Hey Jason,

As you said, it’s difficult to tell if there is negative incidence. And, yes, yours looks level, but 1 degree of down incidence is difficult to detect without an incidence meter. And, even -1 degree will make a difference, especially on a high performance jet.

I don’t have TV, so I’m sorry that I don’t know the answer. With others I have helped with their different TV jets. I learned that the VT pipe changes when heated. It can be trimmed zero-zero when the engine isn’t running. After the starts and heats the pipe, the TV pipe will have moved a couple degrees of either up-down or left and right, and even both directions. So trim it hot standing over the tail and looking from the side.

If you’re familiar with Robart’s jeweled incidence meter. It can be used to see if the jet has negative incidence. It is used on the wing. Moving the retract to the other side of the mount was the last thing I did after making sure the W/B was where I wanted it to be. I use the knife edge to trim the balance. I want it to be neutral with no tuck or pull, and no mixes. Because most jets start off nose heavy, it pulls to the canopy in knife edge. I move batteries aft until it tracks true and straight without any mixes. After I did that, it still would jump off the ground. Because of another jet I had experienced the negative incidence, is how I SWAG the Diablo has negative incidence. Moving the retract to the other side of the mount is how I solved it. I didn’t want to buy a longer nose strut.