Above a 3:1 gear ratio sounded great so I did a little research. According to this Force Outboard Database:
http://proto.piranha.com/motor_specs.php?id=3003
The gear ratio of the 1984 - 1998 Force 9.9HP 2-stroke outboards is 1.57:1.
Perhaps your motor was an earlier (or later) year?
Still on the search for that 3:1 gear ratio...
.
--- In electricboats@yahoogroups.com, Joe Grez <joe@...> wrote:
>
> Our Force 9.9 hp 2-stroke had a higher ratio, above 3 for sure. I'd guess
> that you would want to look into two strokes. They rev higher.
>
>
>
> On Tue, Oct 16, 2012 at 11:45 AM, bb386scn <bb386@...> wrote:
>
> > **
> >
> >
> >
> >
> > The 2.8 to 1 gear ratio in your Honda outboard is the highest reduction
> > that I have heard of. Sorry to hear it didn't work out for your
> > application, but it should work well for a motor with more common RPM
> > characteristics.
> >
> > Has anyone else heard of an outboard with a gear reduction of greater than
> > 2.8 to 1?
> >
> > --- In electricboats@yahoogroups.com, Craig Carmichael <craig@> wrote:
> > >
> > > Hi,
> > >
> > > I converted a Honda 7.5 at one point with an early version of my
> > > "Electric Hubcap" motors (Honda is now sitting with no motor in it).
> > >
> > > Short clips for anyone interested:
> > > http://www.youtube.com/watch?v=X1MkdixNLcc - inside motor
> > > http://www.youtube.com/watch?v=n0JCRY8yGV8 - running in bucket
> > > http://www.youtube.com/watch?v=yUfqSSnEh5c - launch
> > > http://www.youtube.com/watch?v=R2f33577ADo - onboard
> > >
> > > (Later examination revealed the gear noise proved to be because the
> > > vertical shaft was pressing down quite hard on the gear at the foot.)
> > >
> > > It has about 2.8 to 1 reduction at the foot. This proved frustrating
> > > with a 2000 RPM motor, as it wouldn't get the prop going fast enough
> > > at full speed to get the boat making much wake, still less up on a
> > > plane.
> > >
> > > For a runabout, it seemed the prop should be going about the same
> > > speed as the motor (if not faster), not reduced. But all the gas
> > > outboards seem to have a considerable reduction at the foot, and
> > > seemingly no way to change it.
> > >
> > > Another person used an induction motor and a variable frequency drive
> > > (in a Johnson 10 or 15 HP?), which they set to 0-120 Hz insead of
> > > 0-60 Hz to get more speed. Of course, that's double as fast as the
> > > motor was designed to run.
> > >
> > > My latest idea has been to make an outboard from scratch, using two
> > > socket set drive or similar U-joints at the foot (running in oil) to
> > > do the 90 degree bend, 45 degrees each, with (obviously) a 1 to 1
> > > ratio. I still think this should work well - it seems to turn with
> > > low friction by hand (assuming the shafts are fixed in the desired
> > > positions with bearings, not flopping around) - but I've been onto
> > > other projects all summer. (So many things, so little time!)
> > >
> > > =====
> > >
> > > Since I'm writing... I did make or am making some 12 volt things that
> > > might be interesting to some electric boat users:
> > >
> > > - a 12 volt, 5 cubic foot, superinsulated (3" foam), Peltier cooled,
> > > shallow chest fridge, which freezes ice during the day while the
> > > solar energy is there, then lets the ice melt to keep the fridge cold
> > > overnight without needing any battery storage.
> > > - A 3D plastic printer (RepRap Mendel) from a kit. This helps produce
> > > some more things:
> > > - A new standard 12 volt plug and socket: Connector based on AT fuses
> > > (CAT plugs). They're the same as ATO/ATC DC fuses except one pin, the
> > > negative, is turned sideways to ensure polarity. So far I have plugs
> > > for cords, and sockets: for cords, a duplex panel mount face, and a
> > > duplex face for "1110 electrical box" (the ones for house lights and
> > > plugs).
> > > - I plan to wire my house with 12 VDC, with these sockets and plugs.
> > > The power will come from solar collectors now on my roof (charging
> > > NiMH batteries) when available, or from a 12 volt battery charger if
> > > the batteries get too low. I'm designing a 12 volt solar main
> > > distribution box with a number of features and circuits as well as
> > > main and branch breakers.
> > > - I've been doing LED 6" plastic globe lights that are 75 or 100
> > > lumens per watt (where "120 VAC LED bulbs" are usually 67 or less).
> > > I'm just now doing circuits to make lights that can accept
> > > unregulated battery voltage instead of 12.0 volts only. The present
> > > circuit still dims somewhat with falling voltage... which at least
> > > helps conserve low batteries.
> > >
> > > Craig
> > > Victoria BC
> > >
> > > =====
> > >
> > > >Hi,
> > > >
> > > >I am hoping to convert a gas outboard to electric and was wondering
> > > >which gas outboards might be better to start with.
> > > >
> > > >One thing I would particularly like is as low as possible (high
> > > >numerical reduction) of a gear ratio so the prop turns slower.
> > > >
> > > >Does anyone know what the standard gear ratios of common small
> > > >outboards are? Is there possibly a list that I might be able to see?
> > > >
> > > >Thanks!
> > > >
> > > >Bruce
> > >
> >
> >
> >
>
>
>
> --
>
> Joe Grez, President of PropEle Electric Boat motors Inc.
> joe@...
> 425-241-9241
> 10404 428 Ave SE, North Bend Wa, 98045
>
> http://www.linkedin.com/in/joegrez
> www.electricpaddle.com
>
| Reply via web post | Reply to sender | Reply to group | Start a New Topic | Messages in this topic (13) |
No comments:
Post a Comment