08/05/2025
A good read for customers thinking about Electroair systems.
We've been getting calls and emails from pilots asking us to compare our system to Surefly, and here was our response:
Thank you for your email. As you can imagine, we are asked this question fairly frequently. We have not specifically inspected their unit, however, there are a number of things that can be determined by the installation of a Surefly system and their STC limitations.
First off, let's talk about our system in general terms and then we can go through a comparison. Our system is a very high energy, variably timed ignition system. The energy we are able to deliver to the spark plug is ~70,000V and has a duration of ~20deg of crank rotation. The timing in our system is varied based on MAP, which is a good way to measure air volume inside of the cylinder. You need to have both elements, high energy and variable timing, in order to achieve the performance gains we claim.
Spark Energy: Based on the fact that Surefly is using the original magneto harness for delivering the spark energy to the spark plug tells me that the energy output from their unit is no better than a magneto. Magneto harnesses use a 7mm wire that has an outer metal shield. In a high energy ignition system, this kind of spark plug wire will break down quickly and will arch internally causing radio noise. The automotive industry went away from the externally shielded wires several years ago when HEI systems were first introduced. This why we supply the 8.5mm spriol type wires we supply with our system that have a substantial noise suppression characteristic.
High spark energy is critically important in aircraft electronic ignition systems because as aircraft go up in altitude and the air density decreases, the ability to ignite the fuel/air mixture becomes more difficult. A higher energy ignition source ensures a complete ignition of the fuel/air mixture at both high and low altitudes.
STC Limitations: Surefly has two specific limitations on their STC that can give us some insight into how their system operates (and frankly, creates some concern).
The first one is the requirement to have sophisticated engine monitor equipment in order to use their timing advance feature. This suggests to me that the FAA is concerned that the Surefly timing advance needs to monitored so that engine temps do not get out of control or to prevent the engine from suffering from detonation. Our system does not have this limitation.
The second limitation that the Surefly system has is that it can only be used with 100LL fuel. Again, my interpretation of this limitation has to do with detonation. I would surmise that because of the low energy nature of their system, the detonation testing showed problems with lower octane fuels. This is certainly one of the problems that magnetos run into when using lower octane fuels in higher compression engines (think big bore Continentals). A high energy ignition system, like ours, does not run into this kind of detonation problem.
Maintenance Claims: This is Surefly's biggest claim is that they have a maintenance free system for 2,000 hours. Namely, that there are no recurrent maintenance requirements like 500-hour inspections and nothing to adjust. Our system has the same feature. One big difference that I see is that the Surefly system needs to be completely replaced at 2,000 hours. Our system does not.
Performance/Fuel Savings Claims: The Surefly system has never claimed any appreciable fuel savings or performance gains - at least none that I'm aware of. Several customers who have interviewed the Surefly representatives at either Oshkosh or Sun N Fun report that Surefly does not promote any kind of fuel savings. The big features are a simple installation and no maintenance.
We have consistently reported and promoted fuel savings and performance gains (particularly at altitude). We have on our website several PIREPs that describe exactly those kinds of gains. In normally aspirated engines, we consistently see fuel savings of 10-15% when the engines are operated according to the engine manufacturers specifications. We have even received reports of increased airspeed for some airframes (Bonanzas in particular) while saving fuel. We have had reports of being able to operate turbo-charged engines at leaner fuel settings than before. And the list goes on.
My question has been that if you were going to consider changing from a magneto to a more modern ignition system, wouldn't you want to get all of the benefits available? In other words, how much of an advance is it really to go from a mechanical magneto to one that is powered by the B+? Why not go all the way and see how the airplane can really perform? Compared to some other engine modifications, like tuned exhaust or even just a bigger engine to be able to see performance gains, our ignition system seems like a pretty reasonable investment to be able to realize some of those gains.
I hope I wasn't too long-winded, but your question seemed like a great opportunity to share some of the things that we have been observing here. Please let me know if you have any additional questions.
