Agreed. But the glide performance of modern WB jets improves with every generation and the time and distance to target at near idle on decent is a huge fuel saving.
> On 14 Jul 2014, at 1:15 pm, "Rod Merigan" <[email protected]> wrote: > > I think the efficiency for jet liners would be the cost/seat/mile, more > efficient engines and more bums on seats, > Cutting weight with use of composites. > > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Richard > Frawley > Sent: Monday, 14 July 2014 10:39 AM > To: [email protected] > Subject: Re: [Aus-soaring] Aus-soaring Digest, Vol 130, Issue 19 > > what is presented here seems to be in contradiction to the successes and > efficiency of wide body jets vs their narrow body predecessors. > > I would be very interested to hear from design experts in this thread. From > what i have read from experts elsewhere, it appears to be not the cross > sectional area of the fuze that makes the difference, but the actual overall > design (to maintain laminar flow and minimize separation) and particularly > the efficiency of the interface between fuze and the wing that can have > significant effect. > > > > > > At 10:30 PM 13/07/2014, you wrote: >> Send Aus-soaring mailing list submissions to >> [email protected] >> >> To subscribe or unsubscribe via the World Wide Web, visit >> http://lists.internode.on.net/mailman/listinfo/aus-soaring >> or, via email, send a message with subject or body 'help' to >> [email protected] >> >> You can reach the person managing the list at >> [email protected] >> >> When replying, please edit your Subject line so it is more specific >> than "Re: Contents of Aus-soaring digest..." >> >> >> Today's Topics: >> >> 1. Re: 20M gliders (Matthew Scutter) >> 2. Re: 20M gliders (Mike Borgelt) >> >> >> ---------------------------------------------------------------------- >> >> Message: 1 >> Date: Sun, 13 Jul 2014 16:18:50 +1000 >> From: Matthew Scutter <[email protected]> >> Subject: Re: [Aus-soaring] 20M gliders >> To: "Discussion of issues relating to Soaring in Australia." >> <[email protected]> >> Message-ID: >> >> <CALubygTZ5j=A3Mj-4eiXPJAZTcxKN0uBQ=co_x5eb_lxfke...@mail.gmail.com> >> Content-Type: text/plain; charset="utf-8" >> >> I see EB has essentially fit two pilots in a single seat EB29 with >> their EB29D ( >> http://www.binder-flugmotorenbau.de/eb29d-racing-doppelsitzer.html?&L=1 >> ), so I expect there is plenty of scope for improvement in fuselage >> size with ergonomic innovations. >>> On 12 Jul 2014 22:34, "Harry" <[email protected]> wrote: >>> >>> Mike, >>> >>> It?s all about driving a large fuselage through the air. The quite >>> small size difference between say, a Discus A and B fuselage makes >>> an appreciable difference in performance, particularly at higher >>> speeds. Compare the massive size difference between an ASG 29 and a >>> two seater fuselage. I don?t know what the actual drag figures are >>> but they must be a large difference. Likewise the two seater ASH 25 >>> and Nimbus 3DMs and 4DMs are left far behind the ballasted 18 metre >>> gliders when the speeds get up a bit. The actual Arcus fuselage is >>> very similar to the 20 year old Nimbus 3D fuselages so I guess there >>> was not much scope to improve them much.The Jonkers JS fuselage is >>> reputed to be an exact copy of an earlier German glider. Actually >>> expected the new Schleicher 32 fuselage, being a new design, to have >>> lesser drag but the information from Finland is not indicative of a >>> substantial improvement. Time will tell. Am sure you could give us >>> some useful information on drag calculations, >>> >>> Harry Medlicott >>> *From:* Rob Izatt <[email protected]> >>> *Sent:* Saturday, July 12, 2014 7:09 PM >>> *To:* Discussion of issues relating to Soaring in Australia. >>> <[email protected]> >>> *Subject:* Re: [Aus-soaring] 20M gliders >>> >>> You can get two people in a two seater and share the fun which is >>> the wholepoint of said two seaters. Without handicaps glider comps >>> would be even less viable. >>> >>> On 12 Jul 2014, at 5:59 pm, Mike Borgelt >>> <[email protected]> >>> wrote: >>> >>> From what has been written here over the last few days, it is >>> disappointing that a new flapped 20M two seater doesn't have as good >>> performance as a 15M unflapped glider. >>> >>> Mike >>> >>> >>> *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] >>> To check or change subscription details, visit: >>> http://lists.internode.on.net/mailman/listinfo/aus-soaring >>> >>> ------------------------------ >>> _______________________________________________ >>> Aus-soaring mailing list >>> [email protected] >>> To check or change subscription details, visit: >>> http://lists.internode.on.net/mailman/listinfo/aus-soaring >>> >>> >>> _______________________________________________ >>> Aus-soaring mailing list >>> [email protected] >>> To check or change subscription details, visit: >>> http://lists.internode.on.net/mailman/listinfo/aus-soaring >> -------------- next part -------------- An HTML attachment was >> scrubbed... >> URL: >> <http://lists.internode.on.net/mailman/private/aus-soaring/attachments/ >> 20140713/e742ec97/attachment.html> >> >> ------------------------------ >> >> Message: 2 >> Date: Mon, 14 Jul 2014 12:00:07 +1000 >> From: Mike Borgelt <[email protected]> >> Subject: Re: [Aus-soaring] 20M gliders >> To: "Discussion of issues relating to Soaring in Australia." >> <[email protected]> >> Message-ID: <[email protected]> >> Content-Type: text/plain; charset="iso-8859-1"; Format="flowed" >> >> Rob, >> I've done enough 2 seat cross country flying to realise the fun >> involved, I'm talking aerodynamics. >> >> Harry, >> >> There may be more wetted area and cross section on the 2 seat fuselage >> but comparing a Discus2 B to an Arcus (this necessarily approximate) I >> get about 32% more cross section on the Arcus fuselage and about 49% >> more wetted area. Shape is similar so I'd expect similar drag >> coefficients. >> The mass is 800 Kg vs 525 at gross which is 52% greater so at any given >> sink rate the POWER is 52% greater. The wing area is 15.6 M^2 vs 10.16 >> M^2 so a ratio of 1.54 (rounded up). >> No large differences (slightly worse at 750Kg) and as the Arcus has >> flaps I'd expect it to perform the same at mid range speeds and better >> at high speeds where the Standard Class glider starts to go out of the >> low drag region of the airfoil. >> Span loading is different though (mass per unit >> span) for the Arcus 800/20 =40, for the D2 525/15 35. Induced drag is >> dependent on the square of the span loading - derived here >> http://aerocrafty.blogspot.com.au/2013/06/span-loading.html >> (weird website behaviour on my office PC but works Ok in the iPad in >> Chrome) so yes, the two seat Arcus and ASG32Mi likely will climb worse >> than the 15M standard class glider even though the Reynolds numbers on >> the Arcus wing are 15% higher (lower profile drag coefficient). Why the >> high speed performance is worse is a mystery. >> >> I don't have any numbers on the height and width of the ASG32 fuselage >> but if less than that of the Arcus I'd expect an improvement. >> >> I wouldn't draw any conclusion about the ASG32 performance from Finland >> except that it is clearly not a terrible glider in performance compared >> to the Arcus and looks nice. >> >> Mike >> >> >> >> >> At 10:33 PM 12/07/2014, you wrote: >>> Mike, >>> >>> It???s all about driving a large fuselage through the air. The quite >>> small size difference between say, a Discus A and B fuselage makes an >>> appreciable difference in performance, particularly at higher speeds. >>> Compare the massive size difference between an ASG 29 and a two >>> seater fuselage. I don???t know what the actual drag figures are but >>> they must be a large difference. Likewise the two seater ASH 25 and >>> Nimbus 3DMs and 4DMs are left far behind the ballasted 18 metre >>> gliders when the speeds get up a bit. The actual Arcus fuselage is >>> very similar to the 20 year old Nimbus 3D fuselages so I guess there >>> was not much scope to improve them much.The Jonkers JS fuselage is >>> reputed to be an exact copy of an earlier German glider. >>> Actually expected the new Schleicher 32 fuselage, being a new design, >>> to have lesser drag but the information from Finland is not >>> indicative of a substantial improvement. Time will tell. Am sure you >>> could give us some useful information on drag calculations, >>> >>> Harry Medlicott >>> From: <mailto:[email protected]>Rob Izatt >>> Sent: Saturday, July 12, 2014 7:09 PM >>> To: >>> <mailto:[email protected]>Discussion >>> of issues relating to Soaring in Australia. >>> Subject: Re: [Aus-soaring] 20M gliders >>> >>> You can get two people in a two seater and share the fun which is the >>> wholepoint of said two seaters. Without handicaps glider comps would >>> be even less viable. >>> >>> On 12 Jul 2014, at 5:59 pm, Mike Borgelt >>> <<mailto:[email protected]>mborgelt@borgeltinstruments. >>> com> >>> wrote: >>> >>>> From what has been written here over the last few days, it is >>>> disappointing that a new flapped 20M two seater doesn't have as >>>> good performance as a 15M unflapped glider. >>>> >>>> Mike >>>> >>>> >>>> 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 >>>> <mailto:[email protected]>[email protected] >> node.on.net >>>> To check or change subscription details, visit: >>>> <http://lists.internode.on.net/mailman/listinfo/aus-soaring>http:/ >> /lists.internode.on.net/mailman/listinfo/aus-soaring >>> >>> >>> ---------- >>> _______________________________________________ >>> Aus-soaring mailing list >>> [email protected] >>> To check or change subscription details, visit: >>> http://lists.internode.on.net/mailman/listinfo/aus-soaring >>> _______________________________________________ >>> Aus-soaring mailing list >>> [email protected] >>> To check or change subscription details, visit: >>> http://lists.internode.on.net/mailman/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 >> -------------- next part -------------- An HTML attachment was >> scrubbed... >> URL: >> <http://lists.internode.on.net/mailman/private/aus-soaring/attachments/ >> 20140714/8cd662e4/attachment.html> >> >> ------------------------------ >> >> _______________________________________________ >> Aus-soaring mailing list >> [email protected] >> http://lists.internode.on.net/mailman/listinfo/aus-soaring >> >> End of Aus-soaring Digest, Vol 130, Issue 19 >> ******************************************** > > _______________________________________________ > Aus-soaring mailing list > [email protected] > To check or change subscription details, visit: > http://lists.internode.on.net/mailman/listinfo/aus-soaring > > _______________________________________________ > Aus-soaring mailing list > [email protected] > To check or change subscription details, visit: > http://lists.internode.on.net/mailman/listinfo/aus-soaring _______________________________________________ Aus-soaring mailing list [email protected] To check or change subscription details, visit: http://lists.internode.on.net/mailman/listinfo/aus-soaring
