B-737 Trim rate ( FIX )

  • Is there an easy way to increase the trim change rate?, I feel that the 737 trim with flap is just too slow to enable a comfortable trimmed state with speed, power and flap changes in the approach. I’d like to increase mine by about 4 X with flap. Is there a line of code that can be adjusted?

    I understand the 737 trim rate with flaps up is reduced but I think the current simulation trim rate on the approach doesn’t work.


    The 737 trim wheels look too slow.

  • Is there an easy way to increase the trim change rate?, I feel that the 737 trim with flap is just too slow to enable a comfortable trimmed state with speed, power and flap changes in the approach. I’d like to increase mine by about 4 X with flap. Is there a line of code that can be adjusted?

    I understand the 737 trim rate with flaps up is reduced but I think the current simulation trim rate on the approach doesn’t work.


    The 737 trim wheels look too slow.

    It seems normal for me but it may be due to my unfamiliarity with Boeing, you can try to change it in the B737's tmd folder, search for "compensator" and edit with a special editor and try to change I do not guarantee if it can be changed easily but if you edit save the original file before editing.


    Regards,

    Lucas

  • This is what I did in the gc-map config file in the documents folder, added a .5 to the Sign and it def feels better


    <[tmchannelmap][element][28]

    <[string8][FunctionID][ElevatorTrim]>

    <[string8][InputID][Pov 0 Up]>

    <[uint64][DeviceUniqueID][1468347801101187030]>

    <[string8][DeviceIDString][HOTAS Cougar Joystick]>

    <[bool][IsDigital][true]>

    <[bool][IsValue][false]>

    <[float64][Sign][1.5]>

    <[float64][Direction][1]>

    >

    <[tmchannelmap][element][29]

    <[string8][FunctionID][ElevatorTrim]>

    <[string8][InputID][Pov 0 Down]>

    <[uint64][DeviceUniqueID][1468347801101187030]>

    <[string8][DeviceIDString][HOTAS Cougar Joystick]>

    <[bool][IsDigital][true]>

    <[bool][IsValue][false]>

    <[float64][Sign][-1.5]>

    <[float64][Direction][1]>

    >

  • Hi Rairic, I gave that a go, does it make the joystick more sensitive?


    I got the 737 trim more the way I want it by changing the line in // pitch trim

    from

    <[float64][Speed][0.04678]>

    to

    <[float64][Speed][0.13678]>


    The trim wheel spins faster and the Aero 737 gets to the desired trim BEFORE the whole balance has changed again.


    If anyone wants to try it // pitch Trim is after // yaw damper and // nosewheel steering and before // aileron trim and // rudder trim in b737.tmd.

    It is near the top of the file, here is where it lies in notepad.

    Maybe try it for a day or two?, (remember it is the control column that sets the attitude, the trim then unloads the control column).


  • Overloaded

    Changed the title of the thread from “Trim rate” to “B-737 Trim rate ( FIX )”.
  • It would be nice to find a way to fine tune the roll rate so it doesn't fly like an F-16

    Is there any guide to adjusting the .tmd file? say in the advanced user generated aircraft or scenery programs. I don’t have any of the required expensive graphics software so I didn’t try them.

    I tired looking at the .tmd program lines for any obvious numerical values but I don’t see many obvious on or off options like (zero) and (one) for example. I got the default pitot heat turned off for realistic ground movement but I cannot get the recent unwanted autothrottle-on on the autopilot panel sorted.

    I don’t know C++, getting into BASIC was easier forty years ago.


    I thought the roll was just me! Could it be that the Aero 737’s basic inertia is way out? I cannot do a smooth and controlled flare either.


    The 737 seems like the unloved child in the family. Everything goes into Airbus culture which turns me off completely (shame about the MAX).

  • Looks like the 737 is using both ailerons and spoilers irrespective of speed. Lame.

    I cut the ailerons/spoliers travel in half with this modification in the custom 737 gc-map I use:


    <[tmchannelmap][element][82]

    <[string8][FunctionID][Aileron]>

    <[string8][InputID][X]>

    <[uint64][DeviceUniqueID][1468347801101187030]>

    <[string8][DeviceIDString][HOTAS Cougar Joystick]>

    <[bool][IsDigital][false]>

    <[bool][IsValue][false]>

    <[float64][Sign][0.5]>

    <[float64][Direction][1]>


    It feels pretty good in the 150-200kt range but you lose a bit of roll responsiveness on short final below 135kt.

    Considering this is a Frankenstein plane there's nothing wrong with landing at 140kt and flaps 30.

  • Modifying the control assignment will cause all kinds of trouble later on. Why don't you edit the airplane itself? The tmd file of the 737 contains simulated aileron actuators that have a deflection value. These could be reduced for starters.


    The correlation of aileron deflection over speed needs to be a constant and so does the spoiler deflection as far as I know. This is a fly by cable aircraft with hydraulic assistance. When you rotate the control wheel all the way you will get full aileron deflection regardless of speed (as long as the actuators can handle it). Only a fly by wire aircraft changes the control throws as speed changes, e.g. to keep the roll rate constant.


    Unless they actually have a aileron lock out at high speed? Then why have I never heard of that in the 737

  • I don't remember being able to pull 6 aileron rolls at low altitude in the milviz 737-200 in P3D 8o

    I get your logic but nobody has a force feedback yoke that can actually limit control surface movement vs speed (also no force feedback in the game) so it has to be simulated in the code right? The 737 experience should be all about wrestling the yoke on final and that's just not there at the moment.

  • I don't remember being able to pull 6 aileron rolls at low altitude in the milviz 737-200 in P3D.

    Also nobody has a force feedback yoke that can actually limit control surface movement so it has to be simulated in the code right?

    The real aircraft has artificial feel because the control forces on the yoke would be non existent due to the hydraulic assistance... So in the real aircraft you don't actually feel the actual control forces unless the hydraulics fail (which has happend but is an emergency situation, non standard).


    I prefer having the physical controls match the controls I see in the cockpit. Sure you could fake a force simulation but that would make the controls sluggish and delayed as you can feel for yourself in "other sims". This takes away the direct and connected nature of the Aerofly simulation and you'd not feel like you are actually flying.


    The force feedback simulation on joysticks still has a long way to go. There are just too few available and affordable devices out there. Otherwise we'd love to add a realistic force feedback simulation that does both: 1:1 control deflections, 1:1 equivalent forces felt. With the typical spring to neutral you can never get the forces right, so you're better off at least having the control deflections correct instead of having neither force or deflections accurate.


    Instead of trying to fix one issue by adding a simulated force to try and limit the pilot inputs (like a fly by wire would do) we should take a look of why the physics allow such high roll rates and fix the source of the issue. Not add layers on top to hide it. It could be that the aileron deflection is just too large or that the roll stability is too small. We can increase the inertia, reduce the amount of lift loss by the roll spoilers, reduce aileron effectiveness and a lot more.

  • Rairac,

    I tried your gc map mod with 0.1 on aileron and 0.3 on elevator and together with my trim rate increase I think I have a much nicer 737 now, a 737 that does what I want rather than one running away from me.

    I'll try to get a similar result in just the 737.tmd as Jan suggests.


    A mobile-like 3 independent axis sensitivity menu would be nice. ....oh include trim rate too!


    Thank You Both.