DG Differences...

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

Easy decision..................I fly an Aps-13 in just these
conditions and kick ass!

Brad

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

On Wed, 16 Apr 2008 17:50:24 -0700 (PDT), "noel.wade"
wrote:

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?

Noel,

flaps only increase your highspeed performance. The better the
weather, the more advantage a flapped glider will have.

The index values show this pretty well: A flapped glider has up to 7
percent more prformance than a standard class glider, meaning that
your cruise speed is going to be 7 percent faster at best.

Judge yourself if you really need this...


Bye
Andreas

As long as you don't purchase one from Falcon Gauge
there are Chinese made, mine lasted 75 hours
and they like to charge me what ever it takes to
repair it, but will charge you up front $ 350 bucks
Cheers



"noel.wade" wrote in message
...
Hi All,

This is a bit of a loaded question (I think both sellers are
contributors to RAS) - but I'd like to get as much feedback as
possible from as wide of an audience as possible...

I've been agonizing (here and elsewhere) between the niceties of a
DG-300 and the flapped flexibilities of an ASW-20.

Someone just reminded me of the DG-202/17 on W&W (which I'd earlier
looked at and passed up), and they thought it might be worth
considering again as a potential "meet in the middle" option between
the DG-300 and the ASW-20.

On the one hand, the DG-202/17 isn't automatic hookups like the
DG-300; but it does seem to have the nicer canopy and much of the
prized ergonomics of the DG-300.

With flaps, it should have a flatter polar than the DG-300 (maybe not
100% ASW-20 performance, but possibly not degrade as much in the 65 -
80 knot range where the DG-300 and most other Std-Class ships really
start to lose out to flapped ships).

Again, I'm going to be flying in 2 - 5 knot lift with 4,000'
cloudbases a lot of the time; so raw speed isn't important to me in
terms of strong conditions... I just want to make enough speed to take
advantage of moderate day lengths and still go cross-country (as well
as fly in the desert a couple of times a year, and maybe compete in a
Regional each year in the Sports Class).

The 17m tips of the DG-202/17 are also intriguing. Coming from a
Russia AC-4 its would be quite a change if I go that route! But at
the same time, I often watch a local Open Cirrus just cruise (lumber)
along with its 17m wings on such a flat glide - I must admit I am
envious! I don't know what the DG-202/17 maneuverability is like; but
if it is decent then the extra span might be nice for those scratchy
days where I still want to stretch out and fly XC.

Of course, I don't know what condition this particular DG-202/17 is
in. JJ's DG-300 is getting all-new Urethane and a nice panel; so the
value there is well-known (and he knows it, too). But the DG-202/17
is selling for less, and the question is: How much less does it have
to be in order for the DG-202/17 to become a more attractive deal?

The bottom line is that I'm trying to get the best glider for my local
flying conditions (weak to moderate with low to middling cloudbases),
and my flying style (which requires crisp & responsive handling, good
cockpit ergonomics, and hopefully easy rigging). I am trying at this
point to view both gliders next week while I'm travelling to
California for vacation.

Any thoughts or details would be very much appreciated! I can't find
a good measured polar for a DG-202 (just 200's and 400's), so anyone
with a good polar for the aircraft and/or other information on the
detailed differences between the DG-200 and the DG-202 would be great
(I know what's on the Sailplane Directory, but its pretty basic info
about the differences)!

Thanks in advance,

--Noel

On Apr 17, 9:05*am, "D.Rizzato" wrote:
As long as you don't purchase one from Falcon Gauge
there are Chinese made, mine lasted 75 hours
and they like to charge me what ever it takes to
repair it, but will charge you up front $ 350 bucks
Cheers

"noel.wade" wrote in message

...



Hi All,

This is a bit of a loaded question (I think both sellers are
contributors to RAS) - but I'd like to get as much feedback as
possible from as wide of an audience as possible...

I've been agonizing (here and elsewhere) between the niceties of a
DG-300 and the flapped flexibilities of an ASW-20.

Someone just reminded me of the DG-202/17 on W&W (which I'd earlier
looked at and passed up), and they thought it might be worth
considering again as a potential "meet in the middle" option between
the DG-300 and the ASW-20.

On the one hand, the DG-202/17 isn't automatic hookups like the
DG-300; but it does seem to have the nicer canopy and much of the
prized ergonomics of the DG-300.

With flaps, it should have a flatter polar than the DG-300 (maybe not
100% ASW-20 performance, but possibly not degrade as much in the 65 -
80 knot range where the DG-300 and most other Std-Class ships really
start to lose out to flapped ships).

Again, I'm going to be flying in 2 - 5 knot lift with 4,000'
cloudbases a lot of the time; so raw speed isn't important to me in
terms of strong conditions... I just want to make enough speed to take
advantage of moderate day lengths and still go cross-country (as well
as fly in the desert a couple of times a year, and maybe compete in a
Regional each year in the Sports Class).

The 17m tips of the DG-202/17 are also intriguing. *Coming from a
Russia AC-4 its would be quite a change if I go that route! *But at
the same time, I often watch a local Open Cirrus just cruise (lumber)
along with its 17m wings on such a flat glide - I must admit I am
envious! *I don't know what the DG-202/17 maneuverability is like; but
if it is decent then the extra span might be nice for those scratchy
days where I still want to stretch out and fly XC.

Of course, I don't know what condition this particular DG-202/17 is
in. *JJ's DG-300 is getting all-new Urethane and a nice panel; so the
value there is well-known (and he knows it, too). *But the DG-202/17
is selling for less, and the question is: *How much less does it have
to be in order for the DG-202/17 to become a more attractive deal?

The bottom line is that I'm trying to get the best glider for my local
flying conditions (weak to moderate with low to middling cloudbases),
and my flying style (which requires crisp & responsive handling, good
cockpit ergonomics, and hopefully easy rigging). *I am trying at this
point to view both gliders next week while I'm travelling to
California for vacation.

Any thoughts or details would be very much appreciated! *I can't find
a good measured polar for a DG-202 (just 200's and 400's), so anyone
with a good polar for the aircraft and/or other information on the
detailed differences between the DG-200 and the DG-202 would be great
(I know what's on the Sailplane Directory, but its pretty basic info
about the differences)!

Thanks in advance,

--Noel- Hide quoted text -

- Show quoted text -

Noel:

The differences in the 15m vrs the Standard class is what you are
talking about. If you are set on having flaps then buy the flapped
ship. Either machine you go with will be a giant step forward with
respect to the AC-4. Handling, assembly, and all of that will be
noticably different and should be approached as with any new ship with
great care and attention to detail as to how to just get a circuit
under your belt. Cross country flying on the wet side of the
mountains will require carefully weighted descisions and execution to
provide you with a pucker free flight as in being closer to the ground
for the entire flight. I know many excellent flights have been made
on the west side of the mountains also. Consideration of outlanding
should also be taken into account. How much trouble is it to derig
and haul out of a field. What advantages if any does one have to off
field landings, cocpit safety structure, and susceptability for gear
doors to break and all that.

On the east side of WA you will have more altitude under you and the
flights longer most of the time. This gives you an advantage that you
can take more time to learn how you and your machine are getting
along. Long flights can be made with a little more ease.

It takes time to know your machine, it's polar and flight dynamics so
expect to take some time getting used to it. congratulations on your
ability to step up. Hope to see you in Ephrata soon.


T.Udd

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 Apr 16, 8:50*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

Hi Noel,

As others are pointing out, forget about the "glide performance" or
speed issues between two similar vintage glass ships with and without
flaps. I fly in similar conditions at a club where we have probably
30 glass birds of mixed vintages and performance. There is a very
direct correlation between the impressive flights and impressive
pilots; there is almost no correlation between impressive flights
and flaps.

Since you've already absorbed the importance of trailers and automatic
hookups etc, the one thing I would consider in the flaps/no-flaps
debate is the off-field landing capabilities. So, the better question
to be asking yourself is whether you are going to be "pushing" a bit
such that you are making a few more off-field landings each year. In
other words, are you going to become a more aggressive XC pilot. As
Eric Greenwell mentions, there's probably nothing out there that beats
an early model 20 with landing flaps for shoe-horning into tight
fields. By comparison, my old LS-4, though very forgiving, couldn't
quite get into as small of a field as a 20, plus it suffered from the
achiles heel of LS gliders - a puny undercarriage.

One other huge factor is instruments. If ship "a" has a modern
panel (say a Cambridge 302 plus PDA, good pneumatics, a Becker or
Filser radio) while ship "b" has older stuff (say an M-Nav,
questionable TE compensation, and an old Terra radio), the better
panel will almost certainly add more to your XC performance, not to
mention the resale value of the glider.

Finally, if you really want to "do the numbers", a 5% increase in
performance for a flight that would have taken 4 hours means you save
maybe 12 minutes.... Is that really going to mean a significant
difference in the ability to achieve long distance XC flights? I
doubt it.

My 0.02.

Erik Mann
LS8-18 (P3)