E/P and E/P-X Ignition systems, (3301E/P and E/P-X)
Below is the story on our standard and optional ignition systems. The E/P stands for “Electronic /Points” , as it utilizes both. The E/P-X model is internally identical, it just has a few external features to make a slightly nicer installation. We have been producing E/P distributors since 2006. In our numbering system Group 3300 is the engine ignition group. the specific part numbers are 3310 E/P and 3301 E/P-X.
Above is a photo on an E/P-X distributor. The features that make it an -X model are the Weatherpack quick disconnect plug system, the studs holding the cap on (instead of screws) and the fiberglass jacket on the wires. Other than these items, both E/P models are identical.
We looked for a long time before finding the Crane module that is the heart of the E/P ignition. There are many electronic ignitions on the market, but for flight use they have two critical Achilles’s heels: They use many amps of power and they do not work at reduced voltage. The made in the USA crane unit has neither of these issues.
There’s a lot of great automotive electronic systems that work fantastically as long as there’s more than 11.5 volts available and a steady flow of 10 amps to power it. In the world of flying, where you could have an alternator or voltage regulator failure, and be reduced to the amount of electrical power stored in your battery, these electronic systems are not acceptable. Electronic ignitions with computers on other alternative engines have demonstrated as little as 20 minutes flight time after a charging system failure. Many alternative engines that are converted modern car engines have this defect. Most of the people who fly them have never run them at cruise power with the charging system disconnected to know just how short their window is.
A Corvair engine running one of my ignition systems will run for hours on the battery that started it. The points system will work all the way down to the 9 volt range. My Electronic/Points system utilizing the Crane module is a very low power consumer and additionally has the unheard of quality of producing stable sparks well below 9 volts. No other electronic ignition that we tested demonstrated this. The power wire to the crane unit is a tiny 22 gauge wire. When testing distributors on the machine you can run the Crane unit for an hour and it is still cool to the touch.
In the above photo, an E/P ignition running on our machine. This uses the same coils and systems as our Dual Points Distributor with the exception of eliminating the condenser on the electronic ignition’s coil. The photo is from 2006. We have since produced more than 200 E/P units and retrofitted more than 100 D/P distributors with E/P plates.
Success can sometimes come from pioneering work, but it always comes from emulating what has proven to work. Virtually every flying Corvair powered airplane built in the past 15 years has one of my ignitions on it. No aircraft has ever had any type of a forced or precautionary landing made on our ignition system. It works. Period. The only issue builders have has are reversing the red and yellow wires while installing it (this instantly burns out the Crane unit at a cost of $75; bad, but not like burning out a $1,600 Rotax 912 ignition) and we have had 3 people pinch a wire carelessly putting a distributor cap back on. This said, no one has had one of these units fail while flying, and they have been airborne for thousands of hours.
Above is a wiring diagram that shows the basic layout of my ignition system. This page is taken from our 601 Installation Manual, so it includes some of the wiring associated with fuel pumps. This drawing shows the D/P wiring, but the E/P only has two minor differences. The key elements of the design are redundancy, low power consumption and low voltage tolerance.
With our system, notice that you can fail one of the coils or one set of points and still have 100% power available through the backup system. Once every few months, a builder will propose a system that has three pickups and a wasted spark system using three coils and two plug leads from each coil. I know these systems well, and they’re not safe to use in Corvair engines because with three coils and three pickups, you’re statistically more likely to have a failure and when you do, you’ll be immediately down to 66% power. However, the dyno shows that dragging two dead cylinders means you’re really down to 50% power and most Corvair powered airplanes will not climb on half power.
Our EFI page contains a photo of Mark at Falcon’s EFI engine. Note that it actually has six LS1 coils which have built in modules. This is acceptable because a single coil failure will bring you down to 83% theoretical power; about 75% power on the dyno dragging one dead cylinder. This illustrates the point of why it’s acceptable to have single plug ignition on a six cylinder engine. The performance loss of one cylinder on a six is not catastrophic like losing one cylinder on a four cylinder engine. Corvair powered airplanes have taken off and flown on five cylinders on three occasions that I know of without incident. This was due to a missing plug, blown head gasket and missing rocker stud, respectively. You would not get away with this on a four cylinder engine.
The shot of the workbench above shows 85 Distributor bodies neatly stacked. Over the years, I’ve reworked hundreds of Distributors. I’ve had the opportunity to examine many of them after they’ve put in years of flight service. We’ve continuously had running Corvair vehicles to test all types of ignitions in the ground environment. Many of the theories I was taught and believed 25 years ago proved inaccurate or inapplicable to our situation. All that counts in the aircraft arena is what you have proven. Theory is fine for ground debate, but people going flying need proven systems.