B-25 Nose up AGAIN.
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Thread: B-25 Nose up AGAIN.

  1. #1

    B-25 Nose up AGAIN.

    Hello again everyone, hope your all well.
    Now I've posted on this before and I am still scratching my skull on it. Whenever I try to fly any of the B-25s I cannot get the nose down, even with the stick full forward. It even does it in the official Firepower install, but only on the B-25s. Never used to. No other plane does it. I've calibrated my flight stick and my old one and it even did it on that. Any one else have this issue at all. Any pointers would greatly appreciated.

    Cheers Gordy.

  2. #2
    Assuming it's okay on 'other AC'?

    If so, I'd think it's the CoG that is too far forward. But, it also depends on who built the model, and where the CoG (Center of Gravity) was located for the model.
    The CoG can be adjusted in the Aircraft.cfg. Usually, CoG is located 1/4 to 1/3 rearward of the wing root.

  3. #3
    Thanks Crossram, I'll try and see what I can do. How would I edit said file? Which line etc. I'm a novice at this but learning

  4. #4
    [fltsim.0]
    title=B-25C
    sim=B_25
    model=b_25c

    [fltsim.1]
    title=B-25J
    sim=B_25
    model=b_25j

    [fltsim.2]
    title=B-25H
    sim=B_25
    model=b_25h
    [General]
    editable=0

    [WEIGHT_AND_BALANCE]
    max_gross_weight=34000.000000
    empty_weight=20300.000000

    reference_datum_position=19.900000,0.000000,0.0000 00
    empty_weight_CG_position=-17.500000,0.000000,0.000000

    max_number_of_stations=50
    station_load.0=180.000000,-10.100000,0.750000,3.000000
    station_load.1=180.000000,-10.100000,-0.750000,3.000000
    station_load.2=180.000000,-2.300000,0.000000,0.000000
    station_load.3=180.000000,-37.600000,0.000000,1.000000
    station_load.4=180.000000,-14.300000,0.000000,0.000000

    empty_weight_roll_MOI=61881.000000
    empty_weight_pitch_MOI=55159.000000
    empty_weight_yaw_MOI=113121.000000
    empty_weight_coupled_MOI=0.000000

    CG_forward_limit=0.000000
    CG_aft_limit=1.000000

  5. #5
    Member sixstrings5859's Avatar
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    Have you used the trim function ?

  6. #6
    This is what seems relevant to me......?

  7. #7
    Hello Scott, to be honest I really don't think it's the problem here as when I use the joystick after it removes the setting on the trim in the game. It does it on Firepower, stock CFS3 instal, and ETO. Never used to for some reason it just started doing it and this is one of my best planes. It uncannily nose up mate, unnaturally so to me. Something's not right. Bet it something simple too!

  8. #8
    The CG Forward and CG aft looks like it might be the line I'm after but that's just a guess from me.

  9. #9
    Hmm...are those the stock B-25s?

    reference_datum_position=19.900000,0.000000,0.0000 00
    empty_weight_CG_position=-17.500000,0.000000,0.000000

    Won't say for sure, but those entries look a little odd. To me, anyway.
    When CFS3 first came out, one of the first statements I made was...wonder what drunk made the 25s??

    Yeah, the CoG entries look okay...

    CG_forward_limit=0.000000
    CG_aft_limit=1.000000

    But, the reference_datum 19.9, and the empty_weight_CG at negative 17??

    I'll look at mine, and get back...

  10. #10
    Yeah, that's the stock 25s. I'll give mine a shot, and see what it does...just for kicks.

  11. #11
    Okay thanks, let me know how it goes. I think this is the stock ones. Yeah maybe the guy was drunk!! Don't know if anyone else has had this problem?

  12. #12
    Well, besides being a little nose heavy (no bomb load), it flew straight. Up/down movement okay, so you might have something else going on.

    Does it nose up, only with bomb loads, or including no bomb loads? What 'realism' setting do you use?

    Yup, sitting in that cockpit, makes ya wanna....puke!

  13. #13
    Hi Crossram, yes I fly with bombs/Rockets etc for any given mission. The nose up is unreal, makes the plane unflyable, it's probably something simple but I've had this problem before. It does it on every install eto stock etc, so it has to be something I've done possibly? Graphics card settings maybe?? Maybe I have too much anti-aliasing or some other setting. I will try setting resetting them all for this particular install. I reckon it's got to be something I've set somewhere. I'll retrace my steps and let you know. Appreciate your help mate. I gather you really don't like that cockpit!! Gordy!

  14. #14
    I use hard realism settings also. Gordy

  15. #15
    Do yo have in warning notices in the top right of the screen? I usually experience the nose doing this when I get the airplane is in an overspeed condition. Nose will not go down until the speed is bled off. I have had it happen with all the B-25s in CFS3

  16. #16
    I've always had the nose go up with the stock B-25H
    so I press 'Ctrl A' for auto-trim and she slowly
    levels out and behaves.

  17. #17
    Quote Originally Posted by Gordywill View Post
    I use hard realism settings also. Gordy
    Okay...if I understand all the workings, if using hard realism settings, you 'must' manually set trim. So, just like in the real thing, trim gets set near, or at 0 (neutral), before T.O..
    Not gonna write a book on it, but without using 'auto-trim', your forced to adjust trim, before moving an inch. Then...what's that old saying...fly the dang airplane! Seat of your pants stuff, and once upstairs, you adjust the trim for easy yoke. That's regardless of empty, or full load.

    Guessing the trim entry, in the airfile, or the CoG stuff, isn't right. So, when you climb in, trim is way off, so you get nose up.

  18. #18
    Also remember that manual trim is not a "set it, and forget it" proposition. Changes in speed and altitude have an effect on the trim needed for hands off flying. I have the different trim controls set for the toggle switches at the base of my HOTAS. Very handy to set up a steady climb out, or decent once you find the proper rudder/aileron cross-control combination to keep things going straight.
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  19. #19
    Yup! It's all a balancing act.

    This might help...hit the Z key, and it shows the trim settings. On the B-25s, elevator trim is -100!

    Simply adjust the elevator trim, and go for it. Your looking for neutral 'pressure', or forces, on the yoke.

  20. #20
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    Quote Originally Posted by crossram View Post
    reference_datum_position=19.900000,0.000000,0.0000 00
    empty_weight_CG_position=-17.500000,0.000000,0.000000
    if it helps to reduce extreme amounts of trimming, I would think the empty weight CG position is the parameter to edit. Try bringing the CG position forward from -17.5 to -16.5 and see what happens. Don't forget to delete the bdp.

  21. #21
    Hello all,
    Sorted it! Now I never had this problem till recently, something just niggled at me so I reset all of my Nvidia graphics settings in the control panel, and bingo! Good as gold no nose up whatsoever flies like a dream! Thanks all of for the input on this I very much appreciate it and the points mentioned are an education to me for future reference.Might have been the anti-alias settings or something I really don't know but it worked a treat.

    Thanks again . Gordy.

  22. #22
    Kurier auf Stube...pauke! NachtPiloten's Avatar
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    Icon26 COG

    The fueled COG is 17.85% and 19.9 unfueled, which are pretty forward so not sure why you would get a nose up situation. But there are some other quirks in the airfile that seem off. To redo the COG one could reset the model and try. In the realism options, the flight model difficulty is set at what? Try hard if it is not this level to begin with. Also, have you tried to trim the elevators? Finally, is the game patched to 3.1a?

  23. #23
    I am very confused why resetting nvidia settings would have any effect. I suspect it may have been a coincidence that the problem went away after that. My 2 cents - the stock FMs aren't worth saving in the first place. If you're going to be editing files anyways, go for mudpond or AvHistory FMs to swap in and get something that flies right rather than trying to fix something as badly broken as any of the stock FMs.

  24. #24
    Yea, what he said just above me!
    John
    (DR/ MAW/ ETO/ PTO Textures)

    Keep it coming!

  25. #25
    Quote Originally Posted by NachtPiloten View Post
    The fueled COG is 17.85% and 19.9 unfueled, which are pretty forward so not sure why you would get a nose up situation. But there are some other quirks in the airfile that seem off.
    Personally, I'd question those numbers, especially for the B-25s. Forget bomb loads, and the like. But, it takes fuel on board, other than empty CoG. B-25s CoG is at the main spar, and all the normal wing fuel cells, are right with that main spar. That means...empty 'flying wt w/fuel', would remain pretty near the CoG. Anyway, I'll leave it at that. Yep, FM needs some help.

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