Tail Wag

[zav6a]

I've been reading posts on tail wag and was reminded of an observation made many times over during the course of the last summer. When flying in buggy weather, I noticed that only the outer half of the horizontal stabilizers and the top half of the vertical stabilizer had bugs stuck to the leading edge. Surfaces closer to the tail cone were clean. I'm guessing that the flow over the fuselage is disrupted, perhaps to the point detaching and the non-laminar flow has less impact energy, hence no bugs.

In addition to the oil canning and eddy flow around the rudder that have been offered as potential causes of wag, I wonder if the effective area of the vertical stabilizer is limited by this phenomenon, leading to a bonanza-like wag.

Considering that the trim tab is in the inner portion of the stabilzer, it would seem that trim authority may be compromised as well.

I'm tempted to put some VGs on the fuselage and canopy and go fly. I'll use the bugs as my tufts. If the detachment is as significant as it seems, there might also be some more speed to be had.

Anybody notice or try the same thing?

[Kevin Horton]

Originally Posted by zav6a

I've been reading posts on tail wag and was reminded of an observation made many times over during the course of the last summer. When flying in buggy weather, I noticed that only the outer half of the horizontal stabilizers and the top half of the vertical stabilizer had bugs stuck to the leading edge. Surfaces closer to the tail cone were clean. I'm guessing that the flow over the fuselage is disrupted, perhaps to the point detaching and the non-laminar flow has less impact energy, hence no bugs.

Bugs have a lot more mass than air. Very light particles will follow the air as it follows the surface contours. Heavier items tend to keep going in a straight line. The bugs that would have hit the inner portion of the HS or VS leading edges have already hit the biggest parts of the fuselage.

If you drive at night in a snow storm with big fluffy snow flakes, you can observe the snow flakes rising to go over the car's windshield as they are following the air. But, bugs have more mass, and they hit the windscreen.

Don't worry about where the bugs hit. Just be happy there are a few less places to clean.