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Guest bgahan

757 Way Too Fast

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HI Everyone,I know it has been said here before, but this plane does seem to have way too much power. I know the real life 757 likes to fly as said here before but this is a bit much.For starters I blow right through V2+15 in no time. In fact, I'm just off the ground (like seconds) and I'm already passed my first flap retraction schedule. Here was my latest flight data:OEW = 136,940Pax/Cargo = 31,460PZFW = 168,440Fuel = 20,000GW = 188,437CG = 22%Trim = 7.00%Route, KPHX BXK2 PKE J4 TNP SEAVU1 KLAX (58 minutes)I look at my AWA speed reference book and it shows the followingV1 = 137VR = 137V2 = 144V2+15 = 159I took off from 7L in Phoenix. By the time I made the inital turn (at 4DME PXR) to head toward the first BXK fix, I was already climbing through 18,000. So this plane climbs to 18,000 in 4-8 NM? My scheduled altitude was 30,000. I made 30,000 feet in 9 minutes. I did use a de-rate of 1.71 EPR after climbing through 1,000 AGL. I have flown on many 757's just like most of us, and I can tell you that there is no way, that in real life a 757 can climb to 30,000 in 9 minutes. I know 188K GW is light but that seems a bit ridiculous.Either I am doing something wrong or this is overpowered. Or I am nuts! Any thoughts or suggestions would be appreciated.Thanks,Brian

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Brian,I will resist on calling you nuts unless you insist :)Not being typed on the 757 I defer to those who are and who gave this plane a serious run for its money. Aside from the power required to get the plane off the blocks, the heneral concensus was that it performed pretty close to the money. That said, Rob Young the dynamics guru called me last night with a couple of minor tweaks based on additional feedback, so whilst we do listen, I'm sorry to say that in regards to climb, we have to take the word of those suitably typed and flying the real thing on a daily basis.

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Hi Norman,Thanks for the reply. I trust that you guys did your due dilegence. I can't believe though that the 757 can climb to 30,000 in 9 minutes. So I guess I am nuts. I will say though, that I am not sure whether I used the correct de-rate, b/c I don't have charts for that. However, I am concerned that I'm blowing through V2+15 and first flap retraction within seconds of being off the ground. Otherwise I would not care. Is this happening to you as well?Brian

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>Is this happening to you as well?Its the one plane that keeps me out of my Airbus. I tend to not use TOGA for departures and try to fly the plane manually to 10K hand flying the SID.Yes its tough to keep it V2+15 but not impossible.

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The British Airways Virtual fleet training captain wrote in this forum that real British Airways use TO2 and 60 degrees derate. You did not mention takeoff thrust used, but if you used TO, then no wonder this is what you saw. Secondly, you loaded your aircraft with around 140 passengers, good for a 737-700. 200 passengers with luggage weigh around 50,000 Lb, 250 weigh more. Airlines strive to carry revenue cargo, add another 30,000Lb. I'm not sure that a one hour ride is really that typical of the aircraft, although I have flown 25 minute domestic flights with it. A typical 40,000LB fuel load could be proper for 4 hour flights. Now that your weight approahes the design maximum, V speeds are higher and engines properly derated, try aircraft excess energy (the rate of increase of speed and altitude) again and tell us how it feels, is that still the famous rocket? probably not, especially in Phoenix Sky Harbor's common 40 degree centigrade air temperature, affecting airframe performance and handling, not only thrust.>HI Everyone,>>I know it has been said here before, but this plane does seem>to have way too much power. I know the real life 757 likes to>fly as said here before but this is a bit much.>>For starters I blow right through V2+15 in no time. In fact,>I'm just off the ground (like seconds) and I'm already passed>my first flap retraction schedule. >>Here was my latest flight data:>>OEW = 136,940>Pax/Cargo = 31,460>PZFW = 168,440>Fuel = 20,000>GW = 188,437>CG = 22%>Trim = 7.00%>>Route, KPHX BXK2 PKE J4 TNP SEAVU1 KLAX (58 minutes)>>I look at my AWA speed reference book and it shows the>following>>V1 = 137>VR = 137>V2 = 144>V2+15 = 159>>I took off from 7L in Phoenix. By the time I made the inital>turn (at 4DME PXR) to head toward the first BXK fix, I was>already climbing through 18,000. So this plane climbs to>18,000 in 4-8 NM? My scheduled altitude was 30,000. I made>30,000 feet in 9 minutes. I did use a de-rate of 1.71 EPR>after climbing through 1,000 AGL. >>I have flown on many 757's just like most of us, and I can>tell you that there is no way, that in real life a 757 can>climb to 30,000 in 9 minutes. I know 188K GW is light but>that seems a bit ridiculous.>>Either I am doing something wrong or this is overpowered. Or>I am nuts! Any thoughts or suggestions would be appreciated.>>Thanks,>Brian>>>>

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NormanThat is such a cool video - I've seen it a couple of times. Tried doing it with my 757 - first time I tried at 100ft, a little crash and burn...second time - at 200ft - managed it and a nice powerful climb. Did it in an AA with PW engines...nice and powerful.

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You had a 188,000 GTOW? Man you are flying that thing empty. No wonder why it climbs that quick. And yes, i bet you any money it would climb that quick if you were that light. I was flying with a guy at air canada jazz that used to fly for air transat on the 57 and he said they used to be able to peg that vsi up to 20K feet.Jack

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>I thought I best share a link sent to me by our friends over>at www.flightdecksolutions.com shows just how fast a 757 can>climb :)>>http://media.putfile.com/High-speed-flyby-Holy Smokes thats awesome! I'm a jet mechanic in the US Navy, and routinely get to witness AWESOME jet performance. That is in the realm of "pointy nose" stuff!

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As B757 Engineer...I have to say that this aircraft is really a rocket!I

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Norman,I seen that same RNZAF 757 do the flying display at the Australian International Airshow last year. I was amazed at how the pilots flew that 757. It was just like they were flying a fighter jet. On the take off run they got airborne and then did a 90deg angle of bank and then 757 was probably only 400ft off the rwy. The kept it that low and did a hight speed pass and went almost vertical. I would say at about 70 to 80 deg strait up. at the end of the climb the 757 rolled over to the left and the plane was almost right upside down! I kid you knot. That 757 hit 15,000ft in about 20 seconds! It truly was amazing to watch! It looks like that video showed the same stunt.Pete

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And I must say that to fly in and out of Eagle they need every bit of that "fighter performance" LOL. Fly a runway 25 aprach to KEGE, with a circle to land on RWY 7 -- you'll see what I mean ;-) OH! And the best part -- take off from RWY 25 :-) Fun stuff :-) The 757 is the only airliner of her size even allowed into KEGE (besides military). All others are CRJ sized or smaller.

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I wish I could save that 757 vid!Anyway, my grandfather (ret. nwa captain) flew the 757 and said it was a true rocket. You had to pull throttle way back to stay under 250, and it would be yelling at you to put throttle up.

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Uhm . . . . . excuse me while I go do some of that in the Sim :-)Hee hee

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Yes, I posted that same video on another thread. A lot of people don't realize the climb rates that can be achieved by a lightly loaded airliner.Regards, Carlos

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I can't remember what site I downloaded it from but I have the file. If you can't find it e-mail me at chaconc@bellsouth.net and I will send it to you.Regards, Carlos

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People often mistake pasenger aircraft as numb and dumb because all they witness is the actual flight when they ride in one. They are designed for performance and are no different then any other aircraft. They are all capable of things that will never be realized by pasengers because airlines don't want there pasengers puking everywhere and it is not efficient.

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This is why I posted a question to PSS about getting us information (specifically charts) concerning to what extent we should de-rate takeoff thrust based on load and runway length.That way you dont go in orbit on each departure.Best,Chris

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Let me elaborate on passenger aircraft performance, what kind of performance they have and how they get it. The performance relies on a few key factors: power plant, aerodynamic and structure technologies. Power plant technology defines attainable thrust, fuel consumption, and maintainability. Aerodynamic design defines airflow characteristics, specifically lift to drag ratio, with focus on fast cruise. Structure knowhow determines empty aircraft weight. Aircraft weight appears in the denominator of relevant aerodynamic equations.Aircraft designers on one side, and major carriers on the other, define foreseen market needs, for the various categories of air transport, for example- is there an economically justified need for Sydney to London and similar routes carrying 850 passengers plus 50 tons of freight. Thousands of design iterations are run on supercomputer to forsee what the market would best utilize 30 years on- 5 years for maturing the technology and designing the aircraft and 25 for its lifecycle. Once a design is selected, the engine manufacturers utilize their technology and taylor it to mission design in terms of thrust, diameter and maintainability. The Boeing 747, 767 and 777 drove such new engine designs. Along the lifecycle of an engine, it is uprated and improved based on experience and tweaks, around 20% thrust could be added that way. An aircraft design includes cruise altitude and Mach No., and payload range performance. A transport aircraft cruising above and clear of most other traffic at FL460 (I flew there in a B767-100 over the US), would be able to file shorter routes and get more ATC directs during cruise. Cruise performance, coupled with mission weight and drag define the thrust required. This is how and why your rocket is conceived in general terms. Not for high speed pull-ups at airshows.p.s. Having worked in aircraft design a liftime, I wanted to also say that in earlier days, aircraft design was in the hands not of a few thousand engineers but rather of single aircraft designers, like Howard Hughes. These were geniuses who could beat any supercomputer in the ability to put quickly together a winner. They no longer exist if I am correct, simply an extinguished breed. The last one I spent time with is Harry Hillaker, father of the F-16. >People often mistake pasenger aircraft as numb and dumb>because all they witness is the actual flight when they ride>in one. They are designed for performance and are no different>then any other aircraft. They are all capable of things that>will never be realized by pasengers because airlines don't>want there pasengers puking everywhere and it is not>efficient.

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