3 ms·

>Where they lag behind isn't range or power no. The Russian and Chinese planes with those engines can't supercruise. Thus they either use afterburner - short r

by trhway 6y ago

>Where they lag behind isn't range or power no. The Russian and Chinese planes with those engines can't supercruise. Thus they either use afterburner - short range - or go slow. >, but (maybe for the J20) in stealth. exactly - the engine for stealth plane needs to be stealth itself. That means a bunch of technical solutions and limitations (like hiding the turbine from the radars looking from behind the plane, lowering IR signature, etc.) which complicates the engine construction and may clash with for example the power requirements to supercruise.

sudosysgen 6y ago
>no. The Russian and Chinese planes with those engines can't supercruise. Thus they either use afterburner - short range - or go slow. The WS-10C engines for the J20 are of equal power to the F119 engines of the F22. They cannot supercruise indeed, yes, but neither can the F35. The J20 is however larger and less aerodynamic and the engine probably has different trans-sonic characteristics and thus cannot supercruise despite being as powerful as the F22. >exactly - the engine for stealth plane needs to be stealth itself. That means a bunch of technical solutions and limitations (like hiding the turbine from the radars looking from behind the plane, lowering IR signature, etc.) which complicates the engine construction and may clash with for example the power requirements to supercruise. There is no rear-aspect stealth for any aircraft. The F22 has a 20-25dB higher RCS from the rear than the front, enough to make it plainly detectable. The same will be for any airplane, including the J20 that seems to have a similar drop in RCS from the rear. As for IR signature, this is simply not known. Modern IR sensors can already detect heat emissions from air friction, and lock onto planes even with their engines fully turned off.
- trhway 6y ago
  >They cannot supercruise indeed, yes, but neither can the F35. F35 is able to supercruise at 1.2 M. The issue is that its stealth coating gets damaged. >There is no rear-aspect stealth for any aircraft. The F22 has a 20-25dB higher RCS from the rear than the front, enough to make it plainly detectable. The same will be for any airplane Not the same for any. While the rear aspect situation is naturally worse, it is still very different for "normal" vs. stealth airplanes - i.e. distances at which it can be detected and how well a missile can lock are still significantly decreased by stealth measures like those for F22 and F35 for example : https://en.wikipedia.org/wiki/Pratt_%26_Whitney_F135#Design https://en.wikipedia.org/wiki/Pratt_%26_Whitney_F135#Design "Like the F119, the F135 has a stealthy augmentor where traditional spray bars and flameholders are replaced by thick curved vanes coated with ceramic radar-absorbent materials (RAM). Afterburner fuel injectors are integrated into these vanes, which block line-of-sight of the turbines, contributing to aft-sector stealth. "
  - sudosysgen 6y ago
    From the RCS curves I find, it's 20-25dB for both planes in augmentation in the rear aspect. Enough for the F22 to simply not be stealthy from the rear. As for the F35 supercruise, this is simply wrong. The engine overheats without the afterburner at supersonic speeds and thus supercruise cannot be done for more than a few seconds. Afterburners must be used, but the afterburners in turn damage the RAM. The RAM in the F35 is not actually destroyed by air friction. It's destroyed by the afterburners : https://www.defenseworld.net/news/26992/Swiss_Internal_Report_Flags_F_35_Afterburner_Issue https://www.defenseworld.net/news/26992/Swiss_Internal_Repor... From this one concluded that the F35 cannot sustain Mach 1.2 without using afterburners. This is actually even worse than not being able to supercruise - it cannot sustain supersonic flight, full stop.

by trhway 6y ago

sudosysgen 6y ago

>no. The Russian and Chinese planes with those engines can't supercruise. Thus they either use afterburner - short range - or go slow. The WS-10C engines for the J20 are of equal power to the F119 engines of the F22. They cannot supercruise indeed, yes, but neither can the F35. The J20 is however larger and less aerodynamic and the engine probably has different trans-sonic characteristics and thus cannot supercruise despite being as powerful as the F22. >exactly - the engine for stealth plane needs to be stealth itself. That means a bunch of technical solutions and limitations (like hiding the turbine from the radars looking from behind the plane, lowering IR signature, etc.) which complicates the engine construction and may clash with for example the power requirements to supercruise. There is no rear-aspect stealth for any aircraft. The F22 has a 20-25dB higher RCS from the rear than the front, enough to make it plainly detectable. The same will be for any airplane, including the J20 that seems to have a similar drop in RCS from the rear. As for IR signature, this is simply not known. Modern IR sensors can already detect heat emissions from air friction, and lock onto planes even with their engines fully turned off.

trhway 6y ago
>They cannot supercruise indeed, yes, but neither can the F35. F35 is able to supercruise at 1.2 M. The issue is that its stealth coating gets damaged. >There is no rear-aspect stealth for any aircraft. The F22 has a 20-25dB higher RCS from the rear than the front, enough to make it plainly detectable. The same will be for any airplane Not the same for any. While the rear aspect situation is naturally worse, it is still very different for "normal" vs. stealth airplanes - i.e. distances at which it can be detected and how well a missile can lock are still significantly decreased by stealth measures like those for F22 and F35 for example : https://en.wikipedia.org/wiki/Pratt_%26_Whitney_F135#Design https://en.wikipedia.org/wiki/Pratt_%26_Whitney_F135#Design "Like the F119, the F135 has a stealthy augmentor where traditional spray bars and flameholders are replaced by thick curved vanes coated with ceramic radar-absorbent materials (RAM). Afterburner fuel injectors are integrated into these vanes, which block line-of-sight of the turbines, contributing to aft-sector stealth. "
- sudosysgen 6y ago
  From the RCS curves I find, it's 20-25dB for both planes in augmentation in the rear aspect. Enough for the F22 to simply not be stealthy from the rear. As for the F35 supercruise, this is simply wrong. The engine overheats without the afterburner at supersonic speeds and thus supercruise cannot be done for more than a few seconds. Afterburners must be used, but the afterburners in turn damage the RAM. The RAM in the F35 is not actually destroyed by air friction. It's destroyed by the afterburners : https://www.defenseworld.net/news/26992/Swiss_Internal_Report_Flags_F_35_Afterburner_Issue https://www.defenseworld.net/news/26992/Swiss_Internal_Repor... From this one concluded that the F35 cannot sustain Mach 1.2 without using afterburners. This is actually even worse than not being able to supercruise - it cannot sustain supersonic flight, full stop.