Apr 25, 2012, 11:22 PM deltas are cool Tehachapi ,CA. Joined Apr 2006 23,921 Posts we used french curves to draw them ,it is a semi symetrical foil and fairly thin for the size of wing .....thick enough to get the gear in . have been drawing our own foils for years ...so far we have'nt missed yet ,C/N has done 2 other F-5's so he know about what is needed .....but we might not be able to tell you why we did it that way ...neither of us have a eng. degree....thats why we just work on full scale planes...but i did sleep in my own bed last night if anything it looks like a eppler foil.....guessing some where between 7%-9% thickness.@ 3 degrees of washout .
 Apr 26, 2012, 04:40 AM Registered User McQueeney TX Joined Oct 2005 612 Posts OK, I noticed some secrecy here, I couldn't get Nut to cut me a set or share the templates so I could build a plane with this wing. That's cool, it's probably not that critical, like you say, just enough to get the gear in. I don't think you could "miss" with a jet, I bet this thing would fly with a flap piece of foam.
 Apr 26, 2012, 08:28 AM Retired and Lovin' it! United States, KY, Sturgis Joined Jul 2007 2,809 Posts Dionysus, I can't speak for CN or Air Sally here but I have been doing my own airfoils for years using the same methods that AS just described. I draw a straight line to the length of the chord, then draw another straight line vertical at about 30% of the chord line. The length of the vertical line is determined by the percentage of thickness of the wing, i.e., if the chord is 12 inches, with 10% thickness, then the vertical line is 1.2 inches in length. If the foil is symmetrical, then .6 above the chord line and .6 below. If semi-symmetrical, then you choose what looks about right for you. I set the leading edge radius with a TLAR calibrated eyeball keeping in mind that a sharper leading edge will tend have a sharper stall break. Then connect all points with French curves and straight edges. You'ld be amazed how well this works. No secrets! Tony
Apr 26, 2012, 08:46 AM
Registered User
McQueeney TX
Joined Oct 2005
612 Posts
Thanks Tony.

I'm going to use Profili 2, it makes it easy. I'm going to use the NACA 64-008A.

Just for reference the T-38, F-20 and F-5 use the root = NACA 65A004.8 and tip = NACA 65A004.8

Found some stuff in my T-38 searches.

# Images

 Apr 26, 2012, 11:11 AM Retired and Lovin' it! United States, KY, Sturgis Joined Jul 2007 2,809 Posts Profili works great too. I am not proficient in CAD so I hand draw my plans. Its more of a pain to copy and print Profile outlines and then transfer to my hand drawn plans. Tony
 Apr 26, 2012, 12:38 PM deltas are cool Tehachapi ,CA. Joined Apr 2006 23,921 Posts what?! C/N wont give you a wing template ???? he must have lost it ,there was nothing secret about it i bet he'd make a set of cores for a F-86 cockpit personally i think we should make a semi kit for this plane
 Apr 26, 2012, 02:09 PM fly like an EAGLE ;) tehachapi, CA Joined Jan 2006 26,426 Posts i never said i wouldnt give him the airfoils, not sure where he got that. i sent him a pm.
 Apr 26, 2012, 06:28 PM EDF Jet Jam 2016, June 16-19 St. Louis Intl, Missouri, United States Joined Jan 1997 7,201 Posts I'm sure that CN is among many others that just manipulate existing airfoils to serve their needs. I am guilty of this myself...when someone ask, it is a modified Clark Y.
 Apr 27, 2012, 09:31 AM Onward and upward. United States, CO, Delta Joined Oct 2006 2,198 Posts Eddie, with these relatively large jet models, wouldn't reynolds numbers come into play? Thanks, Randy
 Apr 27, 2012, 09:52 AM Build'em and Crash'em Narragansett, RI Joined Oct 2000 3,907 Posts Understand of course that the airfoil you started with on the template may not be the airfoil you end up with after glassing, sanding and painting
Apr 27, 2012, 10:48 AM
Official Boat Bum
United States, NV, Reno
Joined Mar 2000
8,766 Posts
Quote:
 Originally Posted by Pilatuspc12 Eddie, with these relatively large jet models, wouldn't reynolds numbers come into play? Thanks, Randy
Yes but I also included an example of an RC airplane to balance it out It's still fluid dynamics even at the low RN of model airplanes. Not as critical but still the physics apply IMHO enough that guys like CN are not wasting their time when they try to add a natural flowing shape to the wing with a french curve even on their own designs. When I was going to college we had a subsonic wind tunnel and a supersonic wind tunnel. We were using model airplane size sections and they certainly made a difference in the wind tunnel among different sections, and that was the point of the whole testing apparatus, to test different airfoils. The small sizes were still bound to natural laws. Anyhow, I do concede that at our lighter wing loadings we can certainly get away with a lot but if someone were to say airfoils don't make a difference in models I'd say they were painting with a pretty broad, generalized and messy brush IMHO.
 Apr 27, 2012, 09:02 PM Oh wow, good Nyborg. Austin, Texas Joined Dec 2005 309 Posts I agree with Eddie P. For the most part... When you are talking about powered models in the lower Reynolds numbers range. If you mount a telemetry device and flew untold hours, allowing for all the atmospheric variables, you would see a difference. But when using the calibrated eyeball ground observation method... Go to the "serious sailplane forums", not the clueless foamy crowd, and read the discussions on airfoil selection. There is a huge difference when you do not have a fan pushing you around. Peace, Wolf
 Apr 30, 2012, 11:58 AM Member 120mph Club New Bern, North Carolina, United States Joined Oct 2004 12,474 Posts I just want to thank Falcon 5 for taking care of my F9 at SEFF. He flew the crap out of her and made her look good.
Apr 30, 2012, 12:01 PM
Oh wow, good Nyborg.
Austin, Texas
Joined Dec 2005
309 Posts
Quote:
 Originally Posted by ATIS I just want to thank Falcon 5 for taking care of my F9 at SEFF. He flew the crap out of her and made her look good.
Videos or didn't happen... LOL

Wolf