alowishus wrote: ↑
Mon Jul 29, 2019 6:20 am
My hoverglide used to make a kind of groaning sound
. What's the explanation for that?
This is pretty normal for many wings, especially for the lower aspect ones.
As they can easily ride "semistalled", meaning at a very high angle of attack (a lot higher than the high aspect wings), without suddenly loosing all lift (full stall), but only losing a tad of lift at parts of the wing, but still riding.
When doing so (same goes for airplanes), there will be generated loads of turbulence and eddies at (and after) the trailing edge, and also tip vortices, one can almost see this in OzBungy's post with the gif animation.
In many scenarios, low frequency resonance will occur in this turbulence - meaning a deep groaning or humming sound.
It can be so pronounced that you can feel it as a vibration in your feet, easily
This can be enhanced a lot, as if you can hear the sound, you will feel it a lot more than it really is - human nature
I once thought I had a "faulty" wing, the first time I got one that "groaned" ha haa
But found out, it was me not riding "perfectly" - as soon as I got more experience, and rode the wing more, it magically dissapeared.
If this sound comes, you are riding too slow or with too much pressure on your rear foot, so easy to stop.
But it will very often happen when doing tight carves and you push too much.
Still, with time you will avoid this, as your body will find the precise limit so this does not happen anymore.
Having said that, there is no problems in riding like this, apart from being very draggy and close to a full stall.
Being able to ride semi-stalled like this is the very reason we use low aspect wings in waves so you can push the wing more in turns, also "over" the limit and still fly, apart from their faster turning of course.