A/P Panel and Servo Connections

[AlpDmr]

Hi all, we are working on a AirCraft harness project and I couldn't understand some connections/devices.
We are using SV-AP-Panel for AutoPilot functionalities and two SV52L servo motors for Pitch and Roll axis.

There is an AutoPilot wiring diagram on Dynon system like below (We'll use both Trim Up/Down (Pitch) - Left/Right (Roll) for Pilot and Co-Pilot). So,
1 - We need to wire the 3,4,10,11,5,6,12,13 pins for Pilot and Co-Pilot yoke switches and 7,8,14,15 pins for Pitch and Roll motors in AP-Panel. Is it CORRECT?

2 - I assume that Pitch Trim Motor and Roll Trim Motors are Pitch SERVO and Roll SERVO. Is it CORRECT?
3 - If my assumptions in first 2 lines are correct then based on below drawing, I need to wire connection between Servo Motors and SV-NET-HUB (my choice) with 4 wires. Is it CORRECT?

4 - Motor 1 (Pitch Trim Motor) and Motor 2 (Roll Trim Motor) should be connected to the SV-AP-PANEL also like below drawing. Is it CORRECT?

If all my all assumptions are correct above, I don't understand that, While SERVO Motors have only 7 wires (and while three of them for Power, Ground and Disconnect and other 4 wires for SV-NET connection (1A/1B/2A/2B) ), which pins of SERVO Motors should be connected to the SV-AP-PANEL? and Do I need to multiplex the wires (bacause while Servos' wires connected to the SV-NET, they are also connected to the SV-AP-PANEL)?
I am glad if you can help me on this issue.

Thanks.

 

[jakej]

1 = no
2 = Trim motors are just that - they are usually low current draw motors & drive TRIM tabs. The SERVO motors are much more powerful & are powered directly from the electrical bus & controlled by the Dynon system via the SV network.
3 = correct.
4 = correct. Basically the a/pilot servos have power to the electrical bus as above & the grounds can be to a local airframe ground or remote ground bus if this is not an aluminium airframe.
The 4 servo network wires have to join to the SV network NONE of the servo wires connect to the a/pilot panel. The A/Panel ‘controls’ the servos via the network.
HTH

 

[AlpDmr]

Dear @jakej thanks for your answer. After checking your reply, I realized that maybe I could not fully explain the situation.

This aircraft is a GyroCopter, so there is no trim tab, it tries to operate the trimming functioanality with rotating (in pitch and roll axes) the rotor angles. So we assumed that this can be done by SERVOs.

1 - What is the wrong part? Using the SERVOs as trim motors? Because third drawing confirms what i said. What am i missing?
2 - Based on my last explanation, still do we need to add Pitch Trim Motor and Roll Trim Motors moreover like you explain in 2 ? Or can we use Pitch SERVO and Roll SERVO for this operation?

If using the SERVOs as trim motors is possible, how I can wire the SERVOs? I mean, if using SERVO Motors as Pitch Trim Motor and Roll Trim Motor is possible, how I can operate this functionality?

Thanks..

 

[Rhino]

Technically they're both servos because they provide feedback during operation. But in the aviation world, trim devices are usually referred to as motors, and autopilot devices as servos. As Jake pointed out though, autopilot servos are typically more powerful, and have a wider range of travel. Which one you need isn't an easy answer. It depends on your aircraft, the force needed to make the desired changes, and the range of motion needed. Being completely unfamiliar with gyrocopters, I won't attempt to answer that. How you wire them may depend on what you end up using.

 

[maartenversteeg]

You are exploring undiscovered territory, this is not what the trim / auto pilot system was build for.
As described trim and servo motors are something completely different:: Trim motors reduce the forces that are needed to perform any control action, either by the pilot or by the AP servo's. I you had an airplane that was always sufficiently in trim then you wouldn't need trim servo's to adjust for changing environment and balances. If your gyrocopter is balanced in that for neutral flight it doesn't need any rim , then you could try to control the gyro-copter using the Auto Pilot and the servo's, but always the Servo's are controlled by the auto pilot, not by the trims on the control stick

 

[Stevec]

You need to think of your setup as two completely different systems. First you have the AP servos that are controlled through the EFIS system and receive their control through the network hub, your second diagram. Next there is a trim system that uses external trim motors e.g. Ray Allen trim motors. The trim motors use a second physical link to the control system not to the servo motors. The autopilot system uses the optional remote head controller , diagram one and three, for easier access to AP functions but also contains a trim controller for two axis. This trim controller is separate from the autopilot when the autopilot is not engaged but when the autopilot is engaged the autopilot can apply trim corrections as needed through the trim motors. Remember for each axis you will have two methods of control an autopilot servo and a seperate trim motor both connected to the flight controls.

 

[AlpDmr]

Thank you ALL.
Actually, I am not an Avionics expert but I think I am being expertised slowly. I get it the idea (probably it is all about the differences of controlling the elevator and trim tab in airplane). And probably, Dynon mainly focused this kind of control mechanism (airplane flight controlling with elevator and trim tab).
So, "Houston, we have a problem".
Because of our control mechanism is a bit different adapting this system to dynon will be tough.
Final question (lets say we'll use SERVOs as trim motors at the same time), is it possible to (probably no) operate the servo motors from A/P panel by using mentioned way in diagram below?
If it is possible, may we have face with "current feedback" problem between AP/Panel and SV-NET-HUB?

 

[Stevec]

No

 

[Rhino]

If you're asking if it's possible to use autopilot servos for trim, yes, I believe it should be possible. Whether or not it's a good idea, or how well it might work, I have no idea.

As for your question about current, no, it won't feed back. Servo control commands go through the NET-HUB, but servo power does not. The servos are powered by a different path, so current on the power lines is not tied to the control lines from the hub.

 

[AlpDmr]

@jakej @Rhino @maartenversteeg @Stevec , Thank you all for your replys and efforts.

 

[jessesaint]

You cannot have auto pilot without the auto pilot servos. The trim functionality of the AP Panel is to trim a tab (sounds like this doesn't apply to you) to reduce the force being applied by the servo. The servo controls the actual flight surfaces by connecting to a cable or bell-crank. Just getting trim servos/motors won't give you auto pilot. If you have trim motors and want to control them, then you just need a relay deck or a DPDT (on)-off-(on) switch for each to adjust the trim tabs. This would not give you auto pilot functionality. If you are using auto pilot servos and don't have trim tabs, then you won't do anything with the 15-pin connector on the AP Panel. It will just be empty. You will connect the AP Panel to the 5-port hub or any other SV-Network connector to connect it to the system. 4 of the wires from each auto pilot servo will connect the same way, and then the power and ground connect to the bus and the CWS/Auto-Pilot-Disconnect wire (yellow) connects to a switch that gives momentary connection to ground when pressed.

 

[AlpDmr]

@jessesaint and everyone as well,
Thanks for your informative message. Let me change my question to explain our situation more clear.
Suppose we have an aircraft that hasn't trim tabs but only has ailerons and elevators. So while AutoPilot functionality uses these flight control surfaces and we haven't trim tabs, how we can operate trim functionality?
I mean, not all aircrafts have trim tabs and Garmin was capable to operate ailerons and elevators as trim functionality. Is there any option like that in Dynon as well?
Thanks right now.

 

[lancair360]

No trim tabs, no trim. Dynon doesn't have the capability to reset the "neutral" position of a flight control to trim it.

 

[Marc_J._Zeitlin]

Suppose we have an aircraft that hasn't trim tabs but only has ailerons and elevators...

How do you trim the plane manually? Trim tabs are hardly the only way to trim a plane. There are trim springs, movement of the whole elevator, and probably others. So whatever you do to trim the plane manually can be done electrically with an actuator, and the Dynon A/P head can control that trim system, if you want autotrim.