A working 737 rudder trim panel

[Aerosim Solutions]

Hi all,
I have been continuing work on the radio box and this weekend I built a working rudder trim panel. I didn't make the fantastic face plate by the way, this was from Geremy at GLB flight products. I've used a small geared 50 rpm motor to turn a threaded axle and this moves a trunnion nut left and right. This is connected to a 10k linear potentiometer and the indicator pointer. The rudder trim knob has a cam that tilts a spring centered dual pole switch for changing direction. I don't think I will develop it as a product so copy if you wish!!!
PC, let me know if you want the plans, one for FDS??

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Cheers, Gwyn

[Nat Crea]

Very nice job Gwyn! Very...
Do you have plans to interface it?
(DC motor feedback is a little more painful than servo's...nothing Mr SIOC David couldnt do )

Nat

[fordgt40]

(DC motor feedback is a little more painful than servo's...nothing Mr SIOC David couldnt do )

Nat

Hi Nat

Already done  Here is a picture of my less elegant system!

[tennyson]

Damn, Gwyn,
That's a work of art. I wish I had a quarter of your talents,

Keep up the good work, mate,


Frank Cooper

[Nat Crea]

Already done

I was on the money hey David?
Nice job.
Its on my to do list...long list....

Nat

[fordgt40]

Already done

I was on the money hey David?
Nice job.
Its on my to do list...long list....

Nat

Give the man a free tallie or tinny so he can then veg out 

[Aerosim Solutions]

Cheers guys, what can I say David...great minds think alike lol!
I was going to use gears but then opted for a belt so that the belt can slip if the trunnion is accidently overdriven to the end of travel limits, it works well and the drive belt is just a stock O ring. There is a roller bearing concealed in the block that supports the main input axle, the photos can't show that but that makes the knob centering work well.
Nat I hadn't considered feedback from the sim, this was just to be a manual rudder trim adjuster, does the autopilot feedback to rudder trim? I guess it would during turns? My mate/customer and his brother have developed a simple interface software to control DC motors via a Phidgets control board. They have successfully tested it in auto throttle function of the PMDG NGX and this system will be used in my new TQ, more on that software later (If I'm allowed to spill the beans!)
Cheers Gwyn

[Nat Crea]

GDay Gwyn,

I guess you dont have to interface the motor if its position is pretty consistent (ie centre is always centre). You could get a way with just interfacing the pot to allow you to trim the aircraft in event of single engine failure,if that ever happens?

Nat

[Aerosim Solutions]

GDay Gwyn,

I guess you dont have to interface the motor if its position is pretty consistent (ie centre is always centre). You could get a way with just interfacing the pot to allow you to trim the aircraft in event of single engine failure,if that ever happens?

Nat

Hi Nat, that was my plan just to interface the pot to trim the rudder, no feedback. I should be able to span the pot through the full range assuming FSX has an input for rudder trim via FSUIPC and then the pointer on the scale will be accurate. I'm on the Worldflight team using Richard's awesome FDS 777 sim at FlightCity and I noticed it had a working trim knob but no indicator if I remember correctly. I'll have another look tonight to confirm it, I think the rudder trim panel is identical to the 737 apart from that weird brown colour!!!
Cheers Gwyn

[Nat Crea]

FDS 777 sim at FlightCity and I noticed it had a working trim knob but no indicator if I remember correctly

Richards 777 would be close to 3 years old now. I cant remember if his Rudder trim had the Servos installed...maybe. It was around the time they started to roll out
of the FDS Factory... SCos may remember.

Nat

[fordgt40]

Hi Gwyn, Nat

Both FSUIPC and Sim A have offsets for rudder trim. The rubber O ring was a great idea, I have to rely on software
I see we adopted slightly different ways to interface to the centre sprung rudder knob. Yours is the elegant mechanical solution 
I used a sprung to centre miniature toggle with a lever arm as in this photo.

Regards

David

[Aerosim Solutions]

Hi Gwyn, Nat

Both FSUIPC and Sim A have offsets for rudder trim. The rubber O ring was a great idea, I have to rely on software
I see we adopted slightly different ways to interface to the centre sprung rudder knob. Yours is the elegant mechanical solution 
I used a sprung to centre miniature toggle with a lever arm as in this photo.

Regards

David

Hi David, my toggle switch is also spring centered but to rotate the trim knob to the markers on the face plate determined that the cam had to have a little more free play around the switch. The spring that pulls the cam to center came as an after thought but it is simple and does the trick. It was fun designing this one but it took a full day to get it assembled and working correctly without issues. What a joy that it is for my sim and won't be going into a box for someone else!
Cheers Gwyn

[Jetcos]

The Flightcity B777 should have the functional Rudder Trim. Uses a servo.  Also has the cancel switch which centers the Rudder Trim with a push of the button.

[Aerosim Solutions]

The Flightcity B777 should have the functional Rudder Trim. Uses a servo.  Also has the cancel switch which centers the Rudder Trim with a push of the button.

Hi Steve,
We took the rudder trim panel out of Richard's T7 last night so I got to see how it is constructed - nice work btw! Unfortunately the unit has failed, the rudder trim knob still inputs rudder trim to SimA but the tape drive servo is not working and the white pointer is out of view off the scale. The trim indicators each side of the CCUs have also stopped working, we will look into it but electronics is not my field, we may need some help. Richard and Ken have been mates for quite a while and I help out as the FlightCity local mechanic, Richard originally approached me to build his sim after seeing mine but being part time it was a job for you guys!
Cheers Gwyn