On 14/07/14 2:55 PM, "Rob Izatt" <[email protected]> wrote: Our reply hereunder:
We must be on the ball! Only last week, I approved the costs of Aldo Cernezzi's travel to the TwinShark factory for a write up on the plant and their M.D.'s stated goals for this new two seater. Comments filtering through seem they have goals and hopes 'over the moon'. Hope to have it all on hand to appear in the space reserved in our next issue. John Roake > HpH have been spending considerable time and money on this point with > engineers who specifically work in the wide body jet area. The TwinShark has > been delayed as the boss is adamant he wants something better. One of the > primary areas they are also working on is the weight of non flying parts - > fuselage. The factory does risk missing the boat with the Arcus/32/JS2 unless > of course it is great. > >> On 14 Jul 2014, at 12:39 pm, Richard Frawley <[email protected]> wrote: >> >> 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/20140 >>> 713/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]>[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 >>>>> <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/20140 >>> 714/8cd662e4/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
