TruTrack autopilot

[seastar]

Do any of you have a TruTrack autopilot installed in your Carbon Cub?
I have a TruTrack Digiflight IIVS installed and am interested in sharing experiences.
Bill

[turbopilot]

Do any of you have a TruTrack autopilot installed in your Carbon Cub?
I have a TruTrack Digiflight IIVS installed and am interested in sharing experiences.
Bill

I have been thinking about it. How does it work?

[seastar]

Randy
Thanks for the report on the #3 TruTrack installation.
I am sure mine will work as well with the new controller.

Question ---Why do you recomend such a high minimun airspeed?
85 mph seems very close to normal cruse and does not allow much room for climbs with the autopilot on.
Normal long range cruse settings (low power) at altitude may well be below 85 mph indicated making the autopilot unusable when needed most.
I would think that at least as low as Vy would be better or maybe Vx?
Is there some aircraft aerodynamic reason or some problem with the autopilot response at low airspeeds?
Just trying to get an engineering sense of the reasons for your recomending 85 mph.
125 mph sounds good for Vmax.
I am going to install my new controller today and hope to get in a test flight.
I'll let you know how it works.
Bill

[randylervold]

Randy
Question ---Why do you recomend such a high minimun airspeed?
85 mph seems very close to normal cruse and does not allow much room for climbs with the autopilot on.
Normal long range cruse settings (low power) at altitude may well be below 85 mph indicated making the autopilot unusable when needed most.
I would think that at least as low as Vy would be better or maybe Vx?
Is there some aircraft aerodynamic reason or some problem with the autopilot response at low airspeeds?
Just trying to get an engineering sense of the reasons for your recomending 85 mph.
125 mph sounds good for Vmax.
I am going to install my new controller today and hope to get in a test flight.
I'll let you know how it works.
Bill

My 85 mph LOW AS recommendation has no engineering basis, just trying to make the autopilot's assignment achievable. When the airplane gets slow it is harder for the AP to fly it, not as much response available due to the low AS, and it takes longer for corrections which the software might struggle with. I'm sure it could fly it at 75 mph no problem in smooth air, in turbulence however it might be a bit of a challenge. It's easy to change the setting so go up and try it at various slower speeds in 5 mph increments and let us know how it does.
My approach is to start with a speed envelope that we know the AP can handle, then incrementally expand it so we arrive at a reasonable range that works.

[Pete D]

Bill,

Glad to hear its all working properly!

Pete D.

[randylervold]

Bill, glad it hear it is all now worked out, enjoy!

[randylervold]

Andrew Barker, General Manager at TruTrak, was in town yesterday just as we were about to test fly autopilot install #3 so I took him along and also learned what the problem has been all along. Just to close the loop on the issue I thought readers might find it interesting.

The story begins when we sent a customer's Sport Cub S2 back to TruTrak last fall to have the installation engineered. That includes the servo mounts and whatever software settings are necessary for proper AP performance with this airframe. TruTrak did the work and reported that it flew perfectly. In fact Jim Younkin, legendary autopilot guru and company owner, called me after they finished to tell me how much he liked the plane, and of course that the AP worked perfectly. Turns out TruTrak has made all the necessary parameter adjustments in the hardware. Once they had the settings they intended to shift all this to software. Problem is the software was not saving the settings and it took two tries to get that problem fixed. Kudos to our Texas dealer, Scot Warren, for discovering this and assisting in the process.

Andrew and I tested the AP in both turbulent air down low, then climbed up and found some smooth air. We flew it down to 70 mph IAS and he made two more small software adjustments in flight. Once we landed he recorded the changes and we now have a standardized set of parameters and software that remembers them once they are recorded. My understanding is that the head unit is loaded with them when ordered from TruTrak, but they can be set in the field also if needed.

So, I think we can consider this issue resolved, and thanks to everyone involved for their assistance in working it out: Bill Rice, John Duncan, Scot Warren, and the TruTrak and CubCrafter's crews. Mr. Rice and Mr. Duncan, perhaps you can comment how they are working for you as aircraft owners.

[Pete D]

Ok, I have the settings recommended for the autopilot installation in the Carbon Cub from Tru Trak. If you look in the paperwork that came with your plane you should have a copy of the installation manual for the autopilot, if not you can access it here;

http://www.trutrakflightsystems.com/...talManual1.pdf (click or copy/paste)

Starting on page three it shows how to step by step enter setup mode and adjust the parameters. It has screen shots for each value showing generic numbers. You want to use the numbers below instead of the ones shown in the manual.

Some of these numbers may or may not be the same as what you have set already.

Lat Activity = 5
Lat Torque = 12
Baud = 4800
Bank Angle = Med
Microactivity = 0
GPSS Gain = 16
YD = N

Vrt Activity = 5
Vrt Torque = 12
Min AS = 70
Max AS = 120
Static Lag = 0
Microactivity = 0
Half step = N

Pete D

[Pete D]

I don't have the settings available right now, Tru Trak is supposed to get those to me and when they do we can get those to the people that already have auto pilots in their Carbon Cubs. Future installs will come from Tru Trak pre-programed with the settings and will be checked on installation here.

Pete

[seastar]

Turbo
So far, not very well but TruTrack is working on it.
I hope to hear more tomorrow.
I was hoping someone here had worked through the settings and could help me fix mine.
Bill