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  • Peter Kesternich
    replied
    Originally posted by 3WE View Post
    but hey Peter I know what you are saying, and I think you'd agree on me calling a 757 an "effecieincy" machine- even though a glider might beat the heck out of it on "miles per gallon of jet fuel".
    no hard feelings... Just to make things crystal clear again: The whole thread started with a discussion of a takeoff experience in a 757. What I was talking about was 'speed' as pertaining to the time an aircraft needs to get you off the ground, i.e. acceleration and takeoff performance. That's where you get to really "feel" the speed and power of an aircraft. Once you are up at cruising altitude speed is only relevant as it relates to the time you need to reach your destination. You do not "feel" it - and definitely you do not "feel" the difference between an aircraft cruising at M.74 like a DC-9 and at M.86 like a 747-400.

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  • 3WE
    replied
    Originally posted by SYDCBRWOD View Post
    Go show me where Peter was comparing cruising speeds.
    Right here where he said:

    Originally posted by Peter
    The only area where 707s, MD-80s, and 747s could blow the doors off a 757 is noise produced during takeoff run
    in contradiction to my post which said:

    Originally posted by Me
    Rocket? I was thinking slow
    Anyway- I think Peter and I understand each other. I made some exagerated comments (to try and make a point)- and he took issue with them. And he even said some strange things to make his point (speed doesn't figure in his definition fast). I'll give him a little grief over that- but hey Peter I know what you are saying, and I think you'd agree on me calling a 757 an "effecieincy" machine- even though a glider might beat the heck out of it on "miles per gallon of jet fuel".

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  • 3WE
    replied
    Originally posted by Peter Kesternich View Post
    Thanks for distorting my quote, 3WE... One could almost come to believe that you were a politician
    No distortion. Your sentence and my paraphrase (highlighting trivial things like the subject and verb) indicate the same thing: You have an awfully strange defintion of fast.

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  • Peter Kesternich
    replied
    Originally posted by Peter Kesternich View Post
    (...) Cruise speeds don't figure into my definition of a fast aircraft (...) when I talk about a fast or sporty aircraft, cruise speed doesn't figure into my considerations. (...)
    Originally posted by 3WE View Post
    Well, I take issue with your statment that "speed doesn't figure in the definition of fast"
    Thanks for distorting my quote, 3WE... One could almost come to believe that you were a politician

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  • SYDCBRWOD
    replied
    Originally posted by 3WE View Post
    Go reread everything...you have selective "hearing".
    Go show me where Peter was comparing cruising speeds.

    My hearing's fine, thanks for your concern.

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  • 3WE
    replied
    Originally posted by Gabriel View Post
    Maybe it's because the 757 typically doesn't take off as close as MTOW as other planes do?

    I flew a 757 once, from Buenos Aires to Princess Juliana non-stop. It was 100% full of passengers in one class (the most cramped coach I've ever seen). It was a charter flight (operated by LAPA) with everybody on-board having bought an at-least-one-week vacation package, so everybody had some heavy suitcases.

    I don't remember being surprised by any out-of-the-ordinary performance.

    Take-off acceleration and climb performance (specially at low speed / low altitude) is a matter of mainly thrust-to-weight ratio.

    On the other hand, one of the most stringent limitations for the engine size (rated thrust) on the low side is the one-engine-inop take-off and initial climb performances at MTOW, which again are a matter of thrust-to-weight (except thrust with only one engine).

    That's why twins at MTOW tend to have a more-or-less similar acceleration and climb performance, and it's better that those in a four-engines plane (which would still have 75% of the installed thrust available after one engine quits)
    I've flown on a lot of full 757's but I'm thinking that the fuel load was probably on the light side (2-4 hour flights). Frankly, I've never felt that accelation was that impressive.....other than it keeps accelerting.

    What does get me is how high the nose attitude feels...on ALL airliners.

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  • Gabriel
    replied
    Originally posted by Peter Kesternich View Post
    Going back to the original scenario of takeoff, I definitely stick to my statement that not many passenger aircraft at normal weights give you a kick like the 757.
    Maybe it's because the 757 typically doesn't take off as close to MTOW as other planes do?

    I flew a 757 once, from Buenos Aires to Princess Juliana non-stop. It was 100% full of passengers in one class (the most cramped coach I've ever seen). It was a charter flight (operated by LAPA) with everybody on-board having bought an at-least-one-week vacation package, so everybody had some heavy suitcases.

    I don't remember being surprised by any out-of-the-ordinary performance.

    Take-off acceleration and climb performance (specially at low speed / low altitude) is a matter of mainly thrust-to-weight ratio.

    On the other hand, one of the most stringent limitations for the engine size (rated thrust) on the low side is the one-engine-inop take-off and initial climb performances at MTOW, which again are a matter of thrust-to-weight (except thrust with only one engine).

    That's why twins at MTOW tend to have a more-or-less similar acceleration and climb performance, and it's better that those in a four-engines plane (which would still have 75% of the installed thrust available after one engine quits)

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  • 3WE
    replied
    Originally posted by Peter Kesternich View Post
    SYDCBRWOD is right. I was talking about acceleration and climb - since the whole thread started with the description of a takeoff experience in a 757.
    Cruise speeds don't figure into my definition of a fast aircraft - especially since selecting cruise speeds depends on - like 3WE said - how fast you want to fly (and how economical you want to do this). Concerning cruise speeds the 757 is in the middle of the spectrum, doing around M.78-M.80 at altitude. I have no idea, where a.net got their figures, but these are probably the max cruise speeds. DC-9s at Delta/Northwest for example regularly cruise at M.74-M.76 and that's quite a bit slower than the 757. The important thing to note is that aircraft almost never cruise as fast as they can, so when I talk about a fast or sporty aircraft, cruise speed doesn't figure into my considerations.
    Going back to the original scenario of takeoff, I definitely stick to my statement that not many passenger aircraft at normal weights give you a kick like the 757.
    Well, I take issue with your statment that "speed doesn't figure in the definition of fast" , but aside from that would not argue. Thanks for the discussion.

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  • Peter Kesternich
    replied
    SYDCBRWOD is right. I was talking about acceleration and climb - since the whole thread started with the description of a takeoff experience in a 757.
    Cruise speeds don't figure into my definition of a fast aircraft - especially since selecting cruise speeds depends on - like 3WE said - how fast you want to fly (and how economical you want to do this). Concerning cruise speeds the 757 is in the middle of the spectrum, doing around M.78-M.80 at altitude. I have no idea, where a.net got their figures, but these are probably the max cruise speeds. DC-9s at Delta/Northwest for example regularly cruise at M.74-M.76 and that's quite a bit slower than the 757. The important thing to note is that aircraft almost never cruise as fast as they can, so when I talk about a fast or sporty aircraft, cruise speed doesn't figure into my considerations.
    Going back to the original scenario of takeoff, I definitely stick to my statement that not many passenger aircraft at normal weights give you a kick like the 757.

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  • 3WE
    replied
    Originally posted by SYDCBRWOD View Post
    He didn't claim it was one of the faster airliners. He claimed it could be called sporty (compared to other airliners presumably).

    That could and probably does mean he considered it to be fast accellerating and climbing...

    Over to you Peter...
    Go reread everything...you have selective "hearing".

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  • SYDCBRWOD
    replied
    Originally posted by 3WE View Post
    Ok Peter- I challenge you to a little debate/dissect.


    So- anyway- Do you stick to your argument that it's one of the faster airliners? If so- what's your basis, data or explanation?
    He didn't claim it was one of the faster airliners. He claimed it could be called sporty (compared to other airliners presumably).

    That could and probably does mean he considered it to be fast accellerating and climbing...

    Over to you Peter...

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  • 3WE
    replied
    Ok Peter- I challenge you to a little debate/dissect.

    I went to airliners.net and found these figures (I did round a couple by a couple of kts). This was "crusie speed" and of course the true cruse speed depends on a lot of factors including how fast you want to fly.

    757-200 : 460 kt
    707: 480 kt
    747: 490 kt
    MD80: 440 kt
    DC-8 60/70 480 kt
    L-1011: 460 kt
    DC-9 30 : 480 kts

    So, yep- I was cleary wrong on the MD-80.

    Still, it looks to me like the 757 on the slower end of the spectrum.

    Ok- you said "power".....I would not argue that. As I said in my post it seems to march very effortlessly up to FL410.

    However it does have nice, big, not-so-swept wings to generate more lift at slower speeds......

    There's a rule of thumb though- power gives you a lot more climb rate than it does speed.

    Now for the word mincing.....I'll confess I used some overly strong words and was being a bit sarcastic....but I think I might be safe calling it an "effeciency machine". BUT, I don't think it can be called a rocket ship either if you want to be technical.

    So- anyway- Do you stick to your argument that it's one of the faster airliners? If so- what's your basis, data or explanation?

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  • Peter Kesternich
    replied
    Originally posted by 3WE View Post
    Rocket? I was thinking slow, cumbersome, glider-like efficiency-machine with a big wing (...)
    707's, MD-80s, 747s will blow the doors off a 757 (to some extent) Those are more deserving of the term "rocket"
    Hmmmmmmm - think again. The 757 is one of the best-powered commercial airliners ever built and if there is any aircraft since the DC-9-10/-20 that deserved the nickname "sport" then it's the 757. The only area where 707s, MD-80s, and 747s could blow the doors off a 757 is noise produced during takeoff run

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  • 3WE
    replied
    Originally posted by mzk49o1 View Post
    That may be because the 757 is something of a rocket.
    Rocket?

    I was thinking slow, cumbersome, glider-like efficiency-machine with a big wing that gets you off with gentle acceleration and with every seat full, will march right to FL410 without hesitation nor stalling on arrival (as empty CRJ's sometimes do)

    707's, MD-80s, 747s will blow the doors off a 757 (to some extent) Those are more deserving of the term "rocket"

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  • dkmax
    replied
    Thank you for your replies guys.

    I must have done 50 or so flights since, without anything like a similar recurrence, so I thought I'd 'consult the oracle' just to clear my mind

    I mean a wild ride take off & landing in the same flight got me thinking, particularly as the guy who mentioned the 'practice/suspected' gear failure was an A300 Freight Pilot :-o

    Also, having read the book (Flying The Big Jets), it just seemed like there were so many pre flight calculations & procedures to be completed - distances, velocities, take off weight, obtaining clearance (airport was very busy) that merging with the runway from a slip road with 1/4 of the runway gone negated all of this. Though I guess you could easily calculate the required speed when joining the runway to achieve the same V1 result. It certainly felt like we were well above 40knots even before merging with the runway.

    As for the landing, guess it was just a cross wind - though sure seemed strange, continuing on right main gear for so long before finally using both, reverse thrust & braking.

    Seems like almost everybody has a dodgy flight story, that's mine put to bed!

    Thanks all

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