Zero Lift angle?

[AirFox]

I'm installing Advanced flight systems AOA air ports in my Super Sport wing. I am wondering if anyone knows the zero lift angle of the wing relative to the cord line? The differential air pressure ports get installed at a distance from the leading edge of the wing where the zero lift line intersects the mean distance between the top and bottom surface of the wing.
4347

More information on the AOA system is available at this link. See the power point presentation.
http://www.advanced-flight-systems.com/Support/AOAsupport/aoasupport.html

Thanks for any input.

Scott

[AirFox]

Looks like the zero lift line didn't show up the the attached picture. It goes from the trailing edge through the circled 6 at the leading edge of the wing.

[Av8r3400]

Aren't AOA meters usually calibrated through flight testing?

The meters that I have seen installed used a level forward pitot tube along with a 45 degree down angle AOA tube. Then tweaking adjustments of the down tube were made during flight testing.

[AirFox]

Av8r3400,

Advanced AOA system uses differential pressure ports on the top and bottom of the wing. This way the lift the wing is producing is actually the measurment for the AOA system. This system is supposed to give better AOA indications than the Pitot systems out there. I am looking for the Zero Lift angle in order to locate the pressure ports. Every wing design has it's own Zero lift angle where the wing produces no lift or drag.

Thanks for any help.

Scott

[HighWing]

I doubt you will be able to find the answer here or at the factory. It is a term that has appeared just once in the almost 20 years I have been involved with Kitfox - first kit delivery 3/93. The term appeared earlier today;)

After reading your initial question, I went online and checked your unit and one I bought about 7 years ago - still uninstalled. I also looked at some user comments. Then your comment about the claims of better AOA indications made me think of how sensitive our control inputs are and how close to actual stall we will be willing to fly. Also LED readouts are only as sensitive as the steps between the light bars. My guess is that what you are looking for are base line measurements to determine approximate best location of the ports. If they were positioned exactly right, you would have no need for the calibration steps on the later pages of the install manual. I suspect you will position the ports the best you can and then use the calibration steps to fine tune the panel readout. And then, if you are like the guys that posted comments on some of the other units, fly with the light at least a couple of steps above stall.
Lowell

[t j]

The kitfox IV and later airfoils seem to be a Riblette GA30U-612, if that helps. I get very confused trying to understand the effect that flapperons have on that airfoil.

[AirFox]

Thanks for the info guys. Tom I'll see if I can find some information on Riblette GA30U-612.

Scott

[kebopa3]

Scott,
I'm sitting here waiting on Partain to show up and thought I'd do some internet searching for you. Obviously I can not speak to it's the accuracy but it should be be easy to lay out with a smart level.

More info on the 4412 - Ribblet GA30U-612

the angle of zero lift = -4.13 deg

ideal angle of attack = 0.48 deg

Moment coefficient Cm0/4 = -0.106

Here is the link to the source as well.
http://groups.yahoo.com/group/kitfoxlist/message/39394

kebo

[AirFox]

Good find Kebo! Thanks for using your spare time wisely. Glad to year your delivery will be soon! That was a fun day for me. 4 months later & I'm ready to cover.

Thanks

Scott

[kebopa3]

Scott,
How did the AOA sensors turn out? How about a couple of pictures? I'm a long way from having to make a decision concerning my panel but I'd like to see your set-up.
Thanks
Kebo

[AirFox]

Hi Kebo,

I put some pictures of my installation in my wing album.
http://www.teamkitfox.com/Forums/album.php?albumid=298 (http://www.teamkitfox.com/Forums/album.php?albumid=298)

4539
After talking with John McBean and Rob Hickman at Advanced Flight Systems I installed the ports as shown in my photos. The key to installing the AOA ports in the Kitfox is to be sure that there is no air leaks between the ports and the surface of the wing. You can see in my pictures that I attached the ports to Aluminum cutouts. I used Silicone adhesive to seal the port to the aluminum. I will glue the fabric to the aluminum plates to seal the fabric to the the plate.

If your going with Advanced flight systems then take a look at the AHRS magnitometor mount in the pictures. I placed the mount out in the wing to avoid interference with the fuselage. I pancaked Aluminum to be tapped for The mounting screws. That way the AHRS can be accessed and removed with brass screws through an inspection hole. I located the AHRS as close to the Centerline of the fuselage to avoid offset calculation errors in the AFS 5600. I used washers to eliminate the Dihedral and twist in the wing, so the AHRS will be level with my flight path. I'll let you know how it turns out when I finish.
4540

Thanks

Scott