Ka-6 TE Probe

Or buy a vario with electronic compensation and forego the probe all
together.
John Cochrane
BBG

I had a nice vertical fin installation on my Ka-6E. Roger Frank did the
work. It was quite "spendy"; however, worked great.
(http://www.soaridaho.com/photogallery/valley/Ka-6E.jpg)

Wayne
HP-14 "6F"
http://'www.soaridaho.com/Schreder


wrote in message
...
On Aug 28, 12:24 pm, vontresc wrote:

Take the time to put it in the fin. This keeps it out of the wing
root wash and will make
the variometer reflect what the glider is doing instead of how it
responds to effect of gusts
on wing root.
It may be easier than trying to work as far behing wing root as it
should go.
Just put one in a K-21 fin and it is MUCH better than aft fuselage.
Good Luck
UH

Like JJ said

If you want to do it easy and perfectly adequate as well, install a
nearly vertical tube ahead of the canopy near the bulkhead ahead of the
instrument panel (above the static buttons on the side of the fuselage).
I would suggest angling it slightly forward at the top so that the
tube is about perpendicular to the upwash induced by the wing. The top
of the tube could be about 6-8" outside the fuselage. Plug the top end
and put the hole or holes or slots in the back of the tube as drirected
from your favorite article by Oran Nicks' (Nicks tube) or Dick Johnson
or insert other favorite name here. The plumbing is short, easy to
do, and will give a reading that is well compensated. Our club Ka6CR
has one like this and it works well.

I would not suggest over the wing in the turtledeck, since it could
require uncoupling and coupling the pressure tube with some regularity
and it would be easy to damage when the turtledeck is off.

The position on top of the fuselage near the trailing edge of the wing,
however is not a bad one. The flow around the wing is nearly back to a
freestream static condition at the trailing edge and the flow had better
be attached while cruising or thermalling or there are other problems.
If one flys slow enough to separate the flow there, the inboard wing is
already stalled and that's flying too slow.

...... Neal

JJ Sinclair wrote:
Eric wrote.......

So, I'd suggest trying the very easiest thing first: a TE probe mounted
on the removable turtledeck, probably towards the rear it. If it works,
great; if not, very little effort wasted.


Yeah, what he said......................I used a vertical TE probe on
my Duster a hundred years ago and it worked as good as I did. If your
intimidated my the thought of drilling and stringing tubes, go the
easy way, it can be mounted forward of the canopy where there isn't
any interference with the wings. Wings & Wheels sells them and I
believe the top bent portion in set to be vertical with the ship set
in flying position (W&B level)
JJ

On Aug 28, 7:05*pm, Neal Pfeiffer wrote:
Like JJ said

If you want to do it easy and perfectly adequate as well, install a
nearly vertical tube ahead of the canopy near the bulkhead ahead of the
instrument panel (above the static buttons on the side of the fuselage).
* I would suggest angling it slightly forward at the top so that the
tube is about perpendicular to the upwash induced by the wing. *The top
of the tube could be about 6-8" outside the fuselage. *Plug the top end
and put the hole or holes or slots in the back of the tube as drirected
from your favorite article by Oran Nicks' (Nicks tube) or Dick Johnson
or insert other favorite name here. *The plumbing is short, easy to
do, and will give a reading that is well compensated. *Our club Ka6CR
has one like this and it works well.

I would not suggest over the wing in the turtledeck, since it could
require uncoupling and coupling the pressure tube with some regularity
and it would be easy to damage when the turtledeck is off.

The position on top of the fuselage near the trailing edge of the wing,
however is not a bad one. *The flow around the wing is nearly back to a
freestream static condition at the trailing edge and the flow had better
be attached while cruising or thermalling or there are other problems.
If one flys slow enough to separate the flow there, the inboard wing is
already stalled and that's flying too slow.

..... Neal



JJ Sinclair wrote:
Eric wrote.......

So, I'd suggest trying the very easiest thing first: a TE probe mounted
on the removable turtledeck, probably towards the rear it. If it works,
great; if not, very little effort wasted.

Yeah, what he said......................I used a vertical TE probe on
my Duster a hundred years ago and it worked as good as I did. If your
intimidated my the thought of drilling and stringing tubes, go the
easy way, it can be mounted forward of the canopy where there isn't
any interference with the wings. Wings & Wheels sells them and I
believe the top bent portion in set to be vertical with the ship set
in flying position (W&B level)
JJ- Hide quoted text -

- Show quoted text -

If objective is just simple installation, do what JJ says and put it
on the nose.
Putting it anywhere close to the flow field of the wing- that is
anywhere near the top, means that the local pressure
changes every time you change angle of attack. This is the reason why
it is on the fin on essentially all modern gliders.
UH

The fin is not the only location for good compensation.

A total energy probe works best when the flow passes by it at nearly the
same angle and at nearly freestream static pressure for the range of
speeds of interest.

Mounting in front of the fin puts the probe in a location that is close
to the freestream static pressure. The flow angularity may vary some
amount, but the combination of glider angle of attack and the downwash
field of the wing will tend to reduce the overall variation in flow
angle. Changing flap position will induce a step change in flow angle,
but again this is not too large.

Mounting the probe on the top of the fuselage a little aft of the wing
again puts the probe in a region that is close to freestream static
pressure and the straightening effect of the wing and fuselage produce
only a very small change in the flow angle at the probe.

Now, what about the forward fuselage? For a Ka6, the static buttons are
on the side of the fuselage at the bulkhead ahead of the instrument
panel, where they register near the freestream static value for the
thermaling and cruise conditions. On the top of the forward fuselage,
the canopy will slow the flow at its base, producing higher than
freestream static pressure, and then rapidly accelerate the flow as it
moves up and over the curved portion of the canopy, thus producing a
lower than freestream pressure. By placing the probe at the bulkhead
ahead of the panel, it is enough ahead of the canopy disturbance to have
a pressure value that is close to freestream, but possibly with more
variability than for the other two locations mentioned above. The pitch
flow angularity is pretty constant though. For the Ka6 with the speeds
mostly between 40 to 70 knots, the forward position is reasonable.

...... Neal


wrote:


- Show quoted text -


If objective is just simple installation, do what JJ says and put it
on the nose.
Putting it anywhere close to the flow field of the wing- that is
anywhere near the top, means that the local pressure
changes every time you change angle of attack. This is the reason why
it is on the fin on essentially all modern gliders.
UH