From: Ernest Christley <echristley@att.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Tuesday, December 20, 2011 12:16 PM
Subject: [FlyRotary] Re: off topic, propeller carving and paint

Short answer:
1.7m diameter, with a 3.33m pitch.  I'm using a 3.17 reduction gearset, with an "optimistic" output of 199Hp from the
engine, and I was aiming for an aggressive cruise prop under the assumption that cutting off pieces is much easier than
stapling them on 8*)

Long answer:
Look up JavaProp at http://www.mh-aerotools.de/airfoils/javaprop.htm
You can download the app from his page, or just run it from the web.  Enter the following:
2-blade
1730 RPM
1.7m diameter
0.16m spinner
75m/s velocity
141000 W of power
square tip

In the airfoils tab:
MH126 at 6*
MH112 at 2*
MH114 at 2.5*
E193 at 3.5*

Go back to the Design tab and click "Design It!" at the bottom.  On the Multi-Analysis tab, click "Analyze!" at the
bottom.  More numbers than a person knows what to do with.

I am not delusional enough to think that this first example will be a perfect match.  It will hopefully get me some good
data on the upper limit of what my engine/airframe combination will handle; but, more than that, it is meant for me to
iron out the construction process.

The core is southern white pine (cheap, light, soft, and carves nicely), with a heavy layer of glass to carry the loads.
Over the course of making this one, I've learned how to organize the milling to minimize the amount of cutting
necessary, and how to get the cutter down a 6" hole.  I had to switch the cutting head from a laminate router, to an
electric die grinder.  To rough it in, I was originally cutting a grid at 1" intervals and then chiseling away the
"non-propeller" chunks.  I'm now just cutting cross-wise slots at 6" intervals and chiseling off the excess.  Makes a
BIG difference when you're cutting head movement is limited to about 5"/min.


Tracy wrote:
> Only a glimpse of the full blade but it looked like one hell of a high
> pitch on that thing.  What are the figures on it?
>
> Tracy
>
> On Mon, Dec 19, 2011 at 3:18 PM, Ernest Christley <echristley@att.net
> <mailto:echristley@att.net>> wrote:
>
>    Ed Anderson wrote:
>    > Impressive, Ernest, so when do you start producing Props for the list?
>    >
>    > Ed
>
>    Started already.  Did you see how slowly that cutting head was
>    moving?  I don't think most of us here will be alive by
>    the time I'm ready to ship in quantity 8*)
>
>    >
>    > --------------------------------------------------
>    > From: <echristley@nc.rr.com <mailto:echristley@nc.rr.com>>
>    > Sent: Monday, December 19, 2011 11:18 AM
>    > To: "Rotary motors in aircraft" <flyrotary@lancaironline.net
>    <mailto:flyrotary@lancaironline.net>>
>    > Subject: [FlyRotary] off topic, propeller carving and paint
>    >
>    >> Thought you guys might be interested in the video of how my propeller
>    >> carving is going:
>    >>
>    >> http://www.youtube.com/watch?v=YzViR2agLcY
>    >>