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Dynon Heated Pitot ground

RVG8tor

Well Known Member
I am starting to wire things and wondered if a local ground to a wing rib is fine for the pitot or should I run a separate ground wire, what say you all? I have the Dynon heated AOA/Pitot.

I wonder if the controller acts as a ground, I still need to ask Dynon. But I hooked everything up to test and that went well, then I hooked up things to simulate an airframe ground, the power source ground to the wing and the positive to the controller wire (red), and I had not hooked up the controller ground wire to the wing rib, but the pitot heat kicked on, hmmm. some how it was getting a ground, the only thing I could think of was the controller being attached to the wing rib was making a ground, this might be good or bad, I will have to ask Dynon.

Thanks for any help, I did no find anything on topic with a quick search of "pitot ground"
 
hmmm, interesting. I am at the same stage with my -10 and plan a local ground on the rib.

"Nemo" - are you lost? ;)
 
Dynon Answer

I posted on Dynon forum that I was getting a ground with the power source grounded to the airframe but the black ground wire from the controller not connected and this is what Dynon support said:


The controller box is grounded to the circuit internally, so if it's hooked to a metal airplane, it will operate.

It wasn't designed to use just this ground, so while it won't hurt anything in the short term, you do need to hook the ground wire up as well, even if it is just to local grounding spot.



So that answers part of the puzzle, now will an airframe ground for the pitot cause any static noise issues?
 
No Noise with Local Ground

I have a heated pitot grounded to the wing rib with the same fastener that is holding the controller box. No noise with the pitot turned on in the headset. I use a Clarity Aloft and I can hear anything that has static.
 
Just installed mine a couple hours ago...

Talk about timing. I just did mine this evening, I ran a set of nutplates on the backside of the same rib where I'm mounting the pitot mast, and attached the controller to those nutplates, with local grounding on one of the screws. To be fair, I have not tested it yet, I'll let you know tomorrow if I get good grounding. The Dynon install docs say local ground is fine. And yes, I did remove enough primer under the nutplates to get a good electrical contact. With the controller this close to the pitot, and leaving a service loop of plastic tubing for the pressure lines, you can remove the pitot from the mast at any time by disconnecting the wires and tubing externally after pulling them through the mast.

1002001.jpg
 
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To ground locally or not to? That is the question...

An old thread from 2009...

I was just reviewing the Dynon Heated Pitot Installation guide and ran across this information:

Heated_Unheated_AOA_Pitoti_Probe_Installation_Guide_Rev_D.pdf
Dated May 2016, Page 3-2

"Do not connect the Black (Ground) wire to the airframe as a Ground connection. Doing so will introduce high currents (10A) into the airframe. This can introduce a significant voltage drop, and potentially cause engine instrumentation, avionics, and audio system electrical problems."

Figure 7 on page 3-4 shows the Heater Controller Black (GND) wire as "To permanent connection to aircraft ground."

Table 3 on page 3-5 shows the Black Ground wire notes as "Constant connection to ground (not routed through a switch or fuse/circuit breaker)."

I was planning on just doing a Local Ground near the Heater Controller and not having to string another wire through the wing to get to my forest of ground tabs on the interior firewall. The comment about "high currents" through the airframe really has me confused. It's an aluminum airframe! It should certainly be able to take the ground load. I have only a few local grounds (baggage light, landing lights) which are low current LED's.

When I retrofitted Josh's RV-9A with a heated pitot, I did use a Local Ground connection and it worked just fine. I'm just wondering what Dynon's rationale is for this note about "high currents" causing potential problems with a Local Ground.
 
Last edited by a moderator:
An old thread from 2009...

I was just reviewing the Dynon Heated Pitot Installation guide and ran across this information:

Heated_Unheated_AOA_Pitoti_Probe_Installation_Guide_Rev_D.pdf
Dated May 2016, Page 3-2

"Do not connect the Black (Ground) wire to the airframe as a Ground connection. Doing so will introduce high currents (10A) into the airframe. This can introduce a significant voltage drop, and potentially cause engine instrumentation, avionics, and audio system electrical problems."

Figure 7 on page 3-4 shows the Heater Controller Black (GND) wire as "To permanent connection to aircraft ground."

Table 3 on page 3-5 shows the Black Ground wire notes as "Constant connection to ground (not routed through a switch or fuse/circuit breaker)."

I was planning on just doing a Local Ground near the Heater Controller and not having to string another wire through the wing to get to my forest of ground tabs on the interior firewall. The comment about "high currents" through the airframe really has me confused. It's an aluminum airframe! It should certainly be able to take the ground load. I have only a few local grounds (baggage light, landing lights) which are low current LED's.

When I retrofitted Josh's RV-9A with a heated pitot, I did use a Local Ground connection and it worked just fine. I'm just wondering what Dynon's rationale is for this note about "high currents" causing potential problems with a Local Ground.

My background as an audio engineer, dictates that you avoid ground loops at all costs. All my grounds are home run back to the forest of tabs, including the pitot. I originally had a Gretz pitot. When it failed, I switched to a Dynon. I may had added a little weight, but I have a quiet intercom.
 
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I ran mine all the way back to the forest of tabs, easier now than having to troubleshoot radio noises later.
 
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