At 04:16 PM 7/08/2011, you wrote:
1. Our understanding of the aerodynamics within the "usual" gliding envelope
in which gliders operate, has increased immensely. Research on the
aerodynamics of a wing section (as always, carried out by dedicated
enthusiasts), has led to a huge performance increase, in a relatively short
period of time.
A state of the art glider design of "today " is certainly of substantially
better aerodynamic design than one that is say 15 years old. It is highly
likely that it better than one that was designed 5 years ago.
******************
I'm going to disagree with this. The big breakthrough was the
tailoring of airfoil sections instead of designing out of the
Stuttgart Profilkatalog.
The first production glider to do this was the Ventus A, Nimbus 3
(Ventus A wings as outer panels) followed by the LS4. The LS4 was a
result of an experiment by Streifeneder when it was noticed that an
LS3 with the flaps fixed went better than any existing Standard Class
glider - mainly Cirrus and Hornet at the time. In the US the ASW20
with flaps fixed to zero was winning all the Standard Class contests
also. I think they banned them in 1981. So it was a no brainer to
design a better Standard Class glider. The 15M class was more
difficult as the ASW20 was very good and here Holighaus, Althaus and
some others did a lot of work on theoretical wing section design and
verified with wind tunnel and flight test. The A model Ventus has 4
sections on the wing optimised over the span. This is all easier
nowadays as we all have supercomputers on our desktop and the MIT
XFOIL program (free!) has been verified by experiment at all
Reynolds numbers and the limitations are known. The JS1 was designed this way
The other breakthrough was the ability to build what was designed and
there have been significant developments in the molds for the wings.
The Discus was the first of these gliders(1983) and the LS6 came out
around the same time. It only took LS 10 years to realise what they
had done and fly an LS6 with the flaps fixed and realise it was
better than a Discus 1. They should have known this much earlier as
they had the DLR polar which showed the flaps on the LS6 didn't do much!
Note this was all a long time ago. The current ASG29 is a ASW27 with
new stretched outer wings. The ASW27 was designed in 1991 - 20 years
ago! Ventus 2 came out in 1995.
The ASH31Mi is a ASH26E with fuel injected engine and a 2.5 meter
section of the wing in the middle designed to match the inner ASH26
wing to the outer wings of the ASG29.
Gary Ittner and Graham Parker will tell you that Ventus C with A
fuselage and winglets is as good as an ASW27.
Progress!!!
Here I am talking about the design only - as opposed to design and
production. Some
designs may be absolutely revolutionary, but for one reason or another the
glider itself may never gets into real serial production - think
Diana 1, (5 or 6 produced), and
maybe (more so) Diana 2.
If I heard Todd Clark (the Australian Agent for the
JS1), rightly, last year at Dalby he said that the estimated
manhours to get the JS1 Revelation
into production was 75,000 hours! {Todd please confirm!} All these,
and the actual set up and production costs have to be met before a
single glider rolls off the line!
So we have a design phase, and a production phase. If the actual
elapsed time (as opposed
to manhours), from design to production can be minimized, then the company
doing this best will have an advantage over its competitors.
The JS1 is an amazing effort and clearly as good as the ASG29/V2.
They may like to think about pulling some carbon out of the wing. You
don't really need a glider capable of breaking the test rig at 15 g
(8 g is all that is required) and then being able to put those wings
on the prototype and go flying. Nor do you need 90 Kg wing panels.
********************
2. There has been a significant advance (over a relatively short period of
time), in the development of instrumentation that allows the pilot
to know (in real time), what is happening in the airmass he is
flying in, and what to
do about it. Someone like Mike Borgelt might like to make comment
here, and gaze into the crystal ball!
Nope again. I flew our first pressure transducer vario in 1981 and
Richard Ball and the Swiss Pirol guys did it some years before. I'd
been looking at it since the National Semiconductor Pressure
Transducer Handbook came out in 1974 but the early transducers
weren't very good.
Really we're still doing it the same way. Displays and audios have
been refined and software driven instruments and stepper motor
driven pointers make things like the expanded and non linear scale on
the B700 and B800 easy to do (they work really well too) and audios
are more informative - even to two speakers to provide direction information.
The pressure transducer/Irving type TE probe combination produce
instruments with very high performance/simplicity ratio but ALL
present total energy instruments are subject to the effect of
horizontal gusts. If you haven't been told about them read the
article on our website. The problem has been known about for a long
time - I've seen it in a Soaring Symposium Proceedings dated 1969
but it is difficult to solve at a cost that any glider pilot will
pay. I hate to think what a tactical grade Inertial Nav platform
costs. These gusts introduce "noise" into the vario signal of about
the same time period and magnitude as the vario signals(vertical air
motion) that we want.
We do, however, have some good ideas on this and are designing the
hardware and software for a horizontal gust compensator. In my
opinion this is the last interesting problem in soaring
instrumentation. I'm not a fan of distant thermal indication.
There are some advances to be made in display and interface
technology. Current computers require ridiculous amounts of pilot
interaction and interpretation of the display. In an era of moving
maps people are STILL missing turnpoint sectors. There is scope for
simplification. It is easy to design something complicated, hard to
make it simple for the end user. We're trying with the
averager/integrator comparison on the B700/B800.
Contest rules people could help. The AAT was a brilliant, nearly
successful, attempt at an uncomputable problem. Right away lots
more display capability, interpretation and interaction is required.
Multiple startpoints likewise.
Always remember the aim is to have fun flying gliders, not to operate
computers in glider cockpits while trying to fly.
Mike
Borgelt Instruments - manufacturers of quality soaring instruments since 1978
phone Int'l + 61 746 355784
fax Int'l + 61 746 358796
cellphone Int'l + 61 428 355784
email: mborg...@borgeltinstruments.com
website: www.borgeltinstruments.com
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