DG Differences...

On Apr 16, 4:23*pm, "noel.wade" wrote:
On Apr 16, 8:45*am, JS wrote:

*I believe that Walt Rogers did

his first 1000 km flight in his DG-300.

* Confirmed. I was his crew, but flew a 500 O/R in my LS-6 (later
owned by Jim D, Boulder City, NV) first. We are an inbred bunch.
Noel, I'm surprised you didn't snap up AS-W20 "SW" or the 20C that
recently sold.
Jim

Jim -

My raise at work has been held up, so I don't quite yet have the cash
on hand to make an instant-deal. *I've got a commitment from my
Banker / Loan-Officer (who's a pilot and whom I have a good
relationship with), and the only open question really is what to do
about the $10k I still owe on my Russia AC-4. :-/

But in the next 1 - 2 weeks I should be ready to pounce! ;-)

--Noel

I am not familar with the 202, but as someone who flew standard class
for almost 10 years (LS4) and now flying a flapped ship (ASW27) I can
tell you that I love the flaps and that flaps indeed have advantage
for serious XC flying or competitions in moderate to strong
conditions, however it should not be your main decision point, and if
you are going to fly consrvative XC in only moderate conditions or
compete in spots class, the flaps will do very little to your bottom
line, while they will certainly add to your work load, especially
during take off and landings. Landing flaps are nice, but in 10 years
of many outlandings I never had a situation which I wished I had
landing flaps. So boottom line, take everything into account and go
for the glider you like best, in better condition, has better trailer,
better resale value, easier to rig an maintain and to get service, has
better reputation, more popular etc etc. and keep the flap somehwre
lower in your evaluation list. And last, you should completly ignore
facts such as how many kms or which contest or record someone won in
one ship or another, it is 99% combination of pilot,weather, location
and timing. Flaps and L/D are only a small factor.

Ramy

Thanks All,

On the flaps vs. no-flaps argument, I guess it would be best to use a
hypothetical situation:

Imagine you have cloudbases that are 3000' to 4000' AGL.
Terrain is somewhat mountainous, but the cloudbases rise with the
terrain (20 miles east of the airport you might have 7000' - 8000' MSL
bases over a 5000' MSL mountain).
The lift is maxing out between 4 knots and 6 knots, with a lot of 2 to
3 knotters mixed in.
The Cu are 4 - 6 miles apart.
Winds are 5 - 10 knots, with the best soaring areas downwind from your
home field (so you face a mild upwind glide home).
Your total "window" for soaring is a 5 hour period during the day when
conditions are going to be generating lift.
The lift is workable from 1000' AGL to cloudbase, but staying within
1500' of cloubase seems much more comfortable.

This is a pretty typical "decent" soaring day in Western Washington.

So the question for you flapped pilots is: Would you be pushing your
speed up enough in this situation to actually be using your flaps?

....Assume you're trying to do good cross-country flying - not super-
agressive contest-like flying, but also not just puttering around
within 15 miles of the airport either.

Thanks!

--Noel

On Apr 16, 5:50*pm, "noel.wade" wrote:
Thanks All,

On the flaps vs. no-flaps argument, I guess it would be best to use a
hypothetical situation:

Imagine you have cloudbases that are 3000' to 4000' AGL.
Terrain is somewhat mountainous, but the cloudbases rise with the
terrain (20 miles east of the airport you might have 7000' - 8000' MSL
bases over a 5000' MSL mountain).
The lift is maxing out between 4 knots and 6 knots, with a lot of 2 to
3 knotters mixed in.
The Cu are 4 - 6 miles apart.
Winds are 5 - 10 knots, with the best soaring areas downwind from your
home field (so you face a mild upwind glide home).
Your total "window" for soaring is a 5 hour period during the day when
conditions are going to be generating lift.
The lift is workable from 1000' AGL to cloudbase, but staying within
1500' of cloubase seems much more comfortable.

This is a pretty typical "decent" soaring day in Western Washington.

So the question for you flapped pilots is: *Would you be pushing your
speed up enough in this situation to actually be using your flaps?

...Assume you're trying to do good cross-country flying - not super-
agressive contest-like flying, but also not just puttering around
within 15 miles of the airport either.

Thanks!

--Noel

This is the typical soaring conditions at my home area. We always use
the flaps, no matter how strong or weak the soaring conditions are,
since you need to change from thermaling to cruising flap. In a flap
ship you must change flaps, otherwise your performance will probably
be worse then a standard ship. If you want to know how the glider
performance will impact your results, just look at the handicap
difference between the gliders you consider and can assume that your
speed and/or distance will roughly differ by this handicap, typically
in the 5% range.

Ramy

I think you are over-analyzing this issue. The difference between flaps
and no flaps is so small that you won't notice it. What difference does
it make if a recreational flight is 300 km (no flaps) rather than 315 km
(flaps)?

In contrast, you will notice if your glider is hard to rig, has a poor
trailer, or isn't comfortable or fun to fly. Those are the things that
you should be focusing on.



noel.wade wrote:
Thanks All,

On the flaps vs. no-flaps argument, I guess it would be best to use a
hypothetical situation:

Imagine you have cloudbases that are 3000' to 4000' AGL.
Terrain is somewhat mountainous, but the cloudbases rise with the
terrain (20 miles east of the airport you might have 7000' - 8000' MSL
bases over a 5000' MSL mountain).
The lift is maxing out between 4 knots and 6 knots, with a lot of 2 to
3 knotters mixed in.
The Cu are 4 - 6 miles apart.
Winds are 5 - 10 knots, with the best soaring areas downwind from your
home field (so you face a mild upwind glide home).
Your total "window" for soaring is a 5 hour period during the day when
conditions are going to be generating lift.
The lift is workable from 1000' AGL to cloudbase, but staying within
1500' of cloubase seems much more comfortable.

This is a pretty typical "decent" soaring day in Western Washington.

So the question for you flapped pilots is: Would you be pushing your
speed up enough in this situation to actually be using your flaps?

...Assume you're trying to do good cross-country flying - not super-
agressive contest-like flying, but also not just puttering around
within 15 miles of the airport either.

Thanks!

--Noel

Greg Arnold wrote:
I think you are over-analyzing this issue. The difference between flaps
and no flaps is so small that you won't notice it. What difference does
it make if a recreational flight is 300 km (no flaps) rather than 315 km
(flaps)?

In contrast, you will notice if your glider is hard to rig, has a poor
trailer, or isn't comfortable or fun to fly. Those are the things that
you should be focusing on.

Amen, Brother Arnold! Especially in the conditions Noel describes,
speeds will be low, and flaps will make an insignificant difference in
the soaring performance.

Where flaps can make an important difference is in landing. You will be
able to put an ASW 20 into a shorter field than an Standard Class
glider. The landing flaps (60 degree deflection on the original 20, 40
degree deflection on the B and C models) let you arrive more steeply,
more slowly, and stop more quickly than an unflapped glider of similar
soaring performance.

My experience in Western Washington (2 flights) isn't enough to advise
you about field size!

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

Just to assuage everyone's concerns: I am very familiar with the
importance of a trailer and good rigging. This is why I'm especially
keen on automatic hookups and something like a Cobra trailer. I've
SEEN the difference a trailer makes when I help certain people at my
field rig (even just in the difference between bracing / tie-down
methods in similar trailers can have a big impact), and understand
this point very well.

As for flapped performance: The reason I talk about speed is because
if you look at things like Idaflieg test data, the polar of say a
DG-300 and an ASW-20 are nearly identical at similar wing-loadings, at
about 55 knots and below. Above that the ASW-20 starts winning out by
a small margin to around 75 knots, and then above that the negative
flap settings seem to make a pretty noticeable difference in the polar
and the ASW-20 is the clear winner.

As another example: Look at the Johnson review of the ASW-20. Check
out the composite polar diagrams. Looks like you have to get up over
75 knots before the negative flaps really start becoming superior to
the 0-degree flap position.

This is why I'm phrasing things in terms of speed or XC distance/
aggressiveness. The "climb" flaps of the ASW-20 are certainly
superior (in small but noticeable ways) to the standard-class ships of
the late-70's. But the 80's standard-class ships seem to be equal to
the ASW-20 in terms of minimum sink and low-speed polar curves. Newer
airfoils seem to have a smaller "knee" in the polar curve at middling
speeds, but its still there for any standard-class ship. However its
the upper end of the polar that really seems to be the difference
(ignoring the landing-flaps deal). Am I off-base here?

*shrug* My longest XC flight so far is ~130 miles total distance-over-
ground on a 4 hour flight that didn't actually get too far from home-
base (low clouds in the mountains kept me from going where I wanted).
I'd like to be able to push a little harder to get from cloud to cloud
and cover more ground - but I'm not eager to risk landouts like one or
two "aggressive" pilots in my club who get low a lot, and land out a
good 3 - 4 times every year.

My XC experience to date is in a Russia AC-4 so I'm not sure how huge
of a jump its going to be when I move up to a 40:1 ship; maybe that
increase in performance alone will be enough to make me feel better
about cloud-hopping at slightly higher than best-L/D speed, or
stretching out a bit further to find lift.

I just don't have the experience to know if I'm really going to be
jonesing for that flap handle after I fly a standard-class ship for a
year... I thrive on challenges and new experiences - being bored with
my ship would be a nightmare!

Take care,

--Noel
P.S. Brad - I already looked at an Apis kit. Price of the Euro has
killed that for me! :-P

On Apr 16, 10:23*pm, "noel.wade" wrote:
Just to assuage everyone's concerns: *I am very familiar with the
importance of a trailer and good rigging. *This is why I'm especially
keen on automatic hookups and something like a Cobra trailer. *I've
SEEN the difference a trailer makes when I help certain people at my
field rig (even just in the difference between bracing / tie-down
methods in similar trailers can have a big impact), and understand
this point very well.

As for flapped performance: *The reason I talk about speed is because
if you look at things like Idaflieg test data, the polar of say a
DG-300 and an ASW-20 are nearly identical at similar wing-loadings, at
about 55 knots and below. *Above that the ASW-20 starts winning out by
a small margin to around 75 knots, and then above that the negative
flap settings seem to make a pretty noticeable difference in the polar
and the ASW-20 is the clear winner.

As another example: *Look at the Johnson review of the ASW-20. *Check
out the composite polar diagrams. *Looks like you have to get up over
75 knots before the negative flaps really start becoming superior to
the 0-degree flap position.

This is why I'm phrasing things in terms of speed or XC distance/
aggressiveness. *The "climb" flaps of the ASW-20 are certainly
superior (in small but noticeable ways) to the standard-class ships of
the late-70's. *But the 80's standard-class ships seem to be equal to
the ASW-20 in terms of minimum sink and low-speed polar curves. *Newer
airfoils seem to have a smaller "knee" in the polar curve at middling
speeds, but its still there for any standard-class ship. *However its
the upper end of the polar that really seems to be the difference
(ignoring the landing-flaps deal). *Am I off-base here?

*shrug* *My longest XC flight so far is ~130 miles total distance-over-
ground on a 4 hour flight that didn't actually get too far from home-
base (low clouds in the mountains kept me from going where I wanted).
I'd like to be able to push a little harder to get from cloud to cloud
and cover more ground - but I'm not eager to risk landouts like one or
two "aggressive" pilots in my club who get low a lot, and land out a
good 3 - 4 times every year.

My XC experience to date is in a Russia AC-4 so I'm not sure how huge
of a jump its going to be when I move up to a 40:1 ship; maybe that
increase in performance alone will be enough to make me feel better
about cloud-hopping at slightly higher than best-L/D speed, or
stretching out a bit further to find lift.

I just don't have the experience to know if I'm really going to be
jonesing for that flap handle after I fly a standard-class ship for a
year... *I thrive on challenges and new experiences - being bored with
my ship would be a nightmare!

Take care,

--Noel
P.S. *Brad - I already looked at an Apis kit. *Price of the Euro has
killed that for me! :-P

We understand your reasons. Hopefully you uderstand what we are all
saying, flaps or no flaps will not make much of a differece to your XC
results, as handicap shows. Almost everything else matter much more to
your overall experience. Either the 300 or the 20 will perform much
better than your Russia, and will look much better as well.

Ramy

I was looking for an ASW20 and ended up buying a DG300, for different
reasons: the easy rigging as you mention, the amazing visibility
(it's sooo cool), the price - with the restrictions introduced in
europe prices went down significantly, the good condition of the one i
found, the reports from friends on how much pleasure it is to fly one.

For an ASW20 the only version i could find at the time in the same
price range was the F, and i was told this is not exactly the same as
a B or C. I was told the F demands more attention and experience from
the pilot as it has a bigger tendency to stall when not flown
properly. Considering my experience i feel better now knowing my DG
would never treat me in such a way... and i give her the same caring
treatment in return.

If i would find an ASW20 and a DG300 on the same price range, i would
pick the one in best condition and better equipped. I got an LX5000, a
FLARM, a Komet trailer and a nice interior which i now value a lot.
Seriously... you think you would get bored with a non-flapped 15m ship
that has 40+ glide ratio?

Ricardo

On Apr 17, 7:23 am, "noel.wade" wrote:
Just to assuage everyone's concerns: I am very familiar with the
importance of a trailer and good rigging. This is why I'm especially
keen on automatic hookups and something like a Cobra trailer. I've
SEEN the difference a trailer makes when I help certain people at my
field rig (even just in the difference between bracing / tie-down
methods in similar trailers can have a big impact), and understand
this point very well.

As for flapped performance: The reason I talk about speed is because
if you look at things like Idaflieg test data, the polar of say a
DG-300 and an ASW-20 are nearly identical at similar wing-loadings, at
about 55 knots and below. Above that the ASW-20 starts winning out by
a small margin to around 75 knots, and then above that the negative
flap settings seem to make a pretty noticeable difference in the polar
and the ASW-20 is the clear winner.

As another example: Look at the Johnson review of the ASW-20. Check
out the composite polar diagrams. Looks like you have to get up over
75 knots before the negative flaps really start becoming superior to
the 0-degree flap position.

This is why I'm phrasing things in terms of speed or XC distance/
aggressiveness. The "climb" flaps of the ASW-20 are certainly
superior (in small but noticeable ways) to the standard-class ships of
the late-70's. But the 80's standard-class ships seem to be equal to
the ASW-20 in terms of minimum sink and low-speed polar curves. Newer
airfoils seem to have a smaller "knee" in the polar curve at middling
speeds, but its still there for any standard-class ship. However its
the upper end of the polar that really seems to be the difference
(ignoring the landing-flaps deal). Am I off-base here?

*shrug* My longest XC flight so far is ~130 miles total distance-over-
ground on a 4 hour flight that didn't actually get too far from home-
base (low clouds in the mountains kept me from going where I wanted).
I'd like to be able to push a little harder to get from cloud to cloud
and cover more ground - but I'm not eager to risk landouts like one or
two "aggressive" pilots in my club who get low a lot, and land out a
good 3 - 4 times every year.

My XC experience to date is in a Russia AC-4 so I'm not sure how huge
of a jump its going to be when I move up to a 40:1 ship; maybe that
increase in performance alone will be enough to make me feel better
about cloud-hopping at slightly higher than best-L/D speed, or
stretching out a bit further to find lift.

I just don't have the experience to know if I'm really going to be
jonesing for that flap handle after I fly a standard-class ship for a
year... I thrive on challenges and new experiences - being bored with
my ship would be a nightmare!

Take care,

--Noel
P.S. Brad - I already looked at an Apis kit. Price of the Euro has
killed that for me! :-P

noel.wade wrote:

As for flapped performance: The reason I talk about speed is because
if you look at things like Idaflieg test data, the polar of say a
DG-300 and an ASW-20 are nearly identical at similar wing-loadings, at
about 55 knots and below. Above that the ASW-20 starts winning out by
a small margin to around 75 knots, and then above that the negative
flap settings seem to make a pretty noticeable difference in the polar
and the ASW-20 is the clear winner.

I typically cruise at 70-80 knots in Eastern Washington conditions, and
that's in a 50:1, 18 meter, 8.3 pound wing loading glider. With your
experience and Western Washington conditions, I think it will be a rare
day when you will want to cruise at even 70 knots in 15 meter glider,
flapped or not.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

On Wed, 16 Apr 2008 22:23:24 -0700, noel.wade wrote:

This is why I'm phrasing things in terms of speed or XC distance/
aggressiveness. The "climb" flaps of the ASW-20 are certainly
superior (in small but noticeable ways) to the standard-class ships of
the late-70's.

As a some-time 20 driver I found that I almost never used thermal flap.
The glider felt a lot livelier and climbed almost as well in zero flap.
I only used thermal flap when digging myself out of a hole in very weak
lift. I've been told that a 20 spins more easily in thermal flap though
didn't experience that.

If it helps any, read what Andreas Maurer had to say about flying the 20.
I found it very helpful. Mine was an early version with the Jesus flap
setting. A copy of his notes is he

http://www.gregorie.org/gliding/asw2..._handling.html

If you do go for the 20 you'll find that learning to fly a flapped glider
is rather like the experience that somebody who learnt to drive an
automatic car has when converting to a manual gearbox: the mechanics of
using the flaps is easy enough but the business of being in the right
flap setting at all times takes time and practise.


--
martin@ | Martin Gregorie
gregorie. |
org | Zappa fan & glider pilot