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Janekom 01-03-2022 01:32 AM

Dual Plasma questions and poll
To the brain force out there. I am trying to educate myself a bit.

I have this perception that the Plasma ignitions systems are very reliable. I know of at least two RVs with dual Plasma systems and no backup battery.

I am sure there are many arguments for a backup battery and there are also those who will say it is not needed on a day VFR ship.

Your opinions will be much appreciated.

Walt 01-03-2022 08:01 AM

It's not about the reliability of the ignition per se, it more about the reliability of the aircraft electrical system.

JDeanda 01-03-2022 08:59 AM

We Went Simple
Installed a Plasma III on our RV-6 and kept the left magneto. There. Nearly all the advantages of a dual Plasma with the simple, lightweight backup of the magneto that does not notice or care if the airplane electrical system fails.

Vansconvert 01-03-2022 09:26 AM

I am running dual plasma II's with dual batteries and dual alternators and a bus tie. I totally agree with Walt. Somewhere along the way I read here where someone broke a alternator belt which ripped the wires out from the trigger mechanism up front and when that happens you have nothing.

Carl Froehlich 01-03-2022 09:32 AM

My first RV-8A started out life 20 years ago with dual Plasma II+ ignitions, and a power system designed to make sure at least one always had power.

I removed this ignition at ~300 hours after multiple failures, two in flight. That airplane has been flying now for ~1000 hours on dual pMags that have been flawless. I installed dual pMags on my current RV-8 (~270 hrs) and there is a single six cylinder pMag and standard mag flying on my old RV-10.

Perhaps my experience with Lightspeed is not typical, but I can report other Lightspeed users I know have either gone to pMags or back to standard mags.

Also I wonder if the product has been revised over the last 20 years.

I do not have any data to demonstrate if the Plasma III is more reliable than the II+. Perhaps others can comment.


bjdecker 01-03-2022 09:39 AM


Originally Posted by Carl Froehlich (Post 1579566)
I removed this ignition at ~300 hours after multiple failures, two in flight.


Did you ever get to true root cause of your ignition failures?


Carl Froehlich 01-03-2022 09:46 AM


Originally Posted by bjdecker (Post 1579569)

Did you ever get to true root cause of your ignition failures?


Yes - PM me if interested.


Dan 57 01-03-2022 09:50 AM

Dual Plasma II with 2.3Ah back-up battery.
Been running flawlessly since 2005, 1’100 hours.

JDeanda 01-03-2022 10:35 AM

Thread Drift....Sorry
Our Plasma III has about 200 hours over about, um, three years I think. Absolutely, perfectly flawless. Klaus saw my installation, in fact made up the spark plug wires for me and insisted on being present for the first start. Complimented me on the installation and commented "Looks like you read the manual."

Carl Froehlich 01-03-2022 11:35 AM

One other comment, if you run dual ship power dependent ignitions I strongly recommend a robust electrical power design. Perhaps they exist but I have not seen a “per instructions” backup battery install that satisfies my risk tolerance. Specifically these backup battery schemes do not provide adequate electrical reserves (should be more that 90 min for me), many do not provide indication of backup battery health during normal operations, and I’ve found some of these backup batteries to be dead in flying airplanes (as in installed a decade ago and forgotten).

It can be done, but hard with just a single ship battery as your base. I suggest there are many advantages to a two identical ship battery design that uses no backup batteries (either for the engine or the panel).

Whatever you do test it! You don’t want to find out if it works or not when you really need it. Make sure whatever switch manipulation are needed (if any) to keep the fan running are clearly documented in your POH Emergency Procedures - and routinely tested.


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