Reflex wings for dummies (yes including you Dell)

Firstly... yes I know the audio is once again not the best... it’s not about being a great video maker it’s about the content! Adjust your volume settings both on the device hardware AND in the YouTube app. If you can’t work it out then don’t blame me!

This video is an initial attempt to get the message across about why a reflex wing is positively pitch stable and returns to its trimmed position when displaced by an outside influence as well as why a conventional wing is naturally unstable and therefore divergent if not actively flown. Ultimately the pendular effect tends to resolve things however conventional aerofoils are more inclined to collapse before the pendular action can restore matters in more active conditions.

For further information there is still some useful information that can be found on the Glenn Research Centre NASA pages although this is unfortunately rather dumbed down from the info that used to be available. Researching “reflex wing stability” via Google can still lead to some excellent theses giving good further reading.

One further thing... I mentioned incidence as being the angle between the chord line and the pilot. That really doesn’t say anything, my apologies as I was thinking on my feet as I went along! On an aircraft the incidence is the angle between the chord line and a suitable datum on the fuselage such as a line going from front to back. That datum line moves with the aircraft as it pitches. It just defines the angle the wing is set on the craft whereas angle of attack (alpha) is the angle between the chord line and the oncoming (relative) airflow. For our craft I would consider a suitable datum for the incidence of the wing to be measured is between the chord line and a line straight out in front of the pilot (that is reference to the pilot and not the ground!). In our airsport we have one unusual aspect in that our wing can pivot in flight around the wing attachment so the incidence of our wing is much more able to change in flight which then is usually followed by a change in angle of attack.