Does anyone know the diameter of the control sticks offhand; 3/4",7/8",1"?
I'm going to order my grips and this is the parameter they need
Mine (a Series 5) are 7/8".
Eric Page
Building: Kitfox 5 Safari | Rotax 912iS | Dynon HDX
Member: EAA Lifetime, AOPA, ALPA
ATP: AMEL | Comm: ASEL, Glider | ATCS: CTO
Map of Landings
Be aware that if you want to control trim with buttons on the grip you may need to
change the wiring a bit since those buttons typically can't handle the current needed
to drive the trim servo motor. Also note that the trim motor direction is determined
by the input voltage polarity so operation with 2 switches requires some additional
circuitry. It's also more difficult to have both the Kitfox-supplied switch and grip buttons
at the same time.
If you need more details on how to wire it up just let me know here and I'll post
the info on my setup which uses the Ray-Allen grips, Garmin autopilot servos and the
TCW Safety Trim Booster.
Victor
Building SS7
915iS
Garmin G3x
Hey Victor,
If you could post that here that would be awesome! I do plan to use the TCW Safety Trim Booster for the very reason you mentioned.
I'll also be running a Vertical Power VPX; as I understand things so far, the VPX is able to accept trim inputs from both pilot/copilot without the need for an external relay, but it makes no distinction between the two. Alternatively, I can also add the Garmin GAD-27 (in addition to VPX) which also accepts two trim inputs, but has separate inputs for pilot/copilot, which allows pilot controls to override the copilot....neat feature, but there's so much overlapping functionality between GAD/VPX, that I'm not sure it's worth the added expense. Anyhow, back to your point, I would love any help you're willing to give!
The parts I used are:
Ray Allen G405 Stick Grip: https://www.aircraftspruce.com/catal...clickkey=41355
Ray Allen REL-1 Servo Relay Deck: https://www.aircraftspruce.com/catal...lickkey=852685
Garmin GSA-28 Servo: https://www.aircraftspruce.com/catal...h_11-11450.php
TCW Safety Trim Booster: https://www.aircraftspruce.com/catal...clickkey=17761
Kitfox-supplied Pitch Trim Servo
Note that the Pitch Servo (Garmin) and Pitch Trim Servo (Kitfox-supplied) are 2 different devices. This design only applies the devices listed above.
The system is based on the G3x Autopilot. The key problem that has to be solved is to convert the stick grip button signal (depressed=signal to ground)
to the reverse polarity signal needed by the pitch trim servo.
The key points that drive the design are:
1) In the Ray Allen grip when a button is depressed it connects the signal to ground.
2) The Ray Allen grip buttons can only handle 1 amp and the pitch trim servo draws 2.5 amps which is
why the servo booster is needed.
3) The pitch servo has trim outputs so that the autopilot can control the trim as well.
4) The trim outputs from the Ray Allen servo deck are combined with the autopilot trim commands
in the Garmin pitch servo.
5) The combined pitch servo trim outputs are then fed into the TCW Safety Trim Booster to create the signal to
drive the pitch trim servo.
The simplified diagram is:
Screen Shot 2024-04-30 at 10.26.41 AM.jpg
I skipped trying to figure out how to use the Kitfox-supplied trim switch along with the stick grip switches because
it seemed too complicated to implement.
If you're not using the Garmin Autopilot/Servos you can connect the output of the servo relay deck directly to the
TCW Safety Trim Booster.
The installation instructions for the 4 devices provide enough info to create the wiring diagram. I don't have one
that I can attach unfortunately. If you need more detailed help let me know and I'd be happy to help out. Since
I have not flown my KF yet I don't know for sure if everything is correct but the trim up/down buttons on the
stick grips are working as expected.
Victor
Building SS7
915iS
Garmin G3x