Elevator Turbulator tape question

I'm planning on trying turbulator tape (zig-zag, probably) on the
horizontal tail of my Ls-6, in front of the elevator. Anyone have any
experience doing this?

I added .4 mm ziz-zag to to the elevator of my LS-7 and it changed the stall
dramatically. Before adding it, the ship stalled like an old cow, with the
zig-zag, she broke and showed me a windshield full of mother earth. I took it
off.
:)
JJ Sinclair

(JJ Sinclair) wrote in message ...

I added .4 mm ziz-zag to to the elevator of my LS-7 and it changed the stall
dramatically. Before adding it, the ship stalled like an old cow, with the
zig-zag, she broke and showed me a windshield full of mother earth. I took it off.

Interesting. Sounds like the zig-zag really improved the elevator
effectiveness at large defections. Good info, I'll definitely check
that out!

One question - where did you put the tape? top & bottom?, how far in
front of the elevator?

Kirk

One question - where did you put the tape? top & bottom?, how far in
front of the elevator?

Just forward of the hinge line, top only, as I recall. I put the wide Mylar
with zig-zag on forward edge on the rudder, seemed to help there.
JJ Sinclair

In article , stant2
@mindspring.com says...
(JJ Sinclair) wrote in message ...

I added .4 mm ziz-zag to to the elevator of my LS-7 and it changed the stall
dramatically. Before adding it, the ship stalled like an old cow, with the
zig-zag, she broke and showed me a windshield full of mother earth. I took it off.

Interesting. Sounds like the zig-zag really improved the elevator
effectiveness at large defections. Good info, I'll definitely check
that out!

Do you consider it an improvement to get a sharp stall, or is there some
other effect you hope to get with "improved elevator effectiveness"?
--
-------
Eric Greenwell USA

Eric Greenwell wrote in message et...

Do you consider it an improvement to get a sharp stall, or is there some
other effect you hope to get with "improved elevator effectiveness"?

How else can I get my 6 to snap roll!

Seriously, this was suggested by an experience 6 racer, theory is that
it allows more precise elevator control while thermaling and less
drag. Worth a try. I'm not particularly concerned about sharp
stalls, I love the 2-32 (which has a particularly sharp break for a
glider) and think all pilots should be required to fly (and stall) a
T-6 to see how a real plane flies.

I am curious about which side (top or bottom) of the horizontal stab
should have the turbulator. Intuition tells me it should be on the
bottom, to energize the airflow around the up deflected elevator.

Anyway, it might be fun to find out. Especially since it is a totally
reversible mod.

BTW, two of us flew a 220 mile XC out here in AZ today - 1400' agl
release off tow, Cu's, cloudbase at 12000'. 50 mile final glide under
a thick cirrus deck, started with 350' over a 1 knot MC (!) and made
it home with enough to do a 130 kt low pass (down a runway). Other
guy did 240, and a 65 mile final glide. He beat me, 54 mph to 52 mph.

And we were definitely NOT at 500ft at 1 mile!

Yee hah! I love this sport.

Kirk
66

and think all pilots should be required to fly (and stall) a
T-6 to see how a real plane flies.

I have lots of time in a T-6 and I am of the opinion that newer designs are
much better. Why not train with aircraft that characteristics of the ones we
fly. The T-6 is heavy, underpowered (in my opinion) has a sharp stall break
and snaps into a spin very easy. There has been several accidents that I know
where a pilot was flying at a heavier weight than normal used a sharp break in
the base to final turn and spin in. I like flying a T-6 but cannot recommend
them for all.

Craig

(Kirk Stant) wrote in message
I am curious about which side (top or bottom) of the horizontal stab
should have the turbulator. Intuition tells me it should be on the
bottom, to energize the airflow around the up deflected elevator.


Kirk,

My 28 has turb tape on top, as delivered. I don't remember if it's on
the bottom too. The measurements for all turbulator positions are in
included in the maintenance manual. If you want more info call me at
home this weekend. (Your ras email seems to be invalid).

BTW the 28 stall is very docile at the aft cg limit.

Andy (GY)

I would encourage a lot of caution before slapping turbulator tape on
the elevator or elsewhere upwind of control surfaces. There have been
several instances of pilots crashing or having to abandon gliders
because mylar or tape became loose on elevators. If your turbulator
tape causes separation rather than good turbulent flow, you might
follow them. Turbulator tape on the top of wings has caused really
nasty stall/spin problems. Why be a test pilot? Call the
manufacturer! SH was nice enough to provide advice on where I should
put the tape on my old discus.

John Cochrane

Kirk,
I agree with you that competent, current pilots, don't inadvertently stall any
ship. But your statement that you like a crisp stall, got me wondering. How do
you like a crisp stall, in the pattern, after some hard maneuvering to avoid a
mid-air? How do you like a crisp stall, when on the rocks, and get hit with a
large tail-gust?

The stall I got in my LS-7, after adding zig-zag to the horizontal stab, was
the worst stall I have ever seen in any sailplane. I mean she went near
vertical on me. Don't care to duplicate that in the above situations.

PS, I suspect the zig-zag delayed the *normal* seperation on the stab, but when
it did seperate, I lost all the down force from the horizontal stab and that
gave me the near vertical pitching moment. The wing may not have stalled at
all. Now someone please feel free to tell me just how full of Ka-ka, I am about
aerodynamics.
:)
JJ Sinclair

JJ, you are about right on. I strongly suspect that if a glider "stalls"
but retains aileron control, the wing didn't really stall - just the
horizontal tail lost its grip on the air and let the tail pop up (Nose pops
down). Normally, this is a pretty benign way to limit minimum airspeed.
Adding any device to increase up elevator authority might allow the pilot
bring the whole wing to stall with the possibility of a spin departure.

It seems to me that the only reason to increase up elevator authority would
be to improve thermaling and then only in the case of a glider whose minimum
airspeed is limited by up elevator ineffectiveness. A case might be the
G103 Twin II when the CG is near the forward limit. This limits minimum
airspeed to well above minimum sink in a steep turn.

Bill Daniels

"JJ Sinclair" wrote in message
...
Kirk,
I agree with you that competent, current pilots, don't inadvertently stall
any
ship. But your statement that you like a crisp stall, got me wondering.
How do
you like a crisp stall, in the pattern, after some hard maneuvering to
avoid a
mid-air? How do you like a crisp stall, when on the rocks, and get hit
with a
large tail-gust?

The stall I got in my LS-7, after adding zig-zag to the horizontal stab,
was
the worst stall I have ever seen in any sailplane. I mean she went near
vertical on me. Don't care to duplicate that in the above situations.

PS, I suspect the zig-zag delayed the *normal* seperation on the stab, but
when
it did seperate, I lost all the down force from the horizontal stab and
that
gave me the near vertical pitching moment. The wing may not have stalled
at
all. Now someone please feel free to tell me just how full of Ka-ka, I am
about
aerodynamics.
:)
JJ Sinclair