PDA

View Full Version : Question: Garmin anti-over center bracket


MS19087
08-12-2020, 10:52 AM
I'm installing Garmin servos in my RV-14. I am using Vans install kits, materials and instructions, etc. One question - the servos as supplied by Garmin include a bracket that I believe is to be used to prevent an over center situation. This bracket that gets sandwiched between servo shaft and arm. Vans instructions do not provide any information on the use of such bracket. I have not installed them and just followed Van's install instruction exactly. I assume we provide protection for an over center situation by following these instructions and measurements of associated push rods, end stops and rigging.

Any commentary greatly appreciated.

g3xpert
08-12-2020, 11:52 AM
All Garmin GSA28 (experimental) servos are shipped with the over-center bracket. This is intended to be used for its specific purpose in a wide range of experimental autopilot installs. With a well-engineered, kitted installation package (like we typically find on our newer RVs, or as provided by VANS), the use of the bracket may not be necessary.

For example, none of the certificated GFC500 Autopilot Kits have stop brackets included with the PMA model GSA28 servos, because the kits are highly engineered to guarantee no possibility of an over-center control situation and installation geometry/location specifics are strictly followed. In the experimental world that is not a guarantee, so the bracket is provided.

Use at your discretion, or by VANS recommendation.

BR,

Brad

MS19087
08-12-2020, 12:06 PM
All Garmin GSA28 (experimental) servos are shipped with the over-center bracket. This is intended to be used for its specific purpose in a wide range of experimental autopilot installs. With a well-engineered, kitted installation package (like we typically find on our newer RVs, or as provided by VANS), the use of the bracket may not be necessary.

For example, none of the certificated GFC500 Autopilot Kits have stop brackets included with the PMA model GSA28 servos, because the kits are highly engineered to guarantee no possibility of an over-center control situation and installation geometry/location specifics are strictly followed. In the experimental world that is not a guarantee, so the bracket is provided.

Use at your discretion, or by VANS recommendation.

BR,

Brad

That was pretty much my assumption - thanks for confirmation!!

N49ex
08-12-2020, 06:28 PM
This is just my opinion, but I would highly recommend using the bracket, if you have a geometry that could allow an over center travel one way or another. While Garmin seems to have stated it neutrally, likely to sidestep legal responsibility, I think it is not a simple matter of preference. Should such a travel occur, it is a formula for certain disaster as the resultant control lock up is likely not able to be overcome by hand.