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Hi Gwyn.
I am putting together a 737 cockpit, but having only ever flown a Twin Otter, I am having to learn a few new things!
Could you explain how the trim wheels interface with FS? They appear to have almost unlimited turns and I can't see how this motion is transferred to a 'trim up' 'trim down' action?
Hope you can help!
Regards,
TONY Plymouth UK
I don't know if anybody has actually interfaced the trim wheels themselves since trim is applied through a switch on the yoke. In real life you could trim the elevator by turning the wheel but it would be very tedious.
On the B1900s I was flying, there is both electrical trim, via yoke switches, and also a trim wheel next to the throttle quadrant. The idea was to use the electrical trim to get the trim close, then use the wheel to fine tune it. In the airplane I'm flying now, there is only electrical trim via the yoke, can't fine adjust the trim which is sometimes annoying, always try for the "let go and see what it does" method. I sometimes miss the old Beech. Why not get the Syteck Cessna trim wheel and modify that?
I found this on Bodnar's site:
Infinite Potentiometer
Quote:
Originally Posted by manhattan
Hi Tony,
I interfaced my trim wheels using pulse switches. You can find info on the pulse switches on Ian's site. Ordered mine from Mouser.. 3 or 4 dollars each or something like. I didn't like the idea of having the trim wheels there as an ornament..so interfaced them each to a pulse switch and FSUIPC. They work great and it's an easy mod. The only thing I dont have is a graduation needle to show where the trim is at, but Prosim has a scale that can be dragged and dropped in a convenient location for viewing.
Wow I am late on seeing this one, sorry Tony!
The way I have built my TQ's trim system - I have it on good authority that there are 45 turns "lock to lock" on the trim wheels of the Boeing TQ so I built in a reduction drive to drive a gear on which the trim indicators are mounted on. 45 turns of my trim wheels move the trim indicators along the scales which is about 65mm long. This movement is only about 50 degrees of rotation but the indicator gear and this gear also drives my trim potentiometer so all up, 45 turns of the trim wheels turn my trim pot 270 degrees, what a challenge that was to achieve!! When I trim on the yoke buttons the value will change in FS instantly. The FS trim value is transmitted to a Phidgets DC motor controller card which is reading my trim pot value. A DC motor will then rotate the trim wheels until all the values align. The custom software has acceleration and deceleration functions built in so it shouldn't hunt or mess about. We have proven it for driving the auto throttles on another TQ that I built, it works great but we have tested on the trim function as yet because my TQ is not yet wired up. My software engineer Thomas assures me it this is all "too easy" and simple to achieve. I will report more on this when it is finally assembled.
If you just want to achieve manual trim with unlimited turns on the trim wheels, make them rotate a rotary encoder should do the trick but the electronics guys would need to describe that one for you...
Cheers Gwyn
Hi Gwyn.
Great job for your trim wheel.
I'm working on my 737 TQ and I have motorised the handles by servo motor with Link2fs program and an arduino Uno. Now I must motorise my trim wheel like you with dc motor and I would like to know which script did you used for that.
Thanks a lot for your reply.
Jean-lou
Reunion Island
Hi Jean,
My custom C Sharp script was written by my Worldflight crew member and good friend Thomas. I don't really know how it works but basically it is designed to make the trim wheel indicators follow and match the Prosim trim gauge. When I trigger the yoke trim, the Prosim gauge moves and my wheels spin to move the TQ indicator. This indicator has a feedback pot and it is basically a loop control. Moving my trim wheels by hand does not trim the plane. The wheels spin and adjust all the time when the auto pilot is on, it is very cool but I can't help you with software or code unfortunately. Cheers Gwyn
Cheers Gwyn,Quote:
Originally Posted by Westozy
My apologies for my late reply, some prb with my internet.
Thanks for your reply. They made a great job for you, you are very lucky ;-)
I need a script for the TRIM wheel wich will work with my arduino card because I use LINKE2FS to run all of my throttle quadrant.
I use DC motor and if you have any informations on my script so tell me please :-)
May be you can give me any contacts who could help me on my script...
here my script :
#include <Servo.h>
Servo autotServo; // servo for my engine throttle 1
Servo autotServo2; // servo for my engine throttle 2
Servo autotServo3; // servo for my spoiler
int Data;
String AT;
int pos = 0; // variable to store the servo position
byte pinLed = 13; // LED for my parking brake
void setup() {
autotServo.attach(10); // KIOSHO
autotServo2.attach(9); // POWER HD
autotServo3.attach(6);
Serial.begin(115200);
Serial.flush();
Serial.println("W");
Serial.println("V");
Serial.println("q");
Serial.println("j");
pinMode(13,OUTPUT);
}
void loop() {
if (Serial.available() > 0) {
Data = Serial.read();
if (Data == 'W'){
delay (1);
AT = "";
AT += char(Serial.read());
AT += char(Serial.read());
AT += char(Serial.read());
AT += char(Serial.read());
int ATInt = AT.toInt(); // convert it to an integer
ATInt = (ATInt + 0);// Manual correction to suit servo zero.
ATInt = map(ATInt, +0, +100, 28, 120);//map the integer
for(pos =0; pos <180; pos += 1) // goes from 0 degrees to 180 degrees
autotServo.write(ATInt);
}//end of found "W"
if (Data == 'V'){
delay (1);
AT = "";
AT += char(Serial.read());
AT += char(Serial.read());
AT += char(Serial.read());
AT += char(Serial.read());
int ATInt = AT.toInt(); // convert it to an integer
ATInt = (ATInt + 0);// Manual correction to suit servo zero.
ATInt = map(ATInt, +0, +100,61, 119);//map the integer
for(pos = 0; pos < 180; pos += 1) // goes from 0 degrees to 180 degrees
autotServo2.write(ATInt);
}//end of found "V"
if (Data == 'q') {
delay (1);
AT = "";
AT += char(Serial.read());
int ATInt = AT.toInt();
if (ATInt > 0) digitalWrite(pinLed, HIGH);
else digitalWrite(pinLed, LOW);
}
if (Data == 'j') {
delay (1);
AT = "";
AT += char(Serial.read());
int ATInt = AT.toInt();
if (ATInt > 0) autotServo3.write(90);
else autotServo3.write(0);
}
}//end of serial read
}//
Everything work well, I'm very happy but my last step is the trim wheel...
So keep me notified if you have any contact for me :-)
thanks a lot..
kind regards