Hi! Needing some weight and balance figures for a McDonnell Douglas F15J aircraft.

I am trying to check the weight and balance information I have for a McDonnell Douglas F15J. Seems like every F15 I download, the aircraft.cfg is identical (not just weighting, everything is identical) to what I have. If you should have an F15 that is flying without issues, could you please share the weights you are showing in your aircraft.cfg for the following?:

empty_weight_roll_MOI=

empty_weight_pitch_MOI=

empty_weight_yaw_MOI=

empty_weight_coupled_MOI=

This is my last step in trying to figure out why this aircraft is taking a nose dive on a 90* turn with the Autopilot engaged! I would like to compare your figures with what came with my aircraft. If they are close, which I have my doubt, I will be sending this nice aircraft to

file 13!

PLEASE, I am not looking to debate anyone on why I should or shouldn't be messing with these items. I am just requesting (4) figures for the above aircraft.cfg entries!

Thanks in advance! Rick :cool:

Will this work? From the IRIS F-15E Strike Eagle.

[weight_and_balance]

max_gross_weight = 81000.000

empty_weight = 36500.000

reference_datum_position = 0, 0, 0

empty_weight_CG_position = 0, 0, 0

empty_weight_pitch_MOI = 250000.000

empty_weight_roll_MOI = 120000.000

empty_weight_yaw_MOI = 120000.000

empty_weight_coupled_MOI = 0.000

max_number_of_stations = 5

// station no. Weight (lbs), longitudinal, lateral, vertical positions from datum (feet)

station_load.0 =200.000000, 23.290000, -1.110000, 0.740000, Pilot

station_load.1=200.0000000, 0.000000, 0.000000, 0.000000,WSO

station_load.2=0.0000000, 0.000000, 0.000000, 0.000000,Payload Weight

CG_forward_limit= 0.000

CG_aft_limit= 1.000

No problems with 90 degree turns on autopilot!

Thanks Charlie! Your Roll and Yaw values are considerably less than mine, which is what is fighting me right now. I am going to try your figures to see if it helps. Also,, my coupled MOI was 1300. where you say yours is 0.000. I have several fighter jets which have 0.000 but I also have 2 that have values shown?, I'll leave that field be for now!

Thanks Charlie, do appreciate it!

Rick :cool:

Well, Charlie, it worked for a while, the change in yaw and roll didn't help, so i changed the coupled value to 0.00, and I thought I had it, worked great until I went to turn to the base leg, and down she wanted to come! She now resides in "File 13!"

Charlie, when you get a chance, no rush, do you have a file name, and where you downloaded your F15 from? I haven't given up on the F15 just yet. Yours does look nice and you are giving me a "positive" on how it flies!

Thanks again for your help! - Rick :cool:

Well, Charlie, it worked for a while, the change in yaw and roll didn't help, so i changed the coupled value to 0.00, and I thought I had it, worked great until I went to turn to the base leg, and down she wanted to come! She now resides in "File 13!"

 

Charlie, when you get a chance, no rush, do you have a file name, and where you downloaded your F15 from? I haven't given up on the F15 just yet. Yours does look nice and you are giving me a "positive" on how it flies!

 

Thanks again for your help! - Rick :cool:

FSX - FSX Modern Military FSX McDonnell-Douglas F-15E's of Railroad Valley

[ Download | View ]

Name: f-15e_rrv_jt.zip

Size: 58,047,882 Date: 07-31-2014 Downloads: 2,423

FSX McDonnell-Douglas F-15E's of Railroad Valley. This standalone full package of a modified and upgraded version of Iris' F15E Strike Eagle. It sports the tail codes of the Aeroworks Flight Centers in Railroad Valley, Nevada. The package includes two schemes in different configurations, updated autopilot, differential brakes and various other upgrades and changes. Incorporates popup FSX native radar for AI and multiplayer aircraft. Updated by Jason L. Terry.

Charlie - Okay, downloaded the Railroad Valley F15 and all was "Dead Nut," both altitude and airspeed!

Great download, thanks for steering me over to that download! Now, I am done for a while (I hope)!

Rick :cool:

weights you are showing in your aircraft.cfg for the following?:

Data from my FlightGear F-15 (http://zaretto.com/F-15) which is based on real reports and wind tunnel data; so I have a fairly high confidence that these numbers are right.

Aircraft Metrics

Aerodynamic Reference Point x=10.63M y=0.00M z=0.22M

Aircraft CG x=10.23M y=0.00M z=0.22M

Wingspan 13.05M

Wing Area 56.49 M2

Wing Incidence 0.00 DEG

ClMax 1.73 ND

Mass and balance

Empty 28000 LBS

IXX 28700 SLUG*FT2

IYY 165100 SLUG*FT2

IZZ 187900 SLUG*FT2

IXZ -520 SLUG*FT2

The above is an extract from the detailed data report http://www.zaretto.com/sites/zaretto.com/files/F-15-data/F-15-Aero-ZDAT-AED-201602-20181029141344.pdf - this PDF compares the results of OpenVSP against the WindTunnel data - however it has all of the details you should need.

Thanks, Richard, but I have solved my problem by giving up on the freeware downloads that were not cooperating and downloading the file recommended by mrzippy and all is good. I did enjoy that site that you included and was impressed by the pictorial footage of the F15! Great pics and fantastic graphics!

Thanks again for responding to my thread! Have a nice day! Rick :cool: