Page 19 - Volume 12 Number 4

levers rapidly while monitoring
torque and ITT. I guess that by
now you are quite familiar with
the operation of your particular
powerplants and will have a good
feel for whether full torque can or
cannot be reached because of ITT
constraints. In the C90GT-series,
in the Blackhawk-modified C90
and E90 models, as well as in -52,
or -61-powered members of the
200-series, ITT is never a limiting
factor if the engine is performing
correctly. It cannot get high or hot
enough for takeoff power ever to be
limited! (Well, maybe in the summer
departing from La Paz, Bolivia, with
an elevation of 13,325 feet.) On
the other hand, the old A90, B90,
and C90s powered by the -20 or
-20A versions of the PT6 rarely can
reach maximum torque, even at Sea
Level, when the OAT is hot. Similarly, it does not take much elevation and temperature increases before the 300-series will run into ITT constraints.
“Golly, Tom! It sounds like it’s going to take an eternity to set takeoff power!” Yes, it probably does sound like that, but truly it does not. Of course, if we are going “by the book,” we set takeoff power before
brake release anyway so how long
it takes is immaterial. But doing
the more common rolling takeoff
– on a comfortably long runway –
the technique I am teaching can
be used and yet full power can be
easily attained by the time the
airspeed reads 40 knots. It may be
hard to believe, but it’s true. (Watch
some of the videos on the YouTube
King Air Academy channel and you
will see for yourself.) We only go
quite slowly until the props are
together at 1,500 RPM, then faster
and with a small pause as the props
hit governing speed, and then very
rapidly to target torque or ITT.
As I stated, advancing the power levers side-by-side almost never gives equal power. But there are times when we may intentionally want different left and right power. Due to the natural left-turning tendency caused by the clockwise- rotating props, some pilots prefer to have slightly higher power on the left than the right side to combat that tendency without using as much rudder. In a string crosswind,
APRIL 2018
also, leading with the upwind engine is quite common and effective. However, my suggestion is to create the torque split with the power levers only after you have used them to smoothly get the propeller speeds matched at the takeoff setting.
Any pilot who spends lots of time with one particular airplane will learn, on a trial-and-error basis, how to best advance power for takeoff and achieve the straight and smooth roll that he or she desires. The technique that I am advocating here will permit you to get in the cockpit of any PT6-powered twin and make your rst takeoff power application as nice as your hundredth! KA
King Air expert Tom Clements has been ying 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 editor@blonigen.net
KING AIR MAGAZINE • 17
CREDIT DAN MOORE VMG LLC