30 Dec 05 - Alternator Installed, Electrical Equipment Shows Up

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B&C L-60 Alternator. This will crank out 60 amps/14 volts. This is a bit overkill for this airplane, perhaps . . .
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There's the belt on there, and the mount. Note that you've got to pull the starter off to get the belt on there.

Size of the alternator: there were two B&C Alternators we were trying to decide between, this one (L-60) and the slightly smaller size - the L-40, I believe. The one that we ended up getting is a bit more expensive and adds a few pounds, but puts out more honk, so to speak.

The way we've been told to compute what size alternator you need is to make sure that it can keep up with recharging the battery when 80% of the maximum draw is put on the entire electrical system. Pitot heat, landing lights, etc., everything. Apparently 80% is a good number for this because odds are, you won't be running at more than that for any extended period of time. The L-40 was pretty close to this number, but there are still some variables that we don't know - are we going to add pitot heat, how much will that draw if we use the yet-to-be-released Dynon heated pitot tube, are we going to keep the 100W landing lights or put 55W landing lights back in there . . . there were a few variables, and the larger alternator means that even if we go with the higher-power options on all of those, we should still be okay.

All that to say - with a few less variables and a little trimming, you probably can get away with a slightly smaller alternator. Actually, I think most folks do.


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Entire thing on there. According to the belt, the engine needs to be run for 5 minutes, and only after that can then the tightness of the belt can be adjusted. Don't safety wire it yet, I guess.
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More B&C stuff - from lower left - grounding block, wig-wag flasher, alternator controller (among other things it does), and one of the pile of fuse blocks that is on its way to us.
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Reference (for me as well as everyone else) - this is the belt that fits for this engine/alternator combination.

If you look carefully, you can tell that the alternator actually is contacting the orange oil hose that would be for the prop control if we were using a constant-speed prop. It's easily seen in the second picture, and you can see how the alternator touches it in the third picture. Is that okay? Time to ask Mahlon, and here's his response:

Garrett,
The alternator is fine the way it is, you might put a piece of chafe
strip where it touches or a small bead of RTV to keep it from chafing
against the alternator housing, which also works great. The hose
touching the alternator, or anything else for that matter, is OK as
long as they won't vibrate against each other and cause the line to
be chafed through. Normally even if this happens it is easy to see as
the fireshielding gets rubbed first, and it takes a lot of rubbing
over many hundreds of  hours of operation, to get through it before
even getting to the actual hose.
Good Luck and Happy New Year,
Mahlon
1-800-624-6680 ext.305
www.mattituck.com




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