tuft testing

On Wed, 27 Oct 2004 15:56:11 GMT, "keepitrunning"
wrote:

I was reading and saw a picture of a wing being tuft tested. I was
wondering, since I do not have a clue, how much difference the tape holding
the tufts would cause. In the picture it appears that 1/2 inch blue masking
tape was used and it was torn rather than cut. The tufts were spaced a
couple of inches apart and there were seven rows and eight columns. His
results were that the wing was not showing any separation. Just wondering
if there are accepted methods of doing this type of testing? How would you
determine where to test? Any discussion and comments would be appreciated.

tufting is useful for checking that flows are remaining laminar and in
trying to identify drag sources due to turbulence.

you use a tape which can be peeled off without ripping up the paint.
vinyl gaffer tape is ideal. the wool is any contrasting colour and at
about 8ply thickness. the tuft is about 6-8 inches long.

you tape about an inch or so of the wool. the tape should remain
within the boundary layer with the wool getting out into the airstream
eventually.

accepted methods? nah, use whatever works. it isnt rocket science.

where to test? anywhere which looks like further improvement is
possible. it should be obvious but you need to tuft where you can see
or photograph the tufts. if you cant see the tufts you will need
another aircraft to formate in flight.

what do you find out? well sometimes nothing but often you get to see
what the air is doing.

try a few tufts on the bonnet and windscreen of your car.
Stealth Pilot