There has long been a suspicion that a high wing
location would be better to get a better lift distribution across the span.
Putting a wing on a pylon above the fuselage
still gives you 4 intersections and the drag of the pylon.
The problem with the high wing is the lower
intersection of the wing root with the fuselage
and the interaction of the leading edge of the
wing with the fuselage. Note the JS3 in that
area also. Re-entrant intersections are
particularly bad and as I noted, in the past
the CFD tools have not been available to quickly determine promising shapes.
The Mu 31 attempts to overcome this by careful
shaping in the underwing/fuselage junction and
leading edge, lots of CFD and wind tunnel testing
and getting only 2 intersections instead of
4 Nowadays wind tunnels in the subsonic turbulent flow regime are used to
verify the CFD results and are very successful.
It was smart to base this heavily on the ASW27 as
it should take all of an hour or so to do a
comparison glide with an ASW27 at the same wing
loading after a dual tow to 10,000 feet, at
least as a first cut. It has been in development for 10 years. Note Jonkers
have their own Akaflieg in the pool of
engineering students at Northwestern University.
I've seen a paper on the web on the Mu 31 design
with CFD results, flow tests etc. IIRC they are
talking 6 to 10% improvement depending on speed.
If it really gets half that, expect to see some
changes in new designs or modifications of old ones particularly if the
JS3 is shown to go well. Not a given when it gets
down to survival conditions although it will go
well on good days. The hit rate on successful
competition gliders designed to be such isn't anywhere near 100%.
Mike
At 08:20 AM 12/29/2017, you wrote:
Hi Ross
Whether it is a good idea or not remains to be seen.
Please keep in mind that the Mü 31 is only a
student research project. Its existence should not be seen as an indication
that a high wing design is beneficial in terms
of performance. In fact there are very significant aerodynamic disadvantages
with this concept and one of them is the huge
amount of parasite drag on the underside of the wing/fuselage junction.
There are others too, and it is high noon that
this hype comes down to a more rational level.
Please donât think for a moment that the move
away from the early high wing designs on composite gliders wasnât made
for very good reasons.
Kind regards
Bernard
On 29 Dec 2017, at 8:16 am, Ross McLean
<<mailto:[email protected]>[email protected]> wrote:
And yet the European manufacturers have ignored
their own research for so many years.
It took the South African Jonkers brothers to
put it into production again with their outstanding 15m/18m JS3 Rapture.
Now suddenly the Akaflieg have realised it was a good idea after all.
ROSS
_________________________________________________________________________________________
Ross McLean
Mobile: + 61 488 270 105
Telephone: + 61 7 4325 4771
From: Aus-soaring
[<mailto:[email protected]>mailto:[email protected]]
On Behalf Of Peter Champness
Sent: Thursday, 28 December 2017 5:37 PM
To: Discussion of issues relating to Soaring in Australia.
Subject: Re: [Aus-soaring] ASG29R
I attended a talk by Gerhard Waibel about 10
years ago (or maybe 15 years ago).
Among other things he talked about the wing
fuselage intersection drag. His idea was to
raise the wing on a thin pylon more than 200mm
above the fuselage and then support the wing
with struts! I thought that was really
reinventing the wheel. But he was right. Here we go.
On Thu, Dec 28, 2017 at 8:22 AM, Mike Borgelt
<<mailto:[email protected]>[email protected]>
wrote:
Yes, as Bernard said there are other composite
sailplanes with high wings. Phoebus C, Std Jantar 2/3, ASW 15.
However have another look at the Mu 31, the
fuselage cross section in particular where at
around pilot shoulder height it necks in. This
is more like the Weihe, Meise (Olympia),
Slingsby Sky, early Slingsby Skylarks etc.
Mike
the At 01:08 PM 12/27/2017, you wrote:
Not just new wings (same sections though ) but
extensive changes to fuselage also so I think a
new model number is warranted. Better for sales
anyway. Wouldn't surprise me if the EB29R is
further modified and becomes the EB30. Looking
at the R wing at Benalla it didn't really fit
the old root fairings on the EB29.
Funny thing is some of the wooden gliders of
the 30s, 40s and 50s had similar wing locations
and mounting of the wings on a pylon integrated
into the fuselage. Didn't have the fancy wing
root design as they didn't have the CFD codes or computers then.
Somewhere I have a paper on the Mu31 where they
say they hope to get 6 to 10% drag reduction
with the wing location. We should know soon as
it won't be hard to find a good ASW27 and do comparison flights.
Before anyone gets too excited this is all pure
speculation on my part but if the comparison
tests show they are getting what they wanted........
Mike
At 12:43 PM 12/27/2017, you wrote:
Content-Language: en-US
Content-Type: multipart/alternative;
boundary="_000_PS1PR04MB1004D9231BF7DE336AFA7056A2070PS1PR04MB1004apcp_"
Hearing that this will be the glider that
combats the V3 & JS3; new wings for the very
popular ASG29, the R is for Racing - perhaps a play on the intimidating EB29R?
"ROCKS" ?
Looks like Butch had a good time in the V2 aswell.
Jim
what does that mean??
_______________________________________________
Aus-soaring mailing list
<mailto:[email protected]>[email protected]
http://lists.base64.com.au/listinfo/aus-soaring
Borgelt Instruments - design & manufacture of
quality soaring instrumentation since 1978
<http://www.borgeltinstruments.com/>www.borgeltinstruments.com
tel: 07 4635 5784 overseas: int+61-7-4635 5784
mob: 042835 5784 : int+61-42835 5784
P O Box 4607, Toowoomba East, QLD 4350, Australia
_______________________________________________
Aus-soaring mailing list
<mailto:[email protected]>[email protected]
http://lists.base64.com.au/listinfo/aus-soaring
Borgelt Instruments - design & manufacture of
quality soaring instrumentation since 1978
<http://www.borgeltinstruments.com/>www.borgeltinstruments.com
tel: 07 4635 5784 overseas: int+61-7-4635 5784
mob: 042835 5784 : int+61-42835 5784
P O Box 4607, Toowoomba East, QLD 4350, Australia
_______________________________________________
Aus-soaring mailing list
<mailto:[email protected]>[email protected]
http://lists.base64.com.au/listinfo/aus-soaring
_______________________________________________
Aus-soaring mailing list
<mailto:[email protected]>[email protected]
http://lists.base64.com.au/listinfo/aus-soaring
_______________________________________________
Aus-soaring mailing list
[email protected]
http://lists.base64.com.au/listinfo/aus-soaring
Borgelt Instruments - design & manufacture of
quality soaring instrumentation since 1978
www.borgeltinstruments.com
tel: 07 4635 5784 overseas: int+61-7-4635 5784
mob: 042835 5784 : int+61-42835 5784
P O Box 4607, Toowoomba East, QLD 4350, Australia
_______________________________________________
Aus-soaring mailing list
[email protected]
http://lists.base64.com.au/listinfo/aus-soaring
