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A1B6 24V to 12V

A

Archie167

Member
Hi all,

After some more advice on the next stage of my project. Have an A1B6 that’s been bulk stripped for IRAN and I need to convert to 12V set up. I will order a Hartzell constant speed prop (C2YR-1BFP/F7497-2 ,72 in. dia) from Vans but the ignition set up may influence that - not sure? So my queries:

1. Alternator. I have a PP/Hartzell AL12-E60/B that came with the FF kit but I believe having read another post this may not be the best one to use which is frustrating becomes it becomes a large and expensive paper weight. A friend of mine also had one that failed inflight. His suggestion is a B&C with external voltage regulator. Thoughts?

2. Starter Motor? Any recommendations appreciated.

3. Ignition system. Existing magentos will need to be switched out I assume being currently a 24V system. Interested in electronic ignition but there’s pro and cons and I’d prefer not to run a second battery as backup. Interested to learn some opinions or experiences with this.

4, anything else I haven’t considered?

Once again thanks in advance.
 
I also have the A1B6 - my thoughts with no building or particular expertise:

1. I did not build my RV, if I were in your position I would go with the B&C eternally regulated Alternator. I recently replaced my alternator with the same PP you have, but that was only because I didn't want to re-do the wiring etc to fit the external regulator. If you can do it at the build stage I would go that way.

2. No thoughts on the starter, sorry.

3. I have dual e-mags (the ones with the internal generators, also referred to as P-mags). I love them and would recommend those. I also have a B&C backup alternator mounted on the back of the engine and a single EarthX battery. so far, so good with this setup.
 
Your current mags don’t use aircraft voltage.. so they don’t care if you are 12 or 24 volts. It’s just the starter and alternator.
 
Taltruda said:
Your current mags don’t use aircraft voltage.. so they don’t care if you are 12 or 24 volts. It’s just the starter and alternator.
Click to expand...
I was wondering that but thanks for the confirmation. May need to keep them for now due budget but the e-mags sound like a great upgrade at some point. Thanks.
 
Magnetos aren't system voltage dependent, unless you have a "shower of sparks" or other augmentation system.

Plane Power is fine - just needs a blast tube, and check the rotor balance. Spin it up to a few thousand RPM and see if it chatters...
 
bjdecker said:
Magnetos aren't system voltage dependent, unless you have a "shower of sparks" or other augmentation system.

Plane Power is fine - just needs a blast tube, and check the rotor balance. Spin it up to a few thousand RPM and see if it chatters...
Click to expand...
Thanks.
 
I also run an A1B6. I'm using a SkyTec 149-12XLT. Count the teeth on your starter ring gear. For some reason, when I bought this plane, it had a 122-tooth starter ring gear on it and a 149-tooth starter. Needless to say, the starter and ring gear assemblies were both replaced due to galling caused by mismatched gears.

And don't be fooled by people referring to the starter ring gear assembly as a "flywheel." I can assure you, it is not a flywheel. It doesn't operate anything like a flywheel. In fact, the only trait that a starter ring gear assembly shares with a flywheel is that they're both nominally disk-shaped and rotate about their axes during operation. I don't even know how such a term for this device could have so deeply penetrated the aviation vernacular.
 
Archie167 said:
Hi all,

After some more advice on the next stage of my project. Have an A1B6 that’s been bulk stripped for IRAN and I need to convert to 12V set up. I will order a Hartzell constant speed prop (C2YR-1BFP/F7497-2 ,72 in. dia) from Vans but the ignition set up may influence that - not sure? So my queries:

1. Alternator. I have a PP/Hartzell AL12-E60/B that came with the FF kit but I believe having read another post this may not be the best one to use which is frustrating becomes it becomes a large and expensive paper weight. A friend of mine also had one that failed inflight. His suggestion is a B&C with external voltage regulator. Thoughts?

2. Starter Motor? Any recommendations appreciated.

3. Ignition system. Existing magentos will need to be switched out I assume being currently a 24V system. Interested in electronic ignition but there’s pro and cons and I’d prefer not to run a second battery as backup. Interested to learn some opinions or experiences with this.

4, anything else I haven’t considered?

Once again thanks in advance.
Click to expand...
I personally wouldn’t put the pp alt on my plane. Their longevity record is very mixed. Lots of guys have issues like your buddy and lots of guys get long service. That said, because there are plenty of people in your buddies situation, there are lots of folks looking for replacements. Should be able to sell it quickly. Because they have almost doubled in price in the last couple years, if you bought yours a few years ago, you can probably sell it for more than you paid for it.

You will need to look at all of your engine sensors. If the instruments were 24volts, the sensors may not work with 12volt instruments. Probably ok, but need to check.
 
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Thanks it’s a new build so all instrumentation etc will be set up for 14V.

Does anyone have experience with B&C Starters? I may order one with the alternator.
 
As others have mentioned, magnetos don't use ship power, they don't care about voltage unless you're using the electric "Slick start" (old name "shower of sparks) with a "retard" mag (standard on an IO540).
For electronic ignition without a redundant electric supply, there are a couple of options:
1."P mags" contain their own internal generator.
2. Lycoming is now selling a certified (STC, etc) electronic ignition. For aircraft with only one battery they recommend (mandatory for certified planes) that you just use one electronic ignition, and retain one mag for back up. Of course you could go the same philosophy with any of the electronic ignitions out there.
 
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