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Shadowing practice: The Insane Engineering of the F-35B

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  1. I've never flown an airplane like this where you can control the motion of the airplane so precisely.0:00
  2. I'm not sure we've even scratched the surface yet of what this airplane, when it's operating with other F -35, is going to be able to do.0:08
  3. The F -35B is arguably the most advanced plane ever made.0:15
  4. A jack of all trades.0:21
  5. A stealth fighter plane, combining and improving on the capabilities of the F -16, A V, A B Harrier and the B -2.0:22
  6. A highly manoeuvrable fighter plane, capable of attacking both airborne and ground based targets.0:31
  7. A stealth fighter taking the lessons learned from Lockheed's previous ventures into stealth with the F -22 Raptor and the F -117 Nighthawk.0:36
  8. A plane fitted with the most advanced sensors and computer systems, sharing information almost instantly with allies, without compromising stealth, and presenting the information directly on a heads -up display0:45
  9. on the pilot's helmet visor, giving unparalleled situational awareness, allowing a flight of F -35s to effectively fight as a hive might.0:57
  10. Perhaps most boldly of all, the F -35B is capable of transitioning from horizontal to vertical flight with a push of a button, using directional thrust and a massive vertical1:07
  11. turbofan engine hidden within the plane's body, making it possible to land like a helicopter on the relatively small and phibious assault ships of the US Marines.1:18
  12. This is the insane engineering of the F -35B.1:27
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  1. Fitting all these capabilities into a single airframe is an extremely difficult task.1:37
  2. Designing for stealth demands careful moulding of the exterior of the plane, dictating the design of crucial features, creating unavoidable trade -offs.1:43
  3. There are a lot of misconceptions about stealth.1:52
  4. The goal isn't to make the aircraft invisible, it will be detectable.1:56
  5. The goal is to delay enemy detection for as long as possible.2:00
  6. For bomber aircraft, it shrinks the range of the enemy's radar stations, potentially opening gaps in radar defences and allowing the aircraft to slip through undetected.2:05
  7. For fighter aircraft, it provides a critical advantage, detect your enemy before they detect you.2:15
  8. To gain these advantages, we need to make it harder for the radar receiver to decipher whether the return signal is just background noise or an enemy aircraft.2:20
  9. To do that, we need to minimise the strength of the return signal.2:30
  10. There are several mechanisms for a radar wave to be reflected.2:34
  11. The most significant and most obvious way is through spectral return, otherwise known as regular reflection, like a mirror, where the angle of reflection equals the angle of incidence.2:39
  12. We want to avoid large, flat surfaces that could reflect straight back to the radar receiver.2:49
  13. Corner reflectors, where two surfaces are set at a 90 degree angle to each other, need to be avoided at all costs.2:55
  14. Tail planes, consisting of the vertical and horizontal stabiliser, are the perfect surfaces to create a corner reflector, allowing radar to bounce off both surfaces and return right back in3:03
  15. the direction it came.3:14
  16. The best way to avoid this is to remove the tail completely, like the B2, but this impacts manoeuvrability greatly.3:15
  17. Instead, we can replace both the horizontal and vertical stabiliser with a V -tail, as seen on the F117 Nighthawk.3:22
  18. The V -tail can act as both a rudder and an elevator, and we can see how by examining the resultant force generated when the control surfaces are actuated to3:30
  19. different positions.3:39
  20. We can actuate them in opposite directions to generate a horizontal resultant force, providing yaw control as a vertical rudder wood, or we can deflect them in the same direction3:40
  21. to provide pitch control as a horizontal elevator wood.3:51
  22. This configuration is sometimes used for unique looking aircraft like the Cirrus SF -50, allowing it to mount a single tiny jet engine on top of the fuselage, with its3:55
  23. exhaust directed straight through the V -tail.4:05
  24. A private jet so tiny and lightweight that it can deploy a parachute to rescue itself in emergencies.4:07
  25. Having rudder and elevator controls linked to a single mechanism like this is not ideal.4:14
  26. Fighter jets like the F -35 and the F -22 need superior control authority, and that is a function of control surface area.4:20
  27. The larger the elevator, the larger the pitch control.4:28
  28. If a control surface is working a double roll, where rudder and elevator action is needed at the same time, it reduces the control authority.4:32
  29. So both planes also feature large elevators, offset by a distance and angle to prevent corner reflections.4:40
  30. We can see many more trade -offs in design by comparing the F -117 and the F -35 in the quest to fulfill both stealth and fighter requirements.4:47
  31. Both the F -117 and B -2 have their engine air intakes mounted on the upper surface of the plane, which prevents ground based radar from bouncing around inside the4:58
  32. intake and back to the receiver, and helps reduce infrared heat signatures.5:07
  33. However, for a plane expected to make high angle of attack maneuvers in life and death situations, this isn't a design you would want to include.5:11
  34. While performing a maneuver like this, the air intake will receive lower pressure air, which will lower performance right when performance is needed most.5:21
  35. Air intakes located underneath the aircraft, like the F -16, will cause too much radar return, so twin intakes located on either side of the fuselage are instead chosen.5:30
  36. These air intakes have some clever aerodynamic features too.5:40
  37. This seemingly innocuous bump plays an important role.5:45
  38. This is aeronautical engineering epitomized.5:48
  39. Every seemingly insignificant design feature has a purpose.5:51
  40. Mounting engine intakes along the body of an aircraft comes with some issues that pylon mounted engines avoid.5:55
  41. As air travels along the length of the body, air begins to form a layer of slow -moving, turbulent air called a boundary layer.6:02
  42. If air is allowed to enter the engine, it not only lowers performance, but it can also damage the engine.6:10
  43. As the turbine rotates, it will pass through the slow boundary air on one side and then fast -stream free air on the other.6:16
  44. This means the force on the turbine blade changes for each and every rotation, causing cyclical bending, a recipe for fatigue failure.6:23
  45. Planes like the F -16 feature a boundary layer diverter that separates the inlet from the fuselage with a small gap.6:32
  46. But this design increases radar cross -section and increases drag.6:39
  47. Later variants of the F -16 tested the DSI, the divertless supersonic inlet, essentially a large bump that creates a region of compression that pushes the boundary layer air away6:45
  48. from the inlet.6:57
  49. While also scattering incoming radar and lowering drag, the test flight demonstrated that it could meet performance requirements, ushering in its introduction to the F -35.6:58
  50. The F -35 product reduces weight by 30 % and lowers production and maintenance costs.7:09
  51. Moving down the plane, we can see other hints of stealth design.7:14
  52. Long, sharp edges are the enemy of stealth.7:18
  53. Sharp edges cause radar waves to scatter in all directions.7:21
  54. Radar can even travel along the length of a surface in the form of a travelling wave and then scatter upon reaching the trailing edge.7:25
  55. The strength of that return signal can be reduced with a few clever techniques.7:32
  56. The strength of the signal will depend on the length of the edge, so the first technique is to reduce the edge length with serration.7:37
  57. You can see this technique implemented very clearly on the trailing edge of the B2.7:45
  58. However, it's less obvious where it's used for the F -35, until you start looking at all the access hatches hidden around the aircraft.7:50
  59. Every single unavoidable surface gap on the aircraft has a serrated edge.7:59
  60. This hatch opens to reveal a telescoping ladder to allow pilots to climb in and out of the aircraft.8:03
  61. These open to reveal the landing gear.8:10
  62. These are the internal weapons bay, essential for keeping the radar reflecting missiles hidden from view.8:12
  63. And these smaller hatches are flare dispenser doors.8:18
  64. Flares are effective decoys for heat seeking missiles, but they do nothing to prevent radar guided missiles.8:21
  65. In the face of radar guided missile proliferation and continued growing sophistication in the technology, a new decoy system was developed.8:27
  66. This new technology is released from this panel.8:37
  67. When needed, this access door opens and a transmitter begins to reel out to a safe distance behind the plane.8:40
  68. It has three levels of countermeasures to protect the F -35 from attack.8:47
  69. First, it actively jams missiles while they attempt to lock onto their target, by emitting jamming signals which the onboard computer computes and delivers to the emitter through the fiber8:51
  70. optic tow line.9:03
  71. If the radar manages to obtain a lock, it then begins to attempt to break the lock, disrupting the tracking algorithms guiding the missile towards its target.9:04
  72. Finally, if all is lost and the missile is bearing down on the aircraft, the emitter begins to simulate the aircraft's radar signature, drawing the missile toward it as a9:12
  73. decoy.9:23
  74. These serrated hatches hide critical components of the F -35, but more can be done to reduce edge scattering in these locations.9:24
  75. You may notice that the color around these edges is different to the rest of the plane.9:32
  76. This is because the edges are treated with a special radar scattering tape.9:38
  77. In the same way traveling waves scatter when they meet an edge discontinuity, they will scatter when traveling over a change in conductivity.9:43
  78. The F -35 uses this to its advantage to scatter waves over in longer distance, reducing the return signal by spreading it out.9:50
  79. The tape has a conductivity gradient, gradually decreasing its electrical conductivity, causing radar waves to scatter at each interval, slowly decreasing the intensity of the surface wave before it reaches9:59
  80. the edge where would have released one large return if the tape was not present.10:11
  81. The surface of the plane itself is also composed of a specialized radar absorbing material.10:16
  82. In 2010 Lockheed Martin filed this patent for a carbon nanotube -infused composite material that can absorb radar waves from 0 .1 MHz through to 60 GHz.10:21
  83. This is an incredibly wide range of frequencies, notably covering the frequencies Russian surface -to -air missiles like the advanced S -400 system uses.10:33
  84. The effect traveling surface waves have on stealth design can be seen elsewhere.10:43
  85. You would imagine a cylinder would be a great way to scatter radar in all directions, lowering the strength of the return signal.10:47
  86. But if a radar wave comes in tangentially to a cylinder and the wavelength is at least 1 -tenth the cylinder's circumference, the wave can actually travel around the outside10:54
  87. of the cylinder and travel straight back to the receiver.11:03
  88. This is likely why the F -35 features a sharp edge breaking up the circular nose cone.11:06
  89. Where the F -16 has a nearly perfect circular nose cone, the F -35 features a ridge.11:12
  90. The largest hatch on the plane is strangely not serrated, and this is for good reason.11:18
  91. This hatch hides the powerful lift fan within.11:24
  92. The airflow in and out of this lift fan needs careful consideration.11:26
  93. The lift fan is essentially a tiny helicopter, capable of generating 85 kN of vertical thrust and in doing so creates a low pressure zone above the plane, violently sucking11:30
  94. air into the aircraft at a 90 degree angle.11:41
  95. This air has to travel over the hood to reach the inlet, and thus the hood needs to allow air to smoothly pass over it without creating too much turbulent11:45
  96. flow, which would lower the performance of the lift fan.11:53
  97. This is why the inlet door is not serrated, as the sharp edges would cause distortions in the flow.11:56
  98. This hood alone went through several design iterations to optimize the airflow flowing over it.12:02
  99. The demonstration X -35 aircraft had two doors opening towards the side of the aircraft, but this was changed for the final aircraft in favour of a rear hinged door.12:08
  100. This helps funnel air into the engine and improves pressure recovery on short takeoffs where the F -35B does not take off vertically, instead using the lift fan and directional12:18
  101. thrust of the rear nozzle to take off on extremely short runways.12:29
  102. The way this aircraft transforms to perform vertical landing and short takeoffs is astounding.12:33
  103. It's the closest thing to a transformer we have ever created.12:39
  104. When the time comes, a clutch linking the extended driveshaft of the F -35's engine begins to transfer 29 ,000 horsepower to the bevel gear of the lift fan, spinning12:43
  105. the counter -rotating lift fan blades.12:54
  106. Simultaneously, gears begin to rotate in the rear exhaust nozzle.12:57
  107. The mechanics of this nozzle are another wondered behold.13:02
  108. Called the three bearing swivel nozzle, it is composed of three airtight segments cut at angles relative to one another.13:05
  109. The three can change the shape of the nozzle by rotating these angled pieces separately.13:13
  110. These three pieces rotate together to smoothly transition thrust downwards, but it's easier to understand how it works by seeing what happens when we rotate segments individually.13:17
  111. Rotating the central piece can take the nozzle from 0 degrees down to 45 degrees.13:28
  112. This position is used for short takeoffs, splitting the engine's power between thrust and lift.13:33
  113. This mode is as impressive as the vertical takeoffs, allowing the plane to operate from shorter amphibious assault ships like the USS Macon Island, a ship just 258 meters long.13:38
  114. Its minimum takeoff distance decreases even further with the aid of a ski jump, a ramp that has been added to smaller amphibious assault ships.13:51
  115. Watching the F -35 takeoff over such short distances is incredible.13:59
  116. In this clip, we can see the rear nozzle quickly adjusting its angle of thrust in sync with the rear elevators to adjust the pitch of the plane to ensure14:04
  117. a safe takeoff.14:13
  118. For a vertical landing, the final nozzle segment can rotate to provide the full 90 degree turn.14:15
  119. The first nozzle segment can rotate to move the nozzle from side to side, but here it's needed to ensure the thrust doesn't move sideways as the nozzle transitions.14:21
  120. As we saw, when we rotate the segments individually, they move in an arc that would cause the F -35 to spin out of control.14:30
  121. This mechanism also allows the F -35 to smoothly transition from cruise to vertical flight and from vertical flight to cruise when needed.14:38
  122. There are additional control mechanisms to ensure this precarious balancing act does not go wrong.14:47
  123. Bleed air from the main engine bypass is siphoned to two roll nozzles located on each wing, providing thrust far away from the plane's centre of pressure to control roll.14:53
  124. There are also guide veins located underneath the lift fan.15:04
  125. These can adjust the outlet area to adjust the performance of the lift fan, but can also control the thrust of the lift fan from 5 degrees forward to 4215:08
  126. degrees backwards.15:17
  127. With computer assisted control of these control mechanisms, the F -35 is remarkably stable compared to its predecessor, the AV -8B Harrier, allowing the single engine of the F -3515:18
  128. to hover on two columns of air.15:30
  129. To do this, the F -35's engine, the F -135, developed from the F -119 engine of the F -22 Raptor, had to be incredibly powerful.15:32
  130. The F -22 Raptor is a twin -engine fighter, giving it plenty of excess power to pull off incredible manoeuvres.15:42
  131. The F -35 only has one engine, and needs to squeeze out all the power it can get to perform a vertical landing.15:49
  132. Where the F -22's engine can generate 156 kN of thrust, the F -35's can generate 191.15:57
  133. The F -35's engine has a much larger fan and bypass ducting, giving it twice the bypass ratio of its F -22 counterpart, providing the F -35 with a more16:05
  134. efficient engine for cruise, but also a higher mass flow rate for higher thrust.16:15
  135. However, this does come with some drawbacks.16:20
  136. Air that travels around the engine core completely avoids the combustion chamber, and thus misses out on the acceleration generated there, reducing the exhaust velocity.16:23
  137. This reduces the top speed of the plane.16:34
  138. The max speed of the F -35 is 1 .6 Mach, and while it's the first plane capable of vertical flight and supersonic flight, the F -22 can fly at16:37
  139. 2 .2 Mach.16:46
  140. The F -35 was optimized for loiter time, not speed.16:47
  141. However, all that extra weight needed for vertical takeoff seriously hampers that ideology.16:51
  142. The lift fan module weighs 1 .2 tons, weight that does nothing in normal flight, and requires more fuel to carry, and to make matters worse, that space is used16:56
  143. for internal fuel tanks for its variants.17:07
  144. Making the lift fan as light as possible was pertinent to making the F -35B viable in the battlefield.17:10
  145. The fact it only weighs 1 .2 tons is astounding.17:17
  146. It contains two counter -rotating titanium blisks.17:20
  147. Blisk meaning the blades and disc are all one single piece, instead of the traditional alternative of creating a disc and attaching blades through dovetail connections.17:24
  148. This improves efficiency and eliminates a potential sight of failure in the connection.17:34
  149. This is an astounding feat of manufacturing, and the first stage fan takes it even further.17:39
  150. The first stage blades are hollow to save weight.17:44
  151. Where the F -35B truly comes into its own however, is in its modern suite of sensors and computers, all feeding into this, the heads -up display incorporated into the17:46
  152. pilot's helmet.17:57
  153. Traditional heads -up displays like those of the F -16 are incorporated into a panel in the cockpit, a panel which the pilot can't see while scanning their environment.17:59
  154. Situational awareness is everything in the heat of combat, and this helmet does everything it can to keep the pilot informed, even giving them X -ray vision and night vision.18:08
  155. Information from a suite of sensors around the plane feed into a central computer, where it is processed and displayed through a projector inside the helmet.18:19
  156. Inside this transparent faceted box underneath the aircraft is a suite of sensors, but those are not your typical windows.18:27
  157. These windows are made from a notoriously expensive gemstone, sapphire.18:34
  158. One of the few materials that is both hard and durable, but also transparent to a broad range of electromagnetic wavelengths, from ultraviolet to infrared.18:40
  159. However, the radar antenna hidden inside the nose of the F -35 is the most important part of this electronic system.18:49
  160. This is a scanned array radar that works very differently to traditional mechanical radar.18:57
  161. Phased array antennas have hundreds of tiny antennas.19:02
  162. We can see metal plates set in rows in the F -35 Phase array antenna.19:06
  163. The metal plates have slots cut into them, and each and every one of these slots is an antenna, 1 ,600 in total.19:11
  164. This allows the Phase array antenna to steer its radar using constructive and destructive interference.19:19
  165. If two antenna release two radar waves at the exact same time with their peaks and troughs lined up, it will result in constructive interference, increasing the amplitude of the19:25
  166. radio wave.19:36
  167. However, if the radio waves are set 180 degrees out of phase, matching the peaks to troughs, it will result in complete destructive interference, cancelling out the wave completely.19:37
  168. This is how noise -canceling earphones work.19:48
  169. They listen to the background noise and then release a cancelling sound wave to create silence.19:52
  170. Phased array antenna use this phenomenon to steer the radio waves, preventing the radar from becoming a joint beacon, leading enemies straight to it.19:57
  171. Traditional Phase array antennas are passive, meaning every antenna in the array is driven by a single transmitter and receiver.20:06
  172. This would mean it can only point in one direction, and if it encountered two enemy planes flying side by side and they split up, the passive phased array antenna20:14
  173. would no longer be able to track both of them.20:23
  174. However, the F -35's phase array antenna is an active phased array, meaning each and every one of these antenna is an individually driven transmitter and receiver, meaning the F20:26
  175. -35 can track multiple targets at once with zero moving parts.20:38
  176. The nose cones hiding these antenna need to be transparent to radar waves, and are usually made from glass fibre composites as a result.20:42
  177. This transparency causes issues for the plane's radar return signature, as an antenna like this will reflect signals.20:50
  178. This was a much bigger issue for mechanical radar dishes that needed to point at the enemy to keep track of them.20:57
  179. The phased array can point towards multiple targets while staying in a single position, and this is why it is pointed skywards, to bounce incoming radar to space.21:03
  180. The phased array antenna also acts as the plane's communication antenna, and this is critical to the F -35's battle doctrine.21:14
  181. The F -35 excels in battle because of its networking abilities, relaying information between its squadron.21:21
  182. This is a huge amount of data to transfer between aircraft and allies on the surface, and requires a high data transfer speed.21:28
  183. However, communication comes with one glaring problem, it announces your presence to anyone listening.21:36
  184. It is vital that stealth planes can communicate with each other securely, and the active phased array antenna facilitates this.21:42
  185. The F -35 uses the latest data link system, MADL, improving on the experiences learned with the F -22, allowing the F -35 to quickly share data securely from individual21:49
  186. F -35's and ground based systems.22:02
  187. This information is then sorted by the computer and presented to the pilot in their heads up display right in front of their eyes, giving them unparalleled situational awareness.22:05
  188. There is no need to communicate with their wing mates if there is an adversary underneath them.22:14
  189. The planes communicate and feed that data right into the helmet, allowing the pilot to look underneath the plane and see the location of the adversary themselves.22:20
  190. This is the true strength of the F -35B.22:29
  191. It is a networked hive mind stealth fighter, capable of taking off from a ship a fraction of the size of an aircraft carrier, and returning while hovering in the22:32
  192. sky like a helicopter.22:41
  193. It's one of the most remarkable pieces of military technology ever created.22:42
  194. The F -35 has borrowed many lessons learned from planes like the F -117 Nighthawk and B -2, planes that we have not made documentaries about yet, but are friends22:48
  195. over at Mustard Half.22:58
  196. Their B -2 documentary is 20 minutes of beautifully crafted story filled with stylish 3D renders.22:59
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Irish narration on the F-35B: english listening practice at C1

This is english listening practice that stays on one voice for a long stretch. Real Engineering narrates the design of the F-35B, so what you hear is written prose read aloud by a native speaker, not conversation. The narrator is Irish, which is worth your attention: the vowels and the r sounds sit differently from the American voices most learners train on, and following an accent you have not memorised is the point.

The recording is graded C1 and runs at 170 words per minute, faster than 35 percent of our catalogue. It opens with two pilot quotes, then the narrator lists what the aircraft can do, and by the middle of the opening the subject narrows to radar. There are 225 lines, so you never need to take the clip whole. Take a run of four and stay there.

Sentences built on contrast: shadowing english speaking practice c1

For shadowing english speaking practice c1 material, the radar section is the best place to start, because almost every sentence is a contrast and the stress falls where the contrast falls.

  • "There are a lot of misconceptions about stealth." A short reset after a long list. The weight is on the one long word, and everything before it flattens out. Say the first four words quickly or the line will not sound like speech.
  • "The goal isn't to make the aircraft invisible, it will be detectable." Two clauses, one comma, no conjunction. The pitch drops on the comma rather than stopping. The contracted "isn't" carries the negative, and if you say "is not" the sentence loses its shape.
  • "The goal is to delay enemy detection for as long as possible." The same three words open this line as the last one, so the new information is the verb, and that is where the pitch rises. Say the two lines back to back and you can hear the shift.
  • "To do that, we need to minimise the strength of the return signal." A cleaner sentence to work on if you want to improve your english accent: one clear stress per phrase, and a natural pause after "that".

How to work through the F-35B radar lines, four at a time

Practise english speaking here in small blocks, free and online in your browser, with the subtitles on for the first pass and off afterwards. An order that works on this clip:

  • Play "There are a lot of misconceptions about stealth." three times before you say anything. Listen for where the voice speeds up, not for the words.
  • Shadow this line from its second half: say only "about stealth", then add the front of it.
  • Move to "The goal isn't to make the aircraft invisible, it will be detectable." and record it five times. Keep the comma as a dip in pitch, not a pause.
  • Put the two goal lines together and speak them as one unit. That pair teaches you the rhythm of the whole section.
  • Only then go back to the opening. "A jack of all trades." is four words and harder than it looks, because the whole phrase runs together at speed.
  • Finish on "Fitting all these capabilities into a single airframe is an extremely difficult task." It is the longest subject in the section, and it will show you whether you can hold a phrase without breathing in the middle of it.
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