Delta Virtual Airlines Water Cooler | Airline Operations |
Fleet 757 overpowered? |
DVA7130
Senior Captain, B727-200
OLP
Joined on March 23 2009
50 State Club
Everett 250 Club
Events Century Club
DVA Five-Year Anniversary
Eight Century Club
Online Eight Century
"Hudson, we have a problem" Tyrone, GA USA
846 legs, 1,482.4 hours
814 legs,
1,429.8 hours online 818 legs,
1,443.2 hours ACARS 178 legs,
322.6 hours event
|
Posted onPost created on
June 15 2011 21:00 ET by Ryan Morse
|
I have a problem with the Fleet 757. At cruise I often will have a GS of 570, with no wind. I have been comparing the CFG's of the fleet 757 and the CS 757 demo. (fleet on left) Does any one see any major differences that could cause this? I do also have problems with N2 being high, but I guess that can be explained by the rated_N2_rpm being much higher.
Thanks
|
DVA9589
First Officer, A320
Joined on March 14 2011
50 State Club
US Coastal Club
Commuter Conquest
Millennium Club
US Mountaineer Club
Globetrotter
DVA Ten-Year Anniversary
Everett 500 Club
Stuart, IA USA
1,464 legs, 2,331.9 hours
45 legs,
90.3 hours online 1,450 legs,
2,311.2 hours ACARS 4 legs,
8.4 hours event
|
Posted onPost created on
June 16 2011 00:19 ET by Randy Donnelly
|
We noticed that also on Vatsim. You blew by us on our way to COS like we were standing still. You sarted way behind us and ended up a 100mi ahead of us. PMDG 737 using ASE weather. It caused a little concern with ATC. Having RW upper level winds makes a huge difference also. Call ya Blubyme The fleet 757 probably has way less parasitic drag programmed in it. engine numbers are similiar.
Randy DonnellyFirst Officer, A320
|
|
DVA7130
Senior Captain, B727-200
OLP
Joined on March 23 2009
50 State Club
Everett 250 Club
Events Century Club
DVA Five-Year Anniversary
Eight Century Club
Online Eight Century
"Hudson, we have a problem" Tyrone, GA USA
846 legs, 1,482.4 hours
814 legs,
1,429.8 hours online 818 legs,
1,443.2 hours ACARS 178 legs,
322.6 hours event
|
Posted onPost created on
June 16 2011 01:02 ET by Ryan Morse
|
Hmm, for the sake of VATSIM controllers. Could anybody please donate me a number with a decimal to live in my parastic_drag_scalar line?
|
DVA1008
Senior Captain, B757-200
Joined on December 14 2002
B757 100 Club
Everett 250 Club
50 State Club
Six Century Club
Online Six Century Club
DVA Fifteen-Year Anniversary
"Fly 'till the map turns blue" Kokomo, IN
633 legs, 1,731.3 hours
613 legs,
1,689.9 hours online 212 legs,
792.3 hours ACARS 35 legs,
77.7 hours event
|
Posted onPost created on
June 16 2011 11:04 ET by Matt Young
|
The parasitic drag isn't what you want to change. Parasitic drag accounts for dirt, dead bugs, and other things that would be parasites to the airframe. You MIGHT want to change induced drag, but I'm not necessarily convinced that's where the problem lies. Without doing some test flights and tuning myself, I'm not going to throw any numbers at you.
Matt YoungSenior Captain, B757-200
|
|
DVA9589
First Officer, A320
Joined on March 14 2011
50 State Club
US Coastal Club
Commuter Conquest
Millennium Club
US Mountaineer Club
Globetrotter
DVA Ten-Year Anniversary
Everett 500 Club
Stuart, IA USA
1,464 legs, 2,331.9 hours
45 legs,
90.3 hours online 1,450 legs,
2,311.2 hours ACARS 4 legs,
8.4 hours event
|
Posted onPost created on
June 16 2011 22:37 ET by Randy Donnelly
|
Ya. Thats what I was thinking. Bugs dont have that much drag. I stand corrected
[flight_tuning]
cruise_lift_scalar =1.000
parasite_drag_scalar =1.000
induced_drag_scalar =1.1
elevator_effectiveness =1.0
aileron_effectiveness =1.0
rudder_effectiveness =1.0
pitch_stability =1.000
roll_stability =1.000
yaw_stability =1.000
elevator_trim_effectiveness =0.800
aileron_trim_effectiveness =1.000
rudder_trim_effectiveness =1.000
Randy DonnellyFirst Officer, A320
|
|
DVA7130
Senior Captain, B727-200
OLP
Joined on March 23 2009
50 State Club
Everett 250 Club
Events Century Club
DVA Five-Year Anniversary
Eight Century Club
Online Eight Century
"Hudson, we have a problem" Tyrone, GA USA
846 legs, 1,482.4 hours
814 legs,
1,429.8 hours online 818 legs,
1,443.2 hours ACARS 178 legs,
322.6 hours event
|
Posted onPost created on
June 16 2011 23:44 ET by Ryan Morse
|
It looks like your Induced drag is lower than the fleet's.
|
DVA1763
Senior Captain, B757-200
Joined on June 29 2004
Everett 250 Club
Online Six Century Club
DVA Ten-Year Anniversary
Seven Century Club
Oklahoma City, OK
723 legs, 2,015.0 hours
645 legs,
1,824.0 hours online 585 legs,
1,608.7 hours ACARS 10 legs,
44.8 hours event 740 legs, 2,044.9 hours total
|
Posted onPost created on
June 17 2011 00:55 ET by Steve Pickle
|
A GS of 570 with ZERO wind seems very believable to me.
Mach .82 is 542 knots, so if you factor in altitude etc., that's about right. You should really consider investing in Active Sky Evolution if you fly online often.
|
DVA2728
Captain, MD-11
E-MAIL
Joined on December 04 2005
Triple Century Club
Online Triple Century Club
DVA Fifteen-Year Anniversary
Tri-Jet Double Centruy CLub
Million Mile Club
"Exceeding the standard." March Air Reserve Base, CA
343 legs, 2,038.9 hours
317 legs,
1,833.0 hours online 292 legs,
1,778.6 hours ACARS 6 legs,
27.9 hours event
|
Posted onPost created on
June 19 2011 19:46 ET by Shane Olguin
|
You know, if you add this to the issue tracker I can have Luke assign it to me and I'll take a look.
|
DVA2728
Captain, MD-11
E-MAIL
Joined on December 04 2005
Triple Century Club
Online Triple Century Club
DVA Fifteen-Year Anniversary
Tri-Jet Double Centruy CLub
Million Mile Club
"Exceeding the standard." March Air Reserve Base, CA
343 legs, 2,038.9 hours
317 legs,
1,833.0 hours online 292 legs,
1,778.6 hours ACARS 6 legs,
27.9 hours event
|
Posted onPost created on
June 20 2011 23:00 ET by Shane Olguin
|
I think I'll just start working on this one and see what I can come up with. Was this in FS9 or FSX?
|
DVA2728
Captain, MD-11
E-MAIL
Joined on December 04 2005
Triple Century Club
Online Triple Century Club
DVA Fifteen-Year Anniversary
Tri-Jet Double Centruy CLub
Million Mile Club
"Exceeding the standard." March Air Reserve Base, CA
343 legs, 2,038.9 hours
317 legs,
1,833.0 hours online 292 legs,
1,778.6 hours ACARS 6 legs,
27.9 hours event
|
Posted onPost created on
June 20 2011 23:15 ET by Shane Olguin
|
Oiiii... well I just looked at everything. This is going to need a complete makeover! It's all over the place. I should be able to help out though as I have some reasonably good data for PW2040s. I work on C-17s at work and they use the military equivelant of that engine so I've got some great data for engine parameters. I'll get to work!
|
DVA7130
Senior Captain, B727-200
OLP
Joined on March 23 2009
50 State Club
Everett 250 Club
Events Century Club
DVA Five-Year Anniversary
Eight Century Club
Online Eight Century
"Hudson, we have a problem" Tyrone, GA USA
846 legs, 1,482.4 hours
814 legs,
1,429.8 hours online 818 legs,
1,443.2 hours ACARS 178 legs,
322.6 hours event
|
Posted onPost created on
June 20 2011 23:58 ET by Ryan Morse
|
Yeah, I always had a funny fealing with it. It is FSX.
|
DVA2728
Captain, MD-11
E-MAIL
Joined on December 04 2005
Triple Century Club
Online Triple Century Club
DVA Fifteen-Year Anniversary
Tri-Jet Double Centruy CLub
Million Mile Club
"Exceeding the standard." March Air Reserve Base, CA
343 legs, 2,038.9 hours
317 legs,
1,833.0 hours online 292 legs,
1,778.6 hours ACARS 6 legs,
27.9 hours event
|
Posted onPost created on
June 21 2011 10:56 ET by Shane Olguin
|
Got it, I'm working on it now.
|
DVA7922
Senior Captain, MD-88
OLP
Joined on November 04 2009
50 State Club
Online Century Club
Triple Century Club
Globetrotter
"Student Pilot: "Um, Your controls."" Dallas, GA USA
384 legs, 1,292.5 hours
128 legs,
221.9 hours online 382 legs,
1,281.7 hours ACARS 18 legs,
40.6 hours event
|
Posted onPost created on
June 21 2011 11:22 ET by Charles Carter
|
Matt Young wrote:
The parasitic drag isn't what you want to change. Parasitic drag accounts for dirt, dead bugs, and other things that would be parasites to the airframe. You MIGHT want to change induced drag, but I'm not necessarily convinced that's where the problem lies. Without doing some test flights and tuning myself, I'm not going to throw any numbers at you.
Parasite Drag includes many things, one of the biggest components of parasite drag is form drag. Form drag is drag from the form of the airframe. Every little (and large) piece of the plane that protrudes into the airflow increases form drag, and therefor parasite drag. You could include bug guts and dirt in that, but the airframe itself is what generates the majority of parasite drag.
Induced Drag is the drag that is generated as a by-product of creating lift because of changing the direction of airflow around the wing.
*None of this necessarily helps with the fleet 757 problem, but should provide a little better understanding of aerodynamics. :-)
Charles CarterSenior Captain, MD-88
|
|
DVA7670
First Officer, B777-200
Joined on August 14 2009
DVA Five-Year Anniversary
"Any landing you can walk away from..." Sharpsburg, GA USA
77 legs, 354.3 hours
75 legs,
349.5 hours ACARS
|
Posted onPost created on
July 17 2011 14:53 ET by Dustin Thames
|
I was having the same issue with the QW757, but discovered that the model was using PW2043's (instead of PW2037) on the 752 model. Not sure if this is happening here, but thought I'd throw it out there.
EDIT: Just took a closer look at the cfg files above. Static thrust for a PW2037 (engine on DAL's 757-200 fleet) is 37530 pounds, so the fleet thrust is a little bit higher than normal. The engine in the CS757 cfg you have above is a PW2040, which is only on DAL's 757-300 fleet, IIRC. I also agree that the N2 value in the fleet 757 is incorrect. The one in the CS cfg is closer to reality.
Dustin ThamesFirst Officer, B777-200
|
|
DVA9589
First Officer, A320
Joined on March 14 2011
50 State Club
US Coastal Club
Commuter Conquest
Millennium Club
US Mountaineer Club
Globetrotter
DVA Ten-Year Anniversary
Everett 500 Club
Stuart, IA USA
1,464 legs, 2,331.9 hours
45 legs,
90.3 hours online 1,450 legs,
2,311.2 hours ACARS 4 legs,
8.4 hours event
|
Posted onPost created on
July 18 2011 19:15 ET by Randy Donnelly
|
Overpowerd. probably not. Too slick, perhaps. Rw aviation engineers would love to have that problem!
Randy DonnellyFirst Officer, A320
|
|