Hi Terry Im interested in rolling my own flap and trim control. Are
you willing to share your setup and code design.

Steve Izett



Steve, what board are you planning to use? I have a program that I
wrote for an Arduino Mega that reads a POT connected to the flap
actuator and activates an H bridge. It works- press the down button
and get 10 degrees, press it again get 20 and the third time get max,
which on my plane is 40. Press it once and it goes up a notch, etc. I
have tried to put it on an Uno or Tiny and it doesn't work just
right, but on the Mega 2560 it works fine.

I re-purposed a pair of Microsoft joysticks for my sticks- the center
joystick is elevator and aileron trim, the buttons on the left are up
and down flaps, and the buttons on the right are interior lighting.
The thumb button is autopilot off and on. The trigger is PTT. Works
great.

If anybody wants more info, shout at me.

Let me know if this will work for you-

Kevin Alderman


Hi Kevin
Thanks for the feedback. I’m using the Colour Maximite which used interpreted basic script.
Your flap control is similar to what I plan to do. A few lines of code with a pot as feedback.
I’m interested in automating the pitch trim and wondering whether air speed, flap position and weight and balance
will be consistent data to reliably adjust trim, or will it require feedback from the autopilot system?
If it requires data from the skyview bus then that puts it beyond my time/ability/risk decision matrix.

Cheers

Steve Izett

https://www.kickstarter.com/projects/818225433/maximite-bbx-the-modern-day-basic-language-compute <https://www.kickstarter.com/projects/818225433/maximite-bbx-the-modern-day-basic-language-compute>

Wow!
That is really cool Steve.
I got to get one and try it out.

Looks like I can port my GPS driven Moving Map software
I wrote in 1990.

Finally one can write real time software on this jewel.

Paul Lamar

Not sure I would try to couple trim to the A/P. The A/P is always making minute adjustments as it flies, and to add another variable to the system such as an automatically adjusting pitch trim might cause an oscillation issue. Also, I can see the system being able to adjust for burned fuel if you have a totalizer, but any other adjustments would require in depth programming.

I plan to measure the pressure i.e output at the pitot static lines connected to a pressure sensor so I can equate the pressure to airspeed. I can also connect a pressure system to an airspeed indicator at my desk as well- might be safer. I will then use this to correlate the flap deployment speeds into the program so that you can only get 10 deg of flaps > 110, 20 at > 100, and 40 at > 80. I also have incorporated a sort of failsafe to raise the flaps at any indication of full throttle- like a missed approach. The flaps will retract at first quickly from 40 to 20, then slowly to 0 as airspeed increases. In low visibility conditions like an IFR approach the flaps would be one less thing to worry about.

Kevin Alderman


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