WS Aero Angle of Attack: Video

[skydiverek 54]

https://www.youtube.com/watch?v=4BOVi9fQhQw

[kallend 1,621]

Tacks at various angles.

...

The only sure way to survive a canopy collision is not to have one.

[Anachronist 2]

I'm glad to see some people putting together better information and presentations than what is available through "official" skydiving organizations, e.g. USPA etc.

But at the same time I would like to see some analysis of some more complicated aerodynamic principles and processes. The AOA vid is basically what Wikipedia can tell you. Force vectors in static positions just isn't very interesting.

For instance, I don't totally understand what is happening when I'm flying at a slightly higher AOA, then pitch down and reduce AOA, over the next several seconds my glide ratio drops (I pitched down after all) and my airspeed increases, then without any intentional change in body position my glide ratio increases significantly. It is simply because of higher airspeed increasing lift and a gradual reduction in AOA as airspeed increases? Or is it because an acceleration due to pitching down allows an airspeed threshold of sorts to be crossed and flight at a lower AOA but greater glide ratio made possible? Or are those two things really the same thing? Seeing how pitch, AOA, and airspeed change throughout that process would be interesting. It's the dynamic aerodynamic stuff that is most interesting/confusing to me.

[kallend 1,621]

Anachronist

I'm glad to see some people putting together better information and presentations than what is available through "official" skydiving organizations, e.g. USPA etc.

But at the same time I would like to see some analysis of some more complicated aerodynamic principles and processes. The AOA vid is basically what Wikipedia can tell you. Force vectors in static positions just isn't very interesting.

For instance, I don't totally understand what is happening when I'm flying at a slightly higher AOA, then pitch down and reduce AOA, over the next several seconds my glide ratio drops (I pitched down after all) and my airspeed increases, then without any intentional change in body position my glide ratio increases significantly. It is simply because of higher airspeed increasing lift and a gradual reduction in AOA as airspeed increases? Or is it because an acceleration due to pitching down allows an airspeed threshold of sorts to be crossed and flight at a lower AOA but greater glide ratio made possible? Or are those two things really the same thing? Seeing how pitch, AOA, and airspeed change throughout that process would be interesting. It's the dynamic aerodynamic stuff that is most interesting/confusing to me.

SOunds like a phugoid.

...

The only sure way to survive a canopy collision is not to have one.

[Anachronist 2]

That is my best guess as far as initiation, but there is no oscillation, just steady acceleration and increase in glide until stable. But who knows, phugoid is described in powered aircraft, maybe the unpowered version is what I described. But is it really "phugoid" or some other thing going on with a really inefficient aircraft that lacks a normal "tail" and rigidity? It may be that phugoid is initiated and then dampened/arrested due to the nature of a person in a WS rather than a rigid structure with a well placed CG? On a side note, I'd love the know where a human CG actually is, and I'm sure it is variable. That's why I'd love to see some better vids covering dynamic stuff

[johnmatrix 21]

Anachronist

I'd love the know where a human CG actually is, and I'm sure it is variable.

It would vary with the body shape of the jumper.
I am no expert but I feel like a tall muscular person would have a natural advantage in performance flying, with bulk around the shoulders and chest and comparitively less around the waist it would move the CG further to the front of the wing, allowing for more forward speed at a given AoA.

Part of the reason I am trying to get fitter and eat less burgers.

[skow 6]

First the mass, then the shape!!!

So you need 'em burgers

[johnmatrix 21]

Best news I've had all day. Thanks for posting.

[RTB 0]

johnmatrix

Best news I've had all day. Thanks for posting.

No you don't need burgers, you need less carbs and more training
Will we see you in Norway this summer?

[johnmatrix 21]

Unfortunately I don't think so at this stage, but hopefully next year. :)
At least I will save money on Norwegian burgers.

[kleggo 138]

johnmatrix

***I'd love the know where a human CG actually is, and I'm sure it is variable.

It would vary with the body shape of the jumper.
I am no expert but I feel like a tall muscular person would have a natural advantage in performance flying, with bulk around the shoulders and chest and comparitively less around the waist it would move the CG further to the front of the wing, allowing for more forward speed at a given AoA.



Maybe, but their is a certain national champion sponsored by wicked wingsuits who does not fit the "tall muscular person" description........

I guess it all depends on the definition of "performance flying".

cheers
more salad, less meat.