trim

[Roland]

I agree, Very nice mechanics.

For elevator trim in FS9 or FSX, it is hard to make it behave like the real world trim, as FS build the trim function for mechanical joysticks, which have their zero force setting always in center position. So when adjusting trim, FS actually adjusts a bit of elevator offset, and the stick can be brought back to the center while the plane will be flying level with the extra elevator ofset. Not exactly like the real world trim.
See also http://www.fs-force.com/help2/trim_system.htm. To make it more realy world, Dirk modified the trim by intercepting the pilot trim from reaching FS, and only use it to shift the zero centerforce position of the yoke forcefeedback system.

I have also experimented a bit with force feedback trim, and you need a fair bit of experimenting to see what works best for your setup.

Roland

[AndyT]

I would place the other pot on the plate and connect it to the motor screw. Then when the motor adjusts, so does the pot. You can use the signal in a feedback loop to control the position of the plate that way.
Turn the trim wheel and the plate moves.

Wonderful design.

[hercules]

Thanks a lot for all replys. Nice to see the big interests in this meachanics My friend marcus has all the needed machines on his job and he support me in a great way

Yes, i believe that a second pot is what i need, but there is a big problem. The second pot would be linked to the trim-offset of the fs! The first pot is linkend off course to the elevator-offset.

As far as good, but the first pot (elevator) does register all movements of the columns....also that movements that was initiate from trim motor. So two commands will send to FS at same time...one from each pot.
In other words....when the trim moves the column...the elevator and the trim would move on the stab, because both pots turns and change both offsets.

I hope you unterstand what i mean....

Regards

Thomas

[Roland]

I know it is a bit confusing. The result will depend a bit on the sensitivity setting of the FS-trim value to amount of motor drive and resulting plate shift. As I mentioned, FS does not correctly deal with elevator trim. I'd say, try it out and do some experimenting with sensitivity. You could also do it as Dirk described, and make the the up/down trim switch act on the motor only, not to FS, and only link the yoke rotation potmeter to elevator control in FS.

[hercules]

Using only the elevator could be a problem, because i couldn´t setup the correct Takeoff-Trim due to the missing trim indication inside FS.

I think about using both potis, one linked to elevator and the other to the trim offset, but this with dissabled trim-effects in the aircraft.cfg.

So i would have both: Climb/ Descent with elevator via the elevator pot and trim indication with the trim pot within Project Magenta without effects to the aircraft.

Could this work?

Thomas

[dc6driver]

Hi Thomas,

Very nice work. I was wondering if you could post a few pictures detailing the threaded rod portion specifically where the rod goes through the bearing and the connection to the electric motor.

Fritz

[Roland]

Disabling trim in the aircraft config? Haven't tried that one. Interesting. Not sure how autopilot is going to behave then, since A/P ALT is controlled via trim, and the joystick input is disabled in A/P mode.

[hercules]

Hi,

I found a solution for the problem! Its so easy that i can`t believe that i ditn´t saw it sooner.

The elevator pot is a rotating pot, that is connected to the column via a flexible arm. But the pot itself was mounted to the main wood-plate far away from the middle section of the coulmns. Now i changed its position direct on the moving trim-plate and the flexible-arm is mounted to the middle (shorter) column arm. You know this arm from my pictures!

When i now push or pull the column, the elevator-pot does turning like before! But when i now move the trim plate to the correct trim-position, the elevator pot goes automaticaly back to its center-position, since its base plate is the trim-plate. In other words, the trim plate neutralize the pior column movement, because the trim movement is always the opposite direction of the prior column movement. I know...its difficult to understand, since my english is strange, but will upload pictures as soon it is ready for a photo-shooting

From now i can move the trim mechanics complete independently. The one an only "Bug" is, that the column position of a real aircraft does not change during trim action! But my construction does it....

Is this a reason to cry??

Nice sunday to you

Thomas

[rsandor]

Hi Thomas,

I have an idea how to overcome the problem of simultaneous movement of pitch by both potmeters. What if You mount the pitch potmeter to the previous position (where it was originally), and replace the trim potmeter with a stereo one. Now if you connect the second Chanel of the stereo potmeter in parallel with the pitch one (maybe with some current reducing resistors on both ends), to result pitch down when the other Chanel on the same potmeter commands pitch up trim. I`m sure that some experimenting with resistor values is a must (too small values will result in over steering, and vice-versa), but... Is this understandable, or I have tho draw a quick schematic?

Robert

[hercules]

Hello all,

thanks for the tip with the stereo pot, but as i wrote before, i found a solution that is much easier as you can see on the attached pictures!

i made some more detailed pictures now.

On picture e.jpg you can see the arm that is connected to the elevator-pot an the middle column pipe. When i push/ pull the column this arm moves the pot forward/ backward. The force on on coulmns i allways neutralized when the position of short part of the arm its 100% vertical. When i push the column the angle of the arn moves some degrees. Now i have to move the trim-plate as long till the arm i vertical again. Just now i can leave the hands from the yoke without lost controls. Its a great feeling to feel the force change during trimming.. You can also see the slider pot for the trim.
Next step ist the trim wheel. I use a multiturn pot for it and i let comepare the values of the trim-/ Wheelpoti with sioc! When the trim pot value i different than the wheel pot, the trim motor moves until the values are not different.

Thomas

Thomas