Yeah I agree that there’s a lot more going on than simple binary conditions. Ultimately you always have to look back to the requirements and performance parameters to really judge if a solution is being adopted as a reflection of greater or lesser capabilities. That said, there’s a reason why so many variable geometry designs went out of vogue, and I do think it’s worth noting the underlying reasons for that.
H-20 bomber (with H-X, JH-XX)
- Thread starter Deino
- Start date
So why haven’t more designs been adopted with other forms of variable geometry surfaces? Why did the YF-23 go with a pelican tail rather folding tails?
Certainly, though this is the entire reason why two pages ago I said this idea for H-20 having folding tails shouldn't be called "variable geometry" because it makes one think of traditional "variable geometry" (i.e.: swing wing) aircraft.
The manner in which I envision a potential configuration to work, those "variable geometry" tails would operate less much more similarly to weapons bay doors/landing gear doors rather than swing wings.
Obviously ultimately at the end of the day having less moving parts is better if you are able to achieve performance to a given standard, but if you aren't, then you'll need some moving parts.
Perhaps but I'm inclined to feel they wouldn't bother with something more costly, complex, less reliable, and unnecessary if it were truly unnecessary. Particularly when secondary observers don't have access to any details.
It's far more ridiculous to believe that not adding moving tails (again assuming the hypothetical) would be superior an option to doing so. Equally ridiculous would be believing that having moving tails indicates an inability to produce a set of FC that allows for old traditional flying wing. When we know that 1. China's got at least one flying wing aircraft in operation and flying for nearly 8 years if not much longer and 2. a moving tail that shifts to make the aircraft a flying wing really only adds complexity and ACHIEVES flying wing configuration. That's assumed but the idea makes me laugh.
And how does that prove your point? lol
Do you realise that YF-23 design is about 30 years old? The project outline possibly older? In an era where the best computing available doesn't even match your smartphone?
You're implying that variable geometry won't become a feature in future. It's an excellent engineering solution to potentially critical platform capabilities in at least a few airforces.
Look, my point is simple.
There is a reasonable basis to be skeptical to the idea that they may choose folding tails, and if they do not go for folding tails, then this basis would likely be the cause.
There is also a reasonable basis to entertain the idea that they may choose folding tails, and if they do go for folding tails, then this basis would likely be the cause.
And all of this discussion is at a stage where we don't know if H-20 will adopt folding tails or not, but also keeping in mind that at this stage the null hypothesis is slightly in favour of the idea of H-20 not having folding tails (simply due to the lack of consistent rumours mentioning folding tails over recent years).
To be fair to the YF-23, it could probably meet its RCS requirements for the ATF program without needing to have a "tailless" configuration that would "necessitate" folding tails.
I agree there is reason to be skeptical that a few non-official sources are claiming re folding/moving tails. Who's arguing that?
If they don't go for moving tails, it's possible this is one or sole reason.
If they do go with moving tails, it's quite possible that it was the best design given unknown tasks and capabilities the aircraft is required to achieve.
I wouldn't speculate on which is the null hypothesis because credibility and bias is going both ways. Those hints often do get a fair bit right. Particularly when it's about something relatively "unique". As in they don't make up outrageous stuff and provide depth of detail unless they know something or it's an intentionally placed red herring.
My whole point is that moving tails =/= inferior design and incapable FC. It could be the case but that's not evidence for it! That's an important piece of logic I feel needed to be pointed out as this thread is beginning to talk about folding tails as if it were either an overall compromise or indicative of inability to handle a flying wing bomber FC which I suspect is not the case considering how flying wing FC design has been done by China for about a decade if not longer and the differences in aircraft (although major) represent smaller engineering problems in balance and mechanical stability. Even then, huge differences to what's already been done can be resolved just with FC.
I suspect that IF these hints are accurate about moving tails, the likely reason/s have something to do with managing risks. In particular risks inherent to flying wing designs in take off and landing.
If the moving tails is the case, we don't know if they can be shifted into a position that aligns with the wing or not. So IF moving tails is the case, it could still be a flying wing or would have some non-aligned stabiliser/tail.
The range of reasons span everything from trying to manage risk of take off and landing, to requiring this less than ideal moving/fixed control surface because they can't build a strategic bomber aircraft in pure flying wing configuration, presumably because FC is a problem. I doubt the latter very much.
For variable geometry. It's a tool in the toolbox. No one has magic gravity bending propulsion (that we know of). Variable geometry is a great option to have than to completely ignore no matter what the question is. Depending on how cleverly it can be incorporated and where available technology is such as hydraulics and miniaturised mechanisms for facilitating serious variable geometry, it isn't impossible that it becomes a major feature in future generation aircraft. An airframe that changes depending on flight parameters and required performance is one solution to "aerodynamic design and control laws" and not because those departments are lacking. If anything those departments need to be extra competent to pull it off.
If the moving tails is the case, we don't know if they can be shifted into a position that aligns with the wing or not. So IF moving tails is the case, it could still be a flying wing or would have some non-aligned stabiliser/tail.
The range of reasons span everything from trying to manage risk of take off and landing, to requiring this less than ideal moving/fixed control surface because they can't build a strategic bomber aircraft in pure flying wing configuration, presumably because FC is a problem. I doubt the latter very much.
For variable geometry. It's a tool in the toolbox. No one has magic gravity bending propulsion (that we know of). Variable geometry is a great option to have than to completely ignore no matter what the question is. Depending on how cleverly it can be incorporated and where available technology is such as hydraulics and miniaturised mechanisms for facilitating serious variable geometry, it isn't impossible that it becomes a major feature in future generation aircraft. An airframe that changes depending on flight parameters and required performance is one solution to "aerodynamic design and control laws" and not because those departments are lacking. If anything those departments need to be extra competent to pull it off.
I'm not only talking about sources, but about the capability and technical tradeoffs of choosing to go for moving tails or not.
If they don't go for moving tails, I imagine there is a good of a technical reason for why they are not.
Equally, if they do go for moving tails, I imagine there is a good technical reason for why they are.
I don't care about whether moving tails is or is not reflective of good or bad design or sufficiently capable flight control or not.