LS3A Wing Profile Data

[Robert Fidler]

Will be refinishing and profiling a LS3A this winter. Need the wing profile
data which manufacture will not share.
Does anyone out there have tha data they would be willing to share with
me?

email

Bob Fidler

[KevinFinke]

This site, compiled by Dave Lednicer, lists the LS-3 as using the
Wortmann "FX 67-K-170" at the root and a "FX 67-K-150 mod" at the tip.

http://www.ae.uiuc.edu/m-selig/ads/aircraft.html

This agrees with the data in the Thomas book as well as the
directories by Martin Simmons. It was a very popular airfoil on a lot
of gliders from that era.

If you go to this site, you'll find a data file that lists the
coordinates in non-dimensional values.

http://www.ae.uiuc.edu/m-selig/ads/coord_database.html

Now the tricky part....

It may or may not be 17% thick at the root, and typically the airfoils
were scaled in thickness to allow for more uniform spar height
tapering. As a result, you'll probably need to measure the thickness
vs chord ratio at a number of stations and scale appropriately to
match. Also, the tip airfoil is different, and who knows where the
designer started to "blend" into this airfoil along the span...

Now the cool part...and I'm sure I'll get flamed from people who
disagree.... Can't wait.... :)

It really doesn't matter that you get the shape just right for the
full length of the airfoil. The underlying structure is by itself
fairly accurate. You're not going to be sanding away fiberglass. What
does matter is that the profile itself is relatively free of waves and
that the underlying surface quality is quite smooth. Waviness will do
more damage than a slightly in-accurate profile. Hence, you could get
by with just stripping down the gel-coat to the glass, spraying up a
nice uniform thickness of new gel-coat and then spending all of your
time getting rid of chord wise waves. Once that is done, polish up the
final result to a mirror smooth surface and you're done. Technically
you don't even have to polish to mirror smooth, 600 grit sand paper
would yield a smooth enough surface, but your gel coat will last a lot
longer if you go higher. No templates necessary.

-Kevin

[[email protected]]

On Oct 21, 6:45*pm, Robert Fidler
> wrote:
> Will be refinishing and profiling a LS3A this winter. Need the wing profile
> data which manufacture will not share.
> Does anyone out there have tha data they would be willing to share with
> me?
>
> email
>
> Bob Fidler

Careful about free advice! It ain't just about waves.
The 67 series is very sensitive to correct profile on the leading
edge.
A few measurements should show linear taper root to tip with airfoil
doing the same thing.
The bad news is that to make templates , you have to plot the airfoil
at each station interpolating between the 67-170 and 67-150.
You don't really want to know how I know this. It's painful.
Look up the series Dick Johnson wrote on improving the PIK-20 which
uses the same series airfoils.
There is much to learn in these articles.
Good luck
UH

[Bill Daniels]

You know, I've been flying FX 67-150 and -170 airfoils for years. I've
smashed thousands of bugs, flown through many rain showers and even
collected substantial ice on occasion yet I've not seen any unusual
performance degradation when analyzing flights with SeeYou nor did I feel
any in flight. In fact, those glides with crappy wings often show a
height/distance ratio well above the published L/D. I know Bob Faris gets
great results with his LS-3a in the same conditions. I wonder if these
airfoils are getting a bad rap.

There are PC software programs that will interpolate airfoils and generate
intermediate templates. Just save the results as a .dxf file and email it
to a laser cutting shop so they can make a complete set of templates. I've
had them made out of Plexiglass with laser alignment holes. A complete wing
set should cost no more than a couple of hundred bucks.

In fact, if you just like airfoil shapes as wall hangings, your local
plastic/sign shop can burn them on its laser cutter from .dxf files.

> wrote in message
...
On Oct 21, 6:45 pm, Robert Fidler
> wrote:
> Will be refinishing and profiling a LS3A this winter. Need the wing
> profile
> data which manufacture will not share.
> Does anyone out there have tha data they would be willing to share with
> me?
>
> email
>
> Bob Fidler

Careful about free advice! It ain't just about waves.
The 67 series is very sensitive to correct profile on the leading
edge.
A few measurements should show linear taper root to tip with airfoil
doing the same thing.
The bad news is that to make templates , you have to plot the airfoil
at each station interpolating between the 67-170 and 67-150.
You don't really want to know how I know this. It's painful.
Look up the series Dick Johnson wrote on improving the PIK-20 which
uses the same series airfoils.
There is much to learn in these articles.
Good luck
UH

[Michael Huber]

"Bill Daniels" <bildan@comcast-dot-net> wrote

> There are PC software programs that will interpolate airfoils and generate
> intermediate templates. Just save the results as a .dxf file and email it
> to a laser cutting shop

www.profili2.com would be my first choice: inexpensive, powerful and easy
to learn and use. Once you know chord length and t/c ratio of your wing
creating a DXF for the templates takes less than one hour.

IIRC there were different versions of the FX67 leading edge, see
http://www.gliderforum.com/thread-view.asp?threadid=2128 for a start.

Michael

[[email protected]]

On Oct 21, 11:26*pm, "Bill Daniels" <bildan@comcast-dot-net> wrote:
> You know, I've been flying FX 67-150 and -170 airfoils for years. *I've
> smashed thousands of bugs, flown through many rain showers and even
> collected substantial ice on occasion yet I've not seen any unusual
> performance degradation when analyzing flights with SeeYou nor did I feel
> any in flight. *

That's astounding...

I owned an HP-18 for years that made an honest 40:1 clean... and about
7:1 in light rain. I'd feel the ship get draggy with the first tiny
spots on the canopy. In a light rain shower the entire ship hummed
audibly and one had to push the stick forward to maintain 55 kts. The
stall speed went up rather a lot too, but I don't recall any
specifics.

More recently, I watched a Glasflugel (or HPH or whatever they are)
304 -- which has a very similar looking airfoil the root if not
precisely the same airfoil -- get "washed" off a ridge in rain showers
that had little effect on my ASW-20. He might as well have flown into
a net.

I wonder if you have a different leading edge section on your ship, by
happenstance or design. It would be very interesting to discover what
the difference is.

-T8

[JJ Sinclair]

Been-there-done-that and guess what? Only the first 4 inches are
important. I make up templates before starting, every 24 inches and
then keep everything aft of that dead smooth both cord-wise and span-
wise. Quick and dirty templates can be made from cardboard that is cut
close then crammed over a strip of bondo which is gooped over aluminum
foil every 24" with wing leading edge vertical.
Both Dick Johnson and Allen Bickle made up full scale templates,
worked forever and the bird didn't perform any better than advertised,
except it was a lot heavier because of all that bondo!. Bickle's bird
had a trailing edge that was a good 5mm thick, because that's what the
templates dictated.
Save your time and bondo, concentrate on the first 4".
JJ
When I say bondo, I'm talking about Evercoat Rage Gold, good stuff,
works easy and sticks like mad!


wrote:
> On Oct 21, 11:26�pm, "Bill Daniels" <bildan@comcast-dot-net> wrote:
> > You know, I've been flying FX 67-150 and -170 airfoils for years. �I've
> > smashed thousands of bugs, flown through many rain showers and even
> > collected substantial ice on occasion yet I've not seen any unusual
> > performance degradation when analyzing flights with SeeYou nor did I feel
> > any in flight. �
>
> That's astounding...
>
> I owned an HP-18 for years that made an honest 40:1 clean... and about
> 7:1 in light rain. I'd feel the ship get draggy with the first tiny
> spots on the canopy. In a light rain shower the entire ship hummed
> audibly and one had to push the stick forward to maintain 55 kts. The
> stall speed went up rather a lot too, but I don't recall any
> specifics.
>
> More recently, I watched a Glasflugel (or HPH or whatever they are)
> 304 -- which has a very similar looking airfoil the root if not
> precisely the same airfoil -- get "washed" off a ridge in rain showers
> that had little effect on my ASW-20. He might as well have flown into
> a net.
>
> I wonder if you have a different leading edge section on your ship, by
> happenstance or design. It would be very interesting to discover what
> the difference is.
>
> -T8

[Robert Gaines[_2_]]

Some thoughts to "muddy" the discussion.
Many years ago, we made leading edge templates of a wing of an undamaged
and relatively new LS sailplane. The templates were made with bondo and
cardboard in the JJ manner. We all know the root is bigger/fatter than
the tip. We would slide the root template from the root to the tip and
observe the changing shape as it neared the tip.
We then took the root template to the other wing and did the same. They
were not same. Not even very close and we found the middle of the other
wing was actually fatter than the root.
This particular LS went we very, very well. It was a winner in many
competitions.
Conclusion?
Bob


>"Careful about free advice! It ain't just about waves". (previous
message)

[Frank Whiteley]

On Oct 21, 9:26*pm, "Bill Daniels" <bildan@comcast-dot-net> wrote:
> You know, I've been flying FX 67-150 and -170 airfoils for years. *I've
> smashed thousands of bugs, flown through many rain showers and even
> collected substantial ice on occasion yet I've not seen any unusual
> performance degradation when analyzing flights with SeeYou nor did I feel
> any in flight. *In fact, those glides with crappy wings often show a
> height/distance ratio well above the published L/D. *I know Bob Faris gets
> great results with his LS-3a in the same conditions. *I wonder if these
> airfoils are getting a bad rap.
>
Bob Faris flies an LS-3, which is rather different than an LS-3a in
the flap/aileron vs flaperon and wing weight areas. Read something in
the past year that suggested that the FX67/170 and 150 did not degrade
on long spans where the thickness was 15%, but can't find it at the
moment.

Frank Whiteley

[Uniform Zulu[_2_]]

The LS-3 measured higher in L/D than the 3a according to Dick Johnson's
tests. I actually have a letter from Wolf Lemke that was with papers that
came with my LS-3a assuring owners that there is no difference in
performace from follow-up factory tests of the 3a after Dick's flight
tests??

I also noticed the following quote on wikipedia for the LS-3:
"In spite of its weight the LS3 is a nimble climber. It is also less
sensitive to rain or dirt than other types with the same profile."

I'm not sure who posted this to the Wiki or if this applies only to the 3
or 3a? Was there any change in profile for the 3a?

Matt
LS3-a "RX"

At 15:44 22 October 2008, Frank Whiteley wrote:
>On Oct 21, 9:26=A0pm, "Bill Daniels" wrote:
>> You know, I've been flying FX 67-150 and -170 airfoils for years.
>=A0I've
>> smashed thousands of bugs, flown through many rain showers and even
>> collected substantial ice on occasion yet I've not seen any unusual
>> performance degradation when analyzing flights with SeeYou nor did I
>feel
>> any in flight. =A0In fact, those glides with crappy wings often show a
>> height/distance ratio well above the published L/D. =A0I know Bob
Faris
>g=
>ets
>> great results with his LS-3a in the same conditions. =A0I wonder if
>these
>> airfoils are getting a bad rap.
>>
>Bob Faris flies an LS-3, which is rather different than an LS-3a in
>the flap/aileron vs flaperon and wing weight areas. Read something in
>the past year that suggested that the FX67/170 and 150 did not degrade
>on long spans where the thickness was 15%, but can't find it at the
>moment.
>
>Frank Whiteley
>

[Uniform Zulu[_2_]]

The LS-3 measured higher in L/D than the 3a according to Dick Johnson's
tests. I actually have a letter from Wolf Lemke that was with papers that
came with my LS-3a assuring owners that there is no difference in
performace from follow-up factory tests of the 3a after Dick's flight
tests??

I also noticed the following quote on wikipedia for the LS-3:
"In spite of its weight the LS3 is a nimble climber. It is also less
sensitive to rain or dirt than other types with the same profile."

I'm not sure who posted this to the Wiki or if this applies only to the 3
or 3a? Was there any change in profile for the 3a?

Matt
LS3-a "RX"

At 15:44 22 October 2008, Frank Whiteley wrote:
>On Oct 21, 9:26=A0pm, "Bill Daniels" wrote:
>> You know, I've been flying FX 67-150 and -170 airfoils for years.
>=A0I've
>> smashed thousands of bugs, flown through many rain showers and even
>> collected substantial ice on occasion yet I've not seen any unusual
>> performance degradation when analyzing flights with SeeYou nor did I
>feel
>> any in flight. =A0In fact, those glides with crappy wings often show a
>> height/distance ratio well above the published L/D. =A0I know Bob
Faris
>g=
>ets
>> great results with his LS-3a in the same conditions. =A0I wonder if
>these
>> airfoils are getting a bad rap.
>>
>Bob Faris flies an LS-3, which is rather different than an LS-3a in
>the flap/aileron vs flaperon and wing weight areas. Read something in
>the past year that suggested that the FX67/170 and 150 did not degrade
>on long spans where the thickness was 15%, but can't find it at the
>moment.
>
>Frank Whiteley
>

[Uniform Zulu[_2_]]

The LS-3 measured higher in L/D than the 3a according to Dick Johnson's
tests. I actually have a letter from Wolf Lemke that was with papers that
came with my LS-3a assuring owners that there is no difference in
performace from follow-up factory tests of the 3a after Dick's flight
tests??

I also noticed the following quote on wikipedia for the LS-3:
"In spite of its weight the LS3 is a nimble climber. It is also less
sensitive to rain or dirt than other types with the same profile."

I'm not sure who posted this to the Wiki or if this applies only to the 3
or 3a? Was there any change in profile for the 3a?

Matt
LS3-a "RX"

At 15:44 22 October 2008, Frank Whiteley wrote:
>On Oct 21, 9:26=A0pm, "Bill Daniels" wrote:
>> You know, I've been flying FX 67-150 and -170 airfoils for years.
>=A0I've
>> smashed thousands of bugs, flown through many rain showers and even
>> collected substantial ice on occasion yet I've not seen any unusual
>> performance degradation when analyzing flights with SeeYou nor did I
>feel
>> any in flight. =A0In fact, those glides with crappy wings often show a
>> height/distance ratio well above the published L/D. =A0I know Bob
Faris
>g=
>ets
>> great results with his LS-3a in the same conditions. =A0I wonder if
>these
>> airfoils are getting a bad rap.
>>
>Bob Faris flies an LS-3, which is rather different than an LS-3a in
>the flap/aileron vs flaperon and wing weight areas. Read something in
>the past year that suggested that the FX67/170 and 150 did not degrade
>on long spans where the thickness was 15%, but can't find it at the
>moment.
>
>Frank Whiteley
>

[Uniform Zulu[_2_]]

The LS-3 measured higher in L/D than the 3a according to Dick Johnson's
tests. I actually have a letter from Wolf Lemke that was with papers that
came with my LS-3a assuring owners that there is no difference in
performace from follow-up factory tests of the 3a after Dick's flight
tests??

I also noticed the following quote on wikipedia for the LS-3:
"In spite of its weight the LS3 is a nimble climber. It is also less
sensitive to rain or dirt than other types with the same profile."

I'm not sure who posted this to the Wiki or if this applies only to the 3
or 3a? Was there any change in profile for the 3a?

Matt
LS3-a "RX"

At 15:44 22 October 2008, Frank Whiteley wrote:
>On Oct 21, 9:26=A0pm, "Bill Daniels" wrote:
>> You know, I've been flying FX 67-150 and -170 airfoils for years.
>=A0I've
>> smashed thousands of bugs, flown through many rain showers and even
>> collected substantial ice on occasion yet I've not seen any unusual
>> performance degradation when analyzing flights with SeeYou nor did I
>feel
>> any in flight. =A0In fact, those glides with crappy wings often show a
>> height/distance ratio well above the published L/D. =A0I know Bob
Faris
>g=
>ets
>> great results with his LS-3a in the same conditions. =A0I wonder if
>these
>> airfoils are getting a bad rap.
>>
>Bob Faris flies an LS-3, which is rather different than an LS-3a in
>the flap/aileron vs flaperon and wing weight areas. Read something in
>the past year that suggested that the FX67/170 and 150 did not degrade
>on long spans where the thickness was 15%, but can't find it at the
>moment.
>
>Frank Whiteley
>

[Uniform Zulu[_2_]]

The LS-3 measured higher in L/D than the 3a according to Dick Johnson's
tests. I actually have a letter from Wolf Lemke that was with papers that
came with my LS-3a assuring owners that there is no difference in
performace from follow-up factory tests of the 3a after Dick's flight
tests??

I also noticed the following quote on wikipedia for the LS-3:
"In spite of its weight the LS3 is a nimble climber. It is also less
sensitive to rain or dirt than other types with the same profile."

I'm not sure who posted this to the Wiki or if this applies only to the 3
or 3a? Was there any change in profile for the 3a?

Matt
LS3-a "RX"

At 15:44 22 October 2008, Frank Whiteley wrote:
>On Oct 21, 9:26=A0pm, "Bill Daniels" wrote:
>> You know, I've been flying FX 67-150 and -170 airfoils for years.
>=A0I've
>> smashed thousands of bugs, flown through many rain showers and even
>> collected substantial ice on occasion yet I've not seen any unusual
>> performance degradation when analyzing flights with SeeYou nor did I
>feel
>> any in flight. =A0In fact, those glides with crappy wings often show a
>> height/distance ratio well above the published L/D. =A0I know Bob
Faris
>g=
>ets
>> great results with his LS-3a in the same conditions. =A0I wonder if
>these
>> airfoils are getting a bad rap.
>>
>Bob Faris flies an LS-3, which is rather different than an LS-3a in
>the flap/aileron vs flaperon and wing weight areas. Read something in
>the past year that suggested that the FX67/170 and 150 did not degrade
>on long spans where the thickness was 15%, but can't find it at the
>moment.
>
>Frank Whiteley
>

[[email protected]]

I echo UH's cautionary remarks. My observations based on owning and
campaigning an LS-3 (not LS-3a) for 13 years, including profiling the
wings, plus speaking with another owner who profiled his wings:

1. The original LS-3, when new, was fully equal to the ASW 20 in both
climb and cruise. As time went on, many (most?) LS-3s seemed to
degrade in cruise. They always climbed well. I found that the lost
cruise performance could be regained by sanding/smoothing the waves
out of the wings. A polished finish isn't necessary. I know guys who
used 600 grit all the way down to 220 grit, although the latter was
tough to live with as it collected fingerprints and dirt. THe matte
finish was an attempt to have water droplets (rain) spread rather than
bead up because this airfoil was notable for being sensitive to rain.
That said, the last time I worked on mine, I waxed it up and flew it
through rain several times in a contest and it seemed to go fine. One
PIK driver told me the secret to that glider (same airfoil, panicky in
the rain) was to fly it with more flap than spec'd when there was rain
and that's what I did.

2. Eventually you can't smooth the wing enough by sanding. The problem
is curing over the spar caps. The airfoil develops flat spots so
severe that you'll sand into the fiberglass trying to make them go
away. Not unique to the LS-3 but a particular problem. Building these
flat spots back up to the approximate contour restores the cruise
completely and makes the airplane equal to the ASW 20 (including B),
the Ventus 1, and the LS-6. It's a lot of work. Don't let anyone just
remove the gel coat and spray the wing, sand, polish, and expect it to
work right. On this specific model, the underlying structure is not
correct. Unless you correct the flat spots cause by shrinkage over the
spar caps, it will climb great but it won't cruise as well as these
other gliders.

3. THe LS-3a (split flap/aileron, bigger tail, some with 17m tips) was
reputed to have a thicker wing on some gliders because of mold
distortion at the factory. That story was the reason for the factory's
letter assuring everyone that the wing profiles of the 3 and 3a were
the same. Some 3a's were great gliders, others were far inferior in
cruise. I suspect all could be corrected by working on the profile. As
UH suggests, read the Dick Johnson series on his PIK 20. It's very
similar work. The coordinates are public domain and you don't need the
factory's help. The "different sets" of coordinates relate to two sets
of revised numbers that corrected small errors in the original
published coordinates. All were in Soaring magazine (and elsewhere,
I'm sure), though the last set was in a letter to the mag, IIRC).

4. The leading edge of the LS-3 wing from the factory was not as sharp
as it should have been, especially in the outer section. The owner I
spoke with corrected this, too. I don't know how much effect this had
and I didn't do it. If you're profiling the whole wing, this will show
up, obviously (esp. in JJ's first 4 inches, although not if you use
the existing airfoil as the mold). If you're going after bang for the
buck, you could probably focus on the wing over the spar caps if the
rest of the gel coat is OK.

5. I found a small but noticeable improvement from installing
turbulator tape on the lower surface. I don't recall how far back; we
did it by trial and error flying against George Moffat's Ventus. I
also played with various flap settings and discovered that the full 10
degrees isn't usually necessary although it's easier to thermal that
way. 5 or 7 degrees works better most of the time.

6. I don't know if anyone ever put winglets on a 3 but I suspect they
would improve the glider as much as they do other gliders, in
particular with the way the flaperon extends all the way out to the
tip.

These gliders were essentially abandoned by most serious pilots
decades ago (Manfred Franke here in the US is one notable exception).
But when properly prepared, they still offer great performance, are
very strong, and handle nicely. There are several at our airport that
perform well even though the finish is less than perfect.

Chip Bearden
ASW 24 "JB"
USA