EFIS has a new trick

It got to be a little too late last night by the time I could write a blog post that it was bed time. So here is what we did yesterday.


I was able to get the rest of the fuel and oil hoses fire sleeved. Now everything that carries a flammable liquid is protected. Don’t mind the mess, I have to start tidying things up and securing hoses and wires. Murphy’s Law… If I start securing now, I will figure out a reason I have to pull the engine off… May as well be optimistic soon though.



Brown Santa (UPS Guy) came yesterday and delivered more fittings as well. This meant I could finally finish plumbing for the manifold pressure system. This comes from the induction elbow to a 4 way split where it then goes to the gauge transducer and each P-Mag. The silicone hose is a tight fit on the barb fittings off of the 4 way fitting. It certainly won’t pull off, I just hope it isn’t enough stress to crack the hose. It is a non-event if the hose does break. The ignitions then work as traditional mags and the manifold pressure indication is lost. Neither thing being mission critical. For now I am just planning on keeping an eye on it and seeing how it ages.


Lastly, I was able to get the bleed air system plumbed. I know, most people are probably saying what is a bleed air system and why is it necessary. The short answer is it isn’t yet, though doesn’t hurt either. What it does is give an induction air pressure reference to the injectors. Turbocharged airplanes often require this since the induction air pressure is much different than the ambient pressure in the cowl. James Redmon has this system installed in his airplane because he is running cRAM air. I plan on eventually experimenting with different induction setups, so this may become necessary in the future. Airflow performance also recommends it for anyone operating in a dusty/dirty environment as it keeps all air going to the fuel injectors filtered.


As far as I can tell that should complete all of the plumbing in the engine compartment. Onward.

The other task that I did was make up the nut plate washers that get bonded onto the F22 bulkhead for canard attachment. There is no convenient way of getting at the bolt and nut single handedly, so this is what the plans uses so that removing the canard can be a solo activity. I have to bond them in yet, and didn’t yesterday since Eric was here and we were working on wiring.


Eric got the ELT wired up, we can check that one off the list. Boy am I glad that I have an experienced steady hand at soldiering here to help. This DIN connector that the ELT uses is tiny. To land all the wires on it in the proper locations with strong soldier joints is important and actually had to be disassembled and reassembled once to correct a jumper. Can’t thank Eric enough.


Lastly, Eric worked on the discrete inputs to the Garmin G3X. These are a canopy unlatched sensor and a landing gear position sensor. We are still working out the details on the canopy switch installation, but the landing gear comes with a switch already installed, all we had to do was run two wires.

Now the EFIS knows if the gear is down or not. The EFIS gives 3 high/low warning tones through the pilot’s headset and also flashes a red “Check Gear” under the altimeter if the landing gear is not down and other conditions are met. Basically those conditions mean that you are in the landing phase of flight. The other conditions can be if the airspeed is below a certain value, altitude below a certain value, etc. I will have to check to see how they are currently set and evaluate if I need any changes. But for right now, it is working, see for yourself.

Update: I forgot, Eric also got the pitch trim position sensor wired up. We need to rig it to the pitch trim yet, but the sensor works.

2 thoughts on “EFIS has a new trick

  1. I worked with Garmin to develop the “Speed Brake” and “Canopy” warning logic for the discreets. So, you should be able to select those items in the menu.

    There is logic behind each to limit false alerts…like the gear warning.

    1. Outstanding! I will look more into the software side of that. Do you need a separate discrete input for the speed brake for the warning? Or will my position potentiometer drive the warning as well?

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