C*: Yaw

Mon 01 April 2019
aileron Vertical stabilizer (Photo credit: Wikipedia)

This post is about yaw control. This is also the post for which I did not find many references.

Remember the yaw is the axis controlled by the rudder. The rudder acts as any foil, providing a force dependant of its angle of attack. This angle of attack is function of side slip angle (noted β) and the rudder's deflection.

Basically, the rudder command an effort on the stabilizer, inducing a rotation around the yaw axis. Note that the stabilizer also induce a force on this axis. The stabilizer's force tend reduce sideway slip. This momentum grows with speed.

On the way

The aircraft velocity is high, there is little risks to stall. The goal is to avoid extra drag due to going sideways. When the pilot's rudder is at neutral position, the aircraft must go straight ahead and the pilot should command the sideslip angle. When performing turns, pilot's input to neutral must result coordinated turns (rudder not in neutral position). Yaw control is also used for stabilisation purpose (e.g. yaw damping).

At low altitude

When really close to the ground, roll cannot be used to control airplane's trajectory. The bank angle is limited due to both the ground clearance and the low speed (when near stall, having wings not leveled is not wise). Thus, the rudder is used to control direction.

Normal law

Normal law is used in flight in normal condition. The A320 and the A380 does not act the same way.

  • the A320 adds pilots' input and flight-by-wire (FBW) orders [2]. The FBW system add orders so that with neutral pilot input, it handles yaw damping and coordinates turns
  • on the A380, the pilot's input commands sideslip angle.

Ground law

On the A380, the pilot control the yaw rate [1]. I found no evidence for the A320, thus I assume the FBW system adds no input.

Direct law

[1]source: A380 Briefing For Pilots, march 2006
[2]source: AAIB Bulletin: 8/2008 incident report

Category: aviation Tagged: C star Flight dynamics yaw

LaTeX makefile updated

Fri 29 March 2019

My default LaTeX makefile evolved. Here is an update:

The makefile looks like:

RERUN='(There is undefined reference|Rerun to get (cross-references|the bars) right)'

    ${LATEX} $<
    @if [ -e $*.bbl ]; then ${BIBTEX} $* && ${LATEX} $< && ${LATEX} $< ; fi
    @if egrep -q $(RERUN) $*.log ; then ${LATEX} $< ; fi

%.aux …

Category: tools Tagged: GNU LaTeX Makefile Writing how to tools

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Back online

Mon 18 February 2019

I've migrated the blog from wordpress to pelican. Static files, quite easy to use.

The migration process went well. The pelican import tool is easy to use and my rst linter highlighted the few errors done by the import tools (mainly empty sections).

There are still few artefacts due to …

Category: tools Tagged: pelican wordpress blog tools

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Seine flooding

Mon 13 June 2016

[caption id="" align="alignright" width="350" class="zemanta-img"]Français : Crue de la Seine à Paris en 1910. Seine, Paris, 1910. (Photo credit: Wikipedia)[/caption]

On this mounth, the Seine decided to flood Paris and its neighborouds, so I took my camera to take pictures. I realised:

I was not alone

[caption id="attachment_2567" align="alignnone" width="250"]image0 TV team …

Category: photography Tagged: Flooding Paris Seine

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GPG key renewal

Tue 02 February 2016

[caption id="" align="alignright" width="75" class="zemanta-img"]English: An example of a standard key used for... standard key (Photo credit: Wikipedia)[/caption]

What happen when a PGP key expire? Obvious answer: you can no longer securely use it. Nevertheless, you may not delete it as you must be able to read your encrypted files.

Basics step that should …

Category: network security Tagged: FAQs Help and Tutorials Mail tools

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awesome global shortcut

Mon 04 January 2016

[caption id="" align="alignright" width="200" class="zemanta-img"]Multimedia keyboard Multimedia keyboard (Photo credit: Wikipedia)[/caption]

The awesome window manager does not provide GUI configuration tool.

Here is a litte how to to provide a feature using global shortcut, illustrated with wolume control.

Defining and identifying the feature and the shortcut

The …

Category: how to Tagged: alsa ArchLinux awesome Configuration file FAQs Help and Tutorials Unix window manager tools

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