Uploaded September 2021 | Updated September 2026, 1 week ago

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Trim means the aircraft isn't rotating, and it is holding altitude.

Jump Ahead:
00:00 Intro
00:42 Trim Means Neutral Moment (No Torque)
01:48 Trim Also Requires Balanced Lift
03:28 If We Aren't Rotating, How Do We Follow the Curve?
05:53 Out Of Trim Means It Wants To Rotate
08:29 What Happens If We Increase Airspeed?
10:11 We Must Lower The Angle Of Attack To Reduce Lift
12:22 But Reducing Angle Of Attack Messed Up the Downforce On the Tail
13:09 On a Commercial Jet, We Adjust the Angle Of Attack Of the Entire Tail
13:40 Fighter Jets Have All-Moving Tails Anyway
13:54 Light Planes Use Trim-Tabs
15:19 Summary
Trim means the aircraft will hold its current Angle of Attack.
We say it has zero moment, but REALLY that means steady angle of attack.
Wind (or curvature) may cause the angle of attack to change, and trim means it fixes itself.

Trim means the aircraft is neither climbing nor descending.
That means lift balances weight.

The pilot must adjust the trim.

Three main ways to trim (in pitch).
Adjustable tail angle of attack (like a commercial jet)
Fully actuated horizontal tail (like a fighter jet)
Trim-tabs that adjust the elevator (like a light aircraft)

Source Material:
"An overview of the Elevators and Trim in aircraft. How pilots control the pitch attitude."
by Wolfie6020
youtu.be/A11dq5CgMI8

"F-22 Raptor Control Surface Test"
by BismarckMandanBlog
youtu.be/jSWgXz994XE

"Understanding Trim"
by Jeff Schaefer
youtu.be/GL_US54xZ9c