Alternator Conversion For Aerovee

[sonex1566]

Now that's something that deserves a Gold star!
However, I gotta ask....are you still running a secondary ignition system? I was looking at the extra bits welded to your pulley and wondering if they were to do with some form of ignition timing. Great job though, I applaud your bravery!

[GraemeSmith]

How is the crank oil seal holding up with the side load on it?

[Bryan Cotton]

That looks cool. What is the delta in weight?

[jfuerst]

Now that's something that deserves a Gold star!
However, I gotta ask....are you still running a secondary ignition system? I was looking at the extra bits welded to your pulley and wondering if they were to do with some form of ignition timing. Great job though, I applaud your bravery!

It's still the stock secondary ignition. All the same parts, just a different bracket that holds the pickup sensors.

Instead of having 1 magnet that is picked up 180* apart by two sensors on either side of the pulley I now have 2 magnets that are 180* apart -- One on each "side" of the belt. Then I stacked the pickups on top of each other so the bottom one sees the magnet on one side of the belt and the other sees the magnet on the other side of the belt 180* off. The welded on bits you see - One of them contains a magnet, the other just balances out. The "balance" one has a magnet on the other side of the belt corresponding to the pickup on the bottom of the stack.

This just made the machining of the timing brackets to adjust timing easier and a little lighter. I loosen 2 screws (instead of 4,6, or 8) and slide the pickups around just like before, only they are both located together as a stacked pair. I'm not sure if it was worth doing it this way. I was worried about cable management by the belt and ease of adjusting the timing. If I did it again I'm not sure which way I'd go. It makes adjusting timing easier than it would be if the sensors were on opposite sides of the pulley, but I do now have "dog ears" that could catch a loose wire, where without them likely the wire would just rub... Alternately I could have made the pulley rib (where the nubs are) wide enough for a magnet and still maintained a smooth surface, but I didn't think about stacking them until after I machined the pulley and it was too late.... Thus the ugly nubs.

[jfuerst]

That looks cool. What is the delta in weight?

About 2 lbs more... I removed a smoke maker reservoir at the same time, so in my mind, in this situation, the plane ended up lighter. I think if I really spent more time on finding/paying for a lighter alternator, machining an aluminum alternator pulley, maybe find aluminum winding etc. possibly could be less than a pound difference.

I kind of like that an alternator could be sourced from any parts store or even amazon if something happened that stranded me somewhere.

There are definitely some potential downsides:
1) There is that spinning mass and belt exposed to the back of the engine instead of being covered safely like the factory solution.
2) belt could break
3) wiring could become entangled and broken

4)

How is the crank oil seal holding up with the side load on it?

--- So far so good... Hadn't thought of that....
5) .... there is only one of these....
6) If it goes catastrophic and I die, everyone will say it's my own stupid fault.... And they'd be right.

Its the best and worst of experimental aircraft all in one little package.

[lakespookie]

This is amazing and pretty close to what i had in mind as one possibility assuming enough space that setup is very clean and looks amazing. The one reason i was thinking direct drive to a pully or the alternator was to not side load the crank. That being said the side loading should not be to bad as long as you don't over tighten the belt i am interested to see some more pictures of that installation if they are available.

[scotttro]

Second the "more pics". I've managed to commit to every imaginable electronic device in my Waiex, and am a bit concerned about draw. A significantly larger alternator would be desirable.

[Bryan Cotton]

If side loading the crank is bad, somebody should tell the VW bug guys.

[lakespookie]

I assume you are using the alternators internal regulator can you confirm?

[Bryan Cotton]

Attached is a PDF of my Excel file of my electrical load analysis which I used to "work backwards" and get a result that would work with the 20 amp alternator when I was having issues maintaining a charge in flight at high rpm's with full alternator output.

Graeme,
I followed the link in the more recent post to here. Why do you count the magnetron ignitions as 4A? They are not powered by the 20A electrical system.