Jantar SZD 48 "Jantar Std 2" - wing profile templates

[Phil Stade]

I am looking for wing profile data for the Jantar SZD 48 Std 2. Anyone have that information?
Thanks
Phil

[Phil Stade]

Our Jantar is Serial W-856 built in 1984. The Flight Manual from Jantar Serial B-1049 says that the wing profile is NN8. Some sources indicate a Wortmann profile. Is there another way of determining the profile used on W-856?
Thanks
Phil

[Bob Kuykendall]

On Thursday, November 23, 2017 at 9:33:39 PM UTC-8, Phil Stade wrote:
> Is there another way of determining the profile used on W-856?

I've collected profiles from half a dozen airplanes and gliders, and in general there seems to be only a passing resemblance between what is manufactured and its published coordinate sets. Of course, it is much better these days with the increasing use of very stable CNC-cut molds. But even as recently as the mid 1990s you could find new gliders with very marked differences not only between published and actual coordinates, but even between right and left wings.

If you really want to know what's there, your best bet is to extract your own coordinate set. One such method is described in my 2006 Update called Steal This Airfoil:

http://www.hpaircraft.net/hp-24/update_8_december_06.htm

Thanks, Bob K.

[chip.b...@gmail.com]

Bob,

Define "straight and square". Most wings have leading edges that are swept back and/or trailing edges that are swept forward. In fact, unless it's a constant chord wing (a la the old HP-10), the leading and trailing edges aren't parallel. And neither one may be perpendicular to axis of the fuselage (i.e., direction of flight). So how to align the foam core board on which you trace the airfoil?

I guess if all you're doing is creating templates to use during refinishing, it doesn't matter how you align it so long as you can duplicate the same alignment after the old gel coat is stripped off and new gel coat is applied. In that case, aligning the "chord" perpendicular to the leading edge probably works fine. But is that true if you're really trying to pull coordinates?

Chip Bearden

[Bob Kuykendall]

On Tuesday, November 28, 2017 at 10:31:04 AM UTC-8, chip.b...@gmail.com wrote:
> Bob,
>
> Define "straight and square". Most wings have leading edges
> that are swept back and/or trailing edges that are swept forward.

Parallel with the fuselage longitudinal axis, orthogonal to the plane containing the leading and trailing edges. In the absence of sweep reference, splitting the difference between the leading and trailing edges will get you plenty close enough. Which is to say, closer than the difference between the right and left wings on your glider.

--Bob K.

[Mike C]

A few years ago Robert Mudd and I had CNC templates made for a PIK 20B according to the airfoils used and blended from root to tip. I do not think there was one station that had the correct airfoil shape and one wing did not agree with the other as far as deviations that were fairly large.

Mike

[Dan Marotta]

Mike,

Were the flying qualities and performance noticeably improved after
profiling the wings?

--
Dan, 5J

[Mike C]

No idea it was a project that remains unfinished in it's trailer.

Mike

[Piotr Szafranski]

It is called NN-8. Cl(alpha) can be found in
INFLUENCE OF MINIFLAPS ON SAILPLANE FLIGHT CHARACTERISTICS
Peep LAUK1, Karl-Eerik UNT

AVIATION
ISSN 1648-7788 / eISSN 1822-41802015 Volume 19(3): doi:10.3846/16487788.2015.1104793

pages 105–111 Fig.12.

https://www.researchgate.net/publication/283838508_Influence_of_miniflaps_on_sailplane_flight_characteristics/fulltext/5ba7d6afa6fdccd3cb6d55ef/Influence-of-miniflaps-on-sailplane-flight-characteristics.pdf