All about the F-35

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

There’s a common saying around here: We don’t actually make the F-35 – we just make the important parts.

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?

F-35 jet sitting on the tarmac

Pratt & Whitney makes jet aircraft engines for commercial and military planes, including the F-35 Joint Strike Fighter.

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 as well. The armed services of the United Kingdom, Italy, Germany, Netherlands, Australia, Norway, Denmark, Finland, Canada, Israel, Japan, South Korea, Poland and Belgium all fly the fighter or have plans to do so.

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The F-35 engine is practically invisible to radar.

An F-35 pilot can see in any direction at any time.

An F-35 pilot can see in any direction at any time.

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The F-35 can defeat enemy aircraft without ever being detected.

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JPALS allows naval commanders to launch the F-35 in all types of conditions.

The F-35’s engine

F-35 engine being tested at night

A Pratt & Whitney F135 engine performs at high-power engine run during a test at Edwards Air Force Base in California. Experts at Pratt & Whitney, a Raytheon Technologies business, are working with their colleagues across the company to find new and innovative ways to manage heat on fighter jets.

The F-35’s engine is called the F135, and it evolved from another fighter engine called the F119, which powers the F-22 Raptor.

The F135, known as a fifth-generation engine, has several advantages over the previous generation. Specifically, it produces more thrust, it has a higher capacity for thermal management, and it has adaptive controls that make it easier for pilots to focus on their missions. The F135 is also built from advanced materials and has a modular design that allows for efficient and effective maintenance and upgrades. 

The F-35 is still relatively early in its service life, but the U.S. Department of Defense is looking to the future to ensure the fighter keeps pace with advances from near-peer adversaries. That modernization effort, known as Block 4, calls for a series of new weapons and cockpit improvements among other upgrades. All those new capabilities would push the current engine beyond its original specifications, and with that would come higher operating costs. That means a modernized F-35 needs modernized propulsion as well.

To that end, Pratt & Whitney has proposed an upgrade to the existing F135 engine known as the Enhanced Engine Package, or EEP. The business’ military aviation experts point to several key benefits – mainly its cost-effectiveness, its low risk and its capability. 

From an affordability perspective, EEP is what’s known as “variant-common,” an important hallmark of the F-35 program that means it can work on all three variants of the fighter. As such, EEP would use the existing production and sustainment infrastructure, and it would maintain the current cost-share ratios for the U.S. services and partners that operate the fighter. It’s also production-cost neutral, meaning an upgraded F135 off the assembly line would cost the same as the current configuration. All told, Pratt & Whitney estimates EEP would save approximately $40 billion in lifecycle costs.

As for low risk, EEP is a derivative design that builds on an architecture that has already logged more than a million flight hours of safe operation between the F135 and F119. It is weight-neutral and requires minimal airframe integration and testing, and it was designed from the onset to be cut into production and retrofit during engine overhaul, minimizing any disruption to the program of record. 

And in terms of capability, EEP takes advantage of the U.S. Department of Defense’s investments in advanced propulsion technologies to meet or exceed the necessary requirements for Block 4. For all variants, EEP would deliver a boost of more than 10 percent in thrust and range, and a jump of more than 50 percent in thermal management capacity. It also provides a five-percent increase in powered lift to the F-35B, the version that can perform short and vertical takeoffs and landings. 

EEP even has advantages in sustainability; it will reduce carbon dioxide emissions by 43 million tons over the life of the program and, like today’s F135, will be ready to use sustainable aviation fuels.

“With more than a million hours of fifth-generation fighter engine experience, we’re in a unique position to offer a full range of modernization options for the F-35,” said Jen Latka, Pratt & Whitney’s vice president for the F135 program. “With EEP, we’ve incorporated the latest technology to give pilots the capability they need, while still maintaining variant-commonality to maximize affordability.”

The F-35’s weapons

AMRAAM missiles on a plane

Procured by dozens of countries, the combat-proven AMRAAM air-to-air missile has been operational and integrated into the F-35, along with the F-16, F-15, F/A-18, F-22, Typhoon, Gripen, Tornado and Harrier.

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.

An upgrade called F3R, or Form, Fit Function Refresh, will bring even more capability to the missile through increased range and enhanced performance against advanced threats.

“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. 

StormBreaker is the U.S. Air Force’s first network-enabled weapon, meaning control can be transferred after launch to another fighter jet or to ground forces, which can then provide new targeting data in real time. 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 fighter jet 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 data display

Collins Aerospace and Elbit Systems of America

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.

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 head-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 head-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 your 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 strained-layer super-lattice detector material comes from Raytheon Missiles & Defense, which procures 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

Fighter jet taking off from an amphibious assault ship

An F-35-B Lightning II assigned to marine Fighter Attack Squadron (VFMA) 121 takes off from the amphibious assault ship USS Wasp (LHD 1). Photo by Mass Communications Specialist 1st Class Daniel Barker/Released.

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 System, 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 builds 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," Jaynes said. "You go in, you get out.”