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<DIV>Matt, you are correct. Feel free to help clarify my
comments.
Nat</DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=Rcmaster199@aol.com
href="mailto:Rcmaster199@aol.com">Rcmaster199@aol.com</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Saturday, October 16, 2004 12:02
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Propeller Pitch gauge
calibration</DIV>
<DIV><BR></DIV><FONT id=role_document face=Arial color=#000000 size=2>
<DIV>
<DIV>Nat, taking a hypothetical example of a 20x10 prop, the radius is 10
inches and coincidentally so is the pitch at the 70% station of the prop.
</DIV>
<DIV>The 70% point is 7" from center. </DIV>
<DIV>The circumference of the circle at that station is 2x(7")x Pi. </DIV>
<DIV>The right triangle would then have a base of 2R x Pi and a height of
10"(prop pitch). </DIV>
<DIV>The hypotenuse inscribes angle which is the true pitch angle at the 70%
station. </DIV>
<DIV>(Reducing the triangle down to say 5% of the original makes it
manageable.)</DIV>
<DIV>Is this what you mean?</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>Matt</DIV>
<DIV> </DIV>
<DIV> </DIV>
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<DIV><FONT face=Arial size=2>Peter,</FONT></DIV>
<DIV><FONT face=Arial size=2>Prop pitch is measured at the 70% station.Pitch
distribution along the span ( deviation from true pitch ) is proprietary and
is, in the case of APC, what accounts for their excellent performance and
low noise.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>A way to calibrate your gauge is to make a
template , a triangle with the x axis equal to the circumference at a
given blade station and a slope of ,say, 10 inches and check this
against the guage reading at that station.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>i.e. at each station a prop will "twist"
forward the same amount in one revolution if it has true pitch ( no slippage
).</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>You do not need to express inches of pitch as
degrees.</FONT></DIV>
<DIV><FONT face=Arial size=2>When are you going to give me a report on the
Alliance trim !!</FONT></DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=mailto:pentagon.systems@bigpond.com
href="mailto:pentagon.systems@bigpond.com">Peter Pennisi</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=mailto:discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, October 15, 2004 5:18
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Propeller Pitch gauge
calibration</DIV>
<DIV><BR></DIV>
<DIV class=Section1>
<DIV>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Hi
Guys,<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">I have modified a
propeller pitch gauge to accommodate larger propellers. The gauge I have
is a very old prop shop model.<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">I have decided to
check my APC props because I was getting mixed performance results between
all my prop sizes.<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Anyway I thought
I would check my gauge with a new prop to see how accurate it was and the
numbers I got were different to what was on the prop. I tried another new
prop of exactly the same size I got a different result again. Anyway I am
shocked to find that what is displayed on the prop is different to my
measurements.<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">What part of the
prop should I be measuring my pitch as this varies slightly over the
length of the blade?<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">Secondly, how
would I go about calibrating my unit because I can’t do it with new props
because there all different.<o:p></o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial"><o:p> </o:p></SPAN></FONT></P>
<P class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">How do I express
for example 13 inches of pitch as
degrees?</SPAN></FONT></P></DIV></DIV></BLOCKQUOTE></FONT></BLOCKQUOTE></DIV>
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