Trim, flap, and fuel indicators AEM style

[WaiexB22]

I am running an AEM ECU for my engine. I am working with Bryan Dacus with BD turnkey out of Reno, NV to get this built, programmed, and tuned. There is a panel mounted display that provides my engine information including, RPM, oil temp, oil pressure, water temp, water pressure, EGT on each cylinder, fuel pressure, AFR info, and much more related directly to the engine. One of the cool things about this system is that it can accept a variety of configurable inputs through a can bus module. I am going to integrate the following inputs to the system for display on the panel:

1. Flap position - There is a resistive output from the sonex provided actuator that will integrate directly. (If anyone has taken readings on the actuator vs. flap position on the actuator provided with the TSB for the b-model I would be very interested)

2. Fuel level - I have the sonex resistance level probe. This will feed in just like the flap position. I have the resistance vs. fuel levels for the a-model, but can't seem to find the for the b-model. Can anyone point me to these.

3. Trim position indicator - This one is a little more fun. The linear travel on the dial-a-trim block is approximately 4.75 inches. I bought a 5 inch suspension travel sensor. It is a lightweight, robust, linear potentiometer that was recommended to me for this purpose. It is long, so my plan is to run a second cable from the dial-a-trim to the actuator, which I will remote mount. There is almost no resistance on the sensor, but I will need a really light spring to tension the cable.

I will document my efforts here and hopefully it will help someone else.

BD turnkey: https://bdturnkeyengines.com/yamaha-apex

The sensor I bought: https://thesensorconnection.com/product ... ter?v=3003

Below is a working layout of the primary display. You have another series of screens that give you basically anything you want to dig for related to the engine. You can see flap position (F) and trim position (T) on the right. Fuel level is the green bar at the bottom.

IMG_1298.PNG (101.75 KiB) Viewed 2141 times

The sensor next to the trim dial is below:

[WaiexB22]

I mounted the new flap actuator and guessed on the position of the torque tube vs. flap position to get some resistance readings programmed as a starting point. Due to my shop space, I am waiting to build my wings until I absolutely have to, which is coming soon. Once everything is together and I can measure the actual position I will get the resistance readings fine tuned.

For the trim position sensor I fabricated the mount below. The position sensor works great and I was able to collect the resistance vs. position readings from the sensor. It works smoothly and adds zero resistance to the trim dial. I lost maybe an 1/8 inch travel for the plate, but I don't think I will miss it. Anyone with an EFIS capable of accepting a variable resistance input should be able to use something like this if they wanted. It may not be a big deal to most and it may be totally unnecessary, but I hated the idea of not having a trim position indicator at takeoff and I didn't want to "count turns" every time.

For the fuel level, for now I used readings that sonex published long ago. Once I am ready to fill the tank completely I will add fuel 1 gallon at a time and take accurate resistance readings then. I also plan to mark the back side of the tank.

[Bryan Cotton]

Once I am ready to fill the tank completely I will add fuel 1 gallon at a time and take accurate resistance readings then. I also plan to mark the back side of the tank.

Looks good! We count turns but also have a small knob installed on the wheel.

I used a sawhorse and went back in forth between 3-point and level attitude when I calibrated my tank. We only have markings and a camera.
https://www.youtube.com/shorts/rAUjAJ73rN0

[Murray Parr]

We count turns but also have a small knob installed on the wheel.

Hi Bryan,

Your Dial a Trim seems to turn quite freely compared to mine but I might try to copy your idea. What did you use to make the Trim wheel rotator knob out of? Looks like it turns on a bearing or bushing?

[Bryan Cotton]

Hi Bryan,

Your Dial a Trim seems to turn quite freely compared to mine but I might try to copy your idea. What did you use to make the Trim wheel rotator knob out of? Looks like it turns on a bearing or bushing?

I made a phenolic knob for my wheel. I drilled and tapped the wheel for a #8 screw and that is the pivot. There is also a nut on the backside. So it is just the inside of the phenolic knob against the shaft of the screw. I think I socked it down until all the threads were in the wheel. Simple.

[WaiexB22]

Bryan - you win on simplicity and weight for the trim. I clearly don't need this based on the forces in your video. The knob was a great idea and makes counting turns a lot easier.

Regardless, I had fun making it, hopefully it will be nice to have, and it weighs around 9 ounces all in.