Turb tape Grob 104

I have heard that putting turb tape on the TOP of the wing on the G
104 wing will improve performance. I have heard of putting it on the
bottom but not on top. I would like to give it a try but am uncertain
where to place the tape. It is the Eppler 662 airfoil.

thanks

My recommendation:
for climb Cl 1.2
Top, +7deg Flap, 68% chord
bottom + 7deg Flap 66% chord

for cruise Cl .3
Top -6 deg Flap 65% chord
Bottom - 6 deg Flap 70% chord

I would go with the first set of numbers in each case, as this would give
you
max performance. One thing to consider with the 68%set-up,
in cruise the transition takes place early as noted above.
There is the possibility that the flow will still separate because
the turbulator is not in the right place for cruise, or if it will
transition to an attached flow and the 68% turbulator will make the
attached turbulent flow separate. If this is the case you must
move the turbulator to the 65% position. You then will capture
both climbing and cruising modes. Also make sure the the wing
surface is up to spec.

The bottom surface is less senitive, I would place the
turbulator at 70% chord
Regards
Udo




"Dave Kuchenbecker" wrote in message
om...
I have heard that putting turb tape on the TOP of the wing on the G
104 wing will improve performance. I have heard of putting it on the
bottom but not on top. I would like to give it a try but am uncertain
where to place the tape. It is the Eppler 662 airfoil.

thanks

Udo Rumpf wrote:
My recommendation:
for climb Cl 1.2
Top, +7deg Flap, 68% chord
bottom + 7deg Flap 66% chord

for cruise Cl .3
Top -6 deg Flap 65% chord
Bottom - 6 deg Flap 70% chord

I would go with the first set of numbers in each case, as this would give
you
max performance. One thing to consider with the 68%set-up,
in cruise the transition takes place early as noted above.
There is the possibility that the flow will still separate because
the turbulator is not in the right place for cruise, or if it will
transition to an attached flow and the 68% turbulator will make the
attached turbulent flow separate. If this is the case you must
move the turbulator to the 65% position. You then will capture
both climbing and cruising modes. Also make sure the the wing
surface is up to spec.

The bottom surface is less senitive, I would place the
turbulator at 70% chord
Regards
Udo




"Dave Kuchenbecker" wrote in message
om...

I have heard that putting turb tape on the TOP of the wing on the G
104 wing will improve performance. I have heard of putting it on the
bottom but not on top. I would like to give it a try but am uncertain
where to place the tape. It is the Eppler 662 airfoil.

thanks


Are there ever been made measurements (IDA?) of the improvements by
placing turbulator tapes on Eppler airfoils? My Standard Astir II
(Eppler E603) has turbulator tape on the bottom.

Thanks

"Noël De Corte" wrote in message
...


Udo Rumpf wrote:
My recommendation:
for climb Cl 1.2
Top, +7deg Flap, 68% chord
bottom + 7deg Flap 66% chord

for cruise Cl .3
Top -6 deg Flap 65% chord
Bottom - 6 deg Flap 70% chord

I would go with the first set of numbers in each case, as this would
give
you
max performance. One thing to consider with the 68%set-up,
in cruise the transition takes place early as noted above.
There is the possibility that the flow will still separate because
the turbulator is not in the right place for cruise, or if it will
transition to an attached flow and the 68% turbulator will make the
attached turbulent flow separate. If this is the case you must
move the turbulator to the 65% position. You then will capture
both climbing and cruising modes. Also make sure the the wing
surface is up to spec.

The bottom surface is less senitive, I would place the
turbulator at 70% chord
Regards
Udo




"Dave Kuchenbecker" wrote in message
om...

I have heard that putting turb tape on the TOP of the wing on the G
104 wing will improve performance. I have heard of putting it on the
bottom but not on top. I would like to give it a try but am uncertain
where to place the tape. It is the Eppler 662 airfoil.

thanks


Are there ever been made measurements (IDA?) of the improvements by
placing turbulator tapes on Eppler airfoils? My Standard Astir II
(Eppler E603) has turbulator tape on the bottom.

Thanks

The E 603 will improve with a turbulator on the bottom only.
I do not remember off hand the position.
The E604 is an update on the 603 and takes this into account.
No turbulator required on that one.
Udo

Thanks Udo, I will give it a try.




"Udo Rumpf" wrote in message ...
My recommendation:
for climb Cl 1.2
Top, +7deg Flap, 68% chord
bottom + 7deg Flap 66% chord

for cruise Cl .3
Top -6 deg Flap 65% chord
Bottom - 6 deg Flap 70% chord

I would go with the first set of numbers in each case, as this would give
you
max performance. One thing to consider with the 68%set-up,
in cruise the transition takes place early as noted above.
There is the possibility that the flow will still separate because
the turbulator is not in the right place for cruise, or if it will
transition to an attached flow and the 68% turbulator will make the
attached turbulent flow separate. If this is the case you must
move the turbulator to the 65% position. You then will capture
both climbing and cruising modes. Also make sure the the wing
surface is up to spec.

The bottom surface is less senitive, I would place the
turbulator at 70% chord
Regards
Udo




"Dave Kuchenbecker" wrote in message
om...
I have heard that putting turb tape on the TOP of the wing on the G
104 wing will improve performance. I have heard of putting it on the
bottom but not on top. I would like to give it a try but am uncertain
where to place the tape. It is the Eppler 662 airfoil.

thanks