[NSRCA-discussion] Looking For Props & Header

[Dave]

A couple additions to the prior post - 

 

Some of the original molds have been modified (based on new theoretical data
or field testing), and this generally happens when the original inventory is
depleted.  The changes in the molds are concurrent to changes in the
algorithms utilized to calculate the prop shape and mold shape, and years
ago, this was recognizable by a change in the label on the prop.  The
earliest APC props were series "A1", and then progressed to A2, A3, etc,
with major changes occurring with "B1".  Not surprisingly, competition
oriented guys wouldn't buy a B11 when they heard a B12 existed...this
ultimately resulted in the nomenclature freezing at "C2", but the
improvements in the algorithms used by APC are never ending.

 

The specific letter modifiers after the prop size are for the most part
relative.  The 16.5x12 was the 1st 16.5x12.  The 16.5x13 and 16.5x14 are the
same planform as the 16.5x12, so they do not have an N or W modifier.  The
16.5x12W is W since it is wider than the original 16.5x12.  The 16.5x13W is
W because it is the same planform as the 16.5x12W.  The original 18x8,
18x10, and 18x12 props have very high taper ratios and massive hubs (used
early on in smaller IMAC style planes).  "PN" is pattern narrow to
differentiate from the IMAC style props, and "WPN" is wide pattern narrow.
The 18.1 series of props are 18.1 to distinguish from the prior series of
18" props. 

 

Regards,

 

Dave 

 

  _____  

From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Troy Newman
Sent: Wednesday, November 04, 2009 12:36 AM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] Looking For Props & Header

 

I don't believe there is such a prop made as the 18.1-11 Narrow. It doesn't
exist. I may be wrong but I have been involved with running and testing the
APC props in the 18.1 series and WPN series.  There is a prop that is
designated as just 18-11 and this has a narrower blade than the 18.1-11.
The 18.1 series of props have a very wide blade. The 18-11 is more like a
17-13 or 17-12 in terms of blade shape but its 18in dia and 11 pitch.

 

I know there is a 16.5-12 I just pulled one out in my box-o-props and it has
a profile like a narrow prop very similar to the 17-10N.however it doesn't
have the designation as 16.5-12 narrow. It's just called the 16.5-12. If you
handed it to me with the name scratched off and said it was a 16.5-12 I
would have said it was a Narrow.  Same goes for the 18-11 regular it's a
narrow essentially as well.

 

I don't know for sure why the "W" designation or the "N" for narrow is left
off of some props and added to others. I think it has a lot to do with the
equations and program that is used to create the prop profile. 

 

To sum up the props APC has the prop if it is or has been produced.  I don't
think Fred throws any of the molds away. So if a prop was produced at one
time it might be possible with some convincing to get some of them produced
again. I have been to the factory where the props are produced. It amazing
how they are produced, and the quantity and quality of props produced for a
given size.

 

You may not be asking for it by the proper name/designation..the 16.5-12 (is
actually like a narrow) and the 18-11 is like a narrow version of the
18.1-11

 

As for Headers...the new header is in testing and is performing well. The
jury is still out, we are working hard to insure the bugs are worked out.
Right things are going well and real progress has been made in the last
couple months. It will be sooner rather than later from the looks of things
on the new headers.

 

I hope this helps answer the questions

 

 

Troy Newman

 

From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of
rjo626 at aol.com
Sent: Tuesday, November 03, 2009 8:20 PM
To: nsrca-discussion at lists.nsrca.org
Subject: [NSRCA-discussion] Looking For Props & Header

 

     Hello all! I'm looking for APC 18.1x11 narrow, and 16.5x12 narrow.
Also,

anyone have a good NMP pattern header they're willing to part with / sell?
I've 

tried Central Hobbies and APC with no luck. Thanks a bunch!

 

     Later!

            RJO

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