Vertical tail improvements

[pgkirsch]

The following improvements need to be made to the vertical tail model:

• Constrain taper by something like minimum Reynolds number for tip stall
• Improve the weight model

(list is work in progress)

[whoburg]

I'm not sure whether or not tip stall is an issue for vertical tails.

[pgkirsch]

Well being able to avoid stall at high angles of attack is important for tails, and I figured that it would stall at the tip first.

[pgkirsch]

I do have a better model in mind for constraining taper though -- Horner (1950 something) has some empirical models to related span efficiency to taper (see the latest version of htail for example). The optimum according to that model is somewhere around 0.3.

[whoburg]

sounds good. Yeah stall obviously matters, but the usual deal with tip stall is that stalling at the tip first can lead to large roll deviations and unresponsive ailerons. I'm not sure any similarly bad effects occur if a tail stalls first at the tip vs somewhere else. the span efficiency approach sounds like a good approach to start!