ASW 24 low speed handling and performance
Christopher Carlyle O'Callaghan
In the January issue of Soaring Pilot Magazine in
the Rumor Mill section, I reported that some 24
owners have voiced discontent witht with the low
speed handling and performance of the ASW 24. Most
of these reports have likened the 24 to the A and
B model Ventus in its need for complete pilot atten-
tion. John Murray is, of course, upset with the report.
In deference to him, I'd like to get comments from those
of you who fly the 24 to increase my sampling. If you
would prefer to keep your comments anonymous, send them
to me directly. Thanks...
Chris O'Callaghan
Editor, Soaring Pilot Magazine
.
Christopher Carlyle O'Callaghan
Thanks for the info. I'm especially interested in the
flying characteristics of the 24 in the blunt wing
configuration. A number of pilots have expressed
disatisfaction with its handling sans winglets. Of
course, anything less than cream puffy is unusual for
a Waibel design. The "spike" in the low end polar you've
noticed may be the cause for the consternation. I'd be
interested to hear your impressions of the ship's hand-
ling without the winglets should you fly it that way. Some
comparison climbs with he same ship would be appropriate.
It's clear that the 24 is a fine glider, its attention to
detail and pilot safety is unsurpassed. But the reports of pilots
that they are not comfortable with its low speed characteristics
are not to be dismissed. No matter what the right side of the
polar proves, if a pilot is uncomfortable flying low and slow,
he has given up an important performance aspect of his ship. 35:1
at 100 knots means nothing to a pilot in a field.
.
ma...@aslvx1.sugar-land.ana.slb.com
Some comments on flying characteristics of the new generation of
Standard class gliders:
Jacques Aboulin, (world std class champ 1989) mentioned that the
French team had tested the '24 and found that it was indeed higher
performance than the Discus, but that the glider definately
took more finesse in flying to achieve this than the Discus.
He mentioned a minimum of 50 hours flying time before you were
comfortable in the '24.
When glider designers try to eek out more performance from their
new machines, they often trade of one parameter against another to
get what really sells new gliders - high max L/D. In airfoil design,
you can get lower drag by selecting an airfoil with a narrower
laminar 'bucket'- this usually means a thin cross-section. The
drawback is always that the drag outside of the laminar zone is
much higher than it would be for a wider laminar bucket airfoil.
A case in point is the DG-600 - it has the thinnest section and
the highest measured L/D for a 15-meter ship, but poor climb
performance. It hasn't won very many contests.
It will be interesting to see how the ASW-27 does. Waibel is
claiming a very high L/D - it's got a very small wing ...
but will it climb ?
Several years ago, several of us did some experiments with a
device we called the 'Rising Air Pointer'. This device measured
angle of attack at each tip. When flying in turbulent air,
it was remarkable how large the angle of attack variations were -
easily +/- 10 degrees at the tip. Since the laminar bucket is
only +/- 2 degrees for the airfoil. it's not surprising that
those gliders that measure excellent still air L/D's never
quite perform as well as expected in real flying conditions.
(the tips were constantly transitioning into turbulent,
high drag flow).
Peter Masak, Houston, TX
>
>
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Ian Spence
Christopher Carlyle O'Callaghan <asd...@wam.umd.edu> wrote:
>
>In the January issue of Soaring Pilot Magazine in
>the Rumor Mill section, I reported that some 24
>owners have voiced discontent witht with the low
>speed handling and performance of the ASW 24. Most
>of these reports have likened the 24 to the A and
>B model Ventus in its need for complete pilot atten-
>tion. John Murray is, of course, upset with the report.
>In deference to him, I'd like to get comments from those
>of you who fly the 24 to increase my sampling. If you
I did not see your article Chris so I cannot respond to
particulars. I got my ASW 24 last July and so far have
about 90 hours on it (and about 6500 XC kilometres).
I have flown with LS7, Discus, SZD 55 and I would say the
ASW 24 is equal or better on the run. In climb I would say
it is better than the LS7, about the same as the Discus and
perhaps just behind the SZD 55 which seems to be an awfully
good climber. BTW, my 24 has winglets and I'm talking about
flight in that configuration (I haven't yet flown it without
the winglets! Maybe this Spring ...)
In my club, I fly a lot with Ed Hollestelle (Ventus B) and
Wilfried Krueger (LS6). I find that I can run with both up
to 85-90 kts with no problem. I can generally outclimb the
Ventus, but it's hard for me to stay with the LS6 in the
climb, sometimes.
The handling is not as simple/easy/nice as an LS4, for example,
but I would say it is about the same as a Discus (I have 20+ hours
in a Discus). The aircraft is responsive and rolls 45-45 fairly
quickly. I found that it took quite a bit of experimentation
with speed and bank angles to optimize the climb. At first I
found getting the ship to climb well a little tricky. I have
the impression that there is a low speed transition point where
the sink rate goes up rapidly so it does not pay to circle too
slowly. (I'm looking forward to seeing Dick Johnson's report
on the ASW 24--I gather he is testing one now.)
I have not flown the Ventus A or B so I can't comment on
the comparison, but I would say that the 24 is not a difficult
ship to fly, nor does it require constant attention. It's not
as sweet as my old LS4, but it requires a lot less attention
than my even older Jantar Standard 2.
The glider is beautifully constructed. It is spacious and
comfortable and has excellent visibility. Assembly is
straightforward and quick. And it looks better than all
the other new ships :-)
Frankly I prefer the ASW 24 to the Discus (in the 93 US Nationals
24s won more days than Discuses, even though there were many more
Discuses flying!)
If you have any further specific questions I'd be happy to give
you my point of view.
Ian Spence (WW)
--
Ian Spence, Department of Psychology spe...@psych.utoronto.ca
University of Toronto spe...@psych.toronto.edu
Toronto, Ontario (416) 978-7623 (Voice)
Canada M5S 1A1 (416) 978-4811 (FAX)
Ian Spence
<ma...@ASLVX1.SUGAR-LAND.ANA.SLB.COM> wrote:
[ snip ... ]
>
>Several years ago, several of us did some experiments with a
>device we called the 'Rising Air Pointer'. This device measured
>angle of attack at each tip. When flying in turbulent air,
>it was remarkable how large the angle of attack variations were -
>easily +/- 10 degrees at the tip. Since the laminar bucket is
>only +/- 2 degrees for the airfoil. it's not surprising that
>those gliders that measure excellent still air L/D's never
>quite perform as well as expected in real flying conditions.
>(the tips were constantly transitioning into turbulent,
>high drag flow).
>
>Peter Masak, Houston, TX
I have heard that Waibel claims that one of the (unforseen?)
advantages of adding winglets to the ASW 24 is that the winglets
counteract the problem of tip separation that seems to occur with
the normal tip on the ASW 24. Waibel says that their tests show
not only better glide with the winglets but also improved climb
due to the better tip airflow attachment.
I'd be interested in your comments on this, and also on how it might
relate to what you wrote above.
BTW, I can relate to Jacques Aboulin's comment that a minimum of
50 hours are necessary to get comfortable with the ASW 24. I now
have about 90 hours on mine and am only just beginning to feel I
can get the best from it. (But again I would like to emphasize
that the 24 is not tricky or difficult to fly--it just takes time
to get the best from it, probably for the reasons Peter has
mentioned.)