Wing Loading / climb rate

On Monday, February 13, 2017 at 8:50:39 PM UTC+3, Dan Marotta wrote:
If the lifting force exactly matched the weight of the glider then, in
still air, wouldn't the glider not lose altitude? Or are you saying
that the sink rate of the glider is cause by drag?

On 2/13/2017 6:46 AM, Tango Whisky wrote:
Le lundi 13 février 2017 04:52:04 UTC+1, Jim a écrit :
Yes, I have enjoyed slower-flying thermal-working too. It's lots of fun.

My curiosity about wing loading and climb rate really is limited to non-thermalling, non-turning flight. I was wondering about the possible relationship of wing loading to lifting force. Likely an unrealistic circumstance in actual flying though. Just a curiosity.
Well, on a good soaring day, about 70-80% of the flight is non-thermalling, non-turning flight.
And the lifting force always matches the weight of the glider, regardless of wing loading.

As I'm sure you know, lift = weight is exactly true for a powered aircraft in straight and level flight.

It's only an approximation for a glider, where in fact lift plus drag together exactly equal weight. But as the lift is typically 40 - 60 times the drag we usually take a shortcut and ignore that.

In a glider with airbrakes deployed and in a steady speed 45 degree dive lift and drag are equal and both 70.71% of the weight. But that's not how we fly when trying to maximize performance.

That's what I was thinking. Ignore the small part of the sum. Thanks,
nice refresher!

On 2/13/2017 12:01 PM, Bruce Hoult wrote:
On Monday, February 13, 2017 at 8:50:39 PM UTC+3, Dan Marotta wrote:
If the lifting force exactly matched the weight of the glider then, in
still air, wouldn't the glider not lose altitude? Or are you saying
that the sink rate of the glider is cause by drag?

On 2/13/2017 6:46 AM, Tango Whisky wrote:
Le lundi 13 février 2017 04:52:04 UTC+1, Jim a écrit :
Yes, I have enjoyed slower-flying thermal-working too. It's lots of fun.

My curiosity about wing loading and climb rate really is limited to non-thermalling, non-turning flight. I was wondering about the possible relationship of wing loading to lifting force. Likely an unrealistic circumstance in actual flying though. Just a curiosity.
Well, on a good soaring day, about 70-80% of the flight is non-thermalling, non-turning flight.
And the lifting force always matches the weight of the glider, regardless of wing loading.
As I'm sure you know, lift = weight is exactly true for a powered aircraft in straight and level flight.

It's only an approximation for a glider, where in fact lift plus drag together exactly equal weight. But as the lift is typically 40 - 60 times the drag we usually take a shortcut and ignore that.

In a glider with airbrakes deployed and in a steady speed 45 degree dive lift and drag are equal and both 70.71% of the weight. But that's not how we fly when trying to maximize performance.

--
Dan, 5J