totoroCylinder for the fuselage made out of one piece carbon fibre doesn’t need to be the only way to go. I’m not gonna say that either is better but both approaches have something positive in them.
Take a metal barrel. cylindrical, smooth, simple walls. Put it under pressure from all sides. at certain pressure, it will buckle. How do you prevent that? You can either make walls thicker/heavier OR:
If you make bends in the metal sheet before you wrap it around and make it into barrel shape – you will be able to witstand more pressure, with just a bit more material used. Your typical fuel barrel is made just like that, with those ring shaped bumps going around the barrel.
Now, if you put a truss structure inside the barrel, keeping the outer sheet of metal, you will have even more support, meaning you will be able to afford even less thickness/weight of the outer sheet. Yes, there will be added weight of truss structure itself, but one simply can’t beat a good truss for rigidity.
What I am trying to say is that for all the added weight of support structure and rivets/glue of airbus approach, it will have benefit of thinner/lighter walls. Of course, it’s very hard to tell just which approach is going to be better, but whichever it is, i highly doubt it will have a significant margin of weight savings to it. With added other system weights, aerodynamics savings, manufacture costs, all the other costs, i just don’t see either boing or airbus being any better or worse of because of their approach to fuselage construction.
totoroSure, they could ram, but there’s just not enough space on that small bomb to use it in effective way. To work properly against specific wavelengths of SAM radar, it needs a certain thickness to it. While there’s still enough space to use RAM against some very small wavelengths, i fear that would lower available internal space to perhaps just two dozen pounds of explosive. Also, depending on strength of the material, maybe wing are other thin parts simply could not be made out of RAM. Lots of IFs in that business.
totoroThat is a cool thing. I shall just use this opportunity to preempt any possible claims of ‘oh, maybe it will be stealthier too!’ with a ‘go check electrical conductivity levels of carbon fibre’. Composite materials can help with radar stealth but carbon fibre is not the best way to go about it. Cheers 🙂
totoroBecause the nature of close air support is changing. Sure, in today’s iraq and afghanistan, where the usual threat is a dude with ak47 with only a smatter of shoulder launched sams, whizzing over the battlefield at low altitude and gunning everything down is doable, even cost effective.
But lets imagine a real war. where close air support is called against a potent opponent who still has a decent AAA and SAM ability on the field, accompanying its forces. Imagine various CLAWS, tuguskas, Tor1m, etc all datalinked and sharing information. such a force alone could prevent any attacking airplane from ever using a gun.
That is why jsf is meant to replace a-10. Sure, a-10 is going through refurbishment program and will remain in service until jsf gets fielded in enough numbers – but it will happen. Actually, I would say even the future of helicopter gunships is bleaker today than it was just 15-20 years ago. Apache may very well be the last of its kind, for US at least. Instead of such platforms, proliferation of uavs with powerful sensors which will direct guided artillery rounds and various projectiles launched from jsf class of planes is the way to go.
totoroIt is all a matter of tradeoffs. Do you:
A) employ rotating array inside a dome and get fairly decent size array (imporant for resolution, range, available wavelengths…) that will not get you 360 coverage all the time since array rotates and always has short blind spots.
B) use a set of phased arrays that give you 360 coverage but at the cost of making each of them relatively smaller than the array in A) with all that comes with that…
C) or C, use the biggest possible array, so big in fact that you can only have it facing just two sides and by default you have to have blind spots that you then work around with steering the plane.
It all depends on what is important. I would actually say that beam concept is better for long range detection, though if the plane is alone and enemy fighters are approaching , i’d feel safer in a B) kind of awacs.
totoroAny sub running on batteries will be rather damn quiet, especially at lower prop speeds, even old Ming class, let alone a Song. Question here is how fast the carrier group was going. It couldn’t have been going over 20 kts as the sub can’t go any faster than that. Even if it was going, around, say, 15 kts, battery endurance at that speed would be very miniscule, enough for some 10-15 mins. In that regard, it’d be very hard to actually shadow a carrier group in any kind of war conditions where the carrier group would almost certainly not crawl around at 5 kts.
What sounds more plausible is carrier group steaming faster, producing more noise, enemy sub picking up that noise and trying to intercept the carrier group while itself going fairly slowly and silently. Of course, that requires lots of luck to be at the right place at the right time to begin with.
Bottom line is – article is nothing suprising. subs running on batteries are quiet and sea is a fidgety thing. If only relies only on passive sonar, a sub could theoretically get to few miles away without being detected – there are no guarantees with passive sonar detection.
totoroWhy haven’t they been using the conformal fuel tanks if those have been purchased? Seems like a more aerodynamically efficient way to cram all that extra fuel instead of using 5 drop tanks of various sizes.
totoroUnless they’re in geosync orbits over china, 12 satellites are not enough to provide contiuous coverage for chinese at usual altitudes. Only if orbiting at much higer altitudes could 12 be enough to cover entire globe.
totoroNot to mention that stated ranges of various missiles are purposefully innacurate. Amraam ranges have been understated for some time and they keep being addressed in vague terms. No one aam maker or air force that uses it is going to come out and give you (us) even remotely accurate data. Guesstimation is the name of the game here and it’s the only way to go, really.
totoroConcepts are notoriously hard to litigate for/against when it comes to IP rights. The broader the concept, the harder it is. Since blended wing is something that’s been around for decades as a concept, (plus prototypes during ww2) it in itself is impossible to claim as one’s own and protect. Have the technologies like turbofan engines or fly by wire etc been protected? And they’re more specific than blended wing body. By that logic no one should have been able to make an airliner like 707 or 737, yet we have their ‘blatant ripoffs’ flying everywhere.
totoroThese are just some of the things that determine radar range, they’re by no means all equally important nor are they listed by importance here:
emitter power
array gain
area of the array
length of emitted pulse
turn rate of the receiver (for mechanically scanned arrays)
wavelength at which radar operates
time between emitted pulses
On top of that, received signals can be made more useful by better computer processing and filtration of various background clutter. In wartime enviroment one also needs to add jamming resistance (again dependant various things)
There’s also RCS of given target and its important to remember wavelength is already calculated into that, so a plane actually has many different RCS values for many different wavelengths. Of course, RCS depends on much more than just wavelength of incoming radar signal.
totoroYes, it includes the whole plane from tip to toe. Without it, its something around 14.5 m long, perhaps even a bit less.
totoroSo what are all those pics of mock up cockpits? There are 3 differnt ones there, haven’t seen any of them before. If i had to choose, the third one, darkest looking one, would be my j-10 cockpit pick. Not bad. Nice to see a wide angle HUD, too, unlike that narrow thing on FC1. First and second pic are a mystery to me…second one is too blurry to tell much really…but first one is totally weird. Judging by everythign, especially the made up scheme of twin tail & canard plane on one screen, first pic is of some concept cockpit.
totoroI think they have negotiated a multi year procurment so that it is open till 2011
I think in the end the congress had none of that, and budget for 2007 has envisioned money for 20 raptors, which falls in line with 60 more in three years, with 2009 being last year. Of course, they are still hoping jsf will be late and thus (somehow) they will convince congress to get more money for additional raptors. I actually wouldnt be surprised if jsf gets delayed intentionally by some sort of internal USAAF/LM games, in order to squeeze out 20-30 more raptors.
totoroOkay, but wouldn’t you test a weapon on a platform you plan to integrate it on? And if so, wouldn’t j8 be the last plane in PLAAF inventory to do that, save for j7? Any of the following seem better suited for the role: jh7, j11, j10, Q5. Hell, even fc-1 would be better if it was available for such tests.
If one wants to test max range achieved at max speed, j11 and j10 are just as good if not better for that role. Especially considering both j10 and j11b are said to be have a multirole future.
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