Plane-Power Experimental Alternators
After a long search, I've finally found the Primary
alternator I'm going to put on my RV-10. In the future, I'll also
be adding a backup alternator, but probably not until after I'm flying.
I had never heard of Plane-Power before, as they're a new
company. But then I ran into them at OSH 2005, while I was
actually on my way to B&C to buy their Alternator, regulator, and
backup alternator setups. I stopped by the booth, and saw their
alternators. They explained that they were in the process of
doing a certified alternator that would be certified before the
Experimental alternators would be released. The FAA/PMA process,
as it turns out, has just completed on 9/22/05, so they held to that
statement, and now their experimental alternators should be available
within the next week. The experimental alternators are the same
as the certified units, with the exception that they have built-in
Overvoltage protection. This also got my attention, because
there's a ton of discussion on the Aeroelectric list as to what method
is better, and I started thinking about how this alternator plays into
that game. To me, it would seem that with all the diligent
testing they've done, that I couldn't go too wrong in buying a top
quality alternator, and with it being a new design, it could not only
incorporate new technologies, but would have undergone recent testing
as well. So, I was sold enough to put my name on the list and
delay my purchase from B&C. It should be noted that the cost
of these alternators is *well* under what B&C gets for their 60A
alternator. Also, the Plane-Power alternators come with
*everything* you need. They even include the wiring harness, boss
mount, brackets, and the alternator belt. (** Note: Don't final-torque
your prop until you put your belt on...you need to have the prop off to
install a belt.) One other side note: These alternators
use dual fans, one front, one rear. The rear one sucks air in the
back and vents out the side, and on the 70A you can add a cooling blast
tube to assist it in even more cooling. (The back is the side that
really needs the cooling) The front side sucks air in and
exhausts out the side as well, so it should have plenty of cooling air
circulating through it at all times.
As for my backup alternator, I still plan to purchase one, but they
threw a wrench into that plan too. I inquired as to the
availablility of a standby alt. for the accessory pad, and they said
that they hope to have one ready next year. That was enough for
me. The company really seems to be true to their word. So
for now, I can live without it while doing my first year of flying.
It'll take me a while to be comfortable going into any of the
extreme IFR situations that would warrant such a system anyway.
And besides, I do have a dual-battery system that should allow me
to operate for quite a while without an alternator. After I do my
final load testing, I may even decide not to buy a standby alternator
if things test out well enough.
Fitting the 70A "Big" alternator into the RV-10
First, I fit the 70A Alternator to check for cowling interference.
They had warned me that in some other RV installations, people
needed to buy the small 60A because of the cowling interference.
Being 3 lbs lighter than the 70A, I think the 60A would be a
great option for many builders, but I have reasons why I'm willing to
accept the trade-off of heavier weight. I don't really need the
extra 10A, but the difference does buy you a couple more benefits.
- The 70A alternator turns slower, and thus runs cooler
- The 70A alternator comes with an air blast-tube adapter for cooling
- The 70A alternator should provide for a little more margin of ultimate power if I need it
So, my logic is that just from a reliability standpoint, I'd rather
have the cooler running alternator, if it fits. On my first
fittings, I didn't want to pull the prop, so I used an old worn-out
Lycoming belt that I snipped in half. It was roughly similar in length
to the belt supplied. The most common place for interference with
my cowl would be at the bottom of the alternator pulley. See this diagram for more info.
As it turned out, even if I adjusted the alternator to the absolute
bottom of its travel, I have 1/8" clearance, and if adjusted tightly
with the supplied belt, I have 1/2" clearance, so there is plenty.
Fitting the 60A "Small" alternator
Then I installed the 60A just to take some photos in case other
builders wanted to see how it looked. At the point where I knew
the 70A would fit, I knew that was the one I wanted. The small
one is very nice though. It does give additional clearance and I
think would be a great option if you're worried about the extra 3 lbs.
The pulley is smaller, so it does turn faster during operation.
Wire Routing Photos
These photos are just for reference for routing the
wires. My estimate is that it will take about 2' of wire from the
alternator to the rear of the engine, and another 3' or so to get to
the left side of the fuselage. Then about another 2.5' to get to
the area where an alternator master switch would be. Maybe throw
in another 8" if you want to route the wires all the way back to
the firewall, and another 4' or so if you want to run the wires across
to the right side of the panel for the circuit breakers. Overall
length, probably 12' max.
Photos for Reference on bracket
The only place where I found an issue at all, which is very minor, is on the adjuster
bracket. You might notice that the bracket has a small "jog" bent
into it, that's about an inch long, up towards the upper mounting bolt.
The problem is, this jog should be about 1" further out from the
mounting bolt, or it won't lay flat against the engine block. I
think a thin shim washer behind it would be OK. I'm currently
going to check into the arm angle required to match the front/rear
mount of the alternator, to see if the best fix is the shim, or if it
needs to be a re-made part. They are very interested, as there is
some variability among Lycoming blocks with various number
designations. Mines an I0-540-D4A5. It sounds like if it
needs to lay flat, they would want to do what's best and remake the
arms. Great people to work with. I'll post more here later
as I find out.