B747-400 Autothrottles :what do I need ?

[Gerard]

Hello everybody,

For my throttlequadrant I would like to include an autothrottle system.

I have some questions :

1 Is the 4 motor servo kit enough with the software ?
2 A friend of mine tried to make it himself, but he ended up with burned servos.
Because the autopilot is constantly adjusting the leverposition to maintain the
selected speed, the power was constantly changing on the servos and therefor
they where getting so hot that they got burned.
How can I avoid that ?

Thanks in advance for helping, :)

Gerard

[imported_Rob's 747-400]

Gerard,

I have recently completed construction of functional autothrottles for my 747-400 simulator. It was NOT an easy task! Mine are 100% constructed from the ground up and do not use any real components... and in fact if I had used original parts, the servo setup that I used would simply not have had the power to move the real levers. Are you planning on modifying OEM units, or constructing your own?

I spent around 3 months and $400+ investigating different servo units and setups; and for my system eventually settled on the singularly MOST powerful servo units available in the Radio Control world today... the HiTec 815BB, Sail-Arm units; which produce several pounds of force. These units cost around $60 a piece, and in my setup are being run at the very top of their input voltage specification at around 6.5 VDC.

When the Servos operate I find that they produce an impressive 2 Lbs force at the very top of the throttle levers; which is perfect for my unit... however I believe there is no way these units would have the power to move the heavy OEM mechanisms.

I am attaching several photos which show the development of my AutoThrottles and my sim... and you can see how the units have been mounted and actuate the throttle levers through heavy duty R/C control rods and balljoints.

Note that I bypassed the power circuit of the Phidgets 4-Servo controller, powering the units directly from a 12 Amp PSU. If you try to run large servos directly from the Phidget you'll probably end up 'cooking' it. :eek:

I'd be pleased to provide additional detail on construction methods and setup, etc. to anyone who's interetsted. I also want to add that my system only works thanks to an INCREDIBLE piece of software written by fellow simmer Alan Dyer... THANKS VERY MUCH, Alan!

Regards,

Rob.
Orlando, FL

[phidgets]

I also want to add that my system only works thanks to an INCREDIBLE piece of software written by fellow simmer Alan Dyer... THANKS VERY MUCH, Alan!
Glad to hear the software did the trick for you!

NOTE: Rob is talking about our software which is currently free on our site, FS2Phidget.

Here's the link:
http://www.phidgetsusa.com/fs/fs2phidgets/flight_simulator_FS2Phidget.asp

Matt

[Gerard]

Thanks Rob,

Your info has helped me a lot.

I now know what a need to make the autothrottle system work and with the controller and software and extra strong servo's it should work.

Btw , incredible looking cockpit.

Regards, :)
Gerard

[imported_737nut]

How do you keep the throttles synchronized? Example, autothrottle on, a/p enguaged , you a/t disc and manually fly your approach, you have a goaround and A/T kicks in again. How does the servo take back over the throttle movement?
Thanks,
Rob

[imported_Rob's 747-400]

Rob,

Hopefully you will find all the answers in a "How To" guide for AutoThrottles, that Matt will be uploading very shortly... watch this space!!!

If that does not address all your questions I'll be happy to address any additional feedback via the Forum or email.

Regards,

Rob.

[imported_Nihad]

Hello Rob,

A very impressive flightdeck u have build and your throttle audrant are deff. the best they made me buy the phidgets enocders right away as I have bin brain storming on this for so long finally to see a setup that works and looks less complicated.
The only question I have is about something u wrote Note that I bypassed the power circuit of the Phidgets 4-Servo controller, powering the units directly from a 12 Amp PSU. If you try to run large servos directly from the Phidget you'll probably end up 'cooking' it.

Could u please tell me or show me what I need to do so I wont cook it up and where I can find those slider pots (100K I guess u use) and the 12 amp PSU.

Thank u sir,

Regards,

Nihad

www.allush.net (needs an update)

[Farrokh]

Hi - I have bought the original -200 throttle quad, complete with AT motor, gears, chains all intact - does anyone know where I can get any info on how the OEM th quad works? for eg, is ther a clutch that connects and disconnects the levers from the AT motor.., etc - enclosed some images

thanks!
Farrokh.