SV-ap-panel trim controller

[bobl_51]

Is there any issue with using the 2nd trim controller circuit to control my flap motor? My flap switch is on the stick, and using the ap-panel trim controller makes the switch wiring slightly simpler and allows a co-pilot to also to have flap control.

The only thing I can think of is the 5 second "stuck switch" timeout - it takes longer than that to fully retract/extend the flaps.

 

[vlittle]

Trim motors only require about 500 mA max current, whereas flaps need up to 10 amps, so this is beyond the capabilities of the circuit.

However, you could use the trim circuit to drive a pair of flap automotive relays if you really wanted to.
The details depend on how Dynon implements the trim drive.... They could drive the relays directly or you may need a couple of steering diodes.

It's a clever idea to reuse this circuit... Gives you both pilot and copilot control plus the buttons on the controller. I hope the speed scheduling can be selectively turned off for the flaps channel.

Vern

 

[mrdaud]

If indeed there is some utility in using the the trim circuit for flap control, and as Vern has said, you can't drive the flap motor directly off the trim circuit. However, I would avoid anything related to automotive in regard to electronics. Take a look at www.aircraftextras.com. They have a nice 10 amp flap relay board for $29. I am actually using this on my plane along with the flap safety switch and FPS flap positioning system. Note, if you choose to go that route and you have a non-clutch controlled flap motor, you will need to ask for the relay block with reversed diodes. Read the installation instructions for the non-clutch driven motor carefully before you order the relay board. Or you can reverse the diodes yourself if you are handy at soldering.

 

[vlittle]

If indeed there is some utility in using the the trim circuit for flap control, and as Vern has said, you can't drive the flap motor directly off the trim circuit.  However, I would avoid anything related to automotive in regard to electronics....   

My history in automotive electronics design begs to differ.... This vehicle was the first 3-phase AC induction drive electric car. Engineers from this project went on to GM to develop electric vehicles. I designed a version of the drive controller using microprocessors and high power 'hockey puck' thyristors switching hundreds of amps and hundreds of volts.

Vern

 

[DBRV10]

Folks,

There is coming soon the auto trim software which will control the trim in roll and pitch. If you used relays to drive off the trim outputs, that would make for really weird flap extensions when the software wanted to retrim when the AP is engaged

Operate flaps with either a VPX or a conventional circuit. There is nothing to be gained from the trim controller.

 

[dynonsupport]

David,
The auto trim can be easily configured to know pitch is on one of the "trim" axis of the AP module, but that something else is on the other axis. So that is not an issue. It is also possible to completely disable any speed scheduling on a specific axis.

And we're with Vern on using automotive parts. I'd much rather be in a plane with the reliability of any modern, large volume car manufacturer than the reliability of any GA aircraft. The QA process every part in a car receives today is amazing, and the costs are incredibly low for the complexity.

 

[DBRV10]

OK…..

 

[vlittle]

David,
The auto trim can be easily configured to know pitch is on one of the "trim" axis of the AP module, but that something else is on the other axis. So that is not an issue. It is also possible to completely disable any speed scheduling on a specific axis.

And we're with Vern on using automotive parts. I'd much rather be in a plane with the reliability of any modern, large volume car manufacturer than the reliability of any GA aircraft. The QA process every part in a car receives today is amazing, and the costs are incredibly low for the complexity.

Autotrim, huh? Nice to see you catching up .  The following link shows how to use the automotive relays configured to drive flaps.... And my autotrim controller that's been flying for many months.

http://www.vx-aviation.com/sprocket/photos/panel_elec/schematics/TRIM.pdf

Vern

 

[mmarien]

I use automotive relays for quite a few of the functions in my Glasair. The VP-X is limited to 10A for the flaps whereas the Glasair flap motor calls for a 15A breaker. The FPS which I initially installed is also limited to 10A. The relays I installed to solve the problem have been running my flaps for about 4 years.

My essential or emergency bus to drive my electronic fuel injection and ignition is also switched with standard Bosch automotive relays.

 

[jakej]

Murray
FYI - The VP-X flap circuit has been improved to cater for the higher current draw of the Glasair & Lancair flap motors.  I have no issues using the VP-X for the flaps 
No need for relays etc.

Jake J

 

[gtae07]

And we're with Vern on using automotive parts. I'd much rather be in a plane with the reliability of any modern, large volume car manufacturer than the reliability of any GA aircraft. The QA process every part in a car receives today is amazing, and the costs are incredibly low for the complexity.

Automotive manufacturers do have the advantage of very high volumes and more automated production methods. However, they achieve that quality and reliability without DOT/regulatory involvement and approval of every step of every process of every part. Something to think about :-?

 

[mmarien]

FYI - The VP-X flap circuit has been improved to cater for the higher current draw of the Glasair & Lancair flap motors.  I have no issues using the VP-X for the flaps  Smiley
No need for relays etc.

Thanks for the info Jake. I'll probably leave it for now but certainly consider eliminating the relays if I have to do any changes there.