[NSRCA-discussion] Trailing Edge

[Dean Pappas]

Hey Matt,
What George was saying pretty much boiled down to: 
1) you can build a killer L/D wing with a super sharp composite trailing edge. 
2) you can build pretty much just as good an airfoil intended for thick wooden trailing edges. 
And,
The two airfoils will be substantially different. ( What Nat mentions with TE fineness)
They are notoriously unforgiving of building or shape errors.
The "good" thick TE foils are more forgiving of building errors.
and finally ...
No present day student involved in the program wants to build a low-tech wooden wing!
This made George laugh and then we went on to discuss the whole stability versus ultimate performance tradeoff.
 
later,
Dean

	-----Original Message----- 
	From: nsrca-discussion-bounces at lists.nsrca.org on behalf of rcmaster199 at aol.com 
	Sent: Tue 2/13/2007 6:04 PM 
	To: nsrca-discussion at lists.nsrca.org 
	Cc: 
	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 <mailto:d.pappas at kodeos.com>  
			To: NSRCA Mailing List <mailto:nsrca-discussion at lists.nsrca.org>  
			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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