[Towertalk] Prop-Pitch
GALE STEWARD
k3nd@yahoo.com
Mon, 3 Jun 2002 05:06:59 -0700 (PDT)
My PP is mounted to a modified Rohn rotator mounting
plate. I took it to a machine shop and had them cut a
larger center hole in it. Think it 5 or 6 inch
diameter. You DO need the bevel gear to make any type
of coupling to the mast. I used an output shaft and
clamp assembly from a trashed Hygain RotoBrake 400.
I need to get up my tower with the digital camera then
I could post some pix.
73, Stew K3ND
--- dan hearn <dhearn@ix.netcom.com> wrote:
> Hi Greg: You are correct, they are mounted to a
> plate with a hole in it
> large enough to let the output shaft pass thru it.
> The unit shown in the
> ebay add is missing a large bevel gear which mounts
> to the splined
> output shaft. Most people weld a bushing to the
> bevel gear for attaching
> the tubular mast and the bevel gear takes the
> vertical load. It is
> possible to use the splined shaft for output by
> machining a mating
> bushing.
> You do need a direction indicator. If the bevel
> gear is on the unit,
> some people make a large gear out of sheet metal the
> same diameter which
> will mesh with it to rotate a potentiometer or
> selsyn. Some of the PP
> mod articles have dimensions so you can make it with
> a drill and a file.
> I have used sprocket and chain drive as well as a
> small dial cable and
> pulley arrangement to turn a potentiometer.
> It is essential that the top of the unit and the
> indicator you use be
> protected from weather. I have seen PP motors in
> flea markets which were
> not protected and the bevel gear and the ball
> bearings beneath it are
> rusted.
> M2 sells a modified version of their OR 2800
> control and indicator box
> for PP motors. You attach a small magnetic pickup to
> the motor shaft
> which generates pulses as you rotate and the unit
> supplies power for the
> motor.. The price is around $500 I believe.
>
> 73, Dan, N5AR
>
> Greg Gobleman wrote:
> >
> > I was looking at the photos of this prop pitch,
> not having seen one mounted
> > I was trying to figure out how they are installed.
> I assume the flat plate
> > area is bolted to a stationary plate. Is a
> notched piece made to adapt to
> > the mast pipe? I also have read of needing to rig
> a directional indicator
> > of some kind. Any info on that? May I assume
> that the control box and
> > indicator will probably cost as much as the rotor?
> >
> > 73
> > Greg K9ZM
> >
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