Aerodynamics of carrying water

In article et,
"Gene Whitt" wrote:

Thanks everyone. Now for a 'yes' or 'no' answer to my follow-up
question.

Does the addition of weight have the same effect on airplanes with power off
and prop stopped as on gliders but at a less efficient level.?

Of course.

Until you get up to Mach effects, at least.

--
Bruce | 41.1670S | \ spoken | -+-
Hoult | 174.8263E | /\ here. | ----------O----------

Jim Kelly wrote:
Thermalling stores energy in the glider, but thermals stop at
cloud base.

What do you call all that rising air in the cloud?


Jack

The answer contains too many "if"-s

You have to understand, that gliders are in certain sense unique aircrafts.
Non-lifting parts give miniscule amounts of the glider drag (around 10%).
That is very different from other aircrafts (C-172 for example). As speed
increases (due to the higher wing loading), higher non-lifting drag in
motored aircrafts cancels most of the effect of reduced AOA. Provided that
such even excists with wings optimised for absolutely different flying.


Regards,
Kaido


"Gene Whitt" wrote in message
nk.net...
Thanks everyone. Now for a 'yes' or 'no' answer to my follow-up
question.

Does the addition of weight have the same effect on airplanes with power
off and prop stopped as on gliders but at a less efficient level.?

Gene
Aside: I once dove a C-150 to 120 mph before stopped prop
would start the engine,

I once gave a presentation on "speeds to fly when the engine quits" to
a power flying club. Not one person there had any idea that weight and
wind would be a factor but they could all quote the best glide speed
from the POH.

Did you know a DC-10 has a glide ratio nearly as good (bad) as a 2-33.
They get over 20:1 but it's at over 200kts.


Andy

iPilot wrote:
Does the addition of weight have the same effect on airplanes with power
off and prop stopped as on gliders but at a less efficient level.?


The answer contains too many "if"-s

You have to understand, that gliders are in certain sense unique aircrafts.
Non-lifting parts give miniscule amounts of the glider drag (around 10%).
That is very different from other aircrafts (C-172 for example). As speed
increases (due to the higher wing loading), higher non-lifting drag in
motored aircrafts cancels most of the effect of reduced AOA. Provided that
such even excists with wings optimised for absolutely different flying.

For the same AOA, the percentages of drag from lifting and non-lifting
parts will be the same, so we can confidently adjust the polar of an
airplane due to weight changes just as we do for the glider. There
aren't any basic aerodynamic differences between a good glider and a bad
glider.

--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

In article .com,
"Andy" wrote:

Did you know a DC-10 has a glide ratio nearly as good (bad) as a 2-33.
They get over 20:1 but it's at over 200kts.

Yes. Fuel is the major cost of long distance airlines. They save fuel
by reducing drag, which means getting the best possible cruise L/D.

--
Bruce | 41.1670S | \ spoken | -+-
Hoult | 174.8263E | /\ here. | ----------O----------

What do you call all that rising air in the cloud?
Jack


:-) Now, I can only afford to change words - not add words . .
.. so I'll try and get away with this modification (!):

Thermalling stores energy in the glider, but gliders stop at
cloud base. Water carried needs to be lifted too, thus more
energy can be harnessed.

Jim Kelly (ducking for cover . . .)

. . . you could keep your student enticed with stories of shear
wave . . . or cloud flying in UK . . . in the next lessons!

Y'all,
Many thanks for explanations that seemed to mean 'yes!'
Personal email from Pete started something. He found
my three million word web site interesting. I also tell
how I won WWII as a corporal on Tinian.
www.whittsflying.com
Gene Whitt

Andy wrote:

Did you know a DC-10 has a glide ratio nearly as good (bad) as a 2-33.
They get over 20:1 but it's at over 200kts.

Cite?


Jack

In article ,
Jack wrote:

Andy wrote:

Did you know a DC-10 has a glide ratio nearly as good (bad) as a 2-33.
They get over 20:1 but it's at over 200kts.

Cite?

Don't know about the DC-10, but the ancient 707 was about 19:1.

--
Bruce | 41.1670S | \ spoken | -+-
Hoult | 174.8263E | /\ here. | ----------O----------