Drones, hypersonic weapons, lasers and engines for next generation

The sixth generation fighters and upgrades to older fighters over the next 10-20 years will involve better engines for more range and speed, hypersonic weapons, combat lasers, unmanned flight and drones.

Hypersonic missiles (mach 5 or faster) are already being introduced by Russia and China. The US is developing combat laser pods which will be added to fighter jets. Unmanned flight is being used for various planes. Large drones are being deployed to help with refueling existing military planes. Future large drones will fight alongside future fighter planes.

It will be another 10 years after that for hypersonic drones and hypersonic planes that will define the seventh generation of fighters.

Challenge of better fighter engines

Engines are the key to fighter jet performance. Speed and range all depend upon the power and efficiency of the engines.

Better materials, improved manufacturing, 3D printing of parts are needed for higher temperature and pressure levels.

The Air Force Research Lab has the Adaptive Engine Transition and the Adaptive Engine Technology Development programs for fighter engines with 25% less fuel consumption and improved heat absorption by 60%. This would increase the range of the F-35 and other planes by 35% and enable them to stay over a target for 50% longer.

New GE and Pratt Whitey engines will also have 12% more thrust over the existing F-35 engine.

GE and Pratt Whitney have been given contracts that are part of the final phase. $1.5 billion will be needed to complete the final prototypes and engine development.

Afterwards many billions will be needed for Engineering, Manufacturing, and Development (EMD) to re-engine various planes.

Previous Five Generations of Fighter Jets

First generation subsonic jet fighters (mid 1940s to mid 1950s)

The first generation of jet fighters such as the F-86, MiG-15and MiG-17, had basic avionic systems with no radars or self-protection countermeasures, and were armed with machine guns or cannons, as well as unguided bombs and rockets. A common characteristic of this generation of fighter was that the jet engines did not have afterburners and the aircraft operated in the subsonic regime.

Second generation jet fighters (mid-1950s to early 1960s)

The second generation fighters had air-to-air radar, infrared and semi-active guided missiles, as well as radar warning receivers. The second generation jets were F-104, F-5, MiG-19 and MiG-21. They could sustain supersonic speeds in level flight. Air-to-air combat was within visual range but radar-guided missiles started to extend engagement ranges.

Third generation jet fighters (early 1960s to 1970)

This generation had improved manoeuvrability and better avionic suites and weapon systems. The multi-role fighters like MiG-23, F-4, and Mirage III were third generation. Doppler radar and guided radio-frequency missiles like the AIM-7 Sparrow and AA-7 Apex moved combat beyond the visual range.

Fourth generation jet fighters (1970 to late 1980s)

These planes had head-up displays, better aerodynamic design and ‘fly by wire’. The MiG-29, Su-27, F/A-18, F-15, F-16, and Mirage-2000 were the dominant fourth generation fighters. They could attack air-to-air and air-to-ground.

Four and half generation jet fighters (late 1980s and into the 90s)

The F/A-18E/F Super Hornet is an example of a 4.5 generation fighter evolved from a fourth generation aircraft. Active Electronically Scanned Array (AESA) radar was added to enable some detection of enemy stealth fighters. The 4.5 fighters also had some stealth capabilities and extended ranges. They also had better networking between planes and ground support and better electronics.

Fifth generation jet fighters (2005 to date)
The F-22 Raptor and F-35 are fifth-generation fighters. They have full stealth capabilities and a lot of electronics and complex computer software. China’s J-20 with its new engine might be considered fifth-generation.

Sixth generation fighters

The sixth generation fighters will involve better engines for more range and speed, hypersonic weapons, combat lasers, unmanned flight and fight with wing-man drones.

Seventh generation fighters

These will likely be hypersonic planes able to fly beyond mach 5.

60 thoughts on “Drones, hypersonic weapons, lasers and engines for next generation”

  1. I know… the “dopey bandwagon” seems to be hopped on at every level of civilization. Find something new, and keep name-dropping it into the conversation to sound current. I’m surprised they didn’t spring Quantum Computing and Blockchain for Greater reliability. Because, you know, those are hip (hop) words. GoatGuy

    Reply
  2. It is VERY unlikely that the “Seventh Generation” will be aircraft flying in excess of Mach 5. Several reasons work against such aircraft: • № 1: skin heating stealth • № 2: engine inflow heating • № 3: sharp edges stealth • № 4: need to be 20+ km flight path • № 5: lousy handling at speed There likely are more, but those are the basics. № 1: skin heating stealth → deep into the supersonic comes greater supersonic ‘berm’ and laminar turbulence heating. The super-stealth planes have soft, porous, electromagnetically resistive coatings to make them black in RADAR. These coatings tend not to do well when heated. № 2: engine inflow heating → SR–71 Blackbird found that above Mach 3.5 (the limit of the design) the inlet would compress the air where the front vanes of the jet engine compressor would overheat. Of course, at the CENTER of the ‘bird’ were 5 primary technologies: • A: The engine • B: The super-sharp skin • C: The inlet nacelles • D: The avionics • E: The leaky airframe The engine had to work with inlet compression up to 5 over ambient, with temperatures up to 700° C. This was extraordinary because in the engine, inlet gas had to be compressed far further, to get thrust at high supersonic velocities. The “shape of the plane” had to have very sharp edges, very swept wing surfaces, nothing at all “sticking out”. The very thinness of the skin required special bonding. It was a work of art. The inlet nacelles (air scoops) of the engines had to be maneuverable to “point into the airstream”. This was a major innovation which used the speed of the plane to compress the inlet stream BEFORE the engine. Where its heat could be dissipated safely. Avionics had to work at air pressures far below commercial service — or even military — were capable of. This in turn required hermetically sealed avionics with 5,000 meter interior pressure, and helium sa the working gas. Very costly. Very necessary. Very hard to repair. Then the whole

    Reply
  3. I know… the dopey bandwagon”” seems to be hopped on at every level of civilization. Find something new”” and keep name-dropping it into the conversation to sound current. I’m surprised they didn’t spring Quantum Computing and Blockchain for Greater reliability. Because you know”” those are hip (hop) words. GoatGuy”””

    Reply
  4. US government just placed and order on 141 F35 jets. The price is the lowest it has ever been at 90 million for F35A. Projected to get to 80 million by 2030. Lockheed of course is making more of them to supply to other NATO members and Israel.

    Reply
  5. As an alternative idea to manned fighters, we might consider a large airframe carrying a megawatt class laser, or a powerful railgun or coilgun. Such an airplane will have the ability to attack targets from ground level to low earth orbit, and deliver effects at speeds far exceeding the ability of any target to escape. They may still need F-35’s to fly ahead and scout out targets in some scenarios.

    Reply
  6. US government just placed and order on 141 F35 jets. The price is the lowest it has ever been at 90 million for F35A. Projected to get to 80 million by 2030. Lockheed of course is making more of them to supply to other NATO members and Israel.

    Reply
  7. As an alternative idea to manned fighters we might consider a large airframe carrying a megawatt class laser or a powerful railgun or coilgun.Such an airplane will have the ability to attack targets from ground level to low earth orbit and deliver effects at speeds far exceeding the ability of any target to escape. They may still need F-35’s to fly ahead and scout out targets in some scenarios.

    Reply
  8. WASHINGTON — The price of a conventional F-35A model has fallen below $90 million for the first time through a deal announced Sept. 28 between the Pentagon and Lockheed Martin. The Defense Department’s F-35 Joint Program Office and F-35 prime contractor Lockheed have finalized an $11.5 billion contract for the 11th batch of F-35s. The deal comprises 141 new jets and follows a handshake deal between the two parties that was announced in July. The agreement pushes the cost of the F-35A conventional model — used by the U.S. Air Force and most foreign buyers — to $89.2 million per aircraft, a 5.4 percent reduction from the $94.3 million in the 10th batch of aircraft. Pentagon reaches handshake deal with Lockheed on newest batch of F-35s The Pentagon makes its biggest F-35 order yet. The more expensive “B” and “C” models incurred even bigger price cuts. The Marine Corps’ F-35B short-takeoff-and-vertical-landing variant’s cost decreased 5.7 percent from $122.4 million to $115.5 million, while the F-35C carrier variant dropped a whopping 11.1 percent from $121.2 million to $107.7 million per unit. Greg Ulmer, Lockheed’s F-35 vice president and general manager. “As production ramps up and we implement additional cost savings initiatives, we are on track to reduce the cost of the F-35A to $80 million by 2020, which is equal to or less than legacy aircraft, while providing a major leap in capability.”

    Reply
  9. WASHINGTON — The price of a conventional F-35A model has fallen below $90 million for the first time through a deal announced Sept. 28 between the Pentagon and Lockheed Martin.The Defense Department’s F-35 Joint Program Office and F-35 prime contractor Lockheed have finalized an $11.5 billion contract for the 11th batch of F-35s. The deal comprises 141 new jets and follows a handshake deal between the two parties that was announced in July.The agreement pushes the cost of the F-35A conventional model — used by the U.S. Air Force and most foreign buyers — to $89.2 million per aircraft a 5.4 percent reduction from the $94.3 million in the 10th batch of aircraft.Pentagon reaches handshake deal with Lockheed on newest batch of F-35s The Pentagon makes its biggest F-35 order yet.The more expensive B”” and “”””C”””” models incurred even bigger price cuts. The Marine Corps’ F-35B short-takeoff-and-vertical-landing variant’s cost decreased 5.7 percent from $122.4 million to $115.5 million”” while the F-35C carrier variant dropped a whopping 11.1 percent from $121.2 million to $107.7 million per unit.Greg Ulmer Lockheed’s F-35 vice president and general manager. “As production ramps up and we implement additional cost savings initiatives we are on track to reduce the cost of the F-35A to $80 million by 2020 which is equal to or less than legacy aircraft”” while providing a major leap in capability.””””””””

    Reply
  10. 1. Given the secrecy behind stealth, I wouldn’t rule it out unless we have a major war with no stealth in operation. Until then it’s always possible that everyone says it doesn’t work, but actually have secret projects going on in the background. See F-117 2. Actually the SR71 engines already (back in Granddad’s time) had a way around this problem. Shut off the air supply to the compressors once you get fast enough and run as a ramjet. 4. I think you misinterpreted Goat’s #4. He was talking about the high altitudes needed for the high speeds, not acceleration. But why is high altitude a show stopper? Because it makes stealth more difficult (see 1 and 3)? Because what you can do at 20km+ is not relevant to how you interact with other aircraft that aren’t that high? (But you can launch missiles from up there, both down towards ground huggers and up towards space assets.) 5. I think you both missed the point. Instability doesn’t help if you don’t have a lot of air to push you around, but with directed thrust nozzles you don’t need aerodynamics to get sideways. But, as you point out, this would be more of a missile sled than a dogfighter.

    Reply
  11. 1. Given the secrecy behind stealth I wouldn’t rule it out unless we have a major war with no stealth in operation. Until then it’s always possible that everyone says it doesn’t work but actually have secret projects going on in the background. See F-1172. Actually the SR71 engines already (back in Granddad’s time) had a way around this problem. Shut off the air supply to the compressors once you get fast enough and run as a ramjet.4. I think you misinterpreted Goat’s #4. He was talking about the high altitudes needed for the high speeds not acceleration. But why is high altitude a show stopper? Because it makes stealth more difficult (see 1 and 3)? Because what you can do at 20km+ is not relevant to how you interact with other aircraft that aren’t that high? (But you can launch missiles from up there both down towards ground huggers and up towards space assets.)5. I think you both missed the point. Instability doesn’t help if you don’t have a lot of air to push you around but with directed thrust nozzles you don’t need aerodynamics to get sideways. But as you point out this would be more of a missile sled than a dogfighter.

    Reply
  12. 1 and 3 aren’t issues, stealth is losing viability with advanced radars. Its already been suggested that 7th G fighters will exist in a post-stealth near peer world. 2 is a non issue, that’s design specific to SR71 engines 4 is debatable, acceleration time is design specific 5 is just plain not true. Aerodynamic instability in fighter design is specifically for this purpose, creating high G turning ability. But even so, this is not what a hypersonic fighter would be for. It would be for outrunning SAMs.

    Reply
  13. 1 and 3 aren’t issues stealth is losing viability with advanced radars. Its already been suggested that 7th G fighters will exist in a post-stealth near peer world.2 is a non issue that’s design specific to SR71 engines4 is debatable acceleration time is design specific5 is just plain not true. Aerodynamic instability in fighter design is specifically for this purpose creating high G turning ability. But even so this is not what a hypersonic fighter would be for. It would be for outrunning SAMs.

    Reply
  14. 1. Given the secrecy behind stealth, I wouldn’t rule it out unless we have a major war with no stealth in operation. Until then it’s always possible that everyone says it doesn’t work, but actually have secret projects going on in the background. See F-117

    2. Actually the SR71 engines already (back in Granddad’s time) had a way around this problem. Shut off the air supply to the compressors once you get fast enough and run as a ramjet.

    4. I think you misinterpreted Goat’s #4. He was talking about the high altitudes needed for the high speeds, not acceleration. But why is high altitude a show stopper? Because it makes stealth more difficult (see 1 and 3)? Because what you can do at 20km+ is not relevant to how you interact with other aircraft that aren’t that high? (But you can launch missiles from up there, both down towards ground huggers and up towards space assets.)

    5. I think you both missed the point. Instability doesn’t help if you don’t have a lot of air to push you around, but with directed thrust nozzles you don’t need aerodynamics to get sideways. But, as you point out, this would be more of a missile sled than a dogfighter.

    Reply
  15. Railgun and megawatt laser armed aircraft will be for one type of target set, targets that are distant, fast moving or hardened. Sharpshooting drones are equally possible, but are low level tactical weapons and assets.

    Reply
  16. Railgun and megawatt laser armed aircraft will be for one type of target set targets that are distant fast moving or hardened. Sharpshooting drones are equally possible but are low level tactical weapons and assets.

    Reply
  17. Well, there was the recent patent for a B-1B with a deployable gatlng gun belly turret… Infrastructure to support a laser vs a railgun is different, though different uses of capacitor banks. Considering the work by DARPA to make .50cal guided ammunition, one could imagine drones sharpshooting from the sky, for a very minimal collateral damage attack without needing to resort to railguns.

    Reply
  18. Well there was the recent patent for a B-1B with a deployable gatlng gun belly turret…Infrastructure to support a laser vs a railgun is different though different uses of capacitor banks. Considering the work by DARPA to make .50cal guided ammunition one could imagine drones sharpshooting from the sky for a very minimal collateral damage attack without needing to resort to railguns.

    Reply
  19. 1 and 3 aren’t issues, stealth is losing viability with advanced radars. Its already been suggested that 7th G fighters will exist in a post-stealth near peer world.

    2 is a non issue, that’s design specific to SR71 engines

    4 is debatable, acceleration time is design specific

    5 is just plain not true. Aerodynamic instability in fighter design is specifically for this purpose, creating high G turning ability. But even so, this is not what a hypersonic fighter would be for. It would be for outrunning SAMs.

    Reply
  20. Railgun and megawatt laser armed aircraft will be for one type of target set, targets that are distant, fast moving or hardened. Sharpshooting drones are equally possible, but are low level tactical weapons and assets.

    Reply
  21. Well, there was the recent patent for a B-1B with a deployable gatlng gun belly turret…

    Infrastructure to support a laser vs a railgun is different, though different uses of capacitor banks. Considering the work by DARPA to make .50cal guided ammunition, one could imagine drones sharpshooting from the sky, for a very minimal collateral damage attack without needing to resort to railguns.

    Reply
  22. WASHINGTON — The price of a conventional F-35A model has fallen below $90 million for the first time through a deal announced Sept. 28 between the Pentagon and Lockheed Martin. The Defense Department’s F-35 Joint Program Office and F-35 prime contractor Lockheed have finalized an $11.5 billion contract for the 11th batch of F-35s. The deal comprises 141 new jets and follows a handshake deal between the two parties that was announced in July. The agreement pushes the cost of the F-35A conventional model — used by the U.S. Air Force and most foreign buyers — to $89.2 million per aircraft, a 5.4 percent reduction from the $94.3 million in the 10th batch of aircraft. Pentagon reaches handshake deal with Lockheed on newest batch of F-35s The Pentagon makes its biggest F-35 order yet. The more expensive “B” and “C” models incurred even bigger price cuts. The Marine Corps’ F-35B short-takeoff-and-vertical-landing variant’s cost decreased 5.7 percent from $122.4 million to $115.5 million, while the F-35C carrier variant dropped a whopping 11.1 percent from $121.2 million to $107.7 million per unit. Greg Ulmer, Lockheed’s F-35 vice president and general manager. “As production ramps up and we implement additional cost savings initiatives, we are on track to reduce the cost of the F-35A to $80 million by 2020, which is equal to or less than legacy aircraft, while providing a major leap in capability.”

    Reply
  23. WASHINGTON — The price of a conventional F-35A model has fallen below $90 million for the first time through a deal announced Sept. 28 between the Pentagon and Lockheed Martin.The Defense Department’s F-35 Joint Program Office and F-35 prime contractor Lockheed have finalized an $11.5 billion contract for the 11th batch of F-35s. The deal comprises 141 new jets and follows a handshake deal between the two parties that was announced in July.The agreement pushes the cost of the F-35A conventional model — used by the U.S. Air Force and most foreign buyers — to $89.2 million per aircraft a 5.4 percent reduction from the $94.3 million in the 10th batch of aircraft.Pentagon reaches handshake deal with Lockheed on newest batch of F-35s The Pentagon makes its biggest F-35 order yet.The more expensive B”” and “”””C”””” models incurred even bigger price cuts. The Marine Corps’ F-35B short-takeoff-and-vertical-landing variant’s cost decreased 5.7 percent from $122.4 million to $115.5 million”” while the F-35C carrier variant dropped a whopping 11.1 percent from $121.2 million to $107.7 million per unit.Greg Ulmer Lockheed’s F-35 vice president and general manager. “As production ramps up and we implement additional cost savings initiatives we are on track to reduce the cost of the F-35A to $80 million by 2020 which is equal to or less than legacy aircraft”” while providing a major leap in capability.””””””””

    Reply
  24. US government just placed and order on 141 F35 jets. The price is the lowest it has ever been at 90 million for F35A. Projected to get to 80 million by 2030. Lockheed of course is making more of them to supply to other NATO members and Israel.

    Reply
  25. US government just placed and order on 141 F35 jets. The price is the lowest it has ever been at 90 million for F35A. Projected to get to 80 million by 2030. Lockheed of course is making more of them to supply to other NATO members and Israel.

    Reply
  26. As an alternative idea to manned fighters, we might consider a large airframe carrying a megawatt class laser, or a powerful railgun or coilgun. Such an airplane will have the ability to attack targets from ground level to low earth orbit, and deliver effects at speeds far exceeding the ability of any target to escape. They may still need F-35’s to fly ahead and scout out targets in some scenarios.

    Reply
  27. As an alternative idea to manned fighters we might consider a large airframe carrying a megawatt class laser or a powerful railgun or coilgun.Such an airplane will have the ability to attack targets from ground level to low earth orbit and deliver effects at speeds far exceeding the ability of any target to escape. They may still need F-35’s to fly ahead and scout out targets in some scenarios.

    Reply
  28. I know… the “dopey bandwagon” seems to be hopped on at every level of civilization. Find something new, and keep name-dropping it into the conversation to sound current. I’m surprised they didn’t spring Quantum Computing and Blockchain for Greater reliability. Because, you know, those are hip (hop) words. GoatGuy

    Reply
  29. I know… the dopey bandwagon”” seems to be hopped on at every level of civilization. Find something new”” and keep name-dropping it into the conversation to sound current. I’m surprised they didn’t spring Quantum Computing and Blockchain for Greater reliability. Because you know”” those are hip (hop) words. GoatGuy”””

    Reply
  30. It is VERY unlikely that the “Seventh Generation” will be aircraft flying in excess of Mach 5. Several reasons work against such aircraft: • № 1: skin heating stealth • № 2: engine inflow heating • № 3: sharp edges stealth • № 4: need to be 20+ km flight path • № 5: lousy handling at speed There likely are more, but those are the basics. № 1: skin heating stealth → deep into the supersonic comes greater supersonic ‘berm’ and laminar turbulence heating. The super-stealth planes have soft, porous, electromagnetically resistive coatings to make them black in RADAR. These coatings tend not to do well when heated. № 2: engine inflow heating → SR–71 Blackbird found that above Mach 3.5 (the limit of the design) the inlet would compress the air where the front vanes of the jet engine compressor would overheat. Of course, at the CENTER of the ‘bird’ were 5 primary technologies: • A: The engine • B: The super-sharp skin • C: The inlet nacelles • D: The avionics • E: The leaky airframe The engine had to work with inlet compression up to 5 over ambient, with temperatures up to 700° C. This was extraordinary because in the engine, inlet gas had to be compressed far further, to get thrust at high supersonic velocities. The “shape of the plane” had to have very sharp edges, very swept wing surfaces, nothing at all “sticking out”. The very thinness of the skin required special bonding. It was a work of art. The inlet nacelles (air scoops) of the engines had to be maneuverable to “point into the airstream”. This was a major innovation which used the speed of the plane to compress the inlet stream BEFORE the engine. Where its heat could be dissipated safely. Avionics had to work at air pressures far below commercial service — or even military — were capable of. This in turn required hermetically sealed avionics with 5,000 meter interior pressure, and helium sa the working gas. Very costly. Very necessary. Very hard to repair. Then the whole

    Reply
  31. WASHINGTON — The price of a conventional F-35A model has fallen below $90 million for the first time through a deal announced Sept. 28 between the Pentagon and Lockheed Martin.
    The Defense Department’s F-35 Joint Program Office and F-35 prime contractor Lockheed have finalized an $11.5 billion contract for the 11th batch of F-35s. The deal comprises 141 new jets and follows a handshake deal between the two parties that was announced in July.
    The agreement pushes the cost of the F-35A conventional model — used by the U.S. Air Force and most foreign buyers — to $89.2 million per aircraft, a 5.4 percent reduction from the $94.3 million in the 10th batch of aircraft.
    Pentagon reaches handshake deal with Lockheed on newest batch of F-35s
    The Pentagon makes its biggest F-35 order yet.
    The more expensive “B” and “C” models incurred even bigger price cuts. The Marine Corps’ F-35B short-takeoff-and-vertical-landing variant’s cost decreased 5.7 percent from $122.4 million to $115.5 million, while the F-35C carrier variant dropped a whopping 11.1 percent from $121.2 million to $107.7 million per unit.
    Greg Ulmer, Lockheed’s F-35 vice president and general manager. “As production ramps up and we implement additional cost savings initiatives, we are on track to reduce the cost of the F-35A to $80 million by 2020, which is equal to or less than legacy aircraft, while providing a major leap in capability.”

    Reply
  32. US government just placed and order on 141 F35 jets. The price is the lowest it has ever been at 90 million for F35A. Projected to get to 80 million by 2030. Lockheed of course is making more of them to supply to other NATO members and Israel.

    Reply
  33. As an alternative idea to manned fighters, we might consider a large airframe carrying a megawatt class laser, or a powerful railgun or coilgun.

    Such an airplane will have the ability to attack targets from ground level to low earth orbit, and deliver effects at speeds far exceeding the ability of any target to escape.

    They may still need F-35’s to fly ahead and scout out targets in some scenarios.

    Reply
  34. I know… the “dopey bandwagon” seems to be hopped on at every level of civilization. Find something new, and keep name-dropping it into the conversation to sound current. I’m surprised they didn’t spring Quantum Computing and Blockchain for Greater reliability. Because, you know, those are hip (hop) words. GoatGuy

    Reply
  35. It is VERY unlikely that the “Seventh Generation” will be aircraft flying in excess of Mach 5. Several reasons work against such aircraft:

    • № 1: skin heating stealth
    • № 2: engine inflow heating
    • № 3: sharp edges stealth
    • № 4: need to be 20+ km flight path
    • № 5: lousy handling at speed

    There likely are more, but those are the basics.

    № 1: skin heating stealth → deep into the supersonic comes greater supersonic ‘berm’ and laminar turbulence heating. The super-stealth planes have soft, porous, electromagnetically resistive coatings to make them black in RADAR. These coatings tend not to do well when heated.

    № 2: engine inflow heating → SR–71 Blackbird found that above Mach 3.5 (the limit of the design) the inlet would compress the air where the front vanes of the jet engine compressor would overheat.

    Of course, at the CENTER of the ‘bird’ were 5 primary technologies:

    • A: The engine
    • B: The super-sharp skin
    • C: The inlet nacelles
    • D: The avionics
    • E: The leaky airframe

    The engine had to work with inlet compression up to 5 over ambient, with temperatures up to 700° C. This was extraordinary because in the engine, inlet gas had to be compressed far further, to get thrust at high supersonic velocities.

    The “shape of the plane” had to have very sharp edges, very swept wing surfaces, nothing at all “sticking out”. The very thinness of the skin required special bonding. It was a work of art.

    The inlet nacelles (air scoops) of the engines had to be maneuverable to “point into the airstream”. This was a major innovation which used the speed of the plane to compress the inlet stream BEFORE the engine. Where its heat could be dissipated safely.

    Avionics had to work at air pressures far below commercial service — or even military — were capable of. This in turn required hermetically sealed avionics with 5,000 meter interior pressure, and helium sa the working gas. Very costly. Very necessary. Very hard to repair.

    Then the whole airframe: nothing could be done about the substantial index-of-thermal-expansion of titanium, the ONLY metal at the time capable of taking the stresses, the heat, being light enough, and non-oxidative enough to survive Mach 3.5+. So much so that the plane literally “dripped fuel” on the tarmac. It tightened up on its own in flight because of heating.

    № 3: sharp edges stealth

    Can’t have much stealth with sharp edges. And shiny surfaces. And …

    № 4: need to be 20+ km flight path

    Well… that’s 65,000+ feet. The air is REAL thin up there. Less than 9% of sea level.

    № 5: lousy handling at speed

    See № 4. If you can’t “blow a bunch of air sideways”, you can’t get a 20+ ton aircraft to turn with the wind.

    Just saying,
    GoatGuy

    Reply

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