This will probably stir some controversy but I think it is important to stay safer in a IV.

There is recent discussion about AOA and vortex generators with the IV and I will leave that to owners preferences. I believe the real issue with the IV is the rapidly increasing sink rate below 95 knots. Like all really high performance aircraft, slowing results in very significant power off sink rates well above stall. The high wing loading inherent in these aircraft is the reason for the speed/efficiency and the trade off is the sink. For pilots not used to this class of aircraft when slow, pulling back hoping to climb results in a very unfamiliar rapid loss of speed with no change in descent rate. Unless back pressure is relaxed quickly the remaining speed above stall dissipates very quickly. Once the departure comes, adding power just aggravates the spin.

The main thought is to stay above 100 knots so as to stay high enough on the speed curve to give a normal feel/result to the controls. The recommended 120 knots in the pattern and 100 knots over the fence meets this demand. If you have an AOA in your IV and can get it to blow the whistle at 95 knots I suggest you do so.

Those who would add vortex generators or an AOA so they can purposely operate the IV near stall are venturing into a potentially very dark place with little to be gained. Most aircraft in this class are turbines/jets and the operating manuals don't allow stalls or very slow flight.

Jack Morgan