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Thread: FSX Stratojet Excalibur pitch problems?

  1. #1
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    Default FSX Stratojet Excalibur pitch problems?

    Hey guys so I've been using the Stratojet Excalibur plane on the steam version of FSX. However the plane's pitch isn't stable at higher and cruising altitudes, and I'm wondering if there's a way to solve this by changing anything in the aircraft cfg file? And if so, how do you do so?

  2. #2
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    With autopilot on at cruise level, if it's pitching up and down or 'porpoising', the pitch moment of inertia or MOI could be too high. Look for the [WEIGHT_AND_BALANCE] section in the aircraft.cfg, then look for the "empty_weight_pitch_MOI=" entry. Edit it as per the example below:

    Change:
    empty_weight_pitch_MOI=5020933.91000

    To:
    empty_weight_pitch_MOI=4020933.91000

    Then test again. If the porpoising has reduced, subtract another 1 from the MOI and test again until the porpoising stops.
    If the porpoising has increased, add another 1 from the MOI and test again until the porpoising stops.
    Tim Wright "The older I get, the better I was..."
    Gigabyte Aorus GA-Z270X-Gaming 7, Intel i5-7600k 3.80GHz OC'd 4.2GHz, NZXT X62 Kraken, 16Gb 3500MHz Ram, 1TB & 2TB Samsung Hybrid SSD's, LG DVDRW, NVidia GTX1050Ti 4Gb, Phanteks Enthoo Pro M case, CH Yoke & Pedals, Asus K272HL 27" Monitor, Windows 10 Pro x64

  3. #3
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    I fly the Stratojet Excalibur often, a favorite imaginary supersonic business jet with 2D wide aspect panel by Philippe Wallaert. Thank you, Philippe!

    I stopped the porpoising by modifying these two values, a somewhat simpler technique that yields good results on this and other planes that needed it, though the two values require testing. Every plane model is different. Be sure to make a backup copy of the original aircraft.cfg.

    [flight_tuning]
    elevator_effectiveness=0.9
    pitch_stability=3.0


    Last edited by ftldave; 01-15-2020 at 10:05 AM. Reason: change txt

  4. #4
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    Sorry for the late reply guys but thank you all for your replies, I appreciate it, I've been busy with uni past few days but I will test the aircraft now and see if things have changed

  5. #5
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    I've tried both methods mentioned above, but it doesn't change the pitching issues, is there another way to solve this issue?

  6. #6

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    You did not say which zip file name you are flying. There were 2 zips. One for FS9 and one for FSX.

    'stratojet_excaliber-1.zip' ......9,195 Kb, 01/19/2014........is for FSX.
    'sj_ex_2.zip' ......................12,743 kb, 10/22/2006.........is for FS2004.

    I have this jobbie. Did not work on sicne 2014. But for starters the MOI's are thus:
    empty_weight_pitch_MOI = 250000.000
    empty_weight_roll_MOI = 200000.000
    empty_weight_yaw_MOI = 200000.000
    empty_weight_coupled_MOI = 5000.000
    Try those. Also do you have this:
    [pitot_static]
    vertical_speed_time_constant = 1
    pitot_heat=1.000000
    I will fly it tonight. Got chores right now. Will report back tomorrow. The last time I flew it (2018) it was perfect as perfect can get - for being freeware. Heyart and Walert (spelling?) did top notch job on this one. That is why I mentioned FS9 -vs- FSX version. Get the right one then try it. Cheers.
    Chuck B
    Napamule
    Edit: And another thing: If you don't have the C-172 as your Default Flight (loaded at FSX start) then that WILL be your 'problem'. Believe it!
    Last edited by napamule2; 01-17-2020 at 03:43 PM.
    i7 2600K @ 3.4 Ghz (Turbo-Boost to 3.877 Ghz), Asus P8H67 Pro, Super Talent 8 Gb DDR3/1333 Dual Channel, XFX Radeon R7-360B 2Gb DDR5, Corsair 650 W PSU, Dell 23 in (2048x1152), Windows7 Pro 64 bit, MS Sidewinder Precision 2 Joy, Logitech K-360 wireless KB & Mouse, Targus PAUK10U USB Keypad for Throttle (F1 to F4)/Spoiler/Tailhook/Wing Fold/Pitch Trim/Parking Brake/Snap to 2D Panel/View Change. Installed on 250 Gb (D. FS9 and FSX Acceleration (locked at 30 FPS).

  7. #7
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    The zip file I have is the FSX one and I will have a look at the cfg file and see if I have them. If I do, should I edit the vertical speed time and pilot static sections, the ones you mentioned above?

  8. #8

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    Quote Originally Posted by rean001 View Post
    ...should I edit the vertical speed time and pilot static sections...
    No. vertical_speed_time_constant only controls the lag of the VSI.

    If you are playing with the MOI numbers you have to be careful when reducing them. Once you are below the FSX calculated numbers you can run into serious problems, especially when on ground.

  9. #9

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    Actually you do not have to do anything. I flew it and it is a little sluggish. Takes a while to get up to speed but otherwise it is PERFECT as perfect can get as is. Payware quality. Case closed.

    I believe your problem is not having the C-172 as your 'default' start up flight (when FSX first loads).
    Chuck B
    Napamule
    i7 2600K @ 3.4 Ghz (Turbo-Boost to 3.877 Ghz), Asus P8H67 Pro, Super Talent 8 Gb DDR3/1333 Dual Channel, XFX Radeon R7-360B 2Gb DDR5, Corsair 650 W PSU, Dell 23 in (2048x1152), Windows7 Pro 64 bit, MS Sidewinder Precision 2 Joy, Logitech K-360 wireless KB & Mouse, Targus PAUK10U USB Keypad for Throttle (F1 to F4)/Spoiler/Tailhook/Wing Fold/Pitch Trim/Parking Brake/Snap to 2D Panel/View Change. Installed on 250 Gb (D. FS9 and FSX Acceleration (locked at 30 FPS).

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