[NSRCA-discussion] Trailing Edge

[Nat Penton]

Matt
I condensed the Kitplanes article from 2 1/2 pages. Lowest drag occurs with a sharp TE and a very small angle between the top and bottom flow. With typical sections a sharp TE moves the separation point upstream, away from the TE, with a corresponding increase in drag and poorer, maybe unstable, controll response.

I suppose, with a sailplane, you would want the " cuspy" looking section.
  ----- Original Message ----- 
  From: rcmaster199 at aol.com 
  To: nsrca-discussion at lists.nsrca.org 
  Sent: Tuesday, February 13, 2007 5:04 PM
  Subject: Re: [NSRCA-discussion] Trailing Edge


  Nat, Dean,

  It seems to me that for the kind of thing we are involved in, the boost in control performance is desired. Drag is not necessarily our enemy...in fact quite the contrary. We've been building fattened TEs on our models' control surfaces and have been deriving the benefits, perhaps unwittingly. It has been useful information and the benefits would appear to outweigh the penalty.

  However, this may not hold true for other flight regimes. If one were to look at the wing TE of a 777 for example.....quite sharp. Ditto for fighters and racers. These are distinct and different regimes than our interest, with a totally different goal in mind....n'est-ce pas? 

  On the other hand, sailplanes would probably also benefit and here there appears to be a mixed bag of thicknesses.

  I guess the point is "it depends"

  Matt

   
  -----Original Message-----
  From: d.pappas at kodeos.com
  To: nsrca-discussion at lists.nsrca.org
  Sent: Tue, 13 Feb 2007 1:25 PM
  Subject: Re: [NSRCA-discussion] Trailing Edge


  Hi Nat,
  So the Princeton Aero department had many of its facilities just a couple of miles up US Route 1 from the College, at Princeton-Forrestal airport.
  It is owned by the University. The land is gradually being gobbled up by industrial developments and the runway is gone now. Bummer 'cause we used to hold a Pattern contest there years ago. 

  The SAE weight lifting contest is still a going concern. It sure is neat ... why wasn't this sort of thing around when I was in Engineering School?

  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 11:29 AM
    To: NSRCA Mailing List
    Subject: Re: [NSRCA-discussion] Trailing Edge


    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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