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  • in reply to: The mighty R-35. Best Turbojet? #2597156
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    I feared it before, you claim …. again!
    Turbine inlet temperature: 1,210 °F (655 °C) for J-79
    +15°C s.l.
    -56°C 40.000 feet
    In the inlet the airspeed is subsonic.

    Sens, the F-4J flying at 40.000 ft at 2,2 Mach has Compressor inlet Temperature limit for J-79 engine, 127 degrees C.

    Every jet engine has its own CIT limit. It depends of engine internal components shapes and materials.

    On the other hand, the R-35 engine of MiG-23 is able to support the aircraft to its airframe limit of 2,35 Mach.

    in reply to: The mighty R-35. Best Turbojet? #2597726
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    Please stop to post such technical nonsense!
    When an engine is allowed for 800 kts IAS at sea level f.e. it is the same TAS there too.
    Go up to 40000 feet for example and see what happens!. When the max allowed is still 800 kts IAS the related TAS is now ?!

    It does not go that way.
    At sea level, the jet engine is limited by dynamic pressure, say 800 KT, but at 40.000 ft it is limited by Compressor Inlet Temperature. For example, the J-79 of F-4J is limited to 127 degrees C, and is not allowed to go faster.

    So, what is allowed at sea level is not allowed at higher altitudes.

    in reply to: The mighty R-35. Best Turbojet? #2597729
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    The YF119 was more like 31,000lbs. Go check the sources of the day. As for drag it’s FAR more complex than “ooh the span has a few degrees less sweep therefore it MUST have WAY more drag”. If you increase drag slightly in one area but reduce it in many others and increase power then what do you think will happen?

    There are aerodynamic equations which show how drag of each component effects total drag.
    Unfortunatelly, the wing sweep and span have the greatest influence.
    The wing thickness ratio above 5% has a great influence, too.

    in reply to: The mighty R-35. Best Turbojet? #2597742
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    “Engine Overview
    Utilizing the same core design as the F101, the F110 engine was created by adding different fan and afterburner packages to tailor engine performance to the desired aircraft application.”

    http://www.geae.com/engines/military/f110/index.html

    Sounds like you need to jettison that “Aviation Fact File” source as your other quotes of it have been equally questionable.

    The point is that the core is the same, only one fan stage was added.

    These are basically the same engine, built for bombers.

    in reply to: The mighty R-35. Best Turbojet? #2597985
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    ROTFLMAO!!!!!! That’s one of your better ones (though with so many to choose from it’s hard to decide). Please explain to us why an F-22 needs 70,000lbs of thrust to go Mach 1.7 when a Foxhound, Eagle, Foxbat, B-58 Hustler, Tomcat, Vigilante and Avro Arrow could ALL do over Mach 2 with far less than that.

    Sferrin, there is no such thing as universal jet engine.
    That is, the jet engine which is equaly good for all speeds.

    Firstly, all above mentioned airplanes achieve 2 Mach with A/B, which means with higher exhaust gas velocity than possible with dry power.

    Second, their aerodynamics is optimised for 2 Mach. Look at fuselage finenes ratio of Hustler and F-22 !!!

    Third, The F-119 engine has too high compressor static pressure ratio, which means that even with A/B it is not capable of speed over 2 Mach.
    No way.

    Also, do you know that if two engines have the same thrust, say 35.000 lb, but one with A/B and another without, the one with A/B will have much higher thrust at supersonic speeds.

    That is because A/B inherently gives higher EGV than possible with Military power.

    in reply to: The mighty R-35. Best Turbojet? #2598001
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    It wasn’t cancelled for technical reasons, McNamara refused to release the funding that Congress had authorized for production. As for the relatively short ranges the weapon system was tested at, that was because the missile was fired at a target all of seven times from a YF-12A. Most weapon system programs undergo a lot more testing than a mere seven launches. They just never got that far thanks to the lack of money.

    Look at this:
    “Lockheed Blackbirds”-Thornborough, Davies:

    -“Because of its demanding and time consuming maintenance, it is tempting to become sceptical at the thought of F-12B interceptors managing to rise to every incrusion by Bear or Backfire.”- page 82

    in reply to: The mighty R-35. Best Turbojet? #2598005
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    Which part of F-14A don’t you understand? Or have you already forgotten the fact that the TF-30 has better performance at high speed?

    What do you mean ? How the TF-30 can have better performance than F-110 at high speed?
    Account of what ?
    The TF-30 is actually the first ever TF with afterburner, with all the vices which can be named.
    -It is super sensitive to high airflow compressor pressures at high speeds, which often caused compressor stalls around 2 Mach.
    -Its high by-pass ratio prevent good performance at high speeds, because of relatively slow exhaust gas velocity, etc,etc.

    Sorry, but these are facts which every Tomcat pilot knows.

    It was simply a bad engine.

    in reply to: The mighty R-35. Best Turbojet? #2556837
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    And I’m sure you’re going to share those calculations, right? Or are they locked up somewhere with the evidence of radome melting on the YF-12A?

    These calculations are understandable only for those who are familiar with Flight Mechanics and Aerodynamic theory.
    As for radome melting in YF-12, do not doubt it at all. And not only that. Its radar could not endure such temperatures much long. Simply, it did not work well at such temperatures. Look at missile ranges achieved with AIM-47 in tests. Only a fraction of their potential.
    That was only one of many technical reasons why it has been cancelled.

    in reply to: The mighty R-35. Best Turbojet? #2556838
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    Compare that with 2,35 Mach speed of R-35 powered MiG-23ML, with 2 large R-23 underwing missiles, and you will get the picture of TJ and higher by-pass TF.

    The Mig is 0,5 Mach faster , with much draggier warload.

    The same applies to climb and acceleration.

    in reply to: The mighty R-35. Best Turbojet? #2556839
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    And that’s also with a much more draggy twin-pod system mounted under the nose.

    That drag is insignifficantly higher, but note that it has much, much more powerful engines than F-14A.

    And you conveniently ignored the part where it says that if the aircraft is clean or carrying 2 AIM-9s it can hit Mach 2.0 at 40,000 feet and higher.

    Of course not, but you must understand that the max speed has to be attainable in much more range of altitudes, than in one point in Height-Speed diagram.

    The F-14D can attain 2 Mach clean , but that is practically useless because it can be achieved in very narrow height range.

    Pilot reports, in Aviation Week, say that service F-14D can attain 1,88 Mach clean.

    in reply to: The mighty R-35. Best Turbojet? #2556842
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    “Today I flew the Raptor at speeds exceeding (Mach 1.7) without afterburners,” General Jumper said. “To be able to go that fast without afterburners means that nobody can get you in their sights or get a lock-on. The aircraft’s impressive stealth capability, combined with its super cruise (capability), will give any adversary a very hard time.”

    “The F-22 is fast, I mean it’s really fast. The top speed is classified but it’ll do 1600 mph.” Paul Metz, F-22A Chief Test Pilot

    Two slightly more authoritative sources than your web pages.

    These are typical propaganda statements of military officer and company official, without any foundation in Flight Mechanics.

    Sferrin, are you aware that for 1,7 Mach without afterburner, its engines should have about 35.000 lb thrust each, in dry power.!!!

    in reply to: The mighty R-35. Best Turbojet? #2556848
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    Maybe you could explain how an F-4 (an aluminum airplane) set the world speed record at Mach 2.62 then?

    The record was not 2,62 Mach but 2,43 Mach (2585 km/h).

    And I realy doubt that it is used again.

    The limit for service AL plated aircraft is 2,35 Mach.

    Both the F-14A and F-111 can easily exceed Mach 2 in level flight. You can babel on all you like that doesn’t change the facts. And the F-111F is good for Mach 2.5.[/QUOTE]
    Sferrin, you do not want to see reality.
    The manual of F-14D, with much more powerful F-110 engines, says:

    -1,85 Mach with 4 Sparrows.
    -1,75 Mach with 4 Phoenixes.

    And that with variable intakes.

    Regarding F-111F, nobody ever has pushed it to that speed in service. In test may be.

    in reply to: The mighty R-35. Best Turbojet? #2556856
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    Above Mach 1.4 can mean anything from Mach 1.41 to Mach 37.

    Above 1,4 Mach means anything between 1,41 and 1,49 Mach.

    Otherwise, it would state ” above 1,5 Mach”.

    Aerodynamic equations show that service F-22A has about 1,45 Mach speed without A/B.

    in reply to: The mighty R-35. Best Turbojet? #2558431
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    By-pass of F-14A:

    -“The TF-30 P-412 has 0,9 by-pass ratio”

    Aviation Fact File: F-14, page 31

    Aviation Fact File: B-1B, page 39

    in reply to: The mighty R-35. Best Turbojet? #2558435
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    The F-22A speed:

    http://www.F-22raptor.com

    The Max A/B speed is 1,8 Mach, and max dry speed is 1,5 Mach.

    http://www.globalsecurity.org (F-22/engines):

    “the max speed is above 1,4 Mach without A/B”.

Viewing 15 posts - 241 through 255 (of 644 total)