something, there’s a good chance a Raytheon Technologies product played a part.

Pratt & Whitney builds its engine. Collins Aerospace makes the visor that shows pilots what’s happening in the skies around them. Raytheon Missiles & Defense makes the precision weapons it uses for air-to-air combat and air-to-ground strikes. And Raytheon Intelligence & Space makes a navigation system that helps it land on aircraft carriers and austere airfields.

What does the F-35 do?

Before we get into the parts, let’s talk about the plane. It has an enormous job to do. The U.S. military is counting on the F-35 to replace several fighters including the Air Force’s F-16s, the Navy’s and Marine Corps’ F/A-18s, the Marines’ AV-8B Harriers and the UK Harrier GR7s and Sea Harriers. That means it has to excel at air-to-air combat, carry out air-to-ground precision strikes in all weather, fly stealthily into contested areas, have unsurpassed “situational awareness,” or data on what’s going on around it, and land basically wherever the military needs it to land. And it needs to be “survivable,” a military term meaning it can either avoid or withstand attack.

“The Air Force is really buying it to be the workhorse of its fighter community. The Navy is doing the same,” said retired U.S. Air Force Maj. Gen. Jon Norman, who leads Air Power Requirements and Capabilities for Raytheon Missiles & Defense.

The U.S. expects to fly the F-35 well into the 21st century, and other nations have placed their bets on it too: the armed services of the United Kingdom, Italy, Netherlands, Australia, Norway, Denmark, Canada, Israel, Japan, South Korea, Poland and Belgium all fly the fighter or have plans to do so.

The F-35’s engine

The F-35’s engine is called the F135, and it evolved from another engine called the F119. One key difference: The F135 was specifically designed for a single-engine fighter, while the F119 was built for a twin-engine aircraft – the F-22 Raptor. That means the F135 has built-in safety features, such as redundancies in hardware and software, allowing it to reconfigure itself in flight upon detection of a failure.

“If you were in a twin-engine application, you would just shut down that one engine and fly home on the other,” said Mark Aubuchon, a recently retired chief engineer at Pratt & Whitney. “We don’t have that luxury. If there’s a problem, other aspects of the overall control system take over and keep the engine running safely.”

Another feature of the F135: One version provides short take-off and vertical landing capability, so that the F-35B variant flown by the U.S. Marine Corps and several international customers can operate from austere bases and a range of ships. That requires some special modifications – namely the Rolls-Royce-produced LiftSystem, which consists of a lift fan, driveshaft, roll posts, and 3 Bearing Swivel Module that allow the nozzle to tilt down 90 degrees – along with an adaptive control system that enables the aircraft to switch between hover and conventional flight at the push of a button. For engineers, pulling that off has been a feat, but for pilots, Aubuchon said, it’s “an effortless activity.”

“They just command it to go up or down, and it does,” he said.

The team that built the F135 also had to overcome an interesting engineering challenge: Designing an engine that was practically invisible to radar. Engines contribute to a plane’s radar signature, making it easier for adversaries to detect and identify. With the right geometry and stealth technologies such as special coatings, however, the Pratt & Whitney team pulled it off.

“We’re part of the signature, particularly on the back end of the aircraft, so our stealth capability is very important,” Aubuchon said. “We do everything we can to make our engine as invisible as possible.”

The F-35’s weapons

One main part of the F-35’s mission is to conduct operations in hostile territory, or what military officials call “an anti-access airspace denial environment,” and survive whatever surface-to-air missiles or air-to-air missiles might await it. That requires stealth – the F-35 even carries its weapons internally to preserve its stealth advantage – and the ability to defeat adversaries beyond visual range. And that’s where the AMRAAM missile comes in.

A pilot flying an AMRAAM-equipped F-35 can detect, target and engage enemy aircraft at distances well beyond visual range. The missile has a semi-active radar that allows pilots to engage enemy aircraft at extreme ranges and get away before they are threatened – an advantage known as “launch and leave capability.” That, coupled with the plane’s stealthy features and advanced sensor suite, means the F-35 can defeat enemy aircraft without ever being detected.

“The F-35 paired with the AMRAAM preserves our first-launch opportunity against advanced threats,” Norman said. “Before they even have a track on our aircraft, our F-35 pilots are able to engage an adversary with AMRAAM and leave. This is the exact advantage our pilots need in combat and the exact capability the AMRAAM delivers.”

Another of the F-35’s missiles is the Raytheon AIM-9X Sidewinder, a shorter-range air-to-air missile that uses infrared instead of radar to detect, track and guide to a target. That helps the plane stay stealthy; fighter jets typically can sense when they’re being targeted by radar, and when they do, they alert their pilots. But with infrared targeting, there’s no such warning.

“As a fighter, if I can passively track and target and not give an adversary warning I’m there, and still employ ordnance, then I have a significant offensive advantage,” said Norman, a former F-16 pilot.

As for ground strikes, the F-35 will carry the StormBreaker smart weapon, a gliding munition with a seeker that works three different ways – millimeter-wave, which allows it to find targets in darkness and in any weather; infrared, which helps discriminate between targets, and semi-active laser, meaning it will follow the direction of a laser designator operated either from the air or on the ground. It also has greater range than older munitions – about 40 miles – meaning an F-35 can zoom out, take a wide field of view and engage several targets at the same time. The plane also carries the Paveway laser-guided bomb, an air-to-ground precision guided munition that fulfills another of the F-35’s missions: close air support for ground forces.

One other key to the F-35’s strike capability: sometimes, it doesn’t even launch anything. The plane’s suite of radar, sensors and targeting systems essentially make it a flying sensor and battle manager, and it has even shown in tests that it can provide targeting data and guide a ground-launched missile against threats over the horizon.

The F-35’s heads-up display

One big difference between the F-35 and the planes it’s replacing is the way pilots see data from radars, targeting systems and other sensors.

Historically, fighter jets have used a heads-up display – a clear piece of glass atop the instrument panel with a projector that overlays information about whatever is in front of it. With that, pilots can tell all kinds of things about their mission, including where the nose of the plane is pointing, how far away a target or waypoint is and which weapons are available.

With the F-35, the heads-up display is integrated into the visor of the pilot’s helmet. The information is no longer available in only one place; it moves with the pilot’s gaze.

“You have it right there in front of you, regardless of where you’re looking – out the window, over our shoulder, down – you’re looking through the aircraft, so to speak,” said Bret Tinkey, who manages helmet programs at Collins Aerospace. “It’s all in front of you, all the time.”

Feeding into that display is one of the F-35’s most important and most revolutionary features: the network of sensors spread out across its airframe. Those sensors, called the Electro-Optical Distributed Aperture System, allow an F-35 pilot to see in any direction at any time – a major improvement over the fixed sensors on older fighters.

“The way it’s been classically, you’re frequently maneuvering your jet to receive full defensive threat coverage. Or you have a formation and one of you concentrates on one sector, while the other aircraft concentrates on another,” said Russ “Rudder” Smith, a retired U.S. Air Force colonel who now leads business development for tactical electro-optical and infrared systems at Raytheon Intelligence & Space. “With 360-degree awareness, it obviates the need for maneuvering your aircraft or formation to see the entire operating picture. You can do it all through one system.”

The sensors use two key components from across Raytheon Technologies: the super-strained lattice detector material comes from Raytheon Missiles & Defense, which manufactures it for use in ground radars, and the focal plane arrays come from Raytheon Vision Systems in Goleta, California. Those advancements, coupled with digital pixel technology and a digital read-out integrated circuit, give pilots a quick, high-definition picture of everything around them, Smith said – “in short, a more capable missile detection system.”

The F-35’s landing system

Let’s go back to one of the F-35’s most important requirements: The military needs it to be a “low-observable” aircraft, meaning it has to be very hard for adversaries to detect. Doing that in flight is one thing, but when you’re talking about landing it in contested territory, it’s even harder. Aircraft typically rely upon surface radars and legacy instrument landing systems when they’re required to penetrate weather for landing. The radars and instrument landing systems emit energy that adversaries can detect, which puts aircraft and landing locations at risk.

So what do you do in that case? You use a secure encrypted data link instead. That’s the job of the Joint Precision Approach and Landing Systems, also known as JPALS. It goes on all three variants of the F-35, giving them a way to land on ships at sea, as well as temporary airfields in remote locations, in just about any weather. Raytheon Intelligence & Space built and manages the ground stations.

With JPALS, naval commanders can launch aircraft in all kinds of conditions, knowing they’ll be able to return and land once the mission is over. It also saves fuel, preventing pilots from having to loiter and refuel until landing conditions are more favorable.

“It gives them options, and it gives the pilot a sense of security, knowing they’re coming back home,” said retired U.S. Navy Rear Adm. CJ Jaynes, who now works at Raytheon Intelligence & Space as an executive technical advisor.

On land, JPALS basically gives ground forces an instant airport – it can be set up quickly and in the most austere locations, which opens up all kinds of tactical options.

“Think about special ops. You go in, you get out,” Jaynes said. “Think about a mission like Osama bin Laden. If we would have had JPALS, maybe we would have gotten him sooner and weather would not have played a role in the timing.”

F-35, helmet mounted display and heads up display
These helmet-mounted displays, made through a joint venture between Collins Aerospace and Elbit Systems of America, help F-35 pilots understand the airspace around them.
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