UIUC Low-Speed Airfoil Tests

Wind Tunnel Model Construction Notes - Supplement for Flapped Models (Version 5f)

Materials Supplied

Important Note

The flap endplates will be reused on other models, so do not permanently glue them to the model.


The Basic Model

Alternate Flap Bracket

Important: This method should only be attempted by experienced builders who are sure that the endplates will automatically be located in the same place every time they are removed and re-assembled. See drawing E for an example of an endplate recess that will ensure the plate can only be mounted in one position.

Flap Installation

Cutout the 21% chord flap, which is 2.52 inch for a 12 inch chord model. Use a standard V-type cutout as shown in drawing C. The V-cutout should only be large enough to allow for a -15 reflexed flap deflection. All models will use the V-type cutout to be consistent; we will use a mylar gap seal on the model during the tests.


Check to make sure that all flap positions can be set with the alignment pin and secured with the 2-56 screw.

Final Comment

In the wind tunnel, we will tape over all holes in order to maintain good flow integrity. For this purpose, we have a special tape that is easily removable, so you need not do this step.

Non-Standard Flap Chord Lengths

For flap chords greater or less than 21%, the endplate will still work. The only change is that the aft alignment hole R, will not line up with the trailing edge. It is necessary, of course, that the hinge line remain at point S. If you contemplate using a non-standard flap chord, please call us first.


If you have any questions, please contact Prof Michael Selig.

If you have any suggestions for improvements, please send them to us. If you would like to provide us with a sheet of notes: "lessons learned" we will include them with these instructions. On your notes, please list your name and phone number in case a builder would like to ask you questions.

Shipping of Models

See notes here: modelNotes.html

Example of standard flap bracket

Detail of one flap endplate installation.

We prefer this (below): Example of alternate music wire flap bracket - see text before attempting this method. (Model by Jerry Robertson). Note recessed plate.

===>MORE pictures of a flap endplate install.
Flap retrofit by Jerry Robertson
Model by Yvan Tinel
(2.4 MB)

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