During EAA/OSH 2024 I was searching for an ignition system upgrade for my B55 Baron. I had heard about some of the improvements that several manufacturers had made in improving upon the ubiquitous magneto, which has served piston GA engines well for over half a century.

I was most impressed with the Electroair STC'd system because, well, just look at the monster ignition coil it employs in creating fire across the spark plug gap. It's the size of a large brick and a bit heavier with ancestry from automotive high energy ignition systems!

Electroair Ignition Coil

The other so-called electronic ignition systems utilize a simpler and much smaller package that was about the same size footprint as a conventional magneto, essentially creating an electronic magneto. Whereas, I believe the Electroair system represents a TRUE electronic ignition with it's monster coil creating 70,000 volts and a duration of about 20° of crank rotation vs. ~12,000 volts and 5° respectively for a conventional magneto, a controller that advances ignition timing with altitude, a replacement cockpit control panel that eliminates the old rotary magneto start switches and reported gains in fuel efficiency and horsepower.

Electroair Switch Control Panel

Make no mistake, this install is very extensive and labor intensive on a Baron (much less so on a Bonanza), due to the coil mounting locations being limited to the nacelle cavities and the fact that you are installing TWO systems! For economics, I highly recommend owner assisting in all the tedious wire pulling and fabrication grunt work (as I did under IA supervision for my install) as the way to get the lowest cost install as well as tidy and precise workmanship that will satisfy you.

By no means is this narrative to be considered as the ONLY way to install an Electroair ignition system in a 55-Series Baron, it is however, the way that my IA and me chose to install it in accordance with the Electroair Install Manual and published FAA repair and maintenance practices in AC 43.13.

The STC'd kit is packaged extremely well and nested in styrofoam compartments with a flash drive containing all the install and STC documentation.

Electroair Ignition Reported Benefits

Once I committed to the Electroair system my IA and I began the head scratching on how we would approach the install of the components and wiring in a B55. My IA had already done an Electroair install on his V35B Bonanza and a couple other Bonanzas but hadn't done a Baron yet.

We phoned an IA friend, Michael Thompson of AVSTAR, who had previous installation experience with an Electroair system in a Baron. He told us what we already knew that there was no engine bay real estate for the monster ignition coil and his install used the engine nacelles for the mounting of the coils. Michael stated that his install was on the forward facing bulkhead of the nacelles.

After this conversation my IA and I looked at the nacelle cavities and realized that there are outboard inspection panels that would allow anchoring of the coils within the nacelle cavities while allowing for an easy penetration access through the engine bay firewall into the engine bay for the plug wires to reach their cylinders. We did not see a good way to mount the coils in the outboard sections of the inspection panels and besides, the left inspection panel opening had the ground power port structure in the way. Additionally, we could not see a way to get the six plug wires into the engine bay from the outboard inspection cavities.

Entry to the nacelle cavities was made through a factory inspection panel in the top of my nacelles. 

Sizing Up the Coil Mounting Space

We chose to tap the coil mounting plates that come in the kit to 5/16-24 and fitted with AN5H-4A bolts then safety wired to secure the coils to their home in the nacelles. This allowed a one-handed coil placement and install inside the nacelle, while the other hand threaded the AN bolt into the mounting plate.

One can also choose to simply use nut and bolt hardware to secure the coils to the nacelle sidewall.

Tapping the Coil Mounting Plate 5/16-24

Click to Enlarge Above Images

The positioning of the coil for mounting position is critical since you have to insure that you have adequate space within the top and bottom of the cavity to install the top and bottom plug wires onto their respective towers. My install kept the coil mounting plate parallel to the angle of the riveted top reinforcing section. My measurements are pictured but since these are handmade aircraft you would be wise to measure 3X and drill once!

In order to mount the right engine coil to the outboard side, two fuel hard lines had to be removed and replaced with flexible lines from PHT in Tulsa.

With the coils mounted we now focused our attention on the firewall penetration for the ignition wires. Our plan was to cut a 2.125" hole in the firewall in conjunction with a 2.5" sheet metal disc with six (6) 0.50" holes for the plug wires that will be fitted through 0.50" OD Tygon tubing for chafe and cross fire protection. 

After another bout of head scratching my IA and I selected the firewall penetration location for the 2.125" hole to be the area aft of the mixture arm on the throttle body. This allowed angle drill tool access to create the hole and hand working space to manipulate the plug wires and secure the tygon tubing with wire ties.

Both Electroair and my IA recommended that the Electroair system be connected to the lower plugs since the lower plugs tend to foul more easily and the high energy of the EIS can manage minimizing that fouling. I'm all for anything that reduces the amount of times I have to remove the bottom plugs in my Baron for cleaning!

The plug wires were mounted to the coil towers in accordance with the provided instruction manual (pay particular attention to the Continental diagram in the instructions) and cut at their cylinder lengths (with some added service loop) and then terminated with the provided hardware.

Based on the RE coil location and firewall penetration location the supplied lengths of wire made the following RE wire combinations: 6 + 1, 5 + 3 and 2 + 4.

Based on the LE coil location and firewall penetration location and supplied lengths of wire, we were only able to make cylinder 2 + 1 out of one wire leaving us with only 2 wires in the original kit to fit up 4 cylinders. As a result, we requested and received two additional plug wire lengths for our Baron installation.

To protect the plug wires from exhaust pipe exposure they were routed inboard of the engine mount utilizing 8mm plug wire separators to keep things tidy.

We chose to mount the Electroair Magneto Timing Housing (MTH) in the left magneto position of both engines. This choice left the conventional right magneto to fire all the top plugs. Be sure to do your MTH timing procedure per the Electroair install instructions and use the #1 cylinder for determining your TDC position! Also, the magneto hold down ears may need to be trimmed to fit the MTH profile.

My IA had success shortening his remaining magneto wires on his V35B and reinstalling the spring "stingers" but I wasn't as fortunate. I'd recommend using the existing "unmolested" harness and just spreading the additional wire out in the top of the engine and cylinders.

The next pair of components to be mounted were the electronic controllers. We chose to mount the controllers on the nose baggage aft wall on top of the heat duct channel using rivnuts which also allow for airframe grounding points for the wiring harness coming into the controllers.

Now comes the tedious part - the pulling of the wiring harnesses through the airframe to their respective homes .

NOTE: Upon examining the supplied length of wiring harness for the controllers to the coils and MTHs, we requested an additional 6' length for the RE and 8' for the LE. This turned out to be more than adequate and gave, what my IA called, a comfortable service loop that we coiled in the baggage compartment.

We started at the controller and pulled the four-pin connector for the coil (with red power wire) and the MTH harness up through the top of the nose baggage and into the back of the instrument panel and then down to the leading edge of the wing where the engine control cables exit and then up into the engine bay. The RE had an unused grommeted access hole in the firewall that was used for the coil wires. The LE used the center hole of the coil wire disc to make entry of the wires through the firewall. It's a good idea to use appropriate chafe protection where the wiring passes across the sheet metal openings.

Engine monitor wiring makes for tight quarters in the leading edges . 

RE Wiring To Engine Bay

LE Wiring To Engine Bay

After pulling the coil and MTH wiring to their respective positions in the engine bays, I moved to pulling the control switch wiring, LE and RE, into the cabin to the pilot's side, exiting at the OE position for the magneto switches that are mounted into the OE escutcheon.

After removing the magneto switches we were left with this huge nest of wires likely due to a previously removed Shower of Sparks system .

Fortunately, my IA is also an ace avionics and electrical guru. The provided Electroair control panels required identifying the magneto P-leads, grounds, bus voltage when the master key switch is turned on and starter relay wiring.

The starter button connection screws were worthy of a watchmaker! Thankfully, this was no big deal for my IA's wiring skills.

NOTE: During my IA's wire sleuthing we discovered that my SN starter relay hot wire was an UNPROTECTED wire (J1A18 and J2A18) direct from the bus. The wiring diagram calls out this unprotected wire to be in SNs prior to TE -329 and prior to TC-1029. This is confirmed with the factory wiring diagram (see below), which showed the later SN aircraft starter relay hot wire (J1A18) routed through the Cabin Lights 5 amp CB. My IA was happy to correct this and route the starter relay hot wire through a 5 amp CB.

Each Electroair system requires a 2 amp CB for each controller and a 10 amp CB for each coil (this should give you .

Power for the CB panel was taken from the bus side of the Master Relay which is located in the aft right corner of the nose baggage compartment.

We chose to make a CB mounting panel for mounting in the nose baggage. My IA's preference was to have the CBs inaccessible in flight, preferring to have any CB tripping resolved on the ground. Additionally, the wire length from the Master Relay (in the right side rear corner of the nose baggage) to the CB panel was a short run. Your IA's CB location preference may vary.

Below is the dimensional sketch I made to create my sheet metal replacement control panel mounting plate. It will soon be replaced by a 3D printed panel with 0.375" thickness that will create the offset from the left outside panel that the factory escutcheon incorporated. Click HERE for the 3D printing .stl file.

Electroair Scale Sketch for Panel (Download & Print on 8.5x11 Paper)


Electroair Panel Drawing w/Embedded CBs

  Fabricated Control Panel Mounting Plate

The next pair of connections involved the 1/8" ID hose to feed engine MP info to the controllers for timing advance per Electroair's advance curve. It was found that there was enough play in the MP instrument hard lines to place the necessary "T" in the line to tap into MP info.

The below fittings info is courtesy of Electroair research. I employed Option #1:

 

Final installation pics:

As of this writing (28 February 2025), I have only done ground checks and relatively short flight checks, one at 10,500' and a short fuel run for $4.55/gal gas at KXBP.

Initial System Observations

• Incredibly intense install labor component for twin-engine (owner assisted install is highly recommended for best economics).
  
• Cold starting and hot starting are indistinguishable. Cold start priming and starting SOP achieves easy hot starts.
• Seat of the pants takeoff power feels stronger
• At 21gph, only one cylinder, RE #2 cylinder hit my 380°F action temp, whereupon, the mixture was leaned to 20gph. This was likely due to the more complete combustion of the fuel, the consequence of which is creating additional heat (DUH). Extended long distance flights will be needed to make an assessment on fuel savings potential.
  

Below are videos of the initial short flight test at 10,500' leaned to 21gph (183KTAS) and 20gph (174KTAS).

YouTube

B55 Electroair Ops Check @ 10,500'/21gph/WOT

 YouTube

B55 Electroair Ops Check @ 10,500'/20gph/WOT