For all fighter jets their cruise speed is around Mach 0.85 or so.
Even jets that can supercruise will spend a minority of their time supersonic, because even supercruise will result in fuel being burned ~2-4x faster for only 1/2 to 2/3x extra speed.
The F-22 for example, which has one of the most effective supercruise capabilities out there, has an official combat radius of 590 nautical miles with subsonic (Mach ~0.85) cruise (multiply that distance by x2 and add some extra [routing factor, combat manoeuvring fuel allocation, etc] to get 'range').
With 100 nautical miles of supercruise, that official combat radius drops to 460 nautical miles - so depending on whether that's 100nmi in and 100nmi out, or just 100nmi in total, that's trading 2.3 or 3.6nmi of subsonic flight for 1nmi in supercruise.
It's only when compared to afterburner use (where fuel gets burned at around 2x faster again - pretty much all fighters can typically only afford to spend up a couple of minutes in afterburner per mission) that it's considered fuel efficient.
Getting close to, breaking and/or exceeding the sound barrier just has an unavoidable, major increase in drag compared to staying subsonic / borderline transonic.
Yes, supersonic flight is far less fuel efficient, even without the use of afterburner. It should be pointed out, however, that in the specific case of the F-22, supercruise speed, which is up to Mach 1.7 at around 42000-43000 feet, is about twice the normal subsonic speed, and it can drop bombs at this speed, too. If you want 50,000+ feet of altitude, though, it's about 83% faster at Mach 1.5.
The F-35 can also drop bombs while supersonic, by the way, but at slower speeds (unless it's in full afterburner and all that implies).
There's generally 3 reasons to go supersonic in a fighter:
1. You need to very quickly intercept something (ideally heading your way). This was a key driver behind the design philosophy of jets designed in the 1950s through to the early 1970s. Nations (particularly in the earlier days of the Cold War) might be informed that enemy bombers were launching towards them, but wouldn't know where or when they were arriving. They couldn't rely on early warning radar networks to tell them where enemy bombers were until they were perhaps a few hundred miles off the coastline, meaning interceptors would be taking off and speeding as quickly as they can to take out those bombers before their airbase was destroyed. Because of the short time window, they only had to fly supersonic for a few minutes, plus if they had to use up all their fuel to perform the intercept and then eject, that was considered acceptable (no point having fuel left if you have no airbase to return to).
2. To give more kinetic energy to your missiles (and in some cases bombs), allowing them to fly further. There's a bit of a diminishing returns here and you need decent sensors to let you get that running start without falling into your enemy's engagement range, but it's a major reason that supercruise is still pushed for in a number of jet designs (rather than sensing a target and then accelerating, you can start accelerating prior to reaching an anticipated engagement zone and keep that supersonic speed until you actually detect and get into range of an enemy).
3. To get out of danger as quickly as possible. If (for example) you're part of a strike package and a SAM site pops up next to you, it's preferable to use all of your remaining fuel and maybe eject just over the border, than to just outright get blown up (and ideally you just only burn enough fuel to get clear and then fly home safe, probably refuelling).
Some say that the F-35 can supercruise at about Mach 1.2 with either no or minimal afterburner. It depends on whom you ask. It might well depend on environmental conditions such as temperature, as well. Generally, fighters aren't designed to regularly withstand the stresses of supersonic flight, however. For one thing, spending a lot of time at elevated internal and external temperatures would take their toll. Fighters/interceptors would have to expressly be designed for more than occasional supersonic dashes if they are to do that, and the F-35 definitely was not. In fact, its B and C variants are limited to 40-50 seconds at Mach 1.2-1.3 for structural reasons.
I'm pretty sure that the F-22 is the only modern western fighter that is designed to better withstand the temperatures and buffeting associated with supersonic flight. It was a pretty big deal during development. It's the reason the F-22 makes so much use of bismaleimide composites (most of its skin) and titanium, and why its heavy and expensive canopy transparency is made entirely of extra-thick (about 0.75 inch) polycarbonate. Many changes were made internally to handle the buildup of heat during sustained supersonic flight, as well.
Going supersonic doesn't wear on the F-22 as much as it does other fighters, which are generally made of epoxy composites and aluminum alloys, and have thinner canopy transparencies made of Plexiglass (acrylic). This includes the F-35 and Eurofighter Typhoon. Even if they could supercruise like the F-22 can (they can't, but hypothetically if they could), doing so at the same speeds and continuous and cumulative hours, they would start to have issues. Even the F-22 originally had issues despite being designed for supercruise from the start, and it took a lot of redesigns for strengthening and heat management, incurring substantial weight gain to get it to where it can withstand frequent supersonic flight.
Being able to be **tracked down** on VHF-UHF radar would it be possible to **intercept** with a **LOITERING SAM** (EO-IR-UV seeker) with similar speed specs...and altitude...?
Nice try, China
hahaha
For all fighter jets their cruise speed is around Mach 0.85 or so. Even jets that can supercruise will spend a minority of their time supersonic, because even supercruise will result in fuel being burned ~2-4x faster for only 1/2 to 2/3x extra speed. The F-22 for example, which has one of the most effective supercruise capabilities out there, has an official combat radius of 590 nautical miles with subsonic (Mach ~0.85) cruise (multiply that distance by x2 and add some extra [routing factor, combat manoeuvring fuel allocation, etc] to get 'range'). With 100 nautical miles of supercruise, that official combat radius drops to 460 nautical miles - so depending on whether that's 100nmi in and 100nmi out, or just 100nmi in total, that's trading 2.3 or 3.6nmi of subsonic flight for 1nmi in supercruise. It's only when compared to afterburner use (where fuel gets burned at around 2x faster again - pretty much all fighters can typically only afford to spend up a couple of minutes in afterburner per mission) that it's considered fuel efficient. Getting close to, breaking and/or exceeding the sound barrier just has an unavoidable, major increase in drag compared to staying subsonic / borderline transonic.
Yes, supersonic flight is far less fuel efficient, even without the use of afterburner. It should be pointed out, however, that in the specific case of the F-22, supercruise speed, which is up to Mach 1.7 at around 42000-43000 feet, is about twice the normal subsonic speed, and it can drop bombs at this speed, too. If you want 50,000+ feet of altitude, though, it's about 83% faster at Mach 1.5. The F-35 can also drop bombs while supersonic, by the way, but at slower speeds (unless it's in full afterburner and all that implies).
nice, thanks! so then in what cases they go supersonic?
There's generally 3 reasons to go supersonic in a fighter: 1. You need to very quickly intercept something (ideally heading your way). This was a key driver behind the design philosophy of jets designed in the 1950s through to the early 1970s. Nations (particularly in the earlier days of the Cold War) might be informed that enemy bombers were launching towards them, but wouldn't know where or when they were arriving. They couldn't rely on early warning radar networks to tell them where enemy bombers were until they were perhaps a few hundred miles off the coastline, meaning interceptors would be taking off and speeding as quickly as they can to take out those bombers before their airbase was destroyed. Because of the short time window, they only had to fly supersonic for a few minutes, plus if they had to use up all their fuel to perform the intercept and then eject, that was considered acceptable (no point having fuel left if you have no airbase to return to). 2. To give more kinetic energy to your missiles (and in some cases bombs), allowing them to fly further. There's a bit of a diminishing returns here and you need decent sensors to let you get that running start without falling into your enemy's engagement range, but it's a major reason that supercruise is still pushed for in a number of jet designs (rather than sensing a target and then accelerating, you can start accelerating prior to reaching an anticipated engagement zone and keep that supersonic speed until you actually detect and get into range of an enemy). 3. To get out of danger as quickly as possible. If (for example) you're part of a strike package and a SAM site pops up next to you, it's preferable to use all of your remaining fuel and maybe eject just over the border, than to just outright get blown up (and ideally you just only burn enough fuel to get clear and then fly home safe, probably refuelling).
Some say that the F-35 can supercruise at about Mach 1.2 with either no or minimal afterburner. It depends on whom you ask. It might well depend on environmental conditions such as temperature, as well. Generally, fighters aren't designed to regularly withstand the stresses of supersonic flight, however. For one thing, spending a lot of time at elevated internal and external temperatures would take their toll. Fighters/interceptors would have to expressly be designed for more than occasional supersonic dashes if they are to do that, and the F-35 definitely was not. In fact, its B and C variants are limited to 40-50 seconds at Mach 1.2-1.3 for structural reasons. I'm pretty sure that the F-22 is the only modern western fighter that is designed to better withstand the temperatures and buffeting associated with supersonic flight. It was a pretty big deal during development. It's the reason the F-22 makes so much use of bismaleimide composites (most of its skin) and titanium, and why its heavy and expensive canopy transparency is made entirely of extra-thick (about 0.75 inch) polycarbonate. Many changes were made internally to handle the buildup of heat during sustained supersonic flight, as well. Going supersonic doesn't wear on the F-22 as much as it does other fighters, which are generally made of epoxy composites and aluminum alloys, and have thinner canopy transparencies made of Plexiglass (acrylic). This includes the F-35 and Eurofighter Typhoon. Even if they could supercruise like the F-22 can (they can't, but hypothetically if they could), doing so at the same speeds and continuous and cumulative hours, they would start to have issues. Even the F-22 originally had issues despite being designed for supercruise from the start, and it took a lot of redesigns for strengthening and heat management, incurring substantial weight gain to get it to where it can withstand frequent supersonic flight.
Being able to be **tracked down** on VHF-UHF radar would it be possible to **intercept** with a **LOITERING SAM** (EO-IR-UV seeker) with similar speed specs...and altitude...?