Take-off distance

Hi,

 

Got recently L1011 and DC10, both great to fly with amazing genuine cockpits but noted that L1011 with full throttle can rotate at 125 knots easily (too early) while the DC10 needs to achieve at least 175 knots to be able to rotate (too late). Both aircraft have roughly the same weights in aircraft.cfg. I played with the figures in both cfg files in attempt to increase take-off distance (speed) in L1011 and reduce it in DC10 but to no avail. Any help in what figures to change would be much appreciated.

For info, I am attaching the main portions from both cfg files:

 

L1011

[WEIGHT_AND_BALANCE]

max_gross_weight = 660000 // (pounds)

empty_weight = 281680 // (pounds)

 

reference_datum_position = 0, 0, 0 // (feet) distance from FlightSim Reference position: (1/4 chord, centerline, waterline)

empty_weight_CG_position = 0, 0, 0 // (feet) longitudinal, lateral, vertical distance from specified datum

 

max_number_of_stations =50

 

station_load.0 = "170.0, 41.0, -1.5, 0.0, Pilot" //Weight (lbs), longitudinal, lateral, vertical positions from datum (feet)

station_load.1 = "170.0, 41.0, 1.5, 0.0, Co-Pilot" //Weight (lbs), longitudinal, lateral, vertical positions from datum (feet)

station_load.2 = "510.0, 0.0, 0.0, 0.0, Crew" //Weight (lbs), longitudinal, lateral, vertical positions from datum (feet)

station_load.3 = "3840.0, 25.5, 0.0, 0.0, First Class" //Weight (lbs), longitudinal, lateral, vertical positions from datum (feet)

station_load.4 = "17850.0, 11.0, 0.0, 0.0, Coach 3-10" //Weight (lbs), longitudinal, lateral, vertical positions from datum (feet)

station_load.5 = "17850.0, -10.0, 0.0, 0.0, Coach 11-18" //Weight (lbs), longitudinal, lateral, vertical positions from datum (feet)

station_load.6 = "20230.0, -30.5, 0.0, 0.0, Coach 19-25" //Weight (lbs), longitudinal, lateral, vertical positions from datum (feet)

station_load.7 = "10000.0, 20.5, 0.0, 0.0, Forward Baggage" //Weight (lbs), longitudinal, lateral, vertical positions from datum (feet)

station_load.8 = "4000.0, -27.5, 0.0, 0.0, Aft Baggage" //Weight (lbs), longitudinal, lateral, vertical positions from datum (feet)

 

 

;Moments of Inertia

empty_weight_pitch_MOI = 18000000

empty_weight_roll_MOI = 5500000

empty_weight_yaw_MOI = 16300000

empty_weight_coupled_MOI= 0.0

 

[flight_tuning]

cruise_lift_scalar = 2.2

parasite_drag_scalar = 1.0

induced_drag_scalar = 1.0

elevator_effectiveness = 1.0

aileron_effectiveness = 1.0

rudder_effectiveness = 1.0

pitch_stability = 1.0

roll_stability = 1.0

yaw_stability = 1.0

elevator_trim_effectiveness = 1.0

aileron_trim_effectiveness = 1.0

rudder_trim_effectiveness = 1.0

[flaps.0] //Inboard Trailing Edge

type = 1 // 1 - tail, 2 - lead

span-outboard = 0.2 // 0.0 .. 1.0

extending-time = 25 // seconds

flaps-position.0 = 0 // degrees

flaps-position.1 = 0 // degrees

flaps-position.2 = 5 // degrees

flaps-position.3 = 15 // degrees

flaps-position.4 = 20 // degrees

flaps-position.5 = 25 // degrees

flaps-position.6 = 30 // degrees

damaging-speed = 260 // KIAS

blowout-speed = 300 // KIAS

lift_scalar = 0.15

drag_scalar = 0.55

pitch_scalar= 0.15

system_type = 1 //Hydraulic

 

[flaps.1] //Outboard Trailing Edge

type = 1 // 1 - tail, 2 - lead

span-outboard = 0.8 // 0.0 .. 1.0

extending-time = 23 // seconds

flaps-position.0 = 0 // degrees

flaps-position.1 = 0 // degrees

flaps-position.2 = 5 // degrees

flaps-position.3 = 15 // degrees

flaps-position.4 = 20 // degrees

flaps-position.5 = 25 // degrees

flaps-position.6 = 30 // degrees

damaging-speed = 260 // KIAS

blowout-speed = 300 // KIAS

lift_scalar = 0.05

drag_scalar = 0.35

pitch_scalar= 0.05

system_type = 1 //Hydraulic

 

[flaps.2] //Inboard Leading Edge Slats

type = 2 // 1 - tail, 2 - lead

span-outboard = 0.5 // 0.0 .. 1.0

extending-time = 4 // seconds

flaps-position.0 = 0 // degrees

flaps-position.1 = 0.5 // degrees

flaps-position.2 = 0.5 // degrees

flaps-position.3 = 0.5 // degrees

flaps-position.4 = 0.5 // degrees

flaps-position.5 = 1.0 // degrees

flaps-position.6 = 1.0 // degrees

damaging-speed = 260 // KIAS

blowout-speed = 300 // KIAS

lift_scalar = 0.05

drag_scalar = 0.05

pitch_scalar= 0.01

system_type = 1

 

DC10

[flaps.0] //Inboard Trailing Edge

type = 1 // 1 - tail, 2 - lead

span-outboard = 0.2 // 0.0 .. 1.0

extending-time = 25 // seconds

flaps-position.0 = 0 // degrees

flaps-position.1 = 0 // degrees

flaps-position.2 = 5 // degrees

flaps-position.3 = 15 // degrees

flaps-position.4 = 20 // degrees

flaps-position.5 = 25 // degrees

flaps-position.6 = 30 // degrees

damaging-speed = 260 // KIAS

blowout-speed = 300 // KIAS

lift_scalar = 0.15

drag_scalar = 0.55

pitch_scalar= 0.15

system_type = 1 //Hydraulic

 

[flaps.1] //Outboard Trailing Edge

type = 1 // 1 - tail, 2 - lead

span-outboard = 0.8 // 0.0 .. 1.0

extending-time = 23 // seconds

flaps-position.0 = 0 // degrees

flaps-position.1 = 0 // degrees

flaps-position.2 = 5 // degrees

flaps-position.3 = 15 // degrees

flaps-position.4 = 20 // degrees

flaps-position.5 = 25 // degrees

flaps-position.6 = 30 // degrees

damaging-speed = 260 // KIAS

blowout-speed = 300 // KIAS

lift_scalar = 0.05

drag_scalar = 0.35

pitch_scalar= 0.05

system_type = 1 //Hydraulic

 

[flaps.2] //Inboard Leading Edge Slats

type = 2 // 1 - tail, 2 - lead

span-outboard = 0.5 // 0.0 .. 1.0

extending-time = 4 // seconds

flaps-position.0 = 0 // degrees

flaps-position.1 = 0.5 // degrees

flaps-position.2 = 0.5 // degrees

flaps-position.3 = 0.5 // degrees

flaps-position.4 = 0.5 // degrees

flaps-position.5 = 1.0 // degrees

flaps-position.6 = 1.0 // degrees

damaging-speed = 260 // KIAS

blowout-speed = 300 // KIAS

lift_scalar = 0.05

drag_scalar = 0.05

pitch_scalar= 0.01

system_type = 1

[flight_tuning]

cruise_lift_scalar= 2.10

parasite_drag_scalar= 1.20

induced_drag_scalar= 1.10

elevator_effectiveness= 0.90

aileron_effectiveness= 1.20

rudder_effectiveness= 1.00

pitch_stability= 1.20

roll_stability= 1.20

yaw_stability= 1.00

elevator_trim_effectiveness= 1.20

aileron_trim_effectiveness= 1.00

rudder_trim_effectiveness= 1.00

[Flaps.0]

type= 1

span-outboard= 0.800

extending-time= 15.000

damaging-speed= 280

blowout-speed= 300

lift_scalar= 0.200

drag_scalar= 1.200

pitch_scalar= 0.000

system_type= 1

 

flaps-position.0= 0.000

flaps-position.1= 5.000

flaps-position.2=15.000

flaps-position.3=22.000

flaps-position.4=35.000

flaps-position.5=50.000

 

[Flaps.1]

type= 2

span-outboard= 0.990

extending-time= 5.000

damaging-speed= 280

blowout-speed= 300

lift_scalar= 0.200

drag_scalar= 0.900

pitch_scalar= 0.000

system_type= 1

 

flaps-position.0= 0.000

flaps-position.1= 5.000

flaps-position.2=15.000

flaps-position.3=22.000

flaps-position.4=35.000

beroun - The first thing I would check would be actual fuel. On your main aircraft selection screen, select your aircraft, and when the aircraft you selected appears and starts spinning, click on fuel and payload, and at a quick glance it will tell you if the plane is overloaded. Fuel is usually the cause for slow takeoffs, 6.7 lbs per gallon, it doesn't take much! Developers usually load these plane right up to the max. A lot of mine, that have given me problems, I have gone in on the aircraft cfg file and reduced the fuel amount to around 60% of what the original cfg says. That should help. By checking the fuel and payload, it might show you the difference in 2 aircraft and their performance.

Many thanks,

got the similar fuel loads in both about 30%. But noted that DC10 (long TO run) has many station loads in [weight and_balance] and changing these loads while FS running shuts down the FS. Strange, never happened to me before.

 

[WEIGHT_AND_BALANCE]

max_gross_weight= 575000.00

empty_weight= 267996.00

reference_datum_position= 0.00, 0.00, 0.00

empty_weight_CG_position= 0.00, 0.00, 0.00

station_load.0= 2400, 65.50,-5.00, 1.50

station_load.1= 2900, 65.50, 5.00, 1.50

station_load.2= 1000, 59.00,-5.00, 1.50

station_load.3= 2100, 59.00, 5.00, 1.50

station_load.4= 3200, 52.50,-5.00, 1.50

station_load.5= 850, 52.50, 5.00, 1.50

station_load.6= 2100, 46.00,-5.00, 1.50

station_load.7= 2050, 46.00, 5.00, 1.50

station_load.8= 1000, 39.50,-5.00, 1.50

station_load.9= 1250, 39.50, 5.00, 1.50

station_load.10= 2200, 33.00,-5.00, 1.50

station_load.11= 1450, 33.00, 5.00, 1.50

station_load.12= 2050, 26.50,-5.00, 1.50

station_load.13= 1700, 26.50, 5.00, 1.50

station_load.14= 1650, 20.00,-5.00, 1.50

station_load.15= 2000, 20.00, 5.00, 1.50

station_load.16= 3000, -15.00,-5.00, 1.50

station_load.17= 2450, -15.00, 5.00, 1.50

station_load.18= 1100, -21.00,-5.00, 1.50

station_load.19= 2000, -21.00, 5.00, 1.50

station_load.20= 2800, -27.00,-5.00, 1.50

station_load.21= 1000, -27.00, 5.00, 1.50

station_load.22= 2000, -33.00,-5.00, 1.50

station_load.23= 2150, -33.00, 5.00, 1.50

station_load.24= 1150, -39.00,-5.00, 1.50

station_load.25= 1700, -39.00, 5.00, 1.50

station_load.26= 500, 77.00,-3.00, 9.50

station_load.27= 500, 77.00, 3.00, 9.50

station_load.28= 1020, 56.66,-4.00, 9.50

station_load.29= 680, 56.66, 0.00, 9.50

station_load.30= 1260, 56.66, 4.00, 9.50

station_load.31= 1020, 36.31,-6.00, 9.50

station_load.32= 850, 36.31, 0.00, 9.50

station_load.33= 680, 36.31, 6.00, 9.50

station_load.34= 1200, 18.97, 0.00, 9.50

station_load.35= 1200, 15.97, 0.00, 9.50

station_load.36= 120,-10.64, 0.00, 9.50

station_load.37= 120,-10.64, 0.00, 9.50

station_load.38= 10220,-24.73,-6.00, 9.50

station_load.39= 10220,-24.73, 0.00, 9.50

station_load.40= 10220,-24.73, 6.00, 9.50

station_load.41= 1200,-45.07,-3.00, 9.50

station_load.42= 1220,-45.07, 3.00, 9.50

station_load.43= 8900, 14.00,-29.25,-2.80

station_load.44= 8900,-78.50, 0.00, 22.50

station_load.45= 8900, 14.00, 29.25,-2.80

station_load.46= 240, 87.75,-2.30, 9.50

station_load.47= 180, 87.75, 2.30, 9.50

station_load.48= 225, 86.75, 2.00, 9.50

station_load.49= 5500, -50.00, 0.00, 2.50

max_number_of_stations= 50

empty_weight_pitch_MOI= 28900000.00

empty_weight_roll_MOI= 15400000.00

empty_weight_yaw_MOI= 45100000.00

empty_weight_coupled_MOI= 401000.00

What stands out to me is, for the L-1011:

 

[flight_tuning]

cruise_lift_scalar = 2.2

 

You didn't provide the equivalent line for the DC-10.

 

That much cruise lift will considerably reduce rotation speed.

 

Nadlzfw

What do you mean "cannot rotate"?? Is it only a trim problem, a takeoff weight/Flap setting issue perhaps??

 

What DC-10 and L-1011? CLS or freeware ??

Thanks,

have increased the [flight_tuning] cruise_lift_scalar in both, since the aircraft were flying pitched up in cruise and 2.2 figure fixed it (from 1.0). When I mentioned cannot rotate, I meant that the aircraft did not get airborne when pulling the yoke for TO until the speed bilt up excessively high (DC10). But have played with the fuel loads and weights and both now take off ok. Or reasonably OK. And yes, these are both freeware from this site, MUCH!! appreciated. A real pleasure to fly with analog instruments, nice change from the simplistic glass cockpits.

Thanks all again.

I also suspect it is a 'trim problem' (ie: pilot error?). You need to input +2.00 pitch trim for L1011 and +3.00 pitch trim for DC-10 before takeoff roll to lift off earlier (ie: lower speeds). The flaps don't provide sufficient lift either. The cfgs are a mess for both (a joke!). Good luck.

Chuck B

Napamule

Most commercial airliners cruise at altitude with a nose-up attitude. Each one has it's own pitch at cruise. They need to do that for the proper AOA for the best lift for the aircraft's speed and weight. Even the F/A-18C has it's best range cruise at 42,000', 4° nose up, Mach .84.

Most commercial airliners are similar. Some amount of pitch, for certain Mach number at the optimum cruise altitude. The POH should say. You've artificially leveled the planes at cruise. Doing this will certainly affected the rest of the plane's flight regimes. Like take-off for example...

 

Pat☺

Thanks,

have increased the [flight_tuning] cruise_lift_scalar in both, since the aircraft were flying pitched up in cruise and 2.2 figure fixed it (from 1.0). When I mentioned cannot rotate, I meant that the aircraft did not get airborne when pulling the yoke for TO until the speed bilt up excessively high (DC10). But have played with the fuel loads and weights and both now take off ok. Or reasonably OK. And yes, these are both freeware from this site, MUCH!! appreciated. A real pleasure to fly with analog instruments, nice change from the simplistic glass cockpits.

Thanks all again.

 

beroun -At a glance, looking at both aircraft, L1011 looks like a typical weight and balance for station loads. Station loads 3 thru 8 for passengers and baggage amount to 73770 lbs, which could be reduced if you need to, but I don't believe you need to with the L1011 because you are getting good results with the takeoff on the L1011!

 

Looking at the weight and balance for the DC10, something just doesn't look right, you can't even easily identify passenger and baggage station loads? The L1011 has 8 station loads, the DC-10 has 49? Until you can find another DC-10 weight and balance configuration to compare to, I would say be satisfied with flying the L1011!!! I am sure there are other DC-10 downloads out there that you could download, just to check the weight and balance against the one you have! OR, replace the one you have!

 

Just a suggestion, when tweeking aircraft configs, you need to know what you are making changes to.

When I have a freeware download giving me problems, I print out the original aircraft config file, and then make my notes, as to changes I have made as I go along! That way, if I make a mistake somewhere, I can always go back to my original settings!

 

Good luck. Enjoy the L1011 and start looking for another DC-10, either to replace the one you have or to use for comparisons!

 

Rick

 

Here is a link I use for finding checklists. It says the DC10 should rotate at 155 KIAS

 

http://freechecklists.net/simchecklists.asp

Thanks all,

all thoughts are much appreciated. Always a learning point.

Peter

When trying out different settins to an aircraft config I often use double slash in front of the original value and enter my "new" value ahead of this. It makes it easier to find changes made and modify or restore values as required. eg. nav_proportional_control=20.000000//9.000000.

When trying out different settins to an aircraft config I often use double slash in front of the original value and enter my "new" value ahead of this. It makes it easier to find changes made and modify or restore values as required. eg. nav_proportional_control=20.000000//9.000000.

 

I like that, thanks. - Rick