Discussion
Not quite. It's much smaller, with about 1/2 the bomb load and far cheaper but, with more modern Low Observable build techniques & materials than the B2, I'd say it was stealthier.
Whilst the techniques/materials for being "anti-Radar" is well known by now, I'm still not sure what they're doing about being harder to spot against IRST sensors which are getting better and better all the time. They've had cold blown engine exhausts for a while but modern sensors can now pick up leading edge heat from quite a surprising range.
Whilst the techniques/materials for being "anti-Radar" is well known by now, I'm still not sure what they're doing about being harder to spot against IRST sensors which are getting better and better all the time. They've had cold blown engine exhausts for a while but modern sensors can now pick up leading edge heat from quite a surprising range.
heisthegaffer said:
I was reading up on this, it's been designed to be far more suited for upgrades so offer a longer service life at a cheaper cost too. In theory.
Also, they plan on buying 100 of them which a lot to me but will replace both the B1 and B2.
Economies of scale help too. With the F35, the price continued to drop per unit, the more they bought, will be the same with the B21Also, they plan on buying 100 of them which a lot to me but will replace both the B1 and B2.
IanH755 said:
Not quite. It's much smaller, with about 1/2 the bomb load and far cheaper but, with more modern Low Observable build techniques & materials than the B2, I'd say it was stealthier.
Whilst the techniques/materials for being "anti-Radar" is well known by now, I'm still not sure what they're doing about being harder to spot against IRST sensors which are getting better and better all the time. They've had cold blown engine exhausts for a while but modern sensors can now pick up leading edge heat from quite a surprising range.
Can they use the jet fuel as a coolant for the leading edge? Or would this be too complex/ cause issues for the engines? You need to make the aircraft match the infrared background as much as possible. Whilst the techniques/materials for being "anti-Radar" is well known by now, I'm still not sure what they're doing about being harder to spot against IRST sensors which are getting better and better all the time. They've had cold blown engine exhausts for a while but modern sensors can now pick up leading edge heat from quite a surprising range.
Junior Bianno said:
lost in espace said:
Trevatanus said:
Economies of scale help too. With the F35, the price continued to drop per unit, the more they bought, will be the same with the B21
Wow $600 million each. 46and2 said:
Can they use the jet fuel as a coolant for the leading edge? Or would this be too complex/ cause issues for the engines? You need to make the aircraft match the infrared background as much as possible.
The leading edge tends to be slats which move so don't lend themselves to incorporating plumbing.Maybe diffusing cold air from an early enginevcompressor would be easier, it's air and it's only going one way.
The B2 didn't use any Leading Edge moving surface systems so I'm not sure if the B21 will either.
The issue with using fuel to cool the leading edge is that jet fuel needs to be warm (IIRC 50-70'c) to get the most amount of energy from it, so using to cool the leading edges down to -30'c or lower to match the ambient air at altitude will mean you have to pull that fuel back into a heating section of the Environmental Control System to be reheated which means more pipes, more components, more weight, more cost and more points of failure etc.
There could be an option of using cooled & conditioned bleed air but again its extra pipes, valves, weight & cost etc. Whatever is finally used to "defeat" modern IRST (maybe not in the B21) will just start another "stealth vs radar" style Arms race between the different design teams.
The issue with using fuel to cool the leading edge is that jet fuel needs to be warm (IIRC 50-70'c) to get the most amount of energy from it, so using to cool the leading edges down to -30'c or lower to match the ambient air at altitude will mean you have to pull that fuel back into a heating section of the Environmental Control System to be reheated which means more pipes, more components, more weight, more cost and more points of failure etc.
There could be an option of using cooled & conditioned bleed air but again its extra pipes, valves, weight & cost etc. Whatever is finally used to "defeat" modern IRST (maybe not in the B21) will just start another "stealth vs radar" style Arms race between the different design teams.
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