[NSRCA-discussion] APC 18.1 x 10W props

Wed Nov 15 12:46:25 AKST 2006

Nat,

  I've played a lot with the small electrics (4S packs up to 2500mah) and have come to realize it is very easy to pick props for performance. The torque/power curve is very linear and predictable for electric motors, and does not change with climate. 

  This is not the case with IC, the torque/power curve is another HUGE variable and also changes with climate.

  Bob R.

Nat Penton <natpenton at centurytel.net> wrote:
      Bob
  There was a recent article in Kitplanes detailing what Hartzell goes thru to get a prop certified for a given engine. They even talk about failure modes you can't feel in the cockpit.

  It's no wonder were always hun'tin for our IC engines. Electrics have far fewer problems.             Nat
    ----- Original Message ----- 
  From: Bob Richards 
  To: NSRCA Mailing List 
  Sent: Wednesday, November 15, 2006 10:26 AM
  Subject: Re: [NSRCA-discussion] APC 18.1 x 10W props

  I'm curious about how one comes up with the best prop selection. In my case, it has always been a very subjective thing to determine the in-flight performance.

  Has anyone used any of the dataloggers to measure airspeed on up/down/level lines? IMHO, that would be one way to remove some of the subjectivity of in-flight performance. I think one of my christmas wish-list items is the Eagle Tree system.

  Bob R.

mike mueller <mups1953 at yahoo.com> wrote:
   From my experience this is the best prop I have tried to date. I have mine on a YS160/Genesis. I was using Biela 3 bladed props,APC 4 bladed props and the 18x10.1 regular APC and this gives the best performance so far. Mike Mueller 

"Dr. Mike Harrison" <drmikedds at sbcglobal.net> wrote:       @font-face {   font-family: Palatino Linotype;  }  @font-face {   font-family: Comic Sans MS;  }  @page Section1 {size: 612.0pt 792.0pt; margin: 36.0pt 77.95pt 36.0pt 77.95pt; }  st1\:* {   BEHAVIOR: url(#default#ieooui)  }  P.MsoNormal {   FONT-SIZE: 12pt; MARGIN: 0cm 0cm 0pt; FONT-FAMILY: "Palatino Linotype"  }  LI.MsoNormal {   FONT-SIZE: 12pt; MARGIN: 0cm 0cm 0pt; FONT-FAMILY: "Palatino Linotype"  }  DIV.MsoNormal {   FONT-SIZE: 12pt; MARGIN: 0cm 0cm 0pt; FONT-FAMILY: "Palatino   Linotype"  }  A:link {   COLOR: blue; TEXT-DECORATION: underline  }  SPAN.MsoHyperlink {   COLOR: blue; TEXT-DECORATION: underline  }  A:visited {   COLOR: purple; TEXT-DECORATION: underline  }  SPAN.MsoHyperlinkFollowed {   COLOR: purple; TEXT-DECORATION: underline  }  P.MsoPlainText {   FONT-SIZE: 10pt; MARGIN: 0cm 0cm 0pt; FONT-FAMILY: "Courier New"  }  LI.MsoPlainText {   FONT-SIZE: 10pt; MARGIN: 0cm 0cm 0pt; FONT-FAMILY: "Courier
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  Hi,
  I am Mike Harrison, I worked with APC to develop these props.  Let me tell you the goal of the prop design.  It is to fly at a moderate to slow constant speed under the noise limit but with good pulling performance.  Therefore, regarding the rpm, the 8000 is about ideal for that prop, turn it much more and you will be above the noise limit.  

  I find it interesting that you determine whether a prop is adequate by first tacking it.  I would think you would fly it first to see if it was adequate.  I would encourage you to do that first.  The OS 140 turns it about the same and it flies very well. 

  The whole purpose was to develop a prop that would fly at a deliberate pace at about 150 meters to compete with the electrics.  

  There is also an 18.5x9.5 which I fly and it turns about 7500 rpm.  I like it better than the 18.1x10.  I am working on a 19x9 at the moment.

  Good luck
  Mike
    From: Peter Pennisi 
  To: 'NSRCA Mailing List' 
  Sent: Tuesday, November 14, 2006 5:48 PM
  Subject: [NSRCA-discussion] APC 18.1 x 10W props

  I recently purchased some 18.1 x 10W APC props for my DZ160. Apparently there appears to be another version 18.1 x 10.1.

  Could someone please tell me the difference between both?

  I tried a quick ground run on this prop (stock) this morning but could barely get 8000 RPM from the engine. I will take advice from a member on this list and lop 1/4inch of each blade. What RPM readings are people getting who are using either of these props on a YS DZ160 engine?

  Regards,

  Peter 

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