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kilcoo316

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Viewing 15 posts - 481 through 495 (of 721 total)
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  • kilcoo316
    Participant

    At the end of the day, taking direct action (military) would probably result in more casualties than leaving them alone.

    I don’t believe that nuclear weapons will ever be used again – while a maniac {like hitler for instance} might demand their use, I believe the military leaders would step in and say no.

    There is bound to be some sanity there…. isn’t there?

    in reply to: Report:N.Korea performed first-ever nuke test-What's next? #2551330
    kilcoo316
    Participant

    What next?

    Nothing…. there are no prospective oil contracts for Halliburton in North Korea :rolleyes:

    As usual the entire west will stay out of this one, and let the locals sort it out since no “strategic interests” are threatened.

    in reply to: F-22 Doing A Cobra Maneuver #2553242
    kilcoo316
    Participant

    Lots of aircraft use elevons. The thing that makes the F-22 and F-35 (and possibly others) different is they use everything.

    Coupling all the control surfaces together is not that challenging (comparatively).

    The F-22 is using the ailerons/flaps to move the wing aero centre back – it adds a little to the elevator input, but compared to TVC and the elevators, its very small.

    It would make a bigger difference in supersonic manouvering though.

    But other aircraft like the Rafale and EF2000 would not need to do this, the canards would provide all the control authority that the airframe could take.

    in reply to: F-22 Doing A Cobra Maneuver #2553248
    kilcoo316
    Participant

    Versatility, reliability and cost effectiveness.

    Avionics, Engines/avionics & fair enough.

    Besides, how versatile is a ****ty couple hundred mile radius?

    Speaking purely of the airframe, no avionics, no engines – its crap.

    in reply to: Yet More A380 Delays (Merged) #524059
    kilcoo316
    Participant

    I’m not too worried.

    The wiring issue is just a thing that will take time to put right.

    Apparently the aircraft performance itself is better than expected – now if it had been worse, then Airbus would have reason to sh!t themselves. While the airlines may cry and complain, they’ll not jump as the B747-8 simply isn’t as cheap to run as the A380, and thats the bottom line.

    in reply to: F-22 Doing A Cobra Maneuver #2553486
    kilcoo316
    Participant

    Doesnt the SH also have this ? instead of a dedicated air brake !!

    You mean the vertical fins both deflecting inboard to form an airbrake?

    The A, B, C & D hornets had it too.

    As a result of their inept design [which really should never have been let near service], the hornet doesn’t have enough elevator control to pitch up on take-off, so the two rudders have to deflect inboard to induce further nose up pitching to get the damn thing off the carrier deck right.

    http://www.xp-office.de/F-18/Bilder/us-navy-f18_jpg.jpg

    It really is hard to fathom why the Navy decided to utilise such a singularly useless airframe.

    in reply to: Static test B-2s #2553492
    kilcoo316
    Participant

    They might have kept it for R&D work.

    Especially considering it looks like the B-2A will form the basis of the USAF’s next bomber – basically a cheaper B-2B with more munitions.

    in reply to: F-22 Doing A Cobra Maneuver #2553495
    kilcoo316
    Participant

    The F-22 doesn’t have elevators in the conventional sense, the rear horizontal tailsurfaces are elevons – they both perform the elevator and assist in the aileron roles. When an F-22 is banking, you will often see one “elevator” point up and the other down – same as the corresponding ailerons.

    Oh, and you don’t need a powerful computer for FBW, the F-22 having a better CPU makes bog all difference. The CPU is there to combine the various sensor feedbacks into one coherent picture.

    in reply to: F-22 Doing A Cobra Maneuver #2553531
    kilcoo316
    Participant

    The F22’s wing is called a delta wing…a delta wing is defined by an aerodynamicists as a wing with the presence of 3D flow rather than the typical 2D flow. The Su27’s main wing has 2D flow. If you understand that then you understand what a vortex is. The chin of the F22 is to generate the required vortex flow at high AoAs with the minimal amount of wetted area and weight. In fact the vortex flow from the chin acts as a virtual surface when coupled with the tail….which requires a very advanced flight control system. Give you a clue, the vortices coming off the chin and the highly swept chin are not steady! That’s how you can use it as a “virtual” surface.

    The reason the engine stays on the MKI is because routine supersonic TVC manuevering is out of the question on the MKI.

    I don’t think you understand my example of the advanced flight controls on the F22, or maybe i’m just not explaining it correctly. Sure, controlling multiple surfaces are not “advanced”, but what’s advanced is the coupling of all the surfaces to generate a high fidelity control in the spatial and temporal space. Ever wonder why the “pointability” of the F22 at high AoA is constantly mentioned…infact even the F2 and the F18E/F. That’s just one small part.

    As to the F22, it’s a newer type of vortex dynamics using the chins. Much earlier aircraft also used this (so it’s not totally new in terms of there’s just happens to be vortices coming off of these thing that actually annoyed Kelly Johnson for a while), but it’s compatibility with LO may be too simplistic a reason. It is tailored also for “vortex dynamics”. In fact it minimized the use of wetted area to generate the same vortices at high AoA and at the same time stabilized the nose to reduce yaw instabilities.

    The chin design is the way it is for stability in yaw and the demands of the LO department. Its mainly the nacelle forebody produces the vortices for extra lift – there was a problem with these vortices dynamically loading the ‘vertical’ fins, but its sussed now. You don’t want a big flat side ahead of the cg for yaw stability – obviously it will tend to push the nose around increasing yaw angle whereas you want it to the opposite. Siting the vertical fins was a large issue for this as well, and compromises between LO, high AoA yaw authority and low speed yaw authority had to be made. With the tails mounted at the back the aircraft was totally unpredictable through the AoA range – giving the fly-by-wire crew kittens. Moving the fins forward made the instability consistent in direction across alpha – making FBW programming much easier.

    The OVT has the controls all integrated as far as I was aware. The MiG 1.44/1.42 was the same. Dunno about the Rafale, EF2000, Su-33/Su-30/Su-35 etc etc, but I’d be shocked if it wasn’t the same. Its quite easy to do with the electronics.

    Its all about the low observables for the chin. They forced it to be the way it is [well, with input from stability and control for the design].

    in reply to: F-22 Doing A Cobra Maneuver #2553545
    kilcoo316
    Participant

    Point by point i can tell you that you are simply wrong from the aerodynamicists perspective.

    * The wing of the F22 is curved along the spanwise direction, reflecting a tailoring toward supersonic speeds by controlling the separated vortex in conjunction with the leading edge flaps. The Su27 is a simple tapered moderately swept wing. The F22’s wing is not only over a generation ahead of the baseline Su27, but a fully one generation ahead of the coupled canard/delta design (ie. the Rafale, Typhoon, and later Su27x. In fact this wing is so advanced (therefore so expensive), it wasn’t repeated in the lower cost F35. Although the X32 had a very advanced supersonic wing also.

    * In terms of aerodynamics, the F22 does have a triplane like aerodynamics, except that the forward fuselage strake is aerodynamically more efficient than an explicit canard as found in the Su27 triplane derivatives.

    * Instead of the 2D supersonic inlets (which traces back to the Vigilante if not earlier), the F22 has a 2-1/2D inlet where the cross flow situation is taken into acount.

    * The fly by wire system of the F22 is the most advanced in the world where it take into acount of integrated flight manuevering using all the surfaces. Basically, instead of decoupled effectors (i.e., let’s use only rudders to generate yaw), all the control surfaces participate in flight manuevers. The only other known aircraft to have near this level of advanced flight control is the Japanese F2 (unfortunately, their avionics was claimed to be crap by some here).

    * The aeroelasticity of the F22 takes into account the thrust vectoring requirements, making this the first and ONLY operational fighter plane out there designed with TVC in mind, instead of just add ons. If you claim it’s simply an add-on then you have absolutely no idea what it takes. A simple clue is why the YF22’s PIO accident caused such a pain to the firefighters. Just exactly which requirement that’s such a big deal? Supersonic TVC manuevering as part of routine. Just about every fighter plane can have a TVC upgrade, but most, if not all, won’t survive the way F22 uses it. Why is it so important how the F22 uses it? TVC has two distinct flight manuevering advantages. One at low speed and one at high speed (at intermediate speeds, high subsonics, it’s actually not as good as aero control surfaces). At low speeds it’s quite obvious, wings stall. At high speeds…the servo mechanisms for the aero surfaces became too weak. This also requires a high stiffness body mount for TVC operations. The way the Su27xx mounts it, the entire rear fuselage would buckle.

    * Small increases in drag counts at high speeds is a BIG deal. Anybody who ever drives a car at drag limited speeds knows that, don’t even need to go to fighter plane speeds.

    * The F22 is a more unstable aircraft than the Su27. Logically, what limits the ability to fly something more unstable is ultimately limited to the update rates of the flight computer. We all know where that’s going.

    All the above IS aerodynamics. Just because someboy souped up their Pintos and drive at 150mph on the freeway doesn’t make it a sports car when a Ferrari is idling by at 60mph.

    – What do you mean by curved? Changing aerofoil sections or changing camberlines or changing aerofoil section stacking line? :confused:

    – While the F-22 nacelle forebody will not induce the undesirable downwash on the main wing that a canard would, undoubedly it will provide less control authority.

    – No comment (Dunno anything about it)

    – I believe the MiG 1.42/1.44 used a similar autonomous system, although did that aircraft have TVC?

    – Uhhh, aeroelasticity has nothing to do with TVC [it might possibly move the aero centre of a lifting fuselage back, but that would be beneficial], I think you just mean general loadings through the airframe. Also, the reason TVC allows greater supersonic manouverability is that it can be used to retrim for the move in aero centre from subsonic to supersonic flight. That means the elevators remain in their neutral position with full range up or down – giving improved manouverability. The actuator strength is not an issue.

    – Yeap, its proportional to the wing setting angle*V^2, not just V^2 as in subsonics.

    – Dunno what the static margin for either is so cannot comment.

    in reply to: Raptor vs S-300/S-400 SAM #2555776
    kilcoo316
    Participant

    I agree about that. But there is a small important detail left. Depending on speed alone such an aircraft will change its position up to 30 km in just one minute and avoid known threat areas. As I noted several times before, it is one thing to find out that something is coming, but it is much more demanding to find a usefull guideance solution for your SAM. You can not hope that EW-suit of such stealth aircraft will not work, when it shows-up through faulty mission-planning over your SAM-site at all.

    Good point, but what is the rocket range of most modern SAM systems, are we not talking a couple of hundred km?

    Grabbed from another forum:

    S-400: Mach 6.2, range believed to be at least 200 miles
    PAC-2: Mach 5+, range approx 90 miles
    USN SM-3: Mach 8+, range approx 160 nautical miles

    The SA missile range/speed itself is not a problem in my opinion, its tying it all into a coherent location of the target. Perhaps that is what you mean – processing the information quick enough for it to be useful.

    in reply to: Feasability of a mothership #2555962
    kilcoo316
    Participant

    DEW is directed energy weapon

    DOC is direct operating cost [basically the overall cost of an aircraft from purchase to dismantling]

    in reply to: Feasability of a mothership #2555968
    kilcoo316
    Participant

    Oh, and OT, its been estimated that using hydrogen instead of avgas would increase DOC of commercial air by only 25%.

    I was well astounded when I read that, I was fearing a several hundred percent rise in costs.

    in reply to: Feasability of a mothership #2555972
    kilcoo316
    Participant

    Anyway as far as mothership is concerned , the ABL is sort of like a nothership releasing a ton of Lasers to take down missiles , with time they should be able to make a mother ship of DEW’s now that would be something 😉 And then we’ll make way for will smith to come and save the earth while bill gates gives the mothership a cold:)

    Why??

    Will the mothership be using Windows in its computers? :diablo:

    A virus made by microsoft would probably work better than any Norton or McAfee product to be honest 😀 😀

    Onto the thread in general. It should be possible, however, I don’t see the benefit it would bring (apart from maybe ultra quick deployment). But transporting several DEW equipped UCAVs in a C-17 or similar to an airbase would be almost as quick, and definitely a more secure base of operations than a slow target in the sky.

    in reply to: Russia Cuts Back on Fifth Generation #2555983
    kilcoo316
    Participant

    If I was the Russians I’d cancel the whole PAK-FA thing.

    Then I’d go make a 6th generation fighter. A stealthy UCAV with DEWs. What is the point of trying to match the US when you should go one step ahead?

Viewing 15 posts - 481 through 495 (of 721 total)