GSA28 questions

[Lyndon]

I have a Yaw, Roll and Pitch servo in my Kitfox S7. The Roll and Pitch servos can be hooked up to electric trim if your aircraft has it, mine only has a trim on the Pitch. 

It's wired through 11,12,13,14 on the servo and runs through an expensive electrical box, then to the electric trim motor on the horizontal stabiliser. So it can command the trim motor as it requires, I'm guessing to save on load on the GSA28. With the auto pilot on or off I believe I can still manually trim via the stick through the eclectic trim.

 

Finally my question. This is an option so do I need it. It's about $600 bucks. 

Thanks Lyndon 

[BurnieM]

A lot of people only have manual trim.

Not sure of the reasoning as I have never installed a GSA28 servo.

 

Interesting you went with a Yaw servo as this is often left out (cost?)

 

There is a FaceBook page for GFC500 (https://www.facebook.com/groups/833963897818892) that can probably answer your questions.

 

A power switch to quickly cut power to all servos and the GMC507 is a good idea.

 

 

Edited November 16 by BurnieM

[KRviator]

Sounds like the Dynon equivalent of Auto-Trim.  After several hundred hours behind and with the Dynon autopilot in the RV, no, I don't need auto-trim, the SkyView system will audibly announce Trim Down or Trim Up if the servo load is too much for too long, but if I had the autotrim module, it'd do it itself. The new toy will be getting the autotrim module though, but only in pitch.

[Lyndon]

Now that makes sense. I believe the G3X does the same thing and you feed some trim in manually.

I will get it, as It also solves the relay issues with both sticks using the trim motor. 

Thanks Lyndon 

 

[facthunter]

Why have auto trim? It's Just something else that could kill you. Nev

[Lyndon]

I'm sure it's the least of my issues 

 

Lyndon 

[facthunter]

Then you don't know what you don't know, to dismiss it so casually. . Nev

[KRviator]

4 minutes ago, facthunter said:

Why have auto trim? It's Just something else that could kill you. Nev

Why not have it? Even a grossly out-of-trim RV is easily controllable.

[Lyndon]

25 minutes ago, facthunter said:

Then you don't know what you don't know, to dismiss it so casually. . Nev

It was a flippent joke 🤣 

Edited November 17 by Lyndon

[Lyndon]

Anyway I look at it in another light. It's a safety item that may save my life.

Lyndon 

[facthunter]

You make a flippant joke about safety Matters do you? This is an Open Forum where many People visit, Act responsibly. How much actual experience and knowledge do you have of Autopilots. While they can save you (in a position you should not be in in the first place,( maybe) they can also Kill You.  I particularly question the use of auto trim. Why do you think you NEED it?  Nev

[BurnieM]

Good Garmin autopilot overview video;

https://www.youtube.com/watch?v=nQMWC5Aq1JM

 

This is an early video.

References to the G5 equally apply to G5, GI275, G3X Touch or G500 TXi.

 

There are a lot of confusing videos on the Garmin autopilot. The GMC507 is the autopilot mode controller.

The autopilot and flight director software runs on the G5, GI275, G3X Touch or G500 TXi.

If you have a G3X Touch you can run the autopilot without the GMC507 mode controller.

 

[KRviator]

On 17/11/2025 at 1:44 PM, facthunter said:

I particularly question the use of auto trim. Why do you think you NEED it?  Nev

No one needs auto-trim, unless you're an Airbus driver, but it's nice to have. No one needs an autopilot, or megadollar EFIS, but again, they're very nice to have. I'll have a 3-screen EFIS in the new project instead of a 6-pack and round gauges. I don't need it, but I certainly want it because it'll lower my workload considerably.

[facthunter]

It's a RISK. Funny you mention Airbus because an A300 in the US overrun the runway on take off because the trim had gone full nose down. Also the Para drop Porter fatality recently. Autopilots (all of them)  have  UNSAFE MODES and are a trap for the unwary. IF  YOU are NOT properly trained by someone who themselves KNOW. It'd dead easy to take the Pole occasionally and  check how far out of trim the Plane is. Good airmanship. There should also be some way to QUICKLY stop the trim.  Big stuff has a trim BRAKE and it's really sudden. What's wrong with Manual trim? You need constant practice to use it correctly and It's little Physical effort in the stuff we fly. Nev

 

[BrendAn]

3 hours ago, KRviator said:

No one needs auto-trim, unless you're an Airbus driver, but it's nice to have. No one needs an autopilot, or megadollar EFIS, but again, they're very nice to have. I'll have a 3-screen EFIS in the new project instead of a 6-pack and round gauges. I don't need it, but I certainly want it because it'll lower my workload considerably.

What's the new project , sounds interesting 

[KRviator]

1 hour ago, facthunter said:

It's a RISK. Funny you mention Airbus because an A300 in the US overrun the runway on take off because the trim had gone full nose down. Also the Para drop Porter fatality recently. Autopilots (all of them)  have  UNSAFE MODES and are a trap for the unwary. IF  YOU are NOT properly trained by someone who themselves KNOW. It'd dead easy to take the Pole occasionally and  check how far out of trim the Plane is. Good airmanship. There should also be some way to QUICKLY stop the trim.  Big stuff has a trim BRAKE and it's really sudden. What's wrong with Manual trim? You need constant practice to use it correctly and It's little Physical effort in the stuff we fly. Nev

 

And an A320 was very nearly lost after the Captains sidestick was miswired during recent avionics work - but does that mean we should do away with FBW? 'Course not.

We fly single-engine aircraft, sometimes over unforgiving terrain. Everything in aviation (and life) has risk associated with it, but just because there is a risk of something happening, does not mean it is probable, or even likely and so we should not undertake that activity (or install that auto-trim module). You seem to be assuming that there is no way to stop the trim during an inadvertent auto-trim movement, I don't know if that's because you're unfamiliar with the Garmin or Dynon systems, or autotrim in general, but pressing the AP Disconnect button will disengage autotrim, as will, IIRC, trimming opposite the direction the trim is running.

As for what's wrong with manual trim? There's nothing inherently wrong with it, but electric trim is much nicer to have under your thumb rather than twisting a knob while I'd prefer to have my hand holding the throttle full forward (in the case of the RV), it is often lighter and able to be interfaced with the autopilot. For smaller aircraft like my old KR2, the little manual lever on the longeron that connected to a bit of wire-in-tube to the trim tab was more than adequate. But as things get bigger, technology takes precedence.

Case in point...I'm installing EFI instead of the old RSA-5 system, but a risk assessment shows that I need to ensure continuity of electrons, so that requires a backup alternator. Should I stay with the old 1960's era injection system just because it doesn't require power? Heck no. EFI is well (flight) proven now, enables instant car-like starts - hot or cold, it allows LOP, I can run 98 Mogas, and I'll have the ability to trim fuel to each cylinder individually to balance the EGT's and the system has an option that provides a backup computer and fuel pump should the primary fail.

The benefits outweigh the negatives and any risk can be mitigated. Same for autopilot, autotrim, or any other modern gadget in our aircraft.

[skippydiesel]

"The benefits outweigh the negatives and any risk can be mitigated. "

 

When you start to talk about fitting such gadgets as auto/electric trim, autopilot, to light aircraft ( 600kg MTO? ) navigation/landing lights to VFR only aircraft, etc. I think it fair to say that for the most part thats exactly what they are, gadgets/bling - they do little if anything to enhance the aircrafts flying characteristics or the skill of the pilot and may increase risk.

 

So the "benefits " are really in the aspiration (mind) of the pilot/builder. The increased risk & cost, is overshadowed by the want, as there is clearly little, to no need.

 

Who am I to stand in the way of their enjoyment/aspirations. All I ask - please do not fly your "enhanced" aircraft over my house 🥺.

 

😈

[facthunter]

Safe AFFORDABLE flying where you learn to fly mainly by looking outside the aircraft visually in contact with the real world. Lots of gadgets, and a Fancy watch do not a Good Pilot make.  Nev