Page 17 - Volume 11 Number 9

Because the elevators reside in this accelerated airflow once power is applied, they are quite effective even at low speed. The T-tail elevators, on the other hand, reside above the prop wash. At low speed, they are ineffective. Only when airspeed increases enough do the elevators experience sufficient airflow to become effective. It’s been said that the T-tail elevators have an On-Off switch: Off below about 60 knots and On above that. Be prepared for sudden elevator effectiveness as the airspeed picks up in the T-tailed King Airs. Only when going 60 knots or more may you start trying to find the neutral pitch point.
When the runway is long enough, a delayed rotation is not harmful and, in fact, can be desirable. It provides a cushion of extra airspeed and energy that we can utilize when/if we are confronted with an engine failure at this critical time. The negative here is that Accelerate-Stop Distance increases with the higher V1/VR – in most King Airs they are the same value – but if the runway is longer than we need, so what?
The point I am trying to make is that a delayed rotation is not always a bad thing, On the other hand, however, when the runway is short enough to leave us little or no room for error, then we need to do all that we can to properly mimic the test conditions. There is no way to achieve that goal unless we “lighten up” the control wheel rather early in the takeoff roll.
Let’s consider an abort, right near VR. In this situation, lightning up is just the opposite of what we should do. As soon as the right hand pulls the power levers to Idle – and then to Ground Fine or Reverse for some models – the left hand should eliminate all back pressure on the wheel and, instead, push the wheel fully forward. Many airplanes, including some King Airs, exhibit a strong pitch-up tendency when forward thrust suddenly turns into drag or negative thrust. Push forward to make sure the nose tire remains firmly planted on the runway such that directional control is optimized.
You will know that you have learned to lighten up correctly when rotation is so smooth that it is difficult for the passengers to know when they stopped rolling and started flying. Try it. You’ll see! KA
King Air expert Tom Clements has been flying and instructing in King Airs for over 44 years, and is the author of “The King Air Book.” He is a Gold Seal CFI and has over 23,000 total hours with more than 15,000 in King Airs. For information on ordering his book, contact Tom direct at twcaz@msn.com. Tom is actively mentoring the instructors at King Air Academy in Phoenix.
If you have a question you’d like Tom to answer, please send it to Editor Kim Blonigen at kblonigen@cox.net.
SEPTEMBER 2017
KING AIR MAGAZINE • 15