If you have ever had a Magneto coil go bad in the air, you’ll know it’s a dramatic & disturbing way to have a flight cut short. Old and overheating coils fail when adjacent layers of the internal wax/foil capacitor, deep in the winding, experience a short.
The run-up was fine but now, 20 minutes later, you’re at altitude, you’ve just completed some high power maneuvers when suddenly the engine dies completely or vibrates very badly. Reduced power may make the vibration disappear, but back on the ground and cooled down, the motor gives no evidence of any malfunction.
There’s no denying unreliable, aging coils are a potential safety issue.
The Yak Collection is proud to announce exclusive distributorship in US & Canada for Richard Goode Aerobatics’ new magneto coils.
In re-engineering this critical component, RGA obtained full EASA Certification through rigorous testing, also demonstrating 15-20% greater coil power output. Considering EASA is Europe's equivalent to the FAA, being able to certify a replacement component for a Russian magneto in 2020 is a real achievement.
Your unique coil is serialized and comes with its certificate of compliance in the package.
Different diameter mounting screws
These new coils have slots to suit one of two mounting screw sizes - so before ordering, determine whether your magneto has M5 or M3.5 screws holding the coil down into the magneto body. This will decide whether you need a coil with wide or narrow slots (see picture above) then use the drop down menu to choose the correct coil for your Magneto.
It was once true that fixed timing M9-F magnetos were all threaded for M5 coil mounting screws; while automatic advance / retard M9-25 and -35 magnetos, (and Chinese magnetos on Houssai engines), all had M3.5 screws. However, Magneto bodies with either thread size can be rebuilt up to either type of Magneto at overhaul, and this is exactly what has happened over the years.
Please don’t guess your coil’s slot width because electrical ignition components, while warrantied for performance, cannot be returned.
With the exception of the mounting slot width, the performance of all RGA Magneto coils is identical.
slot width identification
To easily identify your coil’s slot width you will need a flat bladed screwdriver that has a square or hex shaft, plus a wrench that fits.
Temporarily remove the P lead, above ( and make a mental note about how this affects anyone touching the prop) then remove the two rearward facing, long countersunk slotted head screws that secure the magneto coil cover.
The tight accessibility for the screwdriver’s handle near the engine Bearers, proximity to the oil cyclone for the left Mag, plus the generous contact area on those countersinks mean that mere mortals will find it hard to undo these two cover screws without the aid of a wrench on the screwdriver shaft.
Now, with the cover removed, finally you can compare the coil slot width against the images above and order the correct part with confidence.
removal and installation
Let’s proceed to removal and installation, once your new coil has arrived.
With the coil cover (mentioned above) removed, there is easy flat blade access to the two tab washers and hex head screws securing the coil.
To disconnect the coil electrically, you’ll also have to remove the larger horizontal cover over the rotor & distributor, which is safety wired. These covers have three hex head screws horizontally and four on the vertical front facing area where the ignition leads exit...a 9mm wrench takes care of all of them (and their heads are slotted also).
Take this opportunity to check that the pencil can be rotated freely. Lift up the distributor and rest it out of the way as you withdraw the pencil upward - just for the duration of swapping out old & new coils.
The Coil’s wire lug passes up through a hole in the magneto’s internal horizontal wall, where it attaches to the points; so release that screw....
...and if you have already removed the 2 screws holding down the coil, the old coil may be removed downward.
Installation is the reverse of removal and don’t forget to install the Pencil after the new Coil’s lead has been reattached to the points.
The lug from the capacitor on the new coil should be pushed onto the Hex head screw first, followed by the locking tab washer.
No need to get medieval with these slotted-head hold down screws, normal hand tightening with a screwdriver will suffice, in view of the security provided by the locked tab washer.
View RGA's full installation document here.
(Appropriate mounting screws and tab washers for your coil are supplied in the package.)
Replace and safety wire both covers as necessary.
* * * * * * * * * *
Please contact us prior to purchase with any questions you may have at 619 933-2571 since all sales of ignition and electronic parts are final.
TYC also stocks new RGA Rotors and Pencils for these Magnetos.
For Coil sales outside the US and Canada, please contact RGA here.
John flies out of KSEE whenever he can scrape together a few bucks to fill the tanks