Private Pilot Flight Training and Instruction
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Opinion On Trim
Trimming the airplane is something that comes with practice.
Like many others have said here, the best way to learn is to
get the airplane relatively stabilized where you want it (climb,
cruise, or decent) and trim the forces off. The best way to get
it right on is when you think you've got it close, simply let
go of the yoke. If the nose comes up or goes down, feed in a
little more trim in the right direction. You should eventually
be able to trim the airplane to be rock steady in any flight
condition (smooth air assumed:)). In fact, you know the trim
wheel on the 172 has little bumps on it just for grip? You should
get to the point where moving the trim wheel one bump in either
direction makes a noticeable difference to the trim.
I tend to be very active with the trim. In fact, I usually retrim
for nearly everything I'm doing if I'm going to be doing it for
more than a couple of minutes. For example, on climbout, I trim
for the climb airspeed and let the airplane fly the climb. In
cruise, I do the same. Also on approach, I retrim for each configuration
to give me the decent rate I'm looking for. In this way, I'm
only ever maneuvering the airplane away from the trimmed condition.
In other words, on approach, I don't have to "fly"
the airplane for the approach because the trim is taking that
workload. That allows me to concentrate on making the correct
turns, setting up the approach, watching out for traffic, configuring
the airplane, watching my decent rate, all without having to
manhandle the yoke. If I need more or less decent rate, I just
move the trim a hair.
The trim on the Piper Cub is a great little arrangement that
uses a winding handle like a car window. It takes quite a
few turns to trim from a climb to level flight, etc. but it also
allows you to make really fine adjustments. In fact, when in
the glide for approach, I may make adjustments to the trim that
are all of about 1/8th of a turn or even less.
Shawn
Trim Opinion
My instructor recommended the following and it works for me;-)
--First NEVER fly the plane with trim wheel, always establish
your attitude (level, climb or descend) with Yoke and power
first.
--When you're stable trim off heavy yoke pressure first and resettle
--Then fine trim until you just have your hand on the yoke but
you aren't inputting any effort at all.
--Let go for a second or two and check and check that it doesn't
climb or descend is the final proof.
--Retrim for every change in attitude. I got to practice this
in the circuit under the lashing tongue of my instructor... Trim
for climb out before and after raising the flaps, trim on crosswind
after leveling, trim after every flap setting and throttle setting
on downwind, base and final. You really get the hang of it then
I can tell you!
Gene's addendum:
Should you ever be in a situation where the elevator is jammed
and will not move, you should be aware that this causes the movement
of the trim to give reverse effects in so far as directing the
nose up or down.
Trim Opinion
Trimming takes some practice but once mastered will make
every aspect of your flying easier. First thing is you can't
trim the plane until it is where you want it to be. If it's climbing
you can't just throw in nose down trim, that would be trying
to fly the plane with trim and even though that's not that uncommon,
it won't work. You have to hold the plane in whatever attitude
you are trying to hold, let the plane settle up, determine whether
you are pushing/pulling on the yoke and then trim those forces
off. Of course if the forces are excessive trim most of it away,
wait for the plane to settle and then finish trimming. The test
is being able to let go of the plane at any time and the plane
is still doing what it was doing before you let it go. Students
never seem to see the importance of trimmed, hands-off flight
until they have to either triangulate their position during a
lost procedure or divert to an airport other than the one flight
planned. Trying to fold and unfold those damn sectionals without
being able to take your hands off the yoke can be a handful.
On my private checkride the DE expected me to let go of the yoke,
check for traffic, draw and compute to my diversion, check for
traffic, maintain a shallow turn as I held altitude and check
for traffic.
Stephen Ames
Written by Gene Whitt
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