While flight testing a modification on a Siai Marchetti 1019 last winter, I found it had a rather poor stick force gradient at the takeoff flap setting (30). I had a couple of rathe scary takeoffs, when a large pitch push force was required immediately after becoming airborne. It was controllable if you were ready for it, but a real surprise the fist few times.
I did some data gathering, and the following graphs are extracted from my report. The aircraft was near gross weight and forward C of G for all this testing, control forces trimmed to zero at 70 KIAS, and all other things remained unchanged. "pounds" is stick force in pitch, with a pull force being positive pounds (you'll see some negative
), "Tq" is engine torque in percent (Allison C250-C17 turbine). The rest is self evident.
And here is the view of the elevator I took from the back seat while training the company pilot. Unaccelerated flight, trimmed to 60KIAS, flaps 60, and no more nose down pitch control available! (If you want to nose down, you have to either remove some flaps or some power).
