Lecture.11 - Aircraft Stability and Control AE 1350 Lecture...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
Aircraft Stability and Control AE 1350 Lecture Notes #11
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
We will study What do we mean by aircraft stability and control? Static and Dynamic Stability Longitudinal, lateral and roll stability Necessary Conditions for Longitudinal stability Stability Margin Relaxed Stability Margin
Background image of page 2
A system is said to be stable if it can recover from small disturbances that affect its operation. A cone resting on its base is stable. Unstable Neutrally stable. Assumes new position caused by the disturbance.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
An aircraft is subjected to some disturbance, say a gust, a cross wind or turbulence Unexpected Gust Will it recover automatically, without pilot’s intervention, and resume its original direction of flight? If so, the aircraft is longitudinally stable. Freestream
Background image of page 4
Longitudinal Static Stability Alpha Aircraft is in steady level flight Gust pitches the nose up The initial tendency of the vehicle is to bring the nose down. If so, The aircraft is statically stable. Alpha Time The initial tendency of the vehicle is to bring the nose up. If so, The aircraft is statically unstable.
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Aircraft may be statically unstable, but dynamically stable Longitudinal Stability 3 3.5 4 4.5 5 5.5 6 0 5 10 15 20 25 30 35 Time, in seconds Alpha, in degrees Initial tendency may be to pitch the nose up Statically unstable. Over a long period, vehicle recovers. Dynamically stable.
Background image of page 6
Aircraft may be statically and dynamically stable 3 3.5 4 4.5 5 5.5 6 0 10 20 30 40 Time Alpha Initial tendency and long-term tendency both are to recover from a gust or disturbance Gust pitches nose up
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Aircraft may be dynamically unstable Longitudinal Stability -20 0 20 40 0 10 30 Time, seconds Alpha, Degrees
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 21

Lecture.11 - Aircraft Stability and Control AE 1350 Lecture...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online