Tony's right. The SD-8 is actually the better fit to the 914, since it
loses only about 40% of its
capacity at normal cruise speeds and 15% at max RPM( the factory alternator
has full output at normal cruise speeds ).
The SD-20 loses more than 50%, so is a pretty big chunk of lead on top of
the engine for not much
oomph. The vacuum PTO needs a 0.7:1 ratio instead of a 0.54:1 ratio to
match Lycoming PTO speeds, for
which the SD-8 and -20 were designed. Either one should be considered only
a secondary source. The belt-driven
40A front alternator doesn't fit under the Europa cowl.
The only other person I know who solved this problem was Jim Nelson, who
mounted a 40A alternator onto the
engine ring mount with a flexible custom drive boss to the back of the main
crankshafts. Wow.
Although full redundant electrical systems would be great, I wonder how many
times, or how many of us, will EVER
fly our micro-chariots more than an hour away from a suitable airport. Why
load the plane down with 10 lbs of
unnecessary weight when a suitable VFR/emergency IFR electrical system is
more in keeping with the design mission of
the Europa? Night flying is about the only reason I can see that the basic
Rotax alternator wouldn't be enough to
handle a very nice panel. Those strobes and nav lights burn 13A just by
themselves.
Shaun
A207
----- Original Message -----
From: "Tony Krzyzewski" <tonyk@kaon.co.nz>
Subject: Re: Looking down the road at batteries
>
>
> > Thanks, Tony! I also see from a search that B&C makes a 20 amp version
> > that
> > fits on a vacuum pump pad, also. It's a bit more money, but would give
> > me
> > enough electrical power to really go crazy. It's the SD-20 alternator
>
> There isn't a lot of depth behind the vacuum pump drive on the Rotax so
I'd
> check that it is actually going to fit in the space before spending any
money.
> The 8A version fits in with not much clearance behind it on the 914.
>
> The same reduced speed factor will come into play with this unit so don't
plan
> on having the full 20A available.
>
> Tony
>
Date: Sat, 2 Feb 2002 16:11:54 GMT
Subject: Majordomo results: get-immediate forum archive/forum.200201
From: majordomo-owner@europaclub.org.uk
>>>> get-immediate forum archive/forum.200201
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