I need help Comparing and Calculating final glide performance

On Nov 1, 1:41*pm, Udo wrote:
The 57 kt versus 50 kt can be explained by the fact, that the second
glider was a little higher before it went through the same point in
space as glider A. *Glider A had a wingloading of 8 lb/ft^2 Glider B
8.3 lb/ft^2. It was heavier by 3.6%

Were they the same glider model? It's not clear what point you are
trying to make or understand. Two gliders flying the same distance at
different speeds will have different performance, particularly if they
are not the same glider type and they fly even slightly different
courses. The difference in starting speed between the two gliders
doesn't matter. The only things that really matter in this example are
the cruise speeds and the difference between starting energy and
finishing energy - and of course the altitude loss over the prescribed
distance.

I'm dying to know the question behind your question. Is there a lesson
in this for all of us?

9B

On Nov 1, 2:08*pm, Andy wrote:
On Nov 1, 1:41*pm, Udo wrote:

The 57 kt versus 50 kt can be explained by the fact, that the second
glider was a little higher before it went through the same point in
space as glider A. *Glider A had a wingloading of 8 lb/ft^2 Glider B
8.3 lb/ft^2. It was heavier by 3.6%

Were they the same glider model? *It's not clear what point you are
trying to make or understand. *Two gliders flying the same distance at
different speeds will have different performance, particularly if they
are not the same glider type and they fly even slightly different
courses. The difference in starting speed between the two gliders
doesn't matter. The only things that really matter in this example are
the cruise speeds and the difference between starting energy and
finishing energy - and of course the altitude loss over the prescribed
distance.

I'm dying to know the question behind your question. Is there a lesson
in this for all of us?

9B

The difference in wingloading explains 1 additional L/D point for
Glider B. So you still have only half the expected difference in L/D -
2.2 points versus and expected 3 or 4. My only explanation is that
Glider B must've been better by 5-7% or flew through air that was an
equivalent amount better.

9B

Andy,
It was between an ASW27B and my modifyded HP18.
I have a bit of time to reflect on my past.
If you wish you can review the flight log your self on the Schreder
website.
http://www.soaridaho.com/Schreder/St...03_Seniors.htm
Udo



On Nov 1, 5:17*pm, Andy wrote:
On Nov 1, 2:08*pm, Andy wrote:


On Nov 1, 1:41*pm, Udo wrote:

The 57 kt versus 50 kt can be explained by the fact, that the second
glider was a little higher before it went through the same point in
space as glider A. *Glider A had a wingloading of 8 lb/ft^2 Glider B
8.3 lb/ft^2. It was heavier by 3.6%

Were they the same glider model? *It's not clear what point you are
trying to make or understand. *Two gliders flying the same distance at
different speeds will have different performance, particularly if they
are not the same glider type and they fly even slightly different
courses. The difference in starting speed between the two gliders
doesn't matter. The only things that really matter in this example are
the cruise speeds and the difference between starting energy and
finishing energy - and of course the altitude loss over the prescribed
distance.

I'm dying to know the question behind your question. Is there a lesson
in this for all of us?

9B

The difference in wingloading explains 1 additional L/D point for
Glider B. So you still have only half the expected difference in L/D -
2.2 points versus and expected 3 or 4. My only explanation is that
Glider B must've been better by 5-7% or flew through air that was an
equivalent amount better.

9B- Hide quoted text -

- Show quoted text -

On Nov 1, 4:11*pm, Udo wrote:
Andy,
It was between an ASW27B and my modifyded HP18.
*I have a bit of time to reflect on my past.
If you wish you can review the flight log your self on the Schreder
website.http://www.soaridaho.com/Schreder/St..._Seniors/2003_...
Udo

On Nov 1, 5:17*pm, Andy wrote:



On Nov 1, 2:08*pm, Andy wrote:

On Nov 1, 1:41*pm, Udo wrote:

The 57 kt versus 50 kt can be explained by the fact, that the second
glider was a little higher before it went through the same point in
space as glider A. *Glider A had a wingloading of 8 lb/ft^2 Glider B
8.3 lb/ft^2. It was heavier by 3.6%

Were they the same glider model? *It's not clear what point you are
trying to make or understand. *Two gliders flying the same distance at
different speeds will have different performance, particularly if they
are not the same glider type and they fly even slightly different
courses. The difference in starting speed between the two gliders
doesn't matter. The only things that really matter in this example are
the cruise speeds and the difference between starting energy and
finishing energy - and of course the altitude loss over the prescribed
distance.

I'm dying to know the question behind your question. Is there a lesson
in this for all of us?

9B

The difference in wingloading explains 1 additional L/D point for
Glider B. So you still have only half the expected difference in L/D -
2.2 points versus and expected 3 or 4. My only explanation is that
Glider B must've been better by 5-7% or flew through air that was an
equivalent amount better.

9B- Hide quoted text -

- Show quoted text -

Udo,

I think I have the answer for you. The difference in your loggers
gives you an additional 187 feet of altitude so you actually had 13.4%
more energy to expend to achieve the 9% faster speed. Look at the
altitudes after you each land.

Hi Tim
After careful study here are my revised data points.

The difference is 187 ft when stationary on the ground

After reviewing the altitudes of both gliders at the same finish
line, time stamp 20:26 the difference is 40 ft
.. Glider A dove 40 ft lower at the finish at time stamp 20:22 altitude
131 ft
B finished at the same finish point at 20:02 altitude -16 ft -187 ft
= 171 ft real altitude.

At the start, B has the advantage on the the time mark of 14:00 of
plus 187 ft

Restating the data points
A at point 13:46 had a speed of 52 kt and an altitude of 2333 ft
B at the nearly the same point at 14:00 had aspeed of 62 kt at an
altitued of 2297 ft plus the 187 logger differencial fo a total of
2484
for B a 151 ft advantage

The total advantage for B was 111 ft. ( 151 ft -40 ft) plus carring
10 kt more energy at the start and finishing also with a 5 kt higher
speed
but B also flew faster by 34 seconds.

Udo

Udo,

I think I have the answer for you. *The difference in your loggers
gives you an additional 187 feet of altitude so you actually had 13.4%
more energy to expend to achieve the 9% faster speed. *Look at the
altitudes after you each land.- Hide quoted text -

- Show quoted text -