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  • This episode of Real Engineering is brought to you by curiosity stream. Watch thousands

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  • This year the F-35 is finally set to close it’s 27 year development phase, and move

  • towards high volume manufacturing. The culmination of 27 years of design and development from

  • its manufacturer, Lockheed Martin. 27 years of development, crossing the finish line in

  • the midst of a political power struggle in America. This is after all, the most expensive

  • weapons system in the history of humankind.

  • Costs have inflated as a result of the America military-industrial complex, where the intertwining

  • of politics, economy and the military industry encourages companies like Lockheed Martin

  • and Boeing to not vertically integrate their companies, as a means of spreading jobs across

  • America and thereby increase political support for these programs and the politicians that

  • approve them in congress to win contracts. We could deep dive into these muddied waters

  • of politics, but this channel is about engineering and the development costs of the F-35 would

  • be astronomical even without these issues, so let’s explore the design of this plane

  • and see whether it’s price tag is really worth it.

  • From the start, the F-35 sought to be the jack of all trades. [1] An air superiority

  • machine to replace the Air Force’s F-16s and A-10s. A stealth fighter, taking the lessons

  • learned from the B-2 program and improving upon Lockheed’s previous ventures into stealth

  • technology, with the F-22 Raptor and the F-117 Nighthawk. A carrier capable fighter to replace

  • the F/A-18 Hornets of the Navy, and perhaps most audacious of all, it would take on the

  • challenge of vertical landings, taking over from the British AV-8B Harrier.

  • Taking on all these advanced technologies and combining them into one plane was never

  • going to be an easy, or cheap task, and the program was made even more expensive by what

  • was initially intended to be a cost saving measure.

  • This plane would be developed as a joint venture between 3 US Military branches. The Air Force,

  • Navy and Marines. A single plane for each branch of the military. The program was named

  • the Joint Strike Fighter, and it’s goal was to produce a next generation plane that

  • could replace fighter, strike and ground attack aircraft of not just the United States, but

  • all of its Allies. Unlike the F-22 Raptor, which is an US Air Force exclusive plane,

  • the F-35 would be commercially available.

  • The JSF program began life as a competition, between McDonnell Douglas, Northrop Grumman,

  • Lockheed Martin and Boeing. With Lockheed and Boeing going on to develop prototype aircraft

  • as finalists in this competition, both eager to win what was sure to be one of the most

  • lucrative contracts they would ever sign. Boeing’s aircraft, the X-32, was an odd

  • looking aircraft. Featuring a massive single air intake that made it less VTOL and more

  • VLOL. [2]Its looks alone may have stopped it from winning this valuable contract, but

  • what really held it back was Boeing’s decision to create two prototype planes. One capable

  • of supersonic flight, and one capable of vertical take-off, [3] using the same vectored thrust

  • as the Harrier, which it was supposed to be replacing.

  • The engine used in the Harrier is similar to a traditional jet engine in that it consists

  • of a low pressure compressor fan, a high pressure compressor, a combustion chamber, a high pressure

  • turbine and a low pressure turbine.

  • But it’s outlet nozzle placement is anything but traditional. 2 outlets are placed immediately

  • after the low pressure compressor, with another two ducting air from the higher pressure turbines.

  • In vertical thrust mode, the nozzles point downwards, and allow the plane to balance

  • precariously on these 4 columns of air.

  • The Harrier was not an easy plane to control in this flight mode and on more than one occasion

  • turbulence from it’s own downwash caused the plane to flip over onto the cockpit during

  • landings, killing the pilot. [4]

  • A large part of these control issues can be attributed to the proximity of the control

  • nozzles to the centre of gravity of the plane. Giving them less mechanical advantage to manipulate

  • the planes attitude. The Harrier did have small roll control nozzles on the tip of each

  • wing, but the control for these were entirely manual. Placing the incredibly unstable control

  • mechanism into the hands of a human that needed to focus on various other factors when landing.

  • The X-32 used many of the same techniques to achieve vertical thrust, but improved on

  • many of the Harriers short comings. Instead of using the same nozzles for cruise and direct

  • lift, the X-32 would close valves for each when needed. In normal flight the cruise nozzles

  • would open, allowing the thrust of the jet engine to be directed efficiently through

  • the rear of the aircraft. Then, during transition, this nozzle would close and force air through

  • the direct lift nozzles.

  • They placed larger roll control nozzles further from the planes centre of mass and also employed

  • a cold air screen placed just forward of the lift nozzles. [5] This was intended to stop

  • hot turbulent air from the direct lift nozzles from entering the front intake, which was

  • a massive issue for the Harrier as it landed. Jet engines need cold and smooth air to operate

  • at maximum thrust, which was difficult to get when landing and directing the entirety

  • of your thrust directly at the ground.

  • Despite these improvements, Lockheed ultimately won the contract. Impressing the JSF program

  • with their lift fan system. The engine thrust here, once again, exits a single exhaust nozzle

  • during normal flight, but when the show begins, the X-35 was capable of some incredible transformer-like

  • changes.

  • Hatches opened on the top and bottom of the aircraft, revealing two contra -rotating fans.

  • Another 2 little doors open beneath the wings, exposing two additional exhaust ports that

  • control the planes roll. Finally, as the plane begins to slow down, the cruise nozzle will

  • begin to pivot downwards, transitioning the remaining thrust of the jet engine from horizontal

  • to vertical. [6] The lift fan solved many of the same issues that plagued the harrier.

  • The lift fan produced the majority of the vertical thrust and it did not heat up the

  • air significantly in the process. The roll control had significantly more mechanical

  • advantage and divvied the majority of the control over to a computer.

  • Perhaps most influential in their success to winning the contract, this prototype was

  • capable of both vertical landings and supersonic flight. This was the kind of innovation the

  • Joint Strike Fighter program was looking for.

  • The lift fan is essentially a turboprop engine like something you would find on an Osprey.

  • The propellers are driven by a drive shaft connected to the jet engine turbines, which

  • can be disengaged during normal flight. This means the lift fan is deadweight during cruise,

  • but what it adds in weight, it more than makes up for in lift.

  • Combined these propulsion methods can produce 185 kilo Newtons of lift. [7] The Harrier

  • could only manage 106 kN [8]. This increase in direct lift capabilities was vital to making

  • the F-35 a worthy successor to the Harrier, as one of the Harriers greatest weaknesses

  • was its limitations in maximum take-off and landing weight.

  • The Harrier, like the F-35B, mostly operated in short take off and vertical mode. The Harrier

  • would point all four of its nozzles at about a 45 degree angle, allowing it to produce

  • both horizontal and vertical thrust to take off from shorter runways. This allowed it

  • to take off with considerably more weight than it could land with a vertical landing.

  • The empty weight of the F-35b may be 13,154 kilogram [9], compared to the 6,340 kilograms

  • of the Harrier [10]. But it more than makes up for that with a maximum take-off weight

  • of 31,800 kilograms compared the Harrier’s 14,100 kilograms. That’s an extra 11 tonnes

  • of weight available to the F-35 for fuel and ammunitions. Something the Harrier had little

  • space for. So, the F-35 is more than a worthy successor to the Harrier. A plane which fetched

  • about 24 million dollars per unit in 1996, or about 39 million adjusted for inflation.

  • [10]

  • So, incorporating VTOL to the F-35B was just one of many design challenges that pushed

  • the price of the program up. Ironically, despite Boeing's duel prototype entry being a sticking

  • point for the JSF program. The F-35 now comes in three variants. [11]

  • Each tailored for different branches in the US military. The F-35A is customised for the

  • US Air Force, and as such has been designed to take off from conventional runways. Allowing

  • it to scrap much of the heavy equipment needed for the F-35B, the Marine’s variant.

  • The Marines do not operate out of large aircraft carriers, like the Navy, and as such their

  • ships, like the Wasp-class amphibious assault ship, have been often referred to as helicopter

  • carriers. As no plane, other than a Harrier or Osprey, have been able to use them. This

  • is not the case for the Navy, who have large aircraft carriers at their disposal.

  • The final variant is the F-35C, which has been designed to satisfy the Navy’s requirements,

  • having wings that are about 40% larger than either of it’s sister variants and it’s

  • landing gear is much heavier and . Both these features were included to allow it to land

  • and take off from aircraft carriers, without the need for the vertical propulsion of the

  • F-35B. The larger wings not only allow the F-35C to have the largest fuel capacity of

  • the 3, but also give it much better lift at slower speeds. Making landings and takeoffs

  • much easier on the deck of an aircraft carrier, while the heavier landing gear allows the

  • plane to survive the rough landings associated with the arresting wire landings on aircraft

  • carriers. The F-35C also incorporates folding wing tips to allow for neat storage inside

  • the ship.

  • This expansion into 3 variants has been a huge source of increased costs, and the program

  • likely could have dramatically reduced on spending had it just designed three different

  • planes for the 3 different branches. Trying to squeeze the needs of these 3 military branches

  • into a single airframe was never going to be an easy task for the R&D division of Lockheed

  • Martin, and forced them to make some concessions in design that have limited it in other areas.

  • The brunt of the criticism directed at the F-35 is its shortcomings in its dog fighting

  • capabilities. Headlines of the F-35 losing simulated dog fights to the cold war era F-15s

  • and F-16s grabbed many people’s attention, and were used to detract from the F-35s advancements.

  • [12]

  • We only knew about these issues as a result of report that leaked to the press. Let’s

  • take a look at that report [13] to see what this test pilot thought about the F-35A he

  • flew.

  • The primary flaw this pilot highlight was the F-35As poor energy maneuverability. Meaning

  • the F-35A struggled to maneuver without expending a significant amount of its kinetic energy,

  • which is a problem I discussed in more detail in my fighter jet instability video. The primary

  • design aspect the pilot pins this on is the smaller wing area and weaker afterburner thrust

  • of the F-35 in comparison to the F-15E he was accustomed to. Essentially their issue

  • with the F-35 was that it depleted it’s kinetic energy store quicker than it’s competition.

  • We have no reason to believe this pilot was wrong in his findings, so what does this mean

  • for the F-35? It is important to note that this was not a fully functional version, missing

  • software enabling the plane to detect it’s foes before they can detect it and was missing

  • it’s radar absorbing paint. [14]

  • On top of this, the F-35 is not short of trained military aviators who praise the F-35. [15]

  • Like US Marine Corps Major Dan Flatey, who helped design the combat training program

  • for F-35 pilots, and he has chalked up these issues to old habits of pilots who have spent

  • significant portions of their lives dedicated to older generation planes, which were designed

  • with a different philosophy. Since then the F-35 has performed phenomenally in simulation

  • with reports up to 20-1 kdrs. [16]

  • Other pilots, who have had more time to become accustomed to the F-35 had more positive things

  • to say. Like Jon Beesley, the chief test pilot of the F-35, with 22 years of experience as

  • a test pilot at Lockheed Martin and was involved in the development of the F-117 Nighthawk

  • and the F-22 Raptor. He claims that the F-35 can out maneuver any

  • US fighter except for the F-22, which was designed specifically as an air superiority

  • machine and AGAIN is not available for purchase outside of America and actually has a higher

  • unit cost than the F-35 at about 150 million dollars. It’s hard for me to make a judgement

  • call on this because I have as little information as any other civilian, but honestly, outside

  • of this one report most pilots who have flown with the F-35 sing its praises.

  • Jon Beesley also makes an important note. Air Combat has always relied on stealth, whether

  • it was world war 1 pilots diving with the Sun at their backs or modern fighters using

  • advanced radar masking design.

  • Because, in the grand scheme of things. In a dogfight the real stat that matters is who

  • sees and shoots first, and the biggest factor that contributes to that today are on board

  • sensors and stealth.

  • The thing that really sets the F-35 apart is it’s suite of sensors and computer guidance

  • systems, which have been integrated with the user interface of the aircraft unlike any

  • other plane in history of mankind, while sharing that information with the entire force. This

  • is what truly makes this plane something to be feared, and it all starts with this. A

  • little transparent faceted sensor suite [17], containing the infrared imaging and tracking

  • equipment of the aircraft, but those are not your typical windows. Those are made of sapphire,

  • a notoriously expensive gemstone. One of the few materials that is both hard and durable,

  • but also transparent to a broad range of wavelengths. The imaging data from these sensors can even

  • feed into the pilot’s helmet visor, which has been enhanced with augmented reality technology.

  • [18]This helmet alone costs four hundred thousand dollars, and enables the pilot to look straight

  • through the aircraft, and see at night without having to wear clumsy night vision goggles.

  • The helmet also feeds in data from the multitude of other sensors like the advanced high frequency

  • radar in the nose of the plane, along with data received from sensors from other aircraft

  • and ground based units. The data does not feed into the pilots AR Helmet unfiltered

  • though, it first passes through the onboard computer which performs all the necessary

  • filtering and data analysis and only presents the pilot with the information they really

  • needs. This technology is so powerful that even an unarmed F-35 would greatly boost the

  • combat effectiveness of its allies, but detection is just one step of that goal of shooting

  • first. Not being detected is just as important.

  • Incorporating stealth was just another challenge, and is likely the source of much of the unexpected

  • costs. Let’s first clear something up, despite what you may have otherwise heard, stealth

  • does not render a plane undetectable. Short of not physically existing, everything is

  • detectable. If we can find and analyse planets billions of lightyears away, we can detect

  • a plane flying directly overhead. Stealths purpose is not to make the plane invisible,

  • it serves to complicate and delay the enemies detection of an aircraft.

  • Stealth has proven itself invaluable over the past 2 decades prior to the F-35s inception.

  • The F-117 Nighthawk flew over 1,300 missions over Iraq during the Gulf War, scoring direct

  • hits on over 1,600 high value targets, without losing a single aircraft. [19]

  • But it was far from perfect. Lockheed knew this all to well as the manufacturer of the

  • F-117. In 1999, a Nighthawk was infamously spotted by radar and subsequently shot down

  • over Serbia. The pilot survived, but the plane crashed and remained mostly intact. Handing

  • over a valuable technology to the Russians to reverse engineer. Stealth serves a single

  • purpose, to avoid detection, and the F-117 failed here.

  • But it was developed using 1970s era computing technology. It’s panels were flat and faceted,

  • simply because we did not have computers capable of analysing more complicated shapes to optimize

  • stealth.

  • Early attempts at stealth worked under a fairly simple theory. Radar works by sending out

  • pulses of electromagnetic waves, and waits and listens for reflections. The idea behind

  • stealth technology is to not reflect those waves back at the emitter, and thus avoiding

  • detection. This is why the F-117 is shaped like this. Each panel has been angled and

  • placed in a way to minimise how much of this energy it will reflect back to the sender.

  • It was also coated in a paint that would help absorb some of that electromagnetic radiation.

  • Opponents of stealth technology, despite its proven track record, are quick to point out

  • that long wavelength radar is capable of detecting stealth aircraft. The same kind of radar that

  • detected the F-117 over Serbia, and the same kind of radar used in the Battle of Britain.

  • While this is true, these stealth aircraft are optimized to avoid detection of higher

  • frequency radar. Those opponents rarely mention that low frequency, long wavelength radar

  • do not provide high fidelity measurements, and struggle to pinpoint the location of the

  • aircraft. [20] This makes them effective early warning systems, but entirely useless for

  • directing missiles. While this is certainly not useless, it’s not particularly useful

  • in air to air combat. Had the F-117 Nighthawk, on that night been escorted by it’s usual

  • squadron of electronic jamming prowler aircraft, the missiles may well have never got a lock.

  • [21] This made worse by the fact the aircraft was flying on a regular flight path and so

  • the Serbians knew where to look.

  • Topping this off, the F-117 was designed in an era before sophisticated computational

  • analysis was available, and so it took this relatively simplistic flat faceted form. The

  • B-2 however greatly improved on the technology, utilizing complex curved shapes which no human

  • could hope to calculate the radar signature of, and it has never been shot down. [3] The

  • curves diffuse those radio waves in many directions, rather than reflecting it all in one direction,

  • which makes it easier to detect by receivers listening in locations separate to the emitter.

  • A fairly standard practice today. The F-35 uses the same complex curves to avoid detection