[NSRCA-discussion] Trailing Edge

[Fred Huber]

prop noise.

You can hear the difference in an APC prop if you sand the TE to get rid of the knife edge.  They are using the sharp TE and thin airfoil.

Easy to confirm:  Get a wattmeter and an electric drive.  Turn the APC prop appropriate for the motor and do a sound check... then sand the TE (such as is commonly done by some people...)  check sound and power demanded by the motor again.
  ----- Original Message ----- 
  From: Bob Richards 
  To: NSRCA Mailing List 
  Sent: Tuesday, February 13, 2007 10:29 PM
  Subject: Re: [NSRCA-discussion] Trailing Edge


  Ok, why don't we chop off the trailing edge of our props?

  Bob R.


  Nat Penton <natpenton at centurytel.net> wrote:
    Dean
    The old NACA must have done this research in the distant past. I recall, in the 80s, Jim Bede extolling on the virtues. 

     The Princeton project, that would be fun, especially as a student. Would have kept my attention <G>.              Nat
      ----- Original Message ----- 
      From: Dean Pappas 
      To: NSRCA Mailing List 
      Sent: Tuesday, February 13, 2007 10:03 AM
      Subject: Re: [NSRCA-discussion] Trailing Edge


      Thanks Nat,
      I have a guy in the local club who corroborates Barnaby's statement. Locally to NSRCA D1, back in the 80's he was known as "forever in Sportsman George".
      He is recently retired from teaching at the Aero group at Princeton U. and he still coaches the students involved in the weight lifting contest.
      It was nice to have an excuse to go hunt him down!

      later,
      Dean

      Dean Pappas 
      Sr. Design Engineer 
      Kodeos Communications 
      111 Corporate Blvd. 
      South Plainfield, N.J. 07080 
      (908) 222-7817 phone 
      (908) 222-2392 fax 
      d.pappas at kodeos.com 
        -----Original Message-----
        From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of Nat Penton
        Sent: Tuesday, February 13, 2007 1:05 AM
        To: NSRCA Mailing List
        Subject: [NSRCA-discussion] Trailing Edge


        Kitplanes, Dec 06           Wind Tunnel by Barnaby Wainfan

        " The airfoil with the chopped trailing edge will produce slightly more lift at the same angle of attack than a sharp trailing-edged airfoil. Because the wake is filled in the controll is crisper and more effective and does not have to move as far to cause a change in lift"

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