[NSRCA-discussion] APC 18.1 x 10W props

Wed Nov 15 15:04:21 AKST 2006

The GPS system doesn't like vertical lines and inverted flight.  The normal altitude and speed sensors work much better.  Definitely should be on everyone's wish list, especially flying electric.

Jim O
  ----- Original Message ----- 
  From: Bob Richards 
  To: NSRCA Mailing List 
  Sent: Wednesday, November 15, 2006 1:35 PM
  Subject: Re: [NSRCA-discussion] APC 18.1 x 10W props

  Earl,

  I see they also have a GPS option. It would be real interesting to compute velocity relative to the ground. This would be a good indication of how to alter throttle management in wind situations.

  Now I know "track" is the only thing that should be judged, but a constant velocity makes it easier to present good geometry to the judges. JMHO.

  Bob R.

  Earl Haury <ehaury at houston.rr.com> wrote:
    Bob

    I've used the datalogger as you describe for prop evaluations. The data will provide some surprises. I also gather data throughout a pattern sequence then note those data (airspeed / altitude) onto an Aresti of the pattern - very useful in fine tuning geometry / throttle use / braking. Move the thing to the top of your wish list!

    Earl
      ----- 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: 
          Peter,
          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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