On 3 Sep 2003 14:12:04 -0700, (Paul Lee) wrote:

Barnyard BOb -- wrote in message . ..
.... A 16 amp-hour
Odyssey is going to empty out pretty quick unless one
is willing to start the blades rotating by hand. ....

I am using the PC680 Odyssey battery for starting
a 10.5/1, 220HP Franklin engine. It has no trouble
cranking the thing. True, at 225amps cranking the
battery won't last more than a few minutes. But if
the thing does not start in the first 5-10 seconds,
there is something else wrong.

That's an interesting application. The 680 is only 15 pounds and it's
small in volume, that's why I like it. I got a hold of a couple 35
Amp-hr Gel Cell batteries today from a buddy (brand new out of the box
and he just gave them to me since his application disappeared). I'm
going to make an APU out of them and use them to hook up in parallel
during my starts. That way I'll have plenty for the flying day.

My real problem here, and I haven't talked about it, is that my blades
aren't tracked properly. I've painted one tip red and one black. You
can't track them without flying the damn thing. In flight, you look
at the tips and see what blade is above the other. Then you land and
reduce AOA on the high blade, spool up again and go for another try.
It's an empirical thing until you get it dialed in. The problem with
a Walmart motorcycle battery is that I get about three starts from it
with a 30 minute charging time between each start and the battery is
toast since it deep cycles to full discharge. That battery is simply
not designed for what I need to do.

Another problem is that I have to crank the engine after I start the
main rotor blades and get them into autorotation facing into the wind.
If there is no wind, I have to taxi to make relative wind and I have
to start the Rotax 582 to do that. I can't do that without a Mambo
battery.

BWB