[NSRCA-discussion] APC 18.1 x 10W props

Wed Nov 15 12:45:25 AKST 2006

Jim
How was the fuel consumption with the DL prop?
I saw a marked increase with the standard 15.5x12 apc.
I stretched the Throttle curve in the midrange to tone down the power acceleration,with my 18.1x10W.  I am considering lowering the top end rpm and spreading out the stick sensitivity.
This will work except for windy days then I go back to normal throttle.

Jim Ivey
  ----- Original Message ----- 
  From: Jim Woodward 
  To: 'NSRCA Mailing List' 
  Sent: Wednesday, November 15, 2006 2:02 PM
  Subject: Re: [NSRCA-discussion] APC 18.1 x 10W props

  Mike - Glad to see you on the list.  

  With the 18.1x10.1 and YS 160 launching around 8100, the speed changes of the plane nearly follow the throttle stick movement.  At full tilt, the plan can still accelerate away from you, however, at ¼, 1/3, 1/2, ¾ stick positions, the plane changes speed as you move the stick.  Very nice.  I tried the DL 15.75x10 3 blade this weekend on the YS 160.  This prop is very quiet, the overall speed was a tad less than the 18.1x10.1., At the top end, it did not accelerate away from you, and overall, it was a bit easier to shape the pattern.  Plane speed definitely changes with stick position.  With the 18.1 I find myself changing power settings on uplines and such - requires quite a bit of throttle stick work to not "explode" through maneuvers.  With the 3 Blade, it was easier to hit a consistent pace.  

  3 Blade enough power?  I went through F07 too with it had more than enough power to handle the Rolling S, top hat with ¾ point up,  4-point up.  This prop is right in the sweet spot of the YS 160.  I did not tach this prop.  It was about 85 degrees in Miami.

  Jim W.

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  From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of george w. kennie
  Sent: Wednesday, November 15, 2006 1:03 PM
  To: NSRCA Mailing List
  Subject: Re: [NSRCA-discussion] APC 18.1 x 10W props

  Welcome to the list Mike!!!!!

    ----- Original Message ----- 

    From: Dr. Mike Harrison 

    To: NSRCA Mailing List 

    Sent: Wednesday, November 15, 2006 8:31 AM

    Subject: Re: [NSRCA-discussion] APC 18.1 x 10W props

    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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