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Schorsch

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  • in reply to: Japan to consider F/A-22 to replace its F-4s #2504509
    Schorsch
    Participant

    With all do resepect the Typhoon does not offer the level of Air Superiority needed vs advance Russian Types like the Flanker. Really, this is just politics……….Japan is just trying to pressure the US into selling the F-22. Which, is very likely in my opinion.:D

    The stealth features incorporated on the F-22 are to operate in a denied airspace. Not really a feature the Japanese need.

    in reply to: Swing-wing extinction? #2504513
    Schorsch
    Participant

    Do you think there will ever be another new manned swing-wing/variable geometry (VG) combat aircraft?

    No, swing wings are an interim technology and were favored by contradicting requirements. They cause high structural weight, impose limitations in lifetime and limit maneuverability. The main advantages can be achieved easier with other solutions.

    VG is a very good solution when you want to combine large payload, short take off, low landing speed, and high speed capabilities.

    I have problems to see any swing-wings which excel in the points you mentioned. Better say: swing wings are useful to combine the performance of a supersonic jet with acceptable/good field performance.

    VG is best for a wide range of operating conditions – low speed landing/take-off and higher dash speeds.

    The old story. True is that conventional wings will give equivalent cruise speeds in the tactically useful range with minimal fuel penalty. More important for long range dash is the engine and inlet system. Turbofan engines are generally second class choice for that, but offer best compromise.

    All aircraft that earned a swing wing did it because of field performance requirements. The better engine technology more or less cancelled the take-off problem, while landing remains a challenge.
    I guess toughest field performance requirements were imposed on the Tornado, which also excels in being the most specialised airframe. Who ever saw a Tornado wing with all surfaces extended (slats, flaps, spoilers) will see how sophisticated the wings are.

    My favorite swing wing is by the way the MiG-23.

    in reply to: Armed Russian Flights off of Norge #2504776
    Schorsch
    Participant

    It is a very interesting example and proves wrong those people who conclude “small aircraft = small range”. From Bodo to the cap should be ~600km direct course.
    I think the Gripen N could be a very good aircraft, basically tailormade for an air force like that of Norway with different operational aspects as those of Germany or the USA (smaller units, harsher environment). The Eurofighter would also be a useful aircraft.

    in reply to: A350/787 Question #584926
    Schorsch
    Participant

    Just wondering what aircraft Airbus and Boeing designed their A350/787 to replace? My understanding of it at the moment is this:

    Boeing 787-3 = Boeing 757/Boeing 767-200ER
    Boeing 787-8 = Boeing 767-300ER/Airbus A330
    Boeing 787-9 = Boeing 767-400ER
    Boeing 787-10 = Boeing 777-200ER/Airbus A340-300

    Airbus A350-700 = Boeing 767-200ER
    Airbus A350-800 = Boeing 767-300ER/Airbus A330
    Airbus A350-900 = Boeing 777-200ER/Airbus A340-300
    Airbus A350-900R = Boeing 777-200LR/Airbus A340-500
    Airbus A350-1000 = Boeing 777-300ER/Airbus A340-600

    Also, will the A350 design be refined anymore? I know they’ve just confirmed a composite fuselage, A380 nose, and reduced thrust, but none of those has a great impact on appearance, will those ugly wingtips be improved at all? Also, will the ‘XWB’ bit be dropped from the names?

    I think that is a valid list.
    The A350 is still some time before design freeze. By now the data for payload and range, as well as overall performance and dimensions can be considered confirmed. When it comes to materials, I think detailed decisions will come the next year or so. Airbus does not need to outlay exactly what they do from composite and what not. I actually think they will wait at least until the B787 is certified.

    The A350 pleases airlines that never operated something like a B767, for example Lufthansa. Problem for Airbus is that the small family members (traditionally the less efficient) have to compete against the traditionally more efficient stretched versions of the B787. There is no A350-700. The A350-900 will be the basic version and the A350-800 its shrink.

    in reply to: Armed Russian Flights off of Norge #2504857
    Schorsch
    Participant

    I imagine that these intercepts were undertaken by F-16s from Bodø

    Quite a distance. Do Norwegian F-16 operate from Andoya or Harstad/Narvik Evenes?

    in reply to: Armed Russian Flights off of Norge #2504867
    Schorsch
    Participant

    Does someone know from which base the Norwegians normally operate?
    Will the surge in intercepts in any way influence the Norwegian fighter procurement decision?

    in reply to: Ever seen a DC9 reverse out of a gate using reverse thrust #585089
    Schorsch
    Participant

    I thought this was bad for the engines. I thought the reversers should be closed at about 40 knots forward speed. I thought it could cause flameouts or and overheating.

    Possibly your concerns are more related to high bypass under-wing engines with “cold” thrust reversers, which make ~100% of all current Airbus and Boeing aircraft. The DC-9 significantly differs from an average B737 in:
    – having relatively high,
    – empanage mounted,
    – low bypass engines with
    – full thrust reverse (not just cold airflow)

    in reply to: FCS question #2504869
    Schorsch
    Participant

    The crowd-pleasing aerobatics the Russian Flankers and Fulcrums put on feature segments of uncontrolled flight. Was it necessary to modify or override the FCS to allow the jets to gyrate and flip so dramatically?

    My info is yes. Anyways, these are maneuvers well trained and flown by test pilots under favorable conditions, like most airshow maneuvers in the world. On all aircraft since the early 60ies stick-shakers are common that tell the pilot when maximum lift is reached. Normally heavy buffeting would tell anyways.

    Since its the FCS computer accepts input from the pilot and is actually flying the plane, what role does the pilot actually perform in recovering from episodes of uncontrolled flight? Can he just release the controls and trust the FCS to recover the aircraft automatically? Let’s assume we’re talking about the latest jets like a Typhoon or Raptor.

    For first generation fly-by-wire aircraft like the F-16 it was still possible to depart from controlled flight, though it wasn’t easy. On a type like the Eurofighter the controls can be called second generation, the aircraft is in the hands of the automatic control all the time. A departure is under normal conditions not thinkable, if departure appears, I guess the vertical exit is best option for the pilot.

    in reply to: Iranian F-14's and Soviets #2504890
    Schorsch
    Participant

    Most of the older Soviet aircraft may indeed have the “airframe lifetimes” comparable to F-4s or F-15s, but it never seems to happen though, does it?
    For example, some RAF Jaguars have retired with up to 6000 hours on the airframe – I’d love to see a Su-17 or MiG-23/27 with that sort of milage…:rolleyes:

    Underlying reason is mainly the different economic system, I guess. The lifetime heavily depends on load assumptions, and when pilots pull the stick too often too much aft the lifetime drops, happened on the F-16.
    For Soviet systems it is also relevant that overall flight hours were relatively low. And when lifetime limit approached a new type was on the gates. But as bottom line: lifetime is a delicate issue and nowadays I am more careful with claims concerning that, I was less careful before.

    in reply to: Iranian F-14's and Soviets #2504894
    Schorsch
    Participant

    if the F-14s can still be re-engined, that would imply that there is still substantial life left in the airframes..sparsely used or is it that the F-14, like the F-15 had the tremendously long Total airframe fatigue life? the F-15 can fly for upto 15,000 hrs, which is almost twice that of a Mirage-2000, which is twice that of the basic Fulcrum, which is almost twice a basic MiG-21..sometimes that would appear to even out the high initial cost..

    Which is twice … no four … no eight times as much as the squareroute of the average lifetime of a Me-262. So what?
    “Lifetime” of a MiG-29 or MiG-21 can be extended if maintained like an average F-15. The very short lifetime of Russian designs is not necessarily a design flaw but more a garantueed service goal. The expert asks which parts are lifetime limited and what were the assumptions for that. For an F-14 that is easy: the swing wing.

    in reply to: Iranian F-14's and Soviets #2504924
    Schorsch
    Participant

    Of course it’s a cover up !
    They built new ones. The jigs are still intact, they just have been moved to that secret facility.
    And Tomcats are still flying off the USS America, too.

    Ok, I’ll get my coat … 😀

    The F-22 is actually a fixed-wing derivative of the F-14E Total Tomcat, which is totally unknown to the public.

    in reply to: Serial Production of Tu-160 Bombers? #2504945
    Schorsch
    Participant

    I’d finally add that to me the Tu 160 (or even some derivate of the B1A?) would be even more suited than the B1B to the low intensity CAS mission, thanks to its speed allowing for pretty much the same reaction times than a fighter/bomber. After all those CAS plane don’t need to do much low alt flying except for the show of force missions.

    You use the tools you have at hand. In case of Russia, these were financed long ago and the bill is basically paid. But I have the opinion that tactical aircraft can do the mission with better effectivity per spent money. Giving the problems the Russian AF still has from its long underfinancing other areas may be more be more in need of money. First objective should be to bring the high number of tactical aircraft to a state-of-the-art level.

    in reply to: Serial Production of Tu-160 Bombers? #2504952
    Schorsch
    Participant

    Just how many TU-160 s are currently in service?
    Be lucky
    David

    Wasn’t that 14 or so?
    Generally not enough to have an effective force. Re-starting production may be a mean to bring that up to a useful number to at least 20 to 30. The additional question is if these aircraft are all the same standard. Some are surely rebuilt prototype/test aircraft.
    Still, the Tu-160 don’t get better. The chance of penetrating a heavily defended airspace is limited, at least the risk is large. Like the B-1 it is a design of the 1970s. Future investments seem doubtful, other weapons systems may prove to have a higher capability/cost ratio.

    in reply to: 787 service entry – six months delay #585477
    Schorsch
    Participant

    Boeing were practically late on everything , they cought up on a lot of things (some of which i cannot disclose) over the last 24 months , some things were much serious then what issues plague the program now .

    Normal for pretty much every program I guess. Problems were similar for the B747 I guess. And I think Airbus or MDD have not had less issues.

    in reply to: 787 service entry – six months delay #585478
    Schorsch
    Participant

    A FCS isn’t really rocket science, its not as if they changed the number of control surfaces or anything. :confused:

    Even re-sizing the surfaces only really results in gain changes through the different loops, they aren’t fundamental re-codes, more re-tunes.

    I dispute that, at least I want to put that in perspective. Designing flight control laws for a civil airliner is surely not comparable to making such for a fighter aircraft. After all, a civil airliner is restricted to much smaller flight envelope in terms of CG, speed (Mach and IAS), altitude, external stores, angle of attack and sideslip angle.
    BUT the flight control laws have a huge impact on design loads. Little changes in flight control laws may result in 5% more load on the wing. May sound little, but with structure designed to be optimised, it means a lot. Add to that the tendancy of rising OEW (~2-3 tons for the B787 since 2004), you have serious issues at hand.
    Optimisation takes lots of time, it is basically a trade between handling qualities and loads. Boeing has a different approach than Airbus here, and has less experience in control design for civil aircraft (Airbus started 10 years earlier). The whole issue can take time, needs lots of loops and is safety critical. Airbus learned its lessons in the early 90s, and I guess it wasn’t a matter of month.
    Still I don’t understand why Boeing subcontracts this issue to an outside company. This means another interface. Takes time, reduces flexibility.

    EDIT: And do not forget the issues that come with flexibility of the airframe, different than on the previous programs. Airbus will have pain with that, too.

Viewing 15 posts - 2,101 through 2,115 (of 3,480 total)